NOAA Technical Memorandum NMFS-AFSC-103

U.S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

Alaska Fisheries Science Center

August 1999

by

D. J. Rugh, M. M. Muto, S. E. Moore, and D. P. DeMaster

Status Review of the

Eastern North Pacific Stock

of Gray Whales
NOAA Technical Memorandum NMFS

The National Marine Fisheries Service's Alaska Fisheries Science Center

uses the NOAA Technical Memorandum series to issue informal scientific and

technical publications when complete formal review and editorial processing

are not appropriate or feasible. Documents within this series reflect sound

professional work and may be referenced in the formal scientific and technical

literature.

The NMFS-AFSC Technical Memorandum series of the Alaska Fisheries

Science Center continues the NMFS-F/NWC series established in 1970 by the

Northwest Fisheries Center. The new NMFS-NWFSC series will be used by

the Northwest Fisheries Science Center.

This document should be cited as follows:

Rugh, D. J., M. M. Muto, S. E. Moore, and D. P. DeMaster. 1999. 

Status review of the eastern north Pacific stock of gray whales. U.S. 

Dep. Commer., NOAA Tech. Memo. NMFS-AFSC-103, 93 p.

Reference in this document to trade names does not imply endorsement by the

National Marine Fisheries Service, NOAA.
August 1999

NOAA Technical Memorandum NMFS-AFSC-103

by

D. J. Rugh, M. M. Muto, S. E. Moore, and D. P. DeMaster

Status Review of the

Eastern North Pacific Stock

of Gray Whales

Alaska Fisheries Science Center

National Marine Mammal Laboratory

7600 Sand Point Way N.E., BIN C-15700

Seattle, WA 98115-0070

U.S. DEPARTMENT OF COMMERCE

William M. Daley, Secretary

National Oceanic and Atmospheric Administration

D. James Baker, Under Secretary and Administrator

National Marine Fisheries Service

Penelope D. Dalton, Assistant Administrator for Fisheries
This document is available to the public through:

National Technical Information Service

U.S. Department of Commerce

5285 Port Royal Road

Springfield, VA 22161

www.ntis.gov
-iiiAbstract

The National Marine Fisheries Service (NMFS) conducted a review of the status of

the Eastern North Pacific stock of gray whales (Eschrichtius robustus). This review

culminated in a workshop held by the National Marine Mammal Laboratory (NMML) in

Seattle, Washington, on 16-17 March 1999. Based on the continued growth of this

population (rising at 2.5% annually; currently at an estimated 26,600 individuals) and the

lack of evidence of any imminent threats to the stock, workshop participants

recommended the continuation of this stock’s classification as non-threatened. They also

concluded that abundance monitoring should continue at some level, especially as this

stock approaches its carrying capacity, and that, ideally, research should continue on

human impacts to critical habitats. This stock’s annual migrations along the highly

populated coastline of the western United States and their concentration in limited winter

and summer areas may make them particularly vulnerable to impacts from commercial or

industrial development or local catastrophic events. The Western North Pacific gray

whale stock has not recovered and should continue to be listed as endangered. 

The workshop and status review conclude the 5-year assessment of the Eastern North

Pacific gray whale stock following its removal from the List of Endangered and

Threatened Wildlife and Plants on 16 June 1994. 
-iv-
-vCONTENTS

Abstract ......................................................... iii

Background ......................................................... 1

Workshop objectives .................................................. 2

Factors to be considered in determining the status of gray whales .............. 3

Outline of available information ......................................... 3

1) Abundance, distribution, population trend, and status .................... 3

1.1) Abundance ................................................... 3

1.11) 1993/94 abundance ......................................... 3

1.12) 1995/96 abundance ......................................... 3

1.13) 1997/98 abundance ......................................... 3

1.14) Counting methodology ...................................... 4

1.15) Night travel rates .......................................... 4

1.16) Database management ...................................... 4

1.2) Distribution ................................................... 5

1.21) Migration ................................................ 5

1.211) Relative to the census station ............................. 5

1.2111) Shore-based observations ............................ 5

1.2112) Aerial observations ................................. 5

1.212) Timing in 1998/99 ..................................... 5

1.2121) Oregon ........................................... 5

1.2122) Washington - aerial ................................. 5

1.2123) Washington - shore-based ............................ 6

1.2124) California to Alaska ................................ 6

1.213) Travel rates ........................................... 6

1.214) Relative to Arctic and subarctic conditions .................. 6

1.22) Summering areas .......................................... 7

1.221) Arctic and subarctic .................................... 7

1.222) Washington ........................................... 7

1.23) Wintering areas ........................................... 7

1.3) Population trend ............................................... 8

1.4) Population status .............................................. 8

1.41) Criteria for ESA listing status ................................ 8

2) Calf production and pregnancy rate ................................... 8

2.1) Southbound migration at Granite Canyon/Yankee Point

 and Point Loma, California ...................................... 8

2.2) Southbound migration at Point Vicente, California ................... 9

2.3) Northbound migration at Point Vicente, California ................... 9

2.4) Northbound migration at Piedras Blancas, California ................. 9

2.5) Photogrammetric studies ........................................ 9
-vi3) Habitat use ...................................................... 10

3.1) Climate trends ............................................... 10

3.2) Food resources ............................................... 10

4) Potential anthropogenic concerns ..................................... 10

4.1) Contaminants ................................................ 10

4.2) Oil spills .................................................... 11

4.3) Noise ....................................................... 11

4.4) Entanglement in fishing gear .................................... 11

4.5) Salt extraction in Mexico’s lagoons ............................... 12

4.6) Commercial developments in Bahía Magdalena ..................... 12

4.7) Whale watching .............................................. 12

4.71) Regulations in Baja California Sur, Mexico .................... 12

4.72) Whale disturbance in Ojo de Liebre and San Ignacio Lagoons ..... 12

4.73) Whale disturbance and regulations in Bahía Magdalena .......... 13

4.74) Whale watching off California ............................... 13

4.75) Regulation suggestions in California .......................... 13

4.8) Strandings ................................................... 14

4.9) Ship strikes .................................................. 14

5) Aboriginal harvest ................................................. 14

5.1) Russian ..................................................... 14

5.2) Alaskan ..................................................... 15

5.3) Makah ...................................................... 15

6) Review of potential research projects .................................. 15

6.1) Abundance and trends in abundance ............................. 15

6.11) Granite Canyon, California ................................. 15

6.12) Point Vicente, California ................................... 16

6.13) Yaquina Head, Oregon ..................................... 16

6.14) Other sites .............................................. 16

6.141) Cape Sarichef, Alaska .................................. 16

6.142) Narrow Cape, Kodiak Island, Alaska ...................... 16

6.15) Stock assessment ......................................... 16

6.16) Stock identification and discreteness ......................... 16

6.2) Population health and viability .................................. 16

6.21) Calf counts .............................................. 16

6.211) Granite Canyon, California ............................. 16

6.212) Piedras Blancas, California .............................. 17

6.213) Point Vicente, California ............................... 17

6.214) Baja California Sur .................................... 17

6.22) Condition index .......................................... 17

6.23) Biological sampling ........................................ 17

6.231) Harvest ............................................. 17

6.232) Natural mortality ..................................... 17
-vii6.3) Distribution and habitat use .................................... 17

6.31) Baja California Sur ........................................ 17

6.32) Washington State ......................................... 17

6.33) Migration and foraging .................................... 17

6.331) Satellite tagging ....................................... 17

6.332) Distribution information ................................ 17

6.333) Migratory timing ...................................... 18

6.34) Summer distribution ....................................... 18

6.4) Anthropogenic concerns ....................................... 18

6.41) Contaminant loads ........................................ 18

6.42) Oil spills and post-spill monitoring ........................... 18

6.43) Noise ................................................... 18

6.44) Fishery interactions ....................................... 18

6.45) Commercial development in critical habitats ................... 18

6.451) Salt extraction in Baja California Sur ..................... 18

6.452) Oil and gas exploration and extraction .................... 18

6.453) Coastal development ................................... 18

6.46) Whale watching .......................................... 18

6.461) Regulations .......................................... 18

6.462) Studies .............................................. 19

6.463) Photographs ......................................... 19

6.47) Strandings ............................................... 19

6.48) Ship strikes .............................................. 19

6.5) Research priorities ............................................ 19

Summary .......................................................... 19

Acknowledgments ................................................... 20

Literature .......................................................... 22

Appendices

A) List of participants ............................................. 37

B) Abstracts ..................................................... 41
-1-

1

The U.S. Fish and Wildlife Service (USFWS) has jurisdiction over polar bears, sea otters, manatees,

dugongs, and walrus.

Background

Under the Marine Mammal Protection Act (16 U.S.C. 1361 et seq.; the MMPA), the

National Marine Fisheries Service (NMFS) has jurisdiction over most marine mammal

species1, including whales. Under section 4(a) of the Endangered Species Act (16 U.S.C.

1531 et seq.; the ESA) and 50 CFR part 424 of NMFS’ listing regulations, NMFS makes

determinations as to whether a marine mammal species should be listed as endangered or

threatened, or whether it should be reclassified or removed from the List of Endangered

and Threatened Wildlife and Plants (the List). Accordingly, NMFS conducted

comprehensive evaluations of the status of the Eastern North Pacific gray whale stock,

Eschrichtius robustus, (sometimes referred to as the “California stock”) in 1984 (Breiwick

and Braham 1984). Based upon their review, NMFS concluded that this stock should be

listed as threatened instead of endangered (49 FR 44774, 9 November 1984); however, no

further action was taken at that time. Another review was completed and made available

to the general public on 27 June 1991 (56 FR 29471). The 1991 review showed the best

available abundance estimate, in 1987/88, was 21,296 (CV = 6.05%; 95% CI = 18,900 to

24,000) whales and the average annual rate of increase was 3.29% (SE = 0.44%)

(Buckland et al. 1993). Back-calculations, dynamic response, and Bayesian estimations

indicated that this stock was probably approaching current carrying capacity (Reilly 1992). 

Therefore, NMFS determined that the Eastern North Pacific stock no longer met the

standards for classification as an endangered “species.” Although individual and

cumulative impacts might have the potential to adversely affect these whales, it was

determined that this stock was neither in danger of extinction throughout all or a

significant portion of its range (i.e., not endangered), nor was it likely to again become

endangered within the foreseeable future (i.e., not threatened). Therefore, on 22

November 1991 (56 FR 58869), NMFS proposed that this stock be removed from the

List. Of note, changes to the listing of this stock had no bearing on the status of the

Western North Pacific gray whale stock (sometimes referred to as the “Korean stock”),

which has not recovered and is still considered endangered throughout its range (USFWS

1997). After an extensive public comment period (22 November 1991 to 6 March 1992),

NMFS published a final notice of determination that the Eastern North Pacific stock

should be removed from the List (58 FR 3121, 7 January 1993). The population

abundance and trends in the population’s growth rate were deemed sufficient to allow this

stock to be removed from the List without first being down-listed to threatened status. 

As a result of NMFS’ determination, the U.S. Fish and Wildlife Service (USFWS)

removed the Eastern North Pacific stock of gray whales from the List under the ESA on

16 June 1994 (59 FR 31094) with the amendment of 50 CFR 17.11(h). To correspond

with that ruling, NMFS also removed this stock from the List under its jurisdiction (50

CFR part 222) through an amendment of 50 CFR 222.23(a). 

As required under section 4(g) of the ESA, NMFS drafted the “5-year Plan for

Research and Monitoring of the Eastern North Pacific Population of Gray Whales”
-2-

(NMFS 1993) to monitor the status of the stock for a period of at least 5 years following

the delisting. This plan (NMFS 1993:25) states that a “Task Group will conduct a

comprehensive ‘status review’ of the gray whale . . . Included in that report will be a

recommendation on whether to 1) continue the monitoring program for an additional 

5-year period; 2) terminate the monitoring program; or 3) consider changing the status of

the gray whale under the ESA.” The draft plan, dated October 1993, was not finalized by

the NMFS Office of Protected Resources; however, it has provided the framework and

guidelines for research, monitoring, and management over the past 5 years. The plan was

prepared by 11 NMFS scientists (the Gray Whale Monitoring Task Group), including

Howard Braham (Chair), Jeffrey Breiwick, Robert Brownell, Jr., Marilyn Dahlheim,

Douglas DeMaster (Vice-Chair), Kenneth Hollingshead, Jeffrey Laake, Stephen Reilly,

John Stein, Steven Swartz, and Grant Thompson. 

On 16-17 March 1999, 3 months prior to the conclusion of the 5-year period following

the delisting of the Eastern North Pacific gray whale stock, a workshop was convened by

NMFS at the Alaska Fisheries Science Center’s National Marine Mammal Laboratory

(NMML) in Seattle. Most of the original Task Group participated in this workshop, and

other participants were invited as well, depending on their expertise and contributions that

could help in the review process (see the participant list, Appendix A). The workshop

provided an opportunity for interactions among researchers conducting studies pertinent

to the evaluation of the status of gray whales. Agenda and abstract materials were

circulated prior to and following the workshop to provide additional time for detailed

reviews. An expanded agenda, with summaries of critical information, is included in the

following report under “Outline of Available Information.” Most of this material is

explained further in the attached abstracts (Appendix B). Research documents from the

past 5 years that pertain to this subject are in the literature section, including the literature

cited in the Status Review. 

Information included in the Outline of Available Information is inclusive of all

pertinent studies and available data collected up to and including 16 June 1999, the 5-year

anniversary of the removal of the Eastern North Pacific stock of gray whales from the

List. 

This Status Review document will be forwarded to the NMFS Assistant Administrator

for Fisheries for approval and release to the public. The NMFS Office of Protected

Resources will publish a Federal Register notice to announce the availability of this

document and invite public comment. 

Workshop objectives

The central objective of the status review and workshop held 16-17 March 1999 was

to evaluate available information pertinent to the health of the Eastern North Pacific stock

of gray whales. Questions to be answered through this process were: 

1. Was it appropriate to delist this stock 5 years ago?

2. Should this stock continue to be considered non-endangered and non-threatened?

3. Should the monitoring process continue for another 5-year period?
-3-

Factors to be considered in determining the status of gray whales

The ESA specifies regulatory elements that were used to determine the status of the

Eastern North Pacific stock of gray whales both in the delisting process in 1993-94 (see

above) and in the review of scientific materials available during the 5 years that followed

delisting (i.e., this report). Listing, reclassifying, or removing a species from the List is

based on review of five factors, of which only one need apply for a “species” to be listed

as either endangered or threatened (ESA: 16 U.S.C. 1533(a)(1); NMFS: 50 CFR 424): 

1. Present or threatened destruction, modification, or curtailment of its habitat or

range.

2. Overutilization for commercial, recreational, scientific, or educational purposes.

3. Disease or predation.

4. Inadequacy of existing regulatory mechanisms.

5. Other natural or manmade factors affecting its continued existence.

The workshop participants used these five factors as a guide to determine whether or

not the current status of the Eastern North Pacific gray whale stock should be changed

from non-threatened. The following information is a collection of research pertinent to

this decision. The outline was adapted from the list of research needs in the 5-year

monitoring plan (NMFS 1993:52). 

Outline of Available Information

1) Abundance, distribution, population trend, and status

1.1) Abundance

1.11) 1993/94 abundance: Systematic counts of southbound migrating gray

whales were conducted 10 December 1993 to 18 February 1994 at Granite

Canyon, California (Laake et al. 1994), the census site used most years since

1975 by NMML. In total, 1,864 pods (3,411 whales) were recorded during

447 hours of good or better watch conditions at the primary observation site. 

The abundance estimate was 23,109 (CV = 5.42%; 95% CI = 20,800 to

25,700).

1.12) 1995/96 abundance: Systematic counts of gray whales were conducted

from 13 December 1995 to 23 February 1996 at Granite Canyon (Hobbs et al.

in press). As during previous surveys, census methods included doublecounting to assess observer performance as well as aerial surveys and highpowered binoculars to document that a negligible fraction of migrating whales

passed beyond the sighting range of the observers. There were 2,151 pods

(3,928 whales) counted during 472.7 hours of standard watch effort. Data

analysis procedures were modified to account for differential sightability by

pod size. Population size was estimated to be 22,263 whales (CV = 9.25%;

95% log-normal CI = 18,700 to 26,500).

1.13) 1997/98 abundance: Systematic counts of gray whales were conducted

from 13 December 1997 to 24 February 1998 at Granite Canyon and Point

Lobos, California (Hobbs and Rugh 1999). Counting methods, similar to

previous surveys, included double-counting to assess observer performance
-4-

2

Pers. comm. Dave Rugh, National Marine Mammal Lab, AFSC, NMFS, 7600 Sand Point Way NE,

Seattle, WA 98115-0070.

3

Pers. comm. Kim Shelden, National Marine Mammal Lab, AFSC, NMFS,7600 Sand Point Way NE,

Seattle, WA 98115-0070.

and high-powered binoculars to document that a negligible fraction of

migrating whales passed beyond the sighting range of the observers. In total,

2,318 pods (3,643 whales) were counted during 435.3 hours of standard watch

effort. Data analysis procedures were identical to those used for the 1995/96

census. The population was estimated to be 26,635 whales (CV = 10.06%;

95% log-normal CI = 21,878 to 32,427).

1.14) Counting methodology: Systematic counts of gray whales have been

conducted by NMML during 3 of the past 5 seasons (1993/94, 1995/96,

1997/98) (Hobbs and Rugh 1999). These surveys covered the duration of the

southbound migration past the Granite Canyon research station. In addition to

the standard primary watch, a second, independent watch was conducted once

or twice daily. Offshore distribution of sightings was documented by

comparing the paired counts on the standard watch; by searches through

paired, fix-mounted 25 X binoculars; and by aerial surveys. In January 1993

and January 1994, pod-size estimation experiments involved an airplane

circling pods of whales as several observers independently estimated pod sizes

(Withrow in press). Tests of the counting system, but not full-season counts,

were conducted in January 1995 and January 1997 (Rugh2). Analytical

methods are described in Breiwick and Hobbs (1996).

1.15) Night travel rates: In studies conducted by Perryman et al. (1999a) in

January 1994, 1995, and 1996, there was no significant diel variation in gray

whale swimming speed. Prior to 15 January each year (the median migration

date), diurnal and nocturnal rates (average number of whales/hour) were not

significantly different; after 15 January, the nocturnal rate was significantly

higher (28%, SE = 11.6%) than the diurnal rate.

1.16) Database management: Census data have been collected on gray whales

during their southbound migration since 1952 (Shelden3). Currently the “raw”

count data are not readily available to the scientific community or the general

public. Therefore, researchers at NMML are in the process of creating a

single, uniform, and easily accessible database. Before this can occur, the

following tasks must be completed: 1) convert all computerized databases

(Yankee Point/Granite Canyon/Point Lobos study sites used from 1967/68

to1997/98) into a common format, and place all data into one master database;

2) find and incorporate data from Point Loma (1952-78) into the master

database; and 3) store the master database on CD-ROM for distribution to the

public. It is anticipated that this product will be available by September 2000,

pending support from the NMFS Office of Protected Species.
-5-

1.2) Distribution 

1.21) Migration

1.211) Relative to the census station

1.2111) Shore-based observations: In January 1995 and 1996, using

fixed-mounted 25X binoculars, paired independent searches for gray

whales resulted in detection probabilities of 0.97 for pod sizes greater

than 1 and 0.87 for single whales (5% of sampled population) within

the critical sighting range of 1-3 nautical miles (nmi) (1.8-5.6 km) of

shore (Rugh et al. in press).

1.2112) Aerial observations: Shelden and Laake (in press) compared the

distribution of whales within 3 nmi (5.6 km) north and south of Granite

Canyon during six aerial surveys (conducted concurrently with

shore-based surveys in 1979, 1980, 1988, 1993, 1994, and 1996). 

They found that whale distributions within the typical viewing range of

shore-based observers (3 nmi from shore) differed by year, but the

shifts in the distribution were minor (< 0.3 nmi; < 0.5 km). Inshore

(< 2.25 nmi; < 4.17 km) and offshore (> 2.25 nmi) distribution of gray

whale pods did not differ significantly between survey years. A mean

of 4.76% (SE = 0.85%) of the whale pods were observed beyond 2.25

nmi, and only 1.28% (SE = 0.07%) were observed beyond 3 nmi.

1.212) Timing in 1998/99 

1.2121) Oregon: Alternate half-hour counts were made during the

morning hours from 5 December 1998 through mid-February 1999

from the Yaquina Head Lighthouse (49 m above sea level) near

Newport, Oregon (Mate and Poff 1999). The first whale was sighted

on 23 December, and the peak passage occurred on 7 January. By

comparison with previous data from the same site (1978-81), the

migration started 3 weeks later than normal, and the migration peaked

6 days later than the latest date reported previously. Whales did not

tend to come nearshore to the degree experienced in previous years. In

this study, 60% of the sightings were greater than 5 nmi (> 9 km)

offshore and 20% were less than 3 nmi (< 5.6 km). 

