Biodiversity of Gulf of Mannar

Biodiversity of Gulf of Mannar

Gulf of Mannarlarge shallow bay

lies between the southeastern tip ofIndiaand the west coast ofSri Lanka.

The estuaries ofThamirabarani Riverof south India and theAruvi Aru Riverof Sri Lanka drain into the Gulf.

is a large shallow bay forming part of theLaccadive Seain theIndian Ocean. A chain of low islands and reefs known asAdam's Bridge, also called Ramsethu, which includesMannar Island, separates the Gulf of Mannar fromPalk Bay, which lies to the north between India and Sri Lanka. 2

GEOGRAPHICAL LOCATION

Palk Strait

Palk Bay

Adams Bridge

Gulf of Mannar

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About gulf of mannarSome features: 1986- declared theGulf of Mannar Marine National Park. 1989-The park and its 10km buffer zone were declared aBiosphere ReserveFirst marine Biosphere Reserve in South East Asia, a chain of 21 islands (10,500km)

Home to 3,600 rare Species of flora and fauna like fishes, coral reefs, sea horse, algae, marine plants

a group of 21 islets lying off the Tamil Nadu coast betweenThoothukudiandDhanushkodiwere 4

The islets and coastal buffer zone includesBeachesEstuariesTropical dry broadleaf forests The marine environments includeSeaweedcommunities Sea grass communitiesCoral reefs Salt marshesMangroveforests

Gulf of Mannar reefslie along the 140 km stretch between Tuticorin and Rameswaramlatitude 847' N and 9 15' N longitude 78 12' E and 79 14'E.Mannar Barrier reef which is about 140 km long and 25 km wide between Pamban and TuticorinThe islands have fringing coral reefs and patch reefs around themTotal area occupied by reef and its associated features is 94.3 sq km.

Reef diversity and resources

96 species of corals belonging to 36 generaThe most commonly occurring genera of corals areAcropora, MontiporaandPorites.the reefs also harbour boring sponges, molluscs, worms, echinoderms, common shrimps, and fishornamental fishes belonging to the familyChaetodontidae,(butterfly fish);Amphiprion spp(clown fish),Holocentrus spp(squirrel fish),Scarusspp (parrot fish),Lutjanusspp (snapper fish) andAbudefduf saxatilis(sergeant Major) are abundant. (Kumaraguru, 1997).

Extensive sea grass beds are present; green turtles, olive ridley turtles and dugongs are dependent on the sea grasses.

A unique endemic species of Balanoglossus, a living fossil that is considered a link between vertebrates and invertebrates was recorded from this region.

Annual productivity in coral reefs being 2000-5000 gc/sq.m/yr.

Sea Grass Ecosystem

the sole marine representatives of the Angiospermaefeeding grounds of the herbivores Green Turtle and the sea cowSea grass binds sediments and prevent erosion.Of the 52 species of sea grasses recorded worldwide, 12 species are recorded in Gulf of Mannar.Sea grasses absorb sediments thereby protecting coral reefs during storms and cyclones

Mangrove Ecosystem

salt tolerant forest ecosystems, which support fisheries and protect the coastal zones, thus helping the marine coastal economy and environment.9 species and 7 associated species were found in Gulf of Mannar.The two common mangrove species Rhizopora sp and Avecinia sp.

Dolphins are a common in some parts of the Gulf.Thousands of migratory olive ridley sea turtles pass through the Gulf to their mass nesting or arribada in Gahirmatha Orrisa.The Krusadai Island in the Mandapam Group of islands is of biological significance in this area due to its diversity.due to destructive fishing and pollution, coral reefs, dolphins, Dugongs (Dugong Dugon), whales and sea cucumbers are among the species which figure in the endangered list

Overall diversityFamiliesSpeciesPhytoplankton126Zooplankton360Forominifera51Sponges275Corals128Gorgonids14Polochaeta75Nematoda9Crustacea368Molluscus731Echinodermata264Hemichordata1Capture fishes441Ornamental fishes100Sea turtles5Sea weed147Sea grass52Mangroves16

Fishery ResourcesMarine capture fisheries are the major economic activity in Gulf of Mannar441 species have been recorded in Gulf of Mannar.(2,200 fish species distributed in Indian waters) Gulf of Mannar is one of the best regions in the Indian subcontinent in fish biodiversity richness. Shore seines, boat seines, trawl nets and hook lines are the principal gear operated.

Setusamudram

Advantages1.Saving of upto 30 hours or 424 nautical miles2. Considerable savings to vessels and earnings of foreign exchange.3. Beneficial for naval defence4. Increased economic activities like transportation, fishing and ancillary industriesAugmentation of external infrastructure like road/rail, water & water supplyA stable system with least maintenance cost

Sethusamudram Shipping Canal Project, a mega project involving close to Rs. 2000 crores involves the disturbance to delicate marine ecosystems of Gulf of Mannar Biosphere Reserve. The canal facilitates the direct approach of medium sized ships without bypassing through Sri Lanka to India. 14

Environmental Aspect

Some of the flora and fauna of this regionExtinction of more than 700 fish varitiesMore susceptible to future cyclone and tsunamisDisastrous effect on marine life, fisheries, virgin beaches in case of an accident Whether to go for short term financial gains or long term ecological balance ?

