title: Establishing the thermal window for aerobic scope in New Zealand geoduck clams (Panopea zelandica).
abstract: Geoduck clams (Panopea spp.) are the longest-lived and largest deep burrowing bivalve. Their unique morphology allows them to live buried in the sediment at depths of up to 1 m. The endemic New Zealand geoduck (Panopea zelandica Quoy and Gaimard, 1835) has recently been identified as a potential species for aquaculture. However, very little is known about the biology and physiology of this entirely subtidal geoduck species. Currently, the New Zealand geoduck fishery relies entirely upon wild harvests, but farms are expected to emerge as cultivation protocols are established. A key step in the optimization of cultivation procedures is the identification of optimal temperature and food rations. One method for establishing thermal optima is to identify the temperature window that supports the widest aerobic scope: the degree to which metabolic rate can be increased to support elevated activity demands. Thus, we investigated the aerobic scope for activity at five different temperatures representative of typical environmental conditions (8, 11, 15, 19, and 23 °C) for juvenile and young adult P. zelandica. Clearance rate was also measured at all temperatures. Comparisons of aerobic scope for activity and clearance rates between size classes revealed that juvenile geoducks had a narrower thermal optimum than young adults (15-19 versus 11-19 °C, respectively). Temperatures higher than 19 °C resulted in a reduction of aerobic scope for activity and clearance rate for both juvenile and young adults, which may lead to reduced performance and elevated mortality. These findings provide the first measures of aerobic scope in P. zelandica, a key step towards a meaningful understanding of the ecophysiology of this unusual species.
authors.affiliation: Institute for Applied Ecology New Zealand, School of Sciences, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand.|Center of Aquaculture Biotechnology, Research Institute for Aquaculture No.1, Bac Ninh, Vietnam.
authors.forename: Dung V
authors.initials: DV
authors.lastname: Le
authors.affiliation: Institute for Applied Ecology New Zealand, School of Sciences, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland, 1142, New Zealand. andrea.alfaro@aut.ac.nz.
authors.forename: Andrea C
authors.initials: AC
authors.lastname: Alfaro
authors.affiliation: Cawthron Institute, Nelson, New Zealand.
authors.forename: Norman L C
authors.initials: NL
authors.lastname: Ragg
authors.affiliation: Cawthron Institute, Nelson, New Zealand.
authors.forename: Zoë
authors.initials: Z
authors.lastname: Hilton
authors.affiliation: Cawthron Institute, Nelson, New Zealand.
authors.forename: Nick
authors.initials: N
authors.lastname: King
mesh_terms: D000064:Acclimatization; D000332:Aerobiosis; D000818:Animals; D049872:Bivalvia / Q000502:physiology*; D004734:Energy Metabolism; D005247:Feeding Behavior; D058086:Microalgae; D009520:New Zealand; D010101:Oxygen Consumption; D013696:Temperature
keywords: Aerobic scope; Clearance rate; Metabolic rate; New Zealand geoduck; Panopea zelandica; Temperature