Narrator: This is Science Today. For the first time, research indicates that fishing promotes the boom and bust fluctuations of fish stocks from highs to lows. Researcher George Sugihara of the Scripps Institution of Oceanography says the study was based on data obtained by the California Cooperative Oceanic Fisheries, or CalCOFI.
Sugihara: Normal fisheries data is based on landings – that means fish caught. The CalCOFI data sampled both exploited – or fish species – and unexploited. That's not found in fisheries data. Fisheries data don't have any records on fish that aren't caught – it's a catch-22.
Narrator: The question has long been, if there is an impact, is it due to fishing or some environmental effects?
Sugihara: What the CalCOFI allowed us to do is make a comparison of fish that were exploited and unexploited living in the same environment, so we could factor out the environment as the cause. When you analyze those data, the exploited fish stocks showed much more variability in their abundances than the unexploited ones.
Narrator: For Science Today, I'm Larissa Branin.