Humpback Whales in Glacier Bay National Monument, Alaska Part 7

2. distribution, size and species composition of fish catch--in and outside the Bay

3. distribution, abundance and movements of competing and predatory species

C. Experiments to validate hypothesis concerning possible effects of various stimuli on whales--representative stimuli, representative whales (age, s.e.x), representative activities/behaviors (resting, feeding, traveling, vocalizing, etc.), representative areas, seasons, times of day, weather and environmental conditions.

D. Long-term monitoring (at regular intervals)

I. =Environment= (physical, chemical)

II. =Whales= (distribution, abundance, movements, activity patterns, vocalization patterns, cow/calf ratios)

III. =Boat/Planes= (abundance, type, distribution, movements, activities)

IV. =Prey species=

V. =Fish catch=

APPENDIX D

[NOAA Letterhead--Cut off]

National Oceanic and Atmospheric Administration NATIONAL MARINE FISHERIES SERVICE

Was.h.i.+ngton, D.C. 20235

DEC 3 1979 F6:TRL

Mr. John Chapman Superintendent Glacier Bay National Monument National Park Service P.O. Box 1089 Juneau, Alaska 99802

Dear Mr. Chapman:

This letter responds to your August 4, 1979, request for consultation pursuant to Section 7 of the Endangered Species Act of 1973, as amended, relative to the population of the humpback whale in Glacier Bay, Alaska.

Your problem statement of the same date outlines the basic issue of human activity in Glacier Bay National Monument that might be affecting humpback whales. Section 7 of the Endangered Species Act requires that each federal agency insure that its actions do not jeopardize the continued existence of any listed species or result in the destruction or adverse modification of critical habitat of such species. The consultation process requires our comment and opinion on the problem.

Within this context, our response addresses those National Park Service (NPS) actions controlling human activity that may, in turn, affect the humpback whales within Glacier Bay.

=Biological Background=

In the North Pacific, the summer range of the humpback whale encompa.s.ses the area from Bering Strait south to the Subarctic Boundary (ca. 40 N lat) and extends in the east to about Point Conception, California, and the Sanriku Coast of Honshu Island in the west. Humpbacks range into shallow coastal waters more frequently than do most other balaenopterids and regularly occur in sheltered inside waters of Prince William Sound and the Alexander Archipelago of southeastern Alaska.

The wintering grounds of humpbacks in the North Pacific are centered in three areas: (1) the coast and adjacent islands of west-central Mexico; (2) the main Hawaiian Islands; and (3) the Bonin, Ryukyu, and Mariana Islands in the western North Pacific. Some humpbacks that summer in southeastern Alaska are known to migrate to both the Mexican and Hawaiian wintering grounds, although others are found in southeastern Alaska during all months of the year.

Prior to the rise of modern whaling in the late 1800's, the world population of humpback whales exceeded 100,000, mostly in the Southern Hemisphere. The North Pacific population probably numbered roughly 15,000 at the turn of the century.

Whaling in southeastern Alaska began in 1907 with the establishment of two land stations. The number of humpback whales at the start of this earliest exploitation is unknown. Consistent catch records are available only for 1912-1922, during which time 185 humpbacks were taken, with a peak catch of 39 in 1916.

Since 1922, no whaling has been conducted in the territorial waters of southeastern Alaska. However, the humpback whales of the inside waters were exposed to additional exploitation as they migrated across the high seas or through the coastal territorial waters of British Columbia, Was.h.i.+ngton, California, and Baja California.

By 1966, when humpbacks were accorded complete legal protection by the International Whaling Commission, the world population of the species had been reduced to about 5,000. The North Pacific population now numbers about 1,000, of which 600 or 700 winter in the Hawaiian Islands, and 200 or 300 winter in Mexico. Only a few humpbacks have been sighted on the western North Pacific wintering grounds in recent years. Since 1966 no trends in abundance have been observed either for the North Pacific population as a whole or on any of its wintering or summering grounds, including southeastern Alaska.

