Lemon Shark Population Decline Due to Bimini Resort Dredging

Alex Brown 2004
EA0371 Marine Geography Dissertation 1
THE IMPACTS OF DREDGING AND HABITAT
DESTRUCTION ON THE LEMON SHARK, NEGAPRION
BREVIROSTRIS, POPULATION OF BIMINI, BAHAMAS.
“Dissertation submitted as part of the requirements for the BSc Degree in
Marine Geography with Honours”
Signed…………………………………………..20/02/04
Alex Brown

Alex Brown 2004
ACKNOWLEDGEMENTS
I wish to thank all of those people who helped me complete this project. The Bimini
Biological Field Station and its staff for providing the data and a wealth of advice; Dr
Samuel Gruber for the countless emails, newspaper articles and additional resources which
he provided; Neil Sealey for his expertise and suggestions; Renata Kowalik for her help with
statistics; Mike Early for diagrams and lessons on Photoshop; and of course Dr Vicki Howe
for all her encouragement. Thank you also to Grant Johnson and Steve Kessel for their
photographic contributions.

Alex Brown 2004
ABSTRACT
The islands of North and South Bimini, Bahamas, surround a shallow tropical lagoon
interspersed with lawns of seagrass and fringed by mangroves. This lagoon serves as an
important nursery ground for many species of reef fish including Negaprion brevirostris, the
lemon shark. Since 1995, a sampling procedure has been carried out annually in two key
nursery locations within the lagoon, attempting to capture and tag every juvenile lemon shark
within each nursery. Data collected from this sampling procedure allows close monitoring of
these populations of sharks over the past 9 years. Between late 1999 and 2002, dredging of
the lagoon bottom associated with a large tourist development has occurred within close
proximity to these nursery areas, causing severe sedimentation and habitat destruction.
Analysis of the sampling data allowed several characteristics of the lemon shark populations
to be compared for the periods pre-dredging (1995 – 1999) and post-dredging (2000-2003).
Post-dredging the population size in one nursery fell considerably. It was also found that
post-dredging, a significant reduction in the average growth rate, total length and weight of
sharks occurred within the nurseries. The 1st
year survival rate of newborn sharks also
dropped considerably during the post-dredging period. In addition to this, sharks captured at
times when the dredging was at its most intense showed abnormal signs of severe
physiological and neurological stress, leading to an elevated level of mortality within
captured sharks. The carrying out of dredging activities, combined with destruction of
mangrove habitats correlates very closely with the observed reductions in growth, survival,
size and general health of the sharks within the lagoon. The nursery habitat of the North
Sound appears to be more fragile and vulnerable to the effects of dredging than the
neighbouring nursery of Sharkland. Further dredging activity could destroy these nursery
habitats.

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“A couple of miles long and a few hundred yards wide. Maximum elevation is roughly one
palm tree high. Twin dirt roads optimistically named the King and Queen's highways. No
cruise ships, casinos or mega-resorts. Plenty of golf carts but no golf courses. Traffic is
defined as a boat anchored in the way of the seaplane. The island of Bimini has been called
a glorified sandbar. And therein lies its enduring appeal.”
David Kresge, 2003.

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CONTENTS
1. INTRODUCTION, AIMS AND OBJECTIVES…………………………………....1
1.1 Introduction to Study………………………………………………………………....2
1.2 Primary Aim…………………………………………………………………………..3
1.2.1 Objectives…………………………………………………………………...3
1.3 Secondary Aims……………………………………………………….………………4
2. BACKGROUND……………………………………………………………………....5
2.1 Study Area…………………………………………………………………………….6
2.2 Negaprion brevirostris and Bimini – a brief life history……………………………...9
2.3 The North Sound and ‘Sharkland’…………………………………………………...11
2.4 Tourist Development on Bimini……………………………………………………..14
2.5 RAV Ltd’s Bimini Bay Resort………………………………………………………16
3. METHODOLOGY…………………………………………………………………..21
3.1 Notes………………………………………………………………………………...22
3.2 PIT Tagging Methodology………………………………………………….……….22
3.3 Gill Netting…………………………………………………………………………..23
3.3.1 Working up a shark………………………………………………………...23
3.4 Analysis of PIT data…………………………………………………………………25
3.5 Statistics……………………………………………………………………………...26
4. DATA ANALYSIS…………………………………………………………………...27
4.1 Notes……..………………………………………………………...………………...28

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4.2 Catch Data………………………………………………………..…………………28
4.3 Size characteristics…………………………………………………...………...........31
4.4 Growth Rates…………………………………………………………………...…...32
4.5 First Year Survival Rates………………………………………………………...….35
4.6 Mortalities during PIT tagging scheme…………………………………………...…37
5. DISCUSSION……………………………………………………………………......38
5.1 Summary of BBR activities combined with identified trends………………...…….39
5.2 Explanation of Results……………………………………………………...……….41
5.3 Assumptions………………………………………………………………...………43
5.4 Direct effects on the lemon sharks………………………………………...………...43
5.4.1 Dredging……………………………………………………………….......43
5.4.2 Habitat Destruction………………………………………………………..44
5.5 Indirect effects on the lemon sharks…………………………………………………45
5.6 The importance of sharks to the marine environment……………………………….46
5.7 Effects of dredging and filling on the whole ecosystem…………………………….47
5.8 The future of Bimini Bay Resort…………………………………………………….50
6. STUDY CRITIQUE………………………………………………………………….56
6.1 Achievement of aims and objectives………………………………………………...57
6.2 Limitations of Study…………………………………………………………………57
7. CONCLUSION………………………………………………………………………60
7.1 Conclusion…………………………………………………………………………...61
REFERENCES…………………………………………………………………………63
APPENDIX……………………………………………………………………………...68

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LIST OF FIGURES, TABLES AND CHARTS
Figure 1. Vertical aerial photograph of Bimini, pre – 1990………………………………6
Figure 2. Red mangroves (Rhizophora mangle)…………………………………………7
Figure 3. Photograph showing underwater prop roots of mangroves…………………….8
Figure 4. Sketch of the lemon shark (N. brevirostris)……………………………………9
Figure 5. PIT tag………………………………………………………………………...10
Figure 6a). Aerial photograph of the North Sound, facing north………………………11
Figure 6b). Aerial photograph of ‘Sharkland’, facing south……………………………11
Figure 6c). Vertical aerial photograph of Bimini, pre - 1990…………………………...11
Figure 7. Photograph of less dense seagrass bed in the N. Sound………………………13
Figure 8. Photograph of more dense seagrass bed in Sharkland………………………...13
Figure 9. Bimini Sands, facing north……………………………………………………15
Figure 10. Drawing of the 3 development phases of RAV BBR……………………..…10
Figure 11. Access causeway, looking south………………………………………….…19
Figure 12. Diagram showing the current extent of development at the BBR site………20
Figure 13. Map of North Bimini…………………………………………………….…..22
Figure 14. Setting gill net……………………………………………………………......23
Figure 15. Shark caught in gill net………………………………………………………23
Figure 16. Shark placed in the tagging boat’s box……………………………………....23
Figure 17. Length is measured…………………………………………………………..23
Figure 18. The shark is weighed………………………………………………...……....24
Figure 19. PIT tag insertion. …………………………………………………………....24

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Figure 20. A DNA sample is punched out of the dorsal fin for genetic analysis…….…24
Figure 21. Shark transferred to the holding pen………………………………………...24
Figure 22. Sharks held in pen during PIT tagging scheme...............................................25
Figure 23. A juvenile lemon shark leaves the pen............................................................25
Figure 24. Aerial photo of the destruction at the BBR site, as of late 2001.....................45
Figure 25. Aerial photograph, 30/4/02..............................................................................49
Figures 26 & 27 . The BBR site, summer 2003................................................................50
Figure 28. Map of the latest proposed BBR development................................................51
Figure 29. The uninhabited mangrove swamps of east N. Bimini....................................52
Table 1. PIT tagging catch data.........................................................................................28
Table 2. Newborn sharks: odd and even years breakdown...............................................29
Table 3. Total length (TL) and weight (WT) averages of sharks caught..........................31
Table 4. Average growth rates per year in NS, SL and whole lagoon..............................33
Table 5. Average growth rates of sharks in the Bimini lagoon.........................................34
Table 6. First year survival rates of sharks........................................................................35
Table 7. % mortalities of sharks captured during the PIT tagging scheme.......................37
Table 8. Summary of BBR activities................................................................................39
Chart 1. Total Catch, recaptured & newborn sharks 1995 – 2003...................................30
Chart 2. First year survival rates of sharks: Pre, and Post Dredging................................36
A 1. The Bimini Islands, as shown on Chart 38B..............................................................69
A 2. Satellite image of the BBR site, as of 2001...............................................................70
A 3. Description of results of Kruskal-Wallis Tests..........................................................71
A 4. Map of proposed boundaries of the planned Bimini NTMPA...................................74
A 5. Personal communication: Gruber to Marshall...........................................................75

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ACRONYMS AND ABBREVIATIONS USED
ATM: Associated Technology and Management
BACI: Before After Control Impact
BBFS: Bimini Biological Field Station
BBGC: Bimini Big Game Club
BBR: Bimini Bay Resort
BEST: Bahamas Environment Science and Technology Commission
CEO: Chief Executive Officer
EIS: Environmental Impact Statement
HoA: Heads of Agreement
IGFA: International Game Fishing Association
IUCN: The World Conservation Union
NS: North Sound
NTMPA: No Take Marine Protected Area
PIT: Passive Integrated Transponder
RAV: RAV Bahamas Ltd
SL: Sharkland
TL: Total Length
WL: Whole lagoon
WT: Weight

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1. INTRODUCTION, AIMS AND OBJECTIVES

Alex Brown 2004
1.1 Introduction to Study
The lemon shark, Negaprion Brevirostris, is a large coastal elasmobranch belonging to the
carcharhinid family (the requiem sharks), a group of highly active, predatory sharks. Adult
females return to shallow lagoon habitats every other year to give birth to fully formed pups
– which spend the first few years of their lives within the lagoon (Feldheim at al., 2002). The
Bimini Islands in the northern Bahamas surround such a lagoon, supporting a large
population of juvenile lemon sharks. The shallow mangrove fringed lagoon with sea grass
beds serves as an excellent nursery ground, providing shelter from predators and an abundant
prey in the form of juvenile reef fish and small crustaceans.
Since late 1999, dredging and mangrove destruction within the Bimini lagoon for the
development of a large tourist resort has put populations of resident marine organisms under
extreme pressure. As the top predator in the Bimini lagoon ecosystem, the lemon shark is an
excellent indicator of the overall health of the lagoon (Feldheim & Edrén, 2002). At the top
of the food web, its presence is essential in order to maintain a balanced ecosystem, and any
changes in its population structure will have considerable effects on all trophic levels
beneath (Gruber et al., 2002).
Since 1995, the lemon shark population of the Bimini lagoon has been extensively sampled
by way of an annual tagging scheme known as PIT (Passive Integrated Transponder)
tagging. The results of this scheme provide an accurate year by year estimate of the
population structure and dynamics of the lemon sharks present – allowing close monitoring
of any changes or trends to the population over the past 9 years.

