SHARKS

There are two family groups of fish, the elasmobranchs, which are cartilaginous and include all the sharks and rays and the teleosts, which are all other bony fishes.

Sharks are a highly specialized and ancient family present in the Mediterranean and although the species are principally represented by the cat sharks, which are not harmful to man, there are great white sharks to be found. All sharks eat living animals, but many also eat decaying matter. Most are active hunters at night and all are shy. They are able to detect low-level electrical currents and can find sleeping fish at night. With highly developed sensory ampullae, they are able to detect low-frequency vibrations from great distances as well as scent from injured or dying animals.

SAND TIGER SHARK

Carcharias taurus

The Sand Tiger Shark or Ragged-tooth Shark, up to 3.30m (11ft) long, prefers deeper water where it feeds on a variety of bony fish and crustaceans. Although very fearsome looking, it is not known to attack man. The species is now collected commercially for the aquarium trade as it has been found to be particularly suitable for large enclosed environments, such as sealife centres or public aquariums. There are problems associated with the transport and health of these sharks and a number of aquariums have reported fatalities. Conservation bodies are against this trade in sharks. Ecology: Regularly seen in the eastern Mediterranean during late summer, particularly off the coast of Lebanon, Syria and southern Turkey where it can occur quite close inshore near vertical cliffs and deep reefs. Denser than water, it is known to swallow air at the surface to help its buoyancy.

SMOOTH HOUND

Mustelus mustelus

Growing to around 1.60m (5ft 4in), this small, smooth-skinned shark has large eyes and a long and slender body with a sharply pointed snout and five gills. The species has two large, almost equal-sized, dorsal fins and unlike the Spurdog, has an anal fin. Its main prey species are bony fish, squid and octopus, and small crustaceans. Ecology: The species likes bottom-living and tends to stay in deep water during the day and rises into shallow waters around the coastline at night to feed.

BLUE SHARK

Prionace glauca

This shark grows to 3m (10ft), has a slender body, wing-like pectoral fins, long snout and large eyes, and is blue in colour. At night the colour changes slightly to a greenish shade. It feeds on small fish and squid rounding up the schools and attacking fiercely. Largely under threat by man, it is caught by drift net and ‘sport’ anglers. Ecology: This is a pelagic shark, often working in small groups as it hunts around inshore shoals of fish. Blue Sharks are the widest ranging of all cartilaginous fish, being found in all tropical and temperate waters. Tagged individuals from the Canary Islands have been found in Cuba and individuals from the USA have been captured in Gibraltar, indicating that they use the equatorial currents in their migration patterns.

LESSER-SPOTTED DOGFISH

Scyliorhinus canicula

Although this is referred to as a ‘dogfish’ it is actually in the cat shark family and is perhaps the most common of all the species encountered in the region. Rarely over 1m (3ft 3in) in length, its body is rough to the touch and is covered in dark spots and blotches. Ecology: It is common in shallow waters and lays its eggs from May right through to September when it attaches its ‘mermaid’s purse’ egg case by four long flexible tendrils to various sea fans. Depending on the location and amount of plankton in the water, these egg cases gradually become covered in marine life, further protecting the delicate embryo inside.

NURSE HOUND

Scyliorhinus stellaris

Very similar to the Lesser-spotted Dogfish, this is a much larger species, growing to almost 2m (6ft 6in). A purely nocturnal feeder, it preys on octopus, molluscs, crustaceans and demersal fish. Ecology: This species is hunted for use in aquariums as it is sedentary of nature and requires little work to keep it happy!

ANGEL SHARK

Squatina squatina

Growing to around 1.80m (6ft), this is a nocturnal bottom-dweller, more like a large ray than a shark. Roughly diamond-shaped, it has large, fleshy pectoral fins and a rounded snout with a speckled body. Ecology: It is generally buried in sand and stalks fish in this way, lying in wait until fish pass close to the large mouth. It opens its mouth wide, whilst lunging upwards, drawing the hapless prey into its mouth. It is quite harmless to humans and generally fearless of divers.

SPURDOG

Squalus acanthias

Very similar in shape and appearance to the Smooth Hound, this small shark is distinguished by an obvious spur or spike directly attached and in front of the dorsal fin. The males reach over 1m (3ft 3in) in length, whilst the females are much smaller at 75cm (2ft 6in). Ecology: Fairly slow moving, it migrates from deeper waters into shallow estuaries during the summer months to have its young.