Ecology of the cladocerans of the plankton community in the Cochin backwater

Occurrence and seasonal changes in the distribution of two cladocerans in the eochin Backwater, Evadne tergestina Claus and Penilia avirostris Dana have been considered. Fluctuations in temperature of tbe estuary are of the order of SoC., while tbe cbanges in salinity are considerable. Seasonal variation in distribution of tbe two species bas been correlated with temperature and salin ity in T-S-P diagram for a period of fifteen months. Their numerical abundance month-wise bas also been investigated. A comparative study of the distribution of cJadocerans of the insbore waters of India wilh that of the Cochin Backwater has also been carried out

Some Notes On Queenfishes And Their Fishery Along The Indian Coasts

A large variety of fishes popularly called horse mackerels, shads, trevellies, queenfishes, pompanos, runners etc. comprise the family Carangidae. Among them, the subfamily Scomberoidae represented by the genus Scomberoides (- Chorinemus) is popularly knownas queenfishes.They form an important constituent in the marine fish landings of India. This article highlights some of the taxonomic characters for easy field identification and also to review in brief the status of fishery of this group of fishe

Tidal influence on the diel variations of zooplankton with special reference to copepods in the Cochin Backwater

Diel variations of hydrobiological characters were studied during a complete tidal cycle at a station in the fishing grounds at the lower reaches of Cochin Backwater during November, 1969. The tidal oscillations and the resultant tidal surface currents were found to exert profound influence on these properties. The temperature of the surface water fluctuated depending on solar radiation, whereas, the salinity variations showed a direct relationship with the tides, recording high values during flood tide. Variations in zooplankton biomass appear to be partly influenced by the diel rhythm of plankters, and the incoming tides contribute to their increase during day time. Three broad types of distribution patterns were observed for the different groups of zooplankters depending on their relationship with the tides and diel vertical migrations. Fluctuations in copepod population in the estuary evinced a complex pattern of distribution and the ingress of neritic waters and the diel rhythm were the causative factors for the diel variations in their distribution

Some observations on the trend of zooplankton and Its probable influence on local pelagic fisheries at Colachel during 1973-74

The zooplankton standing crop showed three peaks of abundance, in March, September and December, the first two peaks during the periods of high salinity. In the order of abundance, the forms which constituted the bulk of the plankton were copepods, cladocerans, cirrepede larvae, Lucifer, chaetognaths and appendicularians. The copepod distribution was found to have characters common both to that of the adjacent coastal waters of Bay of Bengal on the southeast coast and to that of the Arabian sea on the southwest coast. The peak occurrence of cladocerans during May-July was followed by the appearance of juvenile mackerels in early August. Pelagic fish catch, consisting mostly of anchovies and lesser sardines, showed clear peaks, closely following the primary and secondary peaks of plankton. The peak occurrence of anchovies during September-October seems to be in prey-predator relationship with ribbonfish, the peak of which followed closely

Focus on small scale fisheries: drift gillnet fishery off Cochin, 1981 and 1982

In recent years, the drift gillnet fishery has become one of the fast growing fishing methods in the coastal fishing sector because of its economic viability and selectivity for catching larger pelagics which find ready acceptance and consumer demand in the market. The present report embodies the result of the study carried out on the mechanised drift gillnet fishery off Cochin, the cost-benefits of the operation and the drift gillnet operations are confined to the surface and mid-depth zones at the fishing grounds, a brief review of the hydrographic features of the area during the period 1981 and 1982 is presented here

Observations on the fishery and certain aspects of the biology of yellowfin tuna, Thunnus albacares (Bonnaterre) taken by longline gear in the EEZ of India

The two oceanic species of tunas that are exploited by India at present are the skipjack and yellowfin (mainly young ones) tunas. The distribution of yellowfin tuna in the area extends from the oceanic waters to the marginal range of neritic provinces, and the exploitation of this species is chiefly along the fringe of its distribution. In the case of the yellow fin tuna, the juvenile and immature fishes enter the surface fishery in the insular ranges and the adults are mainly confined to the sub-surface waters in the oceanic area where they contribute to the tuna longline fishery

Fishery and bionomics of tunas at Cochin

As stated earlier, the Central Marine Fisheries Research Institute furnishes the production figures of various species of marine fishes based on multistage stratified random sampling techniques. For detailed biological investigations involving aspects of species composition, size, age, growth, spawning, maturity, food and feeding habits and other parameters, the Project has selected some important centres for tuna investigations which would help in monitoring the resources. The fishery and biological aspects collected from 6 centres viz., Mangalore, Calicut, Cochin, Vizh'njam and Tuticorin in the mainland of India, and from Minicoy in the U.T. of Lakshadweep are analysed and results presented in the ensuing section under different modules

Population dynamics of tunas : stock assessment

Crafts and gears employed in the fishery and the system of collection of data at different centres along the west and east coasts in the mainland of India and from Minicoy Is. were dealt with earlier. In the manner described, the following informations were collected : — Numbers landed by fishing gear ; — Estimated total tunas landed by weight by fishing gear; — Estimated weight of sampled landings ; — Species composition of sampled landings, and — length and weight of tunas in sampled landing

Not Available

Not AvailableOccurrence and seasonal changes in the distribution of two cladocerans in the eochin Backwater, Evadne tergestina Claus and Penilia avirostris Dana have been considered. Fluctuations in temperature of tbe estuary are of the order of SoC., while tbe cbanges in salinity are considerable. Seasonal variation in distribution of tbe two species bas been correlated with temperature and salin ity in T-S-P diagram for a period of fifteen months. Their numerical abundance month-wise bas also been investigated. A comparative study of the distribution of cJadocerans of the insbore waters of India wilh that of the Cochin Backwater has also been carried out.Not Availabl