(Quarterly Report for April-May-June 1999)
Surveys of Beluga Whales in Cook Inlet
The most isolated of the five stocks of beluga whales found around Alaska is the small stock in Cook Inlet, separated from the others by the Alaska Peninsula. During spring and summer these whales are concentrated in a few river mouths along the northernmost portions of the inlet. Geographic and genetic isolation, in combination with a tendency towards site fidelity, makes this stock vulnerable to impacts from large or persistent harvests. As an expression of concern for declining numbers, Native hunters voluntarily stopped hunting for beluga whales in Cook Inlet in 1999, prior to a Congressional amendment to the Marine Mammal Protection Act which precluded beluga whale huning in Cook Inlet in the absence of a comanagment agrement between NMFS and Native hunters.
Management of the Cook Inlet stock of beluga whales has received considerable interest and concern. Accordingly, the National Marine Mammal Laboratory and the NMFS Alaska Regional Office conducted a 41.5-hour aerial survey of Cook Inlet from 8 to14 June 1999. This was a continuation of annual surveys flown each June/July since 1993 in cooperation with the Alaska Beluga Whale Commission and the Cook Inlet Marine Mammal Council. As in previous years, this years survey was flown in a twin-engine, high-wing aircraft at an altitude of 244 m (800 ft) and speed of 185 km/hr (100 kt) along a trackline 1.4 km from shore. The flights in 1999 included one or more searches along coastal areas around nearly the entire inlet and 1,790 km of transects across the inlet. Paired, independent observers searched on the coastal (left) side of the plane, where virtually all sightings occur, with a single observer and a computer operator/data recorder on the right side of the plane. In addition, each day a different visitor (representatives from various related organizations) observed from the left side. After finding beluga groups, a series of passes were made to allow at least two pairs of primary observers to make four or more counts of each group. Daily counts ranged from 75 to160 beluga whales near the Susitna River Delta (between the Beluga and Little Susitna Rivers), 13 to 43 in Knik Arm, and 17 to 30 in Chickaloon Bay. Belugas were not found in lower Cook Inlet. Sighting locations were consistent with locations where groups have been found over the past 7 years. The sum of the aerial estimates (using median counts from each site, not corrected for missed whales) ranged from 197 to 221 whales, depending on observer. The index count for 1999 is 217, which is slightly higher than the index counts for 1998 (193) but lower than all index counts by observers between 1993 and 1997 (264-324).
By Dave Rugh.
International Whaling Commission Scientific Committee Meeting
Scientists from the NMML participated in the annual Scientific Committee meeting of the International Whaling Commission (IWC) during 3-15 May 1999 in Grenada, West Indies. The meeting was organized by topic, via seven subcommittees/standing working groups:
The subcommittee on the Revised Management Procedure (RMP).
The standing working group on the development of the Aboriginal Whaling Management Procedures (AWMP).
The subcommittee on Aboriginal Subsistence Whaling (ASW).
The subcommittee on Comprehensive Assessment of Other Whale Stocks (CAWS).
The standing working group on Environmental Concerns (EC).
The standing subcommittee on Small Cetaceans (SM).
The subcommittee on Whalewatching (WW).
NMML scientists provided expertise to the RMP, AWMP and ASW, CAWS, EC and SM groups. The RMP subcommittee is concerned with the comprehensive assessment of large whales stocks that might be considered suitable for commercial whaling should the current moratorium be dropped. Of special relevance to NMML was the special working group within RMP that was tasked to develop operational stock definitions, based upon the types of data currently available to evaluate stock structure. The AWMP and ASW groups focused on development of protocols to set harvest limits for whale stocks hunted for aboriginal subsistence. Currently harvest limits are determined on a case-by-case basis for five whale stocks:
Bering-Chukchi-Beaufort stock of bowhead whales.
Eastern North Pacific stock of gray whales.
Western North Atlantic stocks of humpback whales.
North Atlantic stocks of minke whales.
North Atlantic stock of fin whales.
NMML scientists are involved in
development of strike limit algorithms as a means to set harvest limits in a manner
similar to that developed for commercial whaling. The CAWS subcommittee
considered topics ranging from a review of the Japanese scientific research whaling
program to the status of Southern Hemisphere blue and humpback whales, and Northern
Hemisphere right whales. Staff from the NMML provided background information
regarding ongoing efforts to determine the status of the remnant North Pacific right
whale population, including summer distribution and photographic and biopsy sampling.
