Assessing the Viability of Reintroduction of Locally Extinct Migratory Fish Brycon orbignyanus: Successful Growth, Dispersal and Maturation

Abstract

The reintroduction of threatened fish species in areas where wild populations have been depleted due to anthropogenic impacts is an increasingly popular conservation tool and mitigation policy. Despite the importance of fish reintroduction for conservation purposes, little is known about its efficiency. Here, we assessed the viability of reintroduction of the endangered migratory fish, Brycon orbignyanus, in an area of the Upper Uruguay River basin where the species has not been reported for more than 30 years. We released 4000 yearling juveniles in the Pelotas River in 2014 and maintained 400 juveniles in captivity as a control population. After three years, a total of 13 individuals was recaptured, of which, 10 were considered sexually mature with first maturation being recorded in animals larger than 42 cm in total body length. The age–length comparison with a control population growth curve showed that recaptured fish were slightly bigger than those in captivity. Furthermore, important ecological attributes as schooling behavior and dispersal capacity were recorded for all recaptured individuals. Combined, our results suggest that the re-establishment of a self-sustained population of locally extinct species B. orbignyanus in the Pelotas River may be successful if sustained over time and supported by conservation policies.

A theory of change to reverse the current Mexican freshwater fish extinction crisis

“…The two lines of action described above will lead to the development of individual species reintroduction projects, for which the original sites will have to be restored or, where appropriate, new suitable sites will be identified, something that has been developed for various conservation projects in other countries (Cochran-Biederman et al, 2015;Esquivel-Muelbert et al, 2018) and in Mexico (Contreras-MacBeath et al, 2016;Domínguez et al, 2018). So, the expected result will be to return to nature some extinct in the wild and regionally extinct species.…”

Chapter 29: Restoration priorities and benefits within landscapes and catchments and across the Amazon basin

“…Heightened sensitivity to climate change could be offset if existing gradients in dry season intensity and rainfall drive adaptation towards greater drought or heat sensitivity. Primary forests are changing their species composition in response to climate change (Esquivel-Muelbert et al 2018); the fast turnover and high dispersal capacity of pioneer species may facilitate these changes in secondary forests, especially when they are functionally connected to a large species pool of potential colonists. It is therefore possible that more drought-resilient secondary forests could emerge in the future.…”

Ontogeny of swimming performance of hatchery‐reared post‐larvae and juvenile fish: a case of two threatened Mediterranean species

“…Indeed, individual swimming performance directly affects the dispersal, predation efficiency and escape performance of an organism, thus establishing a close link between swimming ability and survival (Stobutzki & Bellwood, 1997; Wolter & Arlinghaus, 2003). In addition to survival, habitat colonization is a mechanism linked to swimming performance and must be considered when estimating the success of a restocking programme (Esquivel‐Muelbert et al ., 2018). Therefore, the swimming performance of targeted species is key and should not be ignored.…”