Central Island Agriculture Research Institute
Important Announcements:


FisheriesScience

 

Coastal Bio-resources Management

 

  • The Nicobar group of Islands are highly vulnerable to climatic variation due to their flat topography, limited physical size and geographical isolation. Among the Nicobar Islands, Trinket and Chowra have over 15% of the total land area with an elevation less than 10m above MSL. The digital elevation data taken together with the population density of different islands in the Nicobar district showed that Chowra is the most vulnerable island to climate-associated disasters. The agricultural vulnerability map of Car Nicobar prepared based on multiple parameters indicated that about 20% of the area in Car Nicobar has high to very high vulnerability to climate change.

  • The projected changes in mean temperature and precipitation using the MAGICC/SCENGEN software indicate that the rainfall pattern is all set to change significantly (P<0.05) during different seasons and the pattern of change in Nicobar would be different from that in Andaman.

  • Under a collaborative project with Space Application Centre, Ahmedabad, contributed in determining the extent of coral reef area in A&N Islands (1021.5 sq.km). Species distribution in Marine National Parks (MNP) and popular dive sites have been documented.  Periodic surveys conducted to assess the reef health across different islands in Andaman indicated that the reefs suffered extensive bleaching (upto 70%) during May 2010 due to elevation of sea surface temperature. Anthropogenic disturbance of the reefs leading to polychaete infestations and reef mortality was also described.

  • Developed spectral signatures for different forms of corals and delineated their potential use for differentiation of coral forms and species in some cases through underwater radiometer surveys in Andaman.

  • The biodiversity of marine sponges from North Bay and Pongi Baalu has been documented. Altogether 51 marine sponges were collected and described through conventional taxonomy (17 of them are new locational records for India). Through a study on the bioactivity of marine sponges 10 sponges and 75 sponge associated bacteria with significant bioactivity were identified and characterized.

  • 34 true mangrove species belonging to 15 genera, 10 orders and 12 families have been documented and 25 species, one of which is a new locational record for the islands were fully described.

  • Trophic level productivity measurements within different areas, coral reefs, , mangroves, coastal and open sea have been done along with spatial and temporal patterns of different water quality parameters and their relation to aquatic fauna. The average gross and net primary productivity of Andaman coastal waters were found to be 298.33 and 115.27 mg C/m3/ha respectively.

 

Capture fisheries

 

  • Under a collaborative project with INCOIS, three Digital Display Boards have been installed in Andaman to disseminate details on fish availability, weather conditions and tsunami warning. The study showed that by following the Potential Fishing Zone (PFZ) advisories, the catch per unit effort (CPUE) shall be increased by 34% and scouting time shall be reduced by 51%. By following the PFZ advisories, an average increase of 30.37 ± 2.27%, 30.03 ± 2.15% and 23.80 ± 1.30% in total catch was observed by gillnetters, trawlers and longliners respectively. The cost benefit ratio for each class of vessel was 2.70 for gillnetters; 3.47 for trawlers and 3.26 for longliners against their respective control group of fishers (1.68, 1.50 and 1.81). A total of 60 PFZ awareness campaigns were held across the islands wherein over 600 fishers were sensitized.

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  • A systematic analysis of landings of groupers and snappers in South Andaman revealed that the average annual catch per unit effort (CPUE) was 130 kg/boat, with maximum CPUE (186 kg/boat) being recorded in September, 2010. Among groupers, Epinephelus malabaricus and among snappers, Lutjanus gibbus were the predominant species. In case of Epinephelus malabaricus, major size classes of landings were found to be between 25-40 cm which indicates “growth overfishing” and the need for proper fishing regulation for sustainable harvest of the resource.

 

Aquaculture

 

  • The feasibility of cage culture of groupers in protected bays and creeks in Andaman was assessed using wild caught seeds. The grouper stocked at the size of 201.73 ± 27.57 mm and weight 90.06 ± 41.40 g recorded a growth of 79% in six months with 97% survival. The study demonstrated that the cannibalism and crab infestation in the cages can be checked through proper site selection and feeding management. The bottleneck for the adoption of the technology were issues related to seed supply, access to live fish market and logistics required for live fish trade.

  • An integrated mangrove-based agro- aqua farming system was developed at Sippighat Brackishwater Farm complex of CIARI and at a farmers’ field at Indira Nagar. More than 150 farmers were sensitized on the potential of mangrove-based aqua farming in the islands. Two farming system patterns- pond-based brackish and fresh water farming systems have been demonstrated to the island farmers.

