2,360 research outputs found
Is there over-fishing in Indian waters?
In view of the vast expanse of the sea it was believed
that the resources of the sea are almost inexhaustible
and ,ve can put in more and more fishing effort
to get higher and higher yield. Sufficient evidence
has, however, been accumulated to show that this
belief is not true. With the advent of steam trawling,\ud
several nations began intensive fIshing in the North
Sea towards the end of the nineteenth century and this
resulted in rapid decline in the abundance of most of
the species
A note on the production trend of marine shrimps in India
The paper reviews the production statistics of marine shrimps
in the different maritime states of India from 1950 to 1962. It is pointed
out that for a correct appraisal of the status of any fishery, it is
necessary to have data on effort E and catch per unit effort in addition
to the conventional data on catch C. A relationship between U and E
has been developed and the status of the fishery of Metapenaeus dobsoni
has been discussed in this connection with reference to the data on
catch and effort obtained from trawler operations off Cochin
Fish Population Studies
Generally, we hear such questions as "what is the magnitude of our oil sardine or
mackerel resources?" "Can we get more catch from these resources?" It is, therefore,
proper that we carefully examine what is meant by a fishery resource e. g., oil sardine or
mackerel resource. A fishery resource is just like any other natural resource (e. g., mineral
resource, hydro-electric resource etc.) which is exploited by man. But at the same time,
it differs considerably to character from other types like mineral resources. The coal resource
in a region is limited in magnitude, even though sometimes we do not know the
magnitude. From this fixed resource we can exploit at any desired rate. The resource will
be completely exhausted after a period of time depending on the rate of exploitation. In
this sense a mineral resource can be described as a non-renewable natural resource which is
liable to get exhausted after some period of time. It is also a static resource because we
always know how much of the resource remains, once we know how much has been removed.
A fishery resource is very much different in character. It is a self-regulating renewable
natural resource. Consider a fish population occupying a certain area of the sea. Now
when a certain portion of the population is removed, the remaining portion in the habitat
gets better food, more area to move about, and this results in faster growth rate, lesser
mortality rates and also the spawns get better chance of survival- The result is that the
resource resuscitates itself quickly. Apart from fishing, the population is also affected by
many other fishery-independent environmental factors such as available food supply, change
in salinity, temperature of the water, change in ocean-currents etc. Thus the fishery resource
is a dynamic resource, ever changing due to impact of fishing and other fishery-independent
factors
The Indian mackerel; V Population
Pradhan (1956) examining the mackerel landings at Karwar from 1948-49 to 1952-53 concluded
that the sex composition of the commercial catches during the fishing season was roughly as 45% male
and 55% female. Similar qualitative statements regarding sex distribution of commercial landings at
various specific centres are available in the annual reports of the Central Marine Fisheries Research Institute.
In 1965-66, the sex ratio studies at Cannanore indicated that the proportion of males was slightly
higher than females (53.18:46.32) in the adult population. The predominance of males was
also seen in Juveniles (modal size 135 mm). In the medium sized fish (modal size 205 mm) which
contributed to the bulk of the catch, the sex-ratio was in the reverse order (40.7M;59.3F). In the same
year, at Cochin females dominated the catches except for April and September (Central Marine
Fisheries Research Institute Annual Report 1966). In 1966-67 season, the sex ratio during the
fishing season was found to vary though in some centres was almost equal (Cenrtal Marine Fisheries
Research Institute Annual Report 1967). In the first half of 1967-68 season, the sex-ratio of
a sample analysed at Karwar showed that females were more numerous. At Mangalore, males
were more numerous in the aggregate. Sexes were almost equally represented at Cochin and Cannanore.
At Vizhinjam males were predominant in March. In the second half of the year, at Cannanore
the females increased to more than twice that of males (Central Marine Fisheries Research Institute,
Annual Report 1968). The above excerpts will show that there is no uniformity in the sex distribution in the
commercial catches either among various centres or between various fishing seasons. In the absence of
Functions of a Fishery Data Centre
In the modern world. no government or b usiness house can funct ion properly without recourse to a wide variety of statistical informa,ion at its disposal. The statistical data constitute the quantitative information based on which development plans or expansion programmes are drawn up
Kinetics & Mechanism of Chloramine- T Oxidation of ɑ-Hydroxy Acids in Perchloric Acid Solution
615-61
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