Sea trout can be found all around the British Isles and Ireland, but for guaranteed sea trout sport head for the west coast of either England, Scotland, Wales or Ireland as the runs of these fish are the most prolific in those areas.
They enter our freshwater river systems between April and September, swimming many miles upstream to breed. They will use lochs and loughs to further their journey to the cleanest, pure upland rivers.
The sea trout is, in fact, a migratory brown trout that spends a great deal of its time in the sea. They both share the Latin classification Salmo trutta.
In terms of their shape, sea trout are identical to brown trout, but when the sea trout nears freshwater upon its migration it has a silvery appearance. There are numerous spots along the flanks, down to a line that is level with the base of the pelvic fin.
The colour of the adult sea trout darkens as it journeys through freshwater – then it’s even harder to distinguish a sea trout from a brown trout – the only real way to tell the difference is to look at the spots. Brown trout have red spots, while sea trout have dark spots.
Sea trout only feed when they are in the sea. Here they eat crustaceans, shrimp, prawns and small fish. They are particularly fond of sandeels.
To catch a sea trout you have to antagonise it into taking a bait, by either using plugs, worms, prawns or flies.
Sea trout usually breed between October and the end of the year. They breed in shallow, gravelly, pure and well-oxygenated rivers well upstream from the sea.
The young sea trout go through the usual salmonid life cycle of egg, alevin, fry and parr. This can take up to two years.
Once the parr reaches adulthood it changes and takes on a silvery sheen, then migrates to the sea. At this stage the young sea trout are called smolts.
Some smolt spend only a few months at sea and return to freshwater, and the remainder return to breed the following year.
The salmon is by far the most prized of all British game fish. It is a powerful and enigmatic species that make for excellent eating.
Although salmon can be found in all rivers dotted all around the British Isles, they are quite rare in a lot of places. Salmon much prefer perfectly clean and pollution-free water systems in which they travel upstream to breed.
There are some noted English rivers that do have a run of salmon – but your best bet would be to head to Scotland, Ireland or even Wales as here the run of salmon is far more prolific.
The average weight of a salmon is around the 6-12lb mark, with the British record standing at a massive 64lb.
The salmon is trout-like in appearance with its long and lean shape, powerful and large tail, and small adipose fin just above the tail.
Salmon can be quite easily confused with the sea trout, but looking closely at the tail you’ll find the salmon’s is concave while the sea trout’s is almost square.
The tail root of the salmon – called the wrist of the tail – is quite slender compared to that of the sea trout. The salmon’s tail wrist is quite rigid, therefore the fish can be lifted clean out of the water by the tail once it has been despatched – you couldn’t do that with a sea trout!
The colour of a salmon changes quite massively throughout its life cycle… When the salmon leaves the sea to enter freshwater it will be steel-blue/grey across the back and have silvery flanks with asterisk-shaped spots along the back and upper flanks. The scales will be easily removable and the fish may well be covered in sea lice. These drop off the fish after only a few days.
The longer the fish remains in freshwater before spawning, the darker it becomes. Many salmon, at this stage, develop brown or red spots too and they all take on a grey-bronze colour. The males develop a pronounced kype.
Salmon which have spawned will be much thinner than their un-spawned counterparts. These salmon, that are trying desperately to return to the sea to feed, are known as kelts. These fish MUST be returned to the water unharmed.
Salmon do not feed upon entering freshwater, but at sea they will feast upon crustaceans, small fish and prawns – their favoured food.
To catch a salmon requires a lot of skill and to present a bait or a lure in the right place at the right time – triggering the salmon’s instinct to snap at the bait and take it.
The best baits to catch a salmon are worms, shrimps, prawns and, of course, fly tackle and flies.
Salmon breed between October and January in the extremely shallow, clean and clear reaches of upland rivers.
The females dig out a depression in the river or stream bed – called a bed – and deposit their batch of large orange eggs. The males, who have found long and hard for the prime spots, using their kypes as weapons, immediately fertilise the eggs. The females then cover the eggs by thrashing the gravel with their tails.
