Other Species Reported 



There are four other species oi great whales m the northeastern 

 Pacific. One, the bowhead whale, Balama mysiiccius Linnaeus, 1758. is an 

 arctic species and a true pagophile, its ecology closelv tuned with the 

 advance and retreat of the arctic icepack. Except for the one e-xcep- 

 tional stranding in Osaka Bay, Japan some years ago. the species is 

 unknown south of the Okhotsk Sea or central Bering Sea, so it is not 

 discussed here. The other three species are not likely to occur in the 

 SCB or CINMS, except perhaps rarely, owing to their more tropical or 

 pelagic distribution or to their current depleted condition m the 

 northeastern Pacific. Therefore, the three are discussed here only 

 briefly. 



near the SCB a year-round source of vagrants tor the waters in and near 

 the CINMS. Even so, we are aware of only two confirmed sightings of 

 this species in the SCB — totaling five animals - both in deep water 

 southwest of San Clemente Island. 



Because of the superficial similarities in appearance benveen fin and 

 sei whales it is possible that some sightings of the latter have been 

 misrecorded as fin whales. However, the absence of confirmed strand- 

 ings from the area by specialists and the dearth of sightings, despite 

 extensive work in the SCB in the past 1 5 years, suggests that sei whales 

 occur in the area only rarely. 



Sei whales, Balainoplcra korealis Lesson, 1828, appear in general to 

 prefer subtropical to cold temperate pelagic regions and to avoid polar 

 and shallow coastal waters. There are three putative stocks in the 

 North Pacific distributed in adjacent areas divided at longitudes 1 5 5 W 

 and I75°W. Prior to exploitation, the size of the aggregate populations 

 was an estimated 42,000 to 82,000 whales. Although a few were killed 

 by shore whalers in the first 40 years of the 20th century, mostly in 

 Alaska, intensive and widespread whaling involving this species did not 

 begin until 1945. Between that year and 1962 nearly 11,000 sei whales 

 were killed in the North Pacific. From 196; through 1974 at least 

 another 4!. 719 were taken in the North Pacific ' including the Bering 

 Sea J. Whaling reduced the populations ot sei whales from an estimated 

 50,000 in 196; to a low of 20,000 in 1974. At present, the populations 

 are thought to be recovering, but there is no reliable estimate of 

 current population size. 



In winter (^December through Marchy eastern North Pacific sei 

 whales are said to be widely but sparsely distributed along and seaward 

 of the continental shelf from at least Piedras Blancas I'ca. 55-50 n) 

 south at least to the Revillagigedos islands and perhaps farther south in 

 the eastern tropical Pacific. At this season, there are apparently only 

 small numbers of sei whales near the westernmost fringes of the SCB. 

 In summer, however, the distribution of sei whales shifts northward 

 and includes waters from about the California/Baja California border 

 throughout the Gulf of Alaska. At this season, ma|or concentrations 

 are reported to assemble "outside the channel islands". Thus, there is 



Figure 16. We know of only two confirmed records of set whales in the SCB 

 (both west of Cortes Banks in September 1977 1, although ma|or concentra- 

 tions have been reported to assemble in summer outside the Channel Islands. 

 The absence of records mav relate to the difficulty in positively distinguish- 

 ing among sei. fin and Bryde's whales. iThoto by F. S. Todd.j 



Bryde's whales. Balamopiera edem Anderson, 1878, also resemble both 

 fin and sei whales. In fact, until recently, even whalers failed to 

 distinguish between sei and Bryde's whales in their records. Therefore, 

 some records of sei whale occurrence may also have been incorrectly 

 logged. Bryde's whales ordinarily occur in warmer waters well west or 

 well south of the SCB. Two forms are thought to exist in the North 

 Pacific — an offshore form found in the warm currents of the south 

 central (to latitude 45 n) and northwestern (to latitude 45 n) Pacific 

 and a smaller inshore form found nearer the coast on both sides of the 

 Pacific. The offshore form does not appear to be distributed, routinely, 

 very far into eastern North Pacific waters. We are aware of only a 

 handful of confirmed sightings near the Continental Shelf of Southern 

 California. All these are from over 200 nm west of the Channel Islands, 

 made during special USNMFS cruises south of latitude 28 N. There is 

 only one confirmed record of Bryde's whales m the SCB, that of a 

 solitary whale photographed off La Jolla in 1954. Despite recent 

 speculation that the species might tend to wander into the SCB more 

 frequently during periods of exceptionally warm waters, there have 

 been no confirmed records for 50 years. 



Bryde's whales are known to have been killed in waters off Mexico 

 in the 1920s and 1950s and may have been involved in other whaling for 

 "fin " whales in which little care was taken to distinguish among similar 

 species. However, in the absence of any hea\'y exploitation the coastal 

 stock in the eastern North Pacific is considered to be "stable at the 

 carrying capacity of its range. " 



Figure 17. Brvde's whales habitually occur well west or south ot the SCB. 

 The only confirmed record near the CINMS is that ot this animal pho- 

 tographed off La Jolla in 1954. (Photo by F. Morc|ohn. from Leachenvood et 

 al., 1982, Figure jga.) 



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