Special Status Species
Gray whale
Photo: Alaska Fisheries Science Center.
Common name: Gray whale
Scientific name: Eschrichtius robustus
Stock: Eastern North Pacific
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Range Habitat Movements
Abundance Natural History Threats
Conservation Research Gaps Recommended Actions
References Resources

Listing Status
Endangered Species Act (?)
Status: Delisted 1994
Critical Habitat: Not designated
Recovery Plan: N/A (delisted)
Five Year Status Review: Completed in 19991

California Endangered Species Act (?)
Status: Not listed

Marine Mammal Protection Act (?)
Status: Non-strategic stock
Stock Assessment: Updated in 20052

The World Conservation Union (IUCN) (?)
Status: Least Concern

Convention on International Trade in Endangered Species (CITES) (?)
Appendix I

Geographic Range

The Eastern North Pacific stock is found in waters off the west coast of North America between winter calving grounds along the Pacific coast of Baja California and the southeastern Gulf of California, and summer feeding grounds in the Bering and Chukchi Seas between Alaska and Russia (Figure 1 & 2). A separate stock (the Western North Pacific stock) migrates between winter calving areas along the coast of China and summer feeding grounds in the Okhotsk Sea.3 The western stock is one of the most critically endangered populations of large whales with approximately 100 animals.3 Gray whales occurred formerly in the North Atlantic Ocean, but this population became extinct probably in the mid- to late-1600s.4


Gray whales seasonally migrates through the nearshore habitats of the MBNMS (Figure 2 & 3). This migration also takes this species through the other west coast National Marine Sanctuaries (e.g., Channel Islands, Gulf of the Farallones, Cordell Bank, and Olympic Coast).

Gray whale distribution map
Figure 1. Geographic distribution of the Eastern North Pacific stock of gray whales Eschrictius robustus.2
Download full-size figure (1.1 Mb PDF).

Migration route map
Figure 2. The migration route between feeding grounds in the Bering and Chukchi Seas and mating/calving grounds along the Pacific coast of Baja California, Mexico is indicated.
Download full-size figure (1.1 Mb PDF).

Gray whale sighting map
Figure 3. Sightings and group sizes (where available) for gray whales from Southwest Fisheries Science Center (SWFSC) aerial surveys conducted near San Nicolas Island (1992-1993) and San Clemente (1998-2003) and seven surveys of marine mammals compiled in the Computer Database Analysis System (CDAS) v2.1, 1975-1997 (reprinted from NCCOS 2005; see Figures 6.1.2 of that report for actual transects lines surveyed by SWFSC and Figure 6.1.5 for the survey effort of the surveys in the CDAS).42
Download full-size figure (1.1 Mb PDF).

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During migration, gray whales are observed in shallow coastal waters often within 1-3 nautical miles (1.8-5.6 km) of shore, though this distance from shore can increase in areas with a wide continental shelf (Figure 3).1,5 In the summer, gray whales are associated with shallow coastal and offshore-shoal areas usually less than 40 m deep in the Northern Bering and Chukchi Seas.6 Gray whales that summer in the waters around Vancouver Island, B.C., feed in shallow sand or mud bays, eel grass beds, kelp beds, in the open water column, and at the surface.7

In winter, females with calves and some breeding males use shallow lagoons and bays on the Baja California peninsula (Figure 4).8 Since the 1980s, shore-based observers near Los Angeles and Carmel, California have reported increased numbers of calf sightings during the southbound migration indicating that an increasing number of females are calving off the U.S. coast.9 It is suspected that some of these female-calf pairs remain in U.S. waters during the winter.10


The EN Pacific population migrates seasonally through the coastal and inner/outer shelf habitats of the MBNMS (Figure 3).11,12 Although most gray whales travel through this region as non-feeding migrants, some have been observed feeding opportunistically during the spring and early summer months in Monterey Bay as well as in San Francisco Bay, around South Farallon Island, and in the mouth of Drakes Bay and Tomales Bay.12,13

Lagoons map
Figure 4. Location of lagoons used by gray whales for mating/calving along the Pacific coast of Baja California, Mexico.
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Migration and Movements