1.2122) Washington - aerial: Shelden et al. (1999a, 1999b) conducted

six (4 complete and 2 partial) surveys in November and December 1998

and January 1999. Four pods (6 whales) were observed on offshore

transect lines from 5.5 to 47 km offshore, and two pods (2 whales)

were observed on coastal tracklines from Cape Flattery to Carroll

Island, Washington. The authors compared their results to surveys

conducted off Granite Canyon, California, and suggested several

factors that may have influenced the likelihood of detecting gray whales

off the northern Washington coast: timing of the peak of the migration,

lulls in the migration, width of the migration corridor, and limitations in

the field of view from the aircraft. Of these four factors, corridor width
-6-

appeared to be the most likely contributor to reduced observer

detection rates.

1.2123) Washington - shore-based: Gray whales were seen on three

occasions (2, 4, and 13 December) during a survey conducted from the

tower of the Tatoosh Island lighthouse, on the northwesternmost tip of

Washington State, between 30 November and 16 December 1998

(Jones 1999). The maximum possible sighting distance was estimated

at 25 km, but gray whales were only seen at a range of 0.6-5.9 km from

shore. It is possible that whales passed offshore, out of the observer’s

sighting range, or that this time period represented the very early stages

of the southbound gray whale migration past Washington. 

1.2124) California to Alaska: According to Rugh et al. (1999a, 1999b),

the median sighting date of southbound gray whales prior to 1980 was

8 January (ranging from 5 to14 January) at the Granite Canyon

research station. However, since 1980 there has been a 1-week delay

in the peak of the migration such that the median date is now closer to

15 January (ranging from 12 to 19 January). Using a travel rate of 144

km/day (Swartz et al. 1987) between shore stations, the expected peak

dates in 1998/99 should have been 5 January for Tatoosh Island; 8

January for Yaquina Head; 15 January for Granite Canyon; and 18

January at Point Vicente, near Los Angeles, California. Although no

observations were made at Granite Canyon in 1998/99, sightings

collected at Yaquina Head (Mate and Poff 1999) and Point Vicente

(Schulman-Janiger 1999a) indicate that the southbound migration was

within 1 or 2 days of the expected date.

1.213) Travel rates: Gray whales migrate at a rate of approximately 144

km/day (SD = 31 km/day), based on radio tags placed on whales near the

Granite Canyon research station (Swartz et al. 1987). This travel speed

was similar to rates calculated from a comparison of timings of peaks in

sightings as whales migrated south past several shore stations ( ̄x = 139

km/day; SD = 18 km/day) (Rugh et al. 1999a, 1999b). 

1.214) Relative to Arctic and subarctic conditions: Rugh et al. (1999a,

1999b) determined that gray whale migratory timing is remarkably regular: 

the 20 peaks observed at Granite Canyon during the southbound migration

from 1967/68 to 1997/98 varied less than 4 days from the overall median

dates. Regularity of this sort is likely driven by photoperiod (that is,

shortening day lengths), not by weather. Arctic and subarctic temperatures

and ice conditions are far from being so regular. Inter-year variations of a

few days in migratory dates may be explained in part by variations in the

median location of whales in the Bering or Chukchi Seas just prior to the

onset of the migration. The farther north the whales are in autumn, the

shorter the photoperiod will be, which might accelerate the onset of their

southbound migration. 
-7-

1.22) Summering areas

1.221) Arctic and subarctic: During aerial surveys in the Alaskan Chukchi

and Beaufort Seas in 1982-91 (Moore and DeMaster 1997), gray whales

were associated with virtually the same habitat throughout the summer

(40 m depth and < 1% ice cover) and the autumn (38 m depth and < 7%

ice cover), unlike bowhead and beluga whales. Moore and DeMaster

(1997) believe that shallow coastal and offshore-shoal areas provide habitat

rich in gray whale prey, and there is little reason for whales to abandon this

habitat prior to winter onset. The association of gray whales with discrete

offshore shoals in the northern Chukchi Sea may indicate that these are

important feeding areas for the expanding population.

1.222) Washington: From 1984 to 1997, 168 individual gray whales were

photo-identified (as seasonal resident whales from spring through fall) in

coastal areas of Washington State (Calambokidis and Quan 1999, Gosho

et al. 1999a, 1999b). Gray whales showed some localized site fidelity but

also moved widely within and between years. Expanded research in 1998

(Calambokidis and Quan 1999) revealed that seasonal resident gray whales

in Washington also used coastal areas from northern California to southeast

Alaska from spring to fall. This large feeding range may account for

inconsistent year-to-year resightings. Whales in northern Puget Sound

showed strong site fidelity for part of the season and then moved to

unknown areas. Use of southern Puget Sound was variable, mortality was

high, and whales were rarely seen more than once.

1.23) Wintering areas: According to Urbán et al. (1997, 1998a, 1998b), the

annual maximum count of all whales in San Ignacio Lagoon during the winters

of 1978-85 averaged 348.7 (SE = 35.2) adults, of which 238.2 (SE = 36.7)

were single whales and 110.5 (SE = 27.6) were cow-calf pairs. From 1996 to

1998, there was an average of 230 (SE = 18.4) adults in the lagoon, of which

140 (SE = 33.5) were single whales and 90 (SE = 37) were cow-calf pairs. 

During photo-identification studies in the lagoon in 1996-98, 752 whales were

identified, including 411 single whales, 332 cow-calf pairs, and 9 whales which

could not be classified. Of these, 120 whales were resighted: 14 single whales

and 106 cow-calf pairs. Cow-calf pairs stayed in the lagoon an average of 19.1

days (± 4.8 95% CI) in 1996, 19.6 days (± 3.5 95% CI) in 1997, and 20.6 days

(± 4.1 95% CI) in 1998, while single whales used the lagoons an average of 2.6

days (± 0.9 95% CI) in 1996, 6.2 days (± 3.2 95% CI) in 1997, and 5.6 days

(± 2 95% CI) in 1998. During surveys in 1996 and 1998 (Urbán et al. 1998b),

most whales were observed heading west off the coast of Bahía Ballenas, Baja

California Sur, Mexico. Single whales were observed farther offshore than the

cow-calf pairs. The number of single whales recorded in 1996 and 1998 was

higher than the recorded number of cow-calf pairs. Similar traveling patterns

and group composition were reported by Sánchez Pacheco and Valdés Aragón

(1997) in 1997. 
-8-

1.3) Population trend: Between 1967/68 and 1995/96, the Eastern North Pacific

gray whale population increased 2.5% per annum (SE = 0.3%), and the estimated

asymptote from a logistic model was 26,046 (SE = 6,281) with the inflection point

in 1971 (SE = 6.5) (Buckland and Breiwick in press). Using a generalized linear

model to fit abundance estimates from 1967/68 to 1997/98, the ROI (rate of

increase) was 2.52% per annum (SE = 0.27%); using a logistic model, K (carrying

capacity) was estimated to equal 37,364 (SE = 24,854), which is larger by 11,000

than a similar estimate based on the 1967/68 to1995/96 data; and RY (replacement

yield) equaled 612 (Breiwick 1999). Density-dependent slowing of the population

growth rate was supported by use of a Bayesian statistical method to compare the

fit of the data to density-dependent versus density-independent models. Point

estimates of the equilibrium population size ranged from 24,000 to 32,000,

depending on the model (Wade and DeMaster 1996). Using a Bayesian statistical

method to assess the stock with 1966/67 to1995/96 data, point estimates of

carrying capacity ranged from 24,640 to 31,840; the median depletion (population

size as a fraction of carrying capacity) was 0.75, with a lower 2.5th percentile of

0.36; the probability that the population is still below one-half of the carrying

capacity was 0.21, and the probability that it is still below its maximum sustainable

yield level was 0.28 (Wade in press).

1.4) Population status

1.41) Criteria for ESA listing status: Using 19 years of abundance estimates for

the Eastern North Pacific gray whale, Gerber et al. (in press) sampled subsets

of the original survey data to identify the minimum number of years of data

required to consistently recommend removing the population from the ESA

List of Endangered and Threatened Wildlife. These subsets of data were then

analyzed using their proposed classification criteria. It was found that a

quantitative decision to delist was unambiguously supported by 11 or more

years of data, but precariously uncertain with fewer than 10 years of data.

2) Calf production and pregnancy rate

2.1) Southbound migration at Granite Canyon/Yankee Point and Point Loma:

Calf sightings (number of calves/total whales) recorded by NMFS observers during

the gray whale southbound migrations were summarized by Shelden et al. (in

press) for 1952-95 and by Shelden and Rugh (1999) for 1995-98. Percentages of

calves ranged from 0.0 to 0.2% from 1952-74, 0.1-0.9% from 1984-95, and

0.3-1.5% from 1995-98. The apparent increase in the percentage of calf sightings

may be related to a trend towards successively later migrations over the 43-year

observation period, or it may be due to an increase in spatial and temporal

distribution of calving as the population has increased. The distribution of cows

with calves relative to shore was similar to earlier years where the majority of

sightings occurred inshore of the main migration corridor (1.4-2.8 km) during both

shore-based and aerial surveys. Aerial surveys (between 1979 and 1994) indicated

that shore-based observers missed 62% of the calves within their viewing area 
-9-

4

Pers. comm. Wayne Perryman, Southwest Fisheries Science Center, NMFS, P.O. Box 271, La Jolla, CA

92038-0271.

(0-2.6 km from shore), suggesting that calves are under-represented in the data

(Shelden et al. in press). 

2.2) Southbound migration at Point Vicente: Schulman-Janiger (1999b), of the

American Cetacean Society, Los Angeles Chapter (ACS/LA), reported that

percentages of calves in the southbound migrations from 1983/84 to 1989/90

ranged from 0.5% to 2.5%, averaging 1.7%. From 1990/91 to 1992/93, these

percentages increased to 3.0-3.9%, averaging 3.5%. The calf percentages from

1993/94 to 1998/99 ranged from 2.0% to 8.6%, averaging 4.6%. However, the

calf count in the 1998/99 migration (n = 15; 2.2%) was one of the lowest in the

past nine seasons. The highest calf count (n = 106; 8.6%) was in the 1997/98

season. 

2.3) Northbound migration at Point Vicente: Schulman-Janiger (1999b) reported

that percentages of newborn calves sighted in the ACS/LA surveys of the

northbound migrations from 1983/84 to 1991/92 ranged from 0.9% to 8.3%,

averaging 3.4%. From 1992/93 to 1997/98, these percentages generally increased,

ranging from 4.3% to 13.8% and averaging 9.6%. Some of the highest

percentages, ranging from 9.4% to 13.8% (averaging 11.2%), occurred in recent

years (1995/96 to1997/98). These were substantially higher than previously

published figures for California waters. The highest calf count (n = 222, 13.8%)

occurred in the 1996/97 season and was more than double the count of any of the

preceding nine seasons. However, the percentage of calves in the 1998/99

northbound migration was only 2.5% (n = 34), well below percentages seen in

recent years.

2.4) Northbound migration at Piedras Blancas: Perryman et al. (1999b) conducted

shore-based surveys at Piedras Blancas in central California to estimate the number

of calves in the northbound migration. There were 1,000 calves (SE = 88.85) in

1994; 601 calves (SE = 69.56) in 1995; 1,141 calves (SE = 72.23) in 1996; 1,439

calves (SE = 78.62) in 1997; a preliminary estimate of 1,316 calves (SE = 77.56)

in 1998; and a preliminary estimate (Perryman4) of 471 calves (SE = 77) in 1999. 

Calf production indices (calf estimate/total population estimate) were 4.5%, 2.6%,

5.1%, 6.5%, 5.9%, and 1.8% for the years 1994-99, respectively . 

2.5) Photogrammetric studies: According to Perryman and Lynn (1999), the

southbound migration is led by large whales, many of them pregnant females;

juvenile whales usually arrive late in the migration. Based on the proportion of

pregnant and recent postpartum females, 15 January was estimated to be the

median birth date for the Eastern North Pacific stock of gray whales. The

estimated length at 1 year was 8.6 m. Results indicated that relatively small

changes in condition or fatness of gray whales are detectable in measurements

from photographs.
-10-

3) Habitat use

3.1) Climate trends: Changes in the extent and concentration of sea ice in the Arctic

Ocean over the past 20-30 years, coincident with warming trends, may alter the

seasonal distributions, geographic ranges, patterns of migration, nutritional status,

reproductive success, and ultimately the abundance and stock structure of some

species (Tynan and DeMaster 1997a). Effects of climate warming on Eastern

North Pacific gray whales are unknown, but studies of benthic-pelagic coupling in

the Arctic and subarctic (e.g., Grebmeier and Barry 1991) suggest depression of

production in surface waters that may lead to reduced availability of gray whale

prey in primary feeding areas offshore of Alaska.

3.2) Food resources: According to Highsmith and Coyle (1992), gray whales rely on

rich benthic amphipod populations in the Bering and Chukchi Seas to renew fat

resources needed to sustain them during their winter migration to and from Baja

California Sur. Gray whale feeding areas offshore of northern Alaska are

characterized by low species diversity, high biomass, and the highest secondary

production rates reported for any extensive benthic community. Stoker (in press)

studied one of the high-use areas, the central Chirikov Basin between St. Lawrence

Island and the Bering Strait, and found that gray whales disturb at least 6% of the

benthos each summer and consume more than 10% of the yearly amphipod

production. There are indications that this resource is being stressed and that the

gray whale population may be expanding its summer range in search of alternative

feeding grounds. Specifically, Highsmith and Coyle (1992) showed that the

abundance and biomass of the amphipod community decreased during the 3-year

period from 1986 to 1988, resulting in a 30% decline in production. They noted

that high-latitude amphipod populations are characterized by low fecundity and

long generation times, and that large, long-lived individuals are responsible for the

majority of amphipod secondary production. Therefore, a substantial reduction in

the density of large individuals in the population will result in a significant, longterm decrease in production.

4) Potential anthropogenic concerns

4.1) Contaminants: Tilbury et al. (1999) studied contaminants in gray whales. 

During migrations, prolonged fasting may alter the disposition of toxic chemicals

within the whales’ bodies. Gray whales feeding in coastal waters may be at risk

from exposure to toxic chemicals in some regions. The higher concentrations of

polychlorinated biphenyls (PCBs) found in stranded animals compared to

harvested animals may be due to the retention of organochlorines in blubber during

fasting rather than to increased exposure to these contaminants. The elevated

concentrations of certain trace elements (e.g., cadmium) found in some tissues,

such as kidneys, of stranded animals and the high levels of aluminum found in the

stomach contents and tissues of harvested whales, compared to other marine

mammal species, is consistent with the ingestion of sediment by gray whales.
-11-

5

Pers. comm. Ed Lochbaum, Marine Mammal Coordinator, Department of Fisheries and Oceans, 

3225 Stephenson Point Road, Nanaimo, B.C., V9T 1K3 Canada.

4.2) Oil spills: Moore and Clarke (in press) reported that gray whales were seen

swimming through surface oil from the Exxon Valdez oil spill along the Alaskan

coast. Also, gray whales showed only partial avoidance to natural oil seeps off the

California coast. Laboratory tests suggest that gray whale baleen, and possibly

skin, may be resistant to damage by oil, but spilled oil or oil dispersant in a primary

feeding area could negatively affect gray whales by contaminating benthic prey.

4.3) Noise: Moore and Clarke (in press) summarized studies of short-term behavioral

responses to underwater noise associated with aircraft, ships, and seismic

explorations. These studies indicate a 0.5 probability that whales will respond to

continuous broadband noise when sound levels exceed ca. 120dB, and to

intermittent noise when levels exceed ca. 170dB, usually by changing their

swimming course to avoid the source. They also reported that preliminary results

from studies to determine gray whale responses to a low-frequency active (LFA)

anthropogenic source indicate that whales avoided exposure to transmissions in the

100-500 Hz frequency band at levels of 170-178 dB by deviating from their

swimming path. Moore and Clarke (in press) noted that gray whales ‘startled’ at

the sudden onset of noise during playback studies but demonstrated a flexibility in

swimming and calling behavior that may allow them to circumvent increased noise

levels. Conversely, some whales swim toward small skiffs deployed from whale

watching boats in breeding lagoons, seemingly attracted by the noise of idling

outboard engines. Gray whales sometimes change course and alter their swimming

speed and respiratory patterns when followed by whale watching boats. Dahlheim

(1984, 1988) found that gray whales respond to variation in underwater noise by

changing the structure and timing of their calls. Ambient noise (both natural and

man-made) has a profound affect on the behavior of this coastal species, causing

them to modify their calls to optimize signal transmission and reception. Jones et

al. (in press) described the significant decline in the number of whales using San

Ignacio Lagoon during acoustic playback research conducted in the winter of

1984, and the re-occupation of this lagoon the following winter, although the

numbers seen in 1985 were lower than observed during the 1978-82 period. The

noise playback experiments documented alterations in vocal behavior and a

significant decline in the number of whales occupying the lagoon during

continuous playback (24-hour periods) of industrial noise (Dahlheim 1988). This

experiment demonstrated the sensitivity of gray whales to noise disturbance within

the lagoon. 

4.4) Entanglement in fishing gear: From 1990 through 1998, 47 gray whales were

reported entangled in fishing gear off the coasts of Alaska, Washington, Oregon,

and California. Of these animals, 13 appeared to have survived; the remaining 34

were either mortalities or their status was unknown (Hill 1999a). A whale

mortality, due to entanglement in a net pen, was reported in British Columbia in

1999 (Lochbaum5). 
-12-

6

Pers. comm. Lorenzo Rojas Bracho, Bahía Vizcaíno 476, Col. Moderna, Ensenada, B.C., 22860 México.

7

Pers. comm. Jorge Urbán Ramírez, Programa de Investigacion de Mamiferos Marinos, Dept. de Biologia

Marina, Universidad Autonoma de Baja California Sur, Ap. Post. 12-B, La Paz, B.C.S., 23081 México.

4.5) Salt extraction in Mexico’s lagoons: Exportadora de Sal, sometimes referred to

as ESSA, has operated a salt extraction facility at the town of Guerrero Negro,

midway along the Pacific Coast of Baja California Sur, since 1954, and it is

planning to expand its operation to San Ignacio Lagoon (Mate 1995). In 1994,

ESSA entered into negotiations with the Mexican environmental authorities to

expand its salt extraction and marketing activities within the buffer zone of the

El Vizcaíno Biosphere Reserve. Specifically, they propose development of a

52,150 ha salt production facility on the shore of San Ignacio Lagoon (Dedina and

Young 1995a). In 1995, due to insufficiencies in the Statement of Environmental

Impact (MIA, acronym in Spanish), the Mexican authorities denied the permit for

the San Ignacio Lagoon expansion and established a Scientific Committee, made

up of seven specialists of different nationalities, to specify the terms of reference

necessary for a new MIA. This task was completed in July 1996; however, to

date, no proposal based on the new terms of reference has been received

(SEMARNAP 1997).

4.6) Commercial developments in Bahía Magdalena: The growth of gray whale

tourism in the North Zone of Bahía Magdalena has led to a proposed Japanese

owned and financed tourist resort development at Bahía Magdalena (Dedina and

Young 1995a). Although this represents a potential threat to the whales and their

habitat, at this time, there are no plans to proceed with this development (Rojas

Bracho6).

4.7) Whale watching

4.71) Regulations in Baja California Sur, Mexico: Urbán Ramírez7 reported

that whale watching is allowed in every lagoon in Baja California Sur except in

the southern part of Bahía Magdalena (also see Sánchez Pacheco 1997a). 

Since 1997, government whale watching regulations (modified annually) have

existed for commercial operators. There are currently four specific whale

watching areas in the lagoons where the numbers of boats and methods of

approach are regulated. There are no minimum approach distances, but whales

cannot be chased. 

4.72) Whale disturbance in Ojo de Liebre and San Ignacio Lagoons: A

change in a whale’s direction of movement is considered an indicator of

disturbance. Sánchez Pacheco (1997b) defined a procedure to estimate the

Maximum Simultaneous Number (NMS, acronym in Spanish) of vessels that

can watch whales in an area without disturbing more than 50% of them. The

procedure was applied in Ojo de Liebre Lagoon and San Ignacio Lagoon

during 1995. Vessels followed selected whales, while observers recorded

whale reactions and the distance between the vessel and disturbed whales. 
-13-

8Héctor Pérez-Cortés Moreno, Instituto Nacional de la Pesca, CRIP, Km 1, Carretera a Pichilingue, 

La Paz, B.C.S., 23020 México.

9Alisa Schulman-Janiger, American Cetacean Society, 2716 S. Denison, San Pedro, CA 90731

The NMS was 6 vessels in each of two areas in Ojo de Liebre Lagoon and 13

vessels in San Ignacio Lagoon.

4.73) Whale disturbance and regulations in Bahía Magdalena: A shore-based

study was conducted in the northern part of Bahía Magdalena, Estero A.

