California halibut are large, toothed flatfish found in nearshore waters and may be described as being an estuarine-inner shelf species. They are visual ambush predators that range from Magdalena Bay, Baja California north to the Quillayute River in Washington, being most abundant from central California to Baja California. Though they may be found in ocean waters as deep as 600 ft (183 m), they are most often caught by anglers in 10 to 90 ft (3 to 27 m) of water. California halibut are broadcast spawners, and eggs are fertilized externally. Adults migrate from the continental shelf into shallow coastal waters and bays before spawning, usually from February through September. Eggs are pelagic (free floating). Larvae develop with one eye on each side of the head. As California halibut mature and reach the post-larval stage (20-29 days), one eye migrates to the other side so that both eyes are on the same side. California halibut may be right- or left-eyed.
California halibut are usually uniformly brown to brownish-black on the eyed side, and have the ability to change skin color patterns to camouflage with the substrate. They may have white spots, especially juveniles, which often fade after death. The non-eyed side is usually entirely white, though some mottling may occur. The lateral line is most distinctive and is highly arched above the pectoral fin. The mouth is large with conical teeth. The maxilla (top jaw bone) extends beyond the eye. There are less than 77 soft dorsal rays.
Pacific halibut vs. California halibut
In the Pacific halibut (Hippoglossus stenolepis), the maxilla extends only to the front edge of the eye, whereas the maxilla extends beyond the eye in California halibut. Pacific halibut have more than 80 soft dorsal rays and the eyes are always on the right side of the head whereas California halibut will have less than 77 soft dorsal rays and the eyes may be on the right or left side (dextral or sinistral).