. The Canadian field-naturalist. 58 The Canadian Field-Naturalist Vol. 106. Figure 2. Shaded areas indicate approximate regions where Delphinus delphis has been reliably recorded. Strays will occur outside these areas, especially in warmer waters, and there may be other areas of concentration. Much material from the tropics has been inaccurately identified in the older literature and the records are unreliable. Tomilin (1967) likewise considered Delphinus del- phis of the Black Sea to be a unit population. Eastern North Pacific Watson (1981) and Gaskin (1985) illustrated the whole of the tropi
. The Canadian field-naturalist. 58 The Canadian Field-Naturalist Vol. 106. Figure 2. Shaded areas indicate approximate regions where Delphinus delphis has been reliably recorded. Strays will occur outside these areas, especially in warmer waters, and there may be other areas of concentration. Much material from the tropics has been inaccurately identified in the older literature and the records are unreliable. Tomilin (1967) likewise considered Delphinus del- phis of the Black Sea to be a unit population. Eastern North Pacific Watson (1981) and Gaskin (1985) illustrated the whole of the tropical and subtropical Pacific as inhabited by this species, but it is unlikely that the species is resident throughout this region, although schools may transit through virtually any area at some time or other. Probably the majority of all pop- ulations is concentrated along the coastal shelves, perhaps seasonally spilling out along convergence zones, if abundant prey are present. The truly pelagic ocean regions are more the domain of the spotted and spinner dolphins of the genus Stenella, rather than Delphinus. The northern limital record on the west coast of North America is a stranding at Victoria, British Columbia (Leatherwood et al. 1982), but these authors pointed out that few sightings are made north of Point Conception, California. Scheffer and Slip (1948) included it in their list of cetaceans of Washington State on the basis of a photograph and a specimen of dubious identity recorded from Pacific Beach. Evans (1976) summarized data from tuna boat observers and research cruises and showed that the confirmed regular range covered a broad belt up to 600 nautical miles offshore from about 36°N to about 5°S in the vicinity of the Galapagos Islands. Evans recognized a clear break in distribution of Delphinus delphis extending for several hundred miles along the coast of Mexico in the vicinity of Acapulco, providing more evidence for north-south population segregation, possi
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