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The Seashore

Sea Hare (Aplysia punctata)

Sea Hare (Aplysia punctata)

Like a sea slug (actually a separate order of the Opisthobranchs). There is no obvious shell on this mollusc but it is internal and can be easily felt through the skin. It is covered by the mantle. When fully open it can be 20 cm long and with wing-like extensions, called parapodia, to the side of the body. Two pairs of large tentacles on the head. The colour is a purple-brown.

This slug-like animal is one of the largest to be met on the seashore. When disturbed they release a purple dye which can be prolific (see below). It uses the wing-like parapodia to swim through the water and quickly disperses itself. They are hermaphrodites, having both male and female organs but still need to mate with another to cross-fertilise. They collect, during the spawning period, into quite large numbers in rock pools. In this way they begin to link together in a chain. Each will inject sperm into the one in front and pick up from the one behind! The eggs are laid in pink strings amongst the seaweeds. The eggs hatch into a larval form called a veliger and this lives in the plankton until it develops into an adult.

Sea Hare (Aplysia punctata)

Sea Hare having released a purple dye to repel would-be predators.

The Sea Hare is widely distributed along the Atlantic and Channel coasts including the Mediterranean. It normally only comes on to the beach when it spawns in early summer. It enters rock pools of the middle and lower rocky seashore where a number can be found together.

See also Sea Slugs

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