Asociación entre la Corriente de Deriva de los Vientos del Oeste y la abundancia relativa del pez espada (Xiphias gladius) frente a la costa de Chile

Abstract

The relationship between the relative abundance of swordfish (Xiphias gladius) off the Chilean coast and the latitudinal location of the West Wind Drift (WWD) was analyzed from a macro scale standpoint for the period between 1989 and 1996. The position of the axis of the eastern boundary of the WWD was estimated by determining the latitude of the bifurcation of the isotherms obtained from the average monthly sea surface temperatures. The capture per unit effort (CPUE) of the small-scale driftnet fleet was used as a relative abundance index for the resource. The WWD and CPUE time series were analyzed on a monthly scale with different lags between the series. Two methodological approaches were used to determine the relationship between these two time series. The first was the methodology proposed by Pyper & Peterman (1998), which was used to correct the actual degrees of freedom in the cross-correlation test. The second approach consisted in analyzing the correlation of two stationary time series at different lags. Those approaches indicated a significant relationship between the latitudinal location of the WWD and the CPUE on a monthly scale. The relationship found between the WWD and the swordfish relative abundance suggests that the WWD could be a macro scale indicator of oceanographic and meteorological variability that could affect swordfish distribution patterns and availability.