Feeding and reproductive biology of Saurida undosquamis (Richardson, 1848) from Parangipettai coast, Southeast coast of India.
The feeding biology, spawning season, size at first maturity, sex ratio and fecundity of the commercially important lizardfish (Saurida undosquamis) were studied in Parangipettai waters of the southeast coast of India. Fishes formed the predominant food item. Diversity of the prey items showed maximum value (H'log 2-3.61 +/- 0.11) during the postmonsoon season and minimum during the monsoon season (2.89 +/- 0.17). The richness (1-lambda') also showed a similar trend and varied from 0.81 +/- 0.13 (monsoon) to 0.91 +/- 0.01 (postmonsoon). The size at first maturity (50% incidence of mature fish) was 195 mm. But when the size at first maturity was calculated by adjusting the proportion of maturity percentages, the maturity size was found to be 140 mm. This method is advantageous from the point of view of fisheries management as this species can be exploited above 140 mm rather than above 195 mm. The gastrosomatic index was found maximum during postmonsoon and minimum during the monsoon season showing the inverse relationship between feeding and spawning. This species was found to spawn from August to January with a peak in November. The fecundity ranged from 19, 856 in a fish measuring from 20.1 cm in length (97 g) to 79,282 in a fish of 29 cm (290 g). The overall sex ratio (1:1.19) was found to deviate significantly from the expected 1:1 ratio. (chi2 = 19.1, p < 0.005). Month- wise, it conformed to the expected 1:1 ratio during most of the months except January, June, September, November and December. Higher gonado-somatic index values observed during October-December suggested spawning activity during this period. This species is found to a total spawner in the Parangipettai waters.
Parasitic fauna of the marine greater lizard fish Saurida undosquamis (Richardson, 1848)
Through examination of 125 specimens of the marine greater lizard fish Saurida undosquamis (Richardson, 1848) obtained from Zagazig fish market and its source from Gulf of Suez, the overall prevalence was 44.8%. The parasitic fauna was composed of Acanthocephala; Serrasentis sagittifer (prevalence: 12.8%), Cestoda; Oncodiscus sauridae (prevalence: 5.6%), Nematoda; Echinocephalus species larvae (prevalence: 4%), female of Philometra species (prevalence: 13.6%) and Trematoda; Lecithochirium grandiporum (prevalence: 16%) and juvenile didymozoid; Neotorticaecum (prevalence: 2.4%). The most prevalent parasitic fauna was nematodes followed by trematodes then acanthocephala and cestodes. The detected parasitic fauna was morphologically described by light microscope.
The breeding and fecundity of the Long Rough Dab Hippoglossoides platessoides (Fabr.) and the associated cycle in condition
Details are given of the breeding biology, including the fecundity, of the Long Rough Dab deduced from samples taken in the Clyde Sea area from October 1953 to April 1955. Where possible breeding is related to the condition of the fish; the index of condition is based on the length-weight relation. The weight of Long Rough Dabs of each sex and stage in maturity increases as a power, slightly greater than the cube, of the length. An annual cycle of fluctuations of this power is seen in the immature females, and indicates how changes in condition at different seasons affect the different size-groups. The measure of condition is taken as the expected weight of a 20 cm Long Rough Dab, and the changes in this weight are followed through the sampling period for males and for immature, maturing and spent females. All groups tend to be in best condition during November and December followed by a decline to the spawning time, in March and April, after which there is a slow recovery.