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On the relationship between low winter temperatures and mortality of juvenile scallops, Pecten maximus L., cultured in western Norway

Strand, O., Brynjeldsen, E.
Aquaculture research 2003 v.34 no.15 pp. 1417-1422
Pecten maximus, scallops, juveniles, mortality, seasonal variation, winter, water temperature, cold, mollusc culture, Norway
The mortality of juvenile scallops (Pecten maximus L.) cultured at two densities at 8- and 15-m depth was investigated at 17 trial locations along the western Norwegian coast between latitudes 58 and 65 °N. During the winter of 1995/1996, scallops suffered high mortality at many sites. The results show a clear relationship between minimum temperature recorded on the sites and scallop mortality. All the scallops died at sites where minimum temperatures were lower than 2 °C, while a mortality rate below 30% was only obtained at locations where the minimum temperature was 4-5 °C. At temperatures between 2 and 4 °C, mortality was intermediate, ranging from 52% to 100%. There were no mortality differences between culture densities, while a significantly higher mortality at 8- than at 15-m depth was shown for two of the four sites with a total mean mortality lower than 30%. The results are discussed in relation to low-temperature conditions along the Norwegian coast to suggest risk assessments for site selection in scallop culture.