GENETIC IMPLICATIONS OF RESTOCKING PROGRAMS ON WILD POPULATIONS OF STREAKED PROCHILOD <i>Prochilodus lineatus<i>

Abstract

Genetic diversity of wild and farmed populations is crucial, both for conservation of fish resources and fish culture development. To infer the genetic diversity and population structure of Streaked prochilod Prochilodus lineatus, individuals were sampled between 2007-2009 from four fish farms and from the Upper Uruguay River Basin, both in southern Brazil. Population structure was identified in both farmed and wild individuals through seven microsatellite loci. Bayesian analysis indicated three main groups, including two from fish farms. Pairwise genetic differentiation showed spatial structure between and within wild and farmed populations; however, the sampling design did not allow testing temporal structure according to isolation-by-time (IBT), which means that populations can breed within the same geographic distribaution, but reproduce at different times. Cultivated individuals presented lower diversity, allelic richness and effective population size, but higher inbreeding rates, compared to wild populations. These characteristics constitute warning signs against indiscriminate restocking of natural Prochilodus lineatus populations, a species sensitive to fragmented habitats, with farmed fish.

Reproductive performance of lambari ( Astyanax altiparanae ) in a seminatural system using different protocols

“…Its production increased 136.07% in Brazil from 2016 (237 tons) to 2017 (554 tons) (IBGE, 2018) and the species is currently produced in 23,028 fish farms (Peixe BR, 2020). Lambari is a low‐trophic level fish with a large potential to be produced in a sustainable way, such as in integrated multi‐trophic systems (Fonseca et al., 2017), and it is also one of the main species used for restocking fish programs in South American rivers, where they are reintroduced in areas with reservoirs to mitigate the environmental impact of hydroelectric dams (Iwersen et al, 2019). Its captive production serves dozens of fish programs across the American continent via the production of millions of larvae every year (Iwersen et al, 2019).…”