In California, humpbacks use the Farallon Basin as a spring-through-fall feeding ground. The fall migration may begin as early as September for humpbacks in the northern Bering Sea (Berzin and Rovnin, 1966) and as late as December for those in the Gulf of Alaska and California (Fiscus et al., 1976; Dohl, 1983).

Humpbacks are known to winter in three areas: along central Mexico and Baja California; in the Hawaiian Islands; and in the western Pacific around the Mariana, Bonin, and Ryukyu Islands, and Taiwan. Most humpbacks that summer in southeast Alaska and Prince William Sound migrate to wintering areas off Hawaii (Darling and McSweeney, 1983). Whales that summer in central California appear to winter off Baja Mexico (Dohl, 1983; Urban et al., 1987). Photo-identification also indicates that some humpbacks migrate between winter-breeding grounds in Mexico and summering areas in southeast Alaska. During the spring, humpback whales migrate north from overwintering areas to summer areas in the Bering Sea, the Gulf of Alaska, and the Pacific coast of North America. Humpbacks have been sighted as early as March off southeast Alaska, and in May off the Portlock and Albatross Banks, and in Prince William Sound in May. They reach Bristol Bay (Cape Newenham area) in June and enter the Chukchi Sea from July to September (Tomilin, 1957). Breeding and calving occur on the wintering grounds. Most births occur between January and March (Johnson and Wolman, 1984).

Humpbacks feed on crustaceans such as euphausiids, amphipods, mysids, and small schooling fish including Pacific herring, capelin, anchovies, sardines, cod, and sand lance (Tomilin, 1957; Wolman, 1978; Wing and Krieger, 1983). They are thought to feed mainly during the summer period, because stomachs examined during the winter months in coastal or subtropical waters of both hemispheres are generally empty (Wolman, 1978). Feeding occurs at the surface or in the midwater regime. Humpbacks capture food items by engulfing their prey or by laterally feeding at the surface.

RIGHT WHALE: In the eastern Pacific Ocean, right whales occur from Alaska and the Aleutian Islands south to Oregon and California (Tomilin, 1957). Right whales were hunted nearly to extinction by commercial whalers during the 1800's; despite protection, the population has yet to show any signs of recovery. Over the past 30 years, 32 to 36 right whales have been sighted in the central North Pacific-Bering Sea, and 21 to 26 on the west coast of North America south of Kodiak, Alaska. The current size of the North Pacific population is unknown. Due to limited sighting information, no reliable estimate is possible; however, the sighting records suggest that there are probably only a few hundred individuals remaining.

Historic whaling records indicate that right whales were taken from April through September in the Gulf of Alaska, and from August through September in the Bering Sea/Bristol Bay area. Between spring and fall (April-September), right whales are generally found north of 50° N. latitude, particularly in the Gulf of Alaska, and roughly between 145° W. to 151° W. longitudes (Berzin and Rovnin, 1966). When in the Bering Sea, the whales are likely to be found in an area bounded by Atka, St. Matthew, and Nunivak Islands (Berzin and Rovnin, 1966).

The migration routes and winter distribution of the right whale population is unknown and subject to speculation. After examining virtually all available sighting data, Scarff (1986) hypothesized that right whales summering in the eastern North Pacific mate, calve, and overwinter in the mid-Pacific or western North Pacific. A few individuals overwinter off the Pacific coast of North America. Right whales do feed primarily on calanoid copepods, and secondarily on euphausiids, which they skim from the upper portions of the water column.

BLUE WHALE: The most recent estimate of the North Pacific blue whale population is about 1,600 individuals (USDOC, NOAA, NMFS, 1991); however, there has been little new information on blue whale abundance since hunting ceased in 1967. It is estimated that prior to exploitation by commercial whaling there were about 4,900 blue whales in the North Pacific. There have been numerous sightings in the last several years off Mexico and California, but no useful census data are available for population assessment. There is no evidence that the blue whale stocks in the North Pacific are recovering, given the following factors: the relative scarcity of blue whales based on opportunistic sightings; the low population estimates relative to their initial abundance; and the low intrinsic rate of increase noted for this and other baleen whale populations, to date (Mizroch, Rice, and Breiwick, 1984b).

