Maturation of the intra-ovarian eggs and the spawning periodicities in few fishes of Mangalore area based on ova-diameter measurements

Ova-diameter studies have become an integral part of fishery biological research. It is well known that in most fishes there is a marked seasonal periodicity in egg production. Clark (1934) and Hickling and Rutenberg (1936) have shown that it is possible to determine the time of spawning and the spawning periodicity of fishes by ova-diameter frequency studies. Karandikar and Palekar (1950, 1952 and 1953), Prabhu (1956), Dharmamba (1959) and Karekar and Bal, (i960) among others have shown that this method is applicable in regard to the fishes they studied. This account deals with the determination of the time and periodicity of spawning of four common food fishes of the South Canara coast viz., Nematalosa nasus, Anodontostoma chacunda (Family Clupeida.e); Otolitkus argenteus (Family Sciaenidae), and Saurida tumbil (Family Scopelidae), based on the frequency distribution of the diameter of the intraovarian eggs