Lopez Mateo, to observe the effect of whale watching boats on whale behavior

(Pérez-Cortés Moreno8). In this narrow and shallow area of the lagoon,

single-day visits predominate and enforcement is difficult. Regulations permit

a maximum of 22 boats in the area at one time; boats must have a permit and

fly a flag when whale watching; and only two boats can be close to a whale at

one time. Preliminary results indicated that whales did not interact with the

boats in 65.3% of the sightings; no impacts were recorded in 28.4% of the

sightings; and behavior changes were recorded in only 6.3% of the sightings. 

Not all of these changes were negative as there were some “friendly” whales

that approached boats. Although there did not appear to be any negative

impacts on the whales, increased enforcement was recommended since there

was an “observer effect” on the boat operators (i.e., they were more likely to

obey regulations if under observation).

4.74) Whale watching off California: Schulman-Janiger9 described whale

watching guidelines and activities off the coast of California. The guidelines

specify a minimum approach of 100 yards (100 m) and recommend that vessels

approach whales from the rear and avoid separating cow-calf pairs. However,

there is very little enforcement, and it is hard to prove harassment. Whale

watching is a major seasonal industry off California. For example, a total of 

44,125 people in 1996 and 41,879 people in 1997 participated in the Cabrillo

Whalewatch Program trip cruises alone (on 6 vessels) off Los Angeles,

California . During the mid-1980s, abundant nearshore gray whale sightings

prompted many operators to start to guarantee whale sightings, which led to

increased pressure to locate whales. During 1989-91, the number of nearshore

gray whale sightings decreased, and commercial vessels began to cooperate to

locate whales. Several vessel operators combined assets to charter a spotting

plane, and another vessel hired staff to spot whales from the ACS/LA survey

site. A significant problem is the number of private boats that follow

commercial boats. Off Los Angeles, there can be 8-12 boats following one

whale. Jet-skis are also a significant problem; they harass whales and can

separate cows from calves close to shore.

4.75) Regulation suggestions in California: Recommendations for improved

regulations (Schulman-Janiger9) include: 1) issue permit numbers to whale

watching vessels and require them to fly flags while following a whale; 2) make

ship traffic aware of whales in the area; 3) set speed limits for vessels moving

in and out of harbors; 4) do not extend the current whale-watching season
-14-

10Pers. comm. Mary Sternfeld, NMFS, AK Region, Protected Resources, P.O. Box 21668, Juneau, 

AK 99802.

11Pers. comm. Brent Norberg, NMFS, WASC, 7600 Sand Point Way NE, Seattle, WA 98115-0070.

12Pers. comm. Joe Cordaro, NMFS, WASC, 501 West Ocean Blvd, 4200 Long Beach, CA 90802-4213.

13Pers. comm., Robert Brownell, Jr., Southwest Fisheries Science Center, NMFS, P.O. Box 271, La Jolla,

CA 92038-0271.

(26 December-31 March) to target cow-calf pairs; 5) do not guarantee

sightings; and 6) schedule boat races to avoid concentrations of whales,

especially cow-calf pairs, in the area.

4.8) Strandings: From 1990 to 1998, there were 250 gray whale strandings

(excluding the stranded whales in which the cause of death was due to

entanglement) reported along the coasts of Alaska, Washington, Oregon, and

California (Hill 1999b). In 1999 (as of 16 June), there were 24 gray whale

strandings reported in Alaska (Sternfeld10); 6 in British Columbia--not including

one death due to entanglement (Lochbaum5); 21 in Washington (11 on the coast;

10 within inland waters) (Norberg11); 1 in Oregon (Norberg11); and 32 on the

California coast (Cordaro12). Pérez-Cortés Moreno (1999) reported that from

1975 to 16 June 1999, there were 518 strandings in Mexico (also see Sánchez

Pacheco 1998). Thorough surveys were conducted in Mexico in the early 1980s

and in 1998 and 1999, while relatively high numbers of strandings were recorded

only in 1980 (53 whales), 1982 (46), 1991 (45), and 1999 (114). Although the

number recorded in 1999 was high relative to other years, this was in part due to

increased survey effort. These strandings occurred in many locations between

December 1998 and June 1999 and were not related to a single stranding event. 

Of 89 stranded whales examined, 72% were adults, and of these, 78% were

females. 

4.9) Ship strikes: From 1990 to 1998, seven vessel strikes of gray whales were

reported off the coasts of Alaska, Washington, Oregon, and California (Hill

1999c). Three of these animals appeared to have survived, while the other four

were either mortalities or their status was unknown. Additional mortalities

probably go unreported if the whales do not strand or are not thoroughly

necropsied.

5) Aboriginal harvest: The current International Whaling Commission (IWC) quota (for

1998-2002) allows for a harvest of 140 gray whales per year for local consumption by

aborigines (IWC 1998a).

5.1) Russian: From 1970 to 1998, an average of 139 gray whales were taken

annually along the coasts of the Chukotka Peninsula (Quan 1999, Brownell13). 

The Russian Federation has agreed to take no more than 135 whales annually from

1998 to 2002 (IWC 1998a).
-15-

14Pers. comm. Merrill Gosho, National Marine Mammal Lab, AFSC, NMFS, 7600 Sand Point Way NE,

Seattle, WA 98115-0070.

5.2) Alaskan: No gray whales have been allocated by the IWC to Alaskan Native

subsistence hunters since 1991 (Quan 1999). Two incidental takes of gray whales

by an Alaskan Native occurred in 1995 (Brownell13, Quan 1999).

5.3) Makah: The Makah Indian Tribe received a 5-year quota from the IWC in 1997

to harvest 20 gray whales for ceremonial and subsistence purposes. The Tribe may

harvest up to five gray whales per year from 1998 through 2002 (IWC 1998a,

Gearin 1999). Makah whalers struck and killed one gray whale on 17 May 1999

(Gosho14).

6) Review of potential research projects: As a part of the conclusions of the workshop,

it was recommended that the Eastern North Pacific stock of gray whales be monitored

for another 5-year period. This would occur between June 1999 and June 2004. 

Monitoring could provide information relevant to the regular reviews conducted by

NMFS (e.g., Hill and DeMaster 1998) and the IWC (e.g., IWC 1998b). The high

visibility of this stock along the west coast of North America has made it very popular,

so there is considerable public awareness and concern for the gray whales’ status. 

This stock’s annual migrations along highly populated coastlines and their

concentration in limited winter and summer areas may make them particularly

vulnerable to impacts from commercial or industrial development or local catastrophic

events. Also, the ease and efficiency of monitoring this stock during its migration past

shore stations has provided scientists a rare opportunity to document a large whale

species recovering from near extinction. Never before has there been as good an

opportunity to study life history parameters of a cetacean population approaching its

carrying capacity–a study which will be very beneficial to research on other, less

accessible whale stocks. The following list includes potential projects that will help in

this monitoring and further improve our understanding of the status of this whale

stock. Inherent in this research is the encouragement to keep open lines of

communication among scientists studying gray whales, which includes researchers in

Mexico, the United States, Canada, and Russia. 

6.1) Abundance and trends in abundance

6.11) Granite Canyon, California: NMML frequently conducts full-season

counts of gray whales during the southbound migration past this shore station

in central California (Shelden et al. in press). This has proven to be an optimal

site both logistically (easy access in an area with a relatively mild climate) and

biologically (where most of the gray whale population passes close to shore

each year). The census conducted at Granite Canyon has provided a longterm, consistent monitoring of stock abundance and trends (since 1968). 

Although this stock is not considered to be at risk, the continuation of the

seasonal counts will provide an ideal opportunity to study a large cetacean

population as it approaches carrying capacity. The Granite Canyon census is

considered to be a low risk investment as it is a system that has been well

tested. Further testing is needed to improve corrections for pod-size estimates,
-16-

continue studies of observer performance, and increase the accuracy of

statistical variances within the observation data. 

6.12) Point Vicente, California: Every year, ACS/LA volunteers conduct fullseason counts of both the southbound and northbound migrations past Point

Vicente, near Los Angeles (Schulman-Janiger 1999a) . These counts have

been collected consistently since 1984 and are beneficial to time-series

analyses; however, only a portion of the population passes this site during the

southbound and northbound migrations.

6.13) Yaquina Head, Oregon: A volunteer from Oregon State University

conducted counts of gray whales at Yaquina Head, near Newport, Oregon, in

the 1998/99 season (Mate and Poff 1999). This site was also used for counts

of the southbound and northbound migrations in 1978-81 (Herzing and Mate

1984).

6.14) Other sites: NMFS has no plans for systematic counts at locations other

than Granite Canyon since this has proven to be the best site for shore-based

counts.

6.141) Cape Sarichef, Alaska: Cape Sarichef, on the west edge of Unimak

Island, is an ideal location for studying the gray whale migration in and out

of the Bering Sea. This site was used for gray whale counts during several

southbound and northbound migrations in the 1970s (e.g., Rugh 1984). 

However, the U.S. Coast Guard no longer maintains a facility there,

making it logistically impractical to conduct research. 

6.142) Narrow Cape, Kodiak Island, Alaska: Narrow Cape, on the south

side of Kodiak Island, is an accessible site with a good view of the

migratory corridor in the area, but gray whales also migrate on the north

side of Kodiak Island, so the portion of the population passing Narrow

Cape each year is unknown. No full-season counts have been conducted

from this site. 

6.15) Stock assessment: NMFS conducts an assessment of the Eastern North

Pacific stock of gray whales at least every 3 years (Hill and DeMaster 1998);

the stock assessment is currently being updated. The IWC conducts

comprehensive assessments of stocks before harvest quotas are set (IWC

1998b); the next gray whale assessment will be in 2003.

6.16) Stock identification and discreteness: Genetic analysis may provide

information on the degree of genetic variety within the Eastern North Pacific

gray whale stock as well as determine differences between this stock and the

Western North Pacific (Korean) stock (e.g., Rosel and Kocher 1997). Genetic

discreteness of summering populations may be a factor in management

decisions (Darling et al. 1998), specifically with regard to the whales in

northwestern Washington where Makah Indians are whaling.

6.2) Population health and viability

6.21) Calf counts

6.211) Granite Canyon, California: The whale counts conducted by NMML

at Granite Canyon during the southbound migration include counts of

calves (Shelden et al. in press).
-17-

6.212) Piedras Blancas, California: During the past several years, the

NMFS Southwest Fisheries Science Center (SWFSC) has conducted shorebased counts of gray whale calves during the northbound migration

(Perryman et al. 1999b). Sighting rates at Piedras Blancas are compared to

abundance estimates made by NMML during the southbound migration.

6.213) Point Vicente, California: The ACS/LA chapter includes calf counts

in their ongoing effort at Point Vicente. The results show the percentage

of calves seen during both the southbound and northbound migrations

(Schulman-Janiger 1999b).

6.214) Baja California Sur: Counts of calves will continue to be a part of the

studies of gray whales in Baja California Sur (e.g., Urbán et al. 1997).

6.22) Condition index: Photogrammetric studies conducted by the SWFSC help

provide data on number of pregnant whales, proportion of sightings with

calves, and lengths and other dimensions of whales. Dimension data can

indicate animal health as a function of fat reserves (Perryman and Lynn 1999).

6.23) Biological sampling

6.231) Harvest: Data from harvested whales can help establish pregnancy

rates and indicate health of individuals (e.g., Reilly 1992, Blokhin in

press c).

6.232) Natural mortality: Samples from stranded whales may provide

information on biological parameters, including reproductive condition,

age, length, contaminant loads, stock discreteness, types of parasites or

diseases, and cause of death (e.g., Heyning and Dahlheim in press).

6.3) Distribution and habitat use

6.31) Baja California Sur: Proposed studies include photo-identification of

individual whales, radio-telemetry, and satellite-tagging. Results will provide

information on persistence and consistency of use of certain lagoons. There

was an intense study in 1980-85 that involved several of the lagoons (e.g.,

Jones and Swartz 1984). A multi-dimensional study over another 5-year

period would provide a valuable comparison to the previous research.

6.32) Washington State: Photo-identification studies conducted by Cascadia

Research Collective and the NMML (e.g., Calambokidis and Quan 1999,

Gosho et al. 1999a, 1999b) provide information on how often individual

whales are found in areas around northwestern Washington. This research will

help answer questions about the “resident” vs. “transient” whales in the area

where Makah Indians hunt whales.

6.33) Migration and foraging 

6.331) Satellite tagging: Satellite tagging of gray whales would provide

information on the timing and location of whales during their northbound

migration and where they spend time feeding.

6.332) Distribution information: Distribution data may be collected from a

variety of marine mammal surveys, such as the NMML cetacean surveys

across southern Alaska, observations on fisheries research cruises, records

collected in the Platforms of Opportunity Program, etc.
-18-

6.333) Migratory timing: Migratory timing can be documented through

shore-based observations at sites used in the past, such as Point Vicente,

Granite Canyon, and Yaquina Head (Rugh et al. 1999a, 1999b). 

6.34) Summer distribution: Aerial and/or vessel surveys may provide

information on current gray whale use of historic feeding grounds in the Bering

and Chukchi Seas. Oceanographic sampling could document potential changes

in prey production and availability (e.g., Grebmeier and Barry 1991). 

6.4) Anthropogenic concerns

6.41) Contaminant loads: Contaminant loads are documented by the NMFS

Northwest Fisheries Science Center (NWFSC) from samples collected from

strandings and biopsies (Tilbury et al. 1999). 

6.42) Oil spills and post-spill monitoring: There is a need for an oil-spill

response protocol to minimize the effects of oil spills on gray whales. To

develop this protocol, experimental designs are needed to minimize impacts of

oil spills and better understand the risks to gray whales relative to different

locations and intensities of oil spills.

6.43) Noise: Peter Tyack (Woods Hole Oceanographic Institute) and Chris Clark

(Cornell University) have recently conducted and will probably continue to

conduct acoustic studies relative to the response of large cetaceans, including

gray whales, to Low Frequency Active (LFA) underwater transmissions

(Tyack and Clark 1998).

6.44) Fishery interactions: The degree of impact of commercial and recreational

fisheries on gray whales may be assessed through examinations of stranded

whales, permit reports, and ships’ log books. In particular, more information is

needed from Mexico and Canada.

6.45) Commercial development in critical habitats

6.451) Salt extraction in Baja California Sur: A large salt evaporation

facility is proposed for San Ignacio Lagoon (SEMARNAP 1997). If this

facility is developed, the impact on whales using this lagoon should be

studied. A comparison could be made between potential impacts of

proposed salt work developments in Baja California Sur and the observed

impacts of northwestern Australian salt works on humpback whales.

6.452) Oil and gas exploration and extraction: Oil and gas exploration and

extraction have the potential of impacting whales along much of the

migratory route, including feeding areas in the Bering and Chukchi Seas.

6.453) Coastal development: Coastal development, and the concomitant

increase in human activities offshore, along much of the western shores of

Mexico, the United States, and Canada has the potential of adversely

impacting gray whales along their migration route (Moore and Clarke in

press). 

6.46) Whale watching

6.461) Regulations: A monitoring system should be established for operators

of whale watching vessels; for example, through permit reports and/or log
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books. The IWC has established a subcommittee to provide guidelines for

whale watching (IWC 1997d).

6.462) Studies: Studies should be conducted to evaluate the impact of whale

watching operations. Whales and boats could be tracked using theodolites

based on strategic shore-based sites. In Bahía Magdalena and San Ignacio

Lagoon there are ongoing studies of whale watching operations (PérezCortés Moreno8

, Sánchez Pacheco 1997b)

6.463) Photographs: Whale watching operations can be a source of

photographs that may be used to identify individual whales. This could be

beneficial in determining the amount of time individual whales stay in an

area relative to the number of boats.

6.47) Strandings: Currently there are stranding networks in the United States and

Mexico. On the U.S. West Coast, stranding information is collected by the

NMFS Alaska Regional Office in Alaska, Northwest Regional Office in

Washington and Oregon, and Southwest Regional Office in California. 

Besides aerial and vessel surveys of the lagoons in Mexico (Pérez-Cortés

Moreno 1999), there is an ongoing research project in Scammon’s Lagoon

(Pérez-Cortés Moreno8).

6.48) Ship strikes: The number of strikes can be partially recorded through

adequate documentation of marks on stranded whales and through ship logs

(e.g., Hill 1999c, Heyning and Dahlheim in press).

6.5) Research priorities: Workshop participants were asked to select the five

research projects that they would consider to be of the highest priority in

evaluating the status of the Eastern North Pacific stock of gray whales. Preference

was given to (in order of priority): 

1) survey of the southbound migration at Granite Canyon (Section 6.11); 

2) studies in the lagoons (Section 6.214, 6.31, 6.451, 6.453, 6.462, and 6.47); 

3) photogrammetry/condition index (Section 6.22, 6.31, and 6.32); 

4) calf counts (Section 6.21); and 

5) Bering and Chukchi Sea surveys of foraging habitat/regime shifts (Section 6.34).

Summary

The workshop convened by NMFS at NMML in Seattle, Washington, on 16-17 March

1999, culminated the review of the status of the Eastern North Pacific stock of gray

whales. This review was based on research conducted during the 5-year period following

the delisting of this stock and includes information collected through 16 June 1999. The

workshop followed guidelines outlined in the NMFS 5-year Plan to conduct the status

review and recommend whether to: 1) continue the monitoring program for an additional

5-year period; 2) terminate the monitoring program; or 3) consider changing the status of

the gray whale under the ESA. The 28 invited participants determined that this stock was

neither in danger of extinction, nor was it likely to become endangered within the

foreseeable future, according to the determining factors listed in section 4(a)(1) of the

ESA. Therefore, there was no apparent reason to reverse the previous decision to remove

this stock from the List. 
-20-

Canada’s Committee on the Status of Endangered Wildlife in Canada lists the

“Northeast Pacific population” of gray whale as “not at risk.” This is the lowest category

for animals in their classification system, which also includes vulnerable, threatened,

endangered, extirpated, or extinct.

The status of the Eastern North Pacific stock does not in any way alter the status of

the still-endangered Western North Pacific (“Korean”) stock of gray whales. 

There was a consensus among the workshop participants that the Eastern North

Pacific stock of gray whales should be monitored for an additional 5-year period (1999-

2004), especially as this stock may be approaching its carrying capacity. Monitoring

should include a continuation of surveys at Granite Canyon during the southbound

migration; collaborative research with Mexican scientists on phenology of gray whales and

the use of the lagoons in Baja California Sur; photogrammetry as a study of whale

condition; calf counts; and an examination of the affect of environmental parameters,

especially climate warming, on the whales’ use of foraging areas.

Although the Eastern North Pacific stock of gray whales no longer receives protection

under the ESA, it continues to be protected under the MMPA. As required by the

MMPA, NMFS conducts an assessment of this stock every 3 years, or when new

information becomes available. The last assessment occurred in 1997 (Hill and DeMaster

1998); it is currently being updated. Subsistence take is managed under quotas set by the

IWC. Comprehensive assessments of gray whales are conducted by the IWC before

quotas are set; the last assessment occurred in 1997 (IWC 1998b); the next will be in 2003

(IWC 1999a). There is no allowable commercial take of any gray whales, and the

Convention on the International Trade in Endangered Species (CITES) regulates the

transportation of animal parts. Furthermore, if there is evidence of a significant negative

decline and research indicates that such a change would be warranted, this stock can be

proposed to be listed again as threatened or endangered under the ESA.

This status review concludes the 5-year assessment of the Eastern North Pacific stock

of gray whales (required by section 4(g)(1) of the ESA) that commenced on 16 June 1994

(59 FR 31094) when this stock was removed from the List.

Acknowledgments

Funding for travel to the workshop was provided by the NMFS Office of Protected

Resources. Doug DeMaster was the chair for the workshop. Scientists making

presentations at the workshop included: Héctor Pérez-Cortés Moreno, Lorenzo Rojas

Bracho, and Jorge Urbán Ramírez from Mexico; Alisa Schulman-Janiger, from the

American Cetacean Society/LA Chapter; John Calambokidis from Cascadia Research

Collective; Jen Quan from the University of Washington; Bruce Mate from Oregon State

University; Bob Brownell, Meghan Donahue, and Wayne Perryman from the NMFS

Southwest Fisheries Science Center; John Stein and Gina Ylitalo from the NMFS

Northwest Fisheries Science Center; and Jeff Breiwick, Marilyn Dahlheim, Doug

DeMaster, Pat Gearin, Merrill Gosho, Scott Hill, Rod Hobbs, Sue Moore, Dave Rugh,

and Kim Shelden from the NMFS Alaska Fisheries Science Center (National Marine

Mammal Laboratory). Rod Hobbs provided the initial outline for the potential research

projects. Helpful guidance at the workshop was provided by Greg Silber from the NMFS

Office of Protected Resources, Steve Swartz from the NMFS Southeast Fisheries Science
-21-

Center, and Judy Zeh from the University of Washington. Greg Donovan, Helen Sharp,

and staff of the International Whaling Commission provided abstracts of manuscripts from

the IWC Journal of Cetacean Research and Management Special Issue 2 (in press) on gray

whales. We are grateful to Ken Hollingshead and Greg Silber for their careful review of

the Background section. Gary Duker and James Lee, of the AFSC Publications Unit,

provided formatting edits. This document was improved by review comments from

Héctor Pérez-Cortés Moreno, Lorenzo Rojas Bracho, Jorge Urbán Ramírez, José Sánchez

Pacheco, Alisa Schulman-Janiger, Kim Shelden, Rod Hobbs, Tom Loughlin, and Steve

Swartz.
-22-

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Weitkamp, L.A., R.C. Wissman, C.A. Simenstad, K.L. Fresh, and J.G. Odell. 1992. Gray

whale foraging on ghost shrimp (Callianassa californiensis) in littoral sand flats of

Puget Sound, U.S.A. Can. J. Zool. 70:2275-2280.