The EC group focuses on the extent to which environmental issues (e.g., global climate change, contaminants, anthropogenic noise) might affect management concerns for large whales, should the moratorium on commercial whaling end or to the extent to which various environmental concerns might adversely affect the recovery of depleted stocks. This year, the group considered the relevance of two proposals: SOWER and Pollution 2000+. The SOWER proposal is directed at research to relate the distribution, abundance, and biomass of mysticete whales to the distribution and biomass of krill in a large area of the Southern Ocean and would be done in cooperation with ongoing international oceanographic programs, while the Pollution 2000+ proposal focuses on determining the effects of pollution and contaminants on large whales. In addition, the EC group supported development of an Arctic Research Initiative for next years meeting and considered issues related to the effects of anthropogenic noise on cetaceans, and a proposal for a workshop on habitat degradation. NMML scientists have taken a lead role in the EC group since its inception. The small cetaceans group focused on the efficacy of pingers to reduce cetacean bycatch, and on a worldwide assessment of beluga whales. NMML scientists highlighted the ongoing conservation efforts directed towards the Cook Inlet beluga stock and provided expertise on distribution and abundance of the four other stocks that occur off Alaska. Finally, the whale- watching subcommittee (WW) considered issues related to the development of scientific protocols for research on the effects of whale watching, including criteria for suitable areas for long-term studies. NMML scientists plan to become more active in this group, with special reference to whale watching in Alaska and Washington.
The following documents were authored or coauthored by NMML scientists and presented at the IWC meeting.
Breiwick, J. M. and D. P. DeMaster. 1999. Exploratory Type 3 fishery simulations. International Whaling Commission, Scientific Committee document SC/51/AWMP8, 9p.
Da Silva, Cibele Q., Judith Zeh, David Madigan, Jeff Laake, Dave Rugh, Lisa Baraff, William Koski, and Gary Miller. 1999. Capture-recapture estimation of bowhead whale population size using photo-identification data. International Whaling Commission, Scientific Committee document SC/51/AS23, 35p.
Gearin, Patrick J., Merrill E. Gosho, Jeff Laake, Larry Cooke, Robert L. DeLong, and Kirt M. Hughes. 1999. Experimental testing of acoustic alarms (pingers) to reduce bycatch of harbor porpoise, Phocoena phocoena, in Washington state. International Whaling Commission, Scientific Committee document SC/51/SM13, 22p.
Gosho, M.E., P.J. Gearin, J. Calambokidis, K.M. Hughes, L. Cooke, and V.E. Cooke. 1999. Gray whales in the waters of northwestern Washington in 1996 and 1997. International Whaling Commission, Scientific Committee document SC/51/AS9,15p.
Hobbs, R.C. and D.J. Rugh. 1999. The abundance of gray whales in the 1997/98 southbound migration in the eastern North Pacific. International Whaling Commission, Scientific Committee document SC/51/AS10, 13p.
Hobbs, Roderick C. and Janice M. Waite. 1999. Estimates of beluga whale group sizes in Cook Inlet, Alaska from aerial video recordings. International Whaling Commission, Scientific Committee document SC/51/SM9, 26p.
Hobbs, Roderick C., David J. Rugh, and Douglas P. DeMaster. 1999. Abundance of beluga whales in Cook Inlet, Alaska, 1994-1998. International Whaling Commission, Scientific Committee document SC/51/SM8, 23p.
Hughes, Kirt M., Larry L. Lehman, Patrick J. Gearin, Jeffrey L. Laake, Robert L. DeLong, and Merrill E. Gosho. 1999. Acoustic alarms and Pacific herring (Clupea pallasi). International Whaling Commission, Scientific Committee document SC/51/SM14, 9p.
Lerczak, James A., Kim E.W. Shelden, and Roderick C. Hobbs. 1999. The surfacing behavior of beluga whales in Cook Inlet, Alaska: results from suction cup attached VHF transmitter studies. International Whaling Commission, Scientific Committee document SC/51/SM10, 32p.
Lowry, Lloyd F., Douglas P. DeMaster and Kathryn J. Frost. 1999. Alaska Beluga Whale Committee surveys of beluga whales in the eastern Bering Sea, Alaska, 1992-1995. Alaska Beluga Whale Committee, Fairbanks, AK. 22p. International Whaling Commission, Scientific Committee document SC/51/SM34.
Lowry, Lloyd F., Douglas P. DeMaster, Kathryn J. Frost, and Wayne Perryman. 1999. Alaska Beluga Whale Committee surveys of beluga whales in the eastern Chukchi Sea, 1996-1998. Alaska Beluga Whale Committee, Fairbanks, AK. 20p. International Whaling Commission, Scientific Committee document SC/51/SM33.
Moore, Sue E., Douglas P. DeMaster, and Cynthia T. Tynan. 1999. Effects of global climate change on the ecology of whales in the Arctic. International Whaling Commission, Scientific Committee document SC/51/E9, 12p.
Rugh, David J., Kim E.W. Shelden, and Alisa Schulman-Janiger. 1999. Timing of the southbound migration of gray whales in 1998/99. International Whaling Commission, Scientific Committee document SC/51/AS11, 11p.
Rugh, David J., Kim E.W. Shelden, and Barbara A. Mahoney. 1999. Distribution of beluga whales in Cook Inlet, Alaska, during June and July, 1993-1998. International Whaling Commission, Scientific Committee document SC/51/SM12, 28p.
