Otolith elemental composition reveals separate spawning areas of anchoveta, <em>Engraulis ringens</em>, off central Chile and northern Patagonia

Abstract

The anchoveta (Engraulis ringens) is widely distributed throughout the Humboldt Current (4°30′-44°S). In recent years, its eggs and larvae have also been found inside fjords and channels of northern Patagonia, close to the southern limit of the central-south Chilean fishery zone. Currently, it is unclear whether these southern individuals constitute an independent subpopulation. This study analysed the elemental composition of otoliths from 102 specimens from central Chile and northern Patagonia using laser ablation inductively coupled plasma mass spectrometry. The results indicated that the elemental composition of the otolith cores (Mg, Pb, Zn, Ba) differed significantly between sites, revealing the existence of two discrete spawning zones, one in central Chile and one in northern Patagonia. However, the low significant differences of elemental signatures of otolith edges suggest that either individuals from both areas move between spawning areas and mix at certain periods of the year, or they represent pocket units that form part of a larger stock that moves along the coast.

Variation in otolith microchemistry for Lebranche mullet (Mugil liza) in southern Brazil and its potential use in identifying their nursery grounds

“…In fact, the average concentrations of metals in estuarine water in Patos Lagoon correspond to the natural base levels described for other estuarine systems, but sporadic increases in Cu and Pb concentrations have been related to the ingress of industrial effluents and activities in the limnic area of Patos Lagoon (Seeliger et al, 1997). Although findings from some other research indicate associations of the highest Pb concentrations in otoliths with port areas (Cuevas et al, 2019), the effects of the time during which fish are exposed to Pb and of physiological processes should be considered (Vrdoljak, 2020). The nurseries sampled at both TRA and PLE are in highly populated areas.…”

“…This temporal variability can confuse spatial differences, meaning differences in elemental composition of otoliths among fish from different nurseries. Therefore, it is important to consider interannual differences in otolith microchemistry (Gillanders, 2002;Cuveliers et al, 2010;Reis-Santos et al, 2012), and assignment of origin (to specific nurseries or sampling sites) should be done only for year-classes for which an otolith chemical signature has been identified for juveniles. For this reason, it would be ideal if sampling and monitoring programs systematically collect otoliths over a period of several years, compiling a library of reference elemental markers than can be later used to determine the nursery origin of coastal adult fish (Gillanders, 2002;Reis-Santos et al, 2013).…”

Natal Contributions of Kokanee Salmon to Flaming Gorge Reservoir, Wyoming–Utah: An Evaluation Using Otolith Microchemistry

“…Linear regression was conducted to evaluate the relationship between the 87 Sr/ 86 Sr of water samples and ratios derived from the edge of otoliths (Bath et al 2000;Kennedy et al 2000;Barnett-Johnson et al 2008;Muhlfeld et al 2012;Heckel et al 2020). Kruskal-Wallis and post-hoc pairwise comparisons tests (Wilcoxon ranked-sum tests; α = 0.05) were conducted to compare the 87 Sr/ 86 Sr from the otolith edge among hatcheries and FGR (Young 2011;Cuevas et al 2019).…”

Temperature and prey density drive growth and otolith formation of the world's most valuable fish stock

“…The analysis of otolith microstructure (i.e., the number and width of daily increments) is a widely used technique in fisheries science to provide estimates of age and back-calculated somatic growth rate 19 , 20 . The technique has been widely applied to obtain the information needed for the stock assessment and management of the Peruvian anchovy stock in the HCS 21 , 22 . An underlying assumption is the daily formation of otolith micro-increments 23 which should be validated to ensure that otoliths provide a robust estimate of fish age.…”