This document discusses the kraal fishery of Bolgoda Lake in Sri Lanka and strategies for its co-management. It first provides background on traditional and government-led fisheries management approaches and their limitations. It then describes the study site of Bolgoda Lake and the existing kraal fishery system. The study analyzed catch data from 10 kraals to determine how yield varies with factors like salinity, lunar cycle, depth and distance from sea. It found the yield is significantly affected by salinity and lunar cycle. Interviews assessed the current top-down management system's weaknesses. The document recommends a co-management strategy involving local fishers, authorities and other stakeholders to sustainably manage this important fishery

1. KRAAL FISHERY OF ‘BOLGODA LAKE’
AND STRATERGIES FOR CO-
MANAGEMENT
K.A.D.C.J.KAHANDAWALA
Student number: FGS/01/09/07/2005/0015
Supervisor:-Dr.W.U. Chandrasekara

2. Introduction
 Fisheries have been traditionally seen as common
property resources and it lead to a collapse of the fish
stock.
 Three major fisheries management strategies have been
employed prevent or reduce this collapse or
overexploitation.
 They are;
01) Community based fisheries Management (CBRM),
02) Government control fisheries management, and
03) Fisheries Co-management.

3. CBRM and Government control
fisheries management.
 CBRM practice is not a
suitable solution for
effective management of
fisheries resources within
the framework of modern
socio-economic
environment.
 The government control
fisheries management is
failure due very much
centralized top-down
approach and it based
exclusively on formal
biological science.
 It mostly disregards the
experiences of fishers

4. Fisheries co-management
 Fisheries experts now recognize that resource conflicts
can be minimized and the resources are better managed
if fishers and other resource stakeholders are more
involved in the fisheries.

5. Bolgoda Lake
 Bolgoda Lake is situated in the
South West of Sri Lanka, 19 Km
from Colombo.
 The lake consists of two major
water bodies and covers 374 Km2
partly fresh and brackish water
 This system is made up of two
interconnected lakes and their
waterways.
 The North Lake, parts of which
belong to both Colombo and
Kalutara districts, is the larger.
 It discharges to the sea through
the Panadura estuary.
 The South Lake is situated in
Kalutara district and it is
connected to the sea through
Thalpitiya Ela .
Sri Lanka
North Lake
South Lake
Hirana
Rukgaha thotupala
Railway
Main road
Colombo
Diggala
Wawala
Talpitiya
Panadura
0 1 2 3
Km
SCALE
Moratuwa
Maha bellana
Pinwatta
Rambana
1
2
3
4
5
6
7
89
10
N

6. Two different kraals in bolgoda lake
Normal chamber kraal Lifting chamber kraal
In the Bolgoda Lake, mainly 4 major shrimp species are caught in the kraal fishery
Metapenaeus dobsoni (Kadal shrimp/Mal issa)
Metapenaeus monoceros (Speckled shrimp/Rat issa/Gal issa)
Penaeus monodon (Giant tiger shrimp/Karandu issa)
Penaeus indicus (Indian white shrimp/Kiri issa)
Fisheries play an important role of the Bolgoda area. Shrimp is one of the major
sources of income for the people and caught by constructing ‘Jakottu’ (Kraals).

7.  About 70 Kraals are in operation seasonally at Bolgoda
Lake.
 Well before the 1920s, the kraal fishery of Bolgoda Lake
has been managed through a CBRM system.
 Since 1931, the existing CBRM system was reinforced by
the regulations made by Moratuwa Urban District
Council.
 More recently, the central government declared Bolgoda
Lake as a “Special Fisheries Management Area ” and new
regulations were introduced.
 However, these regulations and rules appear to be non-
functioning

8. Hypothesis
 A traditional CBRM system has been in operation over
generations to manage the kraal fishery in the Bolgoda
Lake. Since recently, this traditional CBRM system was
reinforced by the government regulations as such a co-
management strategy presently exists there.
 It can be hypothesized that the existing system in the
kraal fishery would bring about effective equity sharing
of resources among fishers and other relevant
stakeholders.

9. Objectives
 01. To find out whether the yields of the kraal fishery
of the Bolgoda Lake vary with the salinity, lunar
pattern, depth, and distance from the sea.
 02. Investigate the existing kraal fishery management
system of Bolgoda Lake and asses its effectiveness.
 03. Recommend suitable co-management strategies
for the kraal fishery in the Bolgoda Lake with out
comes of objectives 1 and 2 above.