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1.2 Primary Aim
 To analyse shark catch data from the PIT tagging scheme along with data from previous
studies in order to identify impacts of habitat destruction and dredging, associated with
the Bimini Bay development, on the juvenile lemon shark population of Bimini lagoon.
1.2.1 Objectives
- Summarise PIT tagging data from 1995 - 2003 into spreadsheets and graphs
illustrating total catch, recaptured and newborn sharks.
- Compare the size characteristics (total length and weight) of captured sharks for each
year from 1995 – 2003, and between the two study sites.
- Using the measurements of size of recaptured sharks, calculate their year to year
growth rates.
- By observing the recapture rate of newborn sharks, estimate the average first year
survival rate of newborn sharks for each year of sampling.
- In addition to comparing year to year figures for the whole lagoon, breakdown each
of the above datasets into figures for the two study sites: North Sound and Sharkland,
so that the two areas may be compared.
- Average all aforementioned datasets into values for two main periods: 1995 – 1999
(prior to commencement of dredging activities); 2000 – 2003 (since dredging
activities commenced.
- Relate individual year results to chronology of development activities.

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- Where possible, use appropriate statistical techniques to identify significant trends
between datasets.
- Test the following Null hypothesis:
→ ‘There has been no significant change in: i) total length; ii) weight; and iii) growth
rate of sharks between pre-dredging (1995-1999) and post (2000-2003) periods’.
- Compose a table summarising evidence of ecological impacts from existing studies
along with findings from this study, and display alongside the chronology of
development and dredging activities that have taken place at the Bimini Bay site
since 1997.
1.3 Secondary aims
 To summarize impacts of the development activities on other marine communities
within the Bimini lagoon.
 To evaluate the likely future of the Bimini Bay development, and estimate the
potential impacts of continued habitat destruction and dredging to the Bimini
ecosystem, based upon impacts that have already been observed. Relate this to the
importance of sharks to the marine environment.

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2. BACKGROUND

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2.1 Study Area
Bimini, Bahamas (250
44’N, 790
16’W) consists of North and South Bimini, the two largest
landmasses in a group of sub-tropical islands and cays known as the Biminis, located in the
Northwest Bahamas on the edge of the Great Bahamas Bank, just 48 miles east of Miami,
Florida (see A1, appendix). It has an area of only a few square miles, much of which is
wetlands, forcing the majority of the population of just 1638 people to live in an area of just
over ½ a square mile on the north island (Gruber and Parks, 2002).
Figure 1. Vertical aerial photograph of Bimini, pre –
1990. Source: URL:1.
North Bimini
South Bimini
N
Alicetown Channel

Alex Brown 2004
Barely rising above sea level, Bimini’s main terrestrial flora consists of mangroves,
buttonwood Conocarpus erecta, coastal scrubs, herbs, and evergreen woodland at some
higher elevations (Hutton, 2002). As can be seen in figure 1, the two main islands form the
border of a shallow (0-2m deep) lagoon, occupying approximately 21km2
(Morrissey and
Gruber, 1993) containing shallow sand/silt flats interspersed with lawns of manatee grass
Syringodium filiforme and turtle grass Thalassia testudinum (Gruber et al., 1988). The
majority of the lagoon is lined with three species of mangroves: black, Avicennia marina,
red, Rhizophora mangle, and white, Laguncularia racemosa (Feldheim and Edrén, 2002).
As identified by Turekian (1957), tidal waters enter the Bimini lagoon via two main water
bodies and flows. Firstly, clean, high quality waters from the Gulf Stream to the west enter
via the Alice Town Channel (see fig. 1), on the south western most point of N. Bimini.
Figure 2. Red mangroves (Rhizophora mangle) lining a section of the North Sound, N.
Bimini. Photo: Alex Brown, 2003

Alex Brown 2004
Secondly, warmer, more saline waters may enter the lagoon from the Great Bahamas Bank to
the east.
‘Apart from being a productive shoreline ecosystem, mangroves can help stabilise dynamic
coastlines’ (Field, 2000). The importance of the mangrove and seagrass habitats of the
Bimini lagoon, however, is generally focussed on their ecological role. ‘Both the seagrass
beds and the mangrove prop roots are important habitats due to the structural complexity,
food, shelter, and protection from predators that they provide’ (Nagelkerken et al., 2000;
Newman & Gruber, 2002). Seagrass beds provide important nursery and feeding grounds for
coral reef fishes, reef associated predators and commercially important finfish (Newman &
Gruber, 2002). Mangroves serve a similar purpose to many marine fishes. Nagelkerken et al
(2000) showed that there is a high dependence of juveniles on mangroves as nursery areas.
One such species of marine fish is the lemon shark Negaprion brevirostris.
Figure 3. Photograph showing underwater prop roots of mangroves. They
provide both shelter for organisms, and a base for algae to grow on.
Source: Greenberg et al., 2000.

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2.2 Negaprion brevirostris and Bimini – a brief life history
The lemon shark is a large coastal elasmobranch belonging to the carcharhinid family (the
requiem sharks), a group of highly active, predatory sharks. Lemon sharks are the most
abundant elasmobranch found at Bimini and play a vital role in the ecosystem as a top
predator (Feldheim & Edrén, 2002). For several decades scientists have been studying the
lemon shark populations of Bimini, revealing extensive details of its early life history.
Morrissey & Gruber (1993) showed juvenile lemon sharks (from age 0; 50 – 70cm total
length) to remain close to the mangroves until they reach approximately 110cm total length
(TL), when they begin to utilise larger portions of the lagoon. In their tracking study, data
from 17 juvenile lemon sharks showed their average activity space (‘area in which an animal
spends the bulk of its time during a given period’ (Musick & McMillan, 2002)) to be just
0.68km2
, varying from 0.23km2
to 1.26km2
between individuals and positively correlated
with shark size. By 4 -5 years old (~120cm TL) they begin to explore the banks (i.e. Great
Bahamas Bank) and reef but still remain close to the islands, not fully moving out to the
banks until they are sub-adults of 7-8 years old (Gruber et al., 2002). Home range studies of
Figure 4. Sketch of the lemon shark (N. brevirostris), showing main distinguishing
features. Adapted from: Allen, 1999.
Large second
dorsal fin
Short snout
Pale yellow underbelly

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adults have yet to be performed, however adults are seen at Bimini in late winter and early
spring – of which the adult females were either: pregnant or had recently given birth, or had
recently mated (Gruber, personal observation). Feldheim et al. (2001) found that adult
female lemon sharks return to Bimini for parturition (to give birth), using the lagoon as a
nursery ground. Many of the 55 adult females sampled used the lagoon for parturition on a
biennial cycle – reproducing roughly once every two years (Feldheim et al., 2001). It was
also reported that some females may use Bimini lagoon as a mating ground and other nearby
lagoons as a nursery.
Since 1995, Dr. Samuel Gruber and his colleagues of the BBFS, South Bimini, have been
carrying out an annual exhaustive tagging survey of the lemon shark population within the
Bimini lagoon. This survey, known as PIT tagging involves the use of tiny PIT (Passive
Integrated Transponder) tags to identify individual sharks in order to monitor trends in the
population from one year to another, such as population size and structure, survival rates,
growth rates etc. The tag, inserted under the skin of sharks, is a tiny glass encapsulated
electronic transponder that shows virtually no shed rate and absolutely no deleterious effects
on the sharks (URL: 2). Methods are described in detail in the methodology.
Figure 5. PIT tag. Note its size in comparison
to the English penny coin. When excited with
microwaves, it emits its number which can be
read by a specialist reading device. Photo: Alex
Brown.

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2.3 The North Sound and ‘Sharkland’
The capture of lemon sharks during the PIT tagging scheme takes part in two different
locations within the Bimini lagoon: the North Sound, and ‘Sharkland’ – as shown below.
The N. Sound is a semi-enclosed area of around 3km2
, affected by tidal movements through
a narrow area to the south and two creeks to the east. In addition to the two main water
bodies described earlier, the N. Sound acts as a third distinct body of water. Its very shallow
Figure 6a). Aerial photograph of
the North Sound, facing north.
Photo: Alex Brown, 2003.
Figure 6b). Aerial photograph of
‘Sharkland’, facing south. Photo:
Grant Johnson, 2003.
Figure 6c). Vertical aerial photograph of Bimini,
pre - 1990. Source: URL:1.
N
N
S
Paradise
Point

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topography (often partially exposed at low tide) restricts the tidal flow of water to and from
the N. Sound, causing a 1.5 to 2 hour retardation in tidal extremes compared to those of the
main lagoon. Turekian (1957) reported that this retardation causes a significant reduction in
water quality, including wide and rapid fluctuations in temperature and salinity. The N.
Sound appears to contain an almost closed population of young sharks with respect to
immigration and emigration (Gruber et al., 2001).
‘Sharkland’ is a more open environment; with no significant restriction or retardation of tidal
flow experienced – its tidal flow is very similar to that of the main lagoon. While the N.
Sound is almost completely fringed by mangroves, ‘Sharkland’ has mangroves only on its
east shore, and small islands; the western side being open to the main lagoon. Both sites have
a maximum depth of about 2m, however at low-water much of the area is exposed, and very
few places are more than 1m deep. It is obvious that productivity within the N. Sound is
lower than that of ‘Sharkland’ – with only sparse seagrass patches (figure 7) and dwarf
mangroves present compared to the dense seagrass beds (figure 8) and well developed
shoreline vegetation of ‘Sharkland’. Turtle grass, T. testudinum, the dominant species of
seagrass in the lagoon, has optimum growth conditions of 29 – 300
C water temperature and
33-360
/00 salinity, with rapid declines above 300
C and 500
/00 (Heffernan & Gibson, 1983).
Jacobsen, 1987, showed that water conditions within the N. Sound often exceeded 450
C and
40 - 480
/00 – putting the turtle grass present at the edge of its environmental tolerance. This
illustrates the fragile nature of the N. Sound ecosystem, which could easily collapse should
environmental conditions become even slightly more hostile than they already are. Better
tidal flow within ‘Sharkland’ allows sufficient exchange of water to prevent temperatures

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and salinities from ever becoming high enough to significantly impede seagrass and
mangrove development.
Figure 7. Photograph of less
dense seagrass bed in the N.
Sound. Main species is T.
testudinum. Photo: Steve Kessel,
2003.
Figure 8. Photograph of more
dense seagrass bed in Sharkland.
Main species is T. testudinum.
Grass shoots are longer than those
of the N. Sound. Photo: Steve
Kessel, 2003.

