The reproductive biology and culture of macrobrachium vollenhovenii (Herklots, 1857) and macrobrachium macrobrachion (Herklots, 1851) in Nigeria.

Abstract

Macrobrachium vollenhovenii and Macrobrachion, the two largest Macrobrachium species in Nigeria waters attain maximum adult sizes of 19cm and 13.5cm respectively. Male - female ration is approximately 1.1 for both species. Male dimorphism has been observed in M. macrobrachion but not in M. vollenhovenii. Both prawns breed throughout the year (usually in the brackish waters) with peaks in the rainy season. Although berried females of M. vollenhovenii occur in landlocked water bodies, rearing the larvae has so far been successful in brackish water. Bi-weekly spawning peaks occur in M. macrobrachion but are still to be verified for M. vollenhovenii. Induced spawning has been successful carried out for M. vollenhovenii by using a combination of pituitary hormone and changes in illumination, temperature and water level. Clutch size ranges from 1,000 - 10,000 for M. macrobrachion and 45,00 - 400,000 for M. vollenhovenii. Egg incubation takes 16-20 days in both species. Two culture trials using diets of 14% crude protein and agriculture by-products of unspecified composition, gave growth rates of 0.24g/day and 0.03g/day respectively.