Dall’s porpoises are common in many parts of the North Pacific, and density is high in many areas of the range. The total abundance of the species is probably over 1.2 million individuals (Buckland et al. 1993). In Alaska, the abundance is estimated at 83,400 (CV=10%) (Angliss and Outlaw 2005). Along the U.S. west coast, abundance estimates have ranged from about 35,000 to 134,000, averaging 86,000 animals (CV = 45%) between 1991 and 2005 (Barlow and Forney, in press). In the western North Pacific, the truei-type population migrating between the Pacific coasts of Japan and the central Okhotsk Sea is estimated at 217,000 (CV=0.23). The dalli-type population migrating between the Sea of Japan and the southern Okhotsk Sea is estimated at 226,000 (CV=0.15), and the dalli-type population summering in the northern Okhotsk Sea at 111,000 (CV=0.29) (IWC 1998). These estimates are subject to biases due to response to survey vessels.

The International Whaling Commission currently recognizes 11 populations of this species, based on differences in genetics, pollutant loads, parasite faunas, and distribution patterns of cow/calf pairs (IWC 2002). Three of them summer in the Okhotsk Sea, two in the Bering Sea, four in the North Pacific, and two off the US coast, but the wintering grounds are unknown for many of them. The populations cannot be reliably distinguished by their external appearance at sea except for the three summering in the Okhotsk Sea, which are distinguishable based on the pigmentation and location.

Unknown