title: Feet, heat and scallops: what is the cost of anthropogenic disturbance in bivalve aquaculture?
abstract: The effects of unnatural disturbances on the behaviour and energetics of animals are an important issue for conservation and commercial animal production. Biologging enables estimation of the energy costs of these disturbances, but not specifically the effect these costs have on growth; a key outcome measure for animal farming enterprises. We looked at how natural and anthropogenically induced activity and energy expenditure of king scallops Pecten maximus varies with temperature. These data were then used to model growth time of king scallops reared in an aquaculture facility under different temperatures and anthropogenic disturbance levels. The scallops exhibited a typical total metabolic rate (MR)-temperature curve, with a peak reached at a middling temperature. The percentage of their total MR associated with spinning and swimming, behavioural responses to disturbance, was considerable. Interestingly, as temperature increased, the activity MR associated with a given level of activity decreased; a hitherto unreported relationship in any species. The model results suggest there is a trade-off in the ambient temperature that should be set by hatcheries between the optimal for scallop growth if completely undisturbed versus mitigating against the energy costs elicited by anthropogenic disturbance. Furthermore, the model indicates that this trade-off is affected by scallop size. Aquaculture facilities typically have controls to limit the impact of human activities, yet the present data indicate that hatcheries may be advised to consider whether more controls could further decrease extraneous scallop behaviours, resulting in enhanced scallop yields and improved financial margins.
authors.affiliation: LabexMER, UMS 3113 CNRS, Institut Universitaire Européen de la Mer, Université de Brest, Rue Dumont D'Urville, 29280 Plouzané, France; Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan.
authors.forename: Anthony A
authors.identifier: 0000-0001-9878-8972
authors.initials: AA
authors.lastname: Robson
authors.affiliation: Centre for Research in Ecology, Department of Life Sciences , University of Roehampton , Holybourne Avenue, London SW15 4JD, UK.
authors.forename: Lewis G
authors.initials: LG
authors.lastname: Halsey
authors.affiliation: Laboratoire des Sciences de L'Environnement Marin (UMR CNRS 6539) , Institut Universitaire Européen de la Mer , Technopôle Brest Iroise, 29280 Plouzané, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Chauvaud
keywords: activity; anthropogenic disturbance; energy expenditure; growth; metabolic rate; temperature