Ovarian development in the freshwater prawn Macrobrachium asperulum (Decapoda: Palaemonidae)

Abstract

Macrobrachium asperulum is a native freshwater prawn species in Taiwan, and is an ideal model for studying the reproductive biology of freshwater decapods. Also, this species may be a potential aquaculture species. This study was conducted to explore the ovarian development of female M. asperulum, as an important foundation for the knowledge of its reproductive biology. Specimens were collected in four seasons throughout the year to investigate the ovarian cycle and germ cell development, by examining the external morphology and histological structure of the ovaries. The breeding period of M. asperulum is probably from March to September each year. Developing ovaries and germ cells were characterized throughout the entire ovarian cycle. Differentiating germ cells were classified mainly into ogonia, primary ocytes, secondary ocytes, and mature ocytes. Among the four major germ cells, secondary ocytes were further divided into five types. Summarizing the above examinations and based on the relative frequency of germ cell types, six stages of ovarian cycle were identified, and this prawn is proposed as being a multiple spawning species. Observations of the present study provide important information on the reproductive biology of crustaceans and decapods in general, and also can serve as a significant foundation for the aquaculture of freshwater prawn species. © 2010 The Crustacean Society.