The Open Sea

A large number of species occur in the open sea around Northern Ireland. Most of these are microscopic algae (phytoplankton) and grazing animals (zooplankton). In addition, many of the benthic species have free-floating stages.

There are over 100 species of fish which occur in our coastal waters. These include several commercial species and the second largest fish in the world, the basking shark (.PDF 188Kb), a priority species which occurs throughout the area and is sometimes found in large shoals associated with the oceanic front between the County Down coast and the Isle of Man. Little is known about the biology of this species around our coast.

A number of mammals occur in Northern Ireland waters. These include both common and grey seals which are both widespread around our coasts and six species of cetacean (whales, dolphins and porpoises) which either inhabit the area or visit it annually. The harbour porpoise and the bottlenose dolphin are both UK priority species.

The open sea also provides feeding areas for many internationally important seabird populations such as terns in Strangford Lough, Carlingford Lough and Larne Lough (which include the roseate tern, a UK priority species) and auks and kittiwakes on Rathlin Island.
jncc seabirds
Many marine habitats around our coasts have deteriorated because of fishing practices, pollution and development.