Marine Management News Fish Identification Quiz
May 2012

May 2012 MMN Fish Quiz Photo; Photo by M. DuVernay

This flatfish moves from its shallow water feeding grounds to deeper waters along the continental shelf to spawn between November and March. This migration may happen only every other year in a behavior biologists call "skip spawning." Recently, electronic tags on this species recorded a previously unknown behavior, when fish swam towards the surface then drifted back down to the bottom. Biologists believe this may be similar to "spawning rises" seen in other flatfish, when female and male fish swim vertically in the water column to release and fertilize eggs closer to the currents that disperse them.

As they develop, the eggs slowly rise towards the surface, drifting with the currents for about two weeks before hatching. After hatching, the young fish swim upright with one eye located on each side of the body. The left eye begins to rotate over the snout to the right side of the body when the fish reaches about one inch in length. By the time both eyes have settled on the right side of the body and the left side pigmentation has faded to white, the young fish are about one and one-third inches long and looking for a home in shallow, nearshore waters, generally between May and September.

Very young fish feed on plankton. As they develop, they shift to feeding primarily on fishes, clam, crab, squid and other invertebrates. As adults, this fish is sometimes eaten by marine mammals, but is rarely preyed upon by other fish.

As they grow, young fish move offshore to deeper, sandy habitat. Females become mature at eight to 16 years of age (average 12), however males mature earlier. A large female of 140 pounds may produce over 2 1/2 million eggs.

This fish ranges from Santa Barbara, California to Nome, Alaska off North America, at depths from 20 to 3,600 feet. Off California, most are found in nearshore areas from Fort Bragg northward.

The fisheries for this species are strictly regulated with gear restrictions, open/closed seasons, area restrictions, and bag limits. The catch in California is dwarfed by much larger catches of this species in northern waters. Commercial landings in California are now negligable, with only a few hundred pounds brought ashore in 2010. Significantly more fish were landed prior to the 1950s, but after 1952 landings rapidly decreased and never recovered. In 2011, recreational fishermen in southern Oregon and northern California landed an estimated 9,648 lb. of this species.

This fish is a Pacific halibut, Hippoglossus stenolepis. The daily bag and possession limit for Pacific halibut is 1 fish, per CCR Title 14, Section 28.20(b).