Growth and mortality of larval anchoveta Engraulis ringens, in northern Chile during winter and their relationship with coastal hydrographic conditions

Larval growth, age, growth effect and instantaneous mortality were estimated inanchoveta, Engraulis ringens, collected biweekly during the austral winter of 2014 innearshore waters off Bay of Antofagasta (23°410W–70°300S), northern Chile.Through measuring standard length (SL) and sagitta microstructure analysis, it wasestimated that the growth rate of E. ringens larvae decreased from June(0.85 mm day1) to August (0.50 mm day1). However, the water temperature washomogeneous during the sampling dates (14.6, 15.2, 14.4, and 14.6°C), suggestingthat the decelerating larval growth was not linked to changes in sea temperature.Additionally, larvae with slow growth have larger otoliths compared with con-specifics with fast growth (growth effect). Larval mortality rates tended to decreaseuntil the middle of July (0.18 per day) but increased to 0.25 per day in early August,which coincided with lower food availability (i.e., chlorophyll-a, 2.7–5.6 mg m3) anda high occurrence of smaller larvae (1.58–11.5 mm). Partial least squares analysisindicates low covariance between the biological and oceanographic variables (PLS:11.71%), suggesting that other factors, such as parental effects, may explain theabrupt decrease in the larval growth rates.