Limited contribution of hatchery-produced individuals to the sustainment of wild marble trout (Salmo marmoratus Cuvier, 1829) in an Alpine basin.

Autor: Righi T; Water Research Institute - National Research Council (IRSA - CNR), Largo Tonolli, 50, 28922 Verbania Pallanza, VB, Italy., Fasola E; Water Research Institute - National Research Council (IRSA - CNR), Via del Mulino, 19, 20861 Brugherio, MB, Italy., Iaia M; Water Research Institute - National Research Council (IRSA - CNR), Largo Tonolli, 50, 28922 Verbania Pallanza, VB, Italy., Stefani F; Water Research Institute - National Research Council (IRSA - CNR), Via del Mulino, 19, 20861 Brugherio, MB, Italy. Electronic address: fabrizio.stefani@irsa.cnr.it., Volta P; Water Research Institute - National Research Council (IRSA - CNR), Largo Tonolli, 50, 28922 Verbania Pallanza, VB, Italy.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2023 Sep 20; Vol. 892, pp. 164555. Date of Electronic Publication: 2023 Jun 01.
DOI: 10.1016/j.scitotenv.2023.164555
Abstrakt: Fish stocking constitutes a common management practice in freshwaters all over the world, to enhance fisheries or to support threatened fish populations. Pervasive detrimental effects may affect the real effectiveness of stocking programs. However, studies assessing the real impacts and relative contribution of stocked trout in wild populations are surprisingly few. The marble trout, Salmo marmoratus (Cuvier 1829), is a critically endangered sub-endemic salmonid in Northern Italy, and an iconic species for recreational fishing and conservation, also representing an emblematic case of species negatively affected by restocking. For instance, marble trout inhabiting the Toce River, the second largest tributary of Lake Maggiore, has been stocked with different hatchery congener trout belonging to the Salmo trutta complex (putative marble trout, Atlantic trout Salmo trutta Linnaeus 1758 and putative Mediterranean trout Salmo ghigii Pomini 1941) over the last decades. Using mitochondrial (D-loop) and nuclear (12 microsatellites and LDH-C1*) markers, we characterised the genetic variability and gene flow among the wild and hatchery individuals of marble trout of this basin, to investigate the effectiveness of stocking activities on the native residual population. Despite extensive hybridization of marble trout with non-native brown trout stocks was shown, the presence of individuals belonging to pure native stock has been detected as well. However, concerns could be advanced regarding its future persistence, due to climatic and hydraulic instabilities or loss of environmental heterogeneity. Moreover, despite ongoing yearly massive stocking activities, a negligible contribution of reared putative marble trout in the wild sample has been documented, suggesting that natural recruitment represents the greatest source of this wild population sustainment. Important adaptive differences between wild and domestic trout are present, likely due to the deleterious long-term effects of the close breeding system of hatcheries. Finally, possible implications for stocking management improvement have been discussed.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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