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 Perrin, W. F. 



1969. Using porpoise to catch tuna. World Fishing 18 

 (6):42-45. 



ROYALL, R. M., AND W. G. CUMBERLAND. 



1981. An empirical study of the ratio estimator and esti- 

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 ROYALL, R. M., AND K. R. EBERHARDT. 



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Nancy C. H. Lo 



Southwest Fisheries Center La Jolla Laboratory 

 National Marine Fisheries Service, NOAA 

 La Jolla. CA 92038 



Joseph E. Powers 



Southeast Fisheries Center Miami Laboratory 

 National Marine Fisheries Service, NOAA 

 Miami, FL 331 1*9 



Bruce E. Wahlen 



Southwest Fisheries Center La Jolla Laboratory 

 National Marine Fisheries Service, NOAA 

 La Jolla, CA 92038 



WHITE DALL'S PORPOISE SIGHTED IN 

 THE NORTH PACIFIC 



Several studies on the population and distribu- 

 tion of marine mammals were conducted 

 between 1978 and 1981 in the North Pacific 

 Ocean under a United States-Japan cooperative 

 agreement of the International Convention for 

 the High Seas Fisheries of the North Pacific 

 Ocean. During that period, two white Dall's 

 porpoise, Phocoenoides dalli, were sighted. 



Two of the authors (Joyce and Ogasawara) 

 sighted one such color variant (Fig. 1) at 1410 h 

 (JST) on 29 July 1980, 8 km south of Kushiro, 

 Japan (lat. 42°52. 5'N, long. 144°21.5'E), while 

 aboard the RV Hokushin Maru. The water depth 

 was 70 m and the sea surface temperature was 

 17.5°C. The animal was estimated to be 190 to 



210 cm long and was accompanied by a normally 

 colored Dall's porpoise, dalli type, of the same 

 size. Both animals approached the vessel and 

 rode the bow wave for 5 min. The white animal 

 surfaced once every 5 to 6 s and created a 

 "roostertail" splash, typical of the Dall's 

 porpoise. It was completely white except for a 

 slight gray shading along the dorsal ridge 

 between the dorsal fin and the flukes, and along 

 the posterior edge of the blowhole. There was no 

 color differentiation where the black-white 

 border usually occurs on the lateral surface. 

 Other than color, there were no physical or 

 behavioral characteristics to distinguish this 

 animal from other Dall's porpoise. 



Another white Dall's porpoise was sighted by 

 Rosapepe on 13 August 1980, 25 km west of the 

 Washington State coast (lat. 45°26.5'N, long. 

 124°15.6'W), while aboard the NOAA vessel 

 Miller Freeman. The animal was all white 

 except for a brownish area on the dorsal surface, 

 between the blowhole and the dorsal fin. It was 

 seen with three Dall's porpoises, dalli type, of 

 normal coloration. All four animals approached 

 the vessel and rode the bow wave for 7 min. 



The Dall's porpoise is known to exhibit two and 

 possibly three color variations (Morejohn 1979). 

 The dalli type, the original type described, is 

 mostly black, with a white area on the ventral 

 and lower lateral surfaces, originating in line 

 with the anterior insertion of the dorsal fin and 

 extending posterior of the genital slit (True 

 1885). The truei type is differentiated by the 

 anterior extension of the white area to the 

 anterior insertion of the pectoral flipper 

 (Andrews 1911). The truei type was once 

 classified as a separate species by Andrews 

 (1911) but was later described as a color variant 

 (Cowan 1944). The taxonomic status of this type 

 is still in question. All black Dall's porpoise have 

 been described (Wilke et al. 1953; Nishiwaki 

 1966), as has the gray or striped variant (Wilke et 

 al. 1953; Morejohn et al. 1973). However, the 

 white variant has not previously been described, 

 indicating that this colormorph, possibly caused 

 by albinism, occurs rarely. 



Acknowledgments 



Marine mammal research aboard the Miller 

 Freeman was sponsored by the Platforms of Op- 

 portunity Program, National Marine Mammal 

 Laboratory (NMML), NMFS. U.S. marine 

 mammal studies aboard the Hokushin Maru 



FISHERY BULLETIN: VOL. 80. NO. 2. 1982. 



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