Pedestal Study for Diversity of Fishes, Crabs and Shrimps in Kokkilai Lagoon of Sri Lanka

Abstract

Kokkilai Lagoon is a large estuarine lagoon located in Mullaitivu and Trincomalee districts of Sri Lanka. It consists of sea grass beds, oyster beds, mangrove swamp and mudflats, particularly in the western and southern shores and bounded by cultivated lands and scrub forest and some by open forest patches. The natural productivity and rich diverse resources of gives economic values to the lagoon. Even though still there is no confirmation about its faunal and floral diversity. Since, a study was conducted during a year period of September 2012 to October 2013, with an objective of identification of fishes, crabs and shrimp found in the lagoon ecosystem. Study revealed that 55 fish species belongs to 34 fish families were recorded. Among fish families three families; Cichlidae, Clupeidae and Leiognathidae were observed as dominant diversity families in this lagoon. Most massive crab species Scylla serrata and prevails throughout the year. Portunus pelagicus also plentiful in lagoon mouth area. Penaeus monodon and Penaeus sp. also abundant in the lagoon with some peak seasons. However, lagoon is being subjected to significant anthropogenic pressures that threaten to diminish the value of its biodiversity, fisheries and natural habitats.

Full text

Advances in Biological Research 9 (1): 49-52, 2015
ISSN 1992-0067
© IDOSI Publications, 2015
DOI: 10.5829/idosi.abr.2015.9.1.924
Corresponding Author: N. Thiruchchelvan, University College of Jaffna,
University of Vocational Technology, Sri Lanka.
49
Pedestal Study for Diversity of Fishes, Crabs and
Shrimps in Kokkilai Lagoon of Sri Lanka
G. Krishanthan, N. Thiruchchelvan and G. Mikunthan
12 3
Sevalanka Foundation, Kilinochchi, Sri Lanka
1
University College of Jaffna, University of Vocational Technology, Sri Lanka
2
Department of Agricultural Biology, Faculty of Agriculture, University of Jaffna, Sri Lanka
3
Abstract: Kokkilai Lagoon is a large estuarine lagoon located in Mullaitivu and Trincomalee districts of Sri
Lanka. It consists of sea grass beds, oyster beds, mangrove swamp and mudflats, particularly in the western
and southern shores and bounded by cultivated lands and scrub forest and some by open forest patches. The
natural productivity and rich diverse resources of gives economic values to the lagoon. Even though still there
is no confirmation about its faunal and floral diversity. Since, a study was conducted during a year period of
September 2012 to October 2013, with an objective of identification of fishes, crabs and shrimp found in the
lagoon ecosystem. Study revealed that 55 fish species belongs to 34 fish families were recorded. Among fish
families three families; Cichlidae, Clupeidae and Leiognathidae were observed as dominant diversity families
in this lagoon. Most massive crab species Scylla serrata and prevails throughout the year. Portunus pelagicus
also plentiful in lagoon mouth area. Penaeus monodon and Penaeus sp. also abundant in the lagoon with some
peak seasons. However, lagoon is being subjected to significant anthropogenic pressures that threaten to
diminish the value of its biodiversity, fisheries and natural habitats.
Key words: Fish Prawn Crab Lagoon Kokkilai Sri Lanka Biodiversity
INTRODUCTION and Aquatic Resources [5] reported that in Sri Lanka
Total area of Mangrove forest in the world expected 158,016 km , Fresh water area 201,016 km , Lagoons and
as 150,000 km of which over 62000 km are tropical Asia Estuaries 158,000 ha, Mangrove Zones, mud flats and salt
22
[1]. In Sri Lanka mangrove jungles are disseminated, marshes 71,000 ha, Fresh water bodies 260000 ha,
chiefly beside Northern, Northeastern and Eastern coasts Perennial reservoirs 155,000 ha, Seasonal tanks 100,000 ha,
bordering lagoons and river estuaries [2]. In 1995, Legg Villus 5,000 ha.
and Jewell [3] reported that Sri Lankan mangrove forest Kokkilai Lagoon is a one of large estuarine lagoon in
cover only about 0.1-0.2 % of the total land area of the Sri Lanka, located in Northeastern Sri Lankan districts of
island (66,666 km ). Most of the Mangrove forests have Mullaitivu and Trincomalee. The Kokkilai lagoon area
2
been subjected to the human interference for the long time declared a Wildlife Sanctuary under the Fauna and Flora
and therefore undisturbed mangrove forest are rare. Protection Ordinances in 1951. The lagoon consists of sea
Sri Lanka also has extensive fresh water and brackish grass beds, oyster beds, mangrove swamp and mudflats,
water resources for carrying out fishing activities. particularly along the western and southern shores and it
According to National Aquaculture Development is surrounded by cultivated lands and scrub forest and
Authority (NAQDA) fresh water bodies comprise of also with some patches of open forest. The Kokilai
around 260,000 ha of large irrigation reservoirs, Medium Lagoon is further significant because of its natural
irrigation reservoirs, Minor Irrigation reservoirs, seasonal productivity as well as rich and diverse resources.
village tanks, flood lakes, upland reservoirs/estate tanks Because of these economic values of the Kokkilai lagoon
and Mahaweli River basins [4] and Ministry of Fisheries and still there are no confirmation about it faunal and
contained 62,705 km Inland waters, Brackish water area
2
22

