Published Jun 1. 1995 - 27 years ago
Updated or edited Jul 17. 2020

Sea trout

The key to success in the pursuit of sea trout in salt water on the coasts of the Baltic Sea is understanding some important aspects of the trout's behavior in respect to the seasonal changes. The sea trout i salt water can't be fished the same way all year. Some key factors here are water temperatures, currents, the wind and the trout's migratory patterns.

Sea Trout (Sea Run Brown Trout, Salmo trutta) in the Baltic Area

Notice that this description has been supplemented with list of our sea trout articles.

This section is the manuscript for chapter in a book on fly fishing in salt water in Northern Europe. The subjects covered here are also covered elsewhere on this web site. There are links to all relevant pages.

The key to success in the pursuit of sea trout in salt water on the coasts of the Baltic Sea is understanding some important aspects of the trout's behavior in respect to the seasonal changes. The sae trout i salt water can't be fished the same way all year. Some key factors here are water temperatures, currents, the wind and the trout's migratory patterns.

A brief (natural) history

This text will discuss fishing in the Baltic area - which includes the coasts of Denmark, Germany and part of Sweden. It alsom covers Poland, the Eastern Baltic countries and Finland although sea trout fishing in the salt is rarely heard of in these countries. Of the countries mentioned, Denmark has the longest tradition for fly fishing for salt water trout, and many of the ideas and tactics used in the whole area come from Denmark. Sea trout fishing in other parts of Europe will probably differ from this in several important areas, although much of the advise given here will be applicable in other waters.
The brown trout Salmo trutta has a few different life patterns. One is the well known stream dwelling type, where the fish will be stationary in a stream for its whole life, only moving short distances to spawn. The two others include a longer spawning migration into a stream, but are significantly different because the fish live most of their life in either a lake - becoming a lake trout, sometimes referred to as landlocked trout - or in the sea - becoming a sea trout. Genetically there is no difference between the three.
The sea trout is born as other trout in a stream, but will wander into the sea to eat after its first year. The trout will typically stay in the sea for a couple of years before one autumn returning to its stream of birth to spawn. It will then stay in the stream or the estuary during the winter and return to the sea in the early spring to feed during the summer and early autumn.
In this period the majority of the sea trout will stay close to the shoreline in shallow areas, making them a very suitable game for the fly fisher. Changes in their environment will make them move or stay in certain areas, but generally they will be close enough to catch on a fly.
Mature fish will occasionally skip spawning, and stay in the sea to eat all winter. But because of certain physiological circumstances, the fish can't stay on the open coasts when the water gets too cold, but will have to find either warmer water or water with less salinity.
Like elsewhere in the world, the Baltic trout have too few quality streams to spawn in, and probably wouldn't be able to reproduce naturally. But thanks to extensive stocking in streams and in the ocean, the fish are quite abundant in the area. The largest and oldest fish are rare, though, mostly because they stay longer in the streams and migrate into the deeper parts of the ocean to feed on pelagic fish.
Fish caught near the coast will typically range from 0.5-1 kilo (1-2 lb.) and up to 5 kilos (10 lb.). The sea trout will grow to 10-15 kilos and even more, but getting such a fish on a fly from the coast is very unlikely - albeit not impossible. Notice that many countries have limits. In Denmark it's 40 centimeters (16") and in Sweden 50 (20").

What and how sea trout eat

The trout that live close to the coast feed on large numbers of fairly small animals. Their diet is a combination of small crustaceans (like Gammarus), shrimps, fry, smaller fish like sculpins, sticklebacks, sand eel and different worms.
The trout are fierce and avid hunters that move swiftly in the water and have very keen senses: smell, sight and pressure sensed with the sideline. But trout will also sometimes browse the vegetation stirring out smaller animals or rest near the bottom in still or moving water, and attack prey passing by.
Like trout in running water, sea trout are more alert and cautious in calm water and more reckless and aggressive in turbulent water. This can be used to the advantage of the fisher in the choice of tactics and tackle.


7-8 wt., 9-9.5' single hand tackle is considered ideal by most sea trout fishers. You can easily do with lighter tackle on calm days as most fish are fairly small, but in order to overcome wind and other tough conditions it can be necessary to go up in weight. The typical U.S. salt water tackle encompassing 10-12 wt. single hand rods is vastly overkill both in regard to conditions and the size of the fish.
The line of choice is a floating line - either a weight forward or a shooting head combination. Some conditions call for a sink tip or intermediate line, but the one line setup should be a floater.
Contrary to what most people think, casting distance isn't crucial here. But if you use a shooting head setup you can expand your range and - not least - the sense of covering enough water.
Leaders should be anything from 2-6 meters (6-18') depending on conditions. The tippet could be anything from 0.18 millimeters (4X) to 0.28 (0X) again depending on the fly, tackle and conditions. Normally a 0.20-0.23 millimeter (2X or 3X) tippet would suffice.
No matter what type of rod and reel you use you should bear in mind that you are fishing in salt water and that the salt will eventually kill anything - even the salt resistant gear - if you do not take care.


