This is the crustacean in question.

Photo: Herald Scotland 25/09/14.

Although they were first discovered invading the River Thames during the 1930’s the problem with them being in the
River Clyde is that they prefer to eat larger fish eggs. So the salmon and trout populations are now under threat. The
situation is being monitored.

This is Coconut Crab.

Photo http://www.amazfacts.com

They are the largest living arthropod and have been largely eradicated from densely populated areas in the Pacific and
Indian Ocean. Now he is scary.