Fig. 1. Relationship between shark white muscle enzyme activity [µmol substrate converted to product per min (IU) per g wet mass of tissue] at 20°C and body mass. (A) Citrate synthase (CS) activity in blue (open circles), scalloped hammerhead (open triangles), leopard (open squares), common thresher (shaded triangles), mako (shaded circles) and salmon (shaded squares) sharks. In cases where the correlation between enzyme activity and mass was significant for a species, a linear regression was fit to the data. For the mako, IU g^-1=2.78–0.53x[log₁₀(mass)], r=-0.44, P=0.01, N=31; for the scalloped hammerhead IU g^-1=1.17+1.53x[log₁₀(mass)], r=0.72, P=0.01, N=10. (B) Lactate dehydrogenase (LDH) activity for the same species as for CS and two additional shark species: the Atlantic blacknose (open diamonds) and Atlantic sharpnose (open inverted triangles).