Exploring long-term variability of Nephrops norvegicus landing per unit effort (LPUE) off North Galicia (NW Spain)

Abstract

articleLandings of Nephrops norvegicus from North Galicia (Northwest Spain) have decreased by 80% from 1975 to 2001. Variability in the landings per unit effort (LPUE) of this stock was investigated by using time series approach. The LPUE time series (1975–2001) exhibited a seasonal pattern. The seasonal decomposition of the LPUE showed a declining in the trend-cycle component from 1987 onwards. Univariate and dynamic regression ARMA models were fitted to the LPUE time series. Population (proportion of males, proportion of ovigerous females and recruits) and environmental variables (temperature, salinity, nitrates and chlorophyll at 70 m depth, upwelling and sea surface temperature) were tested at different lags as explanatory variables. The proportion of males 4 years ago was the key factor explaining LPUE fluctuations.1,586