Gray whales migrate between summer feeding grounds in the Bering, Chukchi, and western Beaufort Seas and winter breeding/calving areas off the west coast of Baja California (Figure 2). Important birthing areas include Laguna Ojo de Liebre, Laguna Guerrero Negro, Laguna San Ignacio, Bahia Ballenas, Santo Domingo Channel, Bahia Magdalena, and Bahia Almejas (Figure 4).8 Genetic studies of breeding populations indicate that adults exhibit some level of site fidelity to their natal lagoons and that the EN Pacific population may be sub-structured on the wintering grounds.14

During migration gray whales move steadily in one direction while breathing and diving in predictable patterns. A number of tagged whales have been tracked traveling approximately 5-6 km/hr during migration.15,16 This species is seen traveling alone, as mother and calf pairings, or in small groups often segregated by sex and age class. Currently a few hundred individuals end their northward migration early and spend the summer in "resident" feeding aggregations throughout a broad region extending from northern California to southwestern Alaska.17 The presence of resident gray whales is predictable in some locations (e.g., Vancouver Island) and highly variable in others (e.g., southern Puget Sound).7,17 Shelden and colleagues (2004) found that an increasing number of calves have been born north of Mexico in the last two decades, but it is unknown what proportion of these females-calf pairs may end their migration early and winter off the U.S. coast.9,10


Gray whales are seen migrating south through the MBNMS between mid-December and mid-February with abundance typically peaking in January.12 Females late in pregnancy tend to lead the migration followed, in order, by females that have recently ovulated, adult males, immature females and, lastly, immature males.18 Since 1980, an increased number of calves have been sighted along the central and southern California coast during the southbound migration.9 During the same time period a one-week shift in the timing of the southbound migration has also occurred resulting in the mean passage date for pregnant females near Carmel, CA (8-9 January); to coincide with estimates of the median calving date (10-13 January).5,18,19 Assuming the median calving date has not changed, one quarter to a half of pregnant females may be calving north of Carmel.9

The northward return migration primarily occurs from February to May with abundance typically peaking in March.12 Newly pregnant females begin the migration and are followed, in order, by adult males, immature females, immature males, and finally females with calves.18 Females with calves travel more slowly and the peak of their northbound migration typically occurs off Monterey during the last week of April.20

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Commercial whaling during the mid-1800s and early-1900s severely depleted the EN Pacific stock of gray whales to perhaps 1,000 to 2,000 whales.21 From 1967 to the late-1980s the population increased at an annual rate of approximately 3.3% (Figure 5).22 The population then remained relatively stable (within a range of about 18,000-23,000) through the mid-1990s.21 The estimated population size of 29,758 during the southbound migration in 1997/1998 was the highest ever observed.23 Then population estimates showed a marked decline; 19,448 in 2000/2001; and 18,178 for 2001/2002 (Figure 5).23

Calf counts at Piedras Blancas, a shore site in central California, showed a similar decline in 1999 and 2000. From 1994 to 1998 the estimated percentage of calves in the population fluctuated between 5.8% and 2.7%, but in 1999 and 2000 estimates dropped to 1.7% and 1.1%, respectively.24 Additionally, the number of stranded gray whales increased by approximately six times in these two years. Between Baja California and the Bering Sea a total of 283 and 368 strandings were reported in 1999 and 2000, respectively, compared to an annual average of 41 in previous years.25

One of the hypothesized reasons for the increased stranding rate is starvation due to a decline in benthic gammarid amphipods (the principal prey item) in the Bering and Chukchi Seas. This hypothesis is supported by the emaciated appearance of some of the migrating and stranded whales, the reduced calf production rates, and a higher proportion of the stranded animals being from adult and sub-adult age-classes than is normally observed.26 Decreased abundance of prey may have been caused by the increasing foraging pressure of the growing gray whale population, increasing water temperature over the previous decade, or a combination of these two factors.26,27 Alternatively, the decline in adult condition and calf production in 1999 and 2000 may have been related to sea ice covering the feeding grounds for a longer time period than usual during the early summer. Perryman and colleagues (2002) reported a negative correlation between length of time of ice cover in the northern Bering Sea and calf counts the following winter.24 When whales are forced to wait longer to access foraging areas, they may not be able to form as thick of fat reserves over the foraging season. In 2001, a year when sea ice cover retreated early in the season, strandings returned to "normal" levels (only 21 animals).23 Calf production rates appear to have returned to "normal" levels. Preliminary data from counts in 2003 estimate 1,500 calves, which is a calf production rate of over 7%.20 However, the capacity for gray whales to feed on a wide variety of prey along their migration route and the fact that some of the whales that stranded in 1999 and 2000 were in robust body condition suggests that the ultimate cause of the mortalities may have been multi-faceted and may never be fully explained.28


