The antarctic oscillation index as an environmental parameter for predicting catches of the argentine shortfin squid (Illex argentinus) (cephalopoda: Ommastrephidae) in southwest Atlantic waters

Abstract

With data from Taiwanese jiggers that targeted the Argentine shortfin squid (Illex argentinus) in the southwest Atlantic between 1986 and 2010, we used log-transformed catch per unit of effort (logU) as an index of the abundance of this squid to explore squid recruitment strength in response to environmental conditions. The logU was negatively correlated with subsurface seawater temperature (at a depth of 5 m) observed during February and April on the southern Patagonian shelf during the fishing season. The logU was also correlated with the Antarctic Oscillation (AAO), positively correlated in December of the fishing season and in March and May of the previous 2 years, and negatively correlated in November and December of the previous 2 years. A generalized linear model selected 4 environmental variables as predictors of annual catches that accounted for 83% catch variation: AAOs in November and March of the previous 2 years and subsurface seawater temperatures in March of the current and previous year in the southern location. The AAO would not directly affect the squid abundance more than 1 year later and biotic and abiotic linkages between atmospheric circulation patterns and stock fluctuations are not understood.