The Atlantic salmon (Salmo salar) has for ages been the icon for migrating fish as well a symbol of vitality. His name means ‘the jumper’ in Latin, referring to the legendary capacity to jump over water falls that are insurmountable for most other fish species.
Since about 40 years the Atlantic salmon populations are declining in all its original habitats. Much earlier – around 1950 – there had been the demise of the once famous populations of the rivers Rhine and Meuse. It proved to be a sad warning of more to come. The downfall of the Atlantic salmon in these great European rivers should have been a forewarning for everybody. However, its causes were so complex and they were not very well understood. Actually, they were never thoroughly studied since nobody seemed to pay attention.
The current decline of Atlantic salmon worldwide is also caused by many factors, and consequently there lurks the serious danger that because of the sheer complexity of all these problems, no actions are taken to correct them.
With this position paper the European Anglers Alliance wants to present an overview of the main problems confronting the Atlantic salmon and to suggest some possible solutions for these problems.
Life cycle
In late autumn or winter, Atlantic salmon spawn on the gravel beds of rivers and streams that ultimately flow into the sea. February to June, about three to seven months – depending on the water temperature - after the eggs were deposited, the young salmon hatches and after another month or two leaves the safety of the gravel and embarks on a hazardous journey out into the open stream. During the course of the next years, the young salmon grows, moving downstream to deeper waters and eventually – after one to four years - makes its way out to the sea as a “smolt”. There it will stay for at least one year, feeding on smaller fish or crustaceans and growing at a very fast rate. Most salmon however stay two to three years in the sea or ocean.
Salmon that already return in the summer of the year following their journey into the sea, are called “grilse”. Salmon that stay two or more years in the sea are called ‘multi sea winter’ salmon or MSW salmon. So after one to three years in the sea, the adult salmon begins a return journey which will bring it to the stream in which it was born. It swims gradually upstream where it spawns and thus begins the life cycle of the next generation of salmon.
Migration barriers
Despite the reputation as a great leaper, there are man-made barriers that are insurmountable for even the Atlantic salmon. Some other barriers are less tough, but seem to slow him down during the migration in such a way that adult salmon do not reach the spawning grounds in time or even turn back to the sea instead of taking part in the spawning process. On the other hand barriers can prevent young salmon (smolts) from reaching the estuary and the sea.
Migration barriers and hydro power stations also make salmon – both young and adults - more vulnerable for predation by fish, birds or mammals.
Man-made migration barriers come in many guises:
- Weirs, dams and sluices for shipping, commercial fish farms, water management and flood control;
- Weirs and dams for hydropower and irrigation;
- Large bodies of stagnant water created by the impoundments.
People need weirs, dams and sluices for their safety, for transport and for the production of food as well as energy. But these man-made barriers can turn free flowing rivers into obstacle courses for many migratory fish species. In most cases these structures were built without any regard for the needs of these fish. With the help of fish passages salmon can navigate most of these barriers. Other solutions - depending on the problem - include: fish lifts, guidance systems and a different sluice management. Most preferable are fish passages with full water flow capacity.
Hydropower is a problem in its own right (also see the EAA position paper on hydro power). Hydro power stations (and the dams or weirs that come with it) not only constitute serious barriers for upstream and downstream fish migration, but also kill downstream migrating fish, like young salmon, in their turbines right away.
An additional problem constituted by hydro power and the necessary impoundments are the profound changes they bring about in natural river systems.
Fisheries
Wild Atlantic salmon are valued as game fish and as a fish for the table. The catch by commercial and recreational fishermen may have an impact on salmon populations. Fishing for salmon is done at many places and carried out in many different ways. In most cases recreational angling for Atlantic salmon generates substantial higher financial rewards for the local communities than does commercial fishing and with less negative impact on the stock.
In many European countries - the North Sea region in particular, including the river systems of the Rhine and Meuse - the Atlantic salmon is protected by EU Directives and national laws. In some places all salmon caught there by rod and line or nets must immediately be released.
Commercial fishing in rivers – especially for fresh-run salmon in the lower parts – used to be economically very important, but it has in most countries given way to the much more profitable recreational angling and sport fishing for salmon. The economic value of a salmon caught by sportfishing can be up to 30 times
the market value of a commercially caught salmon (counting investments in tackle, travelling, lodging, food, licences and guiding). To protect the resources even further – ensuring that enough salmon can take part in the spawning process -, on some rivers recreational and sport fishing are made subject to additional management like catch and release. On other rivers catch and release is practiced on a voluntary basis with very good results. On some rivers even more fine tuned management tools are introduced, like increased minimum sizes, slot sizes or catch and release of female fish only.
To promote recreational angling and sport fishing for salmon as well as protect the spawning population of salmon it is important to ban all commercial fishing for salmon in the rivers.
Commercial fishing also takes place in river deltas, estuaries, coastal waters and the sea. Especially the mixed stock fisheries (MSF), where salmon originating from several rivers of many countries are caught, are very harmful because in many cases these fisheries catch salmon from already depleted populations..
The commercial fishing for salmon on their feeding grounds in the Atlantic Ocean is nowadays severely limited. Unfortunately this had little visible effect on the declining survival of the Atlantic salmon in the Ocean. (At least it could not prevent a further decline)
The commercial fishing for prey species or other fish in the northern Ocean does however still harm the Atlantic salmon in a direct as well as in an indirect way. Salmon are by caught in herring and mackerel fisheries as well as in the industrial fishery for fish food. In the large scale industrial fishery for capelin, sandeel, herring, barracudinas, shrimp and krill, the most important prey species for Atlantic salmon are removed from the food chain, possibly leading to food shortages for the salmon and lower survival rates in the ocean.
Salmon farms
Many independent studies show a direct relationship between the increase of commercial salmon farms and the decline of wild salmon populations in nearby rivers.
The effects of salmon farms on wild salmon are manifold:
- Large numbers of escaped salmon