Eight Populations of Cabezon Discovered

August 23, 2007

Contact: Christina S. Johnson, csjohnson@ucsd.edu, 858-822-5334

Cabezon

Cabezon. Photo Margaret Webb

San Luis Obispo–New results of a California Sea Grant / California Department of Fish and Game study strongly suggest that West Coast cabezon are composed of multiple, genetically distinct populations. Eight different populations have been identified in California, Oregon and Washington.

Cal Poly San Luis Obispo biology professor Francis Villablanca, who led the genetic analysis, bases this conclusion on the distribution of genotypes in eight different regions along the West Coast. Certain genotypes were characteristic of different regions. See Figure 1 for a map of these regions.

“What we don’t know is why we see this pattern,” Villablanca said. “We don’t know if certain genotypes have been maintained because they confer some adaptive advantage or whether it is just genetic drift, in which genotypes are lost due to the relatively small size of the local breeding population.”

MAP

The number of fish analyzed for each of the different sampling sites. The color-coding shows the locations of the eight cabezon populations. Credit: Cal Poly San Luis Obispo.

An in-progress microsatellite analysis of nuclear DNA will help researchers determine which has occurred. The study reported here was based on an analysis of mitochondrial DNA samples taken from 244 cabezon along the West Coast.

Cabezon is a valuable component of the lucrative nearshore, live finfish fishery, in which fish are caught and sold live, often to Asian markets and restaurants.