[Show abstract][Hide abstract] ABSTRACT: A total of 200 specimens of oil sardine Sardinella longiceps collected from Kochi in the southwest coast and Chennai in the southeast coast were subjected to truss analysis. A truss network was constructed by interconnecting 10 landmarks to form a total of 21 truss distance variables extracted from the landmarks. The transformed truss measurements were subjected to factor analysis which revealed that there is no separation of the stocks along southeast and southwest coasts. The marginal differences in shape and form are attributed to the ecological differences in the habitats which are evident from differences in length weight relationships and feeding intensity of the population along these two coasts.
[Show abstract][Hide abstract] ABSTRACT: Climate change will have strong impact on fisheries with far-reaching consequences on food and livelihood of a sizeable section of the population. The frequency and intensity of extreme climate events is likely to have a major impact on future marine fisheries production. Fishermen have excellent knowledge on the relationship between climatic, oceanographic factors and fish catch. This knowledge enables them to switch their fishing activities with respect to species exploited, location of fishing grounds and gear used. Based on this backdrop, a survey was conducted to collect primary data on Indigenous Technical Knowledge (ITK) from 200 fishermen in and around Chennai with a structured questionnaire. Fishermen believed that reduction in fish catch in recent years is essentially due to overfishing (Garrett mean score : 82) and juvenile exploitation rather than climate change. Fishermen opined that current (62%) and wind direction/speed (28%) are the major climatic parameters affecting fisheries. Current from south to north direction which generally remains for nine months off Chennai leads to good fish catch, since it is favourable for larval distribution. They believe that combined wind blow from south and west leads to coastal upwelling, which occurs during May-June every year for 45 to 55 days. Current flow from south to north yields more rocky fishes due to turbid water condition and leads to heavy catch. However in recent years fishermen were not able to predict climatic events like in earlier years due to large unexpected seasonal variations. Fishermen suggested that government should bring regulations on craft, gear and related aspects in order to ensure sustainable fishing.
[Show abstract][Hide abstract] ABSTRACT: A total of 200 specimens of Indian mackerel (Rastrelliger kanagurta) were collected from Kochi in the south-west
coast and Chennai in the south-east coast and they were subjected to truss analysis. A truss network was constructed by
interconnecting 10 landmarks to form a total of 21 truss distance variables extracted from the landmarks. The transformed
truss measurements were subjected to factor analysis which revealed that there is no separation of the stocks along
south-east and south-west coasts. Thus the present study has indicated that the population of Indian mackerel from
south-east and south-west coasts remains the same.
Indian Journal of Fisheries 09/2014; 61(3):16-19. · 0.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The traditional knowledge is an excellent tool for understanding extreme events related to climate change. The Tamil Nadu fishers have extensive traditional knowledge related to climate change. Five hundred fishers were selected in different coastal villages by using of a random sampling method, and the data were analysed by using of Garrett’s method. The present study, the fishers opined that the wind seed and water current are the most important climatic factors for determining fish abundance and catch. These factors have undergone changes over the years. Water temperature changes indicate less fish catches, but when the warm water is present constantly, sardine fishes and seerfish catches are heavy. When the wind blows from southern direction they are able to predict the availability of squids. This preserved Indigenous traditional knowledge will be helpful for predicting climate variabilities related to fisheries.
Cultural landscapes, Indigenous Knowledge and Biotechnological Tools for Biodiversity Conservation, Coimbatore; 01/2014
[Show abstract][Hide abstract] ABSTRACT: Incidental capture of marine mammals in fishing gear is a major cause of concern. The International Union for Conservation of Nature (IUCN) identified bycatch as one of the serious threats to the marine mammals. The International Whaling Commission (IWC) estimated that at least 308,000 dolphins and porpoises are killed in bycatch every year in the world oceans. The Indian seas support 26 species of cetaceans and one species of sirenian. Until 2003, knowledge on marine mammals of India was restricted to incidental catch of different species in fishing gear. Between 2003 and 2012, the Central Marine Fisheries Research Institute (CMFRI) undertook a research project on marine mammals and conducted extensive visual sighting cruises onboard FORV Sagar Sampada in the Indian EEZ and contiguous seas to explore diversity, distribution and ecological characters of this mega fauna. The project also undertook a survey on the marine mammals that are incidentally captured by fishing gear. However, the extent of mortality caused due to fishing has not been properly documented so far. The available records are limited to a few beachcast specimens published occasionally in grey literature. The records that are available in the Indian seas for the last 200 years are consolidated in Table 1. The table does not show the number of marine mammals that had been caught so far, as the actual numbers must have been higher by an order of several magnitudes. Most of these records have stated that the capture is mainly by gillnets. In 2001, Government of India listed all marine mammals under Wildlife (Protection) Act. Under the act, capture and trade on marine mammals is punishable. This act has considerably reduced intentional capture of the mammals, but incidental capture still remains an issue. In 2007, the CMFRI estimated that 9,000 to 10,000 cetaceans are incidentally caught every year, mostly by gillnets along the Indian coast. .
