TL: WALRUS IN BRISTOL BAY (GP) SO: Greenpeace International DT: June 11,1991 Keywords: oceans marine mammals pacific us greenpeace groups / INTRODUCTION The current time/area closures around Round Island, The Twins Island group and Cape Peirce became effective in 1990 for a period of two years. They are due to expire at the end of 1991, and the North Pacific Fishery Management Council is considering whether to continue or expand the buffer zones. Greenpeace International wishes to submit the following comments in support of Alternative 3 as listed in the Draft Environmental Assessment (Draft EA 1991), dated May 14, 1991; this is a seasonal groundfish fishing closure north of a line from Cape Constantine to the southernmost tangent of a 12-mile radius around Cape Peirce. The closure should be instituted for a period of five years, along with a scientific programme to monitor the walrus population in the area and evaluate the effect of the closure. Such an evaluation should be required to take place before the closure is changed in any way. Importance of the Area to Walrus The haul-outs in Bristol Bay are primarily used by mature males, thought to be from the Kuskokwim breeding area (Fay 1982). They arrive in early May in poor condition, and spend the spring and summer resting, moulting and feeding. Access to haul-out space is important to these walrus, in order to allow them to recover from the stress of the breeding period. The animals using this area are the mature bulls, which comprise a vital component of the total population, and their requirement for undisturbed habitat for rest and recovery must be recognized. The health of these males is important, and they should not be viewed as "surplus" or an expendable portion of the population. The limited data available show that the males spend periods of several days at sea, just south of Round Island and outside the proposed restricted area. Their behaviour at that time, alternating periods at the surface and diving, is consistant with foraging behaviour. Though hard evidence of extensive feeding in this area is scant, it is a reasonable assumption in view of the lack of evidence to the contrary. History and Effect of the Buffer Zone The pattern of walrus haul-out during the 1980's in northern Bristol Bay clearly shows a marked benefit to the walrus population (as indicated by the peak numbers counted ashore) every time human activity is restricted. As the walrus population recovered from low levels, caused by over- exploitation, Round Island and Big Twin Island were among the first sites in Bristol Bay to be re-occupied in the mid- 1950's. In the late 1970's to early 1980's, the maximum numbers hauled out on Round Island varied from 7,000 to 15,000, followed by a decline to about 6,000 in 1984. This decline has been attributed to disturbance caused by the developing herring fishery and increasing numbers of visitors (Draft EA 1991). When the controlled access area around Round Island was increased by the State of Alaska in 1984 from 0.5 to 2.0 miles, peak number hauled out increased to 12,378 by 1986. The following year, a large fleet of vessels began fishing for yellowfin sole in the vicinity of Round Island, and the peak walrus haul-out number plummetted to 5,300. The number further declined to 4,424 in 1988, the second year of the fishery. In 1989, when the controlled access zone was further extended to 3.0 miles, and when the yellowfin sole fleet operated elsewhere, the peak number of walrus hauled out climbed to 7,792. Numbers on Cape Peirce fluctuate markedly, and the area seems to provide an alternative haul-out site to Round Island. Evidence for this is the fact that walrus did not appear there until some two to three decades after they showed up on Round Island, and the seeming inverse synchrony in numbers at the two sites throughout the 1980's (e.g. coincident decline and increase from 1985 to 1986, and from 1988 to 1989). The fact that both sites are used by large numbers of walrus, however, implies that they are both required by the population under different conditions. These data indicate clearly a negative impact of disturbance resulting from fishing activity on the walrus population in Bristol Bay, and the positive results of restricting such activity. Walrus numbers remain well below the level recorded in the early-to- mid-1980's, emphasizing the need for even more protective measures. The proposal to extend the groundfish closure zone would be consistent with that need, and would provide a zone within which walrus could move, relatively undisturbed, between their various haul-out sites in northern Bristol Bay. The Acoustic Environment Walrus make a wide variety of sounds in both air and water, such as snorts, teeth-clacking and various whistles and bell-like sounds. Many of these are in the 50 Hz to 4 kHz range, and it is a reasonable assumption that walrus are sensitive to sounds within the same frequency range. Coincidentally, these frequencies are very similar to the underwater sounds generated by fishing vessels (Draft EA 1991). These sounds can be very loud, in the neighbourhood of 150-170 dB. It is thus quite probable that a highly gregarious and vocal species like the walrus would experience acoustic interference from large numbers of fishing vessels operating in the vicinity of their haul-outs. This interference is attested to by the observations of walrus behaviour recounted in the Draft EA (1991): walrus have been frightened off a haul-out beach by diesel motors passing by over one-quarter of a mile offshore, and a vessel passing by seven miles away completely masked walrus vocalisations. The long-term impact of a fishery near important walrus haul-outs is unknown. However, the dramatic decrease in the numbers of walrus hauling out on Round Island in 1987 and 1988, the two years of the yellowfin sole fishery in the area, suggests that it would be severe, and that the walrus would not readily return to the area as long as the disturbance continues. Fishing vessels operating just offshore from important walrus resting and haul- outs sites is not compatible with sound conservation measures. Tourism The Sanctuary is the only readily accessible place in the world where large numbers of walrus can regularly be seen. It is thus of global significance and deserves a high degree of protection from adverse impacts of any kind. This type of non-consumptive use of marine mammals is growing worldwide, and is of ever- increasing importance