The Pacific angelshark inhabits shallow, coastal waters on sandy flats, usually near rocky reefs, kelp forests, or other underwater features.

Characteristic features of this shark include a pair of cone-shaped barbels on its snout, angular pectoral fins, and a brown or gray dorsal coloration with many small dark markings.

An ambush predator, the Pacific angelshark conceals itself on the sea floor and waits for approaching prey, primarily bony fishes and squid.

The International Union for Conservation of Nature (IUCN) has assessed this species as Near Threatened, as the Californian population is largely protected and recovering, while the impact of Mexican fisheries is unknown.

[4][5] The taxonomic status of angel sharks in the southeastern Pacific – whether they are S. californica, S. armata, or if there is more than one Squatina species in the region – remains unresolved.

This bottom-dwelling shark prefers habitats with soft, flat bottoms close to shore, such as estuaries and bays, and are often found near rocky reefs, submarine canyons, and kelp forests.

[3] These subpopulations have diverged from one another over time because Pacific angelsharks do not undertake long migratory movements outside of their preferred home areas, and deep waters serve as effective geographical barriers to population mixing.

[2] During the day, Pacific angelsharks are almost never seen in the open, instead resting motionless on the sea floor buried under a thin layer of sediment that disguises their outlines.

[15] A sedentary ambush predator, the Pacific angelshark feeds mainly on bony fishes, including kelp bass, croakers, flatfishes, damselfishes, mackerels, and sardines.

[3] In the southern Gulf of California, the most important prey species are, in descending order, the mackerel Decapterus macrosoma, the toadfish Porichthys analis, the lizardfish Synodus evermanni, the soldierfish Myripristis leiognathus, and the shrimp Sicyonia penicillata.

They tend to face upslope, which may facilitate burying via falling sediment, bring more fish swimming downstream from the reef, or ease targeting by silhouetting prey against the sunlight.

As the local prey eventually learn to avoid the stationary predator, the shark periodically shifts at night to a new site several kilometers away.

[10][17] The Pacific angelshark is primarily a visual hunter; experiments in nature show that they strike at fish-shaped targets without any electrical, chemical, vibrational, or behavioral cues.

[3] The strike is a stereotyped behavior in which the shark presses the forward lobes of its pectoral fins against the bottom and thrusts its head upwards at up to a 90° angle.

Its mouth forms a tube when opened, creating a suction force, while its jaws protrude forward to secure the prey between sharp teeth.

[10] The Pacific angelshark is aplacental viviparous with the unborn young nourished by a yolk sac; reproduction occurs on an annual cycle.

[18] Off Santa Barbara, birthing takes place from March to June after a gestation period of ten months, and the females mate again shortly afterward.

[17] Although usually sedate and approachable underwater, Pacific angelsharks are quick to bite if touched, captured, or otherwise provoked, and can inflict severe lacerations.

[20] In 1976, the commercial gillnet fishery for the California halibut (Paralichthys californicus), operating off Santa Barbara, expanded to include the Pacific angelshark as well.

[20][21] In 1991, the use of gillnets in nearshore Californian waters was banned by a voter initiative (Proposition 132); the restricted area included much of the Pacific angelshark's habitat and reduced fishing pressure on the species.

As a result, Pacific angelshark landings dropped further to 10,000 kg (22,000 lb) dressed in 1994, when the central Californian halibut/angel shark fishery was closed completely, and have remained low since.

The decline of the Californian fishery led to the industry shifting to Mexico, where gillnet pangas (artisanal fishing vessels) targeting this species now meet most of the angel shark demand in California.

[20][21] The International Union for Conservation of Nature (IUCN) has assessed this species as Near Threatened; Pacific angelshark numbers off California appear to be increasing and demographic modeling suggests the stock is healthy.