Abstract: ecological and Biological attributes of 24 varieties of edible gastropods and bivalves fro...

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Abstract: ecological and Biological attributes of 24 varieties of edible gastropods and bivalves from
your Gilbert Islands Kiribati, Group and Micronesia were assessed with regard to their resilience by
examining size at maturity, intertidal burying, adjacent subtidal populations, benthic mobility, and
larval type. Modern diving gear and outboard motors now provide human foragers usage of offshore
resources, although foraging for mollusks is basically confined to the intertidal and shallow subtidal
regions. Changes because of human demographic pressures have resulted in overexploitation of
numerous molluscan resources. It really is suggested how the sustainable consumption of
invertebrates and also other marine species for food and nonfood purposes in Kiribati rests with a
remodeled kind of marine tenure.
ATOLLS PRESENT Many different marine environments and molluscan resources who have
provided subsistence living to generations of Pacific islanders (Tebano et al. 1993, Taniera 1994).
Kiribati (Figure 1) is only one of more than 20 nations from the Pacific, every one of which possessed
a wealthy inshore fisheries tradition and lore. Recently, however, traditional ecological knowledge
(TEK) has suffered the inevitable decline that characterizes similar bodies of knowledge throughout
nearly all of Oceania. High human population density, urban drift, better extractive technologies,
and expanding market opportunities all have inevitably affected the ocean resources of those
islands. Within this study, I examined the prey biology and ecology of mollusk fisheries in Kiribati,
Gilbert Islands, checking out factors distinguishing vulnerable from resilient resources, in addition
to their effect on subsistence.
Can traditional ecological knowledge be wedded with modern technology to regenerate the
fisheries? Since the thrust on this paper is limited to prey biology and ecology from the context of
mollusk fisheries, specifics of analytic methodology relevant to foraging efficiency usually are not
discussed here, but are available in Thomas (1999).
Data on molluscan resources in the Gilbert Islands date back towards the l950s when Randall and
Banner (1952) described the invertebrates of Onotoa Atoll, but identifications were poor where there
were few detailed descriptions of exploitive strategies. A major interdisciplinary environmental
survey on the main atoll of Tarawa, Republic of Kiribati (Abbott and Garcia 1995), expanded species
identification and habitat description, and provided an assessment in the impact of human activities
(Figure 2). The Tarawa Lagoon Project of 1992-1994 (Paulay 1995) is a major study of the lagoon,
and data from that project are included in this research.
MATERIALS And Techniques
Several communities involved in subsistence and commercial exploitation of mollusks were
investigated intermittently between 1993 and 1998. Research focused on four atolls from the central
Gilberts: Abaiang, Tarawa (both urbanized and rural sectors), Maiana, and Abemama, and another
atoll from the Southern Group, Tabiteuea North (Thomas 1999). Data on various areas of mollusk
gathering were obtained by participantobservation and interviews, and in the Shellfish Gatherer
Survey (SGS) from the Tarawa Lagoon Project (TLP), in cooperation with BioSystems, Inc., of Santa
Cruz, California.

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h individuals and groups, on 73 foraging trips covering. Fire can spread swiftly
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help keep your crew safe.69 days, for the total of 139.63 hr of direct observation (286.92 forager-
hours). Mean group size was 2.6 foragers (SD = .9, n = 146). Fifty-nine different individuals took
part in these activities. If it had not been possible to record foraging activities directly, the relevant
information was elicited via interviews. An overall total of 65 foraging trips was recorded over a
duration of 51 days, for an estimated total of 88.5 hr of foraging effort (161 forager-hours). Mean
group size was 3.1 foragers (SD = .7, n = 148). An overall of 19 different individuals was
interviewed.

