The Fish Disease Index: a method to assess wild fish disease data in the context of marine environmental monitoring

Based on empirical data derived from the German long-term fish disease monitoring programme, a Fish Disease Index (FDI) has been developed that provides numeric information on the overall disease status of individual fish and on temporal changes in the disease status of fish populations. Furthermore, the FDI approach offers a method for regional assessments of FDI levels and trends and for regional comparisons thereof. Examples illustrating the construction and application of the FDI approach are given, using data on diseases of the common dab (Limanda limanda), the major target species in the North Sea and adjacent areas. The potential of the FDI approach in the context of international marine monitoring and assessment programmes such as the OSPAR Coordinated Environmental Monitoring Programme (CEMP) is highlighted