Spatial and interannual variability in the distribution of euphausiid life stages in the permanent upwelling system off northern Chile

Diaz-Astudillo, Macarena; Saldias, Gonzalo S.; Letelier, Jaime; Riquelme-Bugueno, Ramiro

Abstract

Euphausiids are crustaceans with a complex life cycle that play a significant role in the trophic pathways of the highly productive Humboldt Upwelling System. We studied the effect of upwelling and climate variability on the austral spring distribution and abundance of krill life stages using 8 years of physical and biological sampling off northern Chile. During the study period, conditions shifted from negative to positive temperature anomalies and climate indices. Consequently, large interannual variability associated with the El Nino Southern Oscillation and the Pacific Decadal Oscillation was observed in all life stages, with lower abundances during their positive phases. The distribution patterns and the statistical associations with environmental variables show that the effect of upwelling varies ontogenetically. Eggs, nauplii, calyptopis, and furcilia larvae had higher abundances offshore, suggesting they are transported offshore through the Ekman layer. Juveniles and adults avoid advection via their deeper distribution and vertical migrations, and although they were present in the entire study area, abundances were higher to the south associated with lower salinity. This is the first study evaluating the impacts of climate variability on krill life stages and finds a direct effect of these low-frequency oscillations on krill reproduction and abundance in the HUS.

Más información

Título según WOS: Spatial and interannual variability in the distribution of euphausiid life stages in the permanent upwelling system off northern Chile
Título de la Revista: ICES JOURNAL OF MARINE SCIENCE
Volumen: 79
Número: 1
Editorial: OXFORD UNIV PRESS
Fecha de publicación: 2022
Página de inicio: 61
Página final: 75
DOI:

10.1093/icesjms/fsab241

Notas: ISI