title: Animal physiology. Whole-body endothermy in a mesopelagic fish, the opah, Lampris guttatus.
abstract: Endothermy (the metabolic production and retention of heat to warm body temperature above ambient) enhances physiological function, and whole-body endothermy generally sets mammals and birds apart from other animals. Here, we describe a whole-body form of endothermy in a fish, the opah (Lampris guttatus), that produces heat through the constant "flapping" of wing-like pectoral fins and minimizes heat loss through a series of counter-current heat exchangers within its gills. Unlike other fish, opah distribute warmed blood throughout the body, including to the heart, enhancing physiological performance and buffering internal organ function while foraging in the cold, nutrient-rich waters below the ocean thermocline.
authors.affiliation: Fisheries Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), La Jolla, CA 92037, USA. nick.wegner@noaa.gov.
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Wegner
authors.affiliation: Ocean Associates, Southwest Fisheries Science Center, NMFS, NOAA, La Jolla, CA 92037, USA.
authors.forename: Owyn E
authors.initials: OE
authors.lastname: Snodgrass
authors.affiliation: Fisheries Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), La Jolla, CA 92037, USA.
authors.forename: Heidi
authors.initials: H
authors.lastname: Dewar
authors.affiliation: Fisheries Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), La Jolla, CA 92037, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Hyde
mesh_terms: D058500:Animal Fins / Q000502:physiology*; D000818:Animals; D005075:Biological Evolution; D001831:Body Temperature; D003080:Cold Temperature; D005399:Fishes / Q000033:anatomy & histology / Q000097:blood / Q000502:physiology*; D005880:Gills / Q000502:physiology*; D006321:Heart / Q000502:physiology; D009038:Motion; D022722:Thermogenesis; D014781:Viscera