Most of EN Pacific stock transits through Sanctuary waters twice each year; an unknown number of animals remain in waters south of the MBNMS during the summer.

Gray whale abundance
Figure 5. Gray whale population abundance since 1967/68. The most recent survey occurred in 2001/02.21
Download full-size figure (1.1 Mb PDF).

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Natural History
Click here to view the natural history information of this species.


None of the threats listed below appear to be causing long-term declines in population size. However, these potential threats should be monitored because a dramatic increase in one or more of these threats could lead to population declines in the future.


Acoustic disturbance: Recent studies indicate that a variety of human generated noises, including sounds associated with offshore oil and gas development and vessel traffic, can cause changes in gray whale behavior.29 There is concern about the potential negative impacts of active-sonar, specifically low frequency (100-500 Hz) and mid-frequency (2.8-3.3 kHz) active sonar, used in military activities by the U.S. and other nations.30

Collisions with ships: From 1999 through 2003, five vessel strikes of gray whales were reported off the coasts of Washington, Oregon, and California.2 One of these animals appeared to have a non-fatal injury while the other four had fatal injuries. These numbers are likely to be underestimates of injury and mortality because not all whale strikes will be reported and some dead whales sink instead of washing ashore.

Disturbance from whale watching activity: The behavior of gray whales has been shown to change if whale watching boats approach too closely or cut in front of the path of the whale.29 Whale watching activities targeting gray whales are common in calving lagoons and at many locations (e.g., Monterey Bay) along the migration route. Mother-calf gray whale pairs appear to be particularly sensitive to disturbance by whale-watching boats.30

Declining prey resources: A decline in prey resouces could result from natural prey population fluctuations, effects of climate change on primary prey species, and/or competition for resources by an increasing whale population.

Entanglement in fishing gear: From 1999 through 2003, 22 gray whales were reported entangled in fishing gear off the coasts of Washington, Oregon, and California.2 Of these animals, 9 were killed and the remaining 13 either survived or their status was unknown. A minimum annual mortality rate incidental to commercial fishing of 14-15 gray whales is estimated based on stranding reports, logbook/self-reports, and observer data.2 Entanglement of adults and calves has been observed in Mexican waters during the winter breeding period.3

Habitat degradation (including chemical pollution, oil pollution, and coastal development): Any increase in offshore oil and gas development within the range of gray whales would increase both the potential of oil or chemical spills and the amount of shipping traffic through gray whale habitat. Currently, five energy consortiums have plans to build Liquefied Natural Gas terminals at different locations along the northern Baja California coast.3 Coastal development in and around lagoons in Mexico could degrade calving and breeding habitat. Gray whales abandoned Guerrero Negro Lagoon for many years in the 1960s due to high levels of shipping and dredging associated with an evaporative salt works project.31

Intentional Take: The International Whaling Commission (IWC) regulates subsistence harvesting of gray whales from the EN Pacific stock.


No threats are unique to the MBNMS

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Conservation and Research

In 1947 gray whales in the North Pacific were given complete protection under the International Convention for the Regulation of Whaling. The National Marine Fisheries Service (NMFS) is responsible for management of most marine mammal stocks in U.S. waters including the EN Pacific stock of gray whales. This stock was protected under the Endangered Species Act (ESA) from 1973 until 1994 when it was delisted. Although this stock is no longer protected under the ESA, it continues to be protected under the Marine Mammal Protection Act (MMPA), and subsistence take is managed under quotas set by the International Whaling Commission (IWC). Between 1999 and 2003, subsistence take shared between the Russian Chukotka people and the Makah Indian Tribe averaged 122 whales. Commercial take of gray whales is prohibited internationally by the IWC and the transportation of gray whale parts is regulated by CITES (Convention on International Trade in Endangered Species).

