Molluscs in Indian tradition and economy

The molluscs constitute a natural resource of sizeable magnitude in many parts of the world. They are an age old group represented among the early fossils, a group of great diversity in size, distribution, habitat and utility. The range of their distribution is as extensive in space as in time for it covers terrestrial, marine and freshwater habitats. They include members from the tiny Estuarine gastropod Bithynia and small garden snails to the Giant Clam Tridacna or the Giant Squid Architeuthi

Some special features of catfish fisheries for consideration in developmental programmes

There are some aspects of the catfish biology and behaviour that are significant from the point of view of exploitation and which, by the same token, make the fish vulnerable to indiscriminate fishing at the juvenile and spawner stages

Plankton of Calicut inshore waters and its relationship with coastal pelagic fisheries

Studies on the inshore plankton of Calicut waters and on the related hydrological featuies have been made in earlier years, and there have been attempts, in general terms or specifically, at correlating these with the fisheries of the area. From Homell and Nayudu (1924) who suggested that the oil sardine might be coming into the inshore waters to feed on the plankton there, various workers have followed this view. Particular mention may be made, in this regard, of the observations of Chidambaram and Menon (1945) who arrived at a positive correlation between the plankton and the pelagic fisheries of this area during the post-monsoon period; of George (1953) who demarcated the inshore plankton as "edible" and "non-edible" from the point of view offish food and marked the fact that the fishery season along the coast coincided with the period of abundance of "edible plankton", suggesting close relationship between the two; of Subrahmanyan (1959) who discussed the relationship of plankton production with fluctuations of oil sardine and mackerel landings on a month-to-month basis, finding broad correlation between standing crop of the plankton and total quantity of fish landed. A specific food-relationship between the juveniles of the oil sardine and the diatom Fragilaria oceanica was suggested by Nair and Subrahmanyan (1955) with a possible effect on the sardine fishery of the area. Subrahmanyan (1959) while confirming this, found no such relationship between the mackerel and any other specific factor

General features of the catfish fisheries

Catfishes had formed significant seasonal fisheries along the west and east coasts of the country since the early artisanal days, but had seldom been viewed as anything more than of local importance. The traditional gears were mostly aimed at pelagic fisheries and caught demersal species by the way when they fished in shallower coastal areas and the gear took in the bottom layers also. So the ground fish contribution to the country's total marine fish landings was small. Thus, in the earlier years of our concern with the assessment and development of marine fisheries, the sardine and mackerel fisheries easily caught the attention as national fisheries, and the prawn fisheries rapidly turned into an export-oriented industry and assumed tremendous importance as a foreign-exchange earner. Many others, potentially significant, tended to be passed over, and the catfish fishery was among them

The catfish resources

widely distributed in the tropical Indo-Pacific and they constitute a regular, sometimes dominant, component of the demersal fish landhigs along the Indian Coast. Species of the genus Tachysurus contribute nearly 99% of the catfish catch, particularly T. thalassinus. T. tenuispinis, T. serratus and T. dussumieri. Osteogeneiosus militaris also forms a fishery along the northwest coast

Investigation of optimization of attitude control systems, volume i

Optimization of attitude control systems by development of mathematical model and computer program for space vehicle simulatio

Investigation of optimization of attitude control systems, volume ii

Attitude control system optimization - computer programs, listings and subroutine

A note on the food of young mackerel

THE food of the Indian mackerel, Rastrelliger kanagurta (Cuvier), has been investigated in some detail but the studies have largely been based upon samples of higher size-groups. Not only is the information available on the food of young mackerel limited, but there is also no agreement among the workers on the nature of their food