Links between the recruitment success of northern European hake (Merluccius merluccius L.) and a regime shift on the NE Atlantic continental shelf
KAUST DepartmentRed Sea Research Center (RSRC)
Biological and Environmental Sciences and Engineering (BESE) Division
Marine Science Program
Plankton ecology Research Group
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AbstractThe distribution of northern European hake (Merluccius merluccius L.) extends from the Bay of Biscay up to Norwegian waters. However, despite its wide geographical distribution, there have been few studies on fluctuations in the European hake populations. Marine ecosystem shifts have been investigated worldwide and their influence on trophic levels has been studied, from top predator fish populations down to planktonic prey species, but there is little information on the effect of atmosphere-ocean shifts on European hake. This work analyses hake recruitment success (recruits per adult biomass) in relation to environmental changes over the period 1978-2006 in order to determine whether the regime shift identified in several abiotic and biotic variables in the North Sea also affected the Northeast Atlantic shelf oceanography. Hake recruitment success as well as parameters such as the sea surface temperature, wind patterns and copepod abundance changed significantly at the end of the 1980s, demonstrating an ecological regime shift in the Northeast Atlantic. Despite the low reproductive biomass recorded during the last decades, hake recruitment success has been higher since the change in 1989/90. The higher productivity may have sustained the population despite the intense fishing pressure; copepod abundance, warmer water temperatures and moderate eastward transport were found to be beneficial. In conclusion, in 1988/89 the Northeast Atlantic environment shifted to a favourable regime for northern hake production. This study supports the hypothesis that the hydro-climatic regime shift that affected the North Sea in the late 1980s may have influenced a wider region, such as the Northeast Atlantic. © 2013 John Wiley & Sons Ltd.
SponsorsThe authors would like to thank the National Centers for Environmental Prediction (NCEP), the Climate Prediction Center (CPC), the Earth System Research Laboratory (ESRL), the Physical Sciences Division (PSD), the Pacific Fisheries Environmental Laboratory (PFEL) and the National Geophysical Data Center (NGDC), all of which belong to NOAA, the Sahfos Institution, Plymouth Marine Laboratory and the University of West Anglia, for providing environmental data. Grateful thanks also to Jose Antonio Fernandes for his assistance with machine learning techniques. Thanks are also due to C. Stonehouse for revising the English of this manuscript. N. Goikoetxea was supported by a research grant ('Oceanografia y Recursos Marinos') from the Fundacion Centros Tecnologicos, Inaki Goenaga. This research was funded by the European FP7 Integrated Project MEECE. This paper is contribution No. 633 from AZTI-Tecnalia (Marine Research Unit).