Adapting to the wild: the case of aquaculture‐produced and released meagres Argyrosomus regius. Issue 1 (5th November 2013)

• Record Type: Journal Article
• Authors: Gil, M. M.; Palmer, M.; Grau, A.; Deudero, S.; Alconchel, J. I.; Catalán, I. A.
• Is Part Of: Journal of fish biology. Volume 84:Issue 1(2014)
• Page Start: 10
• Page End: 30
• Publication Date: 2013-11-05
• Subjects: Fishes -- Periodicals; Fishes -- Great Britain -- Periodicals; 597
• DOI: 10.1111/jfb.12241
• Languages: English
• ISSNs: 0022-1112

Abstract

<abstract abstract-type="main" id="jfb12241-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p id="jfb12241-para-0001">The performance of juvenile <italic>Argyrosomus regius</italic> released off the coast of Mallorca Island (Balearic Islands, Spain) was assessed by comparing the body condition, stable isotope signature and stomach contents of aquaculture‐produced <italic>A. regius</italic> that had been released, fished and returned by fishermen after spending from a few days to >1 year at liberty with <italic>A. regius</italic> reared under controlled conditions on two contrasting diets (well‐fed and unfed). During the first 40 days of the experiment, the condition index (<italic>K</italic><sub>R</sub>) of the returned <italic>A. regius</italic> and the unfed <italic>A. regius</italic> followed the same decreasing trend. Thereafter, the <italic>K</italic><sub>R</sub> values of the returned <italic>A. regius</italic> were significantly higher than those of the unfed <italic>A. regius</italic> but never reached the values of well‐fed <italic>A. regius</italic>. The δ<sup>13</sup>C signal of the returned <italic>A. regius</italic> clearly increased (in comparison with the well‐fed <italic>A. regius</italic>) after they had spent a few months at liberty. The temporal pattern depicted by the stable isotopes and the most likely prey composition inferred from this pattern strongly suggest a shift in diet. The stomach contents of the returned <italic>A. regius</italic> that had spent <100 days at liberty consisted almost exclusively of decapods. The diet of the few returned <italic>A. regius</italic> that had spent >100 days at liberty consisted entirely of fishes. Wild <italic>A. regius</italic> from the remaining fishery on the Spanish coast exhibited the same ontogenetic diet shift from invertebrates to fishes, but at a smaller size threshold. Overall, the results demonstrated that culture‐reared <italic>A. regius</italic> experience adverse conditions during the first days after release into the wild but that at least some <italic>A. regius</italic> are able to adapt to the natural environment after a few months at liberty.</p> </abstract>