Based upon aerial and vessel surveys, the population that spends the summer in the inside waters of southeastern Alaska numbers at least 70. Photoidentification studies now underway tentatively reveal that the population may exceed 100. Although it ranges throughout the area from Sumner Strait northward, its main concentration areas are Frederick Sound-Stephens Pa.s.sage, where a minimum of 40 whales occurs, and Glacier Bay, where 20-25 whales occur. Humpback whales congregate in these areas to feed upon the summer blooms of euphausiids, herring, and capelin. Some whales arrive in June and stay on through early September, although as mentioned earlier, other animals appear to remain through the winter months.

When humpback whales historically began occupying Glacier Bay is unknown, but they have occurred there every summer over the past seven years of investigation. Photoidentification techniques indicate that certain individuals repeatedly return to feed there.

The availability of these and other feeding areas in southeastern Alaska has not been constant over the years. Although Glacier Bay has lately been a prominent feeding area, this was not always so since the area was covered by an ice sheet during the 18th century; at that time the humpback population was presumably at its maximum pre-exploitation level. There is some indication that a seasonal feeding area in Lynn Ca.n.a.l was avoided by humpbacks coincident with the onset of a herring fishery in 1972. With the cessation of that fishery, humpbacks reoccupied the area in 1979. The possibility cannot be discarded that these events are related.

=Present Glacier Bay Situation=

The NPS records indicate that during 1976 and 1977, 20-24 individual humpback whales moved into Glacier Bay during June and remained there into August. In 1978 this pattern of use changed when most of the animals departed by mid-July. In 1979 this use was modified further with fewer whales entering the Bay and very few of those remaining in the Bay. Observations prior to 1976 are more general in nature, rather than numerical counts of record.

Human use of the Bay is reflected in NPS records, to wit:

Visitor Large Private Fis.h.i.+ng Year Days s.h.i.+ps Boats Vessels ---- ------- ----- ------- ------- 1965 1,800 1969 16,000 115 1970 30,000 165 1975 72,000 113 353 824 1976 85,000 123 318 656 1977 120,000 142 534 523 1978 109,000 123 699 458

Most visitor use is via water access, with cruise s.h.i.+p and recreational craft visitation levels increasing rapidly in recent years.

The recent NPS study indicates that increasing vessel traffic in Glacier Bay may be implicated in the apparent departure of whales from Glacier Bay in 1978 and 1979. Data on the number of observed whale-vessel interactions in Glacier Bay enables calculation of the following "interaction" index (data for 1979 not available):

Whale-vessel Hours Index Year Interactions Observed (interactions/hour) ----- ------------ -------- ------------------- 1976 98 261.1 0.38 1977 201 407.1 0.49 1978 268 397.5 0.67

Thus the occurrence of whale-vessel interactions increased 29 percent and 76 percent respectively in 1977 and 1978 over the 1976 base level.

Despite mitigative regulations in 1979, observers noted that whale-vessel interactions continued at substantial frequencies.

The NPS data indicate that behavior of the humpback whales in Glacier Bay changed significantly in 1978. Comparison of the frequency distributions of behavioral responses indicates that, whereas distributions were the same in 1976 and 1977, both years were statistically different from 1978. In 1978, more avoidance behavior occurred than in previous years, suggesting that the whales reacted to the increased level of vessel traffic in 1978. However, the causal mechanism for these reactions (whether it be increased noise or visual stimuli) remains unknown.

All cla.s.ses of vessels were not implicated equally in the increased level of interactions which occurred in 1978. Cruise s.h.i.+p visitations actually decreased 14 percent in 1978 from the 1977 high, while charter/pleasure craft visitations increased 120 percent between 1976 and 1978. Commercial fis.h.i.+ng vessel traffic decreased 30 percent between 1976 and 1978. Charter/pleasure craft were often observed to change direction and travel toward whales for a closer look. Cruise s.h.i.+ps and commercial fis.h.i.+ng vessels, on the other hand, neither paused for nor actively followed whales. Thus the most likely source for increased interaction would appear to be the increased visitations by charter/pleasure craft in 1978.