As required under the MMPA, NMFS completes Stock Assessment Reports for the EN Pacific stock of gray whales at least every 3 years. Current Stock Assessment Reports are available on the NOAA Office of Protected Resources website. The MMPA also requires the formation of Take Reduction Plans to reduce the incidental serious injury and mortality of marine mammals from commercial fishing operations. In 1997 NMFS implemented a Take Reduction Plan for Pacific Offshore Cetaceans to address incidental takes of cetaceans, including gray whales, in the California/Oregon swordfish drift gillnet fishery. The plan included skipper education workshops and required the use of pingers and minimum 36 feet extenders. Since implementation, overall cetacean entanglement rates in the California/Oregon swordfish drift gillnet fishery dropped considerably.2,32

NMFS conducted a review of the status of the EN Pacific stock at a workshop held by the National Marine Mammal Laboratory (NMML) in Seattle, Washington in 1999. This workshop concluded the 5-year status review of this stock following its removal from the List of Endangered and Threatened Wildlife and Plants. This stock's classification was determined to be “non-threatened” based on the growth rates and population estimates over the 5-year period after delisting (1994-1999) and the lack of evidence of any imminent threats to the stock. It was determined that monitoring should continue for an additional 5-year period (1999-2004) and that research should continue on human impacts to critical habitats.33

On-going research and monitoring programs by NMFS and other federal scientists include:

Abundance of Adults and Calves (Lead Scientist: Dave Rugh, National Marine Mammal Laboratory). Shore-based observers at Granite Canyon have conducted systematic counts of gray whales migrating south along the central California coast intermittently since 1967. The latest count was completed in 2001/2002. The next count will probably occur in 2005/2006. This project will be transitioning over to the NMFS Southwest Fisheries Science Center (SWFSC) over the next decade.20,34

Abundance of Calves (Lead Scientist: Wayne Perryman, NMFS-SWFSC). Shore-based observers at Piedras Blancas, California have conducted counts of gray whale calves during the northbound migration regularly since 1994. The latest count was completed in 2005, but the frequency of future counts is unknown.20

Condition Index (Lead Scientist: Wayne Perryman, NMFS-SWFSC). Photogrammetric studies provide data on number of pregnant whales, proportion of adults with calves, body lengths and other dimensions of whales. Dimension data can indicate animal health as a function of fat reserves.

Assessment of Northern Feeding Habitats (Lead Scientist: Sue Moore, NMFS-Alaska Fisheries Science Center (AFSC)). The objective of this project is to survey gray whale feeding habitats in the northern Bering Sea and south of Kodiak Island. The surveys are not funded, so they occur opportunistically.

Marine Mammal Health and Stranding Response Program Network (Southwest Regional Stranding Coordinator: Joe Cordaro, NMFS-SWFSC). The network consists of volunteer groups that respond to marine mammal strandings in different parts of the southwest region. Samples from stranded animals provide information on biological parameters, including age, length, reproductive condition, contaminant load, stock discreteness, types of parasites or diseases, and cause of death. In addition to collecting data from stranded animals, this program assesses health trends, correlates health with available data on physical, chemical, environmental, and biological parameters, and coordinates effective responses to unusual mortality events.


The two survey sites used to regularly monitor the size of the EN Pacific stock are located in the MBNMS; Granite Canyon is just south of the Monterey Bay and Piedras Blancas is near the southern border of the Sanctuary.

Beach COMBERS - Coastal Ocean Mammal and Bird Education and Research Surveys (Project Leader: Hannah Nevins, Moss Landing Marine Laboratories). In 1997 the MBNMS began a beach survey program using trained volunteers to survey beached marine birds and mammals monthly at selected sections of beaches throughout the Monterey Bay area. Currently, the program monitors 45 km of beaches in the MBNMS. The program is a collaborative project between MLML, MBNMS, and other state and research institutions, with the specific goal of using deposition of beach cast carcasses as an index of the health of the sanctuary. The Marine Mammal Health and Stranding Response Program Network is notified of all stranded or dead cetaceans so that data can be collected and the cause of the stranding event determined.


