Body temperature of the salmon shark, Lamna ditropis

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The salmon shark, Lamna ditropis Hubbs and Follett, is a streamlined, pelagic predator capable of rapid swimming locomotion, very similar to its close relative, the Atlantic porbeagle, Lamna nasus (Bonnaterre). The porbeagle is warm-bodied, maintaining deep body temperatures 7–11 °C above those of the surface water from which they are captured (Carey & Teal, 1969a). Presumably, Lamna ditropis is also warm-bodied. Opportunities to measure temperatures of salmon sharks occurred on 2, 4 and 5 September 1979, when one of us (D.R.) hooked and landed three salmon sharks while hand-trolling for salmon. The sharks were all caught near Cape Edgecumbe, about 60 km from Sitka, Alaska (57° 6´N, 135° 55´ W) at a depth of 12–40 m.