European green crab
The European green crab is a small, usually greenish, crab species that is common in Icelandic waters. It is particularly common along the warmer south coast of Iceland, but has also recently been found in colder seas on the north coast.
It is now found all over the world except in the tropics. However, it was not always so because it is an invasive species. Before, it was only found along the coast of Europe. However, it has spread all over the world probably with ballast water.
The green crab is usually found on shallow seas, from a shoreline down to a few tens of meters depth. It can withstand high temperatures and fluctuations in salinity and can even survive dry for several days. It also has a very broad taste of food.
Probably that is why it has spread around the world, it always finds something it can eat and can tolerate in all kinds of environments. This is also why it is regarded as a pest, it can alter the new ecosystems. The green crab is not fished in Icelandic waters, it is considered too small. However, it is fished in Europe.