Ecosystem approaches to the management and conservation of fisheries and marine biodiversity in the Asian Region, Cochin, Kerala, India; 10/2013
[Show abstract][Hide abstract] ABSTRACT: Shark fishing in India has, over the years progressed from "incidental" to "targeted." Sharks, which were predominantly landed as by-catch in different gears, is shifting from an artisanal coastal fishery towards oceanic targeted fishery, employing drift gillnets, hooks and line, and longlines operated from mechanized craft in recent years. Decades ago, artisanal fishermen in India conducted shark fishing in a sustainable way. Shark finning was practiced in the past, i.e., the carcasses were discarded after removing the fins. In recent years, the meat of sharks are in high demand in fresh, salted and dried form, particularly in the southern states of India and hence fishing for fins alone has stopped. In recent years, increase in demand for sharks in international markets, especially for fins, has encouraged directed fishing and expansion of fishing areas for shark fishery. In spite of attempts to increase production, the landing of sharks is on the decline indicating that their abundance is dwindling in the Indian seas. India is ranked second, next to Indonesia in shark landings, contributing about 9% to world catch in 2010. Time series landings data indicate that small-sized sharks have increased in the landings as opposed to larger sharks. Most of the sharks have biological characteristics typified by slow growth, delayed maturation, long reproductive cycle, low fecundity and long life span. Due to these disadvantageous biological characteristics, the sharks are vulnerable to overexploitation, and unplanned and indiscriminate exploitation could lead to population decline. Moreover, sharks occupy a position high in the marine food chain and their indiscriminate removal may alter the structure and function of the ecosystem. For sustainable management of sharks, the primary requirement is estimation of the status of shark stocks. Recent stock assessments and a number of studies in the Northwest Atlantic Ocean have found declines in many shark species (sandbar shark, dusky shark, hammerhead sharks, blacknose shark, porbeagle shark, shortfin mako shark, spiny dogfish etc.).
Ecosystem approaches to the management and conservation of fisheries and marine biodiversity in the Asia-Pacific Region”, 27-30 October, 2013,; 10/2013
[Show abstract][Hide abstract] ABSTRACT: The economics of fishery from artificial reef (AR) and non-artificial reef (NAR) sites by gillnet and hooks & line was studied during 2007-08 from 11 fishing villages in 6 coastal districts of Tamil Nadu. The Tamil Nadu State Fisheries Department fabricated and deployed the reefs under the technical guidance of the Central Marine Fisheries Research Institute (CMFRI). Based on species composition in the catch, the annual gross income was estimated by multiplying each species/group catch with the average landing centre price of the respective species/group. After deducting recurring expenditures on fishing operation, maintenance, interest on capital/investment on reef, crew wages, depreciation on craft, gear and reefs, from the gross income, the average net income of gillnet and hooks & line per unit operation from AR site werè1252 an4650, respectively; and from NAR site wa449 an1919, respectively. On an average, the AR site offered economic benefit which was higher b1705.9 per unit compared to NAR site. Hooks & line units performed better than the gillnet units in both the sites. The payback period towards repayment of AR establishment cost was only 0.21 year. In view of better economic viability and short payback period, deployment of artificial reef is recommended in the near shore waters with proper planning. Keywords: Artificial reef (AR) site, Catch per unit effort (CPUE), Economic benefit, Non-artificial reef (NAR) site, Payback period, Value per unit effort (VPUE)
[Show abstract][Hide abstract] ABSTRACT: In order to evaluate the impact of the interannual changes of upwelling on the small pelagics, the average chlorophyll a concentrations were compared with the fishery. The catch of small pelagics, especially that of the oilsardine increased from 1, 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 southwest 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 population increases of the oilsardine appear to replace decreases in the lesser sardines and Indian mackerel during the postmonsoon season.
