Feeding and social behavior of the piabanha, Brycon devillei (Castelnau, 1855) (Characidae: Bryconinae) in the wild, with a note on following behavior

Abstract

Knowledge concerning the behavior of wild freshwater fishes in Brazil is restricted to a few studies, despite such studies being able to answer fundamental questions about conservation. Species of Brycon are amongst the most threatened in the Neotropics, particularly in southeast Brazil, due to anthropogenic activities in this region. This study investigated the feeding and social behaviors of the endangered fish, Brycon devillei in the Preto River, Jequitinhonha basin, Minas Gerais State, Brazil. Behavioral data were collected by snorkeling with four spatially separated groups (habituated), and direct observations of shoals were made using an underwater video camera (a total of 448 hours of observations). This species showed diverse tactics to obtain food. However, the species proved to be predominately a specialist surface-picker, which adopted alternative tactics to find food at certain times of the year, most notably when food items on the water surface became low. Feeding frequency was shown to be negatively correlated to agonistic behavior between conspecifics. Feeding associations were also recorded between the anostomid Leporinus garmani, acting as a nuclear species, and B. devillei, as follower species. The data presented here showed the importance of conserving the riparian environment to protect B. devillei populations. Furthermore, the present study included rare observations of nuclear-follower feeding association among freshwater fishes, especially between medium-sized characiforms, being the first observations of such kind in a Cerrado stream.O conhecimento do comportamento de vida livre em peixes de água doce brasileiros é restrito a poucos estudos e pode responder a questões fundamentais de conservação. Espécies do gênero Brycon estão entre as mais ameaçadas na região neotropical, especialmente no sudeste brasileiro, em vista de diversos impactos antrópicos. O presente estudo investigou os comportamentos alimentar e social de Brycon devillei no rio Preto, bacia do Jequitinhonha, Brasil. Para tanto, utilizou-se seções de mergulhos livres para observação direta de quatro grupos habituados de B. devillei, com o auxílio de câmeras filmadoras subaquáticas. Tal espécie apresentou variadas táticas para obtenção de alimento. Entretanto, a espécie demonstrou ser um forrageador de superfície especializado que, em determinados períodos do ano, quando provavelmente a lâmina d'água torna-se uma fonte escassa de recursos, adota táticas alternativas em busca de alimentos. A frequência de forrageamento demonstrou ser negativamente correlacionada com os comportamentos agonísticos. Foram observadas associações alimentares interespecíficas envolvendo o timburé, Leporinus garmani, como espécie nuclear, e a piabanha, Brycon devillei, como sua seguidora. Os dados apresentados no presente estudo demonstram a importância de se conservar o ambiente ripário em prol da proteção das populações de B. devillei. Além disso, o presente estudo é um dos raros registros de associação alimentar do tipo nuclear-seguidor entre peixe...

Influence of a large dam and importance of an undammed tributary on the reproductive ecology of the threatened fish matrinxã Brycon orthotaenia Günther, 1864 (Characiformes: Bryconidae) in southeastern Brazil

“…Its body weight may reach more than 7 kg, thus it is a very important fish for commercial and sport fishing (Gonçalves et al, 2006). In riparian forests in the Neotropics, fruits and seeds is an essential part of the diet of adult Brycon species; and thus these fish play an important role in the dispersal of plants (Azevedo et al, 2011). This migratory species is threatened in rio São Francisco, and it is included in the Red List of the International Union for Conservation of Nature (IUCN), in the category of vulnerable due to an inferred population reduction of greater than 30% over the last ten years due to overfishing and destruction of riparian vegetation (Reis & Lima, 2009).…”

Diversidad de la ictiofauna de la laguna Hule, Costa Rica

“…Desbalance en la cadena trófica que puede poner en riesgo la supervivencia de varias especies y comprometer la estabilidad del ecosistema Impartir talleres en la zona advirtiendo los riesgos que implica introducir especies en el lago Pesca no controlada y utilización de artes de pesca destructivos Disminución de las poblaciones de las especies afectadas Colocar rótulos donde explícitamente se indique la ilegalidad de la actividad y las medidas legales (multas u otras); crear un grupo comunal que vigile la zona varias veces a la semana Young, 2011;Kasumyan & Marusov, 2015). A. aeneus además es muy importante en la red trófica, dado su papel en el ecosistema como uno de los principales recicladores de nutrientes (nitrógeno y fósforo), en hábitats donde hay poco aporte de los mismos (Small et al, 2011).…”

Juvenile silver grunter Mesopristes argenteus shift benthic objects to access food

“…There are also a number of fishes (and other fauna) in both marine and freshwater systems that are known to disrupt the benthos during feeding and are followed by fish that stand to gain from prey being flushed from hiding (Baker & Foster, ; Sazima et al, ; Teresa et al, ). In the past decade, there has been a steady increase in scientific interest in this form of behavioural interaction within freshwater ecosystems and notably in a tropical South American context (Azevedo et al, ; Costa‐Pereira, ; Garrone Neto & Carvalho, ; Sabino et al, ; Teresa et al, , ). This literature primarily addresses how disrupting soft benthos has the capacity to alter stream fish assemblages by exposing benthic prey for both nuclear and follower fishes, with ramifications for fish assemblage composition specifically as a function of conditions favouring particular nuclear and follower species (Baker & Foster, ; Sabino et al, ; Teresa et al, , ).…”