SciELO - Scientific Electronic Library Online

 
vol.59 número4Prey selection by two benthic fish species in a Mato Grosso stream, Rio de Janeiro, BrazilReproducción de Joturus pichardi y Agonostomus monticola(Mugiliformes: Mugilidae) en ríos de la Sierra Nevada de Santa Marta, Colombia índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados

Revista

Articulo

Indicadores

Links relacionados

Compartir


Revista de Biología Tropical

versión On-line ISSN 0034-7744versión impresa ISSN 0034-7744

Resumen

IDUMAH OKOGWU, Okechukwu. Age, growth and mortality of Clarias gariepinus (Siluriformes: Clariidae) in the Mid-Cross River-Floodplain ecosystem, Nigeria. Rev. biol. trop [online]. 2011, vol.59, n.4, pp.1707-1716. ISSN 0034-7744.

Clarias gariepinus is a threatened highly prized species used for some elite ceremonies by the local communities. Artisanal fishers take advantage of this species annual breeding migration from the lower Cross River to the floodplain lakes in Mid-Cross River during the rainy season, and some migrant stocks are not able to spawn. Since there is a lack of information on this species population dynamics in the Mid-Cross area, this study aimed to evaluate the age, growth and mortality to support the development of effective management plans. For this, monthly overnight gill net catches (from 6 to 72mm mesh sizes) were developed between March 2005 and February 2007. Growth parameters were determined using the FiSAT II length-frequency distribution. A total of 1 421 fish were collected during the survey. The asymptotic growth (L∞) was 80.24cm, growth rate (K) was 0.49/year while the longevity was 6.12years. The annual instantaneous rate of total mortality (Z) was 2.54/year and the natural mortality (M) was 0.88. Fishing mortality (1.66/year) was higher than the biological reference points (Fopt=0.83 and Flimit=1.11) and the exploitation rate (0.66) was higher than the predicted value (Emax=0.64) indicating that C. gariepinus was over exploited in the Mid-Cross River-Floodplain ecosystem. Some recommended immediate management actions are to strengthen the ban of ichthyocide fishing, closure of the floodplain lakes for most of the year, restricted access to the migratory path of the fish during the flood period and vocational training to the fishers. In order to recover and maintain a sustainable harvest, I suggest that a multi-sector stakeholder group should be formed with governmental agents, community leaders, fishers, fisheries scientists and non-governmental organizations. These short and long term measures, if carefully applied, will facilitate recovery of the fishery. Rev. Biol. Trop. 59 (4): 1707-1716. Epub 2011 December 01.

Palabras clave : Clarias gariepinus; Cross River; age; floodplain; Nigeria; over exploitation.

        · resumen en Español     · texto en Inglés     · Inglés ( pdf )

 

Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons