Reproductive biology of the palaemonid prawn Macrobrachium villosimanus (Tiwari, 1949) (Decapoda: Caridea: Palaemonidae)

Abstract

Abstract Macrobrachium villosimanus (Tiwari, 1949) is a commercial prawn found in southern Asia. There is, however, no available information on the population parameters of this species, which is an obstacle in the formulation of its sustainable management and conservation protocols. We studied for the first time its reproductive biology including, size at sexual maturity, reproductive period, egg size and volume, and brood size. Monthly samples were collected from the Andharmanik River, southern Bangladesh during December 2018 to November 2020 and only female individuals were used. All females were categorized as ovigerous and non-ovigerous based on the presence of eggs attached to the pleopods, and the developing eggs were classified into four stages. Ovarian development was also observed and classified. The size at which 50% of females were ovigerous was estimated as 13.3 mm carapace length. Occurrence of ovigerous females throughout the year indicated a prolonged spawning season with two peaks in March (minor peak) and June-December (major peak). Ovarian maturation was observed during embryogenesis, implying that females were potentially capable of multiple spawning during a reproductive period. Egg size was independent of female size but increased with development. Brood size was closely related to female size with isometric function. The findings will help to formulate sustainable management and conservation protocols of this important fishery.