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Pacific Angelshark

Pacific angelshark. Photo courtesy National Marine Fisheries Service
Pacific angelshark. Photo courtesy National Marine Fisheries Service

Squatina californica

This flattened benthic shark ambushes prey from beneath the sand. Unlike rays, angelsharks have tubular tails with asymmetrical caudal (tail) fin and lack a venomous spine.

Order – Squatiniformes
Family – Squatinidae
Genus – Squatina
Species – californica

Common Names

Importance to Humans

Gillnet. Photo courtesy NOAA
Gillnet. Photo courtesy NOAA

In the mid-1980s, they became part of a developing fishery. It was commercially caught with gillnets and recreationally caught by sport spearfishers. However, there is currently a moratorium.

Danger to Humans

Although this shark is a bottom dweller and appears harmless, it possesses powerful jaws. Though there have never been any confirmed attacks, divers should still use caution.

Conservation

Only recently has there been a fishery for these animals off southern California. Currently, there is a large regulated trawl and gillnet fishery. Commercial catch data show that landings of this species went from 166 kg (366 lb.) in 1977 to over 310,000 kg (700,000 lb.) in 1984. However, due to its slow reproductive rate and growth as well as late maturation, this species is vulnerable to overfishing. Currently, the gillnet fishery off California is closed until further notice due to the depletion of the population. A continued fishery would pose a serious threat to this species in U.S. waters. The Pacific angelshark is currently assessed as “Near Threatened” by the IUCN (Fowler et al., 2005; Leet et al., 2001).

 

> Check the status of the Pacific angelshark at the IUCN website.

Geographical Distribution

World distribution map for the Pacific angelshark
World distribution map for the Pacific angelshark

The eastern Pacific Ocean from southeastern Alaska to the Gulf of California and Costa Rica to southern Chile ((Bustamante et al. 2014; Leet et al. 1992, 2001; Natanson and Cailliet, 1986, 1990). Off the coast of California, it is seen occasionally while between Oregon and southern Alaska it is uncommon to rare.

Habitat

This shark, in contrast to many other species, is benthic (bottom dweller). It buries itself in sand or mud bottoms during the day, coming out to actively search for food at night. It is often found on the continental shelf and littoral areas, and sometimes near rock canyons and kelp forests (Feder et al. 1974; Ebert, 2003). Off the coast of California, this angelshark can be found typically at depths of 100 m (328 ft.). The adults have high site fidelity, often resting in the same spot every day (Standora and Nelson, 1977).

Biology

World distribution map for the Pacific angelshark
World distribution map for the Pacific angelshark

Distinctive Features

The Pacific angelshark is dorsoventrally flattened with a terminal mouth at the tip of the snout. The pectoral fins are broad and separated from the head. This characteristic distinguishes angelsharks from the rays, whose pectoral fins are completely attached to the sides of its head. Eyes and spiracles are located on the top of the head, with five pairs of gill slits extending from the side of the head to under the throat. The gill slits of rays are located ventrally. Fleshy nasal barbels and flaps are also located at the snout. This shark lacks anal fins and dorsal fin spines. The two dorsal fins are located on the rear of the body near the base of the tubular tail. The caudal fin is well developed with a longer lower lobe than the upper lobe (Compagno, 2001; Ebert, 2003).

Pacific angelshark. Photo courtesy National Marine Fisheries Service
Pacific angelshark. Photo courtesy National Marine Fisheries Service

Coloration

This species may occasionally be dark brown or grey, splotched with shades of brown and black. These coloration patterns allow the shark to camouflage with mud and sandy bottoms. The ventral side is white and extends to the periphery of the mouth and fins (Compagno et al., 2005).

Dentition

Pointed and conical teeth with smooth edges and broad bases. The upper and lower jaws have 14-18 rows of teeth with large gaps at each symphysis (Ebert, 2003).

Size, Age, and Growth

The maximum length is 118 cm (3.9 ft.) for males and 152 (4.9 ft.) for females, with a maximum, reported age of 35 years (Ebert, 2003). Size of maturity appears to vary by location but usually occurs for both sexes between 76-112 cm, taking anywhere from 8-13 years to mature (Cailliet et al. 1992; Cortes, 2002; Natanson and Cailliet 1986; Romero-Caicedo et al., 2016)

Food Habits
Bony fishes including croakers, halibut, as well as small elasmobranchs. It is also known to consume invertebrates such as crustaceans and mollusks (Ebert, 2003).

Southern stingray - notice that the pectoral fins are completely attached to the head in contrast to angelsharks which have pectoral fins that are separated from the head. Photo © George Ryschkewitsch
Southern stingray – notice that the pectoral fins are completely attached to the head in contrast to angelsharks which have pectoral fins that are separated from the head. Photo © George Ryschkewitsch

During daylight hours, the Pacific angelshark camouflages itself in the sand waiting for potential prey. When a prey item comes within reach, the angelshark ambushes the prey, snatching it up with powerful jaws. After feeding, the shark settles back into the bottom substrate, awaiting another prey item. Feeding usually occurs during nighttime hours when the angelshark cruises over the bottom in search of fish and invertebrates such as squids, octopus and crustaceans (Ebert, 2003; Fouts, and Nelson, 1999).

Reproduction
There is little known about the mating behavior of the Pacific angelshark other than that it probably occurs in early summer. Reproduction takes place via aplacental viviparity. The gestation period is approximately 10 months with birth occurring from March to June. Litter size ranges from 1-13, with the pups measuring 25 cm (9.8 in.) at birth (Natanson and Cailliet, 1986; Ebert, 2006).

White sharks feed on the Pacific angelshark. Photo © Jeremy Stafford-Deitsch
White sharks feed on the Pacific angelshark. Photo © Jeremy Stafford-Deitsch

Predators

Larger sharks, including white sharks (Carcharodon carcharias) as well as northern elephant seals (Mirounga angustirostris) (Ebert, 2003; Sinclair, 1994).

Taxonomy

The Pacific angelshark was described by the first curator of Ichthyology at the California Academy of Sciences, William O. Ayres, in 1859 as Squatina californica. The genus name Squatina is derived from Latin, meaning “a kind of shark”. Other references to this species which may be questionable include Squatina armata Philippi, 1887, Rhina armata Philippi, 1887, and Rhina philippi Garman, 1913. Approximately 15 species of angelshark in the family Squatiniformes which have been described, although there are species existing that have yet to be described.

 

Revised by: Tyler Bowling 2019

Prepared by: Cathleen Bester

 

References