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2.4 Tourist Development on Bimini
‘Fishing and tourism began in 1920 and, along with its associated support activities, is
Bimini’s main economic activity’ (Lutz et al., 2002). ‘The International Game Fishing
Association (IGFA) was essentially born there’ (Kresge, 2003) and its surrounding waters
are home to many fishing tournaments from spring through autumn drawing sports fishermen
from around the world (URL:3). Diving, snorkelling, kayaking and marine nature excursions
are also important tourist activities.
The first large-scale land development involving dredge and fill operations began in the
1950s with the foreign-owned Sunshine Inn Resort and Port Royale subdivision (Gruber &
Parks, 2002). This hotel, marina and building lot project received very little business and
went through several bankruptcies, closures and rejuvenation attempts as it struggled to
make a profit (Gruber & Parks, 2002). This example is fairly typical of the success of large
developments on Bimini. Since then, a total of 4 completed/semi-completed attempts at
tourist developments have taken place on Bimini, most of which have been unsuccessful in
making a reasonable profit and have suffered financial difficulties. Of these developments,
only two remain active today: Bimini Big Game Club (BBGC) and Bimini Sands. BBGC
started out in the 1930s, and developed into the resort complex that it is today in 1963.
Although fairly successful in the long term, this resort comprising of marina, cottages, hotel
and restaurants has changed hands many times and is currently being renovated in an effort
to return a profit (Gruber & Parks, 2002).

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In 1990 South Bimini International Ltd began construction of Bimini Sands: 41 acres of
condominiums and marina on the west coast of S. Bimini. The opening of the marina basin
to the open ocean in 1995 lead to a succession of alterations to the natural geomorphological
processes taking place in the area. The most widely documented of these was the major
deposition of sand (known as shoaling) across the Bimini Harbour access channel,
immediately north of the Bimini Sands entrance jetties. Over time, the shoal grew larger,
making the channel shallower and narrower, thus impeding all but the smallest of vessels and
causing numerous yachts to run aground and suffer severe damage (Gruber & Parks, 2002).
Warnings were published throughout the yachting community (see: Lewis & Lewis, 2002)
resulting in a 40% decline in boating commerce in Alice Town, N. Bimini – financially
devastating for the local economy (Gruber & Parks, 2002). The Bahamas government
eventually contracted a dredging company to clear the channel, although the company
expected the shoaling to be a recurring problem. To date, only 60 of the proposed 216
condominium units have been constructed at the site, and less than 40 of these have been
sold (Gruber & Parks, 2002).
Figure 9. Bimini Sands, facing north. Note the
lack of buildings, even after 13 years of
development. Photo: Grant Johnson, 2003.

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Historically, the Bimini ecosystem has been virtually untouched by human disturbance
(Feldheim & Edrén, 2002). Its long tradition of sport fishing has accounted for limited take
on fish populations around the islands, whereas more recently it has become an important
ecotourism destination – offering dolphin encounters and diving excursions. However, over
the past few years the Bimini ecosystem, in particular the marine environment, has become
extremely threatened by the most recent large-scale development to plague the islands: RAV
Ltd’s Bimini Bay Resort.
2.5 RAV Ltd’s Bimini Bay Resort
The Bimini Bay site has a history of development dating back to the 1920s, and has changed
hands several times, although very little major construction has ever taken place there. In
1983, a subsidiary of American Express began construction of an elaborate resort complex,
completing some land clearing and dredging of the natural deep water channel on the lagoon
side of N. Bimini, but abandoned the project in 1986 (Gruber & Parks, 2002).
The 700 acre site encompassing all of western N. Bimini to the north, and half of east N.
Bimini (approx. two thirds of N. Bimini) was purchased in 1997 by RAV Bahamas Ltd., a
Miami based corporation, with the intention of building a mega-resort named Bimini Bay
Resort (BBR). Exact details of the project vary from source to source, but consistently
include 3 phases of development (see figure 10). Phase 1 comprises a 150 slip marina, a
hotel of 200 rooms, high density and single family residential buildings, resort centre with
shops and a 10,000 square foot casino – at a cost of US$100 million (Nassau Guardian, April
2003; Gruber & Parks, 2002). Phase 2 involves continued development of buildings to the

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northern tip of N. Bimini, while Phase 3 calls for extensive development on uninhabited,
pristine east N. Bimini, including an 18-hole golf course, and 5,000 ft airport (Gruber &
Parks, 2002). A 5 year ‘Heads of Agreement’ (HoA) was signed by RAV Bahamas Ltd. in
July 1997 calling for the completion of Phase 1 within this period.
The scale and details of the project have changed considerably over the 6 years of
development – within which very little construction has actually taken place. The project has
met considerable opposition from many people, including local residents, government
officials and members of the scientific community. Below is a chronological breakdown of
development activities taking place at the Bimini Bay site since 1997. The details of this
Figure 10. Drawing of the 3 development phases of RAV BBR, modified
from the 1997 RAV Environmental Impact Statement. Source: Gruber &
Parks, 2002.

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chronological summary were obtained largely from Gruber & Parks, 2002, and to a lesser
extent articles from the Bahamian press (The Bahamas Tribune: Feb 2001, Apr 2002; The
Nassau Guardian: Feb 2003, Apr 11/2003, Apr 15/2003) along with personal observations in
September 2003.
1997
 July: RAV signed HoA with Bahamas Government. A private EIS (environmental
impact statement) was carried out by Applied Technology and Management (ATM)
for RAV, although a co-author of the EIS later said that ‘it could hardly be
considered an authentic EIS.
 Mangroves and a Casuarina forest removed from a section of the western shore of
the N. Sound.
1998
 March: Prime Minister Hubert Ingraham inspects site and disallows any development
on the eastern side of the N. Sound. Bahamian officer assigned to monitor all RAV
work in the lagoon.
 Autumn 1998 – early 1999: little activity at site.
1999
 RAV investors withdraw financial support following Prime Minister’s decisions.
Project momentarily shut down.
 Late 1999: dredging of the main lagoon adjacent to the phase 1 site began. Dredged
material used for fill to raise land to required level for construction.
2000
 Dredging continued periodically.

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2001
 March: RAV begin intensive dredging scheme to meet fill requirements. Contrary to
EIS, HoA and verbal promises, no protective booms, silt barriers or sedimentation
traps are used. Extensive siltation produced throughout the lagoon and nearby coral
reefs.
 May: dredging continued on a 24 hour schedule. Massive siltation produced, along
with an access causeway blocking direct entry from Bailey town to fishing and
conching grounds. Causeway blocked tidal current along Bailey town and reduced
flow into the N. Sound. See figure 12.
 September: causeway now stretching almost 2 miles to the south. Further siltation.
 November: RAV dredging activity ceased.
2002
 February: dredging recommenced for several months.
 May: still no buildings erected on the site.
 July 31st
: HoA deadline for completion of Phase 1 not met.
Figure 11. Access causeway,
looking south. Source: URL:5

Alex Brown 2004
2003 – 2004
 Since mid-2002, dredging has ceased and very little activity has occurred at the site.
The only buildings present are several bare cinder block shells of condominium units.
No buildings are completed.
Figure 12. Diagram showing the current extent of development at the
BBR site. Note the blocking of the original channel and the anoxic dead
zones. Diagram by author.

Alex Brown 2004
3. METHODOLOGY

Alex Brown 2004
3.1 Notes
The principle methodology of this study involves the systematic analysis of 9 years of data
collected by the on-going PIT tagging scheme carried out annually by Dr. Samuel Gruber,
other scientists and volunteers of the BBFS. Although this study did not require any
additional individual data collection, the data displayed in the next chapter is not readily
available to the public. Extensive on site data compilation and analysis took place at the
BBFS between August and September 2003, in addition to thorough observation and
participation in field methods on a smaller scale, but identical to those described below.
3.2 PIT Tagging Methodology
This takes place annually, usually during the last week of May and the first week of June,
and involves the systematic fishing for lemon sharks with gill nets over a 7 day period,
repeated for the two locations within the lagoon: the N. Sound and Sharkland.
Figure 13. Map of N. Bimini. Red
bands indicate position of gill nets,
orange circles are main pens.
Source: URL:3.