Summering blue whales are present from the waters off California to Alaska. In southern California, Dohl et al. (1978) observed a total of 83 animals in 29 sightings. Thirty-five percent of the animals were recorded in the spring quarter (April, May, June), 49 percent in the summer quarter, and 16 percent in the fall quarter. No animals were sighted during the winter. The greatest number of sighted blue whales traversed the outer edge of the Southern California Bight between the Santa Rosa-Cortes Ridge and Tanner-Cortes Banks, especially between July and October. They also were frequently sighted in waters near the southern California Channel Islands during the same months, occasionally within 28 km of the mainland.

The blue whale is a common summer/autumn visitor to central and northern California although in some years, whales may arrive as early as May and remain until mid-December. During 1980 to 1983 in northern and central California, most blue whale sightings occurred in waters over the continental shelf and slope (45-999 fathoms); all but one of the 66 animals were south of Fort Bragg (Dohl, 1984). Blue whales also have been seen "far off the coast of northern California... At least some of their movements, then must occur along pelagic routes" (Leatherwood et al., 1982). Blue whales are most commonly sighted off the Oregon coast from May through June and August through October (Rice, 1974).

Modern whaling data indicate that blue whale abundance peaks in the eastern Gulf of Alaska in July and near the eastern Aleutian Islands in June (Rice, 1974). Compared to other large cetaceans, the blue whale migration is more limited in northern waters. Marking studies revealed little apparent movement of blue whales while they were on their feeding grounds (Morris, Alton, and Braham, 1983). The species occur in relative abundance in a narrow area just south of the Aleutian Islands from 160° W. to 175° W. longitude (Berzin and Rovnin, 1966; Rice, 1974). The species is also distributed in an area north of 50° N. latitude, extending from southeastern Kodiak Island across the Gulf of Alaska, and from southeast Alaska to Vancouver Island (Berzin and Rovnin, 1966). According to whaling records, large concentrations of this species once occurred in two areas: (1) the northern part of the Gulf of Alaska southwest of Prince William Sound in the Portlock Banks area (Nishiwaki, 1966), and (2) to a lesser extent, in an area west of the Queen Charlotte Islands and southeast Alaska (Berzin and Rovnin, 1966). Recent blue whale sightings in Alaskan waters have been scant. Blue whales usually begin to migrate south out of the Gulf of Alaska by September (Berzin and Rovnin, 1966). Migration routes are thought to be along the western coast of North America. The North Pacific blue whale population winters from the "open waters of the midtemperate Pacific south at least to 20° N. latitude." Blue whales occur up to 1,300 to 2,800 km offshore Central America and at least as far south as Panama (Leatherwood et al., 1982).

According to Berzin and Rovnin (1966), the northward spring migration of the North Pacific population begins in April through May, with whales traveling along the American shore of the Pacific. Blue whales are sighted off Baja California and the Mexican mainland in February, with peak densities apparently occurring in April.

Mating and calving are believed to take place over a 5-month period during the winter (Mizroch, Rice, and Breiwick, 1984b).

On their summer range, the principal food of blue whales is small euphausiid crustaceans (Euphausia pacifica and Thysanoessa spinifera) (Nemoto, 1959; Berzin and Rovnin, 1966) which they obtain by engulfment.

SEI WHALE: The most recent estimate of the North Pacific sei whale population is 9,100 individuals. The pre-exploitation population estimate for sei whales is 40,000 individuals (USDOC, NOAA, NMFS, 1991). Commercial whaling catches of sei whales in the North Pacific and Bering Sea rose sharply during the 1960's and then dropped sharply thereafter. Despite protection from commercial whaling, there are no indications of population trends for this species.

Sei whales are more common in pelagic temperate waters and only occasionally venture into the Bering Sea. They apparently migrate to lower latitudes in winter and to higher latitudes in summer. Sei whales have been reported in the Gulf of Alaska and along the Aleutian Chain during the summer (Wada, 1981), with most found south of the Aleutians and off the eastern Kamchatka Peninsula to the Commander Islands (Nasu, 1963).

The southward migration begins in August or September. During late summer and early fall, sei whales are usually present in considerable numbers off central California. During January through March, most are found between 20° N. and 23° N. latitudes, but they range from Point Piedras Blancas, California (35° N. latitude), to the Revillagigedo Islands off Baja California (18° N. latitude).