10. Data and information collection
 Daily catch data were collected from 10 randomly
selected Kraals from various fishing areas of the lake
(January-May) 2008.
 Information on the nature of the management system of
the kraal fishery were collected by interviewing randomly
selected kraal owners.
 Other relevant government officers, knowledgeable
individuals and stakeholders relevant to the kraal fishery
in Bolgoda Lake.

11. Data analysis
CPUE of the two shrimp species of Metapenaeus dobsoni
and Metapenaeus monoceros as well as the total shrimp
yield of kraals with respect to the following factors;
1) distance from the sea mouth (near and far),
2) two depth levels (<2m and >2m),
3) phases of lunar cycle (four phases; New moon, 1st
quarter, Full moon and 2nd quarter), and
4) average salinity per lunar phase,
were analyzed using a multi-way ANOVA
significant result was further analyzed by one-way ANOVA (α
= 0.05) followed by Tukey’s pair wise comparison test (α =
0.05). All statistical analyses were carried out using
MINITAB (version 11.12) statistical package for windows.

12. Result
January February March April May
Metapenaeus
dobsoni
187.69+13.19 192.91+12.75 166.16+21.61 72.67+3.23 14.68+2.29
Metapenaeus
monoceros
50.9+10.58 58.29+9.79 101.37+20.03 83.67+5.37 10.33+1.10
Penaeus
monodon
0.41+0.21 0.92+.0.72 1.65+0.88
Penaeus
indicus
2.3+1
The species-wise mean monthly harvest (kg kraal-1 month-1) of shrimps from
the 10 selected kraals in the Bolgoda Lake during January-May 2008

13.  Monthly variation of the total harvest of the
Metapenaeus dobsoni and Metapenaeus
monoceros of kraal fishery of Bolgoda Lake
during January-May 2008. Mean yield and
the SE are presented.
0
50
100
150
200
250
January February March April May
Time (Month)
Yield+SE(Kg/Kraal/month)
Metapenaeus dobsoni Metapenaeus monoceros
 Monthly variation of the total shrimp harvest
in the kraal fishery of Bolgoda Lake during
January-May 2008. Mean yield and the SE
are presented
0
50
100
150
200
250
300
350
January February March April May
Time (month)
Yield+SE(Kg/Kraal/month)

14. Figure 11. Compression of the CPUE in different lunar levels
of the lake
0
0.5
1
1.5
2
2.5
3
1st full moon 2nd new moon
Lunar lavels
Ln(CPUE+1)+SE
Metapenaeus dobsoni Metapenaeus monoceros Total
 Comparison of the harvest of the
Metapenaeus dobsoni , Metapenaeus
monoceros and total harvest at different
lunar levels at Bolgoda Lake during
January-May 2008. Ln of the mean yield
and SE are presented.
0
0.5
1
1.5
2
2.5
15-11ppt 10-6ppt 5-0ppt
Average salinity
Ln(PUE+1)+SE
Metapenaeus dobsoni Metapenaeus monoceros Total
 Comparison of the harvest of the
Metapenaeus dobsoni , Metapenaeus
monoceros and total harvest at different
salinity ranges at Bolgoda Lake during
January-May 2008. Ln of the mean yield
and SE presented.

15. 0
0.5
1
1.5
2
2.5
Near Far
Distance levels
Ln(CPUE+1)+SE
Metapenaeus dobsoni Metapenaeus monoceros Total
0
0.5
1
1.5
2
2.5
2m> 2m<
Depth levels
Ln(CPUE+1)+SE
Metapenaeus dobsoni Metapenaeus monoceros Total
Comparison of the harvest of the
Metapenaeus dobsoni , Metapenaeus
monoceros and total harvest at
different distance level at Bolgoda Lake
during January-May 2008. Ln of the
mean yield and SE are presented.
Comparison of the harvest of the
Metapenaeus dobsoni , Metapenaeus
monoceros and total harvest at different
depth level at Bolgoda Lake during
January-May 2008. Ln of the mean yield
and SE are presented.

16.  Results of the multi-way ANOVA the distance from the
sea, depth levels and lunar pattern did not significantly
affect the harvest of the Metapenaeus dobsoni (P>0.05)
 The harvest of Metapenaeus dobsoni was affected by the
variation of the salinity. (P<0.05 multi-way ANOVA)
 The harvest was significantly higher at highest at high
salinity ranges (P<0.05, Tukey’s pair wise test after one-
way ANOVA).
 However, all the factors tested significantly affected the
harvest of the Metapenaeus monoceros (P<0.05, multi-
way ANOVA) .
 It may be indicator of different species respond to such
factors are in different.

