Effects of salinity gradients on larval growth and otolith asymmetry of austral hake Merluccius australis

MAURICIO F. LANDAETA, GISSELLA CASTILLO-HIDALGO, CLAUDIA A. BUSTOS

Submited: 2016-11-04 12:41:02 | Published: 2018-03-17 18:18:33

DOI: https://doi.org/10.3856/vol46-issue1-fulltext-20

Abstract


Austral hake Merluccius australis sustain an important demersal fishery in South Pacific and Atlantic Oceans. The main spawning and nursery areas are in the Chilean Patagonia, which is characterized by large inputs of freshwater from rivers and ice melting. We studied the spatial distribution of larval austral hake M. australis during spring, and the potential effects of oceanographic conditions (temperature, salinity, vertical stability and turbidity) on early life traits, derived from sagitta otolith microstructure analysis, size-at-age (SAR), individual larval growth (IGR) and bilateral asymmetry (FA6). Larval abundance ranged between 0.86 and 41.55 ind. 1000 m-3 (median: 4.08 ind. 1000 m-3) and population larval growth estimated by microincrement counts of sagitta otoliths was 0.129 ± 0.010 mm day-1, with age varying from 4 to 24 days old. All three indicators derived from otolith analysis (SAR, IGR and FA6) showed positive and significant correlations with vertical salinity gradients; IGR and FA6 were also positively correlated to Brunt-Väisälä frequency (vertical stability) and FA6 was correlated to turbidity. Therefore, larval M. australis were larger-at-age, grew faster and showed more asymmetry in areas with more influence of freshwater runoff in south Pacific Patagonia.

LANDAETA M, CASTILLO-HIDALGO G, BUSTOS C. Effects of salinity gradients on larval growth and otolith asymmetry of austral hake Merluccius australis. Lat. Am. J. Aquat. Res.. 2018;46(1). Available from: doi:10.3856/vol46-issue1-fulltext-20 [Accessed 20 Jan. 2019].
LANDAETA, M., CASTILLO-HIDALGO, G., & BUSTOS, C. (2018). Effects of salinity gradients on larval growth and otolith asymmetry of austral hake Merluccius australis. Latin American Journal of Aquatic Research, 46(1). doi:http://dx.doi.org/10.3856/vol46-issue1-fulltext-20