Freshwater fish of scotland

The European Eel is a catadromous species, in that it resides in fresh water and moves into salt water to spawn. It is found in the rivers of scotland and in lochs which drain into the sea. The Eel's spawning grounds are in the Sargasso Sea near Bermuda. After spawning, the fertilised eggs drift towards Europe, carried by the Gulf Stream. once the larvae approach coastal waters, they metamorphose into a transparent eel form know as a 'glass eel'. Once in fresh water they feed on fish and invertebrates and grow in size and become darker in colour. Although Eels have not been subject to extensive commercial fishing in Scotland, they are still threatened due to heavy exploitation elsewhere in Europe. Scottish Natural Heritage estimates European Eel populations have declined by 90% in the last two decades. less ↑

Shad are an anadromous species found primarily in the Solway Firth in southwestern Scotland. Shad spawn in rivers, and then the juveniles head out to sea to feed on crustaceans and small fish for several years before returning to the river to spawn. Shad used to be subject to commercial fisheries which significantly damaged their populations, however British law now prohibits fishing for them. Scottish Natural Heritage lists water quality deterioration as the main threat to this species at present. less ↑

The Atlantic Salmon is an anadromous species of salmon which is found in most of the river systems of Scotland. They spawn in rivers, then the young head out to sea to feed, before returning after at least one year to spawn again. Although little is known about their migration patterns, it is known that they are excellent navigators, with individual populations return to the exact same spawning grounds year after year. They spawn in late autumn and winter, after which a majority of the adults die, however a small number will make it back to the sea and return to spawn again. The Salmon's diet varies throughout its life cycle. The juveniles feed in fresh water on small invertebrates and small fish. The adults feed at sea on sand eels, squid, herring and shrimp. The Salmon is subject to extensive commercial fishery, however farmed salmon is becoming more prevalent and dependence on wild stocks is not as high. Salmon returning after one winter at sea (grilse) are not subject to protection, however larger salmon which have spent more than one winter at sea are protected under British law. less ↑

The Brown Trout is found in most rivers and lochs in Scotland. some populations reside permanently in fresh water while some are anadromous (sea trout). The Brown Trout feeds on insects, insect larvae, and as they get larger, smaller fish. Some populations are isolated in deep lochs and grow to much larger than average size by feeding on Arctic Char, these are known as Ferox Trout. The Brown trout spawns during the autumn and winter, from October through to January. All the variants spawn in rivers, regardless of whether they have been in salt water or not. Brown Trout are not subject to extensive commercial fishing, however they are fished for by recreational anglers as they are good to eat. They are not currently a threatened species. less ↑

River Lampreys are one of the most ancient species of fish found in Scotland. They live in salt water and come into rivers in the spring and autumn to spawn. While in coastal waters they feed by attaching themselves to larger fish with their sucker-like jaws and feeding on the blood of their host. The River Lamprey is threatened as the water quality of its spawning grounds is deteriorating. It is afforded some protection under EU law, and one of its sub-species, the purely fresh water Dwarf River Lamprey is protected in a site of special scientific interest in Scotland. less ↑

The Arctic Char, according to Scottish Natural Heritage, was the first fish to re-colonise fresh waters in Scotland after the last ice age. It is found in numerous deep, cold lochs across Scotland. It feeds on a varied diet, consisting of such foods as insects, salmon eggs and plankton. The Char spawns in the autumn, from September to November. Arctic Char in Scotland are not subject to commercial or subsistence fishing, they are caught by a small number of recreational anglers, but this is not thought to be a threat to their population. Scottish Natural Heritage lists climate change and lake acidification as the most prominent threats to the Arctic Char. It is a protected species in a number of lochs, and populations also occur in lochs which are protected for other reasons. less ↑

The Pike is found in both lochs and rivers, typically in murky or weedy waters as they are ambush predators, requiring a habitat with plenty of cover. Pike are very aggressive hunters whose diet consists primarily of smaller fish, but they are not fussy eaters and will also eat frogs, birds and small mammals, they can also be cannibalistic. Pike spawn in the spring, once the water temperature reaches approximately 50 degrees. Pike are abundant in Scotland and are not subject to commercial or subsistence fishing. They are a popular sport fish, but a majority of this fishing is catch-and-release. less ↑

Sparling are found in coastal areas of Scotland, they live in estuaries and spawn in fresh water. They feed on shrimps and small crustaceans while in salt water. These fish move into fresh water to spawn by using the spring tides between February and April, a majority die after spawning. Because the Sparling relies on good water quality in order to spawn, its population has declined due to pollution. many Scottish rivers have lost their Sparling populations due to water quality deterioration and/or overfishing. Scottish Natural Heritage says that the Sparling is a protected species at two sites of special scientific interest. less ↑

Coregonus lavaretus, known as the Powan in Scotland is one of the rarest Scottish freshwater fish. According to Scottish Natural Heritage, natural populations occur in only two lochs, Loch Lomond and Loch Eck. fish from these populations have been transplanted to other lochs in order to establish populations as part of a conservation effort. the Powan is under threat from the Ruffe, an invasive species which eats Powan eggs. the Powan is on the IUCN red list of threatened species and is a protected species under British law. less ↑

The Perch is a small-medium sized carnivorous fish found in rivers and lochs throughout Scotland. they have a large spiked dorsal fin for protection against larger predatory fish such as Pike, and they feed on smaller fish. They spawn during the spring, laying eggs in sheltered areas such as weeds and submerged branches. Perch are not fished commercially but are caught by recreational anglers. The IUCN lists the European Perch's conservation status as 'least concern'. less ↑