California scorpionfish (scorpionfish) are easily distinguished from most other California fishes. They are a relatively heavy-bodied species, with strong head and fin spines, ranging in color from red to brown, often with purple blotches and always covered with dark spots. Scorpionfish are a nocturnal species. The sharp spines on the dorsal, anal and pelvic fins are poisonous.
Distribution, Stock Structure and Migration
Scorpionfish are found from Santa Cruz, California south along the Pacific coast of Baja California and into the Gulf of California. Preferring warmer water, this species is common as far north as Santa Barbara. Scorpionfish live from tide pools to depths of about 620 ft. A transient species, scorpionfish tagging studies have shown individuals to travel as far as 350 km. Some of these movements are related to annual spawning migrations, which are sometimes extensive.
Age and Growth
California scorpionfish grow to 17 in. and some live to at least 21 yr. After 4 yr of age, females grow faster than males and reach a larger size.
Reproduction, Fecundity and Seasonality
Although a few scorpionfish mature at 6 in. (1 yr), over 50 percent are mature by 7 in. (2 yr) and all reproduce by 9 in. (4 yr). They have separate sexes and females generally outnumber males. Spawning occurs from April to September, peaking in June and July. Scorpionfish are oviparous, have external fertilization, and females produce eggs imbedded in the gelatinous walls of hollow, pear-shaped "egg-balloons". The egg masses float near the surface and the eggs hatch within 5 days. California scorpionfish make extensive spawning migrations in late spring and early summer, when most adults move to 12 to 360 foot depths, forming large spawning aggregations on or near the bottom. During spawning, these aggregations rise up off the bottom, sometimes approaching the surface. Spawning occurs in the same areas year after year.
Scorpionfish are a carnivorous, ambush predator. Small crabs are probably the most important food of the scorpionfish. They are primarily nocturnal and feed at night. Octopi prey on small individuals.
No information on competitors of adult or juvenile scorpionfish is available.
Very young scorpionfish live in shallow water, hidden away in habitats with dense algae and bottom-encrusting organisms. Juveniles and adults are most abundant on hard bottom (such as rocky reefs, sewer pipes and wrecks).
Status of Stocks
In 2005, the southern California scorpionfish stock was assessed and accepted for management purposes in California. This was the first assessment of the California scorpionfish stock in southern California waters.
Assessment results indicated that scorpionfish biomass declined before 1980 and has since increased (healthy state) mainly due to changes in recruitment.
Information on this page was originally presented in the Nearshore Fishery Management Plan (these profiles updated July, 2010).