COLOR PATTERNS OF SPINNER PORPOISES 



(STENELLA CF. S. LONGIROSTRIS) OF THE EASTERN PACIFIC 



AND HAWAII, WITH COMMENTS ON DELPHINID PIGMENTATION 



William F. Perrin' 



ABSTRACT 



In this paper, the second of a series on the morphology of small pelagic delphinids by 

 the author, the color patterns of forms of a tropical spinner porpoise Stenella cf. S. long- 

 irostris (Gray) 1828 from the far eastern Pacific, from the waters between North America 

 and Hawaii, and from Hawaiian waters are described and illustrated. The patterns 

 can be analyzed in terms of discrete component systems, and most geographical variation 

 appears to be in a "dorsal field system" overlying a basic general pattern. The overlay 

 is darkest and most extensive in the easternmost form considered and lightest and least 

 extensive in the Hawaiian form. The color patterns of three other delphinids, Stenella 

 graffmani, Delphinus sp., and Tursiops truncatus are analyzed with the component ap- 

 proach, and possible pattern element homologies are defined. 



During the course of collecting materials and 

 data for population studies of porpoises involved 

 in the seine fishery for tunas in the eastern trop- 

 ical Pacific (Perrin, 1970a), I have during the 

 last several years had the opportunity to observe 

 and, less often, to photograph the color patterns 

 of a large number of small pelagic delphinids of 

 several species. Emerging patterns of variation 

 and their possible implications for the systemat- 

 ics of these very poorly known mammals have 

 prompted me to undertake detailed analyses of 

 this body of observations. I have previously 

 (Perrin, 1970b) described the color pattern of 

 the eastern Pacific spotted porpoise Stenella 

 graffmani (Lonnberg) 1934. The primary pur- 

 pose of this paper is to describe the ontogeny 

 and geographical variation of the color patterns 

 of spinner porpoises of the eastern tropical Pa- 

 cific and Hawaii. Some description is included 



' National Oceanic and Atmospheric Administration, 

 National Marine Fisheries Service, Southwest Fisheries 

 Center, La Jolla. CA 92037. 



also of variation in the shape of the dorsal fin 

 and correlated features. 



The study is based on observations on 157 

 specimens from the eastern Pacific (Figure 1), 

 of which 41 were photographed, and on photo- 

 graphs and observations of approximately 35 

 wild and captive animals from Hawaiian waters. 

 Many of the specimens, including most of those 

 from the far eastern Pacific east of Clipperton 

 Island, were examined minutes after capture; 

 others were examined after being held in frozen 

 storage for up to 8 months. Degree of sexual 

 development was determined by histological ex- 

 amination of gonads, with the exception of the 

 large male (Figure 8) from Acapulco, of which 

 only a photograph is available and which was 

 undoubtedly a mature male. Skeletons of spe- 

 cimens of many of the animals illustrated were 

 placed in museums, and the museum numbers are 

 given in the figure captions. 



The spinner porpoise of the far eastern Pa- 

 cific has been referred to Stenella microps 

 (Gray) 1846 (Miller and Kellogg, 1955; Hester, 



Manuscript accepted March 1972. 



FISHERY BULLETIN: VOL. 70. NO. 3, 1972. 



983 



