MEPS prepress abstract  -  DOI: https://doi.org/10.3354/meps12962

New in the neighborhood: trophic ecology of expanding round sardinella and northwestern Mediterranean sympatric species

Marta Albo-Puigserver*, Diego Borme, Marta Coll, Valentina Tirelli, Isabel Palomera, Joan Navarro

*Email: albo@icm.csic.es

ABSTRACT: Abstract: The recent northward expansion of the round sardinella (Sardinella aurita) in the Mediterranean Sea has been documented as a consequence of sea temperature rise. At the same time, declines in sardine and anchovy biomass have been observed in the NW Mediterranean Sea. Therefore, there is a need to assess if the expansion of round sardinella may affect sardine and anchovy populations. Here, we combine stomach content and isotopic analyses to describe the trophic habits of round sardinella in the NW Mediterranean Sea and their trophic relationships with two sympatric small pelagic fish, the anchovy (Engraulis encrasicolus) and the sardine (Sardina pilchardus). Results revealed changes in the diet of round sardinella during the year. In summer, the most important preys were copepods (Acartia spp.) and cladocerans (Penilia avirostris). During winter, the diet was composed mainly of copepods and tunicates (mainly appendicularians), but microplankton was also numerically important in adult diets. In contrast to previous studies, during spring, round sardinella principally fed on salps (Thaliacea). To our knowledge, this is the first time that salps have been identified as an important prey for round sardinella. When compared to coexisting small pelagic fish, we found that round sardinella adults had a different trophic niche than anchovy and sardine. In contrast, round sardinella juveniles partially overlapped the trophic niche with the juveniles of the other two species. Our results provide new insights into the ecological role of this expanding species in the NW Mediterranean Sea and highlight the importance of gelatinous zooplankton as prey.