Presence of two populations of Norwegian topknot, Phrynorhombus norvegicus (Pleuronectiformes : Scophthalmidae), in western European seas.
|Author(s)||Chanet B, Quetro Jc, Vayne Jean-Jacques|
|Affiliation(s)||Univ Bretagne Occidentale, European Univ Inst, F-29280 Plouzane, France.
Nat Hist Museum, F-17000 La Rochelle, France.
IFREMER, F-17137 Houmeau, France.
|Source||Cybium (0399-0974) (Soc Francaise D Ichtyologie), 2003 , Vol. 27 , N. 3 , P. 227-232|
|Keyword(s)||Scophthalmidae, Phrynorhombus norvegicus, Western European seas, populations|
|Abstract||Presence of two populations of Norwegian topknot, Phrynorhombus norvegicus (Pleuronectiformes: Scophthalmidae), in western European seas.
The Norwegian topknot Phrynorhombus norvegicus (Gunther, 1862) is a little flatfish belonging to the scoplithalmid family. Generally, in the literature, the habitat of this species is mentioned to be rocky bottoms of the north-eastern European seas between 10 to 180 in depth, while few references noticed its presence in the same area and depth on muddy bottoms as well. A study of fisheries data conducted by the trawlers of ISTPM and IFREMER between 1976 to 2001 in Celtic sea and Bay of Biscaye shows that Norwegian Topknot is a rarely caught species with 423 specimens fished in 25 years. Moreover, this analysis leads to the conclusion that two groups of Norwegian topknot are present in western Europeans seas: one occurs on rocky substrates from the Celtic sea northwards, whereas another one is present more southwards on muddy substrates off the Bay of Biscay, the species being more abundant in the latter area. Gene flow exchange between these two groups could not be demonstrated yet. Only further studies based on meristic or molecular data could clarify the status of these local populations.