Environmental Physiology of Lionfish (Pterois volitans and Pterois miles) Metabolic Systems: Are There Physiological Limits to Inshore Invasion?

The invasive Indo-Pacific lionfish ( Pterois sp.) is now well established in the western Atlantic and is broadly considered a significant threat to native fish populations and overall biodiversity as a result of its rapid geographic range expansion, fast individual growth, high fecundity, and high predation rates. This study examines the energetic physiology of lionfish via aerobic-metabolic scope under the influence of various temperature-hypoxia regimes using stop-flow respirometry to determine current and future invasion success into inshore temperate estuaries. Thirty lionfish were captured off southeast Florida and allowed a minimum of a two-week acclimation period prior to experimental trials. To determine relative hypoxia tolerances, lionfish metabolic scopes were observed under normoxic conditions and subsequently subjected to nine stepwise decreases in oxygen saturation of 10% to determine critical oxygen saturation (Scrit) values at four different temperatures. Lionfish aerobic scopes at 25℃ and 30℃ were observed to be 99 mg O ₂ /kg/h and 111 mg O ₂ /kg/h, respectively. Furthermore, lionfish exhibited a mean S _crit value of 23.8 ±2% at 25℃. Additional trials wereconducted to determine how influences of both mild and severe hypoxia limited metabolic scope under the respective temperatures. Data from this study will be incorporated into ecophysiological models to effectively determine current impacts of lionfish on sensitive ecosystems as well as forecast future impacts in light of concurring global temperature increases. Mechanistic physiological models from this study will directly enhance fisheries management agencies efforts to mitigate impacts from lionfish on commercially and ecologically important species thereby improving the integrity of sensitive ecosystems.