Basking Shark

The basking shark is the second-largest fish in the world, reaching lengths of up to 10 meters, distinguished by its enormous gaping mouth used for filter-feeding on plankton. Despite its size, it is a slow-moving, docile species, often observed swimming at the surface with its mouth open, straining zooplankton and small fish through gill rakers. As a filter feeder, it plays a role in regulating plankton populations and serves as an indicator species for productive marine ecosystems.

This shark has a wide but patchy distribution, occurring in temperate and boreal waters across the Atlantic and Pacific Oceans, from Canada, the United States, and the United Kingdom to Chile, New Zealand, and Japan, among many other coastal nations. It inhabits marine oceanic and coastal environments, often near continental shelves, and undertakes seasonal migrations, sometimes across ocean basins, tracking plankton blooms.

The species is classified as Endangered, with a decreasing population trend. Historically, it was heavily targeted for its liver oil, fins, and cartilage, which caused severe population declines in some regions. Today, ongoing threats include bycatch and entanglement in fishing gear, as well as collisions with vessels in busy shipping lanes, given its surface-dwelling habits and slow swimming speed.

Conservation measures include international trade restrictions under CITES Appendix II, protections under regional agreements such as the Convention on Migratory Species, and national-level fishing bans or landing prohibitions in several countries. Some critical habitats have been designated as protected areas or seasonal management zones to reduce vessel strikes.

Given its slow reproductive rate, long lifespan, and continued exposure to fishing and shipping pressures, recovery is expected to be slow even where protective measures are enforced, and the species remains vulnerable to further decline without sustained international cooperation.