Trophic ecology of commercial-size meagre, Argyrosomus regius, in the Bay of Biscay (NE Atlantic)★

Abstract

-In the north-eastern Atlantic, meagre (Argyrosomus regius) is one of the largest fish living on the shelf and this species has important commercial interest. Over the past two decades, large variations in meagre abundance have been observed with pluri-annual cycles but the factors involved in such variations are still unclear. Trophic interactions between meagre and other species (both prey and competitors) might be one explanatory variable of the observed variations in meagre recruitment and abundance. In the present study, we described the diet of commercial-size meagre in the Bay of Biscay from stomach content and stable isotope analyses, and explored its dietary ontogeny. We found that commercial-size meagres were mostly piscivorous with a diet dominated by clupeiform fish (mainly anchovy and sardine) completed by demersal fish (mainly pout and whiting). Cannibalism also accounted for a non-negligible part of the diet. Interestingly, stable isotope and stomach content analyses showed only a very slight increase in prey length and trophic level during the ontogeny of large meagre after 50 cm of total length and despite a 3 fold-change of the individual length in our sampling. Our results suggested that specific trophic interactions (i.e. bottomup control by clupeiform fish on meagre population, competitive effects on piscivorous populations or topdown control by meagre on clupeiform fish populations) may occur in the Bay of Biscay and can impact meagre abundance dynamics. Our study underlined the interest to enhance ecological knowledge of preypredator relationships in the development of ecosystem-based approach to understand trophic controls impacting aquatic living resources and fishery economy.

Importance of Sample Gear in the Identification of Trophic Guilds and Forage Species in a Large Lagoonal Estuary

“…; Hubans et al. ) Sciaenids support important commercial and recreational fisheries on the U.S. East Coast and in other areas of the world (Haimovici ; Silva et al. ; Ihde et al.…”

“…Sciaenids are important prey for numerous predators in several estuarine and coastal environments throughout the world (Binion-Rock 2018). In addition to being important in the diets of predators in Pamlico Sound and Chesapeake Bay (Hartman and Brandt 1995;Overton et al 2009;Buchheister and Latour 2011;Ihde et al 2015), sciaenids are important prey in other estuarine and coastal environments in the USA (Wenner et al 1990;Bowman et al 2000;Patrick and Moser 2001;Luczkovich et al 2002;Sagarese et al 2011;Wuenschel et al 2013;Smylie et al 2015) and globally (Konchina 1983;Smale and Bruton 1985;Cazorla 1996;Lucena et al 2000;Krumme et al 2005;Hubans et al 2017) Sciaenids support important commercial and recreational fisheries on the U.S. East Coast and in other areas of the world (Haimovici 1998;Silva et al 2002;Ihde et al 2015;NCDMF 2016). If the goal of identifying forage species is to prevent ecosystem overfishing (Pikitch et al 2004), then predatory impacts on sciaenids should be more thoroughly evaluated.…”

Using acoustic telemetry to estimate post-release survival of undulate ray Raja undulata (Rajidae) in northeast Altantic

“…Based on their large sizes and geographical distributions, seals (Halichoerus gripus and Phoca vitulina), bottlenose dolphin (Tursiops truncatus), tope (Galeorhinus galeus), and meagre (Argyrosomus regius) were identified as the only potential predators of large skates in the Bay of Biscay. However, examination of stomach contents revealed no consumption of skates and rays by this group of species (Hauksson and Bogason, 1997;Hubans et al, 2017;Mikkelsen et al, 2002;Morato et al, 2003;Pierce et al, 1991;Santos et al, 2001). This suggests that only scavengers would have eaten dead rays, leaving tags undamaged.…”

Risk and benefit assessment of seafood consumption harvested from the Pertuis Charentais region of France

“…In addition, young meagre display a trophic regime based on crustaceans, i.e. poor Hg prey (Hubans et al, 2017) before switching towards a piscivorous diet (i.e. Hg enriched fish prey), limiting again the Hg intake in these individuals.…”