APPENDIX C
APPENDIX D
| National Oceanic and Atmospheric Administration NATIONAL MARINE FISHERIES SERVICE | |
| Washington, 20235 |
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 encompasses 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, Washington, 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 Passage, 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 Canal 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:
| Year | Visitor Days | Large Ships | Private Boats | Fishing 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 ship 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):
| Year | Whale-vessel Interactions | Hours Observed | Index (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 classes of vessels were not implicated equally in the increased level of interactions which occurred in 1978. Cruise ship visitations actually decreased 14 percent in 1978 from the 1977 high, while charter/pleasure craft visitations increased 120 percent between 1976 and 1978. Commercial fishing 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 ships and commercial fishing 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 ships of passage. A recent review on the possible effects of noises emanating from offshore 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 associated with ship traffic (Geraci, J. R., and D. J. St. Aubin, "Possible Effects of Offshore 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 ships may be the major factor in possible harassment by vessels within Glacier Bay.
Cruise ships also may be implicated as potential sources of disturbance due to the physical setting within Glacier Bay. A direct analogy may be seen in the lagoons of Baja California where gray whales calve. Heavy barge and freighter traffic associated 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 space 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 ships 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 Passage. 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 associated with the overfishing 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 analysis, 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 competition for food there. In such case a greater expenditure of energy might be required to obtain the same quantities 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 sexual maturity would be delayed.
Conclusions
Our present interpretation of the available data is that uncontrolled increase of vessel traffic, particularly of erratically traveling charter/pleasure craft, probably has altered the behavior of humpback whales in Glacier Bay and thus may be implicated in their departure from the Bay the past two years. Our conclusion, then, is that continued increase in the amount of vessel traffic, particularly charter/pleasure craft, in Glacier Bay is likely to jeopardize the continued existence of the humpback whale population frequenting Southeast Alaska. The alteration in the distribution of the whales in Southeast Alaska can be expected to appreciably reduce the likelihood of the recovery of the North Pacific humpback population, especially when viewed as an incremental aggravation of the problem of humpback/human interaction in general.
Recommendations
Until research reveals the need for more specific action, if any, we offer the following as reasonable and prudent alternatives that the NPS should institute in Glacier Bay to avoid jeopardizing the continued existence of the North Pacific population of humpback whales:
We recommend that total vessel use of the Bay be restricted to 1976 levels, at the very least, since that year preceeded the high point of visitor use in Glacier Bay during 1977. Commercial use of the Bay is predicated on a permit system that should offer good control and accountability of the tour industry. The routing of large vessels is relatively easy to regulate. Recreational craft present the greater challenge to management control. The continuing increase in the amount of recreational traffic in the Bay lends considerable urgency to establishing effective controls.
Collectively, regulations should address vessel routing and vessel maneuvering. The NPS has already regulated these activities to some extent. Specific routes should be published, but the system should be flexible enough to accommodate changes of areas of concentrated feeding activity.
We further recommend curtailment of vessel operator discretion in pursuing, or approaching, whales. General guidelines prohibiting the pursuit or willful or persistent disturbance of whales through vessel maneuvering probably would offer better enforceability and public compliance than would detailed regulations based on specified distances. Vessel operator behavior should receive a thorough public educational effort, possibly through an informative notice to each vessel.
Finally, we recommend that monitoring of the humpback population and of whale-vessel interactions be continued and that all current data be fully analyzed. New research should also be undertaken (1) to characterize the food and feeding behavior of humpback whales in Glacier Bay and other areas; (2) to ascertain the acoustic characteristics of vessels within the Bay and in other areas with the aim of identifying equipment and/or modes of operation which are inimical to the whales; and (3) to compare behavioral responses of the humpbacks to vessels in Glacier Bay with those observed in other areas of southeastern Alaska.
The conclusions and recommendations stated herein constitute our biological opinion, and we consider consultation on this matter to be at an end. Should significant new information or factors not considered in this opinion arise, however, either we or NPS are obligated to reinitiate consultation.
| Sincerely yours, |
|
Terry L. Leitzell Assistant Administrator for Fisheries |