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Visual track census and a new method, acoustic counting, were used to estimate the humpback whale (Megaptera novaeangliae) population in the West Indies. Results produced by the two methods differed to some extent. The average or best estimate was 1018 whales with a range of 785–1157. Silver and Navidad banks, containing approximately 85% of the total population, are presently the major nursery grounds in the West Indies. The humpback whale population in the western North Atlantic has increased since the early part of the century.

Adenyl cyclase activity was measured by conversion of [32P]ATP to adenosine 3′:5′‐cyclic [32P]phosphate in a washed particle suspension from mouse and rat liver. The test contained an ATP regenerating system and 10 mM unlabeled Ado‐3′:5′‐P to trap the labeled Ado‐3′:5′‐P formed. Decreased activities were observed when methyl xanthines were used in place of unlabeled Ado‐3′:5′‐P. The reaction was stimulated by Mg++ which increased Vmax without changing the apparent Km towards ATP. Adenyl cyclase activity was stimulated by synthetic glucagon over the range of 0.1–20 μg/ml. Removal of Ca++ by ethylene glycol‐bis‐(β‐amino‐ethyl ether)‐N,N'‐tetraacetic acid (EGTA) strongly augmented glucagon action, while 1 mM Ca++ was inhibitory. The data suggest enhanced transmission of the hormone signal from the (hypothetical) receptor to the catalytic enzyme unit by chelation of membrane bound calcium. In contrast to the hyperbolic dose response curve observed with glucagon, the curve with fluoride (1–10 mM) was sigmoidal in shape, the effect being inhibited by 1 mM pyrophosphate. Although inhibition by Ca++ was observed, EGTA did not augment the effect of fluoride. The effects of fluoride and glucagon at maximal concentrations were not additive, indicating stimulation of the same adenyl cyclase system.

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