17.  The lunar cycle is the only factor that has an effect on
the overall shrimp harvest . (P<0.05, multi- way
ANOVA). Other factors are no significant effect on the
overall shrimp harvest
 The total shrimp harvest increased during the full moon
and the 2nd quarter phase while it dropped during the
new moon and the 1st quarter periods (P<0.05, Tukey’s
pair wise test after one-way ANOVA).
 According to the results there are no highly productive
areas in the Bolgoda Lake shrimp fishery and total
shrimp harvest in each kraal is more or less equal to
each other.
 Therefore, fishers have not defined a system to rotate
the fishing ground for equity sharing of shrimp fishery
resource.

18. Research Coastal & multi day Fishers in the
programs fishers co-operate Bolgoda Lake
Pradesheya Sabha
e.g. Keselwatta
Central government
Ministry of Fisheries and
Aquatic Resources
NARA
Department of
fisheries & NAQDA
EFS KFS AFS DFS KFS
Pradesheya Sabha
e.g. Keselwatta
Central government
Ministry of Fisheries and
Aquatic Resources
NARA
Department of
fisheries & NAQDA
EFS KFS AFS DFS KFS
Information of existing kraal fishery
management system
Fishers have lack of
knowledge about new
regulations.
They do not respect to
regulations due to
weaknesses of existing
monitoring system and the
implementation structure.
. No participation of other
stakeholders for the lake
fishery management.
Diagrammatic representation of the present management organization structure, responsible for the Bolgoda Lake fisheries
management.

19. Present Management problems and barriers of
bolgoda lake kraal fishery
 Due to absences of
proper management
and monitoring system
kraal fishery face many
problems.
 Due to the weaknesses
of the enforcement of
rule in the Bolgoda
Lake, fishers carry out
banned destructive
fishing gears.

20.  Increase in the number of
tourists and recreational
fishing. They use high speed
boats that damage the fish
kraals as well as the bank of
the lake.
 Illegal sand excavation is
another factor with excessive
development of the Bolgoda
area that leads to river bank
erosions.

21.  Due to Urbanization
waste and sewage are
major causes leading to
the Eutrophication.
 Saw dust is one of the
main environmental
problems in the Moratuwa
area including the
Bolgoda Lake.
 Cutting Mangroves and
used as timber and fuel
wood.

22.  Highest capital and
maintenance cost is
another main problem
of the kraal fishery
due to high price and
scarcity of bamboo
material

23. Ministry of fisheries &Aquatic Resources
Central Environment Authority
Forest Department
Local Government Agencies
Tourist Board
NGOs Rural Banking system
NARA DFAR NAQDA
A
CCD
Management
Forum of the
Bolgoda Lake
Representatives of the
fisheries organizations
Representatives of other
stake holders
Management center
Diagrammatic representation of the proposed co- management structure to
the kraal fishery in Bolgoda Lake.

24. Possible management strategies
 Existing regulations and licensing system could be used to prevent
illegal fishing gear usage. Establishment of fisheries data base with
the assistance of fishers and scientists is useful for the formulation
of new regulations.
 To minimize adverse impacts of industrial waste and sewage, proper
waste management could be introduced. Management center could
impose an environmental tax from those.
 The management center could develop a method to use saw dust as
an alternative for fuel wood, and it might prevent mangroves cutting
for fuel and the pollution of the lake.
 sand excavation system can be allowed with a permit system.
 low power engines are less effective.
 Through the reforestation and awareness programmes, mangroves
can be conserved and developed.

25.  As a solution for illegal land reclamation, the center can demarcate
boundaries of the lake. Then the regulations could be enforced and
the community could be mobilized against it.
 Through an identified bank, can be provided loan facilities for
fishers. According to the catch and effort data the highest yield is
achieved by the kraal fishers in the 2nd Quarter of the lunar phases.
It is a good economic indicator for bank to collect their loan
installments. Also they can launch saving programmes during this
period.
 Licensing fees, permits fees, donation and other environmental tax
fees could be credited to the co-management fund. It could be
utilized to meet the expenses of monitoring and implementation
cost of co-management, community’s welfare activities.

26.  The three consecutive
bridges constructed
across the Panadura River
and more recently
constructed water
breaker of the Panadura
fishing harbour, partially
block the water exchange
of lake.
 This could impede shrimp
recruitment.

27.  Modern bridges with minimum
or zero blocking the water
exchange pattern.