LAST UPDATED: 01.07.2023
LAST UPDATED: 01.07.2023
PORBEAGLE SHARK
PORBEAGLE SHARK
Lamna nasus
Lamna nasus
The porbeagle is a coastal and pelagic shark species found in the cold-temperate waters of the North Atlantic, as well as in the southern hemisphere. Like other members of the family Lamnidae, it is endothermic (warm-blooded), allowing it to maintain high activity levels in the cold waters of Atlantic Canada and the St. Lawrence.
The porbeagle is a member of the mackerel sharks, which includes the white shark, the mako, and the extinct megalodon. These sharks share the same general shape, which oftens leads to misidentification, especially when observed from a boat.
Contrary to recent news headlines associating the porbeagle’s presence with global warming, this shark has long been a regular visitor to the St. Lawrence Gulf and Estuary where it is frequently mistaken for the white shark or shortfin mako. All mackerel sharks are very fast swimmers capable of lightening bursts of speed¹. The porbeagle’s closest relative is its North Pacific cousin, the salmon shark (Lamna ditropis).
¹ Jensen, C., L. Natanson, H.L. Pratt Jr, N.E. Kohler, and S.E. Campana. 2002. The reproductive biology of the porbeagle shark (Lamna nasus) in the western North Atlantic Ocean. Fishery Bulletin 100(4):727-738.
Order – Lamniformes
Family – Lamnidae
Genus – Lamna
Species – L. nasus
NAMES
NAMES
Scientific name: Lamna nasus
Common names: Porbeagle shark, Atlantic mackerel shark, Beaumaris shark, bottle-nosed shark, blue dog.
Mi’kmaw names: Sabbede-mequ, siglati, tan booskekŭlooskăbāwit’, webetŭmâk’, wipitmeqw.
French common names: Requin maraîche, requin de fond.
The porbeagle’s common name may be a combination of ‘porpoise’ and ‘beagle,’ referencing the shark’s appearance and hunting behaviour.
GENERAL DESCRIPTION
GENERAL DESCRIPTION
• Average length of 1.5 to 2.5 metres in Atlantic Canada and Québec.
• Blue-grey above and white ventral side.
• Streamlined yet stocky body with a cone-shaped snout and large black eyes.
• Distinctive white blotch at the rear base of the first dorsal fin.
• Pectoral fins feature black tips on the ventral surface.
• Second dorsal fin much smaller than first.
• Blade-shaped teeth with lateral cusplets, i.e. tiny projections on each side of the tooth.
• Upper and lower lobes of the tail nearly identical in size.
• Seasonal presence in Atlantic Canada and Quebec, including the St. Lawrence Estuary.
DISTRIBUTION
DISTRIBUTION
The porbeagle shark is found throughout the entire Gulf of St. Lawrence and into the Estuary to La Malbaie. The most northerly confirmed observation was reported in Nain, Labrador. The porbeagle arrives in the St. Lawrence in early summer and has mostly departed by November. The duration of its annual migration to the St. Lawrence may be affected by warmer conditions resulting from climate change.
(BELOW) Provisional distribution of the porbeagle shark, Lamna nasus, in the St. Lawrence and Atlantic Canada, based on research by the St. Lawrence Shark Observatory. Porbeagle shark observations have recently become so frequent that only historical and select cases are posted to illustrate overall range. This map is updated with new and historical data on an ongoing basis. Map does not include data from the U.S. except borderline cases. To submit additional sightings or captures, please contact us. Click on icons for observation details.
ATTACKS
ATTACKS
According to the Canadian Shark Attack Registry, the porbeagle shark has been involved in one confirmed incident with a human in Canada, as well as one borderline case in Maine. In both cases, the shark may have initially been attracted to the site of the incident by the scent trail produced fresh bait or attractants produced by human activity. The porbeagle is primarily a fish-eater, hence any confrontation with human may be the result of territorial behaviour or overstimulation caused by the presence of attractants.
¹ Gallant, J. (2022. July 26). Canadian Shark Attack Registry (1st ed.). St. Lawrence Shark Observatory. https://geerg.ca/en/shark-attacks
FISHERIES
FISHERIES
None. The directed commercial fishery for the porbeagle shark in Atlantic Canada was discontinued in 2013 due to dwindling stocks.
CONSERVATION STATUS
CONSERVATION STATUS
The porbeagle shark is listed as an endangered species by COSEWIC (Committee on the Status of Endangered Wildlife in Canada).
Jeffrey Hay Gallant, MSc, is the founder and Scientific Director of the St. Lawrence Shark Observatory (ORS) and a doctoral researcher at UQAM. He made his first shark observation at Peggy’s Cove in 1975, first shark dive off Chebucto Head in 1992, co-led the first Canadian cage dives off Halifax in 2000, and was the first person to film a free-swimming Greenland shark in 2003.
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