Sei whales breed and calve in the warmer waters of their winter range. Most breeding occurs from October to March, with a peak in late December; calving occurs from September to February, with a peak in November (Masaki, 1976).

Sei whales feed while skimming surface waters and generally do not dive deeply. Kawamura (1980) summarized the foods of approximately 12,000 sei whales collected in the North Pacific and found that copepods comprised 83 percent of the diet, followed by euphausiids (13%), fish (3%), and squid (1%).

SPERM WHALE: The number of sperm whale individuals in the North Pacific population large enough to be commercially exploitable (males aged 11 years and older and females aged 10 and over) has been estimated at around 930,000 (USDOC, NOAA, NMFS, 1991). This is in comparison to an estimated initial population size of 1,260,000. Commercial whaling took many sperm whales. On average, over 20,000 sperm whales were taken worldwide annually between 1956 and 1976.

In the eastern North Pacific, sperm whales range from the equator occasionally north to 62° N. latitude and west to Cape Navarin in the Bering Sea. Sperm whales generally are found in waters of 200 m or deeper, and typically only males venture north of 50° N. latitude. Sperm whales migrate poleward in spring and summer, returning to the temperate and tropical portions of their range in the fall.

During the summer months, male sperm whales are present in the Bering Sea, where they are generally encountered singly or in pairs. Summer feeding grounds occur off British Columbia, the Gulf of Alaska, the Alaska Peninsula, and the Aleutian Islands. In the Bering Sea, sperm whales most commonly occur along the shelf break between the Pribilof Islands and Cape Navarin. Ohsumi (1965) and Best (1975) estimated that 40 to 60 percent of the mature males (20% to 30% of the entire mature population) spend the summer months at high latitudes (the Bering Sea and Aleutian Islands areas). Fall migrations begin in September, and most whales have left Alaskan waters by December.

Off central and northern California, sperm whales are present year-round in offshore waters. Peak abundance has been observed during May through June, and August through November as the whales migrate through the area (Gosho, Rice, and Breiwick, 1984). The wintering grounds are generally south of 35° N. latitude, between the Hawaiian Islands and California. Migration northward to Alaskan waters begins in March and continues through May (Berzin and Rovnin, 1966).

Breeding occurs during the spring and early summer (April through August). Calves are born after a gestation period of about 15 months (Gosho, Rice, and Breiwick, 1984). Sperm whales feed predominantly on squid and fish, on the bottom as well as in midwater regions.

(b) Pinnipeds

STELLER SEA LION: Steller (northern) sea lions occur over the continental shelf throughout the Bering Sea and Gulf of Alaska, south to San Miguel Island in southern California (Burns, Frost, and Lowry, 1985). The total Steller sea lion population is estimated to be well under 100,000 and declining precipitously, especially in the area from the central Aleutian Islands to the Kenai Peninsula, where a decline of 82 percent since 1960 and 63 percent since 1985 has occurred (Brahman, Everitt, and Rugh, 1980; Loughlin, pers. comm., 1989; Loughlin, Rugh, and Fiscus, 1984; Merrick, Loughlin, and Calkins, 1987). The population in the eastern Gulf of Alaska (Kenai Peninsula east to Cape St. Elias) began to decline sometime after 1980, although the population in southeast Alaska appears to be stable (USDOC, NOAA, NMFS, 1992). The Steller sea lion has been listed as a threatened species by the NMFS (55FR12645, April 5, 1990). As part of its emergency listing of the sea lion, the NMFS established protective buffer zones around principal rookeries. In August 1993, the NMFS published the Final Rule designating critical habitat (major rookeries and haulouts and aquatic zones around them) for Steller sea lions (58FR45269, August 27, 1993).

Sea lion rookeries in Alaska are located on the Pribilof Islands, on Amak Island north of the Alaska Peninsula, throughout the Aleutian Islands and western Gulf of Alaska to Prince William Sound, and on Forrester Island, White Sisters, and Hazy Island in southeast Alaska. Haulouts are numerous throughout the breeding range and some are used in the northern Bering Sea as well. Sea lions disperse extensively throughout their Alaskan range following the breeding season (Burns, Frost, and Lowry, 1985). Descriptions of the Steller sea lion contained in USDOI, MMS (1990a), Gulf of Alaska/Cook Inlet Sale 88 FEIS (USDOI, MMS, 1984a), St. George Basin Sale 89 FEIS (USDOI, MMS, 1985c), 55FR12645 April 5, 1990, 58FR45269, August 27, 1993, and Cook Inlet Planning Area Oil and Gas Lease Sale 149 DEIS (USDOI, MMS, 1995) provide additional information on this species.