Advan. Biol. Res., 9 (1): 49-52, 2015
50
floral diversity as well. So that, this study was conducted lagoon are extensive and supply sand for dune formation
for identification of fishes, crabs and shrimp found in the by wind and also sand are rich in illmenite which imparts
lagoon ecosystem. black color into the sand in the area.
MATERIALS AND METHODS Aquatic Faunal Association in the Kokkilai Lagoon:
Study Area: to the 34 fish families were recorded in study period.
Kokkilai Lagoon: Kokkilai Lagoon (8°56'-9°03'N, Among these 34 fish families three fish families which are
80°52'-80°58'E) a large estuarine lagoon (2,995 ha) located Cichlidae, Clupeidae and Leiognathidae were recorded as
in Mullaitivu and Trincomalee districts of Sri Lanka. The dominant diversity families in this lagoon. Plate 1, shows
lagoon consists of sea grass beds, oyster beds, mangrove the most diverse fish species found in the Kokkilai
swamp and mudflats, particularly along the western and Lagoon during the study period.
southern shores and it is surrounded by cultivated lands Tables 1(A) and 1(B) illustrate the fish species
and scrub forest and also with some patches of open recorded from Kokkilai lagoon from September 2012 to
forest. The Nagachola forest reserve, Anandakulum forest October 2013. Kokkilai has been settlements for migratory
reserve and the stretch of forest running along the fishermen for centuries. Many migrant fishermen from
Kokkilai lagoon all serve as valuable habitats for local Western and Northwestern province as well as native
wildlife. The stretch of land from Kumalamune to Kokkilai fishermen do fishing in the lagoon. Fishing in the lagoon
lagoon is still remains as a dense forest. remains as open access and the fishery are comprises of
The lagoon is fed by several small fresh water an artisanal fishery, modern fishery and destructive
streams and mainly by excess water from Padaviya Tank fishery. Cast nets, drift nets, gill nets, hooks and lines,
during the rainy season; it is linked to the sea by a narrow various traps, fixed hoop nets and large set nets are used
channel and is seasonally tidal, but for some months of for fishing in the lagoon which operated from FRP
the year; the channel is blocked by a sand bar. The motorized boats, sail-driven outrigger canoes, small
maximum depth near the mouth of the channel is about canoes, sail-driven outrigger canoes. Using of destructive
four to five meters; the water is brackish, with the salinity fishing gears including mono filament nets, open access,
increasing to about 33±3 ppt seasonally and during the chasing of fishing grounds daily, sedimentation and
North-East monsoon period salinity becomes quite low excess filamentous green algae, destruction of mangroves
due to spill water from Padaviya Tank and surface run off. appears as threats to fishery resources and fish habitats
Survey of Aquatic Faunal Association in the Kokkilai Resources in 2006 also reported that excessive amounts of
Lagoon: Fish, prawn and crab samples were collected uncoordinated assistance during the post-tsunami period
continuously during the survey period from September appear to have resulted in an over-supply of boats, which
2012 to October 2013. Fish, prawn and crab species were may have exacerbated the over-exploitation of coastal
taken to the laboratory for proper identification and fisheries, a problem of the government and development
taxonomy. All of above faunal species except fish species agencies [8].
were identified according to the FAO guide [6] while fish
species were identified using Olaosebikan and Raji [7]. Crabs and Shrimps Found in the Kokkilai Lagoon:
RESULTS AND DISCUSSION observed as most attractive and economically viable
Mangroves, scrubs and open forest in the area Table 2 shows the crab and shrimp species recorded
provide niches for nesting and roosting. Kokkilai lagoon during the study period. Most popular crab species in the
and adjacent forest areas provide feeding grounds for lagoon is Scylla serrata (Plate 2) and the lagoon is well
several bird species, especially for migratory waders. known for the Scylla serrata fishery and the fishery
The Kokkilai lagoon is separated by beach-dune systems prevails throughout the year with some peak seasons.
from the sea on the east. The beaches are wide, gently Portunus pelagicus also abundant in the areas near by
sloping and used in beach seine fishing and for landing lagoon mouth during the months of July, August,
small-scale fishing crafts. The beaches that front the September and October 2013. Penaeus monodon (Plate 2)
Altogether there are 55 fish species which all are belongs
in the lagoon. Ministry of Fisheries and Aquatic
Prawns (Penaeus sp.) and Mud crab (Scylla serrata) were
fishing with some peak seasons (Plate 2).

