Brown trout are the indigenous species of trout throughout Britain and large parts of northern Europe. They grow large, well in excess of 20 lb (9.01 kg), but the average is nearer the 1 lb (0.45 kg) mark. They are extremely variable in coloration, which is largely dictated by the individual fish’s habitat. Where the water is dark or peat-stained the fish themselves are often very dark with many large black spots. Conversely, where the trout are living over a light sandy bottom they are much lighter with either pale or silver flanks and much smaller and less profuse spots.
Most brown trout have a brownish- colored back and pale, liberally spotted flanks, Normally there are no spots on the tail, which is a useful guide to distinguishing them from rainbow trout. Usually, these flank spots are large and black, but occasionally, in trout living in small brooks, they can be mixed with a few red ones. Some populations also have bright-yellow bellies, giving -them an extremely colorful appearance, yet others the spots are almost absent, the flanks being bright silver and making the trout look very similar to its sea-run form, the sea trout.
Habitat and Location
Brown trout can be caught on a wide range of methods including bait, spinner and fly although in the UK, due mainly to fishery rules, most are taken on the latter. Although the brown trout is the natural species in the UK and Europe, fishing pressure and fluctuating water conditions mean that many are actually stocked in the same way as rainbow trout. However, due to the fact that the brown trout is less tolerant of high water temperatures and is slower growing than the rainbow, it is more expensive to produce and, as a result, stocked far less extensively. However, this still means that brown trout can be caught in many waters that would not normally contain them, most noticeably small put-and-take fisheries and large lowland reservoirs.
Some of the smaller waters, most famously Dever Springs in Hampshire and Felindre in South Wales, stock farmed brown trout of unnaturally huge proportions, Here fish of 10 lb (4.54 kg) or more are caught regularly and the cultivated record now stands at over 26 lb (l I .8 kg). On reservoirs Where the brown trout is stocked but must attain the bulk of its weight in the reservoir, a specimen brown trout would be classed as anything over 5 lb (227 kg).
Even here there are very big grown-on fish) and each year venues such as Rutland Water and Grafharn Water produce brown trout into double figures. In a river, a trout over 4 lb (l .01 kg) is a prize specimen. Most small lakes and reservoirs have to be stocked, but even some rivers which already contain indigenous populations of brown trout have their numbers supplemented with stockfish. While this makes the fishing initially better, it does raise the issue, should stock and wild fish interbreed, leading to the destruction of the wild fish’s genetic integrity? To counteract this trend some enlightened fishery owners are now looking to habitat conservation and catch-and-release fishing to maintain viable, natural populations. Almost all trout are caught on a fly, although spinning with minnows and fishing with a worm in small burns in Scotland and Wales is a good method for the young.
The most sophisticated fishing is with a dry fly or nymph in a clear chalk stream, although wet flies are the normal method in stillwaters. for fish such as perch and, especially, char which inhabit the deep water in these otherwise nutrient-poor lakes. This diet allows the ferox to attain weights of 10-15 lb (4.54-6.8 kg) with specimens up to 20 lb (9.07 kg) occasionally taken on rod and line.
Behavior and Feeding Habits
Brown trout are highly territorial, particularly in rivers. Once a fish has established a feeding position it will defend it jealously, driving off other trout that come too close. Here the trout is in an ideal position to pick off the adults and nymphs of aquatic insects such as upwings, stoneflies and caddisflies, along with small crustaceans, as they drift downstream with the current. Even on rivers brown trout have a taste for small fish and are not averse to taking bullheads and minnows, particularly early in the year when other forms of food are scarce.
Brown trout are found anywhere from tiny mountain streams to larger rain-fed rivers and rich) chalk streams. The size that the trout ultimately reach depends greatly on the available food supply and chalk-stream, loch and lough trout, with a plentiful diet of aquatic insects and crustaceans, are generally bigger than those found on rain-fed rivers and streams where natural insects are less abundant.