Assessment of the African river prawn Macrobrachium vollenhovenii (Herklots, 1857) in some lentic and lotic environments in Nigeria

• Published in: African journal of ecology 1997-03, Vol.35 (1), p.80-81
• Main Authors: Bello-Olusoji, O A, Somers, MJ
• Format: Article
• Language: English
• Subjects: Freshwater; Macrobrachium vollenhovenii
• ISSN: 0141-6707
• DOI: 10.1111/j.1365-2028.1997.046-89046.x

Macrobrachium vollenhovenii is a tropical crustacean endemic to the eastern Atlantic. Its fishery has been reported in Senegal, Liberia, French Guinea, Ivory Coast, Gabon and Congo (Zaire) (Holthius, 1980). The present decline in the marine shrimp production as reported by Adetayo (1982) gives room for alternative ways of increasing shrimp production to reduce the overfished marine species. Macrobrachium vollenhovenii, a close relative of the giant fresh-water prawn (Macrobrachium rosenbergii), has commercial potential (Ajuzie & Fagade, 1992), which has not been fully developed in the manner of M. rosenbergii that is now being cultured commercially in SE Asia and in developed countries including the U.S.A. Its production in Indonesia is being described as the second most productive industry in the world with an increase in yield from 26,166 tonnes in 1983 to 120,000 tonnes in 1990 (Chamberlain, 1991). A twelve month survey was carried out, on 42 freshwater bodies, consisting of rivers, streams, ponds and reservoirs (lakes). They were grouped into two forms, lentic or standing (ponds and reservoirs) water and lotic or running water (rivers and streams). Macrobrachium species were found in 25 with M. vollenhovenii showing the highest occurrence in eighteen (72%) fresh water bodies made up of seven rivers (39%), four constructed fish ponds (22%), three reservoirs (17%) and four streams (22%). The prawns were caught using traps and nets set by fishermen on the relevant rivers and streams. In ponds, they were collected after draining the pond or caught alongside fin-fishes during harvesting. On each trip M. vollenhovenii was randomly sampled from the total catch. In the Laboratory samples were grouped into those from lotic environments and those from lentic environments. Twenty samples were picked randomly from each environment as shown in Table 1. These were separated according to their sizes, 13 females and 7 males. The weight (g), body length (cm) and pincer length (cm) were measured. The maximum total length and weight recorded was 16.0 cm (135 g) and 14.0 cm (125 g) for the lotic and lentic groups. Holithus (1980) reported maximum length of 18.2 cm for M. vollenhovenii.