Abstract
As part of a joint survey of ‘The natural history of the Hardangerfjord’ a study was made of its fish fauna. The investigated area comprises Hardangerfjorden and the system of fjords and sounds between the islands west of it, to the coast. The main field work was carried out during 1956 to 1958 by various kinds of gear, with supplementary investigations in 1959, 1960, and 1963. A total of 186 stations was investigated. The material was supplemented with occasional catches of fishes during other investigations, information from the litterature and local informants, and specimens available in museum collections.
The aim of the survey was faunistic. No attempt was made to study the population dynamics or the detailed ecology of the species. The distribution of each species in the area is described, together with such biological and other information as the material allows.
In all, 126 marine species have been recorded from the area. An anadromous form of Salvelinus alpinus has also been observed, and there are 9 further species, for which there is not specific enough information to include them at present in the fauna of the investigated area.
Of the 126 species, 26 are considered more or less occasional visitors, 11 others are stationary only in the outer part, outside the fjord itself. The deep waters of the investigated area, that is, below about 100 m, are very uniform as to temperature and salinity throughout the year, and the corresponding fish fauna is also very uniform. The shallow-water fish fauna, down to about 10 m, at 13 serial stations from the outer coast to the inner fjord branches was investigated five times. The fauna, grouped into four subareas, is described, and the number of species in each is compared with earlier findings for the hard-bottom littoral fauna and for the benthic algae. While there was a clear reduction in the number of species in the two last groups from the coast to the inner fjord branches, no such reduction was found in the number of fish species. For many species there was, however, a clear reduction in the number of specimens from the coast inwards. The shallow-water fauna showed a marked difference between February, when it was fairly poor, both as to species and specimens, and the period June to October/early November.
