The unusual, very distinctive Angel Shark, Squatina squatina, was once very common in the North East Atlantic, from Mauritania to Norway; throughout the North Sea; in the Mediterranean and the Black Sea. Today, it is already extinct in some areas - including its former habitats in the North Sea - and is listed as critically endangered everywhere else. Up to now, this magnificent creature was still fairly common in its last stronghold around the Canary Islands, but even there, its numbers are now seriously threatened.
The wide pectoral fins and flattened front section of the Angel Shark's body make it look more like a skate or ray than a shark, although its body's rear section is more like a typical shark's rear end. Its skin colour ranges from grey to greenish or reddish brown. While young Angel Sharks may feature net-like white markings and comparatively large dark blotches, adults are typically a little plainer, featuring a scattering of small white spots and some blackish dots. The back of the Angel Shark may also feature some lines - slightly lighter than the main colouring - that mimic tidal ridges in the sand.
The blackish dots covering the back of the shark tend to join in the middle of the pectoral fins, creating dark bands, and the dark leading edge of the dorsal fins is trailed by a paler edge. Like other mid-water feeders, the Angel Shark has a so-called terminal mouth (opening at the head's front, with equal lower and upper jaws). It also features a pair of nasal skin flaps and nasal barbells - whisker-like projections - which it uses to feel and taste.
Vertical slit pupils within its round, large eyes provide this creature with excellent all-round vision, making it a very efficient ambush predator. At birth, an Angel Shark is usually around 24 to 30 cm (0.8 to 1 ft) long. Females will grow to reach a mature length of between 126 and 167 cm (4.1 to 5.5 ft), while adult males can be 1.83 to 2.24 m (6 to 7.3 ft) in length.
Biology, Behaviour and Habitat
Angel Sharks occur in temperate waters, preferably in areas with sandy or muddy sea floors. They can be found at depth from 5 m (16.4 ft) inshore (estuaries, coast line) up to 150 m (492.1 ft) or more along the continental shelf, although they are seasonally migratory and will disappear from the majority of shallower areas during the summer. During this period, they can occasionally be found in larger numbers in bays situated on the northern end of Gran Canaria.
Being nocturnal, the Angel Shark will typically only swim off the bottom during the night, and is torpid during the day. It will find a resting place, where it uses its pectoral fins to dust away sufficient sand or mud to create a depression within which it can settle. From this position, with just its eyes protruding from the sand/ mud, it ambushes its prey. Once an unsuspecting creature - predominantly crustaceans, flatfish, mollusks and skates - swims by, the shark bursts out of its hiding position at incredible speeds and snaps it up. When hunting is good, the shark may stay in its chosen spot for prolonged periods.
Angel Sharks are ovoviviparous, which means their young develop inside eggs that remain within the female's body until the young are ready to hatch. Gestation typically takes between 8 and 10 months, at the end of which the female will give birth to a litter of 7 to 25 pups, depending on the size of the female. The larger the female is, the larger her litter is likely to be.
This species is not particularly important to fisheries, with only a fairly small number being caught for human consumption, fish-meal and perhaps oil, predominantly around Tunisia. The real threat to this lovely creature is more or less accidental - many specimens end up as by-catch of the fishing industry. Their habit of lying in wait at the bottom makes them especially vulnerable to trawl fishing, which has significantly increased over the past 50 years and has resulted in dramatic reductions of Angel Shark populations, with complete extinction in some areas.
Bottom long-lines and trammel nets, as well as tuna traps, also pose a danger to this species, and habit degradation - especially around coastal areas - caused by human disturbance further lead to a decline in numbers.
Already protected within three marine reserves in the Balearic Islands, more and more countries - including the UK and Belgium - are beginning to recognise the need to protect this animal and are taking appropriate steps towards this goal. The Canary Islands, the southern Mediterranean and several other areas, however, still need to confirm the species' status and take action.
This is particularly urgent in the Canary Islands, one of the last remaining Angel Shark strongholds, where unsustainable, destructive fishing methods, coastal habitat degradation on pollution not only threaten this species, but the whole ocean Eco-system. Having already lost the Mediterranean monk seal - the rarest seal in the world - the government of the Canary Islands must take steps now to protect this and other threatened species before it is too late. At time of writing, readers are/ were able to sign a petition to this effect at the Petition Site.