Weller, D.W., B. Würsig, A.L. Bradford, A.M. Burdin, S.A. Blokhin, H. Minakuchi, and

Brownell, R.L., Jr. In press. Gray whales (Eschrichtius robustus) off Sakhalin Island,

Russia: Seasonal and annual patterns of occurrence. Mar. Mammal Sci. 15(4).

Williams, T. 1998. Back from the brink. Audubon 100(6):70-77.

*Withrow, D.E. In press. Aerial surveys of gray whales along the central California coast

during the 1988, 1993 and 1994 southbound migrations. J. Cetacean Res. Manage.

Special Issue 2. (SC/A90/G3).

Withrow, D.E., R.C. Hobbs, and K.E.W. Shelden. 1993. Offshore distribution of gray

whales along the central California coast during the 1992-93 southbound migration. 

Unpubl. doc. SC/45/AS3 submitted to Sci. Comm. of Int. Whal. Commn. 10 p.
-36-

Withrow, D.E., J.L. Laake, and K.E.W. Shelden. 1994. Offshore distribution of gray

whales along the central California coast during the 1993-94 southbound migration.

Unpubl. doc. SC/46/AS8 submitted to Sci. Comm. of Int. Whal. Commn. 9 p.

Zemsky, V.A., L.S. Bogoslovskaya, R.G. Borodin, and I.V. Smelova. 1999. Whaling of

gray whales in the northern part of the Pacific Ocean and needs of the native

population of Chukotka for food whale products in 1997-1998. Unpubl. doc.

SC/51/AS29 submitted to Sci. Comm. of Int. Whal. Commn. 24 p.

Zhu, Q., and Y. Haidong. 1998. Strandings and sightings of the western Pacific stock of

the gray whale (Eschrichtius robustus) in Chinese coastal waters. Unpubl. doc.

SC/50/AS5 submitted to Sci. Comm. of Int. Whal. Commn. 4 p.
APPENDIX A

PARTICIPANTS AT THE WORKSHOP 

TO REVIEW THE STATUS OF 

THE EASTERN NORTH PACIFIC STOCK OF GRAY WHALES

16-17 March 1999

At the National Marine Mammal Laboratory, Seattle, Washington

Participants Affiliation and address Attended

Will Anderson PAWS

2122 8th Ave N, 201, Seattle, WA 98109

Yes

Mike Barber Seattle Post-Intelligencer

101 Elliott Ave. W, Seattle, WA 98119

Yes

Howard Braham** NMML, AFSC, NMFS (retired)

800 Acorn Circle, P.O. Box 1064, Ashland, OR 97520

No

Jeff Breiwick** NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Robert Brownell, Jr.** SWFSC, NMFS

P.O. Box 271, La Jolla, CA 92038

Yes

Steve Buckland* School of Mathematical and Computational Sciences

University of St. Andrews, North Haugh, St. Andrews

Fife, KY18 9SS, Scotland, UK

No

John Calambokidis* Cascadia Research Collective

218 1⁄2 W 4th Ave, Olympia, WA 98502

Yes

Leigh Calvez naturalist Yes

Marilyn Dahlheim** NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Jim Darling* West Coast Whale Research

P.O. Box 384, Tofino, BC, V0R 220 Canada 

No

Doug DeMaster**

(Chair)

NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Meghan Donahue* SWFSC, NMFS

P.O. Box 271, La Jolla, CA 92038

Yes

Toni Frohoff Humane Society of the US

321 Highschool Rd, 374 Bainbridge Island, WA 98110 

Yes

Pat Gearin* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes
-38-

Participants Affiliation and address Attended

Leah Gerber* National Center for Ecological Analysis and Synthesis

Marine Science Institute

University of California at Santa Barbara

735 State Street, Suite 300, Santa Barbara, CA 93101

No

Merrill Gosho* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

John Heyning* Section of Mammals

Natural History Museum of LA County

900 Exposition Blvd., Los Angeles, CA 90007

No

Scott Hill* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Rod Hobbs* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Robert Hofman* Marine Mammal Commission

4340 East-West Hwy, Room 905, Bethesda, MD 20814

No

Ken Hollingshead** Office of Protected Resources, NMFS 

1315 East-West Hwy, Silver Spring, MD 20910-3282

No

Susan Jordan* League for Coastal Protection

sjordan51@aol.com

No

Steve Katona* College of the Atlantic

Bar Harbor, ME 04609

No

Jeff Laake** NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Bruce Mate* Oregon State University

Mark O. Hatfield Marine Science Center

Newport, OR 97365

Yes

Sue Moore* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Marcia Muto* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Stephanie Norman NMFS Contractor, DVM

1223 Spring St. #400, Seattle, WA 98104

Yes

Héctor Pérez-Cortés

Moreno*

Instituto Nacional de la Pesca, CRIP

Km 1 Carretera a Pichilingue

La Paz, B.C.S., 23020 México

Yes

Wayne Perryman* SWFSC, NMFS

P.O. Box 271, La Jolla, CA 92038

Yes
-39-

Participants Affiliation and address Attended

Brenda Peterson Journalist 

MermaidInk@aol.com

Yes

Jennifer Quan* Cascadia Research

2181⁄2 W 4th Ave, Olympia, WA 98501

jquan@u.washington.edu

Yes

Randy Reeves* 27 Chandler Lane

Hudson, QC, J0P 1H0 Canada

No

Steve Reilly** SWFSC, NMFS

P.O. Box 271, La Jolla, CA 92038

No

Lorenzo Rojas Bracho* Bahía Vizcaíno 476, Col. Moderna

Ensenada, BC, 22860 México

 or

PMB-8132

4492 Camino de la Plaza

San Ysidro, CA 92173-3097 

Yes

Dave Rugh* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

José Sánchez Pacheco* Reserva de la Biosfera “El Vizcaíno”

Instituto Nacional de Ecología SEMARNAP

A.P. #65 Guerrero Negro

Baja California Sur, C.P., 23940 México 

jasanpa@compuserve.com

No

Alisa Schulman-Janiger* American Cetacean Society, Los Angeles Chapter

2716 S. Denison, San Pedro, CA 90731

Yes 

Joe Scordino NMFS/FMD

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Kim Shelden* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Greg Silber* Office of Protected Resources, NMFS 

1315 East-West Hwy, Silver Spring, MD 20910-3282

Yes

John Stein** NWFSC, NMFS

2725 Montlake Blvd. E., Seattle, WA 98112-2097

Yes

Steve Swartz** SEFSC, NMFS

75 Virginia Beach Dr, Miami, FL 33149

Yes

Grant Thompson** REFM, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes
-40-

Participants Affiliation and address Attended

Cynthia Tynan NWFSC, NMFS

Estuarine and Ocean Ecology Program

2725 Montlake Blvd. E., Seattle, WA 98112-2097

Yes

Jorge Urbán Ramírez* Departamento de Biologia Marina, UABCS

Programa de Investigacion de Mamiferos Marinos

Departamento de Biologia Marina

Universidad Autonoma de Baja California Sur

Ap. Post. 12-B La Paz, B.C.S., 23081 México

Yes

Paul Wade* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

No

Janice Waite* NMML, AFSC, NMFS

7600 Sand Pt Way NE, Seattle, WA 98115-0070

Yes

Gina Ylitalo* NWFSC, NMFS

2725 Montlake Blvd. E., Seattle, WA 98112-2097

Yes

Judy Zeh* University of Washington, Statistics

Box 354322, Seattle, WA 98195-4322

Yes

 *Invited or asked to review workshop material.

**Invited and member of the Gray Whale Monitoring Task Group in 1990.
APPENDIX B

ABSTRACTS

Agenda Section 1.11

PRELIMINARY ESTIMATES OF POPULATION SIZE OF GRAY WHALES

FROM THE 1992/93 AND 1993/94 SHORE-BASED SURVEYS

J.L. Laake,1 D.J. Rugh,1 J.A. Lerczak1, and S.T. Buckland2

1National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA 

2 School of Mathematical and Computational Sciences, St. Andrews University

North Haugh, St. Andrews, Fife KY16 9SS, Scotland, UK

Laake, J.L., D.J. Rugh, J.A. Lerczak, and S.T. Buckland. 1994. Preliminary estimates of population size

of gray whales from the 1992/93 and 1993/94 shore-based surveys. Unpubl doc. SC/46/AS7 submitted

to Sci. Comm. of Int. Whal. Commn. 13 p.

The California stock of gray whales (Eschrichtius robustus) has been recently proposed

for removal from the U.S. list of endangered and threatened species. As part of the delisting regulation under the U.S. Endangered Species Act, the National Marine Fisheries

Service has begun a monitoring effort that has included shore-based surveys conducted 10

December 1992 to 7 February 1993 and 10 December 1993 to 18 February 1994, during

the whales' southbound migration past Carmel, California. Survey methods were the same

as those used in previous seasons. Paired, independent counts were made whenever

possible but not during every watch as occurred in 1987/88. In total, 1,180 pods (2,112

whales) were recorded during 343 hours of watch from the main (south) observation site

when visibility was classified as excellent to good in 1992/93, and 1,864 pods (3,411

whales) were recorded during 447 hours in 1993/94. The survey data were analyzed using

methods consistent with those used in the 1987/88 data analysis. The population estimate

from the 1992/93 survey is 17,674 (CV = 5.87%, 95% confidence interval, 15,800 -

19,800), which is significantly lower than the 1993/94 estimate of 23,109 (CV = 5.42%,

95% confidence interval, 20,800 - 25,700) (z = -3.36, P = 0.0004). Possible reasons for

the difference are: 1) changes in the number of whales migrating as far south as Carmel;

2) poor sighting conditions in 1992/93, particularly during the peak of the migration; 3)

missing sources of variation. The 1993/94 estimate is not significantly different than the

1987/88 estimate of 20,869 (CV = 4.37%) (z = 1.46, P = 0.072).
-42-

Agenda Section 1.12

ABUNDANCE OF GRAY WHALES IN THE 1995/96 

SOUTHBOUND MIGRATION 

IN THE EASTERN NORTH PACIFIC

R.C. Hobbs, D.J. Rugh, J.M.Waite, J.M. Breiwick and D.P. DeMaster

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Hobbs, R.C., D.J. Rugh, J.M. Waite, J.M. Breiwick, and D.P. DeMaster. In press. Abundance of gray

whales in the 1996/96 southbound migration in the eastern North Pacific. J. Cetacean Res. Manage.

Special Issue 2.

Systematic counts of gray whales (Eschrichtius robustus) were conducted from 13

December 1995 to 23 February 1996 at Granite Canyon, California. This study is the

second of three during the 5-year period following the removal of gray whales from the

U.S. government list of endangered and threatened wildlife. The counts were made at the

same research station used most years since 1975 by the National Marine Mammal

Laboratory to observe the southbound migration of the eastern North Pacific stock. 

Counting methods were kept similar to those used in previous surveys and included

double counting to assess observer performance. In addition, aerial surveys and highpowered binoculars provided documentation that a negligible fraction of migrating whales

passed beyond the sighting range of the counting observers. A total of 2,151 pods (3,928

whales) was counted during 472.7 hours of standard watch effort with a visibility recorded

as fair to excellent. Data analysis procedures were substantially the same as in previous

years with a modification to account for differential sightability by pod size. Population

size is estimated to be 22,263 whales (CV = 9.25%; 95% log-normal CI = 18,700 to

26,500). This estimate is similar to the previous estimate of 23,109 (CV = 5.42%; 95%

CI = 20,800 to 25,700) from the 1993/94 survey.
-43-

Agenda Section 1.13

1.14

THE ABUNDANCE OF GRAY WHALES IN THE 1997/98 SOUTHBOUND

MIGRATION IN THE EASTERN NORTH PACIFIC 

Roderick C. Hobbs and David J. Rugh

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Hobbs, R.C., and D.J. Rugh. 1999. The abundance of gray whales in the 1997/98 southbound migration in

the eastern North Pacific. Unpubl. doc. SC/51/AS10 submitted to Sci. Comm. of Int. Whal. Commn.

18 p. 

Systematic counts of gray whales (Eschrichtius robustus) were conducted from 13

December 1997 to 24 February 1998 at Granite Canyon and Point Lobos, California. This

study is the third of three during the 5-year period following the removal of gray whales

from the U.S. government list of endangered and threatened wildlife. The counts were

made at the same research station used most years since 1975 by the National Marine

Mammal Laboratory to observe the southbound migration of the eastern North Pacific

stock of gray whales. Counting methods were kept similar to those used in previous

surveys and included double counting to assess the performance of observers. In addition,

high-powered binoculars provided documentation that a negligible fraction of migrating

whales passed beyond the sighting range of the counting observers. In total, 2,318 pods

(3,643 whales) were counted during 435.3 hours of standard watch effort when visibility

was recorded as fair to excellent. Data analysis procedures were substantially the same as

those used in previous years and identical to those used for the 1995/96 census. The

population is estimated to be 26,635 whales (CV = 10.06%; 95% log-normal confidence

interval = 21,878 to 32,427). This estimate is similar to the previous estimates of 23,109

(CV = 5.42%; 95% confidence interval = 20,800 to 25,700) from the 1993/94 survey and

22,263 whales (CV = 9.25%; 95% log-normal confidence interval = 18,700 to 26,500)

from the 1995/96 survey.
-44-

Agenda Section 1.14

PRELIMINARY DOCUMENTATION OF GRAY WHALE

ABUNDANCE ESTIMATION PROCEDURES 

J.M. Breiwick and R.C. Hobbs

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Breiwick, J.M., and R.C. Hobbs. 1996. Preliminary documentation of gray whale abundance estimation

procedures. Unpubl. doc. SC/48/AS2 submitted to Sci. Comm. of Int. Whal. Commn. 5 p.

The National Marine Mammal Laboratory (NMML) produces abundance estimates of the

Eastern North Pacific stock of gray whales based on counts made from Granite Canyon,

near Carmel, California. These abundance estimates are based on the number of pods

observed and the average recorded pod size obtained directly from the field data. These

numbers are corrected for 1) number of pods passing outside of count periods; 2) rate of

night travel; 3) pods missed within the viewing range of observers while on watch; and 4)

mean pod size. In conjunction with recent counts, aerial surveys have been flown to

compare the offshore distribution of gray whale sightings with the distribution based on

shore counts. Results since 1988 have indicated, however, that a correction factor for

whales passing beyond the viewing range of shore-based observers is not necessary. 

Aerial observations of pod size have been used in comparison with shore-based pod size

estimates to compute a correction factor for pod size bias. This document summarizes the

analytical procedures used during the past decade.
-45-

Agenda Section 1.15

DIEL VARIATION IN MIGRATION RATES 

OF EASTERN PACIFIC GRAY WHALES 

MEASURED WITH THERMAL IMAGING SENSORS

Wayne L. Perryman1, Meghan A. Donahue1, Jeffrey L. Laake2, and Thomas E. Martin1

1Southwest Fisheries Science Center, NMFS, NOAA

P.O. Box 271, La Jolla, CA 92037-0271, USA

2 National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Perryman, W.L., M.A. Donahue, J.L. Laake, and T.E. Martin. 1999a. Diel variation in migration rates of

eastern Pacific gray whales measured with thermal imaging sensors. Mar. Mammal Sci. 15(2):426-

45.

We recorded the blows of southbound gray whales from central California in January

1994, 1995, and 1996 using thermal imaging sensors. For our sampling purposes, we

defined day (0730-1630) and night (1630-0730) to coincide with the on/off effort periods

of the visual surveys being conducted concurrently. We pooled data across the three

years of sampling and tested for diel variation in respiration interval, pod size, offshore

distance, migration rate, and swimming speed by comparing paired day/night means for

samples collected within the same 24-hour period. We performed these tests using data

from the entire migration period and then repeated the tests for samples collected prior to

and after the approximate median migration date (January 15th). Over the entire

migration period we observed significantly larger daytime pod sizes (0day = 1.75 ± 0.280

km, noted here and throughout with one standard deviation, 0night = 1.63 ± 0.232km)

and offshore distances (0day = 2.30 ± 0.328 km, 0night = 2.03 ± 0.356 km), but found

no significant diel variation in respiration interval. For the entire migration period, the

nocturnal migration rate (average number of whales passing per hour) was significantly

higher (t = -2.65, 0 = 20, p = 0.02). During the early migration period, we detected no

significant diel variation in pod size or respiration interval, but daytime offshore distances

were significantly larger (0day = 2.28 ± 0.273 km, 0night = 1.96 ± 0.318 km). Diurnal

and nocturnal migration rates prior to January 15th were not significantly different. 

During the late migration period, there was no significant diel variation in respiration

interval, pod size, or distance offshore, but the nocturnal migration rate was significantly

higher (28%, SE = 11.6%) than the diurnal rate. We found no significant diel variation in

swimming speed in any comparison. We propose later migrants socialize more during the

day, which effectively slows their diurnal rate of migration even though they maintain

equal speeds day and night when swimming.
-46-

Agenda Section 1.2111

EVALUATION OF HIGH-POWERED BINOCULARS 

TO DETECT INTER-YEAR CHANGES 

IN THE OFFSHORE DISTRIBUTION OF GRAY WHALES 

David J. Rugh, James A. Lerczak, Roderick C. Hobbs, 

Janice M. Waite, and Jeffrey L. Laake

 National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

 7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Rugh, D.J., J.A. Lerczak, R.C. Hobbs, J.M. Waite, and J.L. Laake. In press. Evaluation of high-powered

binoculars to detect inter-year changes in the offshore distribution of gray whales. J. Cetacean Res.

Manage. Special Issue 2.

Paired, independent searches for gray whales (Eschrichtius robustus) were conducted

through fix-mounted, 25-power binoculars during January 1995 and 1996 at Granite

Canyon, California. This study was a test of an efficient method for documenting interyear changes in the offshore component of the gray whale migration. The research site

has been used most years since 1975 by the National Marine Mammal Laboratory to make

gray whale counts for abundance estimates. Matching sightings between these paired

observation efforts showed a very high agreement between observers (detection

probability 0.97) for whale groups consisting of more than one animal within 1 to 3 nmi of

shore, and a fairly high agreement (0.87) for animals that appeared to be traveling alone

(5% of the sampled population) within 1 to 3 nmi of shore. Therefore, sighting probability

remained high out to 3 nmi, a distance which includes most (98.7%) of the whale

migration. For the critical sighting range of 1 to 3 nmi, the method we applied here, using

paired, fix-mounted binoculars, is considered a feasible, cost-effective technique for

detecting inter-year differences in the offshore tail of the distribution of gray whales.
-47-

Agenda Section 1.2112

COMPARISON OF THE OFFSHORE DISTRIBUTION OF SOUTHBOUND

MIGRATING GRAY WHALES FROM AERIAL SURVEY DATA 

COLLECTED OFF GRANITE CANYON, CALIFORNIA, 1979-96

Kim E.W. Shelden and Jeffrey L. Laake

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Shelden, K.E.W., and J.L. Laake. In press. Comparison of the offshore distribution of southbound

migrating gray whales from aerial survey data collected off Granite Canyon, California, 1979-96. J.

Cetacean Res. Manage. Special Issue 2.

Aerial surveys provide an assessment of the offshore distribution of gray whales and an

estimate of the proportion of whales that migrate beyond the visual range of shore-based

observers. Six surveys were conducted concurrent with shore-based surveys during 1979,

1980, 1988, 1993, 1994 and 1996. Annual differences were tested for in the distribution

of whales within an area 3 nmi north and south of Granite Canyon, and it was found that

the distributions within 3 nmi of the shore differed by year but the shifts in the distribution

were minor (<0.3 nmi). The inshore (<2.25 nmi) and offshore (>2.25 nmi) distribution of

gray whale pods did not differ significantly between survey years. An average of 4.76%

(SE = 0.85%) of the whale pods were observed beyond 2.25 nmi and only 1.28%

(SE = 0.07%) were observed beyond 3 nmi.
-48-

Agenda Section 1.2121

1.2124

THE SOUTHBOUND MIGRATION OF GRAY WHALES

WINTER 1998/99

Bruce R. Mate and Amy Poff

Oregon State University, Hatfield Marine Science Center

Newport, OR 97365, USA

Mate, B.R., and A. Poff. 1999. The southbound migration of gray whales, winter 1998/99. Unpubl. doc.

submitted to the Workshop to Review the Status of the Eastern North Pacific Stock of Gray Whales,

16-17 March 1999, Seattle, WA.

