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Phenotypic Convergence in Sea Bass (Dicentrarchus labrax) Escaping From Fish Farms: The Onset of Feralization?
Frontiers in Marine Science, Volume: 8
Swansea University Author: Carlos Garcia De Leaniz
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Copyright © 2021 Toledo-Guedes, Brito and Garcia de Leaniz. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY)
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DOI (Published version): 10.3389/fmars.2021.674635
Abstract
The impact of fish escaping from fish farms may depend on the extent to which escapees adapt to the natural environment, resemble wild conspecifics, and become feral. Yet, little is known about the process of feralization in marine fish. We examined phenotypic changes in body shape, body condition,...
Published in: | Frontiers in Marine Science |
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ISSN: | 2296-7745 |
Published: |
Frontiers Media SA
2021
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URI: | https://cronfa.swan.ac.uk/Record/cronfa61496 |
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Abstract: |
The impact of fish escaping from fish farms may depend on the extent to which escapees adapt to the natural environment, resemble wild conspecifics, and become feral. Yet, little is known about the process of feralization in marine fish. We examined phenotypic changes in body shape, body condition, and scale growth profiles of sea bass escaping from fish farms in the Canary Islands and quantified the extent to which escapees had diverged from farmed conspecifics. Most feral sea bass had sizes that overlapped with those of farmed fish, indicating that they had escaped throughout the production cycle. However, 29% of escapees were larger than the maximum size at harvesting, indicating growth in the wild. Analysis of scale growth profiles showed that some escapees had grown in the wild as fast as cultured fish, albeit at more variable growth rates. Feral sea bass tended to converge towards a similar body shape, having more streamlined bodies, lower body condition, and lower hepatosomatic indices (HSI) than fish in cages. Although our study cannot discriminate between phenotypic plasticity and differential mortality of escapees, we interpret phenotypic convergence as the likely result of a period of initial starvation, phenotypic plasticity, and selection against maladapted phenotypes. Our results warn against the risks of rearing sea bass in open-net cages and suggest that sea bass escapees could pose a threat to shallow coastal assemblages, particularly in areas where the species is not naturally found. |
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Keywords: |
feralization, domestication, morphometrics, sea bass, fish scales, growth profiles |
College: |
Faculty of Science and Engineering |
Funders: |
KT-G was funded by a doctoral fellowship from Canary Island
Government co-financed by the European Union (FEDER),
postdoctoral tenure program Juan de la Cierva Formación (FJCI-2014-20100) and Juan de la Cierva Incorporación
(IJCI-2017-34174). Funded by Project GLORiA “GLObal change
Resilience in Aquaculture,” supported by the Biodiversity
Foundation of the Spanish Ministry for the Ecological Transition
and Demographic Challenge, through the Pleamar Program
and co-financed by the European Maritime and Fisheries Fund
(EMFF). It is also part of the LIFE IP INTEMARES project
“Integrated, innovative and participatory management of the
Natura 2000 Network in the Spanish marine environment.” |