Leach's Spider Crab

Leach's spider crab or Inachus phalangium is a small spider crab which is found all around the coasts of Great Britain and Ireland.

It is most commonly seen in depth between 5-11m but some sightings have been recorded as deep as 50m.

The crab is up to 2cm long and has slim legs. The front claws are usually held below the body and are larger in males.

This spider crab camouflages itself by using bits of sponge and algae to ensure it blends in with its surroundings

It can be difficult to distinguish from the Scorpion spider crab, Inachus dorsettensis, however the Scorpion spider crab has bight pink or violet segments behind its claws and spines along its body.

The Leach's spider crab is commonly found living with Snakelocks anenome but this does not appear to be the case in Strangford Lough. They are most commonly seen in Ringhaddy Sound but more recently we have spotted them on the wreck of MY Alastor.

The numbers of the species have been relatively unknown in Strangford Lough. Project Baseline is therefore notifying the Centre for Environmental Data and recording (CEDaR) on all the sightings of this species. It is not currently believed to be at risk but could be affected by human activity such as fishing that relies on dredging such as scallop fishing.