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Fish Population Studies

By S K Banerji

Abstract

Generally, we hear such questions as "what is the magnitude of our oil sardine or\ud mackerel resources?" "Can we get more catch from these resources?" It is, therefore,\ud proper that we carefully examine what is meant by a fishery resource e. g., oil sardine or\ud mackerel resource. A fishery resource is just like any other natural resource (e. g., mineral\ud resource, hydro-electric resource etc.) which is exploited by man. But at the same time,\ud it differs considerably to character from other types like mineral resources. The coal resource\ud in a region is limited in magnitude, even though sometimes we do not know the\ud magnitude. From this fixed resource we can exploit at any desired rate. The resource will\ud be completely exhausted after a period of time depending on the rate of exploitation. In\ud this sense a mineral resource can be described as a non-renewable natural resource which is\ud liable to get exhausted after some period of time. It is also a static resource because we\ud always know how much of the resource remains, once we know how much has been removed.\ud A fishery resource is very much different in character. It is a self-regulating renewable\ud natural resource. Consider a fish population occupying a certain area of the sea. Now\ud when a certain portion of the population is removed, the remaining portion in the habitat\ud gets better food, more area to move about, and this results in faster growth rate, lesser\ud mortality rates and also the spawns get better chance of survival- The result is that the\ud resource resuscitates itself quickly. Apart from fishing, the population is also affected by\ud many other fishery-independent environmental factors such as available food supply, change\ud in salinity, temperature of the water, change in ocean-currents etc. Thus the fishery resource\ud is a dynamic resource, ever changing due to impact of fishing and other fishery-independent\ud factors

Topics: Population Dynamics
Year: 1967
OAI identifier: oai:eprints.cmfri.org.in:5551

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