Climate Variability & Marine Fisheries

Many species of fish occupy limited areas of the world's oceans defined by narrow temperature ranges. During El Niño events, as tropical areas in the Pacific warm, some species move farther poleward along the west coast into new areas. It is not clear if these species are avoiding areas that have become too warm or are simply taking advantage of food resources in areas that were previously too cold for them. Tropical species caught in California and farther north only during warm water events include hammerhead sharks, bonefish, Mexican barracuda, cutlassfish, puffers, and porcupinefish. Catches increase for warm water species normally caught in the warm season in southern California including dolphinfish, yellowtail and California barracuda. California sheephead, bonito, and swordfish, typically found in Southern California, are caught in northern Califonia during warm events and Pacific mackerel, skipjack tuna, Pacific bonito, bluefin tuna, and white seabass are caught off Oregon and

SST Anomalies, 1997 Click on image to enlarge

Washington. These northward extensions are sometimes seasonal and generally last less than 3 years although a few species such as the California sheephead have maintained small populations north of their previous range from relocated adults and young produced in new areas during the El Niño. The conditions are usually not suitable for survival of larvae of these species following the El Niño as these areas of the ocean cool.

Yellowtail Landings and El Niño Click on image to enlarge

(For a NOAA/NMFS website on the effects of El Niño on fish distribution, go to: http://www.elnino.noaa.gov/enso4.html)

	TEXT REFERENCES:
	1) J. Radovich. 1961. Relationships of Some Marine Organisms of the Northeast Pacific to Water Temperatures. Fish Bulletin. 112: 62pp.
	2) R. Lea. 2000. Observations On Fishes Associated With The 1997-98 El Niño Off California. CalCOFI Report. 41:117-129.
	3) Murawski, S.A. 1993. Climate Change and Marine Fish Distributions - Forecasting from Historical Analogy. Transactions of the American Fisheries Society. 122: 647-658.

	RELATED PUBLICATION:
	J. Norton. 1999. Apparent Habitat Extensions of Dolphinfish (Coryphaena hippurus) In Response To Climate Transients
	in the California Current. Scientia Marina. 63:239-260.