Influential environmental gradients and patterns of fish assemblages in a West African basin

Abstract

Twenty-two sites were monitored in the Lower Sassandra River Basin (Côte d'Ivoire, West Africa) to examine patterns in fish species assemblage structure along environmental gradients. Hierarchical clustering of the species presence-absence data identified four types of assemblages corresponding to the man-made Lake Buyo, the main channel, and the two major tributaries. Canonical Correspondence Analysis (CCA) indicated that canopy closure, leaves-wood, aquatic plants, temperature, width, total dissolved solids and depth were the environmental factors most strongly correlated with variation in the fish assemblages. Five species: Papyrocranus afer, Micralestes elongatus, Parailia pellucida, Tilapia busumana and T. mariae were reported from the basin for the first time. The investigation of the variation in species richness led to the assessment of a major anthropogenic disturbance induced by a palm oil factory. In conjunction with the fact that the Sassandra River hosts an endemic species, Synodontis koensis, it was concluded that this basin is of high conservation priority.

Distribution patterns of fish communities with respect to environmental gradients in Korean streams

“…Moreover, a rise in habitat diversity, as reflected in substrate composition (Goldstein and Meador, 2005;Needbling and Quist, 2010) and aquatic plant variety (Diddle et al, 1997), means that more fish species may be supported. Thus, the common observation that increasing habitat complexity changes the longitudinal distribution of fish species (Maturakis et al, 1987;Kouame´et al, 2008;Eitzmann and Paukert, 2010) is true of Korean streams.…”

Fishery yields vary with land cover on the Amazon River floodplain

“…changing species composition; Smokorowski & Pratt, 2007). In line with these expectations, studies of riparian deforestation of streams have found varied effects on fish biomass but consistent changes in assemblage structure (Bojsen, 2005;Bojsen & Barriga, 2002;Dias, Magnusson, & Zuanon, 2010;Giam et al, 2015;Iwata, Nakano, & Inoue, 2003;Jones, Helfman, Harper, & Bolstad, 1999;Kouamé, Yao, Bi, Kouamélan, & N'Douba, 2008;Lorion & Kennedy, 2009;Sweeney et al, 2004;Teresa & Casatti, 2012;Wright & Flecker, 2004). Loss of stream canopy cover generally increases light intensity and decreases inputs of allochthonous materials, increasing the portion of the fish community that is supported by autochthonous food sources such as phytoplankton (Allan, 2004;Angermeier & Karr, 1983).…”

Development of a fish-based index of biotic integrity (FIBI) to assess the quality of Bandama River in Côte d’Ivoire

“…), the use of fertilizers and pesticides in large plantations near running waters, the construction of hydro-agricultural and agro-pastoral dams (Go, Bandama, San Pedro, etc. ) and hydroelectric dams (Bia, Bandama, Sassandra) have perturbed normal assessment of ecosystems (Gourène et al, 1999;Da Costa et al, 2000;Koné et al, 2003;Kouamélan et al, 2003;Kouamé et al, 2008). Moreover, the introduction of species to improve small-scale fisheries, develop fish farming or for biological control (Gooré Bi, 2009) can affect the biological functioning of ecosystems through food chains.…”