Notes on the maturity and spawning of Opisthopterus tardoore (Cuvier)

The present study on the biology of Opisthopterus tardoore (Cuvier) was initiated in 1955 as part of the comprehensive investigation of the biology of the common clupeoids of North Kanara. Little is known about the fishes belonging to the genus Opisthopterus, excepting the post larval stages of Opisthoperus tardoore which have been described by John (1951). In view of this a detailed study of various aspects of the biology of this species was undertaken, and the present paper relates to notes on maturity and spawning of Opisthopterus tardoore, and incorporates the results of investigations carried out in the inshore regions at Karwar

A Ray-Tracing Model of the Vela Pulsar

In the relativistic plasma surrounding a pulsar, a subluminal ordinary-mode electromagnetic wave will propagate along a magnetic field line. After some distance, it can break free of the field line and escape the magnetosphere to reach an observer. We describe a simple model of pulsar radio emission based on this scenario and find that applying this model to the case of the Vela pulsar reproduces qualitative characteristics of the observed Vela pulse profile.Comment: 23 pages, 9 figures, accepted for publication in Ap

Observations on mackerel fishery at Karwar for the seasons 1954-55 and 1955-56

It has been pointed out (Panikkar, 1956), that the mackerel and the sardines together support a fishing industry of very high magnitude, employing several thousands of people, and unexpected large-scale fluctuations are a serious handicap to the full utilization of the fisheries. An exceptionally poor yield of mackerel was noted during the last two seasons. During the 1954-55 and 195.5-56 seasons the total catches dwindled to 951-2 and 508-3 tons respectively from the high peak of 2,250 tons in 1951- 52. Thus the mackerel fishery which has been considered the mainstay of Karwar fishery dwindled to a mere shadow of its former flourishing state in the last two years