The effects of pop-up satellite archival tags (PSATs) on the metabolic rate and swimming kinematics of juvenile sandbar shark Carcharhinus plumbeus

Abstract

Pop-up satellite archival tags (PSATs) have been used since the 1990s to document the movements and post-release survival of numerous fish species. The effects of PSAT attachment on metabolic rate, cost of transport, and swimming kinematics have, however, not been broadly investigated. We therefore quantified the acute effects of PSAT attachment on these parameters in juvenile (47–87cm fork length) sandbar shark Carcharhinus plumbeus. Using a water tunnel, we also measured the lift and drag forces of PSATs from three manufacturers which allowed us to calculate the theoretical power costs of towing these devices. We found no evidence that PSAT attachment results in increases in metabolic rate or cost of transport, or influences swimming kinematics of juvenile sandbar shark at volitional swimming speeds. Applying drag force measurements obtained for PSATs to our data showed that the predicted fractional increase in metabolic rate engendered by towing one of these devices at a specified velocity, normalized by the metabolic rate when swimming at that velocity minus the standard metabolic rate, would be below 5%. Our results are therefore congruent and suggest that PSAT attachment does not negatively impact juvenile sandbar shark (and by extension other elasmobranch species of equivalent or larger body sizes and employing a similar swimming mode).