  • The Cheekspine anemonefish, Premnas biaculeatus has been successfully bred in captivity and details of embryonic development from egg to hatchlings have been recorded. The larvae (3.724 ± 0.05 cm) after hatching were active swimmers and started feeding on rotifers after yolk absorption (12-24 h). The breeding technology has been included in the Micro-Business Module published by the institute. The major live feed supplement for damsels is the rotifers and their distribution and abundance (7 species) in the islands was explored and documented.

  • A catfish hatchery has been established at CIARI and the seed production and larval rearing technology of cat fish (Magur) has been standardized successfully with a survival of 60% under controlled conditions.

  • A study on the incidence of white spot syndrome virus (WSSV) in the wild stock of tiger shrimps in Andaman indicated that about 30% of the wild tiger shrimps are carriers of WSSV, the most devastating disease known to shrimp aquaculture.

  • An exhaustive survey on the tsunami affected areas was carried out delineating ideal areas for brackish water aquaculture in collaboration with CIBA, Chennai and A&N Administration under the aegis of Coastal Aquaculture Project Implementation Committee.

 

Freshwater aquaculture

  • Backyard hatchery for Freshwater prawn (Macrobrachium rosenbergii) has been developed at CIARI. Seed were being produced in hatchery and regularly distributed to the farmers of South Andaman.

  • Magur hatchery has been set up for the first time in Andaman and Nicobar Island. Magur seed were produced and maintained at the newly constructed hatchery. In order to cater to the needs of catfish seeds in the Islands, a magur hatchery has been developed at CIARI. The cat fish larval development unit has been developed wherein breeding of magur has been carried-out successfully with a survival of 60% under controlled conditions.

  • Salinity tolerance study was also conducted in Clarias batrachus to explore the possibility of culturing them in slightly saline areas.  It was observed that fishes grow better at 0 ppt salinity.  Mortality rate of magur was highest at 8 ppt salinity (16.7%). Studies on biochemical parameters revealed that most of the parameters like ascorbic acid, blood glucose and liver glycogen levels were reduced drastically at 8ppt.

Brackishwater aquaculture

  • Post tsunami survey was conducted to identify the potentially cultivable area,   revealed that approximately 4000 ha areas of agricultural farmlands have been submerged, out of which 630.12 ha of area were suitable for coastal aquaculture purpose.

  • Growth studies of Liza tade was tried in different salinity and found that the overall growth was not very encouraging in this in the laboratory condition. Maximum growth in terms of weight gain was recorded at 15 ppt salinity followed by 10 ppt salinity.

  • Survey on mangrove area showed that 30-80% mangrove stands have got affected in South Andaman due to earthquake and tsunami during 2004. In Middle Andaman the impact is negligible whereas in North Andaman due to elevation of land, the seawater is not reaching some of the mangrove. Survey in Shoal Bay area of South Andaman indicated that Rhizophora apiculata account is the dominant species (43.6%) followed by  Rhizophora mucraonata  (15.0 %) and Ceriops tagal  (13.3%). Studies on mangroves in and around Shoal Bay and Porlob Jig under coastal zone studies was investigated and found that Rhizophora apiculata ( 27.35) was dominated in Shoal Bay area and Ceriops tagal ( 38.2%) in Porlob Jig.

  • An Integrated farming system based on brackish water aquaculture, incorporating components of horticulture, medicinal plants and poultry has been attempted. Tiger prawn seeds (PL-20) produced from Andaman mother shrimp at this institute. At the farmer field with zero management practice, tiger shrimp has been cultured and marketed.

  • Incidents or prevalence of white spot disease in Andaman waters was investigated through PCR. It was found that infection rate was 17.77% in 2007, and 36% in 2006. From the studies, it was found that infection rate of WSSV in tiger prawn Penaeus monodon and Banana prawn, Ferropenaeus merguensis in Andaman is mild.

Mariculture

  • Successfully completed cage culture experiment in Andaman waters.  From the study 79.17% growth rate within six months with 96.81% survival was achieved from the study. Successive culture experiments suggested that the cannibalism in the groupers could be checked by resorting to proper feeding.

  • Breeding techniques of damsel fish, Premnas biaculeatus has been successfully bred in captivity and details of embryonic development from egg to hatchlings were recorded and photographed. Live feed like rotifers have been used for feeding the fishes. The larvae after hatching were active swimmers and started feeding on rotifers after yolk absorption (12-24 h).

  • The brown algae, Nanochloropsis oculata was found to be a better feed than the green algae, Chlorella marina to the rotifers, which constitute the major live feed of marine ornamental fishes. The algal density required for maintaining the desired density of rotifers and copepods in the finfish hatchery was determined.

  • A total of 20 species of grouper and 5 species of snapper have been identified from landing centers. Efficacy of fish flesh, mussel meat, chicken waste and mixed feed (equal percentage of all other feeds) on Cephalopholis microprion has been tried and found that mussel meat gives the best result followed by fish flesh.

