Kitefin Shark

The kitefin shark is a medium-sized deepwater shark, typically reaching lengths of around 1.4 to 1.6 meters, with a slender brownish body, a short blunt snout, and large green-glowing eyes adapted to low-light conditions. It is notable for its bioluminescent underside, produced by photophores, which is thought to aid in counter-illumination camouflage against predators below. As an opportunistic predator and scavenger, it feeds on bony fishes, smaller sharks, cephalopods, and crustaceans, playing a role as a mid-to-upper trophic level consumer in deep marine food webs.

This species has a wide but patchy distribution across tropical and temperate oceans, typically found along continental and insular shelves and slopes at depths ranging from around 200 meters to over 1,800 meters. It has been recorded in waters off numerous countries spanning the Atlantic, Pacific, and Indian Oceans, including Ireland, Portugal, Spain, Japan, Australia, New Zealand, and numerous West African nations, reflecting a broad but fragmented deepwater range.

The primary threat to the kitefin shark is commercial fishing, both as bycatch in deepwater trawl and longline fisheries and, historically, as a target species for its liver oil, rich in squalene. Its slow growth, late maturity, and low reproductive output make populations highly vulnerable to overexploitation and slow to recover.

Conservation measures include regional deepwater fishing depth restrictions and bycatch reporting requirements in parts of its range, along with listing under some regional fisheries management frameworks. Enforcement and data collection remain inconsistent across its range. Given continued fishing pressure and limited recovery capacity, the population trend remains decreasing, with the species' long-term outlook dependent on stronger, more consistent management of deepwater fisheries.