After some three or four months the eggs hatch. These alevins are equipped with their own yolk sac to provide enough nourishment to continue growing into the next stage of the life cycle, known as parr.
Parr are 3-5 inches long. They gather in shoals for protection. They continue feeding on whatever insect life they can locate until they reach around 8 inches.
At this stage the parr lose their brown-grey colouration across the backs and blue spots along the flanks and take on a silver colouration.
These fish begin the arduous journey downstream to enjoy one, two or even three years feasting on the plentiful supply of prawns, shrimps and crustaceans in the sea. When they undertake this migration salmon are called smolt.
Young salmon of one year old that return to freshwater to breed are known as grilse.
Fresh Run Salmon
Cock in breeding dress
Hen in Breeding Dress
These gloriously coloured fish are extremely common across Britain due to their ability to adapt to Stillwater. This makes them the obvious choice species of trout to grow on within man-made lakes are reservoirs across the country.
The average size of a rainbow trout in the British Isles will be around the 1-4lb mark, but they can grown up to 30lb.
There’s no mistaking the rainbow trout. It has the classic ‘trout shape’ in that it’s sleek, has a pronounced dorsal fin and substantial concave tail fin.
The head of the rainbow trout is a lot more rounded than that of the brown trout, particularly around the snout.
The colours across the trout’s back and flanks make identification quite easy. The back has an olive sheen that blends into its silvery flanks. Running from the head right to the tail is a fantastic red band – almost holographic. Then there are a multitude of tiny spots - hundreds of them – dotted across the back, flanks, fins and tail. There are no spots on the underside of the rainbow trout.
Some rainbow trout living in deep and crystal clear reservoirs may not have the red band running along the flank. Instead they will be pure silver, overlaid with hundreds of dots.
Insects are a trout’s favourite food, no matter at what stage the insect life cycle may be, it is not safe when there are trout around!
They are aggressive feeders too - they prey on small fish as well as insect life and crustaceans.
To catch a trout is relatively easy as they will attack almost anything if they are hungry. Small spinners, spoons and plugs take some beating, as do worms and maggots, but the ‘accepted method’ is to fly fish for them.
The choice of fly, and associated lines, is not straightforward as you need to assess the depth at which the trout may be feeding and present your fly to suit.
The natural breeding of the rainbow trout within the British Isles is quite rare – it only occurs in very few river systems as the conditions have to be perfect for the eggs to develop and hatch.
The fish prepare to breed between January and April. The males darken (often known at this time as black fish) and develop a pronounced hook on the lower jaw together with a vivid orange mark on the gills, extending down the flanks.
The vast majority of rainbow trout in the country are farm reared and stocked into mostly. Some keepers of rivers introduce rainbow trout too.
There can be no mistaking the grayling, otherwise known as ‘the lady of the stream’. It can be identified by its smell as well as its looks!
They prefer to live in swift-flowing streams running over gravel or sand, but it will live happily in large rivers too. It is fairly widespread in Scotland and north England, also within the many chalk streams of southern England. Grayling are really widespread in Welsh rivers.
Although the grayling is widespread in Europe, there are none in Ireland.
The average weight of a grayling is around the 10oz mark, but given ideal circumstances and a plentiful food supply they will reach weights in excess of 3lb 8oz.
There are two ways to identify a grayling – by looking at it, and by smelling it! Grayling smell quite strongly of the herb thyme, hence the Latin description.
They are quite lean and slender fish having an extremely large dorsal fin for their overall size. The scales are very small and have dark edges.
The back of the grayling is either dark grey or a pewter colour, which merges to off white/silver flanks. The underside is white.
Grayling feed upon crustaceans, insect larvae, small fish and molluscs. They also adore fish eggs which, in the main are yellow, and that’s why one of the best baits you can use to catch a grayling is a grain of sweetcorn.