Alternate half-hour counts were made during the morning hours from 5 December through

mid-February from the Yaquina Head Lighthouse (162 feet above sea level). 

Observations were made on all fair-weather days (< Beaufort 4).

The first whale was sighted on 23 December and the peak passage of whales per hour

occurred 7 January. By comparison with previous data from the same site (1978/81:

Herzing and Mate 1984), the migration started 3 weeks later than normal and the

migratory population peaked 6 days later than the latest date.

Aerial surveys in early December showed a number of animals along the coast but not

moving consistently in southerly directions. Surveys closer to Christmas about 10 miles

offshore showed more animals beyond 5 miles than inside 5 miles. This was an unusual

distribution from efforts in previous years when most of the population was within 3 miles

of the coast. Despite periods of good weather, whales did not tend to come nearshore to

the degree experienced in previous years. In this study, 60% of the animals were 5 miles

or farther offshore and 20% of the animals were within 3 miles of shore judging from

lighthouse observations.
-49-

Agenda Section 1.2122

FIELD REPORT ON THE WINTER DISTRIBUTION OF GRAY WHALES

IN WASHINGTON WATERS, 1998/99

Kim E.W. Shelden, Jeffrey L. Laake, Patrick J. Gearin, 

David J. Rugh, and Janice M. Waite

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA.

Shelden, K.E.W., J.L. Laake, P.J. Gearin, D.J. Rugh, and J.M. Waite. 1999a. Field report on the winter

distribution of gray whales in Washington waters, 1998/99. Unpubl. doc. submitted to the Workshop to

Review the Status of the Eastern North Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

The winter distribution of gray whales along the Washington coast has been difficult to

characterize primarily because of low survey effort (due to poor surveying conditions). 

Aerial surveys were conducted during the months of November and December 1998 and

January 1999 between Cape Flattery and Carroll Island, Washington. Flights included a

coastal trackline extending from Cape Flattery (48E23' N, 124E44' W) to Carroll Island

(48E00' N, 124E43' W) and 8 east-west oriented transect lines spaced at 7.4 km intervals,

extending 55.6 km offshore. Survey flights were scheduled at 10-day intervals with

modifications to the schedule occurring when weather conditions were not optimal. Four

complete surveys and two partial surveys were flown between November 1998 and

January 1999 for a total of 19.5 on-effort hours and 40 transect lines. Four gray whale

pods (6 individuals) and two gray whale pods (2 individuals) were observed on offshore

transect lines and coastal tracklines, respectively. Distances off the Washington coast for

pods observed on transect ranged from 5.5 km to 47 km. One sighting of an extremely

rotund whale on 22 December suggests that pregnant animals continued to pass the

Washington coast late in December. No calves were seen. Other marine mammal

sightings included aggregations of humpback whales and Pacific white-sided dolphins

feeding in the survey area in November and early December. Based on this study and

other reports, it appears that gray whales are widely dispersed across the outer

continental shelf of Washington State during both migratory and non-migratory periods. 

Sightings indicate that some may migrate close to shore while others may be nearly 50 km

offshore. Gray whales were also observed within Washington State's inside waters during

the southbound migration period. Because gray whales utilize the inside waters and outer

coast throughout the year, determining when a "resident" becomes a "migrant" has been

based on migratory timing. Although migratory timing cannot be confirmed by the aerial

survey results reported here because too few whales were seen during the flights, it does

appear that the peak of the southbound migration passes through the area in early to

mid-January.
-50-

Agenda Section 1.2123

GRAY WHALE OBSERVATIONS 

FROM TATOOSH ISLAND, WASHINGTON, DECEMBER 1998

Bete Jones

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Jones, B. 1999. Unpubl. doc. submitted to the Workshop to Review the Status of the Eastern North Pacific

Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

Gray whales (Eschrichtius robustus) were surveyed from the tower of the Tatoosh Island

lighthouse from 30 November - 16 December 1998. The purpose of the study was to

determine the onset of the southbound migration of gray whales past Cape Flattery, the

most northwestern point of Washington State. Observations were conducted primarily

without the use of optical aids. 7 X 50 Fujinon binoculars, equipped with reticles and a

magnetic compass, were used to document sighting location. Gray whales were seen on

three occasions (2, 4, and 13 December) during 49.3 hours of observation effort over a

total of 12 days. The average daily observation effort for this time was 4.1 hours. The

maximum possible sighting distance was estimated at 25 km. Gray whales were seen at a

range of 0.6 - 5.9 km from shore. Although few migrating gray whales were observed

during this period, it is possible that whales passed offshore, out of the observer’s sighting

range. It is also possible that this time period (30 November - 16 December) represented

the very early stages of the southbound gray whale migration past Washington, thus few

whales were in the vicinity. Aerial and vessel surveys conducted by the National Marine

Mammal Laboratory in November and December 1998, and January 1999 support the

latter hypothesis.
-51-

Agenda Section 1.2124

SOUTHBOUND GRAY WHALE MIGRATION TIMING 

OFF LOS ANGELES, 1985-99

Alisa Schulman-Janiger

American Cetacean Society, Los Angeles Chapter

2716 South Denison Avenue, San Pedro, CA 90731, USA

Schulman-Janiger, A. 1999a. Southbound gray whale migration timing off Los Angeles, 1985-99.

Unpubl. doc. submitted to the Workshop to Review the Status of the Eastern North Pacific Stock of

Gray Whales, 16-17 March 1999, Seattle, WA.

TENTH PERCENTILE, MEDIAN DATES, AND NINETIETH PERCENTILE

FOR THE SOUTHBOUND GRAY WHALE MIGRATION

OFF PT. VICENTE/LONG POINT, CALIFORNIA, 1985-99

Season

number Census dates

10th percentile

Sightings (whales)

Median (50th

percentile)

Sightings (whales)

90th percentile

Sightings

(whales)

3 1 Dec 85 - 17 May 86 7 Jan (5 Jan) 30 Jan (29Jan) 20 Feb (18 Feb)

4 1 Dec 86 - 3 May 87 2 Jan (4 Jan) 28 Jan (28 Jan) 12 Feb (12 Feb)

5 1 Dec 87 - 14 May 88 5 Jan (5 Jan) 18 Jan (18 Jan) 5 Feb (5 Feb)

6 1 Dec 88 - 30 Jun 89 2 Jan (4 Jan) 15 Jan (17 Jan) 31 Jan (31 Jan)

7 1 Dec 89 - 6 Jun 90 1 Jan (1 Jan) 24 Jan (24 Jan) 11 Feb (11 Feb)

8 1 Dec 90 - 12 May 91 25 Dec (30 Dec) 19 Jan (19 Jan) 16 Feb (16 Feb)

9 1 Dec 91 - 3 May 92 2 Jan (3 Jan) 21 Jan (23 Jan) 14 Feb (14 Feb)

10 1 Dec 92 - 8 May 93 30 Dec (30 Dec) 18 Jan (16 Jan) 15 Feb (11 Feb)

11 1 Dec 93 - 7 May 94 3 Jan (5 Jan) 28 Jan (27 Jan) 15 Feb (14 Feb)

12 1 Dec 94 - 5 May 95 22 Dec (24 Dec) 17 Jan (18 Jan) 11 Feb (11 Feb)

13 1 Dec 95 - 10 May 96 30 Dec (31 Dec) 24 Jan (26 Jan) 17 Feb (16 Feb)

14 1 Dec 96 - 16 May 97 30 Dec (30 Dec) 18 Jan (18 Jan) 12 Feb (9 Feb)

15 1 Dec 97 - 15 May 98 1 Jan (2 Jan) 17 Jan (17 Jan) 9 Feb (5 Feb)

16 1 Dec 98 - 15 May 99 28 Dec (31 Dec) 21 Jan (22 Jan) 8 Feb (8 Feb)
-52-

Agenda Section 1.2124

1.213 

1.214 

TIMING OF THE SOUTHBOUND MIGRATION OF GRAY WHALES IN 1998/99

David J. Rugh1, Kim E.W. Shelden1, and Alisa Schulman-Janiger2

1National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

2

 American Cetacean Society, Los Angeles Chapter

2716 S. Denison, San Pedro, CA 90731, USA

Rugh, D.J., K.E.W. Shelden, and A. Schulman-Janiger. 1999a. Timing of the southbound migration of

gray whales in 1998/99. Unpubl. doc. submitted to the Workshop to Review the Status of the Eastern

North Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

The southbound migration of gray whales has been documented most seasons since 1967

from Granite Canyon, a shore-based observation station in central California. Prior to

1980, median dates of sightings ranged from 5-14 January, with an overall median date of

8 January. Since 1980, there has been a 1-week delay in the peak, such that the median

date is now closer to 15 January (ranging 12-19 January). Allowing for this delay, and

using a travel rate of 144 km/day between shore stations, expected peak dates in 1998/99

should have been 11 December for Cape Sarichef, at the tip of the Alaska

Peninsula/Unimak Island; 18 December for Narrow Cape near Kodiak, Alaska; 5 January

for Tatoosh Island, the northwesternmost tip of Washington State; 8 January for Yaquina

Head, near Newport, Oregon; 15 January for Granite Canyon, central California; and 18

January at Point Vicente, near Los Angeles, California. Although no observations were

made at Granite Canyon in 1998/99, sightings collected at Yaquina Head and Point

Vicente indicate that the southbound migration was within 3 days of the expected date. 

Inter-year variations of a few days in migratory dates may be explained in part by

variations in the median location of whales in the Bering or Chukchi Seas just prior to the

onset of the migration. The further north the whales are in late October, the shorter the

days will be (i.e., a perceived reduction in photoperiod), which seems to be the primary

cue to initiating the southbound migration.
-53-

Agenda Section 1.221

CETACEAN HABITATS IN THE ALASKAN ARCTIC

Sue E. Moore1 and Douglas P. DeMaster2

1Science Applications International Corporation

3990 Old Town Avenue, Suite 105A

San Diego, CA 92110-2931, USA

2National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Moore, S.E., and D.P. DeMaster. 1997. Cetacean habitats in the Alaskan arctic. J. Northwest Atl. Fish.

Sci. 22:55-69.

Marine mammals can be used as indicators of environmental productivity because they

must feed efficiently and therefore aggregate where prey is plentiful. Three species of

cetaceans, bowhead whales (Balaena mysticetus), gray whales (Eschrichtius robustus),

and white whales (Delphinapterus leucas) migrate to the Alaskan arctic each year to feed. 

These species have distinctly different feeding modes and forage at dissimilar trophic

levels. Bowhead whales filter zooplankton from the water column, gray whales siphon

infaunal crustaceans from the benthos and white whales catch a variety of nekton including

crustaceans, cephalopods and fishes.

Line transect aerial surveys were conducted over the Alaskan Chukchi and Beaufort Seas

each late summer and autumn 1982-91. The resulting database, consisting of 634 flights,

was post-stratified by survey type and sea state (Beaufort # 04) to provide a database of

cetacean sightings made along random transects during good survey conditions. Sightings

made during connect and search legs of the survey, and in rough seas were excluded. 

Post-stratification resulted in a cumulative (1982-91) database of 276,754 transect-km of

survey effort during which there were 554 bowhead, 608 gray and 831 white whale

sightings.

Habitat partitioning and variability in habitat use among cetaceans in offshore areas of

northern Alaska is poorly defined. Available data suggest that cetacean distribution and

abundance patterns can be quantified on the basis of water depth and surface ice cover,

and that these indices can be linked to large-scale oceanographic processes. In summer,

mean depth and percent surface ice cover were significantly different (p < 0.001) among

bowhead (900 m, 52%; n = 79), gray (40 m, 1%; n = 497) and white whales (1,314 m,

60%; n = 146). All pairs were significantly different (p < 0.003), except for bowheadwhite whale ice cover (p < 0.13). Similarly in autumn, mean depth and percent ice cover

were significantly different (p < 0.001) among bowhead (109 m, 22%; n = 475), gray
-54-

(38 m, 7%; n = 111) and white whales (652 m, 52%; n = 685); all pairs were significantly

different (p < 0.001). In addition, mean depth and percent ice cover were significantly

different (p < 0.001) between summer and autumn for bowhead and white whale sightings. 

Currents are bathymetrically driven, and ice cover influenced by currents and wind, in the

Chukchi and Beaufort Seas. The association of cetaceans with specific bathymetric and

ice cover regimes provides a foundation for further investigation of inter-specific habitat

selection, zones of productivity and insight to the role of cetaceans in Alaskan arctic

ecology.
-55-

Agenda Section 1.222

PHOTOGRAPHIC IDENTIFICATION RESEARCH ON SEASONAL RESIDENT

WHALES IN WASHINGTON STATE

John Calambokidis and Jennifer Quan

Cascadia Research

2181⁄2 W 4th Ave.

Olympia, WA 98501, USA

Calambokidis, J., and J. Quan. 1999. Photographic identification research on seasonal resident whales in

Washington State. Unpubl. doc. submitted to the Workshop to Review the Status of the Eastern North

Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

Photographic identification of gray whales in Washington State has been conducted by

Cascadia Research since 1984. This has been part of an ongoing research effort to study

the abundance, movements, residence times, and return rate of seasonal resident gray

whales that spend the spring, summer, and fall feeding in these areas. Starting in 1992,

surveys were more frequent and encompassed a broader region. Since 1996, this effort has

also included identifications from the National Marine Mammal Laboratory from

systematic surveys along the northern Washington Coast and western Strait of Juan de

Fuca. 

Through 1997, more than 600 identifications of whales have been made, representing 168

unique individuals. In 1996 and 1997, 47 and 37 different gray whales were identified

primarily on the northern coast of Washington State and near the western entrance to the

Strait of Juan de Fuca (both the Washington and Vancouver Island sides). Movements

among these three regions were very common and most animals were seen multiple times

(up to 11) over periods of up to 163 days. Of whales identified in northwest Washington

in 1996 and 1997, 64%-83% had been identified in a previous year. Gray whales identified

near Grays Harbor in the spring were less likely to have been seen multiple times (52%) or

a previous year (26%). Comparison of photographic catalogs with researchers working in

British Columbia revealed that many of the whales that feed along the Washington coast

through the summer range along the British Columbia coast to areas north of Vancouver

Island. Gray whale occurrence in Puget Sound has been more variable from year to year.

Analysis is currently underway of the 1998 sample which is the largest and most

comprehensive to date. Effort by Cascadia Research included surveys and identifications

off California, Oregon, several regions of Washington State (including Puget Sound),

southern British Columbia, and southeast Alaska. Photographs of animals in specific

regions within this range were also obtained by collaborating researchers with NMML,

West Coast Whale Research Foundation, Humboldt State University, University of

Victoria, University of British Columbia, Department of Fisheries and Oceans, Vancouver

Aquarium, Juan de Fuca Express, and Coastal Ecosystems Research Foundation. These
-56-

represent close to 500 records of over 150 different individuals. Preliminary results of this

analysis has provided new information on the status and movements of these seasonal

resident whales.

Overall conclusions include:

1. Seasonal resident gray whales utilize coastal areas from northern California to

southeast Alaska from spring to fall with some interchange of animals among most of

these areas.

2. Gray whales show some localized site fidelity to certain areas but also move widely

within and between years. Gray whales seen in northern Puget Sound show a strong

site fidelity to this area but only for part of the season and then move to other

unknown areas (not currently sampled).

3. Utilization of some areas, such as southern Puget Sound, are highly variable year to

year and whales seen in this area have a high mortality rate and are rarely seen in more

than one year.

4. The total number of seasonal resident animals is not known (in the hundreds), nor is

how they are recruited to this group, or the degree to which they need to be managed

as a separate unit.
-57-

Agenda Section 1.222

THE SUMMER AND FALL DISTRIBUTION OF GRAY WHALES 

IN WASHINGTON WATERS

 M.E. Gosho1, P.J. Gearin1, J. Calambokidis2,

 K.M. Hughes1, L. Cooke3, L. Lehman1, and V.E. Cooke3 

1National Marine Mammal Laboratory

 Alaska Fisheries Science Center, NMFS, NOAA

 7600 Sand Point Way NE, Bin C15700

 Seattle, WA 98115-0070, USA

2Cascadia Research Collective

 Waterstreet Building

 218 1⁄2 West Fourth Avenue

 Olympia, WA 98501, USA

3Makah Tribal Fisheries Management Division

 Makah Indian Nation

 P.O. Box 115

 Neah Bay, WA 98357

Gosho, M.E., P.J. Gearin, J. Calambokidis, K.M. Hughes, L. Cooke, L. Lehman, and V.E. Cooke. 1999a.

The summer and fall distribution of gray whales in Washington waters. Unpubl. doc. submitted

to the Workshop to Review the Status of the Eastern North Pacific Stock of Gray Whales, 16-17

March 1999, Seattle, WA.

The National Marine Mammal Laboratory has been studying gray whale distribution and

identification since 1996 in the Strait of Juan de Fuca, off the northern Washington coast,

and off the southwest coast of Vancouver Island. Each year the animals were

concentrated in different locations. In 1996, the largest concentration of gray whales

occurred off Portage Head and Makah Bay on the northern Washington coast. In 1997,

the majority occurred in the westernmost Strait of Juan de Fuca from Bullman Beach to

Mushroom Rock. In 1998, most of the gray whales were sighted off the southwest coast

of Vancouver Island. Photographs of gray whales allowed the identification of 18

individual animals in 1996 and 28 animals in 1997. Photo-identification and co-operation

with other researchers showed that gray whales moved freely between areas in the Strait

of Juan de Fuca, off the Washington coast, and off the southwest coast of Vancouver

Island. 
-58-

Agenda Section 1.23

GRAY WHALE STUDIES AT LAGUNA SAN IGNACIO,

B.C.S., MÉXICO, WINTER 1996

Jorge Urbán R., Alejandro Gómez-Gallardo U., Victor Flores de Sahagún,

Jessica Cifuentes L., Stephan Ludwig, and Miguel Palmeros R.

Departamento de Biología Marina, Universidad Autónoma de Baja California Sur

Ap. Post. 19-B, La Paz, B.C.S., 23081 México

Urbán R., J., A. Gómez-Gallardo U., V. Flores de Sahagún, J. Cifuentes L., S. Ludwig, and M. Palmeros

R. 1997. Gray whale studies at Laguna San Ignacio, B.C.S., México, winter 1996. Rep. Int.

Whal. Commn. 47:625-633.

Laguna San Ignacio, located on the west coast of the Baja California Peninsula, is one of

the four main calving-breeding lagoons of the eastern Pacific gray whale (Eschrichtius

robustus). Uncertainty exists concerning the potential effects of both whale watching and

the development of a proposed salt project on gray whales and the lagoon ecosystem. 

This note documents the current use of Laguna San Ignacio by gray whales for

comparison with previous studies and, as far as possible, to provide a baseline to detect

and analyse changes in the whales’ use of this lagoon. Twenty boat censuses were carried

out from 17 January to 27 March 1996. The maximum combined count was 207 (115

single whales and 92 cow-calf pairs). The peak numbers of both single whales and cowcalf pairs were at the same time in early March when almost 40% fewer whales were

observed in 1996 than the 1978-82 average. Density estimates at the maximum combined

count were: 8.6 whales/km2 in the lower zone, 3.8 whales/km2 in the middle zone and 1.3

whales/km2 in the upper zone. Of the 329 identified whales, 164 were singles, 141 cowcalf pairs and 24 undetermined; 51 whales were seen more than once (43 cow-calf pairs

and 8 singles). Different residency intervals were documented: cow-calf pairs stayed in

the lagoon 18.3 ± 4.8 (95% C.I.) days and single whales 2.6 ± 1 (95% C.I.) days. Four

systematic aerial surveys were carried out at Bahía Ballenas between 1 February and 4

March. The maximum count in this bay was on 28 February with 127 adult whales (119

single whales and 8 cow-calf pairs). These observations must be continued for a period of

years to establish a new basis for comparison with previous research results. Further

photographic and tagging studies may help in developing turnover rates, which will allow

the number of whales using the lagoon to be calculated, based on visual surveys.
-59-

Agenda Section 1.23

A NOTE ON THE 1997 GRAY WHALE STUDIES

AT LAGUNA SAN IGNACIO, B.C.S., MÉXICO

Jorge Urbán R., Alejandro Gómez-Gallardo U., and Miguel Palmeros R.

Departamento de Biología Marina, Universidad Autónoma de Baja California Sur

Ap. Post. 19-B, La Paz, B.C.S., 23081 México

Urbán R., J., A. Gómez-Gallardo U., and M. Palmeros R. 1998a. A note on the 1997 gray whale studies at

Laguna San Ignacio, B.C.S., México. Rep. Int. Whal. Commn. 48:513-516.

