Sharks of Gibraltar
All species
Bigeye Thresher Shark

Bigeye Thresher Shark

Alopias superciliosus

Not aggressive

Identified by enormous upward-facing eyes and a tail nearly as long as the body.

Maximum size

3.4–4.9 m

Aggressiveness

Not aggressive

Habitat

Deep oceanic waters by day (300–500 m), shallower at night.

Ecology

Performs strong daily vertical migrations. Found in the deeper Atlantic-Mediterranean exchange waters off Gibraltar.

Feeding

Stuns schooling fish and squid with whip-like strikes of the elongated upper tail lobe.

Behaviour

Usually solitary; rarely encountered by recreational divers due to depth.

Safety notes for visitors

Risk to swimmers: NegligibleRisk to divers: NegligibleEncounter likelihood: Possible

Species-specific: No recorded attacks on humans. Treat with respect — the tail strike can injure.

If you encounter one

  • Enjoy the sighting — these species are not considered dangerous to humans.
  • Keep a respectful distance; do not touch, grab or attempt to ride the animal.
  • Avoid blocking its path or cornering it against the seabed or a reef.
  • Report unusual or stranded individuals to GONHS or the Department of the Environment.

General visitor guidance

  • Swim, snorkel and dive in groups and stay close to the shore or your boat.
  • Avoid dawn, dusk and night — visibility is low and many sharks are most active.
  • Do not enter the water with open wounds or near fishing activity, bait or chum.
  • Remove shiny jewellery and avoid high-contrast clothing that can resemble prey.
  • If sharks are reported locally, follow guidance from Gibraltar Port Authority and lifeguards.

Conservation status

IUCN: Vulnerable.

Sources & Citations

Data compiled from peer-reviewed and authoritative open sources. Last reviewed 2026.