to the economies of areas fortunate enough to have large populations of marine mammals. A properly managed Sanctuary and local walrus habitat would be of considerable benefit to the Bristol Bay region and the State of Alaska as a whole. Feeding Interference The current issue of acoustic environment is only one example of the potential interaction between fishing activities and walrus. The Draft EA (1991) makes only passive reference to other possible impacts of bottom trawling. Bottom trawling is destructive of benthic communities (BEON 1990 and references therein), which would be particularly serious for a species such as walrus which feeds on benthic invertebrates, primarily bivalves. A large and healthy population of walrus can only be maintained in a healthy environment, and if the bottom community in Bristol Bay is damaged by trawling and other fishing activities, the consequences for walrus could be severe. The more general habitat requirements of walrus in Bristol Bay and the surrounding region need to be given serious consideration by the North Pacific Fishery Management Council in all of its decisions. Reasons for the Adoption of Alternative 3 Of the three alternatives listed in the Draft EA (1991), the third provides the greatest degree of protection for walrus, and Greenpeace International recommends that the Council adopt this alternative. However, the creation of a buffer zone as proposed in Alternative 3 is not sufficient. It must be accompanied by a biological monitoring programme designed to evaluate the impact of the zone on the walrus population. It is only in this way that it will be possible to tell if the measures adopted are effective, or need to be modified in some way. As Fay et al. (1989) point out, the walrus population has undergone wild fluctuations over the past 150 years precisely because insufficient monitoring programmes have been in place to detect problems with the population before they occur. Instead, once a crisis is detected, drastic measures are required to reverse the decline. A parallel situation is now occurring with Steller sea lions. It is a more sensible and mature approach to carefully monitor the walrus population, so as to prevent such crises from happening, and avoid unecessary problems for marine species and the fishing industry. Each time that activity in the region of the walrus haul-outs has been restricted, the number of animals has increased; it is thus not known if the optimum buffer zone has been created yet. Expanding it to that proposed in Alternative 3 allows an evaluation of the hypothesis that sufficient protection already exists. Until such time as no further increases in walrus numbers hauling out occur, it is not valid to assume that no further restrictions are necessary. It should be noted that Alternative 3 still allows other activities within the buffer zone which have detrimental impact on walrus, such as herring and salmon fishing. The decline in the numbers of walrus hauling out on Round Island which took place in the mid-to- late 1980's has been attributed, in part, to the developing herring fishery in the area. It is possible that the selection of Alternative 3 would result in some cost to the yellowfin fishery, such as increased operating costs and possible earlier closures due to bycatch quotas. However, these costs are countered by the greater catch per unit effort observed outside the proposed closed area. In addition, the shape of the closed area would render enforcement of the closure easier. At least in Togiak Bay, the fishery is catching sole in spawning condition. Caution is needed when fishing on spawning aggregations, and a relatively small "sanctuary" for spawning sole could benefit the population and help to ensure that its abundance remains high. There is a demonstrated need for protection for walrus in the area. The recognition by the Council, several years ago, of the importance of acoustical factors in the habitat of walrus was a wise and far-sighted act. In the face of an ever-increasing assault on the marine environment in the Bristol Bay area, the interests and profits of the fishing industry must not be allowed to eclipse whatever gains have been made in terms of habitat preservation. REFERENCES BEON 1990. Effects of beamtrawl fishery on the bottom fauna in the North Sea. Beleidsgericht Ecologisch Onderzoek Noordzee Report Number 8, Gravenhage, Netherlands. Draft EA 1991. Draft Environmental Assessment/Regulatory Impact Review, North Pacific Fishery Management Council, Anchorage, U.S.A. Fay, F.H. 1982. Ecology and Biology of the Pacific Walrus, Odobenus rosmarus divergens Illiger. North American Fauna, Number 74, United States Department of the Interior, Washington, U.S.A. Fay, F.H., B.P. Kelly and J.L. Sease. Managing the exploitation of Pacific walruses: a tragedy of delayed response and poor communication. Marine Mammal Science 5:1-16 This section is not to be included in the statement, for reasons I mentioned above. But I wrote it before speaking with Seagers, so am sending it out anyway for your information. The Status of Walrus Fay et al. (1989) examined the history of the management of Pacific walrus over the past 150 years, during which time the population has declined, due to over-exploitation, and subsequently recovered, upon three separate occassions. They considered that the recruitment rate in the late 1980's could have been as low as 1%, that it was far exceeded by the rate of removal, and that the population might already have been in decline. Monitoring methods in place at present (joint Soviet- American aerial surveys every five years plus counts at coastal haul-out sites) would preclude the detection of a decline with certainty "until long after it has taken place" (Fay et al. 1989, pg 10). The most recent population estimate available for Pacific walrus is 232,000 in 1985 (Gilbert 1989). However, this figure derives from two point estimates from aerial surveys, only one of which has a 95% confidence interval, and two estimates of numbers of walrus hauled out. Furthermore, the Soviet estimate from the aerial survey contains one very large clump. If that is considered to be an outlier, the total population estimate decreases to 171,067 (Gilbert 1989). Estimates for earlier years are 221,360 in 1975 and 246,140 in 1980. The results of the 1990 survey are not yet available, but it is thought that the population estimate will be "considerably lower than the 1985 survey" (Draft EA, pg 14). June 11, 1991