Indian Journal of Fisheries 01/2013; · 0.22 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Seasonal fluctuations in the food of the oilsardine Sardinella longiceps landed by ring seines from the inshore waters off Cochin were studied during 2010. S. longiceps is chiefly a plankton feeder with diatoms, dinoflagellates and zooplankton appearing in the diet in decreasing order of abundance. During pre-monsoon (February-May), Pleurosigma was present in 70% of the stomachs analysed followed by Thalassiosira, Biddulphia and Coscinodiscus. During monsoon season (June-September), 87.5% of the stomachs contained Coscinodiscus followed by Thalassiosira and Pyrophacus. During post-monsoon (October-January) again, the frequency of occurrence of Pleurosigma (74.2%) was higher followed by Biddulphia and Thalassiosira. Zooplankton, represented by tintinnids and copepods, were present in the diet throughout the year, but in relatively less number of stomachs. Higher feeding activity was observed during monsoon (June-September), which coincided with maximum spawning activity.
[Show abstract][Hide abstract] ABSTRACT: Based on geographic features, the Tamil Nadu coast along the southeast coast of India can be divided into three systems, namely the Coromandel Coast, Palk Bay and Gulf of Mannar. Data on landed catches of all marine species, routinely recorded on a monthly basis from a total of 352 landing centres over the period 1995–2007, were examined for differences in species composition and numbers between the three regions and, specifically, for detectable effects of the Asian Tsunami of 2004. The average taxonomic distinctness (DELTA+) measure showed that the Coromandel Coast has distinct features with regard to taxonomic structure compared with the other two regions. However, neither this nor the variation in taxonomic distinctness (LAMBDA+) index were sensitive enough to reveal the effect of a natural disturbance such as the Tsunami. Simple measures of alpha, beta and gamma diversity were also not significantly different between the pre-Tsunami and post-Tsunami periods. In contrast, non-metric multi-dimensional scaling (MDS) ordinations displayed differences in species composition among the three regions and also some change in the years after the Tsunami. The latter was confirmed by analysis of similarities (ANOSIM) tests, with the clearest and strongest effects seen on the Coromandel Coast. It is inferred that the Sri Lankan land mass on the eastern side of the Gulf of Mannar and Palk Bay may have offered these regions a degree of protection from the Tsunami waves.
[Show abstract][Hide abstract] ABSTRACT: During the period 1998-2007, an annual average of 20,898 t of marine resources was landed by trawlers at Kasimedu, Chennai, by expending a mean annual effort of 35,608 units. The annual catch during 1998-2007 showed fluctuations between 12182 t in 2005 and 35,838 t in 2002. The mean annual effort of 13.21 lakh h in 1998 dropped down to 5.08 lakh h in 2007; mean annual catch declined from 36,364 t in 1998 to 17,293 in 2007. Catch per hour (CPH) increased from 27.51 kg in 1998 to 33.98 kg in 2007, in spite of reduction in both. Multiday trawl units which formed only about 8% of the annual operational units during 1989-'91, accounted for 39% and 31% of the operational units in 1998 and 2006, respectively. Seasonal abundance of catch indicated that maximum catch was landed during the third and fourth quarters of the year, which contributed to 34.2% and 25.1% of the annual average catch during 1998-2007. Demersal finfish resources contributed maximum (38.1%) to the annual average catch during the period 1998-2007 followed by pelagic finfish resources (25.4%), crustacean resources (15.1%) and cephalopods (5.6%). Miscellaneous finfishes and shellfishes accounted for about 15.8% of the catch. The resources that regularly contributed to the bulk of the catch were elasmobranchs,
[Show abstract][Hide abstract] ABSTRACT: Central Marine Fisheries Research Institute has collected and published information on occasional strandings, sightings and gear entanglement of marine mammals for more than 50 years from a vast network of trained field staff located at its research and field centres along the entire Indian coast. More than 85% of the publications on marine mammals in India are by the CMFRI. To create interest and awareness among students, researchers, naturalists and conservationists on marine mammals occurring in the Indian seas, the researchers of CMFRI have prepared species profile, which provides basic and interesting information on these charismatic animals. They have presented results of research projects on marine mammals and compiled available information from a large body of literature so that this publication serves as a source of ready reference to those interested on marine mammals. This publication will pave the way for producing a large number of marine mammalogists in the country to undertake advanced research on marine mammals in India and in the region as well.
