Intertidal and continental shelf habitats

Some habitats are exposed to extreme conditions, so are relatively bare or support a limited number of specialist species. Other habitats are highly productive and biodiverse, supporting many species of fish, seaweed and invertebrate species, including many of commercial interest. In the intertidal, seaweed, mussels and other molluscs, as well as worms for bait may be collected by people. When the tide is high, some fish species will forage over these intertidal habitats, meaning these habitats indirectly support other species, including those that are fished commercially.  Trawl and dredge fisheries mostly target species that live within, on or over subtidal sediment habitats, including prawns (langoustine/'scampi’), scallops and demersal finfish. Some habitat-forming species associated with sandy and mixed substrates, such as maerl, flame shell and seagrass beds, can provide a particularly important function as a refuge for juvenile or spawning stages of a variety of species of commercial interest (e.g. scallops). Typically habitats that are structurally complex in either the rock configuration, or as a result of the associated colonising species (whether above or below the sediment surface) offer good potential for supporting fish and shellfish populations. Ongoing physical disturbance of these habitats often reduces the complexity of habitats and undermines the sustainability of associated fish and shellfish stocks. Ensuring the health of these habitats and communities is maintained and keeping any exploitation within sustainable limits, will support the viability of these resources.