The diet ofCynopoecilus fulgensCosta, 2002 (Cyprinodontiformes: Rivulidae) in Southern Brazil wetlands

Abstract

Studies with annual fish diet have shown that the generalist habit is a dominant strategy within this group. Cynopoecilus fulgens (Cyprinodontiformes: Rivulidae) is a restricted range species, endemic to a small area in Southern Brazil, and aspects of its biology and ecology are poorly known. The main goal of the study was to determine the diet of C. fulgens throughout its life cycle and compare it with the prey availability in Southern Brazil wetlands. Specifically, we analyzed samples collected in different stages of ontogenetic development (immature and adult fishes) in various year seasons. A total of 52 food items were found in the diet of C. fulgens, and invertebrates comprised 96.4% of the counts observed. The richness of consumed and available prey changed along with the seasons. The seasonal variation of the consumed prey richness was mainly related to increase in fish size along the annual cycle. Microcrustaceans represented 75.6%, 80.9%, and 68.4% of the consumed prey in autumn, winter and spring, respectively. Prey composition varied with the seasons and it was not correlated to prey availability. Diet selectivity was different among male, female and immature fish. Our study reported the feeding habits of Cynopoecilus fulgens to improve knowledge of the biological and ecological traits of annual killifishes in Southern Brazil wetlands, where more than 90% of the original wetlands have been lost due to agricultural expansion.

Trophic strategy of Atlantirivulus riograndensis (Cyprinodontiformes: Rivulidae), a non-annual rivulid threatened by extinction, in a perennial environment, Brazil)

“…Dominance of autochthonous items in the diet revealed an expected standard for the feeding spectrum of A. riograndensis, corroborating the initial hypothesis that the species follows the pattern of other rivulids (Laufer et al, 2009;Goncalves et al, 2011;Keppeler et al, 2013).…”

“…Meanwhile, for Cynopoecilus fulgens there is a record of greater prey diversity in the summer and spring with more intense ingestion of Cladocera in summer and autumn (Keppeler et al, 2013), which is the same pattern identified in A. riograndensis, except for the consumption of microcrustaceans in summer as a main food item.…”

“…In the Rivulidae family ontogenetic influences were reported in the feeding of annual Austrolebias cheradophilus, C. melanotaenia and C. fulgens (Laufer et al, 2009;Keppeler et al, 2013).…”

“…Consumption of autochthonous insects and microcrustaceans as major components of the diet is reported in Brazil for: the non-annual rivulid Melanorivulus pictus (Cerrado biome) (Shibatta & Bennemann, 2003); the annual Simpsonichthys boitonei (in an ecological reserve of Cerrado) (Shibatta & Rocha, 2001); the annual Cynopoecilus fulgens (in an ecological reserve in the Pampa biome) (Keppeler et al, 2013); the annual Cynopoecilus melanotaenia (Pampa biome) (Gonçalves et al, 2011).…”

Seasonal variation in fish trophic networks in two clear-water streams in the Central Llanos region, Venezuela

“…Limited entry of allochthonous resources into the food web of streams in the Central Llanos region may be due, in part, to landscapes dominated by grasslands rather than forests. Forest density has been shown to be a good predictor for the importance of allochthonous items in fish diets in other Neotropical systems (Abilhoa et al, 2010;Keppeler et al, 2013). In addition to supporting terrestrial plant and animal biomass entering aquatic habitats, forests also block solar irradiance and, consequently, reduce autochthonous primary production, including phytoplankton and aquatic macrophytes (Goulding et al, 1988).…”