The California Department of Fish and Game (CDFG) is not required to have research and monitoring programs for gray whales because this species is not listed as threatened or endangered under the California Endangered Species Act. However, when one or more state-managed fisheries negatively impact a species protected under the MMPA, NMFS (the lead management agency) works with CDFG to address the problem. Though, this species is incidentally taken in the CA/OR thresher shark/swordfish drift gillnet fishery, the level of take (~2.5 animals per year) is less than 10% of the Potential Biological Removal level (58 animals) determined by NMFS.2 Because this level of take is allowed under the MMPA, current regulations do not have to be modified to decrease entanglement rates.


The International Whaling Commission (IWC) was set up under the International Convention for the Regulation of Whaling, which was signed in Washington D.C. on December 2, 1946. The purpose of the Convention is to provide for the conservation of whale stocks and the development of the whaling industry. The IWC has prohibited the taking of gray whales in the Pacific Ocean since 1947. Currently, the IWC has 57 member nations and all members have agreed to uphold the prohibition on take of gray whales. The IWC does allow aboriginal subsistence take of otherwise protected species. For the EN Pacific stock, a total catch of 620 whales is allowed for the years 2003-2006 with a maximum of 140 in any one year.

The "Witness for the Whales" DNA surveillance program has a website, hosted by the University of Auckland, that can be used to identify illegal products from protected species of cetaceans. The website contains DNA sequences from a comprehensive and representative range of cetaceans against which a researcher can compare a DNA sequence acquired from "unknown" whale meat or other body parts. This information can be used to identify individuals or countries that are taking protected species. Between 1993 and 1999, analysis of cetacean products purchased in commercial markets in Japan revealed that 10% came from protected species, including 7 samples from gray whales.35 These findings have raised concerns about the possibility of illegal take of this species (especially from the western North Pacific stock) or illegal importing/exporting of whale products from subsistence whaling.

In 1988, Mexico designated three coastal lagoons (San Ignacio, Ojo de Liebre, and Guerrero Negro) as the Whale Sanctuary of El Vizcaino. In 1988, these lagoons were also designated as the Vizcaino Biosphere Reserve, part of a United Nations system of internationally significant natural areas. In 1993, they were designated as a Natural World Heritage Site. In the 1990's, two large coastal developments were proposed near gray whale nursery habitat: a 2,000-ha tourist resort on Magdelena Bay and a large evaporation facility on Laguna San Ignacio. Development plans have been deferred or canceled for both these projects.3 However, a new mega-development project, called “Nautical Steps” has been proposed that would build a system of harbors, wharves, hotels, restaurants, and airports along 2,500 miles of coastline on the western and eastern shores of the Baja pennisula.3 This development would lead to increased levels of boat traffic, whale watching activity, vessel noise, and pollution.


CIMT - Center for Integrated Marine Technologies: Wind to Whales (Contact: Andrew DeVogelaere, MBNMS). The Monterey Bay - from Pt. Año Nuevo to Pt. Lobos and out to 122°05' west longitude - is the focal region of the CIMT Wind to Whales Program. This project, which began in 1997, is an interdisciplinary collaborative research project involving scientists and engineers from UCSC, NMFS, Monterey Bay Aquarium Research Institute, Moss Landing Marine Labs, MBNMS, and Naval Postgraduate School. CIMT uses data collected via remote sensing, moorings and ship-board surveys to investigate linkages between: coastal upwelling, nutrient delivery, spatial and temporal variability in phytoplankton, and the distribution and abundance of organisms at higher trophic levels including squid, fishes, seabirds, sea turtles, pinnipeds, and whales. Currently, CIMT records the location and abundance of gray whales observed during monthly ship-board surveys in the Monterey Bay.