[Show abstract][Hide abstract] ABSTRACT: Increase in sea surface temperature (SST) over the years is the primary indication of global worming. Temperature in turn affects other ocean parameters like salinity, pH, dissolved oxygen etc. All these factors have a synergistic effect on the biota, ranging from microscopic plankton to large fishes and marine mammals. As a prelude to understanding changes in biotic communities along the Tamil Nadu coast of India induced by alterations in climatic conditions, annual fish catch data of two major pelagic resources, the Indian oil sardine and the Indian mackerel, was correlated with SST data on SST were downloaded from the website of ICOADS (NOAA) following standard protocol. Three regions, Chennai, Nagapattinam, and Kanyakumari were selected for retrieving the SST data over the last 105 years (1905-2011). The data was sorted for four seasons (post monsoon, summer, southeast and northeast monsoon) and mean value and anomaly for each season of every 20 years was calculated for all three regions. Pooled data was used to arrive of a profile of the SST along Tamil Nadu coast. Available fish catch data (CMFRI) was tabulated along with SST correlation were studied.
There is a rise in SST over a period of 105 years. The increase in more perceptible in all four seasons for the past 20 years in all three regions selected. Rate of change in minimum and maximum SST in all at the 3 centre between the periods 1906-1925 and 1986-2010 was calculated. The trend shows an increase in minimum and maximum SST in all the seasons at Nagapattinam and Kanyakumari while at Chennai, minimum SST in SW monsoon season and maximum SST in summer season has decreased. The catches of oil sardine and mackerel show an increasing trend over the last 25 years. Seasonal analysis shows positive correlation of the catches with SST. The catch of oil sardine during summer months in particular showed an increasing trend over the period.
[Show abstract][Hide abstract] ABSTRACT: The fisheries management approach of several countries, including those in the Indian Ocean Region, has been generally on a species-to-species basis. It has been realized now that this ap- proach has severe limitations, especially for tropical, multispecies fisheries. While the under- standing that fish and other living aquatic resources are integral parts of their ecosystems is not new, this idea has not been put into practice in managing stocks, especially for marine fish. Re- shaping the management strategies by involving all the stakeholders in such an ecosystem ap- proach is expected to yield short-term and long-term benefits.
[Show abstract][Hide abstract] ABSTRACT: The Southern Ocean (SO) comprises more than 10% of the world's oceans and plays a substantial role in the Earth System. In total, it covers an area of 34.8 million km2. The shelves around Antarctica are on average 450 - 500 m deep, but exceed 1000 m in places. Of the total SO area. the continental shelf (~1000m in depth) covers 4. 59 million km2, the continental slope (1000 - 3000 m in depth) covers 2.35 million km2 and the deep sea (23000 m in depth) covers approximately 27.9 million km2 (Clarke and Johnston, 2003). Sea ice covers roughly half of the Southern Ocean during winter and approximately 10% during the summer.
Dr. S Jones Centenary Colloquium on 'Challenges in Marine Mammal Conservation & Research in the Indian Ocean, Marine Biological Association of India, Central Marine Fisheries Research Institute, India; 08/2011
[Show abstract][Hide abstract] ABSTRACT: Elasmobranchs comprising sharks, skates and rays have traditionally formed an important fishery along the Indian coast. Since 2000, Indian shark fishermen are shifting their fishing operations to deeper/oceanic waters by conducting multiday fishing trips, which has resulted in considerable changes in the species composition of the landings vis- a-vis those reported during the 1980's and 1990's. A case study at Cochin Fisheries Harbour (CFH), southwest coast of India during 2008-09 indicated that besides the existing gillnet-cum- hooks & line and longline fishery for sharks, a targeted fishery at depths >300-1000 m for gulper sharks (Centrophorus spp.) has emerged. In 2008, the chondrichthyan landings (excluding batoids) were mainly constituted by offshore and deep-sea species such as Alopias superciliosus (24.2%), Carcharhinus limbatus (21.1%), Echinorhinus brucus (8.2%), Galeocerdo cuvier (5.4%), Centrophorus spp. (7.3%) and Neoharriotta pinnata (4.2%) while the contribution by the coastal species such as Sphyrna lewini (14.8%), Carcharhinus sorrah (1.4%) and other Carcharhinus spp. has reduced. Several deep-sea sharks previously not recorded in the landings at Cochin were also observed during 2008-09. It includes Hexanchus griseus, Deania profundorum, Zameus squamulosus and Pygmy false catshark (undescribed) which have been reported for the first time from Indian waters. Life history characteristics of the major fished species are discussed in relation to the fishery and its possible impacts on the resource.