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Biodiversity of the Gulf Of Kutch

The Gulf of Kutch is situated in Saurashtra in the western State of Gujarat in India.separates the landmass of Saurashtra from the northern landmass of Kutch.shallow water basin about 60 m deep at the mouth, sloping up to a depth of less than 20 m at the head, visited by 'mixed semidiurnal' tides

1,650 km of Gujarat 17

Gulf of Kutch Marine National Park

It is the first national marine park in India.

situated on the southern shore of the Gulf of Kutch in the Jamnagar District of Gujarat state.

1980-an area of 270km2, from Okha to Jodiya was declared Marine Sanctuary.

1982-a core area of 110km2 was declared Marine National Park under the provisions of the Wildlife (protection) Act(1972)

Contd..

Protected areas include about an archipelago made up of 42 islands.

fauna found here: coral, dugong and the finless porpoise.

Biodiversity and Conservation challenges:

extraction of corals and sands by cement industries, increased turbidity of water, oil refineries, chemical industries and mechanized fishing boats.

Biodiversity Excellent Coral Reefs37 species of Hard & Soft Corals70 species of Sponges27 species of Prawns30 species of Crabs200 species of MolluscsEndangered Sea Turtles like the Green Sea, Oliver Riddley& Leather Back.3 Speices of Sea Mammals94 species of Water Birds78 species of terrestrial birds108 species of brown, green & red Algae

Coral Reefsfringing reefs, platform reefs, patch reefs and coral pinnacles. There are some 40 islands with patchy coral formation of which the largest is Pirotan Island.37 species of hard corals 12 species of soft corals the total reef area in the Gulf decreased from 217 sq km in 1975 to 123 sq km in 1986; a net loss of 43 per centCoral dredging by a cement company is held to be largely responsible for the heavy siltation

LocalityGeneraspeciesGulf of Kutch*2437West Coast Patches*1729Lakshadweep Islands37103Palk bay and Gulf of Mannar3696Tuticorin1921Andaman Islands3182Nicobar Islands43103

Total for India* 37 199Source: Bakus, G.J (1994) and * Pillai, G (1996).

coral

MangrovesJamnagar District has an area of 665.9 sq km mangrove coverpredominantly of scrubby and sparse typeMangrove species such as Rhizophora, Ceriops and Aegiceros, which are reported to have once existed in the region, are now rare, while the species Bruguiera is extinctSince the early 1990s, mangrove cover has been increasing in Gujarat, from 397 sq km in1991 to 960 sq km in 2003. - Jamnagar and Kutch - contributed to more than 90 per cent of the overall increase in mangrove cover.

Fisheries Jamnagar contributed 10.01 per cent of the total marine fish production in the State.W. Pomfret B. Pomfret Bom. Duck Thread fin Jew fish Hilsa Clupeids Coilia Shark

Malabar upwelling

Upwelling occur where the wind blows parallel to a coastline. divergence draws water from below into the surface Ekman layer in a process known asupwellingUpwelling in coastal waters brings nutrients toward the surface. Phytoplankton reproduce rapidly in these conditions, and grazing zooplankton also multiply and provide abundant food supplies for nekton. Some of the worlds richest fisheries are found in regions ofupwellingfor example, the temperate waters off Peru

Upwelling in these regions cools the surface water and bringsnutrient-rich subsurface water into the sunlit layer of the ocean, resulting in a biologically productive region.

The Malabar upwelling zone along Kerala coast (south-west coast of India) is one of the important upwelling systems of the world (Bakun et al., 1998)

The Malabar coast of India is rich in primary (660 mg C m2/ day) and secondary (1057 mgC m2 /day) production and contributes nearly 50% of the total Indian marine fish landings (Vivekanandan et al., 2003; Smith and Madhupratap, 2005)

Field and satellite-derived oceanographic data have shown that coastal upwelling occurs during JulySeptember with a peak in August resulting in high nutrient concentrations and biological productivity along the coast.

The striking feature of the Malabar upwelling zone is the predominance of pelagic resources such as oil sardine (Sardinella longiceps) and Indian mackerel (Rastrelliger kanagurta)

The catch of small pelagics, especially that of the oilsardine increased from1, 554 t in 1994 to 2,50, 469 t in 2007 in the Malabar upwelling zone off Kerala, India.

The coastal upwelling index (CUI) during south-west monsoon increased by nearly 50% during the period 1998 to 2007.

This substantial increase in coastal upwelling index elevated chlorophyll a concentration during monsoon which resulted in an increase of over 200% in annual average chlorophyll a concentration.

The increasing coastal upwelling index and chlorophyll a during monsoon sustained an increasing catch of oilsardine during postmonsoon season.

The responses of lesser sardine and Indian mackerel, which are midlevel carnivores, were different.

The prawn fishery is supported chiefly by Melapenaeus dobsoni (Poovalan chemmeen). Parapenaeopsis stylifera (Karikkadi chemmeen) and Penaeus indicus (Naaran chemmeen) also occur in smaller quantities. In the case of M. dobsoni, sizes ranging between 90-105 mm dominate in the fishery.

References Influence of coastal upwelling on the fishery of small pelagics off Kerala, south-west coast of IndiaU. MANJUSHA, J. JAYASANKAR, R. REMYA, T. V. AMBROSE AND E. VIVEKANANDAN

The Gulf of Kutch Marine National Park and Sanctuary: A Case Study By Nilanjana Biswas

Coastal an marine wetlands of India by K.Venkataraman

Resources information system for Gulf of Mannar Government of India

Environmental Impact Assessment for Proposed Sethusamudram Ship Canal Project Tuticorin Port Trust