Sea Trout Fishing Biology

The eggs of Sea Trout are laid high in rivers and streams in areas known as redds. From here their development begins and eventually the small fish hatch. At this stage, known as Alevin they are sustained by a yolk sack, which provides nourishment to give them a good start.

As they grow the Yolk sack is used and disappears, the young fish becoming Parr, dependant on their resources to feed.

Sea trout, brown trout and even Salmon Alevin inevitably share the same rivers and nurseries. A juvenile sea trout parr is very similar in appearance to the juvenile brown trout; markings are similar and both may share the same stretch of nursery. As a sea trout grows its genetics change and anatomically it
develops organs that a brown trout lacks. As parr become smolt, herling or peel, it develops salt secreting glands in its gills and changes colour from its brown trout characteristics, eventually resembling a salmon more than a trout.

The reason for this is a much debated subject, however I feel it can be looked at from two differing aspects:

The sea trout is something of an enigma. Seldom seen in the estuaries and sea that are its home for part of the year, the sea trout runs back to rivers and streams every spring and summer to spawn. Firstly I should explain a little science behind this brave and resourceful fish. Genetically there is no anatomical difference between the sea trout and the brown trout. Both share the same Latin name 'Salmo Trutta.' It is here where the similarities cease. However the Rev. W. Houghton in his 1879 Publication 'British Freshwater Fishes,' refers to the Welsh Sewin as 'Salmo Cambricus' It appears that the Reverend's classification was forgetten for some years and now the fish is simply classified as 'Salmon Trutta.'

TO FEED or NOT TO FEED? THAT IS THE QUESTION.

It is generally accepted that salmon and sea trout do not feed on their return to spawning grounds. Both fish will live on reserves they have built up whilst at sea. So why do we angle for them? The schools of thought behind this theory are varied. Let me explain.

Firstly, I believe that a fish that has been in fresh water or tidal stretches for a day or so may take bait more avidly than a fish that has been a river for some time. However, more fish are caught in fresh water than in tidal waters. The reasons for a fish taking a bait are not known but could be explained by the following:

1) A fish takes an imitative pattern of fly i.e. Teal, Blue & Silver or Falkus’s sunk lure because it represents a sand eel, one of the staple foods of the sea trout whilst at sea. It will take this from habit, forgetting that it is now going to spawn and is needless of food.

2) A fish will take a due to aggression, snapping at a well presented lure, not feeding but attacking, a reaction of a fish feeding at sea.

3) A fish will take a bait that has entered its territory merely to ‘clean its house,’ meaning that it doesn’t want our bait messing up an area where it MAY spawn.

4) A fish may take a bait for feeding's sake.

These are just a few ideas to think about. However, this is not a definitive list. I myself have had nights when I have caught well and believed that the fish are feeding, yet these nights are few and far between.

Rather than approach the river to hunt for a feeding fish it is better to assume that they are not. Do not concentrate solely on imitative patterns, but ‘Ring the Changes’ trying different methods and fly patterns.

Point 1 above interests me as, ‘why will a Sea Trout take a surface or wake lure at the dead of night?’ What does this represent?

Mainly our fishing will be at night. I will explain this later. However during the right conditions sea trout can be caught in the day and conversely salmon can be caught at night.

Basically, there are rules outlining the best times to fish and how to fish. However, DO NOT let this put you off. The key to catching fish is one thing, and one thing alone,

CONFIDENCE

For further details I would recommend the Peter Jarrams Book, Sea Trout Run, details can be found in my Bibliography Page.

A) There is too little food in the nursery streams to sustain the number of parr. Some fish undergo a genetic anatomical change in order that more food can be obtained in the rich feeding grounds of estuaries and the sea.

B) That some Brown Trout manage on what food is to be found in their river, thus negating the need to change and run to sea. I believe that this is why brown trout in Spate rivers remain smaller than their brothers that run to the sea.

However, this is my opinion and others may disagree. Numerous people with far more years of experience in catching these fish have a differing view. I ask you to form your own opinion as to the reasons for this change, however do not dwell on it for too long!

The sea trout smolt then run to the sea. Some will return in their first summer to spawn, others remaining at sea before returning the following spring. Dependant on their luck the sea trout will then return from their salt water homes to their home rivers every year to spawn. The life expectancy of a sea trout cannot be high -
many predators await their return. However, it is believed that some sea trout have had multi-winters at sea and may live into years numbering double figures.

As for salmon, these magnificent fish usually return to the river where they were born, it is believed that they can sense or smell the river, to the extent that they spawn within yards of their birthplace.

N.B. Some sea trout from North Country rivers will be found in West Country rivers, the reason for this is unknown.

I have also found that sea trout may differ in appearance from river to river, county to county i.e. River Towy sea trout may have fewer spots than sea trout caught in the Rivers Wnion and Artro. This difference may be seen in different areas of the U.K and throughout the world. If you think of the differences in brown trout
characteristics i.e. The Leven strain, you will appreciate that not all sea run brown trout will look the same.


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		The eggs of Sea Trout are laid high in rivers and streams in areas known as redds. From here their development begins and eventually the small fish hatch. At this stage, known as Alevin they are sustained by a yolk sack, which provides nourishment to give them a good start. As they grow the Yolk sack is used and disappears, the young fish becoming Parr, dependant on their resources to feed. Sea trout, brown trout and even Salmon Alevin inevitably share the same rivers and nurseries. A juvenile sea trout parr is very similar in appearance to the juvenile brown trout; markings are similar and both may share the same stretch of nursery. As a sea trout grows its genetics change and anatomically it develops organs that a brown trout lacks. As parr become smolt, herling or peel, it develops salt secreting glands in its gills and changes colour from its brown trout characteristics, eventually resembling a salmon more than a trout. The reason for this is a much debated subject, however I feel it can be looked at from two differing aspects:	The sea trout is something of an enigma. Seldom seen in the estuaries and sea that are its home for part of the year, the sea trout runs back to rivers and streams every spring and summer to spawn. Firstly I should explain a little science behind this brave and resourceful fish. Genetically there is no anatomical difference between the sea trout and the brown trout. Both share the same Latin name 'Salmo Trutta.' It is here where the similarities cease. However the Rev. W. Houghton in his 1879 Publication 'British Freshwater Fishes,' refers to the Welsh Sewin as 'Salmo Cambricus' It appears that the Reverend's classification was forgetten for some years and now the fish is simply classified as 'Salmon Trutta.'