Status Review of the Eastern North Pacific Stock of Gray Whales

0,87

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106

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4905

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National Oceanic and Atmospheric Administration

2001

rok

CONTENTS

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

3) 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

6.3) 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