Other great baits to use to tempt a grayling are red or white maggots and fly tackle – the most ‘accepted’ technique.
Grayling breed during the early weeks of spring where they seek out gravelly bottoms. They lay a multitude of eggs which take around 20-25 days to hatch.
The brown trout is a sleek, lean fish that is very powerful indeed, having a thick and muscular tail. They are indigenous to Europe and survive very well in the British Isles. In fact, no other freshwater fish is as widespread in this country as the brown trout. It can be found in the tiniest chalk streams of the south coast to the peaty tarns of the Scottish highlands. They are particularly prevalent in the vast loughs and lochs of Ireland and Scotland. The brown trout a real success story.
In running water they prefer to take up residence tight to a feature such as bridge supports or rocks, or even in the shallows where the water is heavily rippled to help disguise the fish.
In stillwater the brown trout will lay up deeper than that of the rainbow trout. And in some deep Scottish waters there can be found older brown trout that have turned predatory and often cannibalistic – these are known as ferox trout.
Brown trout are smaller than the rainbow trout, with the average being between 1-2lb and a monster being 20lb.
Ferox trout - pic supplied by Ceri Jones
The brown trout has all the classical salmonid features – an adipose fin set upon the root of the tail, a large dorsal fin, a thick a muscular tail and a sleek body shape. The tail is square or just slightly concave.
As the male brown trout grows, its lower jaw becomes to curve upwards slightly. During the spawning season the jaw will be even further pronounced, this is called a kype.
The colouration of the brown tout varies immensely. It can even vary between individual fish living in exactly the same circumstances in the same fishery.
Those fish that inhabit crystal clear chalk streams will tend to have a brown or even a gold back, slightly paler sides and a yellow, almost buttery, underside. They will be adorned with spectacular spots in either black, red or brown – sometimes all three colours – that are rung in white.
Stillwater brown trout living in reservoirs, vast rivers or man-made waters may well have silver flanks together with star-like shaped spots.
Like the rainbow trout, brown trout are very aggressive. They will feast upon crustaceans and insects that are at any stage of their life cycle. They will eat small fish too, including their own fry (called parr).
To catch a brown trout can be extremely easy if the fish are involved in a feeding frenzy. At those times you’ll easily catch them on spinners, small plugs and small spoons. Other baits that are renown to tempt brown trout are maggots and worms. But, often is the case, these baits are frowned upon and the only ‘true’ way to catch a brown trout is with fly tackle.
Here you’ll have to pick your fly lines and flies with a high degree of knowledge as you will have to present the right fly at the right depth to trick your quarry into taking it.
Brown trout breed in the depths of winter in highly oxygenated and shallow streams, over a bed of gravel. The female lays her eggs onto the gravel and immediately the male will fertilise them.
The life cycle of a brown trout is the same as all salmonid species: first the egg, then the alevin, then fry, then parr and finally the adult.
The brook trout is not native to the British Isles – it originated from America, where it is often called the brook charr. It thrives in very clean and pure rivers and streams where it can attain weights of over 10lb, but in this country you can expect to encounter 1-2lb fish. A 5lb brook trout is a monster for the British Isles.
They are quiet few and far between in this country – only rivers and stillwaters that have been stocked hold them.
They are very close in shape to the brown trout. They have a tiny adipose fin, square tail, large dorsal fin and the mature males have and upturned lower jaw.
The main means to tell the difference between a brook trout and a brown trout is to take a look at the fins. The pectoral, anal and pelvic fins are edged in white.
They have blotches around the back and flanks. These are a very pale pink or cream, surrounded by grey. The underside of the brook trout is white or silver.
Insects and crustaceans are the staple diet of the brook trout, but they will also take small fish if the opportunity arises.
As these fish are stocked into waterways and lakes, there is a high chance that they can only be caught using the owner’s rules, and that will be by fly. Your choice of line and fly will have to be made once you visit the venue and understand at which depth the fish are feeding.