Mortality of Scallops on a Manx Scallop Bed Due to Fishing

Abstract

Mortality resulting from fishing of scallops (Pecten maximus L.) can be divided into the loss caused by their removal for marketing and the indirect damage inflicted during the operation both by the dredges on the sea bed and the rough handling of undersized discards on board the boat (Medcof & Bourne, 1964; Caddy, 1968). Direct fishing mortality is easily measured if both the relevant biological information and catch data are available. Indirect fishing mortality is more difficult to estimate. Deaths due to damage by the dredges cannot easily be distinguished from natural deaths, and although damage to discards can be assessed before they are thrown back (Medcof & Bourne, 1964), the correlation between such damage and subsequent mortality is almost impossible to obtain in the field.