There are five main species which make up the group commonly known as 'game fish' in Scotland...
There are five main species which make up the group commonly known as 'game fish' in Scotland. These are the Atlantic salmon (Salmo salar); the brown trout (Salmo trutta) and its migratory sub-type the sea trout (also Salmo trutta); the arctic charr (Salvelinus alpines), and the non-native, but widely distributed, rainbow trout (Oncorhynchus mykiss). Placing wild animals into categories is always fraught with difficulty; attributing certain fish to the category of 'game species' is no exception. Many anglers hold the opinion that the grayling (Thymallus thymallus) should be included with the other game fish, while the increasing hybridisation of rainbow trout, North American brook trout and charr species has brought a plethora of interesting and exotic species to Scotland’s stocked trout waters.
Native brown trout, or as they are affectionately known in Scotland - 'broonies' – are found widely throughout running and still water. They need relatively few life requirements: cool, clean, oxygenated water; suitable food; a place to hide when predators threaten; and favourable conditions to reproduce. If these elements are present, then a population of trout is likely to be present. Scotland’s climate provides ample rainfall to keep most streams supplied with running water and its temperate climate does not suffer from extreme temperatures. Most of the lochs and rivers are free from major pollution, so food is relatively abundant, which enables the brown trout population to thrive.
Brown trout spawn primarily in running water in the closing months of the year. Spawning may by close to the area where they normally live, or may involve significant migration out of Stillwater into headstreams, or further upstream in some river instances. The fry hatch in late winter to early spring when winter releases its grip and the availability of foodstuff increases. The tiny fry grow over two to three years into 'parr', often in close proximity to their salmon parr cousins. The mature brown trout may live for many years and growth reflects, the abundance of feeding and the amount of energy output, which it needs to make in its adopted territory.
In rivers, brown trout take up 'lies' where they wait for food to be brought to them by the current. Often, you will see the same fish in the same 'lie' on many visits to a pool – they become 'auld freends'. The logical cause of this behaviour is that they adopt the optimum position to gain the best food supply, combined with a suitable deep or sheltered place to avoid predators and a comfortable flow of oxygenated water. There may be a distinct 'pecking order' in these trout lies, with the biggest trout taking on behind – a case of 'the survival of the fittest'. Catch one brown trout from a certain lie and there is every likelihood that others will soon drop into the vacant place.
In lochs, predictably, trout tend to be found where the greatest quantity of food items are concentrated. In general, this occurs where sunlight fuels the life cycles of plants and the insects that feed upon them. Most of the trout’s diet is composed of aquatic species which, in turn, live where their food items proliferate. Sunlight, generally, does not penetrate the water of Scottish lochs much deeper than ten to fifteen feet in sufficient quality to sustain plant growth. At this depth, aquatic life tends to become less plentiful. Consequently, most trout are found in the marginal, shallower areas of lochs. However, this is a huge generalisation and trout often travel over deep water – so this exception exists to prove the rule.
The temperature of the water in lochs creates distinct warm and cold water layers – especially when winds are light. Over the winter months, layers tend to form at depth due to the greater density of cold water, with uppermost (less dense) layers comparatively warm. Winds can push this uppermost layer of warm water up against the lee (downwind) shore but this in turn tilts the whole layering system of the loch exposing the under-layer of cold water at the upwind shore. Feeding is more likely to be concentrated at the warmer end of the loch. However, even this 'rule' is broken by other effects. During very warm spells, the water heats up at the surface. Oxygen dissolves in water directly from the air but the warmer the water, the lower the oxygen content – so fish may have to swim deeper to find more comfortable conditions.
It is not uncommon for the wind to blow terrestrial insects like daddy-long-legs or heather flies, onto the water at the upwind shore where trout readily accept this concentration of food. At the other extreme, hatching aquatic insects may be blown into the islands also tend to affect the concentration of food items, so it is not always straightforward to assess where most feeding is occurring. The species of insect which the trout eat, influences where and how they feed. It can be a very complex affair. Suffice it to say that there are logical systems at play, but feeding activities may be concentrated in different ways at different times. The trick is to be lucky, especially if you find difficulties in interpreting the complexities!
The range of habitat occupied by trout populations is diverse. They are found in the lochs and burns of the Highlands, often at considerable altitude, and are also present in lowland lochs and partly-saline estuaries. In northern and Highland waters, adult trout tend to by small due to prolonged winter cold and the short season when food is abundant. An adult brown trout in this type of water may reach around 20 centimetres after several years; whereas a trout of similar age in a richer lowland loch may be several times this size. In some lochs there are large trout, known as 'ferox', which have adopted a part-cannibalistic form of feeding and are the quarry of a special type of game fishing.
