Le lac d’Allos
(Alpes-de-Haute-Provence). Sanctuaire et laboratoire de l’évolution
pour l’omble chevalier du léman (Salvelinus alpinus ;
Salmonidae)
Yoichi
MACHINO (1) & Bernard RIVIER (2)
(1) 13 rue
Montorge, F-38000 Grenoble, FRANCE.
(2) Division Hydrobiologie, CEMAGREF, Le Tholonet, BP 31, F-13612 Aix-en-Provence
cedex 1, FRANCE.
Résumé.
- Les recherches bibliographiques révèlent que l’omble
chevalier (Salvelinus alpinus) n’est pas une espèce
autochtone dans le lac d’Allos (Alpes-de-Haute-Provence). Il aurait
été introduit dans les années vingt du 20e siècle
à partir d’une souche provenant du Léman. Son pool
génétique n’aurait pas été perturbé
depuis son acclimatation en raison de l’absence de repeuplements
ultérieurs. Il y forme actuellement deux populations distinctes.
Des études de biologie et de génétique des populations
sont nécessaires pour préserver ces ombles chevaliers si
particuliers et aider à la préservation du lac d’Allos
lui-même.
Abstract. - Lake Allos (Alpes-de-Haute-Provence).
Sanctuary and laboratory of evolution for the Arctic charr of Lake Leman
(Salvelinus alpinus; Salmonidae).
Arctic charr (Salvelinus alpinus) is a cold-water salmonid that
was recorded in the Red Data Book of threatened species in France although
its geographical distribution continues to extend and it has been established
now in 138 lakes in France. Lake Allos (a French lake in Department of
Alpes-de-Haute-Provence, 2229 m a.s.l.) possessed Arctic charr of
unknown origin. Therefore the origin was researched in the present paper.
Till the 1910s this fish had not been known from Lake Allos. There was
a project of Arctic charr introduction in 1922 (but result is unknown).
For the first time this fish was reported in Lake Allos in 1923. In 1924
the lake was further restocked with the same species. Arctic charr therefore
seems not to be native to this lake. In 1800 only three French lakes were
reported to contain Arctic charr (Lakes Leman, Bourget and Paladru). Salvelinus
alpinus was in fact a fish of low altitude in France. The notion of
“Arctic charr, a high-altitude fish” was not due to a natural
distribution but to a long history of artificial stockings into high-altitude
lakes through the 20th century in France and Switzerland or since the
Middle Age in Austrian Tyrol and Italy. Since its introduction during
the 1920s Arctic charr lives in Lake Allos. Its original strain would
be from Leman, and genetic pool seems not to have been disturbed since
that time because no further stockings would have been carried out. Lake
Allos therefore contains a pure strain of Arctic charr (of Lake Leman).
After several decades of acclimatization, S. alpinus formed two
distinct populations in Lake Allos. Population biology and genetics are
important for providing data necessary for protection and management of
Arctic charr and Lake Allos. Together these belong to natural heritage
of France.
Key words. - Salmonidae - Salvelinus alpinus - France -
Lake Allos - Biogeography.
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