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Research Gaps
  • Determine the genetic variability within the EN Pacific gray whale stock (including “resident” populations) and between this stock and the Western North Pacific stock.
  • Research needed in winter breeding grounds includes: determine the proportion of the population that utilizes the different wintering areas both in Baja California and off the U.S. coast (are gray whales wintering in the MBNMS?); photographic identification studies; radio telemetry studies to better understand migration paths, rates of travel, and yearly variation in timing of migration; genetic research to determine if there is population substructure among lagoons; and calf production counts.8
  • 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. Modeling the outcomes of oils spills of different intensities and at different locations is needed to better understand the risks to gray whale populations.
  • Evaluate the long-term effects of whale watching operations both in the breeding habitats and in the MBNMS.
  • Determine the impacts of various types of acoustic disturbance that occur in the MBNMS, including noise from ships, boats, aircraft, and research, military and industrial activities.36,37
  • Determine changes in preferred summer feeding areas in response to changes in sea ice concentrations.

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Recommended Actions
  • Support a continued international ban on commercial hunting. Support efforts to detect and prevent illegal whaling.
  • Support management efforts that protect or reduced degradation of essential feeding habitats in U.S. waters and breeding/calving habitat in foreign waters.
  • Support the continuation of existing observer programs for U.S. commercial fisheries that have the potential to take or injure gray whales. Support formation of observer programs for Mexican commercial fisheries.8
  • Develop an oil-spill response protocol to minimize the effects of oil spills on migrating gray whales. Determine the risks to gray whales relative to different locations and intensities of oil spills. Review, update and implement a vessel traffic management system in and around Sanctuary waters to ensure the safe transport of petroleum and other hazardous materials.
  • Monitor whale-watching activities around gray whales; ensure that effective protective measures (e.g., vessel approach regulations) are developed and enforced; provide education outreach to commercial and private vessels regarding viewing regulations and develop incentives to increase voluntary compliance rates.39,40
  • Reduce injury and mortality from entanglement in and ingestion of marine debris, particularly abandoned fishing gear. Efforts should include education outreach to fishing industry, abandoned gear recovery, and entanglement/stranding response teams.41
  • If certain acoustical disturbances are found to negatively impact gray whales, work to minimize those activities in the MBNMS.