One of the attractions of wild Scottish trout is their range of colour and markings. In dark parts of rivers, usually gorges with deep overhung pools, they tend to adopt correspondingly dark brown/bronze-coloured camouflage; whereas in lochs, with bright sandy bottoms, the trout are butter-yellow with bright vermillion-red spots. In some waters they have shiny silver-lemon colouring and in others they have a wonderful golden sheen, which is highly attractive. The patterns of their markings also varies with some being very heavily-spotted, while others have lighter speckling or almost none at all.
Until recently, it was firmly believed that sea trout and river brown trout were separate species, but this has been disproved. Some brown trout offspring adopt migratory lifestyles - in other words, they become sea trout - while some of the offspring of sea trout may live all their days in the river as brown trout. Late twentieth-century technologies, such as DNA polymerase chain reaction and genetic probing, have enabled these fascinating findings to surface. Exactly what turns one fish into a migratory form, but does not influence its brothers, has yet to be determined. It may be the result of nature's heterogeneity creating the widest range of survival characteristics. For the wider the diversity of life traits that a species adopts, the higher its chances of overall survival - and trout have swum in Scottish waters for a very long time.
Most trout eat a varied diet. In lochs, the largest part of their diet is composed of aquatic insects, paticularly 'midges' (belonging to the order Chironomidae). The chironomids are also known coloquially as 'buzzers' due to their high pitched whine when they buzz close to, or into, your ear. Fortunately for anglers, the midges differ from their landward cousins because they do not bite humans. Anyone who has suffered the onslaught of the Scottish biting midge (Culcoides impunctatus) will know only too well their voracious appetite for human blood - although curiously, it is only the female that bites.
Trout eat most food items; it is unusual for a post-mortem examination to find only single species present in their alimentary canal. This opportunistic feeding is a result of the wide range of locally-available food, which includes: daphnia, shrimps and other small crustaceans; molluscs like freshwater snails and bivalve shells; the truly aquatic insects of the Chironomid species; the 'upwing', day-flies (Ephemeroptera); the 'sedge' and caddis' flies (Trichoptera); the 'stone flies' (Plecoptera); water-boatmen (Corixa) and the damselflies and dragonflies (Odonata). Added to this is the colossal variety of terrestrial insects like house flies and bluebottles (mostly of the order Diptera); bees, ants and wasps (Hymenoptera); butterflies and moths (Lepidoptera); beetles (Coleoptera); a few spiders (Arachnida); a grasshopper or two (Orthoptera); several small fish, an unfortunate tadpole, worms of various types and sizes and even the odd cigarette end!
Arctic charr are natural relics from the retreat of the last Ice Age. They are found in Scotland's deeper lochs, often in large shoals, although they tend not to be fished in the context of sport. In some countries around the Atlantic fringe, charr migrate into the sea and run the rivers to spawn. In Scotland they are 'land-locked' in the lochs. From time to time, they may be caught in rivers flowing out of the lochs where they normally live. They have beautiful colours and markings, particularly around spawning time, when they are deep bluegrey along the back with speckled bright orange-red flanks. The lower part of the pectoral, pelvic and anal fins and tail are sharply-edged with white. It is not unusual to catch charr when fly-fishing for trout in these lochs - this adds an extra dimension to a day afloat. They also make fine eating, especially if smoked. Ferox trout feed heavily on charr populations and some lochs, which have fish farm cages in them, hold larger charr that thrive on uneaten food falling from the cages.
It is probably the Atlantic salmon that is most - closely identified with Scotland's fishing heritage. Here is a rich vein of Scottish outdoor culture, for there is a wealth of fact and fiction attached to this mystical and beautiful fish. We know a lot more about the salmon than we did previously - a great deal of research has been undertaken recently to understand its life cycle and biology - but it still remains enigmatic in many ways.
Salmon have been proven to consume nothing during the journey upstream, begging the question of why they take an artificial fly or fishing lure into their mouths. Many believe that they are curious about the unusual object that comes into view beside them and are trying to find out what it is. They sometimes seem to become irritated by it and chase after it, grabbing it aggressively. This is particularly true of male fish, which become very territorial and protective of their locality as they approach spawning maturity. Whatever the reason, salmon anglers the world over accept with gratitude that the mighty fish may sometimes be persuaded to accept their lure.