Indian Journal of Geo-Marine Sciences 06/2011; 40(3):347-355. · 0.29 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fisheries and aquaculture have very important roles for food supply, food security and income generation in South Asia. About
7.5 million people work directly in the sector in this region, producing around 8.5 million tonnes annually. Due to several
reasons, production from fisheries is stagnant in the last ten years, and aquaculture is not expanding as anticipated. Climate
change is projected to exacerbate this situation. The potential outcome for fisheries may be decrease in production and value
of coastal and inland fisheries, and decline in the economic returns from fishing operations. The potential outcome for aquaculture
may be higher capital, operating and insurance costs, loss of fish stocks, damage to facilities, conflict with other water
users, reduced production capacity and increased per unit production costs.
Despite the uncertainties and potential negative impacts of climate change on fisheries and aquaculture, there are opportunities
to reduce the vulnerability to climate-related impacts. The following measures could contribute to coping with climate change:
(i) evaluating the adaptive capacity of important fish groups; (ii) identifying adaptive fishing and post-harvest practices
to sustain fish production and quality; (iii) supporting energy efficient fishing craft and gear; (iv) identifying new land
use system for aquaculture; (v) identifying new candidate species and developing hatchery and grow-out technologies; (vi)
cultivating aquatic algae, which have positive response to climate change for food and pharmaceutical purposes and for production
of biodiesel; (vii) investigating the potential fish diseases in the natural and aquaculture systems; (viii) increasing climate
literacy among the fishing and farming communities; (ix) establishing Weather Watch Groups; and (x) evolving decision support
systems for fisheries and aquaculture in the region. It is also important to recognize the synergies between adaptive and
mitigation options related to climate change and non-climatic factors such as responsible fisheries, and ecofriendly aquaculture.
KeywordsFish production-Marine fish-Phenological changes and climate change-Corals-Iron fertilization-Sustainable fishing
[Show abstract][Hide abstract] ABSTRACT: Annual average fish landings along the east coast of India increased from 0.15 million tonnes during 1950-59 to 0.85 m t during 2000-06. The contribution of the northeast coast (NE) to the total landings along the east coast of India increased from 5.5% to 30.7% in the last five decades. There were remarkable differences in the catch composition between the NE and southeast (SE) coasts. Among the small pelagics, for instance, the hilsa shad Tenualosa ilisha and bombayduck Harpadon nehereus were dominant along the NE coast, but the oil sardine Sardinella longiceps, lesser sardines and Indian mackerel Rastrelliger kanagurta along the SE coast. Contribution of the fast growing, small-sized and low trophic level hilsa had increased from 0.5% during 1950-59 to 12.5% during 2000-06 along the NE coast, and the oil sardine (from 0.1% to 9.0%) and Indian mackerel (from 1.5% to 5.8%) along the SE coast. This has resulted in a decline in the mean trophic level of the catch by 0.077 and 0.041 per decade during 1950-2006 along the NE and SE coasts, respectively. This process of decline in the mean trophic level of the catch is caused due to substantial increase in the landings of species/groups that are low in trophic level, such as the small pelagics (oil sardine and hilsa), and penaeid and non-penaeid shrimps over the years.
Indian Journal of Geo-Marine Sciences 10/2010; 39(3):380-387. · 0.29 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The seasonal variability of phytoplankton biomass in the Arabian Sea, though a well researched topic, its inter-annual variability is less explored and understood. Analysis of the satellite-derived chlorophyll pigment concentration in the Arabian Sea during 1997-2007 showed a weak increasing trend. Contrary to the earlier hypothesis, our analysis showed that this increased phytoplankton biomass was not driven by the strengthening winds during summer monsoon. In fact, the basin-averaged chlorophyll concentrations during summer monsoon tend to decline, whereas those in September-October and during the winter monsoon showed an increasing trend. Based on the analysis of wind and aerosol optical thickness data, we attribute the increased phytoplankton biomass during September-October to dust-induced iron fertilization when there is sufficient buildup of nitrate in the upper ocean. During winter, the enhanced evaporative cooling under the strengthening winds led to the increased convective mixing. Subsequent supply of subsurface nutrients to the euphotic zone coupled with the increased dust delivery support the observed increase in phytoplankton biomass during winter