The influence of environmental factors and hydrodynamics on the sardine (Sardinapilchardus, Walbaum 1792) abundance in the southern Alboran Sea
2018
Jghab, A. | Vargas-Yáñez, M. (Manuel) | Reul, A. | García-Martínez, M.C. (María del Carmen) | Hidalgo, M. (Manuel) | Bernal, M. | Benomar, M | Benchoucha, S. | Lamtai, A.
The study of environmental variables and their influence on the small pelagic fish stocks in the AlboránSea (Western Mediterranean) is asymmetrical being scarce those studies focused on the southern coastif compared to the northern one. In the present work, sardine landings time series from the Moroccancoast of the Alborán Sea from 1981 to 2016 area analyzed together with environmental variables suchas Sea Surface Temperature (SST), Sea Surface Salinity (SSS), Surface Chlorophyll-a concentrations andthe velocity of the Atlantic Jet flowing into the Mediterranean Sea through the Strait of Gibraltar. Sardineannual catches have decreased from 1981 to 2016 at a rate of -258 t/yr. At the same time, SST and SSShave increased at rates of 0.03 ºC/yr and 0.004 ups/yr, very likely as a result of climate change. Linearmodels reflect a negative relationship between sardine landings and SST and SSS indicating that the longterm changes of the temperature and salinity in the Mediterranean could have a negative impact of thesardine abundance. On an inter-annual time scale, chlorophyll concentrations seem to be positively relatedto sardine abundances.There is also a clear decrease of the kinetic energy of the AJ inferred from the cross strait sea leveldifference (SLD). This variable has a great influence (positive correlation) with the sardine landings bothat the long term and at the inter annual time scale with higher sardine abundances associated to higherSLD. Linear models in the present work show their ability to reproduce around 60 % of the sardine landingsvariance.
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