This note includes the results of our second year of gray whale studies at Laguna San

Ignacio, B.C.S., México. Uncertainty exists concerning the potential effects of both

whalewatching and the development of the proposed salt project on gray whales and the

lagoon ecosystem. The purpose of this report is to document the current use of Laguna

San Ignacio by the gray whales for comparison with previous studies. Eleven complete

censuses of the lagoon were done by boat to determine whale abundance and distribution

from 11 February to 29 March 1997. The maximum combined count was 253 (127 single

whales and 126 cow-calf pairs) during the last week of February. Six dead calves (four

males and two females) were found inside the lagoon. The upper zone of the lagoon was

the most important for cow-calf pairs and the lower zone for single whales. There were

22% more whales than in the 1996 winter season, but this is still 36% lower than the

highest count in 1985. Different residency intervals were documented: cow-calf pairs

stayed in the lagoon 19.6 ± 3.5 days (95% C.I.), and the single whales 6.2 ± 3.2 days

(95% C.I.). Nine whales photo-identified in 1996 were also photographed during the

1997 winter season.
-60-

Agenda Section 1.23

TRANSITO DE BALLENA GRIS (ESCHRICHTIUS ROBUSTUS) 

EN BAHÍA BALLENAS, BAJA CALIFORNIA SUR, MÉXICO

José Angel Sánchez Pacheco1 and José León Valdés Aragón

Reserva de la Biosfera “El Vizcaíno”

Instituto Nacional de Ecología SEMARNAP

A.P. #65 Guerrero Negro, Baja California Sur, C.P. 23940 México

Sánchez Pacheco, J.A., and J.L. Valdés Aragón. 1997. Transito de ballena gris (Eschrichtius robustus) en

Bahía Ballenas, Baja California Sur, México. [The transit of the gray whale (Eschrichtius

robustus) in Bahía Ballenas, Baja California Sur, Mexico.] Boletín Pesquero CRIP-La Paz 7:26-

33.

Results are presented on observations of the transit of gray whales at different distances

from the coast in Bahía Ballenas, Baja California Sur, during the 1996 and 1997 seasons. 

Whales that moved northwards prevailed (96%). There were fewer single whales in 1997

than in 1996; the reverse situation occurred in whales with calves. Single whales transited

further from the coast (75.4% $2 km) than whales with calves (82.32% within 3 km). 

The number of single whales estimated to migrate north from the observation point was

2,888 and 2,195 for 1996 and 1997, respectively. There were 418 cow/calf pairs seen in

1996 and 621 in 1997.

1Current address: A.P. #71, Guerrero Negro, Baja California Sur, C.P. 23940 México

E-mail: jasanpa@compuserve.com
-61-

Agenda Section 1.3

ESTIMATED TRENDS IN ABUNDANCE OF EASTERN PACIFIC GRAY

WHALES FROM SHORE COUNTS, 1967/68 TO 1995/96

S.T. Buckland1 and J.M. Breiwick2

1School of Mathematical and Computational Sciences

University of St. Andrews

North Haugh, St. Andrews, Fife, KY18 9SS, Scotland, UK

2

 National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

 7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Buckland, S.T., and J.M. Breiwick. In press. Estimated trends in abundance of eastern Pacific gray whales

from shore counts, 1967/68 to 1995/96. J. Cetacean Res. Manage. Special Issue 2. 

Estimates of abundance of eastern Pacific gray whales are obtained from counts made

during their southbound migration past a shore-based station near Monterey, California. 

Assuming an exponential rate of increase, the population is estimated to have increased at

2.5% per annum (SE = 0.3%) between 1967/68 and 1995/96. However, there is some

indication that the population growth is slowing, so that an asymptotic growth curve may

be more appropriate. The estimated asymptote from a logistic model is 26,046 (SE =

6,281) and the inflection point is approximately in 1971 (SE = 6.5). The onset of the

migration, when 10% of the whales have passed the station, has occurred increasingly

later through this sample period, by approximately one day every 2 years. Median dates

show a similar trend of roughly one day every 3 years. However, there is no significant

change in the date at which 90% of whales have passed the station.
-62-

Agenda Section 1.3

GRAY WHALE ABUNDANCE ESTIMATES, 1967/68 - 1997/98:

ROI, RY, AND K

J.M. Breiwick

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Breiwick, J.M. 1999. Gray whale abundance estimates, 1967/68 - 1997/98: ROI, RY and K. Unpubl. doc.

submitted to the Workshop to Review the Status of the Eastern North Pacific Stock of Gray

Whales, 16-17 March 1999, Seattle, WA.

Gray whale abundance estimates for the period 1967/68 to 1997/98 were fit using a

generalized linear model (Poisson error, logarithmic link), giving a rate of increase of

2.52% per annum (SE = 0.27%). In addition, a (continuous) logistic model fit to the data

gave a K (carrying capacity) of 37,364 (SE = 24,854), larger by 11,000 than a similar

estimate based on the 1967/68 - 1995/96 data. Both estimates have very large CVs

associated with them. A discrete logistic model was also used to estimate Rmax and K. A

replacement yield (RY) of 612 was calculated based on the rate of increase estimate,

average catches and the abundance estimates. A Monte Carlo procedure was used to

calculate a 95% confidence interval for RY.
-63-

Agenda Section 1.3

A BAYESIAN ANALYSIS OF EASTERN PACIFIC GRAY WHALE

POPULATION DYNAMICS

Paul R. Wade1 and Douglas P. DeMaster2

1Office of Protected Resources, National Marine Fisheries Service

c/o National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

 7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

2National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

 7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Wade. P.R., and D.P. DeMaster. 1996. A Bayesian analysis of eastern Pacific gray whale population

dynamics. Unpubl. doc. SC/48/AS3 submitted to Sci. Comm. of Int. Whal. Commn. 21 p.

A Bayesian statistical method was used to investigate the population dynamics of eastern

Pacific gray whales. Apparent stability in the three most recent abundance estimates may

be due to a density-dependent slowing of the population growth rate. This hypothesis was

tested by comparing how well density-dependent population models fit the data relative to

density-independent population models. Additionally, a second hypothesis was tested,

which was whether using a parameter representing additional variance in the abundance

estimates provided a better fit to the data than not including it. In total, the fit of eight

different models were compared through the use of the Bayes factor. Density-dependent

models were decisively supported by the data over density-independent models when the

additional variance term was not used. However, the use of the additional variance term

was also decisively supported by the comparisons. When the additional variance term was

included, the data still favored the density-dependent models, but only marginally. Point

estimates of the equilibrium population size ranged from 24,000 to 32,000 depending

upon which model was used, but values as high as 70,000 still had some probability.
-64-

Agenda Section 1.3

A BAYESIAN STOCK ASSESSMENT OF THE EASTERN PACIFIC GRAY

WHALE USING ABUNDANCE AND HARVEST DATA FROM 1967 TO 1996

Paul R. Wade

Office of Protected Resources, National Marine Fisheries Service, NOAA

c/o National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

 7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Wade. P.R. In press. A Bayesian stock assessment of the eastern Pacific gray whale using abundance and

harvest data from 1967 to 1996. J. Cetacean Res. Manage. Special Issue 2.

Abundance and harvest data since 1966/67 were used to assess the eastern Pacific stock of

gray whales. A Bayesian statistical method was used to estimate probability distributions

for the parameters of both a simple and an age and sex structured population dynamics

model, as well as output quantities of interest. Model comparisons using the Bayes Factor

provided conclusive evidence that an additional parameter should be used to account for

unexplained variation in the abundance time series. Incorporating the additional variance

parameter decreased the precision of the estimates of the other parameters. Point

estimates of carrying capacity ranged from 24,640 to 31,840 for the different models, but

the posterior distributions from the selected models were very broad and excluded few

values. The current depletion level (population size as a fraction of carrying capacity) was

estimated to be about 0.75, with a lower 2.5th percentile of 0.36. The probability that the

population was still below one-half of its carrying capacity was estimated to be 0.21, with

a corresponding probability of 0.28 that the population was still below its maximum

sustainable yield level. Quantities from which catch limits could potentially be calculated

were estimated, including current replacement yield, maximum sustainable yield and the

quantity Q1 (described in Wade and Givens 1997).
-65-

Agenda Section 1.41

GRAY WHALES ILLUSTRATE THE VALUE OF MONITORING DATA IN

IMPLEMENTING THE ENDANGERED SPECIES ACT

Leah R. Gerber1, Douglas P. DeMaster2, and Peter M. Kareiva1

1National Center for Ecological Analysis and Synthesis

University of California at Santa Barbara

735 State Street, Suite 300

Santa Barbara, CA 93101-3351, USA

2National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

 7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Gerber, L.R., D.P. DeMaster, and P.M. Kareiva. In press. Gray whales illustrate the value of monitoring

data in implementing the Endangered Species Act. Conserv. Biol.

Many scientists lament the absence of data for endangered species and argue that more

funds should be spent acquiring basic information regarding population trends. Using

nineteen years of abundance estimates for the eastern North Pacific gray whale

(Eschrichtius robustus), we sampled subsets of the original survey data to identify the

number of years of data required to remove the population from the Endangered Species

Act’s (ESA) List of Endangered and Threatened Wildlife. For any given duration of

monitoring, we selected all possible combinations of consecutive counts. To incorporate

variability in growth rates we extracted a maximum likelihood estimator of growth rate

and confidence interval about that growth rate on the assumption that the population

changes can be approximated by a simple diffusion process with drift. We then applied a

new approach to determine ESA status for each subset of survey data and found that a

quantitative decision to delist is unambiguously supported by eleven years of data, but

precariously uncertain with fewer than ten years of data. The data needed to produce an

unequivocal decision to delist gray whales cost the National Marine Fisheries Service an

estimated $660,000, a surprisingly modest expense given the fact that delisting can greatly

simplify regulatory constraints. This example highlights the value of population

monitoring in administering the ESA, and provides a compelling example of the utility of

such information in identifying both imperiled species and recovered species. The

economic value of such data should be clear: they provide the foundation for delisting,

which could ultimately save much more money than the collection of the data would ever

cost.
-66-

Agenda Section 2.1

GRAY WHALE CALF SIGHTINGS COLLECTED DURING 

SOUTHBOUND MIGRATIONS, 1952-95

Kim E.W. Shelden, David J. Rugh, and Sally A. Boeve1

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

 

Shelden, K.E.W., D.J. Rugh, and S.A. Boeve. In press. Gray whale calf sightings collected during

southbound migrations, 1952-95. J. Cetacean Res. Manage. Special Issue 2.

For the past 43 years, scientists at the National Marine Mammal Laboratory and preceding

organizations, have collected information on sightings of gray whale calves during the

whales' annual migration between Alaska and Mexico. The data document the timing and

location of calving during the southbound migration along the California coast. 

Calf-sighting data were collected by observers conducting abundance surveys of gray

whales from shore-based sites at Point Loma, near San Diego, in 1952-69 and 1975-78;

Yankee Point, Carmel, in 1967-74; and Granite Canyon, Carmel, during most years

between 1974 and 1995. Although some reporting methods have changed over the years,

all records indicate that observers searched for and recorded calves. In addition to

shore-based surveys, aerial surveys were conducted in five seasons between 1979 and

1994. Results indicate that shore-based observers missed 62% of the calves within their

viewing area (0-2.6 km from shore), suggesting that calves are significantly

under-represented in the shore-based data record. For many of the early census years

(1952-74), the percentage of calves sighted (number of calves/total whales) was within the

range 0.0-0.2%. In 1975 the percentage of calves sighted at Point Loma increased

substantially (to 0.7%) but it did not show up at the Carmel shore stations, 570 km north

of Point Loma, until 1984. The highest calf count (n = 36; 0.8%) occurred during

1993/94 at Granite Canyon, when migration dates were later than for any other year. The

apparent increase in calf sightings may be related to a trend towards successively later

migrations over the 43 year observation period, or to an increase in spatial and temporal

distribution of calving as the population has increased. As the population reaches carrying

capacity, food resources may be more limited, resulting in pregnant females departing

from the feeding grounds later and with reduced fat reserves. As a result, parturition may

be occurring prior to reaching the preferred calving grounds at Baja California, Mexico.

1Present address: 1415 - 2nd Ave., #2103, Seattle, WA 98101, USA.
-67-

Agenda Section 2.1

GRAY WHALE CALF SIGHTINGS 

DURING SOUTHBOUND MIGRATIONS, 1995-98

Kim E.W. Shelden and David J. Rugh

National Marine Mammal Laboratory

 Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

 Seattle, WA 98115-0070, USA

Shelden, K.E.W., and D.J. Rugh. 1999. Gray whale calf sightings during southbound migrations,

1995-98. Unpubl. doc. submitted to the Workshop to Review the Status of the Eastern North

Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

As an addendum to Shelden et al. (in press), this report provides data on sightings of gray

whale calves that were collected during aerial surveys conducted in January 1996 and

shore-based surveys conducted during the winters of 1995/96, January 1997, and 1997/98

near the shore station at Granite Canyon, California. The proportions of calves to adults

observed from 1995 to 1998 (0.003 - 0.015) were similar to those recorded from 1984 to

1995 (0.001 - 0.009). The highest number of sightings occurred during the 1997/98

season with 61 calves reported. The proportion of calves visible from the air in 1996

(0.0308) was much higher than the proportion observed in 1988 (0.0024) but fell between

the proportions observed in 1993 and 1994 (0.0238 and 0.0440). The distribution of

cows with calves relative to shore was similar to earlier years where the majority of

sightings occurred inshore of the main migration corridor (1.4 - 2.8 km) during both

shore-based and aerial surveys. The median distance for shore-based sightings was 0.79

km compared to 1.34 km from the air during the 1995/96 season. Although calves

appeared to be closer to shore in 1995/96 when comparing shore-based observations from

earlier years (1.1 km from pooled data 1987-95); median distances during aerial surveys

were not different (1.3 km from pooled data 1988, 1993 and 1994). Shelden et al. (in

press) noted that it was rare that more than one independent observer at a time recognized

the presence of a calf. During the 1995/96 season, 12 calves were identified during 

paired-independent observations of which only 3 were also seen by the second observer. 

In January 1997, only 1 of 7 sightings were matched between observers, and during the

1997/98 season only 5 matches occurred among 40 sightings.
-68-

Agenda Section 2.2

2.3

SOUTHBOUND AND NORTHBOUND GRAY WHALE CALF SIGHTINGS 

OFF LOS ANGELES, 1984-99

Alisa Schulman-Janiger

American Cetacean Society, Los Angeles Chapter

2716 South Denison Avenue, San Pedro, CA 90731, USA

Schulman-Janiger, A. 1999b. Southbound and northbound gray whale calf sightings off Los Angeles,

1984-99. Unpubl. doc. submitted to the Workshop to Review the Status of the Eastern North

Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

For the past 16 seasons, trained volunteers have conducted the shore-based full-season

Gray Whale Census and Behavior Project, sponsored by the Los Angeles Chapter of the

American Cetacean Society (ACS/LA), at or near Point Vicente (near Los Angeles,

California). Gray whales and other cetaceans are counted from shore, 10-12 hours per

day, 7 days a week, for 5 to 6 months. Southbound counts have ranged from 301 to

1,301 per year, including 3 to 106 newborn calves. The percentage of southbound calves

sighted (number of calves/total southbound whales) during the first 7 years of our study

(1983/84 to 1989/90) ranged from 0.5% to 2.5%, averaging 1.7%. During the next three

seasons (1990/91 to 1992/93) these percentages increased to 3.0-3.9%, averaging 3.5%.

The calf percentages from 1993/94 to 1998/99 ranged from 2.0% to 8.6%, averaging

4.6%. However, the calf count in the 1998/99 migration (n = 15; 2.2%) was one of the

lowest in the past nine seasons. The highest calf count (n = 106; 8.6%) was in the

1997/98 season. These calf percentages are considerably higher than those published for

other censuses. As their numbers increase, more gray whales may delay departures from

northern feeding grounds (especially in seasons that include warmer arctic waters and late

ice formation); more females may give birth off southern California rather than in Mexican

calving lagoons, possibly subjecting calves to higher mortality rates. Gray whales with

newborns appear to favor a more protected coastal (rather than offshore) migratory

corridor, thus raising nearshore percentages of southbound calves. The relatively high

(and apparently increasing) percentage of southbound gray whale calves documented here

indicate that births off southern California are more common than previously thought. 

The northbound migration of cow/calf pairs peaks between 6 April and 27 April, generally

during the last half of April; this peak occurs 4-8 (averaging 6) weeks after the earlier

migration peak that primarily consists of whales with no calves. Northbound counts have

ranged from 793 to 3,412 per year, including 11 to 222 newborn calves. The percentage

of newborn calves sighted (number of calves/total number of northbound whales) during

the first nine seasons of our study (1983/84 to1991/92) ranged from 0.9% to 8.3%,

averaging 3.4%. During three seasons (1987/88, 1989/90, and 1990/91) the percentage of

northbound calves observed was actually lower than the percentage of southbound calves
-69-

observed earlier in those migrations; this occurred during a period of generally lower

whale counts. During the next six seasons (1992/93 to 1997/98) this percentage generally

increased: it ranged from 4.3% to13.8%, averaging 9.6%. Some of the highest

percentages, ranging from 9.4% to 13.8% (averaging 11.2%), have occurred in recent

years (1995/96 to1997/98). These were substantially higher than previously published

figures for California waters. The highest calf count (n = 222, 13.8%) occurred in the

1996/97 season and was more than double the count of any of the preceding nine seasons. 

However, the percentage of calves in the 1998/99 northbound migration was only 2.5%

(n = 34), well below percentages seen in recent years. Factors that may be contributing to

this increase in northbound calf percentages include: shore-based observers are detecting

a higher percentage of calves; there may be some shortening of gray whale calving

intervals; and, more calves may be surviving the first few months of life. These annual

counts, complementing those conducted from other areas, could help indicate whether

gray whale calf production is decreasing, stabilizing, or increasing.
-70-

Agenda Section 2.4

ANNUAL CALF PRODUCTION FOR THE CALIFORNIA STOCK OF GRAY

WHALES 1994-98 

[Preliminary Analysis]

Wayne L. Perryman, Meghan A. Donahue, Stephen B. Reilly, and Peter C. Perkins

Southwest Fisheries Science Center, NMFS, NOAA

P.O. Box 271, La Jolla, CA 92038, USA

Perryman, W.L., M.A. Donahue, S.B. Reilly, and P.C. Perkins. 1999b. Annual calf production for the

California stock of gray whales 1994-98 [Preliminary analysis]. Unpubl. doc. submitted to the

Workshop to Review the Status of the Eastern North Pacific Stock of Gray Whales, 16-17 March

1999, Seattle, WA.

We conducted shore-based sighting surveys to estimate the number of northbound

migrating gray whale calves passing Piedras Blancas, California, for four consecutive years

(1994-98). In addition, we conducted aerial surveys to determine offshore distribution of

the migration in 1994 and 1995, measured day/night migration rates with thermal sensors

in 1994-96, and maintained concurrent replicate watches near the peak of each migration

to estimate the proportion of the northbound cow-calf pairs missed by the census team. 

During good weather conditions, we counted 325, 194, 408, 501, and 440 calves during

1994-98 respectively. Correcting these counts for periods not on watch, calves passing

far offshore (1994 only), and for calves missed by the census team produced final

estimates of 1,000 calves (SE = 88.85) for 1994; 601 calves (SE = 69.56) for 1995; 1,141

calves (SE = 72.23) for 1996; 1,439 calves (SE = 78.62) for 1997; and a preliminary

estimate of 1,316 calves (SE = 77.56) for 1998. Calf production indices (calf

estimate/total population estimate) are 4.5%, 2.6%, 5.1%, 6.5%, and 5.9% for the years

1994-98, respectively. 
-71-

Agenda Section 2.5

RESULTS OF PHOTOGRAMMETRIC WHALING FOR GRAY WHALES

ALONG THE CENTRAL AND SOUTHERN CALIFORNIA COAST BETWEEN

1994 AND 1998

Wayne L. Perryman and Morgan S. Lynn

Southwest Fisheries Science Center, NMFS, NOAA

P.O. Box 271

La Jolla, CA 92038, USA

Perryman, W.L., and M.S. Lynn. 1999. Results of photogrammetric whaling for gray whales along the

central and southern California coast between 1994 and 1998. Unpubl. doc. submitted to the

Workshop to Review the Status of the Eastern North Pacific Stock of Gray Whales, 16-17 March

1999, Seattle, WA.

More than 25 years after the last gray whale was taken along the California coast under a

special permit issued by the IWC to study the biology and ecology of this population, we

began an aerial photogrammetric sampling effort with the goal of revisiting some of the

results derived from the examination of specimens. Analysis of length, maximum width,

and fluke width data for southbound gray whales indicate that the migration is led by large

whales, many of them ?pregnant females,” and that juvenile whales are most common late

in the migration. Calves photographed around the California Channel Islands averaged

4.60 m in length. Based on the proportion of ?pregnant” and recent postpartum females,

we estimate 15 January to be the median birth date for eastern Pacific gray whales.

Northbound calves photographed in late May averaged 7.10 m in length which is

inconsistent with the accepted growth curve for young gray whales. We estimate length at

1 year to be 8.6 m and propose a new growth curve. There was a significant positive

linear relationship between the length of a cow and her associated northbound calf. 

