Cartilaginous fish · Squaliformes · Etmopteridae

Velvet-belly

Etmopterus spinax

Least Concern

The species is abundant and widely distributed; it faces no significant short-term risk. See full glossary

The velvet belly lanternshark is a small deep-water shark of the Atlantic and the Mediterranean, present in Spanish waters. It is bioluminescent: its belly is covered in thousands of photophores that emit a bluish light. That light is not for seeing but for disappearing: it matches the dim light coming from above and erases its outline.

Weight

300 g – 1 kg

Size

30 cm – 60 cm

Lifespan

20 years

Diet

Carnivore

Feeds mainly on other animals.

Activity

Nocturnal

Active mainly at night.

Social structure

School

Gathers in coordinated schools, typical of fish.

Sighting difficulty

Easy

OceanCarnivore Nocturnal In schools Fish Ocean

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Fun facts

It lights itself up in order to become invisible: the photophores on its belly emit exactly the same intensity of bluish light as reaches it from the surface, erasing its outline for any predator looking up from below. It is called counter-illumination.
It adjusts the brightness with hormones: it can regulate the intensity of its light to match the changing gloom with depth and time of day.
It lives in Spanish waters, on the slopes of the Bay of Biscay, Galicia and the Mediterranean, and is a frequent bycatch of deep-sea trawling.

Life cycle & biology

Skeleton type: Vertebrate - cartilaginous skeleton (fish)
Habitat & environment: Continental slopes of the eastern Atlantic and the Mediterranean, between 200 and 2,000 metres
Birth weight: 12 - 14 cm at birth
Size at birth: 12-14 cm at birth; it is ovoviviparous
Sexual maturity: 5 years
Gestation / incubation: Internal gestation
Litter / clutch size: 6.8 (average)

Sources consulted: https://es.wikipedia.org/wiki/Etmopterus_spinax

Where to find it

See its range on the interactive map

Best time: All year round on the continental slope of the eastern Atlantic and the Mediterranean, between 200 and 1,000 m; it gives off light from photophores on its underside.