Alterations in Size, Weight and Morphology of the Eggs of Blue Swimmer Crab, Portunus pelagicus Linnaeus, 1758 (Decapoda, Brachyura, Portunidae) during Incubation

Abstract

Portunus pelagicus Linnaeus, 1758 is an important candidate species for culture in India and trials are for developing its hatchery technology. The present work investigates the changes occurring in diameter, volume, wet weight and morphology of P. pelagicus eggs during incubation which would improve the knowledge base on embryology of species. Mated females from wild were maintained under similar physico-chemical conditions. Once spawned, the egg samples were collected from each animal daily and their diameter, volume, and wet weight were assessed. Based on the changes occurring in egg morphology at 24 hour intervals, the embryo development was classified into eight ‘periods’. The egg size and wet weight varied significantly (P<0.01) among crabs and egg size was unrelated with the carapace width of female. The average diameter, volume and wet weight of the egg were 0.324 mm, 0.016 mm3 and 0.048 mg, respectively. Diameter, volume and wet weight of the eggs increased to 13.58, 46.52 and 49.05%, respectively and the major share of increment occurred in last two days.