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No Records
Occasional
Range

Map base conforms with ICES grid squares.

Blue Shark, Blue Dog, Blue Whaler, Peau Bleue (Fr), Tiburón Azul (Es).

Squalus glaucus (Linnaeus, 1758), Squalus adscentionis (Osbeck, 1765), 
Squalus rondeletii (Risso, 1810), Squalus caeruleus (Blainville, 1825), 
Galeus thalassinus (Valenciennes, 1835), Thalassorhinus vulpecula 
(Valenciennes, 1838), Carcharias hirundinaceus (Valenciennes, 1839), 
Thalassinus rondelettii (Moreau, 1881), Carcharias pugae (Perez Canto, 
1886), Carcharias gracilis (Philippi, 1887), Hypoprion/Hemigaleus isodus 
(Philippi, 1887), Carcharias aethiops (Philippi, 1896), Prionace macki 
(Phillipps, 1935).

COMMON NAMES

• 

Slender body.

• 

Long, rounded snout.

• 

Very long, pointed pectoral fins.

• 

First dorsal fin closer to pelvic fins than pectoral fins.

• 

Second dorsal fin equal in size to and directly above anal fin.

• 

Caudal fin non lunate with a large terminal lobe.

The Blue Shark is a large, slender-bodied requiem shark with a long, 
narrow snout. The first dorsal fin originates well behind the pectoral 
fin free tips in individuals over 100cm. The pectoral fins are long and 
curved. The second dorsal fin is roughly equal in size to the anal fin, 
over which it is positioned. The dorsal lobe of the caudal fin is larger 
than the ventral lobe and has a terminal lobe which covers less than a 
third of its length (Compagno, 1984).

It is a distinct metallic blue on the back and flanks, ventrally it is 

pure white. This counter-shading provides some camouflage in the 
open ocean. It reaches a maximum size of 383cm (Cooper, Unknown)

Possibly the widest 
ranging of all 
chondrichthyans, 
the Blue Shark is 
found in temperate 
and tropical waters 
worldwide. In the 
east Atlantic it is 
found from Norway 
to South Africa, 
Including the 
Mediterranean. It 
is also found in the 
west Atlantic Ocean, 
the whole Pacific 
Ocean and the 
whole Indian Ocean 
(Kohler et al., 2002; 
Cooper, Unknown).

SYNONYMS

DISTRIBUTION

APPEARANCE

BS

H

Lateral View (

♀)

Text & Illustrations © Shark Trust 2009

Ventral View (

♀)

Blue Shark

Prionace glauca

N

T

N

AT

M

ED

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SIMILAR SPECIES

Carcharhinus falciformis, Silky Shark
Isurus oxyrinchus, Shortfin Mako Shark
Isurus paucus, Longfin Mako Shark
Lamna nasus, Porbeagle Shark
Galeorhinus galeus, Tope

 

Blue Shark

Text & Illustrations © Shark Trust 2009

(Not to scale)

Supported by:

Prionace glauca,
Blue Shark

Isurus oxyrinchus,
Shortfin Mako Shark

Isurus paucus,
Longfin Mako Shark

Lamna nasus,
Porbeagle Shark

Galeorhinus galeus,
Tope

Carcharhinus falciformis,
Silky Shark

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Blue Shark 

Prionace glauca

TEETH

The upper teeth are triangular and curved 
with serrated edges and overlapping 
bases. There is a symmetrical symphysial 
tooth with 14 teeth either side. The lower 
teeth are nearly symmetrical with fine 
serrations and there are 13–15 teeth either 
side (Cooper, Unknown).

HABITAT

A pelagic species, the Blue Shark can be found from the surface to at 
least 600m. It has a preference for temperate and subtropical waters 
from 12–20

o

C but can tolerate temperatures from 8–29.5

o

C. The Blue 

Shark is found in the tropics but tends to seek cooler water at depth 
(Kohler et al., 2002). In the tropical Indian Ocean the temperature 
can fall from 25

o

C at 80m to 12

o

C at 220m (Cooper, Unknown).

In the North Atlantic, tag and recapture studies have shown 

that a regular clockwise trans-Atlantic migration occurs following 
the major currents. It appears that sharks tagged off the east coast 
of the USA follow the Gulf Stream to Europe, ride various currents 
south along the coasts of Europe and Africa and then follow the 
Atlantic North Equatorial Current to the Caribbean. Because of this, 
the entire North Atlantic population is considered a single stock. 
There have been reports of tagged sharks crossing the equator 
into the South Atlantic. While this appears to be a rare occurrence, 
it shows that there is some genetic exchange between the two 
areas. There is considerable sexual segregation in populations with 
females more abundant at higher latitudes than males (Kohler et al., 
2002).

DIET

The diet of the Blue Shark consists mainly of small pelagic fish and 
cephalopods, particularly squid. However, invertebrates (mainly 
pelagic crustaceans), small sharks, seabirds and cetaceans (possibly 
carrion) are also taken. Most of the prey is pelagic although bottom 
fishes are also found in stomach contents. It appears to feed 24 
hours a day with increased activity in the early evening and at night 
(Stevens, 2000).

REPRODUCTION

The Blue Shark reproduces through placental, or yolk-sac, viviparity. 
At the start of the gestation period, the embryos are nourished by a 
yolk supply in a very similar way to the 60% of elasmobranchs which 
reproduce vivipariously. However once this yolk supply is used up the 
yolk-sac changes, becoming more folded and wrinkled. It can now 
interlock with the lining of the mother’s uterus. The blood supply to 
both the yolk-sac and the uterus wall increases allowing nutrients 
and oxygen to pass from the mother to the embryo and vice versa for 
waste, very much like a mammalian placenta (Martin, 1994).

