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2N - Field Studies (MOP/135) Survey on reproductive success in the viviparous blenny (Zoarces viviparus) in Danish waters. Strand, Jakob1, Dahllöf, Ingela1, 1 National Environmental Research Institute, Roskilde, Denmark, Denmark ABSTRACT- The presence of malformations in broods of the viviparous blenny has been suggested to be a useful indicator of the impact of hazardous substances on fish in the marine environment.Chronic exposure to different kinds of neurotoxic and endocrine disrupting substances like heavy metals, organotins, organochlorines and alkylphenols has been shown to have the potential to induce severe developmental effects on fish embryos. Sampling was performed during October and November 2001 and 2002 in 10 different Danish coastal areas. Increased prevalence of different types of malformations occurred in broods from some of the shallow fjord areas with effluents from larger cities and industry compared to areas, which were regarded as less polluted reference areas. The distribution pattern between different types of embryo malformations varied between the areas. In some areas deformations like spirality or other malformations of the vertebral axis were the dominating types. In other areas, abnormalities like head deformations, eye lesions or entirely loss of eyes were more dominating. These variations may be due to differences in pollution patterns between the sampling areas. In some areas relatively high proportions of juveniles in the broods have died acutely, but without any visible developmental malformations. These areas were known to have been affected by oxygen depletion, and in a pilot experiment it was confirmed that oxygen depletion could cause acute death of juveniles. This may suggest that examination of broods in the viviparous blenny can be a method to integrate monitoring on the impact of hazardous substances and eutrophication on fish in the marine environment. Key words: Embryo malformations, Zoarces viviparus, Fish, Denmark |
