Joel Gallup, an environmental and political reporter for the Newport News-Times, has an interesting column on Tidepool.com about a potentially revolutionary mechanism for managing fish populations in the Northwest Pacific: monitor the gonads of female black rockfish, which increase and decrease in weight with the fluctuations of El Nino.
Blanchard and his friends measured the weight of female reproductive organs -- incongrously, called "gonads" in black rockfish -- the species that prompted Oregon's Labor Day sport closure. They correlated the female gonads' weight to sea surface temperatures. The gonad weights they found in the non-El Nino year of 1996 were the same they found in 1995, when there was a mild El Nino. The mild event had no effect on gonad weight, compared to the normal winds year of 1996.
But in 1997, when a full-fledged El Nino arrived, gonad weights dropped. It was a signal that went unrecognized, but it foretold of fewer groundfish being born that year -- and fewer catch fish in the near future.