Lengths of cows with calves were shorter on average than adult females examined by Rice

and Wolman (1971: 12.3 m versus 12.7 m), which may reflect gunner selection for large

whales, stretching of specimens during processing, or bias in the photographic sample. 

Based on the relationship between log length and log width, northbound whales were

significantly thinner than those photographed southbound. This difference was most

pronounced between ?pregnant females” and northbound cows with calves. Our results

indicate that relatively small changes in condition or fatness of gray whales are detectable

in measurements from photographs.
-72-

Agenda Section 3.1

OBSERVATIONS AND PREDICTIONS OF ARCTIC CLIMATIC CHANGE:

POTENTIAL EFFECTS ON MARINE MAMMALS

Cynthia T. Tynan 1 and Douglas P. DeMaster2

1

Joint Institute for the Study of the Atmosphere and Ocean

University of Washington

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

2National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Tynan, C.T., and D.P. DeMaster. 1997a. Observations and predictions of arctic climatic change: potential

effects on marine mammals. Arctic 50(4):308-322.

Recent analyses have revealed trends over the past 20-30 years of decreasing sea ice

extent in the Arctic Ocean coincident with warming trends. Such trends may be indicative

of the polar amplification of warming predicted for the next several decades in response to

increasing atmospheric CO2. We have summarized these predictions and nonuniform

patterns of arctic climate change in order to address their potential effects on marine

mammals. Since recent trends in sea ice extent are nonuniform, the direct and indirect

effects on marine mammals are expected to vary geographically. Changes in the extent

and concentration of sea ice may alter the seasonal distributions, geographic ranges,

patterns of migration, nutritional status, reproductive success, and ultimately the

abundance and stock structure of some species. Ice-associated seals, which rely on

suitable ice substrate for resting, pupping, and molting, may be especially vulnerable to

such changes. As recent decreases in ice coverage have been more extensive in the

Siberian Arctic (60EE-180EE) than in the Beaufort Sea and western sectors, we speculate

that marine mammal populations in the Siberian Arctic may be among the first to

experience climate-induced geographic shifts or altered reproductive capacity due to

persistent changes in ice extent. Alteration in the extent and productivity of ice-edge

systems may affect the density and distribution of important ice-associated prey of marine

mammals, such as arctic cod Boreogadus saida and sympagic (“with ice”) amphipods. 

Present climate models, however, are insufficient to predict regional ice dynamics, winds,

mesoscale features, and mechanisms of nutrient resupply, which must be known to predict

productivity and trophic response. Therefore, it is critical that mesoscale processoriented studies identify the biophysical coupling required to maintain suitable prey

availability and ice-associated habitat for marine mammals on regional arctic scales. Only
-73-

an integrated ecosystems approach can address the complexity of factors determining

productivity and cascading trophic dynamics in a warmer Arctic. This approach,

integrated with monitoring of key indicator species (e.g., bowhead whale, ringed seal, and

beluga), should be a high priority. 
-74-

Agenda Section 3.1

THE INFLUENCE OF OCEANOGRAPHIC PROCESSES ON PELAGICBENTHIC COUPLING IN POLAR REGIONS: A BENTHIC PERSPECTIVE

Jacqueline M. Grebmeier1 and James P. Barry2

1Graduate Program in Ecology

The University of Tennessee

Knoxville, TN 37996, USA

2Scripps Institution of Oceanography

University of California - San Diego

La Jolla, CA 92093, USA

Grebmeier, J.M., and J.P. Barry. 1991. The influence of oceanographic processes on pelagic-benthic

coupling in polar regions: a benthic perspective. J. Mar. Syst. 2:495-518.

Benthic community abundance and biomass in polar marine systems is directly influenced

by food supply from the overlying water column. Variability in hydrographic regimes, ice

coverage, light, water column temperature and pelagic food web structure limit the

amount of organic carbon reaching the benthos. Data from the high Arctic and Antarctic

indicate that a large percentage of surface-produced organic matter is consumed by both

macro- and micro-zooplankton as well as recycled in the water column via the microbial

loop. This results in food-limited regimes for the underlying benthos. The few exceptions

are nearshore continental shelf systems, such as in the Bering and Chukchi Seas in the

western Arctic and portions of the Canadian Archipelago and Barents Sea in the eastern

Arctic, where high benthic abundance and biomass occurs due to a tight coupling between

water column primary production and benthic secondary production. A major difference

between the Antarctic and Arctic is that the nearshore deep Antarctic is characterized by

relatively high benthic abundance and biomass despite low water column production,

suggesting that stability, low disturbance levels and cold temperatures enable benthic

organisms to grow larger than in the Arctic. Both physical and biological disturbance

levels are high in the marginal seas of the Arctic and may directly influence benthic

productivity. The relationship between primary production and sedimentation of organic

material to the benthos is nonlinear due to its dependence on the role of the pelagic food

web. Therefore, in this review we will only discuss the pelagic system with respect to how

it impacts the net food supply reaching the benthos. A major objective of this review

paper is to demonstrate the influence of oceanographic processes on pelagic-benthic

coupling in polar regions from a “bottom-up” perspective, using benthic studies from

various regions in both the Arctic and Antarctic. Similarities and differences in

oceanographic processes, benthic abundance and biomass, and benthic carbon cycling

within these polar marine systems are discussed and areas for further research identified.
-75-

Agenda Section 3.2

PRODUCTIVITY OF ARCTIC AMPHIPODS RELATIVE TO GRAY

 WHALE ENERGY REQUIREMENTS

Raymond C. Highsmith and Kenneth O. Coyle

Institute of Marine Science, School of Fisheries and Ocean Sciences

University of Alaska Fairbanks

Fairbanks, AK 99775-1080, USA

Highsmith, R.G., and K.M. Coyle. 1992. Productivity of arctic amphipods relative to gray whale energy

requirements. Mar. Ecol. Prog. Ser. 83:141-150.

Amphipod crustaceans dominate the benthic community in vast areas of the northern

Bering Sea; they are the major prey of the California gray whale Eschrichtius robustus. 

The protected whale population is growing steadily and may be approaching the carrying

capacity of the amphipod community, one of the most productive benthic communities in

the world. The abundance and biomass of the amphipod community decreased during the

3-year period 1986 to 1988, resulting in a 30% decline in production. High-latitude

amphipod populations are characterized by low fecundity and long generation times. 

Large, long-lived individuals are responsible for the majority of amphipod secondary

production. A substantial reduction in the density of large individuals in the population

will result in a significant, long-term decrease in production. 
-76-

Agenda Section 3.2

DISTRIBUTION AND CARRYING CAPACITY OF GRAY WHALE FOOD

RESOURCES IN THE NORTHERN BERING AND CHUKCHI SEAS

Sam W. Stoker

Beringian Resources, Inc.

4920 Anderson Road, Fairbanks, AK 99709, USA

Stoker, S.W. In press. Distribution and carrying capacity of gray whale food resources in the northern

Bering and Chukchi seas. J. Cetacean Res. Manage. Special Issue 2.

During their summer residency in the Bering and Chukchi Seas, gray whales rely on the

rich benthic amphipod populations of the region to renew fat resources needed to sustain

them during their winter migration to and from the breeding lagoons of Mexico. Surveys

of gray whale population distribution on these northern grounds indicate that

concentrations of feeding whales return annually to certain locations, and that these

locations coincide, in most cases, with high density and high productivity amphipod

communities.

The annual impact of gray whales feeding within these preferred areas is probably

considerable. Studies of one of the high-use areas, the central Chirikov Basin between St.

Lawrence Island and the Bering Strait, indicate that gray whales disturb at least 6% of the

benthos each summer and consume more than 10% of the yearly amphipod production. 

Whether or not this rate of consumption is within sustainable bounds is unclear since it is

impossible, at this time, to assess additional demands imposed upon amphipod populations

by other predators such as epibenthic invertebrates and demersal fishes. There are

indications, however, that this resource is being stressed and that the gray whale

population is expanding its summer range in search of alternative feeding grounds.
-77-

Agenda Section 4.1

CHEMICAL CONTAMINANTS IN GRAY WHALES (ESCHRICHTIUS

ROBUSTUS) FROM THEIR WESTERN BERING SEA ARCTIC FEEDING

GROUNDS AND THE CALIFORNIA AND WASHINGTON COASTS

Karen L. Tilbury1, John E. Stein1, Cheryl A. Krone1, Gina M. Ylitalo1, Robert L.

Brownell, Jr.2, Merrill Gosho3, A. Blokhin4, Jennie L. Bolton1, and Don W. Ernest1

1Environmental Conservation Division

Northwest Fisheries Science Center, NMFS, NOAA

2725 Montlake Blvd. E., Seattle, WA 98112-2097, USA 

2Southwest Fisheries Science Center, NMFS, NOAA

P.O. Box 271, La Jolla, CA 90271, USA

3National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700, Seattle, WA 98115-0070, USA

4Pacific Research Institute of Fisheries and Oceanography (TINRO)

Vladivostok, Russia

Tilbury, K.L., J.E. Stein, C.A. Krone, G.M. Ylitalo, R.L. Brownell, Jr., M. Gosho, A. Blokhin, J.L.

Bolton, and D.W. Ernest. 1999. Chemical contaminants in gray whales (Eschrichtius robustus)

from off their western Bering Sea arctic feeding grounds and the California and Washington

coasts. Unpubl. doc. submitted to the Workshop to Review the Status of the Eastern North Pacific

Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

The gray whale (Eschrichtius robustus) is a coastal migratory baleen whale (Mysticete)

with a benthic feeding strategy and a long period of fasting during its southbound

migration and residence in the breeding grounds. The prolonged fasting may alter the

disposition of toxic chemicals within the animal. Additionally, gray whales have been

observed feeding in coastal waters, which may present a risk of exposure to toxic

chemicals in some regions. We measured the concentrations of organochlorines (OCs)

and trace elements in tissues and stomach contents collected from juvenile gray whales

that were taken off their Arctic feeding grounds in the western Bering Sea during a

Russian subsistence harvest. Blubber biopsy samples that were taken from gray whales off

the California and Washington coasts were also analyzed for OCs; previously we

measured these contaminants in tissues and stomach contents of gray whales that stranded

along the U.S. west coast and Alaska. There were no differences in the concentrations

(based on wet weight of tissue) of contaminants between female and male subsistence

animals. The lipid content [48 (5)%] of blubber for animals from the Arctic feeding

grounds was higher than that in the biopsy samples [9.4 (0.8)%] from free-ranging,

apparently healthy whales. Concentrations on a lipid basis of the sum of polychlorinated
-78-

biphenyls (3PCBs) in the juvenile stranded whales and the juvenile subsistence whales

were significantly different [19,000 (14,000) and 680 (67) ng/g lipid, respectively]. The

mean concentration of the 3PCBs for the biopsy samples was 2,000 (280) ng/g lipid

weight. We hypothesize that the higher concentration of 3PCBs in the stranded animals

may be due to the retention of OCs in blubber during fasting rather than to increased

exposure to these contaminants. The concentrations of certain trace elements (e.g.,

cadmium) is some tissues, such as kidney, were also elevated in the stranded animals. 

Moreover, aluminum in stomach contents and tissues of the subsistence whales was high

compared to other marine mammal species, which is consistent with the ingestion of

sediment during feeding.
-79-

Agenda Section 4.2

4.3

POTENTIAL IMPACT OF OFFSHORE HUMAN ACTIVITIES

ON GRAY WHALES

Sue E. Moore1 and Janet T. Clarke

SAIC, Maritime Services Division

3990 Old Town Avenue, Suite 105A

San Diego, CA 92110-2931, USA

Moore, S.E., and J.T. Clarke. In press. Potential impact of offshore human activities on gray whales.

J. Cetacean Res. Manage. Special Issue 2.

Gray whale (Eschrichtius robustus) reactions to offshore human activities have been

relatively well studied compared to those of other mysticetes. Studies of short-term

behavioural responses to underwater noise associated with aircraft, ships and seismic

explorations indicate a 0.5 probability that whales will respond to continuous broadband

noise when sound levels exceed ca. 120dB2 and to intermittent noise when levels exceed

ca. 170dB, usually by changing their swimming course to avoid the source. Gray whales

‘startled’ at the sudden onset of noise during playback studies, but demonstrated a

flexibility in swimming and calling behaviour that may allow them to circumvent increased

noise levels. Whales may be ‘harassed’ by noise from large commercial vessels, especially

in shipping lanes or near busy ports. Gray whales sometimes change course and alter their

swimming speed and respiratory patterns when followed by whalewatching boats. 

Conversely, some whales swim toward small skiffs deployed from whalewatching boats in

breeding lagoons, seemingly attracted by the noise of idling outboard engines. Reported

gray whale reactions to aircraft are varied and seem related to ongoing whale behaviour

and aircraft altitude. Whale response to research involving tagging and biopsy sampling

appears to be short term. Gray whales were seen swimming through surface oil from the

Exxon Valdez oil spill along the Alaskan coast and showed only partial avoidance to

natural oil seeps off the California coast. Laboratory tests suggest that gray whale baleen,

and possibly skin, may be resistant to damage by oil, but spilled oil or oil dispersant in a

primary feeding area could negatively affect gray whales by contaminating benthic prey. 

Gray whales are sometimes injured or killed in collisions with vessels or entanglement in

fishing gear. Concern about the cumulative long-term impact of offshore human activities

is particularly acute in the Southern California Bight, where many activities are often

concurrent.

1Current address: National Marine Mammal Laboratory, Alaska Fisheries Science Center,

NMFS, NOAA, 7600 Sand Point Way NE, Bin C15700, Seattle, WA 98115-0070, USA.

2

dB re 1 FPa.
-80-

Agenda Section 4.3

BIO-ACOUSTICS OF THE GRAY WHALE (ESCHRICHTIUS ROBUSTUS)

Marilyn E. Dahlheim1

The University of British Columbia

Canada

Dahlheim, M.E. 1988. Bio-acoustics of the gray whale (Eschrichtius robustus). Ph.D. Thesis, University

of British Columbia. xiii+266 p.+appendices.

Gray whales (Eschrichtius robustus), while engaged in underwater signalling, circumvent

noise in the acoustical channel by the structure and timing of their calls. Data yielding this

conclusion were collected during an acoustical study on gray whales and their habitats

(1981-84). Sonographic analyses of tape recordings were used to quantify the acoustical

repertoire, the ambient noise characteristics of the area, and the relationship between the

animals’ calls and the environment. The acoustical responses of whales to artificially

increased levels of noise were documented during playback experimentation in Mexico. 

Nine sound parameters were inspected and compared between control and experimental

conditions: calling rates, call types, frequency range of signals (Hz), emphasized

frequencies (Hz), received levels of sounds (dB re 1 FPa), call duration (sec), percentage

of calls exhibiting frequency modulation, number of pulses per series, and repetition rates

of signals. The observed surface behavior of gray whales in response to noise (i.e., dive

durations, movements and abundance) was also investigated. Analyses yielded: a

description of gray whale call types; a characterization of the acoustical habitats occupied

by this species, including a list of sources contributing to the ambient noise and a profile of

the propagation characteristics of the study area; a determination of the relationship

between whale calls and their habitats; and the acoustical capabilities and strategies of

whales in response to noise. The plasticity observed in the overall behavior of this whale

is of adaptive significance when considering the dynamic nature of noise in the

environment. Typically, the multiple strategies employed by the whales when faced with

various noise situations enable them to minimize the detrimental effect that noise has on

their underwater signalling. Gray whale responses varied with the sound source and may

also differ relative to the geographical range and/or general behavior of the animal. It is

concluded that ambient noise (both natural and man-made) has a profound effect on the

behavior of this coastal species and that acoustical calling is modified to optimize signal

transmission and reception.

1Current address: National Marine Mammal Laboratory, Alaska Fisheries Science Center,

NMFS, NOAA, 7600 Sand Point Way NE, Seattle, WA 98115-0070.
-81-

Agenda Section 4.4

GRAY WHALE ENTANGLEMENTS

IN CALIFORNIA, OREGON/WASHINGTON, AND ALASKA, 1990-98

P. Scott Hill

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Hill, P.S. 1999a. Gray whale entanglements in California, Oregon/Washington, and Alaska, 1990-98. Unpubl. doc. submitted to the Workshop to

Review the Status of the Eastern North Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

Total number of entanglements reported during 1990-98 along the west coast of the United States (values in parentheses

indicate known mortalities and reports in which the status of the whale is unknown)

1998 1997 1996 1995 1994 1993 1992 1991 1990

CA 41 (2) 6

1

 (5) 5

2

 (4) 4 (1) 4

2

 (4) 1 (0) 4 (3) 4 (3) 5 (5)

OR/WA 0 0 0 2 (2) 0 0 0 1 (0) 2 (1)

AK 3 (3) 1 (1) 0 1 (0) 0 0 0 0 0 

Total 7 7 5 7 4 1 4 5 7

Data provided by J. Cordaro (SWR), B. Norberg (NWR), and M. Sternfeld (AKR). 

1May include 2 sightings of the same entangled whale.

2

Includes an unidentified whale that was most likely a gray whale.
-82-

Agenda Section 4.5

A REPORT TO THE MARINE MAMMAL COMMISSION ON

PROPOSED SALT PRODUCTION FACILITIES

AT SAN IGNACIO LAGOON BAJA CALIFORNIA

Bruce R. Mate

Oregon State University, Hatfield Marine Science Center

Newport, OR 97365, USA

Mate, B.R. 1995. A report to the Marine Mammal Commission on proposed salt production facilities at

San Ignacio Lagoon, Baja California. Unpubl. report to U.S. Marine Mammal Commission,

Washington, D.C. 13 p.

Exportadora de Sal, sometimes referred to as ESSA, has been a business partnership

between Mitsubishi, Japan (49%), and Mexico (51%) since 1954. It operates a salt

production facility at the town of Guerrero Negro, midway along the Pacific Coast of Baja

California. It is the world’s largest solar evaporative operation and produces 6.5 million

metric tons of salt per year from the adjacent Laguna Ojo de Liebre. ESSA is planning to

expand its operation to San Ignacio Lagoon.

Laguna Ojo de Liebre and San Ignacio Lagoon are both in the Vizcaíno Desert Biosphere

Reserve, Mexico’s largest refuge administered by Secretaria de Desarrollo Social

(SEDESOL), the Secretariat of Social Development. An Environmental Impact

Assessment was completed in July 1994 and was reviewed by SEDESOL. The application

was either denied or withdrawn in March 1995.

This report summarizes the activities of the current operation and the proposed activity

based on interviews with company officials in January 1995 and a review of the

Environmental Impact Assessment.
-83-

Agenda Section 4.5

4.6

CONSERVATION AND DEVELOPMENT IN THE GRAY WHALE LAGOONS

OF BAJA CALIFORNIA SUR, MEXICO

Serge Dedina and Emily Young

Department of Geography and Regional Development

University of Arizona

Harvill Building, Box #2

Tucson, AZ 85721, USA

Dedina, S., and E. Young. 1995a. Conservation and development in the gray whale lagoons of Baja

California Sur, Mexico. Final report to U.S. Marine Mammal Commission, Washington, D.C.

NTIS PB96-113154. iii+56 p.

In this report we identify ongoing and possible future development and related activities

that could have a negative impact on two of the three main calving/breeding habitats for

the eastern North Pacific gray whale (Eschrichtius robustus) population in Baja California

Sur, namely Laguna San Ignacio and Bahía Magdalena. We also identify steps that are

being or could be taken to assess and to prevent or minimize activities that may have

adverse effects. We provide: 1) a brief summary of the natural history, exploitation,

protection, and current status of the gray whale population in Mexico; 2) a description of

the physical and human geography of the study area; 3) a history of environmental

conservation efforts in the study area; 4) an overview of the environmental management

structure in the study area and the environmental impact review process in Mexico;

5) descriptions of past, existing, and planned development and commercial activities in the

study area; and 6) descriptions of impediments to effective assessment and control of

activities with potentially adverse impacts and possible means to strengthen current gray

whale conservation.

This study is based on field research undertaken in Laguna San Ignacio and Bahía

Magdalena. We also conducted background research and interviews in San Diego,

California, La Paz, Baja California Sur, and Mexico City. The research included: 1) openended and semi-structured interviews with local residents, government officials and others

with knowledge of the area and matters of interest or concern to this study; 2) participant

observation of local residents’ activities; 3) a review of archival sources on the history of

the study area and gray whale conservation; and 4) a review of newspaper coverage of

issues related to gray whale conservation in Baja California Sur. This enabled us to

compare actual use and management of gray whale habitats with: how government

officials think these areas are and should be used and managed; and how different user

groups in the study area view regulations of their activities for gray whale habitat

management.
-84-

Laguna San Ignacio is the only primary gray whale breeding/calving area in Mexico that

remains superficially unaltered. In contrast, portions of Bahía Magdalena have been

changed by industrial and mining activities, as well as part of the Vizcaíno Biosphere

Reserve. Bahía Magdalena remains unprotected.

Three federal agencies are responsible for on-site protection of gray whales and regulation

of human activities in Laguna San Ignacio and Bahía Magdalena. These are the National

Institute of Ecology (INE), the Federal Attorney General’s Office for Environmental

Protection (PROFEPA), and the Secretariat of Fisheries (Pesca).