Rugh, David J., Roderick C. Hobbs, Kim E.W. Shelden, Barbara A. Mahoney, and Laura K. Litzky. 1999. Aerial surveys of beluga whales in Cook Inlet, Alaska, June 1998. International Whaling Commission, Scientific Committee document SC/51/SM11, 11p.
Shelden, Kim E.W., Jeffrey L. Laake, Patrick J. Gearin, David J. Rugh, and Janice M. Waite. 1999. Gray whale aerial surveys off the Washington coast, Winter 1998/99. International Whaling Commission, Scientific Committee document SC/51/AS12, 9p.
By Sue Moore and Douglas DeMaster.
NPFMC Addresses Steller Sea Lion Issues
At the June meeting of the North Pacific Fishery Management Council (NPFMC) in Kodiak, Alaska, Reasonable and Prudent Alternatives for the management of Steller sea lions were discussed in detail. Staff from the Alaska Regional Office and from the AFSC provided information on the contents of the Emergency Action under consideration and input related to Steller sea lion/fisheries interactions. The Council considered a suite of actions which would modify the Gulf of Alaska (GOA) and Bering Sea - Aleutian Islands (BSAI) pollock fisheries in order to avoid jeopardizing the continued existence of the western population of Steller sea lions and adversely modifying its critical habitat. The recommendations to NMFS included establishment of additional pollock trawl- exclusion zones around major haulouts in the GOA, expansion of one pollock no-trawl zone in the eastern Bering Sea, limits on the percentage of pollock harvest that can come from critical habitat, and season dates intended to spread out harvests temporally.
By Rich Ferrero.
Small Cetacean Aerial Survey in Bristol Bay
Three stocks of harbor porpoise (Phocoena phocoena) occur in Alaskan waters, one each in Southeast Alaska, Gulf of Alaska, and the Bering Sea. Population estimates for these stocks were reported as 10,301, 8,497, and 10,946, respectively. These estimates were based on a 3-year survey of subarctic Alaskan waters conducted from 1991 to 1993 and a correction factor developed for harbor porpoise surveys in Oregon and Washington. Known fishery takes do not currently exceed the potential biological removal (PBR), but a reliable estimate of human-caused mortality is unavailable due to lack of fishery observer placements in a large part of the range. It has been recommended that abundance estimates based on data older than 8 years not be used to calculate a PBR. Thus, a second 3-year harbor porpoise survey began in 1997 to support a new abundance estimate by 1999. The study will also include an abundance estimate for Dalls porpoise (Phocoenoides dalli) and other cetaceans.
Researchers from NMMLs Cetacean Assessment and Ecology Program conducted the third year of line transect aerial surveys for harbor porpoise and Dalls porpoise from 5 June to 4 July 1999 in Bristol Bay, Alaska A few survey lines were also flown in the Gulf of Alaska on the south side of the Alaska Peninsula where survey work was not completed in 1998. Surveys were conducted from a NOAA Corps operated Twin Otter aircraft, flown at an altitude of 152 m (500 ft) and an airspeed of 185 km/hr (100 knots). Two overlapping sawtooth tracklines were designated along the coastline of Bristol Bay. Both sides of each sawtooth were approximately 37 km with a 46 km base. Larger bays were also included in the survey. Vertical lines 18.5 km apart covered the center of Bristol Bay. Two primary observers surveyed from a bubble window on the left and right sides of the plane. An independent observer was positioned in a belly window. This observer surveyed the trackline directly below the plane, to record animals missed on the trackline by the primary observers.
All survey lines were completed in Bristol Bay, plus a small sample of lines from the south side of the Alaska Peninsula. A total of 44.9 survey hours were flown, with sightings of 176 harbor porpoise, 11 Dalls porpoise, 16 Pacific white-sided dolphins, 3 killer whales, 11 gray whales,16 humpback whales, 8 minke whales, 6 unidentified dolphins/porpoises, 5 unidentified whales, 27 harbor seals, 13 Steller sea lions, 108 walrus, and 5 unidentified pinnipeds. These numbers do not include the independent belly-window observer sightings. Results from this survey and from the previous two years of surveys will be used to estimate annual abundance of harbor porpoise and Dalls porpoise, one of the key pieces of information needed to manage marine mammal-fishery interactions, as required under the Marine Mammal Protection Act.
By Janice Waite.
Steller Sea Lion Field Work
NMML scientists conducted research on the condition and diet of Steller sea lions in the southeastern Bering Sea and along the Aleutian Islands chain from 21 June to 6 July 1999. Annual behavioral studies were also conducted on Marmot Island in the Gulf of Alaska. The survey area in the Bering Sea and along the Aleutian Islands included rookeries on the Islands of Akutan, Ulak, Kiska, Adak, Seguam, and Sea Lion Rock. The principal objectives of the survey were to collect blood, morphometric, and weight data from pups for assessment of health and condition; scats for analysis of the diet of adult females; and tissue for determination of the genetic relatedness between rookery groups across their range. Pups were also tagged to determine the degree of transience between rookery and haul-out sites. These data will support ongoing studies collected annually at these and other trend site rookeries range wide.
By Beth Sinclair.