Onema

Home - Mission - A Four Part Strategy

  • Ecological continuity Vezins Poutes

    A film directed by EDF, Onema and the Seine-Normandy water agency
    showing two major examples of restoration continuity on two French rivers

  • The 31st Genreal Assembely of NASCO, the North Atlantic Salmon Conservation Organization

    organized with the support of Onema, took place in Saint Malo from the 3rd to the 6th June 2014 The official website

  • The Atlantic Salmon in France

    Overview, Fisheries, Habitats restoration, Restocking...

    With contributions from B.Valadou, A.Richard, MA.Arago, M.Chanseau, V-Vauclin and V.Burgun (Onema)

THE FUTURE OF SALMON IN OUR RIVERS AND OCEANS

Atlantic salmon, the great migratory fish symbolising water quality, are in decline both in France and throughout the North Atlantic Ocean. The 31st Annual Meeting of NASCO, the North Atlantic Salmon Conservation Organisation was held in Saint-Malo from 3 to 6 June 2014, with organisational support from Onema. The meeting is a chance to review the situation for Atlantic salmon and the management policies implemented to conserve and restore salmon stocks.

Atlantic salmon are certainly the most emblematic of diadromous fish and cover the greatest distances, often thousands of kilometres in rivers and the ocean. Their migration takes them to Greenland and the Faroe Islands, whose fisheries are regulated by NASCO. They then return to reproduce in fresh water, generally in the upper reaches of rivers where they were born.

General decline?

Salmon stocks are at historically low levels and in some areas are critically low. Over the past 30 years, stocks have declined by 75% in the North Atlantic. It is thought that salmon stocks in the North Atlantic at the beginning of the 1970s represented a population of 10 million, whereas the population is currently estimated at only 3.6 million. Catches have dropped from 12 500 tons in the 1970s to 1 300 tons today. That represents the lowest capture rate over the past several years. The steepest declines have affected salmon spending multiple winters at sea (MSW) and taken place in the North American zone and the Southern European zone.

 

Percent decline prior to capture, over past 30 years
1SW (one winter at sea)MSW (multiple winters at sea
Northern Europe49%54%
Southern Europe66%81%
North America40%88%

Research to save the Atlantic salmon

An array of factors contributes to the decline in salmon populations, both in rivers and in the ocean. In rivers, research has improved our knowledge of the causes of the decline. Clearly identified factors include infrastructure (dams, weirs, etc.), other obstacles to migration and water pollution.

In the ocean, however, mortality rates are high and there is still little known about the causes of the mortality. That is why NASCO is currently running a major research programme on the factors influencing salmon in the ocean. This work has shown, for example, that global change in the marine environment has created additional pressures weighing on salmon, particularly in the southern section of its range. In light of these results, the objective is to ensure that a maximum number of healthy smolts (juveniles) reach the ocean by addressing the impact factors in rivers, estuaries and coastal waters. In Saint-Malo, a large-scale, international tracking project will be launched to gain information on migration paths and estimate mortality rates during the long journey of the salmon across the ocean.

Better manage human activities to preserve salmon

NASCO has developed agreements on the management of salmon fisheries, habitat protection/restoration and aquaculture and related activities. Each NASCO party/jurisdiction has prepared or is preparing a fiveyear plan detailing the measures taken to implement the NASCO agreements. Reports on the progress over the first year of the plan will be presented in Saint-Malo. A wide range of efforts is currently under way to conserve and restore salmon around the North Atlantic, including:

  • further reductions in netting effort and increased use of "catch and release" policies in recreational fisheries;
  • habitat improvement, including work to mitigate the impacts of climate change, to improve water quality and to remove barriers to migration, for example, the 60 million USD programme that resulted in the elimination of the Veazie Dam on the Penobscot River in the United States;
  • measures to minimise the impacts of salmon aquaculture and prevent the spread of the parasite Gyrodactylus salaris.
  • A major focus at the meeting will be the management of fisheries working on single stocks and mixed stocks (i.e. comprising fish from at least two different rivers), with particular focus on fisheries working stocks below their conservation limits. The Meeting will also consider how advances in genetic assignment techniques can assist in the rational management of mixed-stock fisheries.

    The situation in France

    In France, Atlantic salmon are still present in approximately 50 rivers, primarily the Rhine and the rivers along the Atlantic coast (Loire, Garonne, Dordogne, Allier, Nivelle, Adour, etc.), unfortunately the populations are very small in number and some are on the road to extinction. Since 1900, the number of kilometres of river serving as salmon habitats has dropped 70%. In the 1800s, the Loire River had a population of approximately 100 000 salmon, but they currently number less than 1 000 throughout the entire basin, a quantity below the minimum threshold required to maintain the stock.

    Two priorities in the efforts to save the salmon in French rivers are habitat preservation/restoration and work to facilitate migration, both upstream and downstream, that is currently blocked by numerous obstacles in rivers (dams, locks, weirs, etc.). France has committed to launching a national plan for ecological continuity and a protection policy for large migrators, such as salmon. In its day-to-day work, Onema participates in the efforts to protect and restore Atlantic salmon by:

    • improving knowledge on obstacles and habitats, required to provide technical support to local governments and environmental groups;
    • organising research, notably with the research centre in Toulouse, on how fish can overcome obstacles and on the continuity of sediment transport;
    • fighting poaching, among other issues, via the water police.
        • 1700s
        • End of the 1800s
        • End of the 1900s