Can shell scars on dog cockles (Glycymeris glycymeris L.) be used as an indicator of fishing disturbance?

The use of shell damage records as an in situ indicator of past fishing dis turbance was investigated using the dog cockle Glycymeris glycymeris L. She ll sections of dog cockles collected from four areas subjected to varying l evels of fishing disturbance were examined for the presence of damage recor ds or shell 'scars'. Animals from a heavily fished area had significantly h igher levels of scarring than those from three lightly fished areas. From a n estimation of the age of the shells (from internal growth lines and datin g of each line), the year in which scarring occurred was determined and thi s was compared to yearly records of fishing effort. There was a weak but si gnificant positive correlation between the frequency of shell scars per yea r and the intensity of fishing effort. Our data suggest that whilst scarrin g in shells of G. glycymeris cannot accurately be used to estimate past fis hing intensity on a year-by-year basis, it can be used to differentiate bet ween severely impacted and lightly fished areas of the sea bed. (C) 2000 El sevier Science B.V. All rights reserved.