Alex Brown 2004
3.3 Gill Netting
At dusk, three 180m long gill nets are set
perpendicular to the shore, with a pen
constructed from large mesh plastic fencing at
the offshore end of each net. An additional, much
larger pen of similar construction is located
nearby. The gill net is checked every 15min for
12 hours either by boat, snorkelling or walking -
depending on the state of the tide.
When a shark is caught, it is freed from the net and
walked to deeper water where it is transported in a
box (with water) by boat to the larger pen to be
‘worked up’ by a tagging crew.
3.3.1 Working up a shark:
Figure 16. Shark placed in the
tagging boat’s box and scanned
with PIT tag reader to determine
whether it is a recapture or not.
Photo: Eric Cheng
Figure 17. Length is measured.
Photo: Alex Brown
Figure 15. Shark caught in gill net.
Photo: Eric Cheng
Figure 14. Setting gill net. Photo: Eric
Cheng

Alex Brown 2004
The pen is checked regularly to ensure health of all captured sharks. Should sharks show
signs of ill health, they are either walked through the water or water is forced over them by
means of a small bilge pump until they are fully revived.
This process takes place in two 3 night stints, with one day rest in between. All captured
sharks are held in the pen (figure 22) and fed nightly, until their mass release at the end of
the 7 day period - ensuring that none are captured more than once. After at least one day off,
the process is then repeated at the other site, as described earlier. The methodology is
described in greater detail in Gruber et al., 2001.
Figure 18. The shark is weighed.
Photo: Eric Cheng
Figure 19. If no PIT tag is present,
one is inserted at the base of the
dorsal fin and its number is
recorded. Photo: Eric Cheng
Figure 20. A DNA sample is
punched out of the dorsal fin for
genetic analysis. Photo: Eric
Cheng
Figure 21. Shark transferred to
the holding pen. Photo: Eric
Cheng

Alex Brown 2004
3.4 Analysis of PIT data
From the large volumes of data collected during each annual tagging scheme, spreadsheets
can be compiled to show the following characteristics for each year:
 Total catch, recaptured sharks, mortalities during the tagging scheme, total length of
sharks (and average length), weight of sharks (including average weight).
From this, analysis of the changes in weight of sharks recaptured in consecutive years will
yield growth rates in the form kg/kg of shark/year. Additionally, the recapture rate of sharks
identified as newborn the previous year will allow the calculation of 1st
year mortality rates.
All of the above population characteristics will be displayed graphically for both the lagoon
as a whole, and in comparisons between the North Sound and Sharkland.
Figure 22. Sharks held in pen during PIT
tagging scheme. Photo: Eric Cheng
Figure 23. A juvenile lemon shark
leaves the pen. Photo: Eric Cheng

Alex Brown 2004
3.5 Statistics
The statistical programme MiniTab will be used to perform statistical analysis of the total
length, weight and growth rate of sharks for both sites, comparing periods pre and post-
dredging. The exact statistical test applied will depend upon the nature of the results.

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4. DATA ANALYSIS

Alex Brown 2004
4.1 Notes
From now on, the N. Sound and Sharkland are referred to as NS and SL respectively. The
‘whole lagoon’ refers to both these areas combined, its data either an average or total of NS
and SL values. Newborn sharks, for the purpose of this study, were those less than 70.0 cm
total length and/or with an open umbilical scar, with no previous PIT tag. For all datasets,
averages are provided for the two periods: prior to any dredging activity (pre-dredging,
1995-1999); and since dredging has commenced to the present (post-dredging, 2000-2003).
All averages referred to are the mean. All tables and charts are by author.
4.2 Catch Data
Year Total Catch Recaptured Newborn
NS SL
Whole
lagoon NS SL
Whole
lagoon NS SL
Whole
lagoon
1995 92 91 183 n/a 31 32 63
1996 63 75 138 24 27 51 29 31 60
1997 95 95 190 40 26 66 53 57 110
1998 77 95 172 37 42 79 32 49 81
1999 78 105 183 32 34 66 37 63 100
2000 67 136 203 35 48 83 19 71 90
2001 58 87 145 19 44 63 36 34 70
2002 64 89 153 27 37 64 36 41 77
2003 67 107 174 31 46 77 36 47 83
Total 661 880 1541 245 304 549 309 425 734
1995 - 1999 81 92 173 33 32 66 36 46 83
2000 - 2003 64 105 169 28 44 72 32 48 80
Table 1. PIT tagging catch data. Figures shown are number of sharks,
including the total catch per year, the number of recaptures from previous
years, and the number of newborn sharks caught. This is also broken
down into figures for NS and SL in addition to the whole lagoon. Figures
in green are averages for the years 1995 through 1999, while those in red
are averages for 2000 – 2003.

Alex Brown 2004
Table 2. Newborn sharks: odd
and even years breakdown.
Table 1 summarizes the numbers and general characteristics of sharks caught during the PIT
tagging scheme between the years 1995 and 2003. The figures show the total number of
sharks caught to be greater in SL than in the NS. This difference was far greater during the
post-dredging period than it was pre-dredging. The NS experienced its lowest ever catch of
58 sharks in 2001, while SL’s lowest catch was in 1996.
Recaptured sharks are those caught which already contain a PIT tag, and their abundance
gives a reliable estimate of the number of sharks surviving from previous years (Gruber et
al., 2002). Numbers were, on average, 6 greater in the post-dredging period, apart from in
the NS where they were 5 less – plummeting to a record low of just 19 recaptures in 2001.
As the tagging scheme commenced in 1995, no recaptures were recorded that year.
Despite some considerable year to year fluctuations, the average number of newborn sharks
pre and post-dredging was very similar, with a greatest difference of -4 sharks in the later
period in the NS. Assuming that the same population of adult females return biennially to
pup, it is worth breaking this data down into odd and even years to compare the breeding
success of the two populations.
Newborn
NS SL Average
Odd
years 37 47 42
Even
years 29 48 39

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Table 2 shows the population giving birth in the NS during odd years to produce an average
8 pups more than those of even years. SL shows little difference. The year 2000 saw the
lowest recorded number of newborn sharks at just 19 in the NS – 34% less than the average
for that population of adult females.
Chart 1. Total Catch, recaptured & newborn sharks 1995 - 2003
0
20
40
60
80
100
120
140
1995 1996 1997 1998 1999 2000 2001 2002 2003
Year
No.ofSharks
NS:Total Catch NS:Recaptured NS:Newborn
SL:Total Catch SL:Recaptured SL:Newborn
Chart 1 visually represents the data shown in table 1. Note how the values for the two areas
(NS and SL) are very similar for 1995 and 1996, but start to show greater variation in the
years following this – most notably in 2000. Both datasets then gradually become similar
again in 2002 and 2003, with the exception of total catch. Total catch in NS shows a gradual
decline between 1999 and 2001 – when dredging activity was at its most intense.

Alex Brown 2004
4.3 Size Characteristics
NS SL Whole Lagoon
Year TL (cm) WT (kg) TL (cm) WT (kg) TL (cm) WT (kg)
1995 65.8 1.47 68.4 1.73 67.1 1.60
1996 69.4 1.75 71.3 1.97 70.4 1.86
1997 72.2 2.00 70.9 2.00 71.6 2.00
1998 71.9 1.97 71.0 2.03 71.5 2.00
1999 69.2 1.84 70.7 1.94 70 1.89
2000 71.8 1.94 68.8 1.78 70.3 1.86
2001 65.9 1.53 68.5 1.71 67.2 1.62
2002 65.8 1.49 68.6 1.70 67.2 1.60
2003 67.0 1.56 72.1 2.02 69.6 1.79
1995 - 2003 68.8 1.73 70.0 1.88 69.4 1.81
1995 - 1999 69.7 1.81 70.5 1.93 70.1 1.87
2000 - 2003 67.6 1.63 69.5 1.80 68.6 1.72
Over the 9 year period, the sharks caught in SL were slightly larger than those caught in NS
– both in terms of total length and weight. However, these differences were small: just 1.2
cm and 0.12 kg. Both study sites showed a reduction in the average length and weight of
sharks between the pre and post dredging periods. This reduction was more noticeable in NS,
with post-dredging sharks averaging 2.1cm and 0.18kg less than pre-dredging sharks,
compared to 1.0cm and 0.13kg less in SL.
The non-parametric Kruskal-Wallace Test has been applied to the data in table 3, comparing
total length and weight values between pre and post-dredging periods for both sites. A full
description of the results of these tests is available in A.3, appendix. The tests confirmed the
reduction in total length post-dredging to be significant in NS, but not significant in SL. The
Table 3. Total length (TL) and weight (WT) averages of sharks caught. Figures for
individual years within each site are derived from a randomly selected sample of
50 sharks from the total caught for that particular year. The whole lagoon figure is
subsequently based on a sample of 100. The 1995 – 2003 data is an average of the
values for each year. The two periodic datasets (’95-’99;’00-’03) are averages of
the figures for their constituting years.

Alex Brown 2004
reduction in weight is confirmed significant for both NS and SL. All reductions deemed
significant are at or above the 95% level of significance. For the lagoon as a whole, the post-
dredging reduction in total length is significant to the 95% level, while the weight reduction
can be said to be very highly significant at the 99% level.
4.4 Growth Rates
Growth rates were calculated by measuring the weight of recaptured sharks compared to
their weight the previous year.
e.g. • 1995 WT = 1.5 kg, 1996 WT = 2.0 kg
• 2.0 – 1.5 = 0.5kg weight gain.
• 0.5/1.5 = 0.333kg/kg of shark/year
For simplicity, growth rates were only calculated for sharks recaptured in consecutive years.
Several limitations arose from this method as some years yielded very few recaptured sharks
(i.e. 19 in NS, 2001). Also, each year a certain number of recaptured sharks were not fully
‘worked up’, usually due to bad condition – further limiting the number of growth rate values
that could be calculated. Consequently, the total number of growth rate values for sharks for
the separate study sites varied immensely from 40 (SL, 2001) to just 12 (NS, 2001) values.
Thus, in order to maintain a constant sample size, a maximum of 12 values from each site
per year could be taken to form an average growth rate. 12 samples from each site for each
year were randomly selected (with the exception of NS, 2001) and averaged to give a year by
year breakdown of growth rates within the NS, SL and whole lagoon. The results of this
method are shown overleaf in table 4.

Alex Brown 2004
The values for growth rates in table 4 should not be regarded as reliable due to the very small
sample size. More reliable average growth rates can be calculated for the two separate study
sites, and combined whole lagoon, if we once again split the data into two periods: pre and
post-dredging. Two different sampling methods can be used to create these averages.
1. R50. All individual growth rate values are assigned to their corresponding fields: NS
pre-dredging; NS post dredging; SL pre-dredging; SL post-dredging. 50 values per
field are then randomly selected, the averages of which then form the final growth
rate values for each field.
2. R48. As with the results in table 4, 12 samples are selected from each site per year.
These are then combined into the fields described above and averaged. This ensures
an equal number of values are taken from each year.
Growth Rate (kg/kg of shark/year)
Year NS SL Average
1995 - 1996 0.667 0.576 0.622
1996 - 1997 0.234 0.486 0.360
1997 - 1998 0.386 0.514 0.450
1998 - 1999 0.713 0.508 0.611
1999 - 2000 0.354 0.332 0.343
2000 - 2001 0.414 0.436 0.425
2001 - 2002 0.296 0.393 0.345
2002 - 2003 0.430 0.517 0.474
Table 4. Average growth rates per year in NS, SL and whole
lagoon (average of NS and SL).

