Data base development and computer applications in fisheries

Intensity of economic activity either in the established sector or emerging sector depends on the level of database of the sector. In the liberalised frame of Indian economy, established sectors such as agriculture have received a big boost resulting in higher production and larger earnings. Database for such sector is strong, built over years. However, there are emerging sectors which are highly productive and money spinning. Fisheries is one such sector having global perspectives. Database for this sector though available now in a limited dimension, is to be enlarged and strengthened for the benefit of entrepreneurs, industry, public enterprises, planners and administrators

A brief review of molluscan culture in the world

The oysters, mussels, clams, cockles, scallops and abalones are the food molluscs which are produced through aquaculture in several parts of the world. Oysters are among the earliest invertebrates produced by aquaculture and oyster culture dates back to the Roman days of 100 B.C. In spite of its antiquity application of modern technologies for the production of molluscs has been relatively recen

A simple model to test equal catchability of marked and unmarked animals in capture:-recapture studies

In capture-recapture studies it is generally assumed that both tagged and untagged ones have equal catch ability, No test however is available to verify this assumption. Rickerl has enumerated the effects of tagging and noted that these effects will in general be hard to detect. Darroch2 has pointed out the absence of such a test and stated "we hope to fill this gap at a later date". But it appears that this has not been done so far. Seber has also remarked the absence of such tests in general in concluding chapter of his remarkable book. Here we shall indicate a model, to detect the differential catchabilit

Studies on gill net selectivity

The theoretical models pertaining to the selectivity of gill nets proposed by Holt (1957) and Olsen (1959) are examined, especially with regard to the various assumptions inherent in the models. The validity of the models with respect to the validity of the assumptions has been tested. The selectivity of a gill net of a given mesh size as purely a function of the girth of fish alone is aiso critically examined

Characteristics of capture fishery resources, their assessment and management

There are two groups of factors, namely fishery independent factors such as current, temperature and salinity and fishery dependent factors such as types of fishing, namely trawling, gill netting etc. with different mesh sizes and intensity of fishing indicating the number of units of each type of fishing. Hence assessment of capture fishery resources remains a puzzle even today. However, attempts have been made to develop suitable mathematical and statistical models for assessing them and for offering suggestions for judicious management of the resources. This paper indicates in brief the important characteristics of the capture fisheries, their assessment and management with particular reference to India

Assessment of fish production in aquaculture

More than half of the world's population has an insufficient and nutritionally unbalanced diet. An adequate diet requires an average of about 44 g per day protein, being about 10 to 12 g of the total caloric intake. Fish is an excellent source of protein, containing all the 10 essential amino-acids in desirable concentrations for human beings and available at cheaper rates

Fishery Resources Assessment - A Challenge

Among the living resources, fishery resource in India plays a very dominant role in all facets of national development. Being a renewable and a very valuable resource it demands attention from all quarters for its rational exploitation and judicious management for reaping sustainable yields. The marine product exports in 1997 have almost reached the level of Rs. 4000 crores, a tremendous progress indeed! Thus having been established as an important foreign exchange earner, marine fish landings, however, fluctuates around 2.6 million tonnes per annum

A preliminary study of growth in Cerithidea (Cerithweopsilla) fluviatilis (Potiez and Michaud), (Prosobranchia-Gastropoda)

Observations on the growth of Cerithidea (Cerithideopsilla) fluviatilis in the Vcllar estuary have been in progress for over six months. Weekly samples were collected and linear measurements were recorded for a total number of 13,300 specimens. The samples showed unimodal frequency. The heavy aggregation of young on«s during July and August and the unimodal frequency distribution would indicate that there is only one breeding season in the year. In the interior parts of inlets and creeks during flood time and at other times also over-sized specimens above 23 mm. were observed whereas only large number of dead ones infested with crabs were noticed during flood time in the sampling area. This is apparently due to differential survival, the over-sized specimens taking shelter in creeks

A brief appraisal of marine fisheries in India

Using Relative Response Model and Maximum Contribution Approach, estimates on potential yield from the 0-50m depth area of Indian coastal waters are obtained as 2.20 and 2 00 million tonnes respectively. Basing on productivity estimates, potential yield from 50-200 m depth area is expected to be one million tonnes. It is suggested that no further increase in effort in 0>50 m depth is advisable. Instead, mechanisation of indigenous craft and/or replacement of existing small mechanised ones by medium sized vessels may improve the yield to 2.00 million tonnes. In the case of 60-200 m depth introduction of 400 large vessels of length above 10 m is suggeste

Application of Von Bertalanffy's growth model to Setipinna phasa (Hamlilton) when growth is allometric

A shape factor was introduced in the growth equation for S. phasa (Ham.) based on Von Bertalanffy's growth model and allometric growth. The estimates thus obtained fit the observed values better than those obtained with the assumption that growth is isometric. A new method of evaluating shape factor is described