Fishing Down the Galapagos Marine Food Web

The designation of the Galapagos Marine Reserve has not entirely buffered the waters from change. Tom Okey, a former student of Daniel Pauly, showed that the phenomenon of "fishing down the food web" is indeed occurring in the islands (though fishing at lower trophic levels has also yielded bad results, to be discussed in a later post). The sailfin grouper (Mycteroperca olfax), once the most valuable and exploited fish (see photo of seco-selado), once made up more than 40% of the catch but now makes up 20% of catch. The average size of sailfin grouper also declined and in 1996, it was listed on the IUCN Red List of Threatened Species. Mullet has now replaced sailfin grouper as the primary catch. An increase in the endemic green sea urchins as well as the urchin Encidaris thouarsii and anemone barrens also attests to heavy fishing and disturbance.
Endemic green sea urchins
Photo by R. Wollocombe

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