Basking Shark

Basking Shark battle analysis

The basking shark spends summer days at the surface with its mouth stretched open like a giant net, straining tiny copepods from the water. An average adult is about 7.9 metres long and weighs around four tonnes, yet it feeds at a slow walking pace and barely reacts to passing boats. That calm made it an easy target for centuries of harpoon fisheries hunting its oily liver.

Its lazy image hides surprising power. Loggers attached to basking sharks show them rushing up from around 20 metres and leaping clear of the sea at about 5 m/s, the same vertical speed as a great white shark, and doing so hundreds of times a year. Satellite tags show them crossing oceans and even the equator, diving hundreds of metres into the twilight zone and staying there for weeks.

In a battle, the basking shark is a pure endurer. It has no bite worth the name and no inclination to fight, but its thick, abrasive skin and massive body make it a very hard target for anything smaller than a killer whale. Orcas, working together, are the one predator known to take them, and against such opponents its only real options are its bulk and a dive into deep water.

Habitat & range

Basking sharks live in boreal to warm-temperate waters around the world, on continental shelves and in the open ocean, and occasionally enter brackish water. They prefer water of about 8–14.5 °C, are often seen at the surface in summer at hotspots such as western Scotland, the Isle of Man and the continental shelf off the north-east United States and Canada, and move deeper, to about 900 m, in winter. Some cross the tropics at depth.

Diet & hunting

A filter feeder on zooplankton, especially calanoid copepods, along with fish eggs, larvae and small invertebrates. It feeds selectively in the densest plankton patches, often along ocean fronts, and continues foraging during long migrations, including in the deep scattering layers of the mesopelagic.

Social life

Usually solitary but gathers in summer where plankton is dense. It forms small sex-segregated groups, and courtship tori of several sharks circling together have been documented in the eastern North Atlantic.

Conservation

Listed as Endangered on the IUCN Red List (2019, amended 2021) and on CITES Appendix II. Centuries of harpoon and net fisheries for its liver oil, fins and meat collapsed several populations. It is fully protected in the United Kingdom and in the Atlantic and Gulf of Mexico waters of the United States.

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