The Swift and Powerful Shortfin Mako Shark
By Ayane Inuzuka-Boyle
Located in Nova Scotian waters, the shortfin mako shark (Isurus oxyrinchus) may not steal the spotlight like species such as the great white shark, but it’s an impressive predator in its own right. As the fastest shark species, the shortfin mako can reach burst speeds of up to 68 kilometers per hour!
Mature makos can grow to lengths of up to 3.9 meters (12.8 feet). They are identified by their spindle-shaped bodies, pointed snouts, and long, slender teeth. Makos also have distinct countershading, a form of camouflage that helps them blend into their surroundings. Their deep blue backs transition into a white underside, with a metallic blue band running along their sides. In Atlantic Canada, shortfin makos are often mistaken for porbeagle sharks, which have a similar appearance.
Shortfin makos have a widespread distribution in temperate and tropical waters. In Canadian waters, they can be found along the continental shelf of Nova Scotia and into the Gulf of St. Lawrence. They are a highly migratory species and can cross entire oceans! To maintain their body temperatures during these long migrations, they use countercurrent heat exchange, a mechanism that uses the heat generated by their swimming muscles to warm their blood.
Adult shortfin mako with countershading (Image credit: https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/isurus-oxyrinchus/)
As opportunistic apex predators, shortfin makos feed on a variety of prey such as squid, bony fishes, porpoises, sea turtles, and even other sharks! Their role as a top predator makes them important in maintaining the structure of marine ecosystems.
Thanks to their incredible speed, shortfin makos have very few natural predators. However, they face significant threats from human activity. They are often unintentionally caught as bycatch in fisheries or targeted for their highly valued meat. While regulations in Canada prohibit directly targeting makos, stronger advocacy and conservation efforts are important to reduce bycatch and ensure healthy populations of these sharks in Atlantic Canada. In 2021, the World Wildlife Federation (WWF) initiated a rebuilding programme to allow the recovery of the endangered mako shark in the North Atlantic. WWF sees the plan as the most efficient way to immediately stop the overfishing and dramatic decline of shortfin mako sharks and set the species on a path towards recovery.
Ayane recently finished her undergraduate degree in marine biology at Dalhousie University. Originally from British Columbia, she has embraced life on the East Coast and developed an appreciation for the local marine environment. With a passion for marine conservation, she is eager to share her knowledge and inspire others to care for the ocean.