Hydrological conditions at the spawning grounds of Atlanto-Scandinavian herring
Tr Polyar Inst Proekt Inst Morsk Ryb Khoz Okeanogr 17: 113-123
In 1965-63 observations were made on temperature and salinity distribution at the spawning grounds of the Atlanto-Scandinavian herring. Measurements were made in Feb.-April on the surface of the water, at a depth of 50 m and near the bottom. At the spawning areas of the Faroe and Hebrido-Shetland shallows, the year-by-year fluctuation of near-bottom temperatures was 2[degree], and to 3[degree] off the Norwegian coast. Minimum near-bottom temperature off the Faroe Islands was 5.5[degree] (1963); maximum, 7.52[degree] (1960); at the Hebrido-Shetland spawning grounds the corresponding data were 7.67[degree] (1955) and 9.70[degree] (1959-60). The near-bottom temperatures at the herring spawning sites in the South Norwegian channel fluctuated during the observation years from 5.96 to 7.90[degree], and the salinity from 35.08 to 35.34%; in the Norwegian shallows the corresponding values were 5.17-8.12[degree] and 34.42-35.23%.