Multi-element otolith fingerprints unravel sea−lagoon lifetime migrations of gilthead sea bream Sparus aurata

Abstract

Precise knowledge of lifetime migrations is vital in exploited fish species, since all essential habitats must be protected to maintain sustainable stock levels. The present study used multi-element otolith fingerprints of the gilthead sea bream Sparus aurata (L.) to discriminate its main juvenile and adult habitats in the Languedoc-Roussillon region (Gulf of Lions, northwest Mediterranean) and infer the lifetime migrations of 12 individuals from the area (11 from the present day and 1 from the Roman era). This allowed for the first time the identification of key habitats for the successful completion of the species' life cycle in the Gulf of Lions, and the connectivity between them. Our results revealed that lagoon use by S. aurata is probably ancient (> 2500 yr) and confirmed its current commonness. Yet, although most observed migration patterns were in accordance with the migratory behavior previously described for the species, strong inter-individual variations and new patterns in habitat use were detected. At the juvenile stage, a preference for shallow lagoons with low salinities was evidenced. Nevertheless, the first year of life can also be successfully completed in marine conditions. At the adult stage, lagoon use was shown to occur until at least age 4 yr, with periods of lagoon residency of up to 11 mo in a year, often including winter months. Because overwintering in the lagoons was previously thought to be impossible for S. aurata due to low temperatures, this finding has important implications for future stock management, especially since the species breeds in winter. KEY WORDS: Otolith microchemistry · Trace elements · Random forest · Key habitats · Gulf of LionsResale or republication not permitted without written consent of the publisher

Response of Gilthead Seabream (Sparus aurata L., 1758) Larvae to Nursery Odor Cues as Described by a New Set of Behavioral Indexes

“…The facultative behavior of S. aurata in using coastal lagoons as nursery habitats for larvae, as observed in the Mediterranean Sea (Mercier et al, 2012;Tournois et al, 2013), confirms previous observations made in the Ria Formosa lagoon. The larvae of Sparidae were among the most abundant in this lagoon, and most of these larvae were post-flexion larvae collected during flood tides (Chícharo and Teodósio, 1991).…”

“…aurata may ingress into coastal lagoons as larvae (as early as pre-metamorphic larvae) or as juveniles during spring (Mercier et al, 2012;Tournois et al, 2013), returning to the coast during autumn (Mercier et al, 2012). Adults might reingress into coastal lagoons several times during their life even if they spent the juvenile phase at sea (Mercier et al, 2012).…”

“…While in coastal lagoons, adults use seagrass habitats more frequently than any other type of habitat, but without exhibiting a consistent diel pattern of activity (Abecasis and Erzini, 2008). Yet, adults may exhibit a homing behavior when displaced from their home range within the lagoon (Abecasis and Erzini, 2008), but without necessarily returning to their nursery lagoon later in life (Mercier et al, 2012). S. aurata exhibits high trophic plasticity (i.e., incorporate organic matter with different originsterrestrial, lagoon, marine) (Escalas et al, 2015) and feeding plasticity (Gamito et al, 2003;Tancioni et al, 2003).…”

Candidate gene variation in gilthead sea bream reveals complex spatiotemporal selection patterns between marine and lagoon habitats

“…After hatching at sea from De cember to February, a large proportion of the juveniles colonise coastal lagoons in March and April for foraging (Mercier et al 2011, Isnard et al 2015 before returning to the open sea in October and November to overwinter, when lagoon water temperatures drop (Audouin 1962, Lasserre 1974, Mercier et al 2012). In the Gulf of Lions, 2 lagoons, located about 30 km apart and offering very different nursery habitats, have been studied: (1) the Mauguio (MA) lagoon (also known as Etang de l'Or), which is shallow and highly productive, with warm summer temperatures and wide sali nity variations; and (2) the Thau (TH) lagoon, which is larger and deeper and ecologically more similar to the coastal marine environment due to major connections with the Mediterranean (e.g.…”

“…In the Gulf of Lions, 2 lagoons, located about 30 km apart and offering very different nursery habitats, have been studied: (1) the Mauguio (MA) lagoon (also known as Etang de l'Or), which is shallow and highly productive, with warm summer temperatures and wide sali nity variations; and (2) the Thau (TH) lagoon, which is larger and deeper and ecologically more similar to the coastal marine environment due to major connections with the Mediterranean (e.g. Mercier et al 2012, Tournois et al 2013 and references therein). Using candidate gene markers located in the proximal promoter of the growth hormone (GH) and prolactin (Prl) genes, Chaoui et al (2012) found non-neutral allele frequency shifts between young juveniles caught in marine and lagoon habitats and interpreted these patterns as a footprint of post-settlement selection.…”