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d on data sheets presented by personnel of the TLP. These data came from landings across the
southern part of Tarawa Atoll, with samples taken between December 1992 and February 1994. This
information greatly expanded the sample dimensions of foraging events, with 83 foraging trips
covering 26 days and approximately 191 hr of foraging time (257 forager-hours). Mean group size
was 1.3 foragers (SD = .7, n = 112).
Prey type identifications and basic habitat information are based on Cernohorsky (1971, 1972),
Eisenberg (1981Abbott, Dance and ) (1982), Paulay (1995), and personal observations. For each and
every prey type, five factors were examined to help in distinguishing vulnerable from resilient
resources: (1) size at maturity; (2) intertidal burying; (3) adjacent subtidal populations; (4) benthic
mobility; and (5) larval type (see Catterall and Poiner 1987). In many cases, the description of
relevant properties was limited, reflecting gaps from the data.
Atoll Zonation and Molluscan Patch Types
From windward to leeward (Figure 3), the fundamental zones and molluscan patch types sign of the
open atolls from the Gilbert Islands would be the: (1) reef slope; (2) submarine terrace; (3) reef
front; (4) reef margin; (5) moat; (6) reef crest; (7) reef flat; (8) shoreline; (9) lagoon reef flat
including mangrove, sand flats, and sea grass beds; (10) lagoon floor and slope; and (11) leeward
reef.
THE SEAWARD REEF: The seaward reef slope descends steeply from the upper limit of vigorous
hermatypic corals at a depth of about 18 m for the deepest seaward part of the reef between 4000
and 6000 m. Inside the Gilberts, little is known of the biota below 40 m, but mollusks commonly
located in the upper reaches with this zone include Pinctada and Trochus (Wells 1957), that also
occur about the submarine terraces between depths of 15 and 18 m. The dominant mollusks about
the reef front, the shoreward face from the seaward reef slope where coral growth is sparse and

4. heavy surf dominates, are gastropods for example Patella and Trochus (Demond 1957). The seaward
reef margin, distinguished by spur-and-groove formations, which disperse and channel ocean water,
supports compact and encrusting corals and coralline algae like Porolithon. Mollusks present in this
zone include Trochus, Turbo and Cypraea and Drupa (Wells 1957, Zann 1982). Shoreward in the
seaward reef margin are moats, parts of shallow water normally awash even at extrem e low tide. In
several respects, moats resemble lagoon habitats, with the exception of the hard bottom of coralline
rock or gravel. Thick-branching Acropora and' Heliopora are definitely the dominant corals, along
with the mollusks include Cypraea, Lambis and Conus Hippopus hippopus, and Tridacna gigas
within the deeper sections (Wells 1957). The reef crest, a high-energy environment, demarcates the
seaward limit in the minn kota ipilot reef flat; it supports the gastropod Turbo setosus. The reef flat
is commonly exposed or barely awash at lowest tide. It includes a truncated floor zoned by the tides,
which effect varying levels of exposure and temperature between seaward edge and inshore margin.
The surface of the reef flat supports Turbo, Cypraea, Thais and Trochus along with other types of
gastropods adapted primarily as crab predators and to the force of waves (Banner and Randall
1952).
The shoreline of islets (motus) on lagoon and ocean sides is made up of both cemented and
uncemented topographic features. Beachrock, lithified beach sand and coral debris, and
conglomerates, cemented storm deposits between 1 and 2 m above low-tide level, are occupied by
dense concentrations from the gastropod Nerita plicata, adapted to stand up to heat and desiccation,
along with rain (Cloud 1952). Moderately to poorly sorted mediumgravel and sand, and cobbles that
rise with a relatively sharp improvement in slope over the reef flat harbor the bivalves Asaphis
violascens and also the small beach clam Atactodea striata. The latter is also locally abundant in
other intertidal sandy areas.
THE LAGOON: Lagoon beaches are typically well to moderately sorted, from fine sand to gravel;
highest elevation is generally below 1 m over the highest tide; and sand spits really are a common
feature, especially near interislet channels and as lagoon-directed seaward-produced growth at the

