Pilot Whale 

 Glohkephala c. f. G. macrorhynchus Gray, 1846 



Pilot whales, also known as potheads - because of che bulbous 

 forehead - and blackfish - because of the largely black coloration - 

 are well known because they have been exploited in local fisheries in 

 widespread locations for many years, they have had a long and 

 successful history in aquarium displays and shows, and they tend to 

 concentrate, at least seasonally, on important fishing grounds, particu- 

 larly those for squid. The common name most often used for the 

 species derives, in fact, from the frequent common occurrence of 

 whales and fishermen on fishing grounds and the resulting, often 

 quoted, misperception that the whales "piloted" the fishermen to the 

 location. Pilot whales are particularly well known in the SCB as they 

 are often seen on squid grounds off the heavily populated Los Angeles 

 coastline and on the popular trips between coastal cities and the 

 Channel Islands, particularly Santa Catalina and the northern islands. 



There is continuing confusion about the ta.xonomic status of pilot 

 whales in the northeastern Pacific, as elsewhere. It has been postulated 

 that there may be three forms in the North Pacific overall and that at 

 least two of them — Clohicephala macrorhynchus and G. scammotiit — occur 

 in eastern waters. However, conclusive definition of pilot whale tax- 

 onomy in this area must await systematic review of specimens and data. 



Whatever their affinities, pilot whales are present, but not at all 

 common, in the Gulf of Alaska and south along the coasts of 

 Washington, Oregon and Northern California. Shortfin pilot whales, 

 the form we believe to be dominant in the SCB, appear to prefer warm 

 temperate climates, and their movements north of about latitude 40 N 

 are thought to relate to incursions of warm water. Pilot whales are 

 abundant, at least locally, from the latitude of Point Conception at 

 least as far south as the waters off Guatemala, and are found through- 

 out the tropical eastern Pacific, including waters around Hawaii and 

 other pelagic islands. 



The Southern California and northern Baja California population 

 appears to have two components. Some individuals are known to stay 

 year-round in the vicintity of the California Channel Islands and some 

 of the Baja coastal islands, showing a marked affinit\' for the coastal 

 heads of deep submarine canyons. Others arc seen much of the year in 



Figure 11. Pilot u h.ilc herds often hunt in "'chorus lines", swimming side h\ 

 side until one animal detects food then breaking ranks to feed individually. 

 Photo irom Santa Barbara Island. .April 1977 by S. Leathenvood. J 



deeper waters far offshore. In late winter-early spring, when squid 

 invade inshore waters to spawn, some of these offshore animals appear 

 to move inshore, joining "residents to form larger concentrations over 

 the most active squid spawning grounds. In summer and autumn, the 

 offshore animals abandon the inshore areas, apparently returning to 

 pelagic waters. 



Pilot whales have been reported from the Santa Barbara Channel 

 and waters of the CINMS in all quarters. However, here as elsewhere, 

 numbers appear to peak in winter and spring. Though they may be 

 .seen in any part of Santa Barbara Channel pilot whales are most often 

 encountered near Mugu and Hueneme canyons, in the Anacapa-Santa 

 Cruz Channel, along the south shores of Santa Cruz and Santa Rosa 

 islands, and west of San Miguel Island. Recent studies indicate that 

 pods may maintain the same membership over long periods. Data from 

 the 1960s and 1970s suggest that the same pods and individuals return 

 to the same areas year after year. Intense El Niiio conditions inter- 

 rupted long standing patterns in the SCB in the early 1980s, during 

 which time pilot whales were virtually absent from many traditionally 

 important areas. But pilot whales have recently begun to return to such 

 areas presumably as effects of the brief warming trend wane. 



Figure 21. The pilot whale population m the b*^.n mcludcs residents , seen 

 throughout the year and rcsighted year after year, and "migrants" which 

 invade the SCB annually during the peak of the squid season. (Photo north 

 of San Nicolas Island, April 1974, by B. S. Stewart.) 



Figure i^. Pilot whale strandmgs .ire not uncommon, on the mainland or 

 the Channel Islands. fPhoto from Cuyler Harbor, San Miguel Island, 11 

 September 1984 bv D. Seagars.) 



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