Alex Brown 2004
Table 5 displays the results of the R50 and R48 sampling methods, providing reliable
estimates of trends in growth rates for the periods pre and post-dredging. The data shows a
reduction in average growth rates for all fields, ranging from 16.33% (NS, R50) to 25.20%
(NS, R48). According to R50, SL has experienced a greater reduction in growth rates than NS;
however the opposite is true of R48. Considering the somewhat restricted nature of the
sample size per year in R48, conclusions should not be based upon its values. It does,
however, serve the purpose of verifying an overall reduction in growth rates within the
whole lagoon.
Over the 9 years of sampling, the growth rates in NS were 31.81% less than those in SL, a
figure fairly consistent between the two sub-periods (R50). Post-dredging, juvenile lemon
sharks in the Bimini lagoon were, on average, growing at a rate almost 1/5 less than they
were pre-dredging (R50).
Again, the Kruskal-Wallis test has been applied to the data to determine if the post-dredging
reduction in growth rate could be described as significant. For the purposes of this test, all
growth rate values available for all years were used. It suggested that the reduction in NS
Growth Rate (kg/kg of shark/year)
Method Period NS SL Whole lagoon
R50
1995 - 1999 0.349 0.522 0.436
2000 - 2003 0.292 0.418 0.355
% Change -16.33 -19.92 -18.58
R48
1995 - 1999 0.500 0.521 0.510
2000 - 2003 0.374 0.419 0.396
% Change -25.20 -19.58 -22.35
Table 5. Average growth rates of sharks in the Bimini lagoon, using R50 and
R48 sampling methods.

Alex Brown 2004
cannot be considered significant, most likely because of the limited number of values
available for the post dredging period. In SL, however, the reduction is found to be
significant to above the 95% level. For the lagoon as a whole, the reduction is significant to
the 95% level.
4.5 First year survival rates
This is calculated as the percentage of newborn sharks recaptured the following year.
Newborn sharks which are not recaptured the following year are rarely ever seen again and
are assumed dead. On rare occasions, some newborn sharks were not recaptured the
following year, but were recaptured 1 or 2 years after that. In those situations the sharks were
considered to have survived to age 1, despite not being caught that particular year. This
places a question mark over the accuracy of 1st
year survival of the 2002 newborn sharks, as
some of the sharks assumed dead in 2003 may be recaptured in the future. However, should
this occur, it would be likely to only have minimal effect on the current value.
Survival rate (%)
Year NS SL Whole lagoon
1995 - 1996 80.0 53.1 61.9
1996 - 1997 58.6 35.5 46.7
1997 - 1998 30.2 56.1 43.6
1998 - 1999 53.1 34.7 42.0
1999 - 2000 46.0 38.1 41.0
2000 - 2001 21.1 35.2 32.2
2001 - 2002 36.1 38.2 37.1
2002 - 2003 25.0 58.5 42.9
1995 - 2003 43.8 43.7 43.4
1995 - 1999 55.5 44.9 48.6
2000 - 2003 32.1 42.5 38.3
Table 6. First year survival rates of sharks.

Alex Brown 2004
Over the 9 year period, first year survival rates varied immensely from a high of 80.0% of
newborn sharks between 1995-1996, NS, to just 21.1% between 2000-2001, NS. This value
of just 21.1% saw the 2001 recapture of just 1 shark newborn in 2000, 3 more were
recaptured in 2002. The average rate for this period was almost identical in both NS and SL
at ~43%. When the data is split between pre and post-dredging periods however, there is a
clear trend of reducing survival rates post-dredging. Although this reduction is just 2.4 % in
SL, it is a considerably larger 23.4% in NS – contributing to a reduction in first year survival
rates of 10.3% within the whole lagoon. Chart 2, below, graphically illustrates these trends.
Chart 2. First year survival rates of sharks: Pre, and Post Dredging
0.0
10.0
20.0
30.0
40.0
50.0
60.0
NS SL Whole lagoon
Habitat
Survivalrate%
1995 -1999 2000 - 2003

Alex Brown 2004
4.6 Mortalities during PIT tagging scheme
This is an expression of the number of captured sharks which died at some stage during the
PIT tagging scheme. Death of captured sharks can be due of negligence on the part of the
people carrying out the survey, however hours of training and expertise generally eliminates
deaths of sharks by these causes. The level of mortality is more an indication of general
health of the captured sharks, rather than an assessment of the field skills of the people
involved.
Table 7 shows a marked increase in mortality post-dredging in the NS, while a slight
reduction was observed for SL. Of most significance are the mortalities of 10.5% in the NS,
2000, and 14.9% in SL, 2001. These were the highest ever recorded mortalities during PIT
tagging, and co-inside with the most intense dredging activities.
% Mortalities during PIT
Year NS SL
Whole
Lagoon
1995 5.4 9.9 7.7
1996 4.8 8.0 6.4
1997 1.1 5.3 3.2
1998 3.9 9.5 6.7
1999 0.0 1.9 1.0
2000 10.5 4.4 7.5
2001 5.2 14.9 10.1
2002 7.8 1.1 4.5
2003 1.5 4.7 3.1
1995-1999 3.0 6.9 5
2000-2003 6.3 6.3 6.3
Table 7. % mortalities of sharks captured during the
PIT tagging scheme. Figures are derived from the
number of deaths as a % of the total catch for that
area/year.

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5. DISCUSSION

Alex Brown 2004
5.1 Summary of BBR activities combined with identified trends
Date BBR Activity Evidence of impacts
(From Gruber & Parks,
2002, unless stated
otherwise)
Juvenile shark
population
characteristics
(Data by author)
1995 –
June 1999
No dredging.
No activity other than
removal of mangroves
and a Casuarina forest
from western shore of
NS in 1997.
Removal of plant root
systems led to severe
erosion along NW
beaches. Storm waves
breached eroded dunes
and spilled into NS.
Growth rates average
0.436kg/kg/year (0.349,
NS; 0.522, SL).
1st
year survival rates
average 48.6% (55.5%,
NS; 44.9%, SL).
Late 1999 Dredging adjacent to
phase 1 site began.
2000 Dredging continued
periodically.
NS sharks captured
during PIT tagging
(May/June) nearly all
showed signs of extreme
neurological and
physiological stress.
(Gruber et al., 2002).
Record low newborn
sharks = 19, NS.
Shark TL and WT
reduces in SL.
Record low growth rate
of 0.343 kg/kg/year
for1999-2000 in whole
lagoon. Also record low
in SL.
1st
year survival rate
(1999-2000) falls by
7.1% in NS.
% mortality during PIT at
record high of 10.5%, in
the NS.
2001 March: Intensive
dredging scheme
commences.
May: dredging
continues on 24hr
cycle.
Causeway erected
parallel to natural
channel stretching 2
miles south.
November: dredging
ceased.
SL sharks captured
during PIT tagging
(May/June) nearly all
showed signs of extreme
neurological and
physiological stress.
Lack of protective
booms, silt barriers or
sedimentation traps led to
extensive siltation
throughout lagoon …
Total catch, recaptured
and newborn reduced
throughout lagoon. Only
19 recaptures in NS.
Shark TL and WT
reduced throughout
lagoon, particularly in
NS.
1st
year survival rate
(2000-2001) falls
throughout lagoon; …

Alex Brown 2004
Date BBR Activity Evidence of impacts
(From Gruber & Parks,
2002, unless stated
otherwise)
Juvenile shark
population
characteristics
(Data by author)
2001 Ctd. ...and nearby coral reefs
up to 5 miles south of
Bimini. Causeway
significantly reduced
tidal flow into NS, and
cofferdams created
anoxic and azoic zones
killing off fish stocks.
Dive operators complain
about poor visibility,
unhealthy coral, algal
blooms and few fish.
…falling to just 21.1% in
NS.
Growth rates increase,
but data unreliable.
% mortality during PIT at
record high of 14.9%, in
SL.
2002 February: dredging
recommenced for
several months.
Locals complain about
disappearance of conchs,
sea horses, sea
cucumbers and shrimp
from various locations
within the lagoon where
they were once common.
Fishermen note that
lagoon waters now
become muddy during
even moderate winds (20
knot).
Shark TL and WT reduce
slightly in NS.
Growth rates plummet
throughout lagoon.
1st
year survival rate
slightly increases.
2003 -
Present
No dredging.
No other significant
activity.
Total catch, recaptures
and newborn all increase.
Shark TL and WT
significantly increase
throughout lagoon, as do
growth rates.
1st
year survival rate
increases overall, but
drops again to just 25.0%
in NS.
Table 8. Summary of BBR activities combined with identified trends in lemon shark
population and other evidence of ecological impacts.

Alex Brown 2004
5.2 Explanation of results
The analysis of data displayed in the previous chapter has shown several properties of the
juvenile lemon shark population of the Bimini lagoon to change considerably both from one
year to the next, and significantly between the pre (1995-1999) and post (2000-2003)
dredging periods. These changes have often been of their greatest detrimental magnitude
during, or soon after the periods of most intense, extensive dredging activities associated
with the BBR development. In addition to this, large numbers of sharks captured during
periods of intense dredging showed severe levels of physiological and neurological stress,
leading to extremely high levels of mortality during PIT tagging - not observed in any other
year of the survey. The stress first occurred in the NS, and then one year later in SL in
tandem with the movement of dredging activities further south, closer to SL. Table 8
illustrates these correlations.
Since dredging began in late 1999, the growth rate, first year survival rate and average size
of juvenile lemon sharks has fallen throughout the lagoon. Therefore, with regards to the
whole lagoon, all null hypotheses can be rejected – confirming that:
- There has been a significant reduction in total length, weight and growth rate of
sharks between pre and post-dredging periods.
This trend is also true for the majority of values within the separate study site of NS and SL.
The only exceptions are total length in SL, and growth rate in NS – for which the null
hypothesis must be accepted, indicating no significant difference in values between pre and
post-dredging periods.

Alex Brown 2004
Total length and weight are obviously linked to growth rate, as the weight of recaptured
sharks should correspondingly fluctuate in accordance with their growth rate. With regard to
newborn sharks, for which no growth rate data is immediately available, total length and
weight is a good indicator of their initial response to the environment. Total length of
newborn sharks would be expected to increase regardless of the environmental conditions
due to a natural, genetically governed growth response. Weight, however, will only increase
if the newborn sharks are able to quickly and efficiently find food. The weight of individual
sharks can be increased dramatically if they have a full stomach, so average weight values
also serve as a good indicator of the number of sharks which have recently eaten and are
successfully catching prey – essential for survival.
The NS appears to be a much less productive and more fragile environment for the juvenile
lemon sharks than SL. It supports a much smaller population of sharks, with lower growth
rates and sizes than the sharks captured in SL. Although the post-dredging reduction in
growth rates appears to be of a lower magnitude than the reduction in SL, the reliability of
this data is somewhat questionable. Post-dredging, the NS showed a massive reduction in 1st
year survival rates – a far greater reduction than that experienced by SL.
In 2001, when dredging was at its most intense, the population of juvenile lemon sharks had
fallen to just over half the number of individuals present 4 years earlier in 1997. Clearly the
population of the NS would rapidly cease to exist should habitat destruction and dredging
occur on a scale such as that proposed for future BBR development.

