Early life history traits of common sardine, Strangomera bentincki (Osteichthyes: Clupeidae) estimated by otolith microstructure analysis

Abstract

Common sardine, Strangomera bentincki, support an important artisanal fishery along the Chilean coast; however, there is lack of knowledge of the early life history traits of this species. Using satellite-derived environmental conditions (sea surface temperature, SST, and chlorophyll-a), and otolith microstructure analysis of larval stages collected in coastal waters of central Chile, larval age, growth rates, and back-calculated yolk-sac absorption date patterns were analyzed for 2010–2013. SST varied from 11 to 20 °C and showed the highest values during austral summer 2013, whereas Chl-a varied between 0.2 and 66 mg m−3. The abundance of larval S. bentincki was similar during 2010 and 2011, decreased in 2012 but increased again in 2013 to similar densities of 2010 to 2011. Similarly, larvae collected during 2012 had the largest otoliths (radius, perimeter, area). Larval growth rates did not vary significantly among years and ranged between 0.32 and 0.42 mm day−1. From 2010 to 2011, a significant decrease occurred in the size-at-age of larval S. bentincki, and then, size-at-age was maintained until 2013. Back-calculated yolk-sac absorption dates differed among years and were delayed from winter to spring during 2012. The latter occurred in a period with significantly warmer waters. Additionally, SST and Chl-a concentration were not linearly related to the mean growth rates of larval S. bentincki.