International Journal of
Fisheries and Aquaculture

  • Abbreviation: Int. J. Fish. Aquac.
  • Language: English
  • ISSN: 2006-9839
  • DOI: 10.5897/IJFA
  • Start Year: 2010
  • Published Articles: 193

Full Length Research Paper

Mortality, recruitment pattern and exploitation rates of two Schilbe Oken, 1817 populations: Schilbe mandibularis and Schilbe intermedius from the Aghien Lagoon; estuarine system of West Africa

Sonan Romuald Assi
  • Sonan Romuald Assi
  • Department of Biodiversity and Sustainable Management of Ecosystems, Faculty of Environment, Jean Lorougnon Guédé University, POB 150 Daloa, Côte d’Ivoire.
  • Google Scholar
Koffi Félix Konan
  • Koffi Félix Konan
  • Department of Biodiversity and Sustainable Management of Ecosystems, Faculty of Environment, Jean Lorougnon Guédé University, POB 150 Daloa, Côte d’Ivoire.
  • Google Scholar
N'guessan Gustave Aliko
  • N'guessan Gustave Aliko
  • Department of Biodiversity and Sustainable Management of Ecosystems, Faculty of Environment, Jean Lorougnon Guédé University, POB 150 Daloa, Côte d’Ivoire.
  • Google Scholar
Koffi Charles Boussou
  • Koffi Charles Boussou
  • Department of Biodiversity and Sustainable Management of Ecosystems, Faculty of Environment, Jean Lorougnon Guédé University, POB 150 Daloa, Côte d’Ivoire.
  • Google Scholar
Kotchi Yves Bony
  • Kotchi Yves Bony
  • Department of Biodiversity and Sustainable Management of Ecosystems, Faculty of Environment, Jean Lorougnon Guédé University, POB 150 Daloa, Côte d’Ivoire.
  • Google Scholar
Aka Jean-Paul Agnissan
  • Aka Jean-Paul Agnissan
  • Department of Aquatic Biology, Faculty of Sciences and Environment Managment, Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire.
  • Google Scholar
Germain Gourène
  • Germain Gourène
  • Department of Aquatic Biology, Faculty of Sciences and Environment Managment, Nangui Abrogoua University, 02 BP 801 Abidjan 02, Côte d’Ivoire.
  • Google Scholar


  •  Received: 14 February 2018
  •  Accepted: 27 March 2018
  •  Published: 30 April 2018

Abstract

In Côte d’Ivoire, the Aghien Lagoon is under heavy fishing pressure. Mortality, recruitment pattern and exploitation rate of Schilbe mandibularis and Schilbe intermedius were investigated in this lagoon. Fish samples of both sexes (N = 575) were collected monthly between June 2014 and May 2015 from artisanal and experimental captures. Natural mortality was higher in S. intermedius (M = 0.89 years-1) than in S. mandibularis (M = 0.58 years-1). The population of S. intermedius was more vulnerable to fishing (F = 2.90 years-1) than S. mandibularis (F = 0.51 years-1). The Z/K ratio (Z/K = 2.65 for S. mandibularis; Z/K = 4.85 for S. intermedius) indicated that mortality was predominant over growth for the two species. The recruitment pattern showed one Gauss curve translates was continuous for each species. For S. mandibularis, the exploitation rate (E = 0.47) was close to E 0.1 (E 0.1 = 0.46), indicating that S. mandibularis’s stock was in an optimum state of exploitation. However, for S. intermedius, Emax was lower (Emax = 0.57) than the exploitation rate (E = 0.77). This result reflected overexploitation of this species.

Key words: Schilbe mandibularis, Schilbe intermedius, mortality, recruitment, exploitation, Aghien Lagoon.