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Cited References  
1. Rugh DJ, Muto MM, Moore SE, DeMaster DP (1999) Status review of the eastern north Pacific stock of gray whales. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-AFSC-103.
2. Angliss RP, Outlaw R (2005) Draft Alaska Marine Mammal Stock Assessments 2005. Alaska Fisheries Science Center, U.S. Department of Commerce.
3. Marine Mammal Commission (MMC) (2001) Annual Report to Congress 2000. Marine Mammal Commission, Bethesda, Maryland.
4. Rice DW (1998) Marine mammals of the world: systematics and distribution. Society for Marine Mammalogy Special Publication No. 4
5. Rugh DJ, Shelden KEW, Schulman-Janiger A (2001) Timing of the southbound migration of gray whales. Journal of Cetacean Research & Management 3:149-155
6. Moore SE, DeMaster DP (1997) Cetacean habitats in the Alaskan Arctic. Journal of Northwest Atlantic Fisheries Science 22:55-69
7. Darling JD, Keogh KE, Steeves TE (1998). Gray whale (Eschrichtius robustus) habitat utilization and prey species off Vancouver Island, B.C. Marine Mammal Science14(4): 692-720.
8. Urbán-Ramirez J, Rojas-Bracho L, Perez-Cortes H, Gomez-Gallardo A, Swartz SL, Ludwig S, Brownell RLJ (2003) A review of gray whales (Eschrichtius robustus) on their wintering grounds in Mexican waters. Journal of Cetacean Research & Management 5:281-295
9. Shelden KEW, Rugh DJ, Schulman-Janiger A (2004) Gray whale born north of Mexico: indicator of recovery or consequence of regime shift. Ecological Applications 14:1789-1805
10. Kim Shelden, NOAA, NMFS, National Marine Mammal Laboratory, Alaska Fisheries Science Center, personal communication
11. Swartz SL (1986) Gray whale migratory, social and breeding behavior. Report to the International Whaling Commission Special Issue 8:207-229
12. NOAA National Centers for Coastal Ocean Science (NCCOS) (2003) A Biogeographic Assessment of North/Central California: To Support the Joint Management Plan Review for Cordell Bank, Gulf of the Farallones, And Monterey Bay National Marine Sanctuaries; Phase I - Marine Fishes, Birds and Mammals. Prepared by NCCOS's Biogeography Team in Cooperation with the National Marine Sanctuary Program, Silver Spring, MD.
13. Benson SR, Croll DA, Marinovic BB, Chavez FP, Harvey JT (2002) Changes in the cetacean assemblage of a coastal upwelling ecosystem during El Nino 1997-98 and La Nina 1999. Progress in Oceanography 54:279-291.
14. Goerlitz DS, Urbán-Ramirez J, Rojas-Bracho L, Belson M, Schaeff CM (2003) Mitochondrial DNA variation among Eastern North Pacific gray whales (Eschrichtius robustus) on winter breeding grounds in Baja California. Canadian Journal of Zoology 81:1965-1972.
15. Mate BR, Urbán-Ramirez J (2003) A note on the route and speed of a gray whale on its northern migration from Mexico to central California, tracked by satellite-monitored radio tag. Journal of Cetacean Research & Management 5:155-157.
16. Swartz SL, Jones ML, Goodyear J, Withrow DE, Miller RV (1987) Radio-telemetric studies of gray whale migration along the California Coast: a preliminary comparison of day and night migration rates. Report to the International Whaling Commission 37:295-299
17. Calambokidis J, Darling J, Deecke V, Gearin P, Gosho M, Megill W, Tombach C, Goley D, Toropova C, Gisborne B (2002) Abundance, range and movements of a feeding aggregation of gray whales (Eschrichtius robustus) from California to southeastern Alaska in 1998. Journal of Cetacean Research and Management 4:267-276.
18. Rice DW, Wolman AA (1971) The life history and ecology of the gray whale (Eschrichtius robustus). American Society of Mammalogists Special Publication Number 3: viii–142.
19. Perryman WL, Lynn MS (2002) Evaluation of nutritive condition and reproductive status of migrating gray whales (Eschrichtius robustus) based on analysis of photogrammetric data. Journal of Cetacean Research & Management 4:155-164.
20. Wayne Perryman, NOAA, NMFS, Southwest Fisheries Science Center, personal communication
21. Marine Mammal Commission (MMC) (2003) Annual Report to Congress 2002. Marine Mammal Commission, Bethesda, Maryland.
22. Buckland ST, Breiwick JM (2002) Estimated trends in abundance of eastern Pacific gray whales from shore counts (1967/68 to 1995/96). Journal of Cetacean Research & Management 4:41-48.
23. Rugh DJ, Hobbs RC, Lerczak JA ,Breiwick JM (2005) Estimates of abundance of the Eastern North Pacific stock of gray whales 1997 to 2002. Journal of Cetacean Research & Management 7(1):1-12.
24. Perryman WL, Donahue MA, Perkins PC, Reilly SB (2002) Gray whale calf production 1994-2000: Are observed fluctuations related to changes in seasonal ice cover? Marine Mammal Science 18:121-144.
