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Species Database

Prionace glauca - Blue Shark

Blue Shark image

Geographic range:

World-wide

Key features:

Prionace glauca is very slender and fusiform, with a long, conical snout and large eyes. Its body is dark blue above, bright blue on sides, and white below.

Habitat(s):

bay (rocky shore), bay (sandy shore), Continental shelf, continental slope, estuary, kelp forest, pelagic zone
 

Primary common name:

Blue Shark

Synonymous name(s):

Carcharias gracilis, Carcharias hirundinaceus, Carcharias pugae, Prionace mackiei, Squalus caeruleus, Squalus glaucus, Thalassinus rondelettii

General grouping:

Sharks, skates, rays

ITIS code:

160424
 

Geographic Range

Range Description:

Prionace glauca has a worldwide distribution and occupies all temperate and subtropical seas.

Intertidal Height

Lowest intertidal height:

0 meters OR 0 feet

Highest intertidal height:

0 meters OR 0 feet

Subtidal Depth Range

Minimum depth:

0 meters OR 0 feet

Maximum depth:

350 meters OR 1165.5 feet

Habitats

bay (rocky shore), bay (sandy shore), Continental shelf, continental slope, estuary, kelp forest, pelagic zone

Habitat notes:

Prionace glauca primarily occupies offshore and epipelagic waters. They will also venture close inshore, especially at night, or in areas with a narrow continental shelf or off oceanic islands. They are usually at or near the surface, but may be deeper in the tropics and have been found to occupy waters as deep as 350 m. Prionace glauca is more cold-tolerant than others in family and generally occupies water that is between 7 and 21 degrees Centigrade.

Abundance

Relative abundance:

Prionace glauca is common offshore.

Species Description

General description:

Prionace glauca belongs to the Requiem shark family Carcharhinidae in the Order Carcharhiniformes in the Class Chondrichthyes. It is probably the widest ranging chondrichthyan and is the most abundant pelagic shark off the west coast of North America. The genus name, Prionace is Greek for saw point, probably referring to their serrated teeth and the species name, glauca is Greek for blue.

Distinctive features:

Prionace glauca is a very slender and fusiform shark with a long, conical snout and large eyes. Its body is dark blue above, bright blue on sides and white below. The tips of the pectoral, dorsal and anal fins are dusky. The pectoral fins are very long, narrow, and somewhat falcate while the dorsal fins are relatively small with no dermal ridge. The caudal fin is falcate and the keel on the caudal peduncle is weak. The teeth are serrate, triangular and curved in the upper jaw, while they are narrower in the lower jaw.

Bonito Sharks, Isurus oxyrinchus, resemble Prionace glauca but can be distinguished by their acutely pointed snout, longer gill slits, smooth teeth, wide caudal keel, crescent-shaped caudal fin, and their heavier body. Soupfin Sharks, Galeorhinus zyopterus, can be differentiated from Prionace glauca by their notched teeth and the black anterior edges of their dorsal fins. Gray sharks, Carcharhinus sp., are different from Prionace glauca in their gray or brownish stout bodies, and their lack of a caudal keel.

Size:

Prionace glauca can grow to a length of 4 m and weigh as much as 206 kg, though most are less than 1.8 m. At birth, the young are only about 48 cm.

Natural History

General natural history:

Prionace glauca may occur alone or in aggregations. Evidence exists that this species may even form single-sex aggregations, where all the fish in one area are either male or female. They seem to be most active at night and in some areas they stay offshore and near the surface by day, then move inshore at night, perhaps to feed, and move offshore again in the morning. They may travel considerable distances as exemplified by one specimen tagged in New Zealand that was recaptured 1,200 km off the coast of Chile. Their maximum age has not been determined, though estimates indicate they likely live to about 20 years. Prionace glauca is considered potentially dangerous since there have been a few reported attacks on humans and they sometimes harass divers.

Predator(s):

Bonito Sharks, Isurus oxyrinchus, California Sea Lions, Zalophus californianus, and Northern Elephant Seals, Mirounga angustirostris, all prey on Prionace glauca. This species is caught commercially in the Northeast Atlantic with pelagic longlines, hook and line, pelagic trawls and bottom trawls. Conversely, in the Eastern Pacific this species has traditionally been considered a nuisance to fishermen, though recently a few recreational vessels have begun to run trips targeting them. They are likely caught recreationally worldwide and are also common bycatch in high-seas longline and driftnet fisheries.

Prey:

Prionace glauca feeds on a wide variety of fishes and invertebrates. Some of their common prey items include anchovies, pipefishes, Blacksmiths, Chromis punctipinnis, dogfish, Slender Soles, Lyopsetta exilis, cuskeels, Sanddabs, Citharichthys sp., sauries, lanternfish, salmon, squid, Pelagic Red Crabs, Pleuroncodes planipes, cetacean carrion, occasionally seabirds, offal and even garbage.

Feeding behavior

Carnivore, Scavenger

January - November

Migration:

Prionace glauca is considered a highly migratory species, though the full extent of their migrations is not known. They may be present throughout the year in some areas, but tend to migrate northward in the summer as coastal oceans warm.

Reproduction:

Prionace glauca are viviparous and produce up to 135 pups a year. The number of young varies more in this species than any other livebearing shark and may be dependent on the size of the female. Most mating occurs in late spring to early winter with young being born in spring to early summer of the following year. In tropical areas, however, these sharks may mate throughout the year. Studies show that mature females can store sperm for many months before fertilizing their eggs. Once they do fertilize, gestation lasts for 9 12 months. Females often have bite marks on their backs caused by males biting them as a part of mating behavior. As a result, adolescent and adult females develop skin that is about three times as thick as males, and thus the bites are not damaging. Prionace glauca matures at about 2 m in size and 7 years of age.
  • Tagging of Pacific Predators (TOPP)

    The Tagging of Pacific Pelagics (TOPP) research program aims to understand the migration patterns of large predators in the North Pacific basin and how these animals act and interact in their open ocean habitats. By using satellite tagging techniques, TOPP researchers follow the movements of different species across multiple trophic levels (i.e., the food web) and in relation to physical oceanographic features in order to piece together a whole ecosystem picture. [View Project]

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Eschmeyer, W.N., and E.S. Herald. 1983. A Field Guide to Pacific Coast Fishes of North America. Houghton Mifflin Company, Boston, MA. 336 p.
Food and Agriculture Organization of the United Nations. 2004 (Updated 06/29/04). A world overview of species of interest to fisheries, Species Fact Sheet. http://www.fao.org/figis/servlet/static?dom=root&xml=species/species_search.xml, Accessed [09/26/06].
Froese, R. and D. Pauly (eds.). 2006 (Updated 01/02/06). FishBase. World Wide Web electronic publication. http://www.fishbase.org, Accessed [04/25/06].
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Love, M. 1996. Probably more than you want to know about the fishes of the Pacific Coast. Really Big Press, Santa Barbara, CA. 381 p.