African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6574

Full Length Research Paper

Growth patterns and Fulton’s condition factor of the silver catfish Chrysichthys nigrodigitatus (Actinopterygii: Siluriformes: Claroteidae) from a sand-dragged man-made lake of Benin

Alphonse Adite
  • Alphonse Adite
  • Laboratoire d’Ecologie et de Management des Ecosystèmes Aquatiques (LEMEA), Département de Zoologie, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, BP 526 Cotonou, Bénin.
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Houehanou Megnisse A. G. Gbaguidi
  • Houehanou Megnisse A. G. Gbaguidi
  • Laboratoire d’Ecologie et de Management des Ecosystèmes Aquatiques (LEMEA), Département de Zoologie, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, BP 526 Cotonou, Bénin.
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Moudachirou Ibikounle
  • Moudachirou Ibikounle
  • Laboratoire de Parasitologie et d’Ecologie Parasitaire, Département de Zoologie, Faculté des Sciences et Techniques, Université d’Abomey-Calavi, BP 526 Cotonou, Bénin.
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  •  Received: 12 April 2017
  •  Accepted: 01 June 2017
  •  Published: 06 July 2017

Abstract

Notwithstanding the nutritional, economic and fisheries importance of Chrysichthys nigrodigitatus, and its relatively high abundance and propagation in Lake Ahozon (South Benin), nothing is known about the well-being of the species in this water body. Thus, this study investigated length and weight frequency distributions, length-weight relationships and condition factors of C. nigrodigitatus. A total of 1020 individuals of C. nigrodigitatus were sampled with seines, cast nets, gill nets and hooks during a 15 month period, from August 2014 to October 2015. Total length (TL) and body weight (W) frequency curves showed a unimodal distribution. The longest TL and highest W recorded were 324 mm and 456.1 g, respectively. In Lake Ahozon, C. nigrodigitatus population exhibited a significant (P≤0.01) isometric growth pattern, indicated by the power function (W = 0.011TL2.99; r=0.96) and the log-transformed linear regression equation (LogW = 2.99 LogTL - 1.94; r=0.96). Growth models varied spatially, sexually, ontogenetically, and seasonally, while corresponding subpopulations showed allometric or isometric growth trends, with slopes b ranging between 2.47 and 3.21. The population showed conditions factors (K) ranging between 0.8 and 3.08 which significantly varied with habitats (F1,1018 = 7.613, P  = 0.006), seasons (F2,1017 = 29, P = 0.0001) and life stage categories (F2,1017 =5.583, P = 0.004). The active breeding that provided an important stock of offspring for recruitment, the isometric growth model and the relatively high condition factors indicated the perfect establishment of C. nigrodigitatus in the artificial lake of Ahozon. The sustainable exploitation of fisheries in this non-conventional medium-environment requires an integrated approach of lake management.

Key words: Claroteid, condition factor, establishment, fisheries, isometric growth, length-weight model, man-made lake.