Population parameters of the fish fauna in a long-established Amazonian reservoir (Amapá, Brazil)

Abstract

The present study focused on the fish fauna of the 44-yearold Coaracy Nunes reservoir in the northern Amazon basin, producing estimates of the growth constant (k), maximum and asymptotic body lengths and weights, natural mortality (M), the consumption/biomass ratio (QB) (intake of food by a group over a year), the Aspect ratio (Ar) of the caudal fin, growth performance (Φ), longevity, and trophic level for 45 fish species. Species collection was divided into eight sampling campaigns between May 2009 and July 2010. Gillnets were used in four of the sampling sites. The results revealed that (i) the most predominant species are Ageneiosus ucayalensis, Hemiodus unimaculatus, Serrasalmus gibbus and Geophagus proximus; (ii) small and medium-sized fishes predominated in the community, characterized by high rates of growth and natural mortality, consistent with a predominance of r-strategists; (iii) the body lengths of the detritivore species were similar to those of the piscivores, which are normally larger, but with higher growth rates, more similar to those recorded for the omnivores; (iv) consumption/biomass ratio (QB) 9 body length relationship is higher in the detritivores than in the omnivores and piscivores (which were similar to each other). Overall, the reservoir habitat appears to be advantageous to detritivorous fish species.

Upstream and downstream responses of fish assemblages to an eastern Amazonian hydroelectric dam

“…Species classification into five trophic guilds was based on stomach contents analysis, as described in Sá‐Oliveira, Angelini & Isaac‐Nahum (). Further details of body measurements are presented in Sá‐Oliveira, Angelini & Isaac‐Nahum ().…”

Length–weight relationships of eight fish species from Guyana coastal drainages, Amapá, Brazil

“…These data can be useful for fisheries research and stock management, and also fill in gaps about the understanding of the local ichthyofauna. However, despite the recent increase of published LWR studied for Amazonian fishes (e.g., Freitas et al, ; Cella‐Ribeiro, Hauser, Nogueira, Doria, & Torrente‐Vilara, ; Giarrizzo et al, ), including studies in the same aquatic biogeographic region (Nobile et al, ; Sá‐Oliveira, Angelini, & Isaac‐Nahum, ), there is still much work to be done considering that the Amazon basin comprises the most diverse freshwater fish fauna in the world (Reis et al, ). It is especially true for low commercial interest species (Freire, Rocha, & Souza, ), such as those reported herein.…”

First study on infestation of Excorallana berbicensis (Isopoda: Corallanidae) on six fishes in a reservoir in Brazilian Amazon during dry and rainy seasons

“…For study of parasites, specimens of Acestrorhynchus falcirostris (Acestrorhynchidae), Ageneiosus ucayalensis (Auchenipteridae), Geophagus proximus (Cichlidae), Hemiodus unimaculatus (Hemiodontidae), Serrasalmus gibbus (Serrasalmidae) and Psectrogaster falcata (Curimatidae) were collected in the Coaracy Nunes Reservoir (Fig. 1), a long-established ecosystem, about 40 years (Sá-Oliveira et al, 2015). A total of 296 fish specimens were caught during the dry season (October 2012 to February 2013) and rainy season (April to August 2013) at six sampling points, located at a distance of 889 ± 498 m (range: 544-1777 m) from each other (Fig.…”