25. Gulland FMD, Peres-Cortes M. J, Urbán R. J, Rojas-Bracho L, Ylitalo G, Weir J, Norman SA, Muto MM, Rugh DJ, Kreuder C, Rowles T (2005) Eastern North Pacific Gray Whale (Eschrichtius robustus) unusual mortality event, 1999-2000. U.S. Dept. Commer., NOAA Tech. Memo. NMFS-AFSC-150.
26. Le Boeuf BJ, Pérez-Cortés MH, Urbán-Ramirez J, Mate BR, Ollervides UF (2000) High gray whale mortality and low recruitment in 1999: potential causes and implications. Journal of Cetacean Resource Management 2:85-99.
27. Moore SE, Grebmeier JM, Davies JR (2003) Gray whale distribution relative to forage habitat in the northern Bering Sea: Current conditions and retrospective summary. Canadian Journal of Zoology 81:734-742
28. Moore SE, Urbán-Ramirez J, Perryman WL, Gulland F, Perez-Cortes MH, Wade PR, Rojas-Bracho LR, Rowles T (2001) Are gray whales hitting 'K' hard? Marine Mammals Science 4:954-958
29. Moore SE, Clarke JT (2002) Potential impact of offshore human activities on gray whales (Eschrichtius robustus). Journal of Cetacean Research & Management 4:19-25.
30. National Research Council (2005) Marine Mammal Populations and Ocean Noise: Determining When Noise Causes Biologically Significant Effects. Committee on Characterizing Biologically Significant Marine Mammal Behavior. National Academies Press, Washington, DC. 142 pages.
31. Bryant PJ, Lafferty CM, Lafferty SK (1984) Reoccupation of Laguna Guerrero Negro, Baja California, Mexico, by gray whales. In: Jones ML (ed) The Gray Whale Eschrichtius robustus. p 375-386. Academic Press, Orlando, FL.
32. Barlow J, Cameron GA (2003) Field experiments show that acoustic pingers reduce marine mammal bycatch in the California drift gill net fishery. Marine Mammal Science 19:265-283.
33. National Marine Fisheries Service (NMFS) (October 6, 1999) Notice of Report Availability. Gray whale research and monitoring. Federal Register Vol. 64, No. 193:54275-54276.
34. Dave Rugh, NOAA, NMFS, National Marine Mammal Laboratory, Alaska Fisheries Science Center, personal communication
35. Baker CS, Lento GM, Cipriano F, Dalebout ML, Palumbi SR (2000) Scientific Whaling: Source of Illegal Products for Market? Science 290:1695-1696.
36. Addressed in part by JMPR Wildlife Disturbance Issues - Marine Mammal, Seabird and Turtle Disturbance Action Plan: Low Flying Aircraft Disturbance Strategy. Joint Management Plan Review (JMPR). Proposed Action Plans. Draft report. Monterey Bay National Marine Sanctuary.
37. Addressed in part by JMPR Wildlife Disturbance Issues - Marine Mammal, Seabird and Turtle Disturbance Action Plan: Acoustic Disturbance Strategy. Joint Management Plan Review (JMPR). Proposed Action Plans. Draft report. Monterey Bay National Marine Sanctuary.
38. Addressed in part by JMPR Wildlife Disturbance Issues - Marine Mammal, Seabird and Turtle Disturbance Action Plan: Commercial Harvest Related Disturbance Strategy. Joint Management Plan Review (JMPR). Proposed Action Plans. Draft report. Monterey Bay National Marine Sanctuary.
39. Addressed in part by JMPR Wildlife Disturbance Issues - Marine Mammal, Seabird and Turtle Disturbance Action Plan: Vessel Disturbance Strategy. Joint Management Plan Review (JMPR). Proposed Action Plans. Draft report. Monterey Bay National Marine Sanctuary.
40. Addressed in part by JMPR Wildlife Disturbance Issues - Marine Mammal, Seabird and Turtle Disturbance Action Plan: Enforcement Activity Disturbance Strategy. Joint Management Plan Review (JMPR). Proposed Action Plans. Draft report. Monterey Bay National Marine Sanctuary.
41. Addressed in part by JMPR Wildlife Disturbance Issues - Marine Mammal, Seabird and Turtle Disturbance Action Plan: Marine Debris Strategy. Joint Management Plan Review (JMPR). Proposed Action Plans. Draft report. Monterey Bay National Marine Sanctuary.
42. NOAA National Centers for Coastal Ocean Science (NCCOS) (2005) A Biogeographic Assessment of the Channel Islands National Marine Sanctuary: A Review of Boundary Expansion Concepts for NOAA's National Marine Sanctuary Program. Prepared by NCCOS's Biogeography Team in cooperation with the National Marine Sanctuary Program, Silver Spring, MD. NOAA Technical Memorandum NOS NCCOS 21. 215 pp.
43. NOAA Fisheries website

References and Resources
Click here for images, reports, and links to other websites for this species.

Acknowledgement of Reviewers

Thank you to Karin Forney, Robyn Angliss, Jeff Breiwick, and Wayne Perryman for reviewing this report and providing helpful comments and corrections.

Content Last Modified: 02/2006

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