Fish disease monitoring along a pollution transect: a case study using dab Limanda limanda in the German Bight

Abstract

A survey of dab Limanda limanda at 6 stations along a pollution gradient in the German Bight was conducted as part of the Bremerhaven Workshop in order to quantify spatial patterns of 5 selected gross pathologies. The objective was to test the suitability of disease epidemiology and related histological investigations in this species as a technique for monitoring environmental quality in offshore waters. In 2 surveys. 7565 dab (length 2 15 cm) were examined post-mortern and the following externally visible diseases (with overall prevalences) were recorded: lymphocystis (10.5 %), epidermal hyperplasia/papilloma (6.2 "61, acute and healing ulcerations (1 7 %) and X-cell gill disease (0.4 %). In the 1st survey, a total of 686 dab (length 2 2 5 cm) were screened Internally for nodular lesions (diameter 2 2 mm) on the liver surface These liver nodules represented presumptive neoplasia (5.8 %).