Untitled

Abstract

Studies were conducted on the growth and mortality parameters, recruitment pattern, probability of capture, yield-per recruit, and present rate of exploitation of the African river prawn, Macrobrachium vollenhovenii from Dawhenya impoundment, Ghana. Estimation of the von Bertalanffy growth parameters gave; L ∞ = 14.2 cm, K = 1.0 yr-1 , and t o =-0.195 yr-1 with the growth performance index, Ф' of 2.303. From the linearised length-converted catch curve, total mortality, Z was 5.36 yr-1. Natural mortality, M calculated from Pauly's empirical formula was 2.20 yr-1 and fishing mortality, F calculated from Z-M was 3.16 yr-1. From the mortality estimations, the present rate of exploitation, E calculated from F/Z was 0.59 indicating that, the species is on the verge of being over-exploited in the impoundment. Using the estimated value of the growth coefficient, K, the longevity was found to be about 3 yrs. Estimations from the probability of capture routines gave the length-at-first capture, L c as 3.07 cm while the size distribution of the catches suggest two recruitment pulses in a year. It is therefore recommended that, the property right-based system for fisheries management should be implemented so that fishermen can cooperate in the management of the Macrobrachium fishery.

Geographical variation of the structure and population parameters of the freshwater prawnMacrobrachium macrobrachion(Herklots, 1851) in West African coastal hydrosystems: Insights from Benin

“…This variation in growth performance in the two populations of M. macrobrachion could be justified by the differential growth in size within individuals of the same age as well as by the modifications of the physical and chemical parameters of the water of each site (Zinsou et al, 2016), which can influence the growth of individuals (Gabche & Hockey, 1995). The values of Ф′ obtained in the present study are lower than the values estimated for other stocks of palaemonid prawn species, in particular, species of the genus Macrobrachium such as M. vollenhoveni (Ф′ = 2.303) (Alhassan & Armah, 2011). The estimated Ф′ values in this study indicate that M. macrobrachion from the two study environments could be classified in the group of species with low growth.…”

“…The different values of the mortality parameters estimated in the present study are much lower than those reported by Enin (1995) in the same species in Nigeria and by Alhassan and Armah (2011) for M. vollenhoveni in Ghana. This difference in mortality could be linked to the phenomenon of emigration because this phenomenon sometimes appears as apparent mortality, although it can be compensated by the phenomenon of immigration (Laevastu & Favourite, 1988).…”

“…(2013) on M. macrobrachion in the Niger River Delta in Nigeria. These differences in growth could be due to the ecological conditions of the habitats and the size of the sample (Alhassan & Armah, 2011; Rodríguez‐Félix et al., 2015).…”

“…Sure, there is fragmented information on the demographic parameters of some species of the genus Macrobrachium in some West African aquatic environments (Abowei & Deekae, 2010; Alhassan & Armah, 2011). However, in the context of environmental and climate changes, environmental variables greatly influence the biological parameters of the population in fish or crustaceans (Koussovi et al., 2019; Montchowui et al., 2009).…”

A test of large-scale reproductive migration in females of the amphidromous shrimp Macrobrachium acanthurus (Caridea : Palaemonidae) from south-eastern Brazil

“…Also, males attain a smaller body size than females: 12 and 32 mm CL, two and 12 months after larval settlement, respectively. Previous studies have reported rapid growth rates in other species of Macrobrachium (Kanaujia et al 1997;Romero and Silva 2008;Alhassan and Armah 2011) (see review in Table 4 (1970) who reported an initial body size of 6.5 mm total body length (TL) and 27 mm TL for juveniles 40 days and two months after metamorphosis, respectively (data obtained from laboratoryreared specimens after larval development). Using previously published equations that relate CL to TL (CL ¼ 0.533 Â TL and CL ¼ 0.5043 Â TL in males and females, respectively: Albertoni et al 2002), our results fit well with those previously reported by Choudhury (1970) for males but not for females.…”