E-Letter responses to:

review: Francisco P. Chavez, John Ryan, Salvador E. Lluch-Cota, and Miguel Ñiquen C. From Anchovies to Sardines and Back: Multidecadal Change in the Pacific Ocean Science 2003; 299: 217-221 [Abstract] [Full text] [PDF]

E-Letters: Submit a response to this article

Published E-Letter responses:

Sardine Cycle Longer than fifty years

Eric D. Gamble, John Issacs, Andrew Soutar, and Peter Crill   (29 January 2003)

Sardine Cycle Longer than fifty years 29 January 2003
Eric D. Gamble, retired Scripps, John Issacs, Andrew Soutar, and Peter Crill Respond to this E-Letter: Re: Sardine Cycle Longer than fifty years	Research by Issacs and Soutar of the Marine Life Research Group at Scripps Institution of Oceanography in the early 1970s demonstrated that the sardines cycle every 80 to 100 years. They were able to verify sediment cores dated back into the early 1700s by radio isotope research with Edward Goldberg and Kenneth Bruland of the Geological Research Division. Soutar observed three distinct rises and complete declines of the sardines; one in each of the last three centuries. The research also pointed to a temperture connection and an inverse correlation with the anchovy biomass, although the anchovy never completely disappeared from the California coast. The rises of the sardine populations occur in a relative short period of time and appear to be logarithmic, suggesting a breeding frenzy. The declines, on the other hand, occur slowly over a period of 20-plus years. This attrition rate was not significantly different in any of the cycles observed, indicating that the fishing pressure from the doomed cannery industry had no effect. Ironically, the 1940s decline was blamed on the fishing industry and used politically to foster "man's negative influence on the environment" propaganda.