Alex Brown 2004
5.3 Assumptions
There are several assumptions made in this study. One of the most significant is that the two
populations of lemon sharks in the NS and SL are closed, with no immigration or emigration
of individuals out of the sample sites. The study also assumes only natural mortality within
the lagoon – no account of fishing is taken, although this is not believed to be significant.
There are other considerations to be made regarding the limitations of the data in this study,
these are discussed in chapter 6.2.
5.4 Direct effects on the lemon sharks
5.4.1 Dredging
As the observed impacts have occurred relatively soon after periods of dredging activity, it is
most likely that the lemon sharks have so far been almost exclusively affected by direct,
immediate pathways. Direct effects would have included a reduction in water quality. The
reduced clarity of the water due to suspended sediment will have impeded the sharks’ vision
– a crucial component to their feeding strategy. The disruption to tidal flows, particularly in
the NS, raised the temperature and salinity of water considerably. Although lemon sharks’
tolerance limit to these variables is not known, should the temperature and salinity continue
to rise, their growth and survival is likely to fall way below optimum.
Elevated levels of sediment, salinity and temperature rapidly increased the hostility of the
marine environment. It is hypothesised that the stress which this placed on the lemon sharks

Alex Brown 2004
while in their vulnerable first few years of life contributed largely to their reduced growth, 1st
year survival and signs of severe neurological and physiological stress that were experienced
during the periods of dredging within the lagoon.
5.4.2 Habitat Destruction
The removal of mangroves by clearing, draining and filling that has occurred around the
previously pristine marshes of Paradise Point has destroyed part of the juvenile sharks’
habitat. Although this area is only a small percentage of the available habitat for this species,
the sharks’ home ranges have been shown to be very small, showing strong attachment to
their birth site during early life (Morrissey & Gruber, 1993). Thus, the destruction of a
hundred metres or so of mangrove coastline may remove the entire habitat of one or more
juvenile lemon sharks. The loss of habitat forces the sharks to live in greater density –
increasing the competition for space, food and shelter.
Although the apex predator in the ecosystem, juvenile lemon sharks are themselves preyed
upon by larger sharks including sub-adult lemon sharks; barracuda, Sphyraena barracuda;
and bull sharks, Carcharhinus leucas (Feldheim & Edren, 2002). The dense underwater root
systems provide shelter for the young sharks, along with juveniles of many other fish
species. Therefore removal and degradation of the mangrove habitat will expose juvenile
lemon sharks to increased predation. Feldheim et al. (2002) reported several sub-adults
swimming excitedly around a pregnant female on her way to the mangroves, hypothesising
that the sub-adults were waiting to feed on newborn pups. ‘Thus, survivorship of a female’s
pups may hinge on her ability to reach the mangroves safely where newborns are provided

Alex Brown 2004
immediate protection from predators’ (Feldheim & Edren, 2002). It is highly likely that the
destruction of mangroves and interference with pregnant females’ passage to the mangroves
has contributed to the observed reduction in first year survival of lemon sharks since
development activity commenced.
5.5 Indirect effects on the lemon sharks
Since lemon sharks are the top predators in the Bimini food web, they serve as an effective
biological indicator of conditions lower in the food chain (Gruber et al., 2002). This enables
us to estimate the overall health of the lagoon ecosystem despite the lack of quantitative data
on trends in marine populations other than those of the lemon sharks. Changes in the state of
S
Figure 24. Aerial photo of the destruction at the BBR site, as of late 2001. Looking south.
Paradise point is just off the bottom of the picture. Source: Gruber & Parks, 2002.

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trophic levels below that of the lemon shark, be they direct prey species or even primary
producers, will have knock-on effects on these top predators. ‘Any general disruption of the
ecosystem will manifest most prominently in the growth or population dynamics of the
lemon sharks’ (Gruber et al., 2002).
The main indirect effect on the lemon sharks involves the application of the above direct
impacts to all other marine organisms beneath the lemon sharks in the food web. They too
will suffer loss of habitats, exposure to predators and increased stress from reduced water
quality and reduced abundance of food/prey. Their increased exposure to predators will
initially benefit the lemon sharks, as they are the main predator in the ecosystem. However,
the populations of prey species will quickly crash – limited the food available for growing
juvenile lemon sharks, thus reducing their growth rate and corresponding size.
These indirect effects have a more complex pathway between the impacting activity and
lemon shark, yielding a greater ‘lag-time’ than previously discussed direct effects.
Consequently, the full effects of the dredging and habitat destruction on the lemon sharks
and ecosystem as a whole may not be observed for some time yet.
5.6 The importance of sharks to the marine environment
Survival of lemon shark populations depends on the continual recruitment of juveniles from
the nursery into the breeding population; ‘if the nursery fails to produce future breeding
generations, the population can be expected to rapidly decline’ (Gruber et al., 2002). In a
broader sense, the Bimini lagoon is considered the only viable nursery on the western edge

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of the Great Bahamas Bank for many species of coral reef fishes, of which the lemon shark is
a key species (Feldhiem & Edren, 2002). Therefore the destruction of this nursery ground
would effectively remove a top predator from the many ecosystems of the western Great
Bahamas Bank. As with the removal of any top predator, a devastating top-down effect will
take place. Stevens et al. (2000) used computer models to predict the likely outcome of
removing sharks from several different ecosystems. Effects were varied but usually resulted
in a population boom of the shark’s main prey items, which in turn caused a huge decline in
numbers of this booming population’s main prey items. Other cases saw the removal of
sharks releasing certain species from their main or only predator in the ecosystem – whose
population consequently increased considerably. Ironically, the populations which suffer the
most are often those of most economic value to humans (Stevens et al., 2000).
5.7 Effects of dredging and filling on the whole ecosystem
The dredging and filling to date has led to habitat destruction, disruption of tidal flow and
massive sedimentation within the lagoon and surrounding reefs. According to the EIS of the
BBR development, dredging will create deep channels which, “…will create a platform for
different habitat types”, “create …improved flushing”, “provide deep water refuges to
existing biota during times of extreme warm or cold periods”, and, “provide habitat
pathways to the shallow Sound (NS) with more diverse marine life than currently exists”. It
is not quite clear what the scientific theory is behind this hypothesis, but there is an excess of
literature published documenting the negative effects of dredging on ecosystems (see: Sarda
et al., 2000; Riegel & Piller, 2000). To date, dredging has directly removed only a relatively
small area of natural habitat, however the dredged material used for fill has covered

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considerable areas of previously pristine forest and mangrove habitat. Excavating and filling
the extensive mangrove swamp east of Paradise Point has completely destroyed that habitat,
causing the extinction of all resident species in the sections that were walled off and blocked
The disruption of tidal flow, particularly to the NS has been devastating to marine
communities within that area. The causeway parallel to the natural Alicetown channel in
2001 reduced the already restricted tidal flow within the lagoon, increasing the tidal
residence time of water in NS by 90 minutes (Gruber & Parks, 2002). See A.2, appendix, for
satellite imagery of the causeway. Lugo & Snedaker (1974) showed mangroves to rely upon
adequate tidal flow for survival and production. High flow is essential for nutrient and
oxygen supply.
The regular influx of oxygen and nutrients is also essential for the development of seagrass
beds within the NS. It has already been seen that T. testudinum suffers greatly reduced
survival at salinities above 500/00 and death at 600/00 (Herffernan & Gibson, 1983). Prior to
development at the BBR site, NS salinities often reached 480/00 – a figure undoubtedly
exceeded during the period of most reduced flow. The additional residence time of water
within the NS will allow its temperature and salinity to increase to levels above those of the
tolerable limits of many organisms present. Blue crabs (Portunidae) are an example of such,
exhibiting reduced growth above 450/00 salinity, and 50% mortality at 660/00 (Guerin &
Stickle, 1992). These crabs have an extremely high biomass in the NS and are a food source
for many fish species within this habitat, including juvenile lemon sharks (Gruber et al.,
2002).

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The mobilisation of sediments into the water column caused by dredging has probably been
the most significant impact so far. When sediments are resuspended they can release
dangerous concentrations of nutrients and pollutants that have been deposited within the sea
floor sediments over many years (BEST, 2002). Unfortunately, no relevant geochemical
analysis of the suspended sediments took place at the time of dredging. Thorough
geochemical analysis of sea floor sediments in areas of proposed further dredging would
give an indication of likely changes to the water column should this further dredging take
place.
Figure 25. Aerial photograph, 30/4/02, showing sediment plume
extending south along Alicetown channel from dredging site at
BBR in the north. Note the extent of the causeway in the north.
Source: Gruber & Parks, 2002.
Causeway
Sediment Plume

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Within the Bimini lagoon, sediments clouded up the water and severely impeded light
penetration. This inhibited photosynthesis within the seagrass and other photosynthetic
organisms - reducing primary production. Although water clarity has improved since
dredging ceased in 2002, the settling out of sediment onto the lagoon floor has coated much
of the vegetation with layers of silt – reducing both photosynthesis and gas exchange.
5.8 The future of Bimini Bay Resort
Figures 26 and 27 show the current state of development at the BBR site, as no major
developments have occurred since those photographs were taken. According to the lawyer of
RAV Bahamas Ltd.’s CEO, Gerado Capo, ‘the magnitude of the investment has been
substantially reduced, and a down-sized project is now expecting to get underway by
December of 2004’ (Nassau Guardian, 15th
April, 2003).
Figures 26 & 27 . The BBR
site, summer 2003. No
buildings yet completed.
Fig.12: Grant Johnson
fig.13:URL:5.
Fig. 26
Fig. 27

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Figure 28 shows that the supposedly down-sized project due for commencement in
December 2004 involves development along all shores of the NS, further mangrove removal
on west N. Bimini, and extensive development on pristine, uninhabited east N. Bimini,
pictured overleaf.
Figure 28. Map of the latest proposed BBR development. All
land indicated as ‘BBR development’ and ‘dredged lagoon
floor’ has been transformed from a photograph of a land use
plan displayed by Gerado Capo at a meeting with prospective
investors of the revised project in July 2003. Adapted from
photograph by William C. Parks.