There are several nonendangered cetaceans within the Alaska Region. They include beluga, minke, and killer whales, and the harbor porpoise. The description of the killer whale and the harbor porpoise can be found in Section III.C.2.a.

The beluga whale, a subarctic and arctic species, who's populations in Alaska are distributed in marine waters from Yakutat in the Gulf of Alaska to the eastern Beaufort Sea in Canada, numbers in excess of 25,000 whales

in Alaskan waters (Frost, Lowry, and Burns, 1988). A separate population is centered in Cook Inlet at about 1,300 whales (Calkins, 1989).

Major concentrations occur in Bristol Bay (1,000-1,500 whales); Yukon River-Norton Sound (1,000-2,000 whales); Kotzebue Sound (500-2,000); waters in and adjacent to Kasegaluk Lagoon (1,500-2,500 whales); and the Mackenzie River Delta, eastern Beaufort Sea, and Amundsen Gulf (11,500). The Bering-Chukchi-Beaufort population may be in excess of 25,000, while an estimated 11,500 beluga whales migrate from the Bering Sea to the eastern Beaufort Sea (Frost, Lowry, and Burns, 1988). Most of the latter population migrate into the Beaufort Sea in April or May. However, some whales may pass Point Barrow as early as late March and as late as July. The spring-migration routes through ice leads are similar to those of the bowhead whale. A major portion of the Beaufort Sea seasonal population concentrates in the Mackenzie River estuary during July and August. An estimated 2,500 to 3,000 belugas summer in the northwestern Beaufort and Chukchi Seas, with some using coastal areas such as Peard Bay and Kasegaluk Lagoon. Beluga whales feed on a variety of fish, shrimp, squid, and octopus (Burns et al., 1985b). Calving takes place during the summer, June to July, at lower latitudes and July to August in the Arctic (Calkins, 1989; and Lowry 1984).

Fall migration through the western Beaufort Sea is in September or October. Although small numbers of whales have been observed migrating along the coast, surveys of fall distribution strongly indicate that most belugas migrate offshore along the pack-ice front. Beluga whales are an important subsistence resource of Inuit Natives in Canada and also are important locally to Inupiat Natives in Alaska.

The minke whale (Balaenoptera acutorostrata), the smallest of the baleen whales, ranges worldwide in waters along the continental margins (Green et al., 1991). The world population of minke whales is currently estimated at about 725,000 animals, of which 600,000 are in the southern hemisphere (Brownell, Ralls, and Perrin, 1989). No reliable estimates exist for the eastern North Pacific population (Stewart and Leatherwood, 1985), although population estimates for the western North Pacific range from 9,000 to 13,500 (Wada, 1976; USDOC, NOAA, 1987).

Although minke whales have been hunted in the northern hemisphere for much of the last 50 years, large-scale commercial exploitation of the species in the Antarctic did not begin until the early 1970's and ended after Japan's 1986 to 1987 season (Brownell, Ralls, and Perrin, 1989). In 1988, Japan began research catches of about 300 whales per year in the Antarctic. Minke whales have never been hunted commercially in the eastern North Pacific (Barlow, 1994), although they are occasionally taken by American Eskimos for subsistence purposes (Stewart and Leatherwood, 1985). Brownell, Ralls, and Perrin (1989) reported that no minke whales were taken in the North Pacific in 1988.

In the eastern North Pacific, minke whales are a coastal species, usually occurring within the 200-m depth contour (Tomilin, 1957; Consiglieri and Braham, 1982), and are widely distributed on the continental shelf throughout the eastern North Pacific (Green et al., 1989). In the summer, minke whales appear to be broadly distributed between Baja California and the Bering and Chukchi Seas; in the winter, their range is more compressed, extending from Islas De Revillagigedo, Mexico, to at least northern Washington (Rice, 1974; Leatherwood et al., 1982). Some individual minke whales apparently establish home ranges in inland

Washington waters and off central California, (Dorsey et al., 1990). In northern latitudes with high food concentrations during spring and summer, they occasionally congregate in groups (Leatherwood et al., 1982).