SYSTEMATIC ACCOUNTS 



LARGE CETACEANS (12-26 meters maximum length) 



This section includes seven of the nine baleen whales which occur in 

 the eastern North Pacific and adjacent Arctic waters : the eighth, the 

 minke whale. Balaenoptcra aculorostriita, which reaches only about 10 m 

 maximum length, is listed with the medium-sized whales; the ninth, 

 the bowhead whale, Balama myslicitus. is restricted to the Bering, 



Chukchi, and Beaufort Seas 1. Four of those occur re^ularlv. three rarely 

 it at all in the SCB. The group also includes the two largest toothed 

 whales, the sperm whale. Physctcr macrocephalus. and Baird's beaked 

 whale. Birnrdius hairdii, both of which are found commonly in pelagic 

 waters along and west of the Patton Escarpment and also enter the 

 SCB. 



Residents and Common Migrants 



Eschrichlus rckustus Lill]eborg, 1861 



The gray whale is probably the best known of the great whales of 

 the northeastern Pacific and the species most frequently encountered 

 in and near the CINMS, albeit seasonally. The vast majority of the 

 population spends the winter in subtropical calving/breeding lagoons 

 of mainland Mexico and the west coast of Baja California and summer 

 in arctic and subarctic waters above Unimak Pass, principally the 

 northern Bering and southern Chukchi seas. Migrations betweeen 

 these widely separated "grounds" occur, for the most part, at predict- 

 able times and along well defined routes. 



Although there are a few early migrants and stragglers, the vast 

 majority of southbound migrating gray whales leave the Bering Sea 

 between mid-November and mid-December in components some- 

 what segregated by age-sex class. The southbound movement along the 

 Pacific coast of North America spans the months November through 

 January or early February. Some whales do not complete the south- 

 bound migrations to southern lagoons, electing instead to remain oft 

 British Columbia. Washington. Oregon, or Calilornia. 



^^ 



FlGUR£ z. Nowhere are whales more smgleminded-oi-purpose than south- 

 ward migrating gray whales. In December through February, as singles and in 

 groups of up to 18 individuals, they annually parade through the SCB en 

 route to the lagoons of Baja California and mainland Mexico. A major whale 

 watching industry capitalizes on this highly predictable behavior. (Photo of 

 Santa Barbara by P. C. Howorth.) 



FlGURh J. Migrating gra\- whales pass through areas of natural oil seeps ! topj 

 as well as near oil rigs and other related facilities (bottom). Recent studies 

 indicate that oil on the sea surface and industrial noise from oil exploration 

 and development have significant though shortlived effects on gray whale 

 behavior. (Photos off Anacapa Island. 20 January 1985, by S. Leatherwood. 

 (bottom 1; and off Coal Oil Point. January 1981, by B. S. Stewart; (top).) 



