Brown trout and sea trout are medium to large sized game fish found throughout the world. Brown trout and sea trout are both beautiful fish.
Both brown trout and sea trout are targeted by anglers as a prized fighting fish and also as an eating fish as both are highly appreciated for their taste.
Brown trout (scientific name Salmo trutta) are a freshwater game fish of the Salmonidae family. This family is popular with game fisherman as it also includes salmon, rainbow trout and grayling. There are several common names given to brown trout across the British Isles where this species is native and popular.
They are called sewin (in Wales), mort (in North West England), peal (in the West Country), white trout (in Ireland) and finnock (in Scotland).
Sea trout are in fact brown trout (and therefore have the same scientific name) which have migrated out to sea before returning to freshwater to spawn. Opinion was divided throughout history as to whether the species were indeed separate or the same, with the different schools of thought debating well into the 20th century.
This issue has been put to bed and it is now established that they are the same species. Sea trout have the same common names which are given to brown trout.
Brown trout are generally easy to prepare, as after gutting and cleaning they do not require to be scaled unless it is a large specimen. There are many delicious recipes for brown trout and some historical recipes include frying in butter and nuts or simply grilling.
Brown trout and sea trout are both considered to be very healthy due to their natural oils. Sea trout are seen as a delicacy and are similar to salmon in taste. Many of the techniques used to cook or cure salmon such as cold smoking can equally be applied to sea trout.
Izaak Walton in his renowned The Compleat Angler of 1653 was full of admiration for “the trout”, he claimed as follows:
“The Trout is a fish highly valued, both in this and foreign nations. He may be justly said, as the old poet said of wine, and we English say of venison, to be a generous fish: a fish that is so like the buck, that he also has his seasons; for it is observed, that he comes in and goes out of season with the stag and buck. Gesner says, his name of a German offspring; and he says he is a fish that feeds cleanly and purely, in the swiftest streams, and on the hardest gravel; and that he may justly contend with all fresh water fish, as the mullet may with all sea fish, for precedency and daintiness of taste; and that being in the right season, the most dainty palates have allowed precedency to him”.
High praise indeed which gives some clues as to what will be written below.
Distribution and Habitat
Brown trout are an extremely popular fish both for food and angling and have been introduced across the world, far outside of their native range.
Brown trout are native to Europe and parts of Asia. In their native habitat, they can be found as far north as Russia and Norway, as far east as Afghanistan and Pakistan, as far south as Morocco and as far West as the UK and Iceland.
Brown trout have been extensively introduced to other areas which suit their preferred environment and have established wild and self-sustaining populations in many countries.
Brown trout were introduced to Australia over 150 years ago from Cornwall to Melbourne. They were also introduced to South Africa, Kenya, India, Nepal, Canada and the USA in the 1800s.
They can now be found as far afield as North and South America, Asia, Australasia, South and East Africa.
Brown trout require a good supply of running water which is well oxygenated. They generally prefer colder waters and within the waters they will stay close to some form of protection such as overhanging roots or tree branches.
They are known to inhabit rivers, streams, lochs, lakes and lakes. If they are found in lakes they will generally live in the deep water where there is a current which circulates. Sea trout will live in brackish areas or in the sea itself.
Brown trout are a medium to large sized fish. Brown trout are, perhaps not surprisingly, a dark brown colour on their backs. Their flanks are more golden or silver brown in colour and their bellies are a creamy yellow colour.
They have large spots on their backs and flanks (more concentrated to their backs) which are dark red, brown or black and have pale borders. The spots extend onto their dorsal fin which is very attractive.
The male and female fish look similar, however the males have larger heads. They can be distinguished from rainbow trout as they lack the purple stripe on their sides and their caudal fin is plain.
Sea trout are larger than brown trout in general as the feeding grounds in the sea are thought to be richer. They are powerfully build and muscular.
They are generally dark silver on their backs, bright silver on their flanks and have white bellies. Some specimens may differ and be a brown or yellow colour depending on where they are located.
Sea trout have black spots on their backs and flanks and sometimes coloured spots. Their fins are a dark colour which contrasts nicely with the colour of the fish.
Brown trout and sea trout have large eyes. They can focus with both of their eyes individually so they can look in almost all directions at the same time.
Brown trout and sea trout are medium to large fish. The maximum size of this species is around 20 inches (approximately 50.8cm), with the sea trout perhaps growing slightly larger at a maximum size of 25 inches (63.5cm). The lateral line scale count is 110 to 120.
Brown trout and sea trout grow to an average weight of approximately 2kg (approximately 4lb 6 oz). the maximum weight is thought to be around 14kg (approximately 30lb).
The British record for brown trout stands at a whopping 31lb 12oz. The British record for sea trout stands at a slightly lower 28lb 5oz.
Brown trout and sea trout live longer than their cousins rainbow trout. The average age is around 5 years, however some specimens can live from 15 to 20 years.