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Even more worrying is the extent of dredging, shown in figure 28 to include the dredging of
a boat channel around the entire shore of the NS. This will completely destroy the submerged
prop-root environment that the fringing mangroves provide – rendering the NS completely
ineffective as a nursery ground for the juvenile lemon sharks, and many other marine
species. However, the sedimentation and disturbance generated by the dredging would be so
severe that the ecosystem and surrounding coral reefs would effectively be ‘killed’ before the
loss of nursery grounds even became an issue.
The fishing and diving industries of Bimini would be destroyed as the lagoon and local reef
species disappear, and sedimentation destroys the visibility of Bimini’s famously clear
waters. Local fishermen have already reported serious declines in conch, lobster and
crawfish populations (Nassau Guardian, 7th
February, 2003). Further dredging would lead to
the extinction of existing populations – removing an important source of local produce.
Figure 29. The uninhabited mangrove swamps of east N. Bimini. Photo:
Grant Johnson.

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The extent of government intervention to protect the Bimini environment has so far been far
from sufficient. The deeply flawed EIS provided by RAV Bahamas Ltd fails to recognise the
documented presence of 11 marine and land species (including lemon shark) listed as
threatened or endangered by the IUCN Red list and/or National Marine Fisheries Service on
the project property. The proposed establishment of a No Take Marine Protected Area
(NTMPA), encompassing much of N. Bimini, would have provided good protection of much
of RAV Bahamas Ltd’s land. However, this project was shelved in 2001 due to lack of
financial support (Gruber & Parks, 2002). See figure A4, appendix, for the proposed
boundaries of this NTMPA.
In an article in The Nassau Guardian, 15th
April, 2003; Keod Smith, Ambassador for the
Environment, said that ‘what should have been done to keep from causing the damage that
was done obviously should have been done three years or more ago’ and suggests that the
government has put a stop to the BBR project pending the receipt of a more detailed
environmental impact assessment. Mr Grimes, Gerado Capo’s lawyer, however denied any
stoppage to the project, and confirmed that development would continue as soon as approval
for certain plans was received from the Ministry of Works. It is not clear when, or if the
project will progress further as so many deadlines have already failed to be met. It has been
suggested that some major development schemes such as this are nothing more than money-
laundering ventures between foreign companies (Sealey, 2002). ‘The answer to all of this is
clearly close government monitoring at all stages of a project, and sadly this has not been
adequate at any time in the recent past’ (Sealey, 2002). Throughout the Bahamas there are
numerous projects failed, in progress, and planned, but information on them is scattered and

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hard to pin down (personal communication, Sealey to Brown). We have already seen the
majority of similar such attempts at tourist development on Bimini fail, so it is unlikely that
this project will be successful enough to generate sufficient profit to stay in operation for
more than a few years.
Scientists working with the BBFS, along with other interested parties, have been
campaigning to government departments with great determination throughout the course of
the project; advising them on the impacts the project has caused so far, and the likely impacts
of continued development. This lead to the publication of a special issue of the Bahamas
Journal of Science (9(2)) in May 2002 devoted entirely to the ecology and human activities
in Bimini. This issue was done partly because no projects of this type were ever studied or
recorded in the past (personal communication, Sealey to Brown, 2003). None of this would
have been necessary should RAV Bahamas Ltd have carried out an accurate, independent
EIS of the BBR site.
There is, however, some hope for the prevention of further damage to the Bimini ecosystem.
In late 2003, Dr. L.S. Marshall, consultant and science advisor to the Prime Minister, stated
that he had been ‘working closely with the project developers, the BEST Commission, the
Department of Fisheries, the Ministry of Health and Environmental Services, the Ministry
of Financial Services and Investments and the Ministry of Works to "fix" the Bimini Bay
project to all environmental extents possible’ (personal communication, Marshall to Gruber).
In the same communication he explained that the original EIS consulting firm, ATM, has
been employed to provide additional and critically needed environmental assessments of the
project, and a third independent consulting firm is being considered to oversee

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environmental assessments and monitoring for the project. He hopes that this will ‘make the
Bimini Bay project as environmentally friendly as possible’. The full communication is
contained in A.5, appendix.
Further hope comes from the data acquired during the 2003 PIT tagging scheme. Several
months after the dredging activity ceased, the populations of both areas were showing some
signs of recovery with increasing total catch, recaptures and newborn sharks. Growth rates
between 2002 and 2003 also showed an increase, as did the average survival rate for the
whole lagoon. This suggests that the effects observed in previous years to the lemon shark
populations may have only been temporary, and the populations may show full recovery in a
few years time. However, there are still the less direct, more delayed impacts to consider
which were described in chapters 5.4 and 5.6, not to mention the future drop in newborn
sharks when the juveniles impacted between 2000 and 2003 reach reproductive maturity.

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6. STUDY CRITIQUE

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6.1 Achievement of aims and objectives
The primary aim and objectives have been satisfied with good levels of success. The
available data has been rigorously analysed in every way intended by the objectives, and a
series of trends have been identified, most of which correlate with the development activities
associated with the BBR development. Several of these trends were shown to be statistically
significant, however the use of statistical analysis was somewhat limited by the small
quantity of data for certain variables in particular years. A more reliable breakdown of year
to year growth rates would have been useful. The Kruskal-Wallace test used is not the most
frequent choice of statisticians, however unlike its parametric counterparts, it does not make
such strict assumptions and is frequently more suitable for processing biological data
(Fowler et al., 1998).
The secondary aims were also completed to a good level, although the investigation into
impacts on marine communities other than juvenile lemon sharks was only described to a
low level of detail. This is mostly due to the lack of long term study on organisms other than
the lemon sharks within the Bimini lagoon. Examining the impacts on marine organisms
other than the lemon sharks could easily form another study all on its own.
6.2 Limitations of Study
A whole host of limitations arise from this study, affecting the validity of the results and any
possible conclusions. The PIT tagging scheme was developed predominantly as a method for
observing breeding biology and early life history of lemon sharks, although the extent of the

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data acquired provides the opportunity for many other studies to take place. The
appropriateness of the data for what is essentially an environmental impact study such as this
is something that has to be seriously considered.
An effective and well recognised method of monitoring environmental impacts is through an
impact assessment monitoring strategy known as Before After Control Impact (BACI)
design. In such a technique, samples or observations are taken from both Impact and Control
locations during both Before and After periods. ‘Only when all these data are in hand can we
logically distinguish natural changes at the impact location from those caused by specific
human activities’ (Downes et al., 2002). The main problem which this particular study faces
is the absence of a control location, as data from both before and after human activities is
available. Prior to data analysis, the use of SL as a control location was considered, due to its
more productive, less fragile nature as an ecosystem compared to that of the NS (originally
intended as the impact location). This is why all data in chapter 4 is separated into values for
SL and NS, in addition to the whole lagoon. However, SL is not sufficiently detached from
both the BBR activity site and NS to be considered an independent location. Although rare,
there was occasional migration of individual sharks between the NS and SL from year to
year – limiting the independence of the shark populations from each site.
An additional problem arises from the limited time-span over which data is available. The
five years pre-dredging is sufficient, however more data is required post-dredging. The main
purpose of BACI designs is to observe differences between control and impact locations
before impacting activities, and then compare these differences to those between the two
locations after the impacting activity. The four years post-dredging do not yield sufficient

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values for any changes in difference between control and impact locations to be considered
statistically significant.
The end result is that it is very difficult to come to a conclusion based on anything other than
theory that the reduction in total length, weight, growth rate and 1st
year survival of juvenile
lemon sharks in the Bimini lagoon is anything other than natural variation. However, the
theory is based upon considerable scientific evidence, supported by a number of well
respected scientists – see Gruber & Parks (2002), Gruber et al. (2002), Feldheim & Edren
(2002).

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7. CONCLUSIONS

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7.1 Conclusions
Decades of scientific research have shown the Bimini lagoon to function as a nursery for
juvenile lemon sharks along with many other species of reef fish and marine organisms. The
mangrove shoreline and seagrass beds provide an essential habitat for the safe growth and
development of these species in the early stages of their lives. The survival of these species
relies upon the effective functioning of this nursery habitat in order to ensure sufficient
replacement of reproductively mature adults. As a top predator, the juvenile lemon shark is
an excellent indicator of the overall health of this nursery ecosystem.
The construction of BBR began with mangrove destruction in 1997, followed by sporadic
and often intense dredging of the Bimini lagoon floor between 1999 and 2002. The analysis
of shark catch data between 1995 and 2003 revealed several trends in the properties of the
juvenile lemon shark population of the lagoon – most notably in differences between pre-
dredging (1995-1999) and post-dredging (2000-2003) periods. Post dredging, the sharks
experienced a significant reduction in growth rate, total length and weight, along with a large
drop in 1st
year survival rate. In addition to this, periods of most intense dredging activity
yielded some of the lowest total catches and numbers of recaptured sharks ever recorded
during the 9 years of sampling. During those periods, the sharks captured from the already
diminished populations showed signs of severe physiological and neurological stress never
observed before – leading to record numbers of sharks dying during capture.
Although the juvenile lemon shark population appears to be showing signs of recovery since
this dredging activity has ceased, it is hypothesised that continued monitoring of the

Alex Brown 2004
population may identify further impacts as the more delayed effects of the dredging take
their toll on the lemon sharks. Judging by their response to the dredging activity that has
already taken place, it is predicted that the sedimentation, disturbance and habitat destruction
that will be associated with the proposed future development of BBR will cause sufficient
ecological damage to destroy the North Sound environment completely, and severely
damage the rest of the lagoon. This will render the Bimini lagoon ineffective as a nursery
habitat, and decimate the populations of marine organisms which use it for this purpose.
The adult females lemon shark’s loyalty to a specific nursery ground and the consequent
non-replacement of reproductively mature adult lemon sharks will eventually lead to a crash
in their population throughout the western Great Bahamas Bank, should the proposed BBR
development take place. The resultant top-down effect of removing an apex predator from
the ecosystem will have serious and widespread negative effects throughout this area.
Therefore, it is essential for the government to not only recognise the importance of these
nursery habitats, but to successfully provide them with the environmental protection required
to stop projects such as BBR from destroying them.

