Fluctuations of landings and environmental conditions in the north‐western Mediterranean Sea

Abstract

Most of the monthly catches and CPUE of 13 studied commercial species in the coastal waters of the north‐western Mediterranean were significantly positively correlated with run‐off of local rivers (Rhône and Muga) and the wind mixing index during the spawning season, with time lags of less than a year (transfer function analyses). Rhône and Ebre interannual fluctuations in run‐off were synchronous and were related to the North Atlantic Oscillation (NAO), river run‐offs being negatively correlated to high NAO episodes. The fluctuations of river discharges and the wind mixing index were cyclic but not related. The results showed that enhanced hydroclimatic conditions in the NW Mediterranean were favourable for the productivity of the fish and invertebrate stocks, and suggest the presence of linkage between recruitment of Mediterranean species and local (river discharges, wind conditions) and global (NAO) environmental conditions.

Variaciones espacio-temporales a pequeña escala en la dinámica poblacional y biología de la gamba blanca <i>Parapenaeus longirostris</i> (Crustacea: Decapoda) en el Mediterráneo occidental

“…The influence of environmental conditions (sediment, water masses and availability of prey), observed in our study in a short spatio-temporal range, should also be taken into account when long-term trends are analysed. The importance of large-scale factors on the population dynamics of deep-water crustaceans has already been suggested (Relini and Orsi Relini, 1987;Carbonell et al, 1999;Anderson, 2000;Lloret et al, 2001;wieland, 2004;Koeller et al, 2007;Maynou, 2008). In our study area two oceanographic scenarios, associated with macro and meso-scale climate regimes, could influence the population dynamics of European hake and red shrimp .…”

Recruitment dynamics of eight fishery species in the northwest Mediterranean Sea

“…Landings (Lloret et al, 2001). The long-term decreasing trend in landings of small Merluccius merluccius is probably due to overfishing (Recasens and Lleonart, 1999), while the longterm increase in landings of small Mullus barbatus and M. surmuletus could be due partly to long-term environmental changes (e.g.…”

Geographic, bathymetric and inter-annual variability in the distribution of <i>Liocarcinus depurator</i> (Brachyura: Portunidae) along the Mediterranean coast of the Iberian peninsula

“…This could correspond to the high levels observed at the start of our time series and be part of a large overall cycle. A significant effect of wind mixing and river discharges on catches/recruitment of L. depurator in the north-western Mediterranean was found by Lloret et al (2001), among other species. Lags of six to eight months were recorded between catch/CPUE (catch per unit effort) and wind mixing and river flow.…”

“…The only previous study on a temporal series of catches of L. depurator is restricted to that of Lloret et al (2001), who found an increase in catches and CPUE for the short time series (1990)(1991)(1992)(1993)(1994) available for L. depurator from two harbours in the south-west Gulf of Lions. This time series ended precisely with relatively high density levels when our time series started in 1994.…”