Temporal and spatial variability in dredging induced stress in the great scallop Pecten maximus (L.)

Temporal and spatial variability in the stress caused to the great scallop Pecten maximus by dredge capture was determined using the adenylic energetic charge (AEC) of the striated muscle as an index. Samples were taken on a seasonal basis from dredge captured scallops of a single fishing ground in the north Irish Sea. All samples were taken from individuals under the minimum legal landing size. On one date samples were taken from scallops from three separate grounds with contrasting bottom characteristics. At all dates dredge captured scallops had a significantly reduced level of AEC compared to control scallops. This reduction was greatest in February when glycogen levels in the muscle tissue were shown to be at a minimum. There was little or no variability among fishing grounds in the effect of dredge capture on AEC levels. An additional aim of this study was to determine if scallops that encounter dredges but are not captured Suffer a reduction in AEC levels. Scallops collected from dredge tracks immediately following the passage of dredges showed a significant reduction in AEC compared to control, scallops collected front outside the tracks. However, the reduction in AEC was not as great as in captured scallops.