Males are believed to reach sexual maturity between four and five 

years of age at a length of 182–291cm. Females mature later between 
five and six years at a length of 221–323cm (Cooper, Unknown). In 
temperate waters, mating occurs from late spring to early winter. 
Gestation varies from 9–12 months and young are born in spring 
to early summer. In tropical seas, mating is thought to occur all 
year round (Compagno, 1984). The number of young born is highly 
variable with litters from 4–135 pups recorded, although the average 
is around 35. These pups measure 35–50cm in length and remain in 
nursery areas for the first few years of life, during which they grow 
rapidly. It appears that for Atlantic sharks, the Mediterranean is an 
important nursery area (Kohler et al., 2002).

Text & Illustrations © Shark Trust 2009

ECOLOGY AND BIOLOGY

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COMMERCIAL IMPORTANCE

Thought to be the most heavily fished shark, the Blue Shark is 
mainly taken as bycatch in pelagic longlines but also in pelagic 
trawls, hook and line and bottom trawls inshore (Compagno, 1984). 
Keeping the meat is difficult as it ammoniates quickly, therefore 
the vast majority are discarded at sea after their fins are removed 
for sale in the Asian fin trade (Cooper, Unknown). When it is landed 
whole its flesh can be used for human consumption, its liver for oil, 
its carcass can be processed for fishmeal and its hide can be used for 
leather (Compagno, 1984).

IUCN RED LIST ASSESSMENT

Near Threatened (2000).

Thought to be one of the most abundant and widespread large 
animals on the planet, the Blue Shark is heavily fished throughout 
its range by pelagic longlines and hook-and-lines. Its flesh is not 
highly valued but its fins are, meaning many Blue Sharks are finned 
at sea and subsequently discarded. It is also considered a game fish 
and large numbers are taken by recreational anglers every year, 
although many now return the sharks they catch alive (Stevens, 
2000).

In the northeast Atlantic, the Blue Shark is covered by EC 

Regulation No. 1185/2003 which prevents the removal of fins at sea 
and the subsequent discard of the body. This applies to all vessels 
operating in EC waters, as well as to EC vessels operating anywhere 
(CPOA Sharks, 2009). However, loopholes in this legislation allow 
many fishing boats to continue this practice. In addition, as it is a 
highly migratory species, localised legislation may have little effect 
on wider populations.

While the Blue Shark is relatively highly fecund and has a wide 

range which buffers it from the effects of heavy fishing pressure, 
population declines are still being observed across its range. 
Catches need to be monitored and legislation needs to be created, 
changed or enforced if population declines are to be halted 
(Stevens, 2005).

•  Handle with care.
•  Large shark with powerful jaws and sharp teeth.
•  Abrasive skin.

 

Blue Shark

Text & Illustrations © Shark Trust 2009

Supported by:

THREATS, CONSERVATION, LEGISLATION

HANDLING AND THORN ARRANGEMENT

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COMPAGNO, L. J. V. 1984. FAO Species Catalogue, Vol. 4, Part 2, 

Sharks of the World: An Annotated and Illustrated Catalogue of 
Shark Species Known top Date. FAO. Rome, Italy.

COOPER, P. Unknown. Blue Shark. Florida Museum of Natural 

History. http://www.flmnh.ufl.edu/fish/.

KOHLER, N. E., TURNER, P. A., HOEY, J. J., NATANSON, L. J., BRIGGS, J. 

2002. Tag and Recapture Data for Three Pelagic Shark species: 
Blue Shark (Prionace glauca), Shortfin Mako (Isurus oxyrinchus), 
and Porbeagle (Lamna nasus) in the North Atlantic Ocean. Col. 
Vol. Sci. Pap. ICCAT, 54 (4): 1231–1260.

MARTIN, R. A. 1994. From Here to Maternity. Reefquest Centre for 

Shark Research. www.elasmo-research.org.

STEVENS, J. 2000. Prionace glauca. In: IUCN 2008. 2008 IUCN Red 

List of Threatened Species. www.iucnredlist.org.

STEVENS, J. 2005. Blue Shark: Prionace glauca (Linnaeus, 1758). In: 

Fowler, S. L., Cavanagh, R. D., Camhi, M., Burgess, G. H., Cailliet, 
G. M., Fordham, S. V., Simpfendorfer, C. A., Musick, J. A. 2005. 
Sharks, Rays and Chimaeras: The Status of the Chondrichthyan 
Fishes. IUCN SSC Shark Specialist Group. Cambridge, UK.

REFERENCES

Blue Shark 

Prionace glauca

Text & Illustrations © Shark Trust 2009

Text: Richard Hurst.
Illustrations: Marc Dando.

Citation
Shark Trust; 2010. An Illustrated Compendium of Sharks, Skates, Rays 
and Chimaera. Chapter 1: The British Isles and Northeast Atlantic. Part 
2: Sharks.

Any ammendments or corrections, please contact:
The Shark Trust
4 Creykes Court, The Millfields
Plymouth, Devon PL1 3JB

Tel: 01752 672008/672020

Email: enquiries@sharktrust.org

For more ID materials visit www.sharktrust.org/ID.

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