Clues from the recent past to assess recruitment of Mediterranean small pelagic fishes under sea warming scenarios
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Knowledge of the effect of environmental variables on the early life history of fishes is essential to assess the effect of future environmental changes on the recruitment of commercial species. We investigate the effect of sea warming on two small pelagic fishes (Engraulis encrasicolus and Sardinella aurita) in the NW Mediterranean Sea based on the analysis of ichthyoplankton data collected in two surveys of contrasting conditions: the exceptionally warm summer of 2003, which may be indicative of conditions under future climate change scenarios, and the summer of 2004, with temperatures within the climatic average for the period 2000-2012. We use fine-resolution environmental variables measured locally and Generalized Additive Models to assess the influence of environment on these two summer-spawning small pelagic fishes. We show that sea surface temperature is the main environmental factor explaining abundance, but other factors (food availability and water currents) have additional roles tuning the effect of temperature. In the hot summer of 2003 we observed a decline of local egg production of anchovy and an increase of larval advection from the colder Gulf of Lions compared to 2004. Round sardinella spawning was higher in 2003 than in 2004 and extended over a wider area, but larvae viability was compromised by the lower availability of trophic resources. We hypothesize that future changes in environmental forcing on these two co-occurring summer spawning species will determine differential larval survival, with cascading effects on the upper trophic levels which feed on these species, including negative impacts on their fisheries.
KeywordsLarval Abundance Generalize Cross Validation Ebro Delta Deep Chlorophyll Maximum Small Pelagic Fish
This work was partially supported by the EU Project VECTORS (FP7 OCEAN-2010, 266445) and by the Spanish project FISHJELLY (MAR-CTM2010-18874). Analyses and visualizations used in this paper were produced with the Giovanni online data system, developed and maintained by the NASA GES DISC. We acknowledge the comments of three anonymous reviewers that helped improve the final version of the manuscript.
- Ben-Tuvia A (1960) Synopsis of biological data on Sardinella aurita of the Mediterranean sea and other waters. FAO Fish Biol Synopsis 14:287–312Google Scholar
- Burnham KP, Anderson DR (2002) Model selection and multimodel inference. Springer, New YorkGoogle Scholar
- Castellón A et al (1990) The liguro-provençal-catalan current (NW Mediterranean) observed by doppler profiling in the Balearic sea. Sci Mar 54:269–276Google Scholar
- CIESM (2008) Climate Warming and Related Changes in Mediterranean Marine Biota. CIESM Workshop Monographs, 35. Monaco. 152 pp.Google Scholar
- R Development Core Team (2011). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL http://www.R-project.org/.
- Estrada M, Salat J (1989) Phytoplankton assemblages of deep and surface water layers in a Mediterranean frontal zone. Sci Mar 53:203–214Google Scholar
- Font J et al. (1988) Permanent features of the circulation in the Catalan sea. In: Minas HJ, Nival P (eds) Pelagic Mediterranean oceanography. Oceanol Acta 9: 51–57.Google Scholar
- Hastie TJ, Tibshirani RJ (1990) Generalized additive models. Chapman and Hall, New YorkGoogle Scholar
- Hidaka K (1940) Absolute evaluation of oceanic currents in dynamic calculations. Proc Imp Acad (Tokyo) 16:391–393Google Scholar
- Lleonart J, Maynou F (2003) Fish stock assessments in the Mediterranean: state of the art. Sci Mar 67(1):37–49Google Scholar
- Molinero JC et al (2008) Climate control on the long-term anomalous changes of zooplankton communities in the Northwestern Mediterranean. Glob Change Biol 14:11–26Google Scholar
- Salat J (1996) Review of hydrographic environmental factors that may influence anchovy habitats in northwestern Mediterranean. Sci Mar 60(2):21–32Google Scholar
- Smith P, Richardson S (1977) Standard techniques for pelagic fish egg and larva surveys, FAO Fish Tech Pap 175. Food and Agriculture Organization of the United Nations, RomeGoogle Scholar
- Stewart RH (2008) Introduction to Physical Oceanography. http://oceanworld.tamu.edu/resources/ocng_textbook/contents.html
- Wasserman L (2005) All of nonparametric statistics, chapter 2. Springer, New YorkGoogle Scholar
- Wood S (2006) Generalized additive models: an introduction with R. CRC/Taylor and Francis.Google Scholar