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

Abstract

Larval growth, age, growth effect and instantaneous mortality were estimated in anchoveta, Engraulis ringens, collected biweekly during the austral winter of 2014 in nearshore waters off Bay of Antofagasta (23°41′W–70°30′S), northern Chile. Through measuring standard length (SL) and sagitta microstructure analysis, it was estimated 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 was homogeneous during the sampling dates (14.6, 15.2, 14.4, and 14.6°C), suggesting that the decelerating larval growth was not linked to changes in sea temperature. Additionally, larvae with slow growth have larger otoliths compared with conspecifics with fast growth (growth effect). Larval mortality rates tended to decrease until 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) and a high occurrence of smaller larvae (1.58–11.5 mm). Partial least squares analysis indicates low covariance between the biological and oceanographic variables (PLS: 11.71%), suggesting that other factors, such as parental effects, may explain the abrupt decrease in the larval growth rates.

Revisiting daily age determination in juvenile anchoveta Engraulis ringens

“…Slower growth would produce a larger number of unresolved increments. The growth rate of the known-age anchovy larvae was very similar to that measured in wild fish (Contreras et al 2017), suggesting that the fitted curve is broadly appropriate in both reared and wild fish. However, growth rate variations across years are inevitable.…”

Effect of ENSO on the distribution and concentration of catches and reproductive activity of anchovy Engraulis ringens in northern Chile

“…However, in the long term, the increase in the intensity and duration of these specimens’ reproduction could account for a change in reproductive tactics that may increase recruitment success (Perea, Peña‐Tercero, Oliveros‐Ramos, Buitrón, & Mori, ), possibly due to an increase in temperature. Recent studies show that anchoveta grow fast (larvae between 0.50 and 0.85 mm/day (Contreras et al., )—juveniles between 0.65 and 1.02 mm/day (Cerna & Plaza, )). It is plausible that the higher temperature ENSO events caused may also accelerate sexual maturity of the juvenile fraction.…”

AnchovetaEngraulis ringensalong the Chilean coast: Management units, demographic units and water masses: Insights from multiple otolith‐based approaches

“…At the same time, we found greater latitudinal differences in otolith radius at day 40 ( R 40 ), which become 2.56 times larger at UM‐I than at UM‐III, in cohort 2015. Nonetheless, instantaneous growth rates ( g 10‐40 ) were similar between MUs and cohorts, suggesting otolith radius was rather affected by other processes, such as parental effects (Contreras et al, ), which may have a stronger control over hatching size than over the growth rate being considered here (10–40 days after hatching).…”