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Subject: Fisheries Resource Management × Author: AISHWARYA C. H., × Start date: 2006 ×
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    ThesisItemOpen Access
    “STUDIES ON SOME ASPECTS OF BIOLOGY OF THE RED SPOTTED SWIMMING CRAB, PORTUNUS SANGUINOLENTUS (HERBST, 1783) OFF MANGALURU COAST”
    (KARNATAKA VETERINARY, ANIMAL AND FISHERIES SCIENCES UNIVERSITY, BIDAR, 2022) AISHWARYA C. H.,; S.R.SOMASHEKAR
    The present study is based on the observations of total 476 samples of Portunus sanguinolentus that were collected fortnightly from Mangaluru fish landing centre during March 2021 to December 2021. Out of 476 samples 237 were males and 239 females. Size ranged from 78.9 to 165.2 mm (carapace width). The analysis of co-variance test was employed to test the significance of regression of weight on carapace width; this indicated that there was no significant difference between the sexes of P. sanguinolentus. Pooled carapace length - weight relationship is expressed as W= 0.8397L2.7888 and for carapace width weight W= 0.0451L3.0894. The condition factor Kn for both the sexes showed more or less similar values, males (1.0155) were higher than females (1.01005). This indicates identical metabolic activity in both the sexes. The data on percentage occurrence of food items indicates that P. sanguinolentus is bottom feeder, that feed predominantly on crustaceans, mollusc, fishes and large quantities of sand, debris and unidentified matters. GSI values of males ranged from 0.7223 to 1.060 and in females it ranged from 1.9582 to 3.56693 with maximum in August. The ovigerous females were found throughout the study period with peak in March, April and May. This suggest that P. sanguinolentus breeds throughout the year along Mangaluru coast. Size at first maturity revealed that females (116 mm CW) attain sexual maturity earlier than males (118 mm CW). The fecundity ranged from 1, 67, 499 eggs to 9, 23, 560 eggs. With an average fecundity of 4, 59,082 eggs. The estimation of proximate composition revealed that moisture (84.22%) formed major part followed by protein (11.97%), fat (1.78%) and ash (1.41%). This species has high protein content and it is beneficial for human consumption