Threats to sea lochs
The remoteness of Scotland’s west coast and islands has protected the sea lochs from most of the major threats affecting coastal inlets elsewhere in Britain, particularly industrial and domestic development and its associated habitat destruction and pollution, and runoff from industry and intensive agriculture further inland. Traditionally settlements around sea lochs are small and so are the inputs of effluents from sewage and crofting activities.
Water flow is an important factor affecting sea loch wildlife and habitats. The construction of bridges and partial infilling of loch sides to support new roads involves some habitat loss but new surfaces soon recolonise are providing the water flow through the loch is not restricted.
Some aspects of fish farming can create environmental problems in sea lochs. Some of these problems have been addressed as the industry develops, such as not siting fish farms in poorly flushed areas with little current. In these conditions the seabed beneath salmon cages can become fouled with uneaten fish food and fish droppings causing the seabed to become anoxic, killing marine life immediately below the cage.
Other concerns are the continued use of pesticides to control infestations of sea lice and antibiotics to control fish diseases, these chemicals are also harmful to other marine life. There have been improvements in recent years through management agreements between different fish farmers which has helped to control disease and hence reduce the need for chemical treatments. However effective disease controls which do not damage other marine life are still needed.
There is also concern over the use of certain fishing methods in the sea
lochs. Trawling and dredging of the seabed can damage marine communities
of both commercial and conservation value as sea lochs are important settlement
and nursery areas for young fish and shellfish. The year-round closure of
some sea lochs to trawling and dredging would allow stocks to recover and
allow greater use of the sea lochs for less damaging static fisheries such
as potting and for shellfish culture.