The greatest potential threats to the whales and their habitat are from: 1) the proposed

development of a 52,150 ha salt production facility on the shore of Laguna San Ignacio;

2) a proposed tourist resort development at Bahía Magdalena; and 3) the growth of gray

whale tourism in the North Zone of Bahía Magdalena. Strict review and monitoring of

development and whale-tourism by INE, PROFEPA, and Pesca under existing

environmental impact assessment regulations, and the review of project plans and tourism

activities by non-governmental organizations, research institutions, and scientists familiar

with gray whale habitat, could help to minimize potentially adverse impacts.
-85-

Agenda Section 4.5

SAN IGNACIO SALTWORKS:

SALT AND WHALES IN BAJA CALIFORNIA

Secretaria de Medio Ambiente, Recursos Naturales y Pesca (SEMARNAP)

Periférico Sur 4209

Fracc. Jardines en la Montaña, 14210

Tialpan, D.F., México

SEMARNAP (Secretaria de Medio Ambiente, Recursos Naturales y Pesca). 1997. San Ignacio saltworks:

Salt and whales in Baja California. 25 p.

The desert-like central region of the Baja California peninsula has characteristics that are

unique in the world. One notable facet of its rich wildlife is that some of its coastal waters

are winter sanctuaries where the gray whale reproduces. A significant area of this region

was declared a Biosphere Reserve in 1988 (El Vizcaíno, the largest in the country: more

than two and a half million hectares). 

In 1994, a company (Exportadora de Sal, S.A. de C.V.) entered into negotiations with the

environmental authorities to considerably expand its salt extraction and marketing

activities within the Reserve’s buffer zone. In 1995, owing to insufficiencies in the

Statement of Environmental Impact (MIA, acronym in Spanish), the authorities denied the

corresponding permit. In view of the company’s wish to reopen negotiations for the

project, and in order to address the unusual complexity of the analysis, the authorities

established a Scientific Committee made up of seven distinguished specialists of different

nationalities. This Scientific Committee was entrusted with specifying the terms of

reference necessary for a new MIA (July 1996). Mexico’s environmental authorities also

pledged to submit to the consideration of the Committee any new MIA that might be

presented, and to respect its opinion in any decision taken. The establishment of such a

significant Scientific Committee and its public performance in assessing environmental

impact is without precedent in this country, and possibly in Latin America. 

To date, no proposal based on the rigorous terms of reference agreed upon has yet been

received.

Irrespective of the economic importance of the project, the Government of Mexico will

not authorize any proposal that runs counter to current regulations and that could

jeopardize conservation of the region’s natural resources, and in particular, its biological

richness, which is the heritage of all Mexicans.
-86-

Agenda Section 4.71

DESCRIPCIÓN Y DESARROLLO DE LAS ACTIVIDADES TURÍSTICAS DE

OBSERVACIÓN DE BALLENA GRIS EN LAS LAGUNAS DE LA RESERVA DE

LA BIOSFERA “EL VIZCAÍNO” Y BAHÍA MAGDALENA, BAJA CALIFORNIA

SUR, MÉXICO, TEMPORADAS 1996 Y 1997

José Angel Sánchez Pacheco1

Reserva de la Biosfera “El Vizcaíno”

Instituto Nacional de Ecología SEMARNAP

A.P. #65 Guerrero Negro, Baja California Sur, C.P. 23940 México

Sánchez Pacheco, J.A. 1997a. Descripción y desarrollo de las actividades turísticas de observación de

ballena gris en las lagunas de la reserva de la Biosfera “El Vizcaíno” y Bahía Magdalena, Baja

California Sur, México, temporadas 1996 y 1997. [Description and development of tourist gray

whale watching activities in the lagoons of the biosphere reserve “El Vizcaíno” and Magdalena

Bay, Baja California Sur, Mexico, during the 1996 and 1997 seasons.] Boletín Pesquero CRIP-La

Paz 7:8-18.

A description is given of the development and monitoring of gray whale watching in the

lagoons of the biosphere reserve “El Vizcaíno” and Magdalena Bay in 1996 and 1997. 

Described are the operations of the tourist industry in each lagoon, the observation time,

the number of vessels involved, and an analysis of the demand for services. The above is

discussed in light of the rules that regulate whale watching activities in Mexico. The 4

lagoons were visited by 23,971 tourists to whale watch in 1996 and 28,484 in 1997. This

activity was estimated to generate a total of $321,590 in 1996 and $453,300 in 1997 for

whale watching trips alone. An estimation of the economic activity generated included all

services and expenses incurred by tourists at their whale watching destination and while

traveling.

1Current address: A.P. #71, Guerrero Negro, Baja California Sur, C.P. 23940 México

E-mail: jasanpa@compuserve.com
-87-

Agenda Section 4.72

DETERMINACION DE LA CAPACIDAD DE CARGA EN TERMINOS 

DEL NÚMERO MÁXIMO SIMULTÁNEO DE EMBARCACIONES 

EN LAGUNA OJO DE LIEBRE Y LAGUNA SAN IGNACIO 

AREAS DE OBSERVACIÓN DE BALLENA GRIS 

EN BAJA CALIFORNIA SUR, MÉXICO

José Angel Sánchez Pacheco1

Reserva de la Biosfera “El Vizcaíno”

Instituto Nacional de Ecología SEMARNAP

A.P. #65 Guerrero Negro, Baja California Sur, C.P. 23940 México

Sánchez Pacheco, J.A. 1997b. Determinacion de la capacidad de carga en terminos del número máximo

simultáneo de embarcaciones en Laguna Ojo de Liebre y Laguna San Ignacio areas de

observación de ballena gris en Baja California Sur, México. [Determination of the carrying

capacity in terms of maximum simultaneous number of vessels in the Ojo de Liebre Lagoon and

San Ignacio Lagoon gray whale observation areas in Baja California Sur, Mexico.] Boletín

Pesquero CRIP-La Paz 7:19-25

The change in the direction of movement of whales is considered an indicator of

disturbance. A procedure was defined to estimate the Maximum Simultaneous Number

(NMS, acronym in Spanish) of vessels that can watch whales in an area without disturbing

more than 50% of them. In this procedure, vessels followed selected whales, while

observers recorded whale reactions and the distance between the vessel and disturbed

whales. The procedure was applied in Ojo de Liebre Lagoon and San Ignacio Lagoon

during 1995. The NMS was 6 vessels in each of two areas in Ojo de Liebre Lagoon and

13 vessels in San Ignacio Lagoon.

1Current address: A.P. #71, Guerrero Negro, Baja California Sur, C.P. 23940 México

E-mail: jasanpa@compuserve.com
-88-

Agenda Section 4.8

GRAY WHALE STRANDINGS

IN CALIFORNIA, OREGON/WASHINGTON, AND ALASKA, 1990-98

P. Scott Hill

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Hill, P.S. 1999b. Gray whale strandings in California, Oregon/Washington, and Alaska, 1990-98. Unpubl. doc. submitted to the Workshop to Review

the Status of the Eastern North Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

Total number of strandings (excluding dead stranded whales in which the cause of death was due to entanglement) reported

during 1990-98 along the west coast of the United States 

1998 1997 1996 1995 1994 1993 1992 1991 1990

CA 30 9 10 12 15 11 14 15 9

OR/WA 3 3 3 8 3 2 3 13 13

AK 1 0 0 1 4 141 131 141 271

Total 34 12 13 21 22 271 301 421 491

Data provided by J. Cordaro (SWR), B. Norberg (NWR), and M. Sternfeld (AKR). 

11990-93 data for Alaska include 26, 12, 12, and 13 whales, respectively, seen during aerial surveys. Thus, the 1990-93 data are

not comparable to the data collected during 1994-98.
-89-

Agenda Section 4.8

GRAY WHALES STRANDED IN MEXICO, 1975-99

Héctor Pérez-Cortés Moreno

Instituto Nacional de la Pesca, CRIP

Km 1 Carretera a Pichilingue

La Paz, B.C.S., 23020 México

Pérez-Cortés Moreno, H. 1999. Gray whales stranded in Mexico, 1975-99. Unpubl. doc. submitted to the Workshop to Review the Status of the

Eastern North Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

Location/year 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987

Baja California - - - - - - - - - - - 1 -

Guerrero Negro Lagoon - - - - - 8 4 2 - * * * *

Outer Beach (Vizcaíno Bay) 4 - - - - 23 10 21 3 * * * *

Ojo de Liebre Lagoon 16 - - - 4 16 - 12 13 10 7 6 11

San Ignacio Lagoon - - 4 7 5 6 6 4 10 5 - - -

Outer Beach (San Ignacio area) - - - - - - - - - - - - -

Bahía Magdalena - 1 - 1 - - - 6 - 1 - - -

Outer Beach (Magdalena area) - - - - - - - - - - - - -

Gulf of California - - - - - - - 1 1 - 1 1 1

Total 20 1 4 8 9 53 20 46 27 16 8 8 12
-90-

Gray whales stranded in Mexico, 1975-99 (continued).

Location/year 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 Total

Baja California - - - - - - 1 - - - - - 2

Guerrero Negro Lagoon * * * * * * * * - - 1 3 18

Outer Beach (Vizcaíno Bay) * * * * * * * * - - 1 28 90

Ojo de Liebre Lagoon 12 21 16 45 22 8 5 13 - - 1 40 278

San Ignacio Lagoon - 3 - - - - - - 3 7 3 5 68

Outer Beach (San Ignacio area) - - - - - - - - - - - 5 5

Bahía Magdalena - - - - 1 - - - - 1 1 20 32

Outer Beach (Magdalena area) - - - - - - - - - 0 0 11 11

Gulf of California 1 6 - - - - - - - - - 2 14

Total 13 30 16 45 23 8 6 13 3 8 7 114 518

Data are as available from 1975 to 16 June 1999. Dashes indicate no data are available. Asterisks indicate that data from

Guerrero Negro Lagoon and Vizcaíno Bay are summarized with the data for Ojo de Liebre Lagoon for the respective years.

Data Sources:

Heyning and Dahlheim (in press).

Sánchez Pacheco (1998).

Urbán et al. (1998a).

Unpublished data, Instituto Nacional de la Pesca, CRIP.
-91-

Agenda Section 4.8

GRAY WHALE MORTALITY AT OJO DE LIEBRE AND GUERRERO NEGRO

LAGOONS, BAJA CALIFORNIA SUR, MEXICO: 1984-1995

José Angel Sánchez Pacheco1

Reserva de la Biosfera “El Vizcaíno”

Instituto Nacional de Ecología SEMARNAP

A.P. #65 Guerrero Negro, Baja California Sur, C.P. 23940 México

Sánchez Pacheco, J.A. 1998. Gray whale mortality at Ojo de Liebre and Guerrero Negro lagoons, Baja

California Sur, Mexico: 1984-1995. Mar. Mammal Sci. 14(1):149-155.

During a study of gray whale strandings at Ojo de Liebre and Guerrero Negro lagoons,

conducted from 1984 to 1995, a total of 191 whales was found. Length was determined

for 176 whales, sex was determined for 146, and time of death was estimated for 117. 

Common stranding locations within and adjacent to the lagoons were identified. Most

(77%) of the calf mortality occurred between 15 January and 15 February. Stranded

whales were divided into three size/age classes based on the frequency distributions of

their lengths: calves (3.4 to 6.5 m, 0 = 4.63), yearlings (6.6 to 9.5 m, 0 = 8.13), and

2 years and older (9.6 to 14.2 m, 0 = 11.94). During 1990-1992, an extraordinary number

of whales 2 years and older stranded in the study area, with a maximum of 37 in 1991. 

Differences in the average lengths between female and male neonates and yearlings were

not statistically different, but females were longer than males at two years and older. It

was possible to determine causes of death in only a few cases.

1Current address: A.P. #71, Guerrero Negro, Baja California Sur, C.P. 23940 México

E-mail: jasanpa@compuserve.com
-92-

Agenda Section 4.9

GRAY WHALE SHIP STRIKES

IN CALIFORNIA, OREGON/WASHINGTON, AND ALASKA, 1990-98

P. Scott Hill

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Hill, P.S. 1999c. Gray whale ship strikes in California, Oregon/Washington, and Alaska, 1990-98. Unpubl. doc. submitted to the Workshop to Review

the Status of the Eastern North Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

Total number of vessel strikes reported during 1990-98 along the west coast of the United States (values in parentheses

indicate known mortalities and reports in which the status of the whale is unknown)

1998 1997 1996 1995 1994 1993 1992 1991 1990

CA 3 (2) 0 0 3 (1) n/a n/a n/a n/a n/a

OR/WA 0 0 0 0 0 0 0 0 1

AK 0 1 (1) 0 0 0 0 0 0 0 

Total 3 1 0 3 - - - - -

Data provided by J. Cordaro (SWR), B. Norberg (NWR), and M. Sternfeld (AKR). 

n/a indicates that data are incomplete for that year.
-93-

Agenda Section 5.1

5.2

RECORDS OF HARVESTED GRAY WHALES

Jennifer Quan

Cascadia Research

2181⁄2 W 4th Ave, Olympia, WA 98501, USA

Quan, J. 1999. Records of harvested gray whales. Unpubl. doc. submitted to the Workshop to Review the

Status of the Eastern North Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

Level of aboriginal harvest: In 1997 the International Whaling Commission set an

aboriginal subsistence quota. A total of 620 gray whales, not to exceed 140 annually, may

be taken over the years 1998-2002. 

5.1) Russian take: Over the years 1998-2002 the Russian Federation has agreed to

take no more than 135 whales annually. From 1970 to 1998 an average of 139 gray

whales were taken annually (Table 1).

5.2) Alaskan take: Currently there are no allocations for a gray whale harvest by

Alaskan Natives and none have been in place since 1991. An incidental take of two

gray whales by Alaskan Natives occurred in 1995 (Table 1).
-94-

Table 1 (Continuation of Agenda Sections 5.1 and 5.2). Numbers of Eastern North

Pacific gray whales harvested (including whales that were lost) between1970 and 1998. 

Parenthetic numbers in the USSR/Russia column indicate alternate counts from other

sources. 

Year USSR/Russia USA Totals

1970 146

1,2,3

5

4

151

1971 150

1,2,3

3

4

153

1972 181

1,2,3

1

4

182

1973 178

1

(173)

2,3

178

1974 181

1,2,3

3

4

184

1975 171

1,2,3

171

1976 165

1

(163)

2,3,5

165

1977 186

1,2,3

1

4

187

1978 182

1,2,3

2

4

184

1979 178

1,2,3

4

4

182

1980 179

1,2,3

3

4

182

1981 136

1

(135)

2,3,6

136

1982 165

1,2,3

4

6

169

1983 169

1

(168)

2,3

2

7

171

1984 169

1,2,3

169

1985 169

1,2,3

1

8

170

1986 169

1,2,3

2

9

171

1987 158

1

(154)

2,3

158

1988 150

1,2,3

1

10

151

1989 179

1,2,3

1

11

180

1990 162

1,2,3

162

1991 169

1,2,3

169

1992 0

12

(169)

2

0

1993 0

2,3,12

0

1994 44

2,3

(42)

13

44

1995 90

2,3

(85)

14

2

15

92

1996 43

2

(38)

3

43

1997 79

16

79

1998 122

17

122
-95-

1

Ivashin (in press): Table 2.

2Russian Federation (1997): Table 3; the number reported in 1992 (169) was later found

 to be inaccurate (see IWC 1995).

3Blokhin (in press d).

4Marquette and Braham (1982).

5

IWC (1979).

6

IWC (1984).

7

IWC (1985).

8

IWC (1987).

9

IWC (1988).

10IWC (1990).

11IWC (1991).

12IWC (1995).

13IWC (1996).

14IWC (1997a).

15IWC (1997b).

16IWC (1999b).

17Meghan Donahue/Robert Brownell, Jr., Southwest Fisheries Science Center, NMFS, 

 P.O. Box 271, La Jolla CA 92038-0271.
-96-

Agenda Section 5.3

MAKAH WHALING

Patrick Gearin

National Marine Mammal Laboratory

Alaska Fisheries Science Center, NMFS, NOAA

7600 Sand Point Way NE, Bin C15700

Seattle, WA 98115-0070, USA

Gearin, P. 1999. Makah whaling. Unpubl. doc. submitted to the Workshop to Review the Status of the

Eastern North Pacific Stock of Gray Whales, 16-17 March 1999, Seattle, WA.

 The Makah Indian Tribe received a five-year quota from the International Whaling

Commission (IWC) in 1997 to harvest 20 gray whales for ceremonial and subsistence

purposes. The Tribe may harvest up to five gray whales per year from 1998 through 2002

with no more than 33 strikes. The IWC approved a combined 5-year quota of 620 gray

whales for aboriginal subsistence whaling by U.S. and Russian aboriginals based on the

aboriginal needs statement from each country. The U.S. government requested the quota

on behalf of the Makah Tribe in acknowledgment of the Makah's explicit treaty right to 

whaling (Treaty of Neah Bay, 1855). The NMFS-Northwest Regional Office will monitor

the hunt and work with the tribe to ensure that the hunt is conducted within IWC

guidelines. In accordance with an agreement between NOAA and the Makah Tribe, the

Makah whalers will limit their hunting to the Pacific Ocean areas to the west of the

entrance of the Strait of Juan de Fuca. The Makah hunt has no commercial aspects; the 

meat will be used only for local consumption and will not be sold. The Makah Tribe will

use traditional methods of harvest including use of a cedar canoe and hand-thrown

harpoon. However, to ensure humaneness of the hunt, the tribe will use a .50-caliber rifle

to dispatch the whale. Makah whalers struck and killed one gray whale on 17 May 1999

(Gosho14).
RECENT TECHNICAL MEMORANDUMS

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AFSC102 BUCKLEY, T. W., G. E. TYLER, D. M. SMITH, and P. A. LIVINGSTON. 1999. Food habits of some

commercially important groundfish off the coasts of California, Oregon, Washington, and British

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101 MCELDERRY, H., W. A. KARP, J. TWOMEY, M. MERKLEIN, V. CORNISH, and M. SAUNDERS.

1999. Proceedings of the first biennial Canada/U.S. observer program workshop, 113 p. NTIS No.

PB99-146482. 

100 SEASE, J. L., and T. R. LOUGHLIN. 1999. Aerial and land-based surveys of Steller sea lions

(Eumetopias jubatus) in Alaska, June and July 1997 and 1998, 61 p. NTIS No. PB99-140618.

99 SEASE, J. L., J. M. STRICK, R. L. MERRICK, and J. P. LEWIS. 1999. Aerial and land-based

surveys of Steller sea lions (Eumetopias jubatus) in Alaska, June and July 1996, 43 p. NTIS No.

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98 LAUTH, R. R. 1999. The 1997 Pacific West Coast upper continental slope trawl survey of groundfish

resources off Washington, Oregon, and California: Estimates of distribution, abundance, and length

composition, 284 p. NTIS No. PB99-133043.

97 HILL, P. S., and D. P. DEMASTER. 1998. Alaska marine mammal stock assessments, 1998, 

166 p. NTIS No. PB99-130791.

96 WING, B. L., M. M. MASUDA, C. M. GUTHRIE III, and J. H. HELLE. 1998. Some size relationships

and genetic variability of Atlantic salmon (Salmo salar) escapees captured in Alaska fisheries, 1990-

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95 ORR, J. W., M. A. BROWN, and D. C. BAKER. 1998. Guide to rockfishes (Scorpaenidae) of the

genera Sebastes, Sebastolobus, and Adelosebastes of the northeast Pacific Ocean, 46 p. NTIS No.

PB99- 114217.

94 THROWER, F., R. MARTIN, and R. HEINTZ. 1998. Effect of seawater entry date on 24-hour plasma

sodium concentration and survival of juvenile spring chinook salmon (Oncorhynchus tshawytscha)

reared in marine net-pens, 18 p. NTIS No. PB98-173545.

93 MURPHY, J. M., N. E. MALONEY, and B. L. WING. 1998. Distribution and abundance of zooplankton

in the north Pacific Subarctic Frontal Zone and adjacent water masses, 31 p. NTIS No. PB98-159163.

92 FRITZ, L. W., and S. A. LOWE. 1998. Seasonal distributions of Atka mackerel (Pleurogrammus

monopterygius) in commercially-fished areas of the Aleutian Islands and Gulf of Alaska, 29 p. NTIS

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91 WING, B. L., and J. J. PELLA. 1998. Time series analyses of climatological records from Auke Bay,

Alaska, 90 p. NTIS No. PB98-149206.

90 PACUNSKI, R. E., P. A. LIVINGSTON, and B. S. MILLER. 1998. Food of flathead sole 

Hippoglossoides elassodon in the eastern Bering Sea, 27 p. NTIS No. PB98-148679. 

89 WILKINS, M. E., M. ZIMMERMANN, and K. L. WEINBERG. 1998. The 1995 Pacific west coast

bottom trawl survey of groundfish resources: Estimates of distribution, abundance, and length and age

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