Crustaceans are in the phylum arthropoda along with insects and chelicerates (spiders and allies). Insects dominate on land but not a single species can be found below the ocean surface. A few chelicerate species can be found there, for example sea spiders. However, crustaceans dominate over most other animals groups in the ocean.

Crustaceans are the most species rich group of marine animals and can be found in all marine habitats. In the pelagic zone one group of crustaceans is perhaps more abundant than all other animal groups combined. These are the tiny copepods, they form a very important link between phytoplankton, which they eat, and larger animals. Several other planktonic crustaceans can also be abundant, particularly larger krill and smaller cladocerans.

Benthic crustaceans are of various sizes. Many, such as amphipods and isopods, are insect-sized and are, as insects are on land, important for the benthic ecosystem as scavengers and grazers. One group of crustaceans, the barnacles, is sessile; they are found in abundance on the seashore, but also occur deeper.

Shrimps are intermediate in size. Many species of shrimp can be found around Iceland, but only one is abundant enough to sustain catches; northern shrimp (Pandalus borealis), commonly referred to as just “shrimp” in Iceland.

The largest are the true crabs and lobsters. Several species of crab can be found in Icelandic waters, but no species is abundant enough to sustain commercial catches. However, only one species of lobster lives in Icelandic waters, Nephrops lobster, which is an important commercial species. It is only found in the warmer waters of the southern part of Iceland.

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Krabbafló (mynd SHA) Krabbafló (mynd SHA)

Þanglús (Mynd: Erlendur Bogason) Þanglús (Mynd: Erlendur Bogason)

Litli kampalampi (mynd Erlendur Bogason) Litli kampalampi (mynd Erlendur Bogason)