Girella nigricans





The Girella nigrican is an omnivorous, common fish that feeds primarily on red and green algae (3).  The niche of the opaleye fish includes temperate, shallow waters along the coast from San Francisco Bay to the southern tip of Baja California, Mexico, and north of La Paz into the Sea of Cortez (1, 2).  Since the main ecosystem of this species remains the kelp forest, the fish beholds significant ecological importance (1). More specifically, the opaleye fish is a constant grazer that contributes to algae balance in kelp forests by impeding algal takeover (1).  From this, potential for competition with other sessile invertebrates and algae species is made possible thus an increase within biodiversity (1).


(1) Bredvik, J.J., Boerger, C., Allen, L.G. (2011). Age and Growth of Two Herbivorous, Kelp Forest Fishes, the Opaleye ( Girella nigricans) and Halfmoon (Medialuna californiensis).  Bulletin, Southern California Academy of Sciences, 110(1), 25-34.  https://doi.org/10.3160/0038-3872-110.1.25

(2) Terry, A., Bucciarelli, G., Bernardi, G. (2001). RESTRICTED GENE FLOW AND INCIPIENT SPECIATION IN DISJUNCT PACIFIC OCEAN AND SEA OF CORTEZ POPULATIONS OF A REEF FISH SPECIES, GIRELLA NIGRICANS.  Evolution, 54(2), 652-659.  https://doi.org/10.1111/j.0014-3820.2000.tb00066.x

(3)  Behrens, M.D., Lafferty, K.D. (2012). Geographic Variation in the Diet of Opaleye (Girella nigricans) with Respect to Temperature and Habitat. PLoS ONE, 7(9), e45901.  https://doi.org/10.1371/journal.pone.0045901

(Photographs)  Peter J. Bryant, University of California, Irvine


  • Kelp Forest