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Solar Activity and the Abundance of Sardine Catches
Reference
Guisande C., Ulla, A. and Thejll, P.  2004.  Solar activity governs abundance of Atlantic Iberian sardine Sardina pilchardusMarine Ecology Progress Series 269: 297-301.

What was done
The authors compared sunspot numbers and cycle lengths of the past century with concomitant annual landings of juvenile sardines at Vigo (northwest Spain).

What was learned
Guisande et al. report that annual sardine landings from 1906 to 2002 off the northwest coast of the Iberian Peninsula "vary according to solar activity."  More specifically, they report that "when the solar cycle is short, there is a trend towards increasing water transport onshore, which favors larval retention in areas close to the coast and, hence, sardine catches increase," while "when the solar cycle is longer, the trend is toward increasing water transport offshore, carrying eggs and larvae into areas where there is not enough food to survive and, therefore, decreasing sardine catches."

What it means
Noting that "sardine landings show synchronous variations over approximately 25 years off Japan, California, Peru and Chile (Kawasaki et al., 1991)," Guisande et al. say their findings suggest that "sunspot activity may be the ultimate driving force behind large-scale atmosphere-ocean variability and the regime shifts observed in marine ecological systems (Mann, 1993; Chavez et al., 2003)," which reveals, in their estimation, "the potential importance of solar activity on all biological processes affected by coastal upwelling, including pelagic fisheries."  In concluding, therefore, they state that "the effect of solar activity on coastal water transport indicates that long-term changes in many biological processes in coastal areas may be regulated by solar activity."

References
Chavez, F.P., Ryan, J., Lluch-Cota, S.E. and Niquen, M.  2003.  From anchovies to sardines and back: multidecadal change in the Pacific Ocean.  Science 299: 217-221.

Kawasaki, T., Tanaka, S., Toba, Y. and Tanaguchi, A.  1991.  Long-Term Variability of Pelagic Fish Populations and Their Environment.  Pergamon Press, Oxford, United Kingdom.

Mann, K.H.  1993.  Physical oceanography, food chains, and fish stocks: a review.  ICES Journal of Marine Science 50: 105-119.

Reviewed 8 February 2006