Standing at a pool-side watching salmon head upstream is utterly fascinating. Their great paddle tails are so powerful against the weight of the current. One decent thrust sends the fish off at high speed or careering out of the water in a spectacular, glittering leap. They may lie, finning quietly in the current, as though in a torpor, seemingly disregarding everything around them; then something breaks their reverie and they seem to startle into alertness; their whole demeanour changes from being inert into a state of quivering excitement. They are truly magnificent fish and a wonderful sporting quarry. Like the trout and charr, the salmon has swum in Scotland's rivers far longer than the riverbanks have been trodden by anglers. The Scottish salmon is so precious, a fascinating natural asset, and worth careful preservation and conservation.
This graceful fish is found in many of the Lowland rivers of Scotland. It is not a fish of rocky west coast spate rivers, where cascades and wild thrashing torrents abound, it is found in more sedate surroundings. The larger rivers of eastern Scotland have good grayling populations especially the Tay, Earn, Tummel, Isla and Tweed. Nevertheless, they are distributed widely wherever quieter streams are found. Affectionately known as the 'Lady of the Stream', the grayling offers fine angling opportunities for those who wish to fly-fish or use fine bait fishing techniques - especially when the trout season has closed.
The grayling occupies a similar ecological niche to river trout, therefore, although the trout's range is wider, grayling are often caught when fishing for trout. Trout and grayling co-exist without major difficulty, diversifying Scotland's game angling potential. The influence of eastern European fly-fishing techniques has impacted on grayling fishing in recent years, with the weighted and woven nymph patterns emanating from the former Czech Republic proving to be highly successful. This is due to the grayling's main feeding trait of taking the nymphs of aquatic flies and other species near the bottom. A pleasant alternative to fly-fishing is to trot a small worm, either using a small float or allowing the bait to run free, through likely pools and glides. Red and yellow-striped 'brandling' worms seem to work best. Grayling are shoal fish. Catch one, and you should be able to catch others. However, they are easily spooked and require to be fished for with care and skill - a demanding, attractive and worthy quarry.
THE RAINBOW TROUT
Originally introduced from North America, the now ubiquitous 'rainbow' is wholly established in Scottish fishing. In a way, it simply had to be, for the increased pressure of angling on brown trout would have jeopardised native stocks of brownies. Many waters could not have continued as fisheries had it not been for the availability and lower cost of stocking with fast-growing 'bows'. Initially, rainbow trout in Scotland were second -class citizens due to their poor quality. Now however, fisheries stock with high-quality fish, fully worthy as an angling quarry. Consequently, a shift in the methods of Scottish trout fishing has occurred, fuelled by the powerful rainbow. Methods of catching rainbows differ from traditional methods of brown trout fly-fishing; a new generation of anglers has grown up who fish almost exclusively for 'bows'.
Rainbow trout have not naturalised after initial stocking in the way that they have done in other parts of the world. The reason for this is not clear, although small rainbow trout have appeared from time to time in Scottish rivers as though they had come from natural spawning. Similarly, rainbows that have migrated to sea - much in the same way as sea trout - have appeared in some of our rivers and these migratory fish are very like their North American counterparts, the legendary Steelhead Trout.
Rainbows are voracious feeding machines. They 'hoover-up' anything that is edible, and grow at prodigious rates under optimal conditions. This constant state of hunger makes them highly susceptible to the angler's fly-much more so than their cautious native cousin, the brownie. A well-conditioned rainbow is a sleek, powerful fish that fights strongly when hooked. Much depends on how well rainbows are reared. If they are kept in over-close proximity to each other, they damage their fins and tail. If they are overfed and under-exercised, they grow fat and deep. The best rainbow is torpedo shaped, fully-finned and brightly coloured. They are beautiful trout with iridescent purple-pink hues (hence their 'rainbow' description) along their flanks, are lightly speckled over the body, but heavily-speckled on tails and fins, and have bright -silver scales, which are sometimes matched by the rays of their fins that take on a silver colouration.
When you hook a decent 'bow' you soon know about it. They pull strongly and tend to leap out of the water more than brownies, adding to the excitement. They are shorter-lived than brown trout, often reaching only five or six years. Brownies may reach several times this age, but rainbows live life to the full and provide excellent sport. In the history of Scottish fishing, nothing has influenced and changed the course of this pastime more than the introduction of the rainbow trout. Love them - as many anglers do - or hate them, they are here to stay and form a huge part of our sport.