How they Feed
Brown trout and sea trout are both keen predators. They are both opportunistic feeders and will generally go for any living creature in the water to feed. They are almost always carnivores and will rarely, if ever eat aquatic vegetation.
Young trout will eat insects and invertebrates in the water such as mayflies. As they grow older they become more predatory and will pursue and eat other animals in the water.
Brown trout will hunt smaller fish to feed on as well as invertebrates, insect larvae and crustaceans. The larger fish have even been known to eat small animals such as water voles, mice and frogs.
Sea trout will generally eat smaller fish when they migrate out to saltwater and they will hunt for these as predators.
Brown trout reach sexual maturity between the two to three years of age. At this age the trout will generally be 6 – 8 inches (around 15 to 20cm) in length. The timing of when brown trout spawn depends entirely on the environment.
Brown trout begin to spawn when the temperature of the water reaches 3 to 4 degrees Celsius. This is much colder than many other species will tolerate, however during this time the water carries lots of oxygen which the eggs need to hatch.
In the UK this is generally between the months of November to January. If you are lucky you can often see trout spawn in clear waters around the Christmas break which adds to the magic of the season.
Females will look for areas over gravel with a good flow of fresh water. The female will make a depression in the gravel called a “redde”. Once a female starts to make the redde this will attract the males who will chase each other in the hope that they are in place when the female lays her eggs.
This process can last from a few hours up to a couple of days. Once the male has fertilised the eggs, the female will cover the eggs loosely with gravel.
The eggs are usually a beautiful orange colour and take up to 60 days to hatch. After hatching the juveniles (known as “alevins”) remain in the redde until they have fully consumed the yolk sac, which can take up to 30 days.
Once the yolk sac has been consumed the fry leave the gravel and move towards the lighter areas of water feeding on small insects.
In the case of sea trout, they will migrate to their native river to spawn. They can return to spawn as early as April but will spawn at the same time as brown trout.
They are similar to salmon as they will not eat when they enter fresh water again. Unlike salmon, sea trout do not usually die after spawning and will return to the sea before returning to spawn again.
How to catch
The trout fishing season runs from 1 April to 30 September each year. It is worth researching areas where brown trout or sea trout are present as they are confined to certain rivers or areas of the UK and other countries.
When you have found a suitable location where brown trout are present, they can usually be found under roots or overhanging trees.
Sea trout are almost always caught at dusk or in darkness in the rivers as they hide during the daylight in the river and will rarely leave cover.
Most anglers will fly fish for brown trout and sea trout. It is possible to catch brown trout using a float rod and fishing in a similar way to coarse fishing.
In this case, good baits include worms, maggots, casters, pinkies, mussels, pellets and boilies.
For fly fishing, both brown trout and sea trout can be caught using this method. Sea trout do not actually feed in the river and it is unclear why they take the fly, possible explanations include that they are annoyed by the fly or curious so will mouth it.
For flies, it really depends on what time of year you are fishing however caddis, nymphs and dry flies are a good choice. Wet flies would also work well, particularly for sea trout.
Fly fishing is very different to coarse fishing. With coarse fishing it is perfectly reasonable to stay located in one peg or spot for a day and bag a decent catch of fish.
Fly fishing can be more hit and miss and you need to be much more mobile. Be prepared to walk around to many spots to move to where the fish are likely to be.
Casting is very different with fly fishing and it can really take some experience to get used to it.
Fly fisherman will match their flies to the insects which will be present at the time of year they are fishing.
Try looking online to find which insects are present at the time you wish to fish and try to find these as flies in tackle shops.
In terms of tackle, you need a rod which is sturdy enough to fish beyond the banking but light enough to handle fine nylon leader tippets and small flies.
A carbon fibre rod of 9 foot, which is intended to cast a 6 weight line is perfect for this. Couple the rod with a reel with fly line which floats (for ease of management) together with a backing of 175 yards and a 20lb breaking strain.
A tapered leader of 9 feet with a breaking strain of 3lb is ideal. You can use this tackle to catch both brown trout and sea trout.
Brown trout and sea trout are perfectly normal fish until hooked, however once they are hooked they are such ferocious fighters and leap around so much that the spend more time out of the water than in it.
Putting their aerodynamic abilities aside, this makes for an incredible spectacle, however it does tire the fish. Try not to play the fish too much if you intend to return it to the water as they can easily overexert themselves.
Once the fish is ready either unhook in the water or use a decent landing net (ideally a portable one if fly fishing). You could use rubber net to minimise any damage to the fish.
If you wish to weigh or take pictures try to minimise the time the fish is spent out of the water. Keep the fish wet and put the fish back in the water at intervals to allow it to regain its strength.
If you intend to take the fish home for the pot, make sure you have permission from the owner of the water and check the government guidelines. Dispatch the fish as quickly as possible, perhaps even in the net.
If you would like more information on how to fish for brown trout or sea trout, or would like some further information on angling techniques, check out our fishing tips page for more information!