Resource assessment studies

  • A survey on the wild catch of Groupers and Snappers in various landing centres in South Andaman indicated that grouper landings are significant in Wandoor and Guptapara. Among groupers, Epinephelus malabaricus and among snappers, Lutijanus gibbus were the predominant species. A systematic analysis of landings of groupers and snappers in South Andaman revealed that the average annual catch per unit effort (CPUE) was 130 kg/boat, with maximum CPUE (186 kg/boat) being recorded in September, 2010.

  • Cataloguing of 42 species of ornamental reef fishes from North Bay area has been done. RAPD finger printing between freshwater and brackish water Tilapia species has been attempted and revealed typical cluster at 73% similarity level in the dendogram. It is evident that fishes are thriving in both the environments with a similar genetic makeup with a difference of only 6% as envisaged in the present sampling and primer usage.

  • Studies on the temporal variation in water quality parameters indicated that the primary productivity of Andaman waters progressively increased from June 2008 to Feb 2009. The average gross productivity, net productivity and respiration requirement were 321.1 , 125.6 mg C/ m3/ h and 12.8 mg C/ m3/ h respectively.

  • An exploratory survey on the habitat of top shell, Trochus sp indicated that its normal habitat consists of dead corals and algae (23.57%), dead corals (19.3%), live corals (19.5%), rock and rubbles (14.28%), sand (12.93%), soft corals (4.01%) and other components. Percentage distribution of, Trochus niloticus  species is more in Boat Island followed by Chidyatappu. T. niloticus is found in near shore areas as well as in the coral reefs areas.  Along with the Trochus sp various other gastropods and coral reef fishes are also recorded which in turn form a part of the habitat of T. niloticus.

  • PFZ advisories have proved to be a potential tool in harvesting under-exploited fishery resources with a significant increase (34%) in CPUE of fishing vessels in the A&N Islands. Validation experiments employing different vessels viz., gillnetters, trawlers and long liners showed an average increase in total catch of 37±1.8%, 34±1.24% and 30±1.36% respectively.

Cataloging and characterization of marine resources

  • The coral reef biodiversity and mangrove biodiversity of the A&N Islands were documented and a field guide for the identification of mangroves of A&N Islands has been published.

  • To study the distribution and abundance of corals of Andaman, the line transect survey was employed using topographic satellite maps. There were 192 species of coral under 57 genera in 15 families were recorded from Andaman and Nicobar during the period 2004 – 2006.

  • Periodic surveys conducted to assess the reef health across different islands in Andaman indicated that the reefs suffered extensive bleaching (upto 70%) during May 2010 due to elevation of sea surface temperature. The bleached reef associates have fully recovered, massive corals are recovering while all the affected branching corals (Acropora sp) were dead.

  • Altogether 51 marine sponges were collected of which 27 have been described through conventional taxonomy. Antimicrobial assay of host vis-à-vis the associated bacteria was carried out for eight sponges. The bioactivity of Pseudoceratina purpurea, was predominantly due to host metabolites, while in all others the associated bacteria displayed higher inhibitory bioactivity than their hosts.

  • Two marine sponges Stylissa sp and Iricinia sp collected from North Bay, South Andaman were studied for their antimicrobial properties against selected pathogenic bacteria. About 70% of the isolates associated with Stylissa sp werefoundtoproduce antibiotics and one of them was about 120% as effective as erythromycin against Klebsiella pneumonia.

  • Four sponges collected from Pongibaalu viz., Crella cyathophora, Oceanapia sagittaria, Plakortis sp and Monanchora sp were studied for their antimicrobial properties against selected pathogenic bacteria. Qualitative dual culture assay revealed that in case of Oceanapia sagittaria and Monanchora sp, the antimicrobial activity was primarily due to the host metabolites. In Crella cyathophora and Plakortis sp., over 75% of the associated bacteria exhibited significant (P<0.05) antimicrobial activity against the selected pathogens.

  • To assess the climate change threats in Nicobar Islands,  agricultural vulnerability map of Car Nicobar was prepared based on multiple parameters viz., elevationabove mean sea level, estimated sea level rise of 0.3-0.5m, soil quality/depth and land-use pattern. It was observed that about 20% of the area in Car Nicobar has high to very high vulnerability to climate change as predicted globally. The soils in these islands are generally medium in available N (4.47-7.19 kg/ha) and low in available K (115-194 kg/ha), which imply that climate change-induced increase in rain fall or seawater ingression would lead to soil erosion, leaching of salts and salination of coastal lands thus rendering the soils unproductive for agriculture.

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