If you have the choice of one single fly, choose a black or gray Woolly Bugger size 6. This fly represents the stem of many of the most successful flies for sea trout in salt water.
The variations in native flies are of course endless. Most patterns are fairly simple and robust, and almost any shrimp, fry or streamer pattern in the size range 2-12 will be a potential salt water sea trout fly.
Again: do not be tempted by the American way of doing things. These large, colorful flies are meant for a totally different kind of fishing for different species and sizes of fish. A few patterns will be useful in scaled down versions, but on the average these flies are both too large and too flashy. A better choice will be traditional sea trout flies meant for stream use. But have them tied in smaller sizes and on single hooks. The best advice is to buy your flies locally and heed the advice - and generosity - of local fly fishers. If you are a fly tyer, try to get your hands on some patterns to copy.
All flies no matter what source should be tied on stainless or salt water resistant hooks, as a single day in - or even near - salt water will stain and eventually ruin any fly on a normal fresh water hook.


As all other kinds of fishing, the hunt for sea trout varies greatly through the year. But opposite many other fishing, there's no low season or high season. The fishing can be almost equally good all year round, except maybe for the hottest weeks of warm summer and the coldest weeks of cold winters. In the winter the fish will be most active in sunshine and in the summer most active at night. Spring and autumn calls for fishing in the mornings and evenings.

Spring - March, April, May

In the spring all fish are beginning to eat again. The spawning fish return to the sea and all fish leave the fjords. They eat everything as long as it's big enough. So flies aren't always the best, even though larger lures, shrimps and streamers of different kinds can trap many fish. For those not fishing flies, the spring is probably the best season. The fish are hungry and very willing to eat large bait, such as sand eels and small herring. These are easily imitated with lures.
Fishing gets better as water warms, and can be good on sunny days even in January. In the early spring it's all day, but later on in April and May, the action is early morning and evening. You can start out fishing the fjord and estuary areas in January and March, and the move out to the open coasts as the water gets warmer.
Fish will go for large flies (zonkers, streamers, silvery flies etc.). Early spring is for fishing shallow waters with dark bottom, but when temperatures go up, deeper water with sandy bottom will fish good too.
Fish are fast, take the fly with a bang, almost always hooking themselves, and offer a good fight. A lot of fish have to be released again because of their poor post spawning condition. If you want to keep fish, keep only those that are pure silver with loose scales.

Summer - June, July, August

Summer is for harder fishing. Late evenings and nights when the water cools off are best. Fish don't migrate any more, but often stay in small areas. You have to fish at these places which typically have deep water close to the shore and a lot of circulation. In the high summer in years when water temperatures are extremely high, the fish won't even come close enough to the shore to reach wading.
Fish can be very active in the surface and muddlers are an old time favorite, but other bushy, highly profiled flies will do. For the darkest night a bit of flash can make many patterns more efficient.
Water movement is the key. In the summer coastal points and reefs below the surface are the places to seek. Fish in the 'back water' meaning behind the reef that you'll often see below points on the shore. If the current goes right, fish on the right side and vice versa.
Fish are more shy than in the spring. They will nibble the flies and follow without taking. They offer excellent sport, and drilling a large trout in the dark night can really get your heart pounding. Summer is the skilled and patient fisherman's season.

Autumn - September, October, November

Autumn is ideal for catching top condition fish, mornings, days and evenings. The fish are typically stuffed with the smallest animals, and small brown/gray flies are therefore best. If the fish do not react to these small flies a good wildcard can be to switch to a huge, colorful fly like a large Mickey Finn. You will occasionally run into large schools of fish, which you either see or notice by catching several trout in a row. Try to stay with them while they are moving.
Still, fish can be picky and difficult, but sport is even better than in the summer, and the beautiful, silvery, well conditioned fish offer the best food of all year. But note that all brownish colored fish should be released as they are on their spawning run.
Temperatures are dropping, and when the water is between 6-12 degrees Centigrade, fishing is at its best. Fish will go very close to the shore, and you should always fish before you wade. Fish can typically be everywhere, not only in fjords or places with good circulation, but also on open, sandy beaches because they are migrating towards the spawning streams or winter dwellings.

Winter - December, January, February

In the real cold winter, the trout has to seek freshwater because it can't tolerate salt due to difficulties with osmotic regulation. Hence the fish are found in streams, estuaries and brackish fjords. For the salt water fisher, the fjords and shallow waters can offer good fishing in the winter.
The fish don't eat much and move very slowly, but even with ice on the shore, the fish often go for flashy, happy-colored (red/orange/purple), deeply fished, slowly retrieved flies. This is the time of year to use a sink tip or sinking line. The fishing is best on mild and sunny days in shallow water over dark bottom.
It can be a good idea to observe where there are fresh water currents from stream or other outlets, but at the same time notice that fishing for trout often is prohibited in and near estuaries and in some countries on the whole coast in the winter.


The wind has a strong influence on the behavior of the water, its temperature and the activity of food organisms and trout. The following illustrations all show the situation when a wind is blowing off shore in the four seasons, and show how water will be moved and affect the temperature.
On shore wind will rarely have the same influence as offshore wind because the wind will only stir the near shore water and not move it very much. Stronger wind might move in surface water from further out towards the coast, but as this surface water will often be the same temperature as the near shore surface water, the overall effect on temperature is relatively small.
But... and there's a big but, onshore wind will stir the shallow water and bring lots of food and debris in suspension. This makes the water unclear and full of food and can mean ideal conditions for hunting fish.
Most fishers will prefer offshore winds which normally means wind in the back, but some people routinely choose onshore wind - and catch a lot of fish.



Martin Joergensen's picture

Sea trout are eaten ...

Sea trout are eaten by many predators, mainly seals, comorrants, otters, herons, porpoises and larger birds of prey like fishing eagles.

Smaller fish (fry and smolt) are eaten by larger fish including its own kin and salmon.


Who eats the sea tro...

Who eats the sea trout?


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