5. ends of your atolls. Asaphis Atactodea and violascens striata are typical within this zone (Paulay
1995).
The lagoon reef flat is generally a depositional surface established by ocean-to-lagoon sediment
transport. Sediments tend to be poorly sorted with a few silt. The reef flats are often better
developed along the sections facing the prevailing winds than elsewhere and therefore are zoned as
well as the windward reef flats. The reef flat is primarily intertidal, grading into subtidal zones
toward the center of the lagoon. Except during periods of westerly storms, waters are often calm.
Mangroves, mainly Rhizophora mucronata, may rim the shoreline. The sediments associated with
mangroves are characteristically soft, of sand together with rich organic matter. Fiddler crabs, Uca
sp., and stomatopod burrows appear in transitional areas between the mangrove sediments along
with the sand flats. The bivalve Gafrarium pectinatum is occasionally found in the mangroves.
Sand flats are definitely the most extensive habitat in the lagoon reef flat. The fauna varies with
depth in the water, scale of sand particles, quantity of wave action, and depth in the sand. This
habitat supports the economically important Anadara uropygmelana, Strombus luhuanus, and
Gafrarium pectinatum (Paulay 1995). The reduced subtidal and intertidal parts of the lagoon border
may support extensive beds of Thalassia hemprichii that stabilize and bind fine sand and silt
abundant in organic matter. The water grass beds are productive grounds for Anadara
uropygmelana, Trachycardium angulatum, Gafrarium pectinatum, Timoclea marica, Strombus
luhuanus, along with other mollusks (Paulay 1995).
Atoll lagoons in the Gilberts encompass a much larger area than the landmass. They vary from a
virtually enclosed lagoon at Marakei to poorly defined shallow expanses at Nonouti and Tabiteuea.
The http://www.yourdictionary.com/marine deepest lagoon, at Butaritari, at 33 m is shallower than
atoll lagoons inside the Marshalls and Tuvalu. Deep reef passes are confined to leeward lagoon
margins. There is an surge in live coral coverage and reduce in sediment coverage toward the
leeward margin. The lagoon slope, predominantly engrossed in sand or coral rubble, begins on the
deepest edge of the sea grass bed, approximately .5 m deep at low tide. It slopes gently to depths of
8-10 m at 1 km in the sea grass margin, if present. This region supports scattered colonies or clumps
of primarily Porites spp. and Pocillopora damicornis in South Tarawa. Mollusks including Anadara
psammophilic and uropygmelana crustaceans and echinoids predominate (Wells 1957, Paulay 1995)
on fringing or patch reefs often covered with Acropora around the lagoonal slope in North Tar awa.
The lagoon floor will be the essentially level bottom of a lagoon. Sandbars, pinnacles, coral knolls,
and patch reefs (dead and living) present sharp irregularities in the bottom. Lagoon depth,
sedimentation rates, along with other physical factors modify the development of coral and
consequently species diversity and density. Mollusks are uncommon and constitute just a small
fraction in the biomass on Tarawa. The leeward reef platform is observed as irregular outer reefs
and few or no islets. Leeward reefs are typically submerged over the majority of their area, even at
low tide, and show relatively vigorous coral growth. This zone supports Lambis and Tridacna. The
seaward slope is often much steeper than on windward reefs. Engine Maintenance
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submarine and slope Pinctada, terrace and Trochus could be
abundant (Wells 1957).
TIDES AND CURRENTS: The highest tidal fluctuations (spring
tides) occur in the times of new and full moons; the littlest
fluctuations (neap tides) are about halfway between spring tides,
during the foremost and last quarters. In Tarawa Lagoon,
semidiurnal tides have a mean amplitude of 1.5 m (neap range, 12 m; spring range, 1.8 m) (Gillie
1993). Fluctuations in sea level (in the order of 10-20 cm) follow seasonal variations in the strength
and location from the trade winds. In the El Nino event in 1982-1983, the monthly mean sea level
was 28 cm above the long term mean in 1982, but 21 cm below mean in late 1983. Repeated cycles
of submergence and variation and exposure along these lines because of lunar periodicity make the
intertidal a zone of high environmental stress.