In an article in the Canadian Journal of Fisheries and Aquatic Sciences, the authors say the population of barred sand bass and kelp bass began to shrink in the early 1980s amid regional changes in ocean conditions, including warmer temperatures.
But since then, a combination of environmental factors and fishing in seasonal spawning areas appears to have “pushed the species over the edge,” said the study’s lead author, Brad Erisman, a postdoctoral researcher with the Scripps Institution of Oceanography at the University of California, San Diego.
Yet the decline of barred sand and kelp bass stock went undetected because large numbers of fish continued to gather in the spawning areas favored by recreational fishermen, creating what the researchers call an “illusion of plenty,” the report said.
Dr. Erisman’s team found that the total regional stock of the two bass species had declined by at least 90 percent since 1980. Under criteria recognized by authorities including the United Nations Food and Agriculture Organization, that constitutes a collapse.
http://green.blogs.nytimes.com/2011/10/24/2-fisheries-collapsed-unnoticed-study-says/