Effects of stocking density on dispersal behavior of Brazilian freshwater dourado (Salminus brasiliensis) in a subtropical river headwater

Abstract

Juvenile freshwater dourados (Salminus brasiliensis Cuvier) were stocked in two batches of different size (61 and 133 individuals) with a time lag of 41 days in the headwaters of the Sinos River. A subsample of 25 fish was radio-tagged. Released juveniles displayed a density dependent dispersal pattern. During the first ten days mean covered distance of tagged batch 1 individuals (low density) was approximately 24 m d . O nível alto de movimentos na situação de maior densidade é visto como resultado da competição intraespecífica. As médias das distâncias percorridas por dia permanecem altas até os indivíduos introduzidos estabelecerem-se nos seus habitats novos.

Fish movement in an Atlantic Forest stream

“…Long distance movements (regional) are related mainly to reproduction, colonization of available habitats (Adams, Warren, 2005) as well as genetic exchange between populations (Henriques et al, 2010). In order to increase the offspring survival and to avoid intraspecific competition, some species displace kilometres and occupy specific habitats, with higher productivity and lower predator density (Schulz, Leal, 2012). Long spawning migration can occur in some fish groups, such as salmonids and large migratory fishes from Amazon and Paraná basins (Goulding, 1980;Winemiller, Jepsen, 1998;Antonio et al, 2007;Fernadez et al, 2007;Pesoa, Schulz, 2010;Tejerina-Garro, Mérona, 2010).…”

Upstream and downstream migration speed of Prochilodus costatus (Characiformes: Prochilodontidae) in upper São Francisco basin, Brazil

“…The Neotropical fish fauna is the most diverse on earth with over 5000 freshwater species described to date (Reis et al, 2016), some of which exhibit migratory behavior to some degree. Neotropical freshwater fish species that undertake long-distance migrations between spawning and feeding areas are mostly potamodromous and iteroparous (Godinho et al, 2010), but there are many knowledge gaps with respect to specific aspects of their migration dynamics (Schulz, Leal, 2012). For example, there is a dearth of knowledge on the upstream and downstream migration speeds of the vast majority of tropical fish species (Lucas et al, 2001) and few studies have measured the speeds attained by Neotropical species during spawning and post-spawning migrations.…”