Sea hare in Fuerteventura

Sea hares are large marine slugs found in coastal waters around Fuerteventura. Despite their name, they are not slugs in the terrestrial sense, but soft-bodied marine molluscs related to sea snails.

They are often found in shallow rocky areas and seagrass beds, where they feed and move slowly across the seabed.

What they look like

Sea hares have soft, leathery bodies with fleshy extensions on their head called rhinophores. These are sensory organs used to detect chemicals in the water.

They often have a small internal shell and wing-like flaps along their body called parapodia, which help with breathing and sometimes movement.

Colouration varies, but species found in the Canary Islands are typically grey, brown or dark green with patterned markings.

Sea hare moving slowly across the seabed while searching for algae in coastal waters

Where they are found in Fuerteventura

Sea hares are commonly found in shallow coastal waters, particularly in rocky areas, sheltered bays and seagrass zones.

They are usually encountered by snorkellers rather than divers due to their preference for shallower environments.

Behaviour and defence

Although slow moving, sea hares have interesting defence mechanisms. When threatened, they can release a purple ink into the water to confuse predators.

They can also produce a sticky chemical called opaline, which helps deter attackers by interfering with their sensory systems.

These defences give them time to escape, even though their movement is slow.

Diet

Sea hares feed mainly on algae. As they consume algae, they can store some of its chemical compounds within their own tissues, which may help make them less appealing to predators.

Reproduction

Sea hares are hermaphrodites, meaning each individual has both male and female reproductive organs.

During breeding, they can form chains where multiple individuals are connected, with different roles in fertilisation along the chain.

They are capable of producing very large numbers of eggs, often laid in long gelatinous strands attached to rocks or vegetation.

 In Fuerteventura waters

Sea hares are a fascinating and unusual sight for snorkellers exploring shallow reef and rocky areas around the island. Their slow movement and unique appearance make them a standout species among coastal invertebrates.

Sea hares are part of the reef and coastal invertebrate community found in Fuerteventura’s shallow waters.

For more marine species found in the region, see the Marine Life in Fuerteventura guide.