An Investigation into Behavioural Indicators of Stress in Juvenile Scallops

Recessing and righting behaviour requires a big energetic cost to scallops and if the animals are already weakened by the stress of handling, exposure to air and transport they may find if difficult to carry out these manoeuvres. The objectives of this study were to determine the preferred sediment of scallop (Pecten maximus) spat and to determine the recessing and righting behaviour of spat under a dessication stress. The results showed that the time taken to recess was indirectly proportional to the mean sediment size of the sediment. When using the 'preferred' sediment, recessing and righting speed was indirectly proportional to the degree of exposure to air experienced by the animals. Thus by removing seasonal and size variables we were able to demonstrate a clear relationship between quality and behaviour in juvenile scallops. This test is therefore not only sensitive to changes in spat quality but is also a very quick and simple test to perform.