Beringraja binoculata

Big Skate

Family: Rajidae · Class: Chondrichthyes · Order: Rajiformes

The big skate (Beringraja binoculata) is the largest skate species along the North American Pacific coast, reaching lengths up to 2.4 meters (8 feet) and weights exceeding 91 kilograms (200 pounds). This cartilaginous fish has a flattened, diamond-shaped body with a long, slender tail and distinctive large pectoral fins that extend like wings. The dorsal surface ranges from gray to brown with darker spots and blotches, while the ventral surface is white to cream-colored. Two prominent eyespots (ocelli) on the pectoral fins give this species its scientific name "binoculata," meaning "two-eyed." Big skates occur along the Pacific coast from the Bering Sea to Baja California, Mexico. In California waters, they are found from the intertidal zone to depths of approximately 800 meters (2,625 feet), though they are most commonly encountered between 10 and 360 feet according to the California Department of Fish and Wildlife. The species inhabits both northern and north-central California regions, with populations extending throughout the state's coastal waters. This species primarily occupies soft bottom habitats including sand, mud, and silt substrates. Adults occasionally venture onto rocky reefs but show a strong preference for soft sediments where they can partially bury themselves for camouflage and ambush feeding. Big skates demonstrate significant vertical migration patterns, moving between shallow and deeper waters seasonally and throughout their life cycle. Big skates are opportunistic predators that feed on a diverse array of bottom-dwelling organisms including crabs, shrimp, worms, mollusks, and small fish. Their flattened body structure allows them to glide along the seafloor while using electroreception to detect prey buried in sediment. Unlike many fish species, big skates are oviparous, depositing their fertilized eggs in distinctive leathery cases commonly called "mermaid's purses." These egg cases are rectangular with curved horns at each corner and can measure up to 30 centimeters (12 inches) in length. Young skates hatch as miniature adults after an extended incubation period that can last over a year. Reproduction occurs through internal fertilization, with males using modified pelvic fins called claspers to transfer sperm. Females can produce multiple egg cases throughout the breeding season, typically depositing them in areas with adequate current flow and suitable substrate for attachment. Currently, the big skate does not hold federal or state endangered species listing status in California. However, like many elasmobranchs, the species faces potential threats from commercial fishing pressure, habitat degradation, and climate change impacts on ocean conditions. The California Department of Fish and Wildlife rates the species' potential for adult dispersal as moderate, suggesting limited movement patterns that could affect population connectivity. As a cartilaginous fish with slow growth rates and late sexual maturity, big skates are inherently vulnerable to overfishing and require careful management to maintain sustainable populations in California waters.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.