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REFERENCES
Allen, T.B. 1999. The Shark Almanac. The Lyons Press. p108-109.
BEST. 2002. Bahamas Environmental Handbook. Bahamas Environment, Science and
Technology Commission (BEST).
The Bahamas Tribune, Miami Herald Bahamas Edition.
Duncombe, S. February 11th
2001. Bimini developer: have faith in me.
Smith, G. April 8th
2002. Dredging killing fish concern as Bimini work resumes.
Downes, B.J., Barmuta, L.A., Fairweather, P.G., Faith, D.P., Keough, M.J., Lake, P.S.,
Mapstone, B.D., Quinn, G.P. 2002. Cambridge University Press. p120.
Feldheim, K.A., Gruber, S.H., Ashley, M.V. 2002. The breeding biology of lemon sharks at
a tropical nursery lagoon. Proceedings of the Royal Society of London Series B- Biological
Sciences 269 (1501): 1655-1661.
Feldheim, K.A., Edrén, S.M. 2002. Impacts of dredging on marine communities – the Bimini
Lemon Shark. Bahamas Journal of Science 9(2): 28-35.
Field, C.D. 2000. Mangroves. Seas at the Millenium: An Environmental Evaluation. Elsevier
Science Ltd.
Fowler, J., Cohen, L., Jarvis, P. 1998. Practical Statistics for Field Biology. John Wiley &
Sons. p7.
Greenberg, J., Greenberg, I., Greenberg, M. 2000. Mangroves, Trees in the Sea. Seahawk
Press.

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Gruber, S.H., Nelson, D.R. and Morrissey, J.F. 1988. Patterns of activity and space
utilization of lemon sharks, Negaprion brevirostris, in a shallow Bahamian lagoon. Bulletin
of Marine Science 43:61-76.
Gruber, S.H., deMarignac, J.R.C., Hoenig, J.M. 2001. Survival of juvenile lemon sharks at
Bimini, Bahamas, estimated by mark depletion experiments. Transactions of the American
Fisheries Society 130: 376-384.
Gruber, S.H. and Parks, W. 2002. Mega-resort development on Bimini: sound economics or
environmental disaster? Bahamas Journal of Science 9(2):2-18.
Gruber, S.H., Grant, A.T., Newman, S.P. 2002. Effects of large scale seafloor excavation in
the Bimini lagoon. Bahamas Journal of Science 9(2):36-40.
Guerin, J.L., Stickle, W.B. 1992. The effect of salinity gradients on the tolerance and
bioenergetics of juvenile blue crabs (Callinectes sapidus) from waters of different
environmental salinities. Marine Biology 114: 391-396.
Heffernan, J.J., Gibson, R.A. 1983. A comparison of primary production rates in Indian
river, Florida, seagrass systems. Florida Scientist 46: 295-306.
Hutton, W. 2002. Bimini Revisited. The Hutton Commentaries.
http://www.huttoncommentaries.com/Other/Bimini/2002ERATrip/bimini_revisited.htm
Jacobsen, T. 1987. An ecosystem study of a shallow Bahamian lagoon: Biomass estimation
of the lemon shark (Negaprion Brevirostris) a top consumer predator. PhD Thesis, University
of Georgia, Athens.
Kresge, D. 2003. The Bimini Cruising Guide. Bluewater Books & Charts, Fort Lauderdale,
Florida, USA.

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Lewis, M., Lewis, S. 2002. Explorers Chartbooks.Com. Key West Florida. January 2002.
http://www.explorercharts.com/nearbahamasupdates.html
Lugo, A.E., Snedaker, S.C. 1974. Properties of a mangrove forest in southern Florida.
Proceedings of the International Symposium on Biology and Management of Mangroves.
October 8 – 11. East-West Centre, Honolulu, Hawaii.
Lutz, S., Broad, K., Talaue-McManus, L., Sanchirico, J., Stoffle, R. 2002. Human
dimensions of marine reserve policy – applications in Bimini. Bahamas Journal of Science
9(2): 50-57.
Morrissey, J.F. and Gruber S.H. 1993. Home range of juvenile lemon sharks, Negaprion
brevirostris. Copeia 2:425-434.
Musick, J.A., McMillan, B. 2002. The Shark Chronicles: A Scientist Tracks the
Consummate Predator. Time Books. Henry Holt and Company, LLC.
Nagelkerken, I., Van der Velde, G., Gorissen, M.W., Meijer, G.J., Van’t Hof, T., den Hartog,
C. 2000. Importance of mangroves, seagrass beds and the shallow coral reef as a nursery for
important coral reef fishes, using a visual census technique. Estuarine, Coastal and Shelf
Science 51:31-44.
Nassau Guardian
Lightbourne, K. February 7th
2003. Government to meet with Bimini Bay developer.
Lightbourne, K. April 11th
2003. Bimini Bay project shelved.
Lightbourne, K. April 15th
2003. Scaled-down Bimini project ‘unstopped’.
Newman, S.P., Gruber, S.H. 2002. Comparison of mangrove and seagrass fish and
macroinvertebrate communities in Bimini. Bahamas Journal of Science 9(2):19-27.

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Riegel, B. and Piller, W.E. 2000. Mapping of benthic habitats in northern Safaga Bay (Red
Sea, Egypt): a toll for pro-active management. Aquatic Conservation of Marine Freshwater
Ecosystems 10: 127-140.
Sarda, R., Pinedo, S., Gremare, A., Taboada, S. 2000. changes in the dynamics of shallow
sandy-bottom assemblages due to sand extraction in the Catalan Western Mediterranean Sea.
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Stevens, J.D., Bonfil, R., Dulvy, N.K., Walker, P.A. 2000. The effects of fishing on sharks,
rays and chimaeras (chondrichthyans), and the implications for marine ecosystems. ICES
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British West Indies. Amer. Mus. Novit. 1822:1-12.
URL: 1. Bimini Biological Field Station. Last accessed: February 2004.
http://www.miami.edu/sharklab/maps/bimini.htm
URL: 2. Bimini Biological Field Station PIT Programme 2003. Last accessed: February
2004.
http://wetpixel.com/features/pit/
URL: 3. The Bahamian. Bimini: facts, history and information. Last accessed: February
2004.
http://islands.thebahamian.com/bimini.html

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URL: 4. Gruber, S.H., deMarignac, J.R.C., Hoenig, J.M. 2001. Survival of juvenile lemon
sharks at Bimini, Bahamas, estimated by mark depletion experiments. Last accessed:
February 2004.
http://www.fisheries.vims.edu/hoenig/lemonshark/lemonsharks.htm
URL: 5. Bimini Bay Resort and Casino. Latest happenings. Last accessed: February 2004.
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Last accessed: February 2004.
URL: http://wetpixel.com/features/pit/

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APPENDIX

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A 1. The Bimini Islands, as shown on Chart 38B issued by the International
Sailing Supply. Water depths are shown in metres. The chart pre-dates any major
development activity. Source: Hutton, 2001.
N

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A 2. Satellite image of the BBR site, as of 2001. Source: Hutton, 2001.

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A 3. Description of results of Kruskal-Wallis Tests – comparing the data for pre and post-
dredging periods for the variables shown. Where P >0.05, then accept the null hypothesis of
no significant difference between the medians. Where P ≤0.05, then reject the null
hypothesis of no significant difference between the medians to the 95% level of significance.
Where P ≤0.001, a highly significant difference at the 99% level is present.
Kruskal-Wallis Test: Growth rate in the North Sound
Kruskal-Wallis Test on GR
NSD N Median Ave Rank Z
1 124 0.3415 100.3 0.94
2 70 0.3105 92.5 -0.94
Overall 194 97.5
H = 0.88 DF = 1 P = 0.349
H = 0.88 DF = 1 P = 0.349 (adjusted for ties)
Kruskal-Wallis Test: Growth rate in Sharkland
Kruskal-Wallis Test on GRTH
SKLD N Median Ave Rank Z
1 111 0.4620 135.3 2.71
2 132 0.3640 110.8 -2.71
Overall 243 122.0
H = 7.32 DF = 1 P = 0.007
Kruskal-Wallis Test: Growth rate in the whole lagoon
Kruskal-Wallis Test on gr
wlagn N Median Ave Rank Z
1 235 0.4290 231.1 2.15
2 202 0.3570 205.0 -2.15
Overall 437 219.0
H = 4.64 DF = 1 P = 0.031
Kruskal-Wallis Test: Weight in the North Sound
Kruskal-Wallis Test on WT
NS N Median Ave Rank Z
1 394 1.500 336.7 3.09
2 243 1.400 290.3 -3.09

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Overall 637 319.0
H = 9.57 DF = 1 P = 0.002
Kruskal-Wallis Test: Weight in Sharkland
Kruskal-Wallis Test on WGT
Skl N Median Ave Rank Z
1 427 1.650 448.7 3.89
2 406 1.500 383.7 -3.89
Overall 833 417.0
H = 15.17 DF = 1 P = 0.000
Kruskal-Wallis Test: Weight in the Whole Lagoon
Kruskal-Wallis Test on wt
wlgn N Median Ave Rank Z
1 821 1.600 779.9 4.51
2 649 1.450 679.4 -4.51
Overall 1470 735.5
H = 20.32 DF = 1 P = 0.000
Kruskal-Wallis Test: Total length in the North Sound
Kruskal-Wallis Test on TLG
NSND N Median Ave Rank Z
1 394 66.00 333.0 2.44
2 243 64.90 296.3 -2.44
Overall 637 319.0
H = 5.96 DF = 1 P = 0.015
Kruskal-Wallis Test: Total length in Sharkland
Kruskal-Wallis Test on L
SL N Median Ave Rank Z
1 427 66.90 423.7 0.83
2 406 67.05 409.9 -0.83
Overall 833 417.0
H = 0.68 DF = 1 P = 0.408

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Kruskal-Wallis Test: Total length in the Whole Lagoon
Kruskal-Wallis Test on tl
wl N Median Ave Rank Z
1 821 66.50 754.9 1.97
2 649 65.90 710.9 -1.97
Overall 1470 735.5
H = 3.89 DF = 1 P = 0.049

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A 4. Map of proposed boundaries of the planned Bimini NTMPA. Image originally from
Bahamas Department of Fisheries. Adapted from: Lutz et al., 2002.

Lemon Shark Population Decline Due to Bimini Resort Dredging

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