This conclusion seems to agree with the perceptions of scientists examining other similar situations. The workshop on problems related to Hawaiian humpback whales, sponsored by the Marine Mammal Commission in 1977, concluded that vessel traffic not oriented toward whales did not ordinarily seem to disturb them. Indeed, it was concluded that whales seem readily to habituate to constant or familiar noises such as those produced by s.h.i.+ps of pa.s.sage. A recent review on the possible effects of noises emanating from offsh.o.r.e oil and gas development concluded that, unlike the abrupt response to sudden disturbances, most whales become habituated to low-level background noises such as would be a.s.sociated with s.h.i.+p traffic (Geraci, J. R., and D. J. St.

Aubin, "Possible Effects of Offsh.o.r.e Oil and Gas Development on Marine Mammals," prepared for the Marine Mammal Commission, August 1979.) Moreover, it was noted that such behavior forms the underlying basis for the success of whale watching cruises. Thus the erratic actions of charter/pleasure craft rather than the more constant action of cruise s.h.i.+ps may be the major factor in possible hara.s.sment by vessels within Glacier Bay.

Cruise s.h.i.+ps also may be implicated as potential sources of disturbance due to the physical setting within Glacier Bay. A direct a.n.a.logy may be seen in the lagoons of Baja California where gray whales calve. Heavy barge and freighter traffic a.s.sociated with the salt industry, as well as a dredge operating continuously in the lagoon's mouth, apparently drove gray whales out of Laguna Guerrero Negro between 1957 and 1967. The whales reinvaded in substantial numbers when vessel traffic was eliminated. The continued high use of Laguna Ojo de Liebre by gray whales suggests that the movement of salt barges, beginning there in 1967, may not have been such a nuisance.

However, since Laguna Ojo de Liebre is a much larger area than Laguna Guerrero Negro and has a much wider entrance, the whales there may simply have been able to move and coexist next to the barges. Such luxury of s.p.a.ce may not be available to the humpback whales of Glacier Bay and, due to geological configurations of its basin, vessel noise may be accentuated there. These factors may account for the unexpected reaction of humpbacks to cruise s.h.i.+ps in Glacier Bay.

The apparent departure of humpback whales from Glacier Bay in 1978 and 1979 may also be due in part to a change in the availability of food.

Euphausiids have historically been the primary feed within Glacier Bay in July-August, although little research has been done to compare yearly levels of this feed or to determine what level is necessary to support the whales. The only available information derives from vertical plankton tows by the REGINA MARIS in August 1979, which indicated that fewer euphausiids (5 percent) occurred in Glacier Bay as compared to Frederick Sound-Stephens Pa.s.sage. The humpbacks may have found the Glacier Bay food levels to be too low, particularly in the face of continued high vessel use, and simply departed to search for better concentrations elsewhere.

A similar abandonment of a prime feeding area, the Grand Banks, was observed for the Northwest Atlantic humpback population and was thought to be a.s.sociated with the overfis.h.i.+ng of capelin stocks there.

Consequently, the occurrence and distribution of humpback whales may be generally dependent upon the occurrence and availability of its desired prey species.

In a worst case a.n.a.lysis, Glacier Bay is a feeding ground, and its long-term abandonment would not be conducive to the conservation of the humpback whale. Up to 20 or 25 individual whales would relocate to other areas, increasing compet.i.tion for food there. In such case a greater expenditure of energy might be required to obtain the same quant.i.ties of food than would be required in Glacier Bay. An increased energy expenditure would tend to decrease the likelihood of humpbacks successfully increasing their numbers, since growth and the onset of s.e.xual maturity would be delayed.