Advan. Biol. Res., 9 (1): 49-52, 2015
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Plate 1: Most diverse fish species found in the Kokkilai Lagoon (A) Etroplus suratensis (B) Oreochromis niloticus
Plate 2: Most observed prawn and crab species in Kokkilai Lagoon (A) Penaeus monodon (B) Scylla serrata
Table 1(A): Fish Species Recorded from Kokkilai Lagoon
No Family Scientific Name Common Name
1. Ambassidae Ambassis gymnocephalus Bald glassy
Ambassis commersoni Common glass fish
2. Anguillidae Anguilla bicolor bicolor Short fin eel
3. Ariidae Arius thalassinus. Arius caelatus Giant cat fish
Engraved catfish
4. Belonidae Stongylura strongylura. Spot tail needle fish
5. Carangidae Caranx sexfasciatus Big eye trevally
6. Clariidae Clarias brachysoma Walking cat fish
7. Chanidae Chanos chanos Milk fish
8. Cichlidae Etroplus suratensis Banded etroplus
Etroplus maculates Spotted etroplus
Oreochromis mossambicus Thilapia
Oreochromis niloticus Nile tilapia
9. Serranidae Epinephelus coioides Orange spotted grouper
Epinephelus malabaricus Malabar grouper
10. Gerreidae Gerres filamentosus Whip fin silver biddy
Gerres abbreviatus Deep body silver biddy
11. Clupeidae Herklotsichthy squadrimaculatu Blue stripe herring
Hilsa kelee Kelee shad
Sardinella albella White sardinella
Nematalosa nasus Bloch’s gizzard shad
12. Ephippidae Ephippus orbis Orb fish
13. Engraulididae Stolephorus commersonii Commersonii’s anchovy
14. Hemiramphidae Hyporhamphus limbatus Congaturi halfbeak
Hyporhamphus dussumieri Dussumier’s halfbeak
15. Sphyraenidae Sphyraena jello Pickhandle barracuda
16. Lutjanidae Lutjanus argentimaculatus Mangrove red snapper
Lutjanus fulviflamma Black spot snapper
17. Centropomidae Lates calcarifer Giant sea perch/seabass
18. Leiognathidae Leiognathus brevirostris Short nose ponyfish
Leiognathus dussumieri Dussumier’s pony fish
Leiognathus splendens Splendid pony
Leiognathus equalus Common pony fish
19. Monodactylidae Monodactylus argenteus Silver moony
Monodactylus falciformis Full moony

Advan. Biol. Res., 9 (1): 49-52, 2015
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Table 1 (B): Fish Species Recorded from Kokkilai Lagoon
No Family Scientific Name Common Name
20. Mugilidae Mugil cephalus Flat head mullet
Valamugil buchanani Blutail mullet
21. Siganidae Siganus jarvus Streaked spine foot
Siganus lineatus Gold lined spine foot
22. Terapontidae Terapon jarbua Jurbua terapon/iribataya
Terapon puta Small scaled terapon
23. Polynemidae Eleutheronema tetradactylum Four finger threadfin
24. Scatophagidae Scatophagus argus Spotted scat/illattiya
25. Dasyatidae Dasyatis kuhlii Blue spotted sting ray
Pastinachus sephen Cowtail stingray
26. Channidae Channa striata Murrel/loola
27. Gobidae Glossogobius guris Bar-eyed goby
28. Ophicephalidae Ophicephalus striatus Striped snake head
29. Periopthalmidae Periopthalmus koelreuteri Mud skipper
30. Tetratodontidae Trtradon fluriatalis Puffer fish
31. Triacanthidae Triacanthus biaculeatus Short nosed tripod fish
32. Soleidae Euryglossus orientalis Oriental sole
33. Sciaenidae Nibea maculata Blotched croaker
34. Nemiperidae Scolopsis bimaculatus Thumbprint monocle bream
Table 2: Crabs and shrimp species recorded from Kokkilai lagoon
No Family Scientific Name Common Name
1 Palaemonidae Macrobrachium
rosenbergii* Giant river prawn
2 Penaeidae Penaeus indicus Indian white shrimp
3 Penaeidae Penaeus semisulcatus Green tiger prawn
4 Penaeidae Penaeus monodon Giant tiger prawn
5 Portunidae Portunus pelagicus Blue swimming crab
6 Portunidae Scylla serrata Indo-pacific swamp crab
*Recoded only a time during December 2012 from Southern part of the
lagoon
and other Penaeus sp. also aboundant in the lagoon with
some peak seasons. According to the Ministry of
Fisheries and Aquatic Resources Development [9]
statement, These crab species such as Scylla serrata and
Portunus pelagicus as well as prawn speices P. monodon,
P. indicus, P. semisulcatus are commonly found in Sri
Lanka.
CONCLUSION
Kokkali lagoon was observed as very rich in faunal
diversity in terms of 34 families of fish enclose 55 fish
species, four prawns’ species and two crabs’ species were
observed.
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