Early life trophodynamic influence on daily growth patterns of the Alboran Sea sardine (Sardina pilchardus) from two distinct nursery habitats (bays of málaga and almería) in the western Mediterranean Sea

Abstract

The Alborán Sea sardine (Sardina pilchardus) is the most abundant small pelagic fish in the Mediterranean Sea. Along the northern coast of the Alborán Sea, Málaga and Almería Bay are two important nursery grounds with contrasting oceanographic characteristics. Post-larval stages of S. pilchardus were collected during the late autumn and late winter along with the mesozooplankton community. We examined the influence of feeding behavior on larval growth using environmental variables, daily growth metrics, otolith biometry, stable isotope analysis and trophodynamics. Trophic positions were calculated using mesoozooplankton as potential prey for S. pilchardus. During both seasons, we observed faster growth in larger otoliths that also corresponded to higher trophic positions. Our results indicate that the isotopic signature of larvae is highly influenced by the mesozooplankton community structure. Moreover, the trophic variables showed a significant linear relationship with the estimated ages for all larvae indicating dietary changes throughout ontogenic development.

Keywords: Alboran sea; Daily growth increments; European sardine; Feeding strategy; Isotopic enrichment; Larvae; Marine ecology; Otolith microstructure analysis; Stable isotopes; Trophic position.