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I ,I I GMrvrS:94:~~}1.

Monitoring Seabird Populations in Areas of Oil I

and 'IGas '. S If lJ)evelopment on the Alaskan Contmental he:

f I I i ~STIM~TIES OF MARINE BIRD

AND SEA OTTER ABUNDANCE.

(N LO~E~ COOK INLET~ ALASKA

DURING SUMMER 1993 AND WINTER 1994

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. Final

Report.

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i . I· . . ... ... Beverly A..Agler, StevenJ. Kendall, Pamela E. Seiser, and David B. Irons

U,S. Fish ahd Wildlife Service, Migratory Bird M~migement, . I 'I . _ I .

101'1 East Tudor Road, Anchorage, Alaska 99503

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IIIIIIIIEm••mIIDIID
[ Estimates of Marine Bird and Sea Otter Abundance

in Lower Cook Inlet, Alaska during Summer 1993 and Winter 1994

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Beverly At Agler, Steven J.Kendall, Pamela E. Seiser, and David B. Irons

U.S. Fish and Wildlife Service, Migratory Bird Management,

. 1011 East Tudor Road, Anchorage, Alaska 99503 , , '

Final Report

oes Study

MMS 94·0063

•

May 1995

.'

Submitted to:

Minerals Management Service

Environmental Studies Section

949 E. 36th Avenue

Anchorage, Alaska 99508

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The, opinions, findings, conclusions, or recommendations expressed in this report are

those of the authors and do not necessarily reflect the views of the Minerals

Management Service, nor does mention of trade names or commercial products

constitute endorsement or recommendation for use by the Federal Government.

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TABLE OF CONTENTS

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TABLE, OF CONTENTS

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L1S,\ OF TABLES: , . . . . . . . . . . . . . . . . . . . .. . . . . .. v

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LIST, OF FIGURES. " , , . vii

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L1S1 OF APPENDICES .. : , IX I • .

AC~NOWLEDGMENTS ,. X

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EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

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INTRODUCTION . I

OBJECTIVES . , .:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. 2

( , : .

MET/"lODS , . ' '. . . . . . . . . . . . .. 2

I Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2

t Survey Methodology . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. 3

I DeSign of Sl;l~mer Boat Survey . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. 4

I Shoreline Stratum '. . . . . . . . . . . . . . . . . .. 4 , • I·

Offshore Stratum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " 4

Design of 'Winter Surveys ,.................. 5

Winter Boat Survey , : " 5

: Shoreline Stratum :.................. 5

I .: Bay Stratum :................... 5

: Pelagic Stratum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6

; Surveys Comparing Large and Small Boats . . . . . . . . . . . . .. 6 I I :

Winter, Aerial Shor$line Survey 6

I Statistical Analysis 7

I Grouping of Data '.. 7

! Population Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7

I' Dens~ies of Marine Birds . . . . . . . . . . . . . : ; . . . . . . . . . . . . . . . . . 8 I Relat!~e A~u~da~ce of Marine Birds . . . . . .• . . . . . . . . . . . . . . . . .. 8

. I Species Dlstnbutlon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9

i Comparison with Prince William Sound . . . . . . . . . . . . . . . . . . . . .. 9

! . Improvement of the Survey 9

Survey Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10

I

RESULTS ... ',' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10

Summer Boat Survey 10 , :

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Marine Birds ,..

, Population Estimates of Marine Birds .

Densities of Marine Birds .

Relative Abundance of Marine Birds .

Species Distribution .

Sea Otters : .

Population Estimates of Sea Otters .

Densities of Sea Otters .

Species Distribution ; .

Winter Boat Survey .

Marine Birds .

Population Estimates of Marine Birds .

Densities of Marine Birds . . . . . . . . . . . . . . . . . . . . . . . . . . .

Relative Abundance of Marine Birds ; .

Species Distribution .

Surveys Comparing Large and Small Boat Methods .

Sea Otters .

Population Estimates of Sea Otters .

Densities of Sea Otters ...........................,

Species Distribution .

Winter Aerial Shoreline Survey .

Marine Birds ' .

Number of Birds Observed .

Densities of Marine Birds .

'. Correction Factors .

Sea Otters ...........................•..............

Comparison with Prince William Sound .

Improvement of the Survey , .

Survey Frequency '.' .

DISCUSSION .

Comparison between Summer 1993 and Winter 1994 Surveys . . . . . . . . . .

Comparison with Previous Surveys .

Winter Aerial Shoreline Survey " .

Surveys Comparing Large and Small Boat Methods ' .

Comparison with Prince William Sound .

Summer Boat Survey .

Wimer Boat Survey . . . . . . . . . . . . . . . • . . . . . . . . . . . . . .

Improvement of the Survey .

Survey Freql1ency , .

CONCLUSIONS .

LITERATURE CITED

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LIST OF TABLES

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Table 1. Area (km2

) of strata used on boat surveys of Lower Cook Inlet during

I 'summer 1993 and winter 1994 to estimate populiition abundance of

I

I 'manne . b'rd' I :S •. , ..•. , .. , .• , , ,"....• , •.... , .. , .. ' . , . ' . '32 , .. , ...

Tab'e 2, Species :groups used to estimate population size of marine birds

, : during summer 1993 and winter 1994 boat surveys of Lower Cook Inlet . " 33

Table 3. Lislo! re-stratifications examined to determine how future surveys be

I re-stratified'to improve precision of estimates in sLirveys of marine birds

,l ,and sea otters in Lower Cook Inlet. Alaska . , ..... , . , . , . , , , .... , . .. 38

Table 4. Population estimates (N ± 95% CI) for species groups of marine birds

I "observedduring small boat surveys of Lower Cook Inlet in summer 1993

: and a combined small boat and shipboard survey in eastern Lower Cook

: Inlet in winter 1994 .. ,., ... ,.:.".: .. , ... , , , , . , . , . , ..., , , .. '. 40

Tablie 5. Population estimates (N ± 95% CI). by stratum. for species groups of

I ~u~~~~~~~30~s~~~d. o~ ~. ~~~I~ ~~at ~~~~~ ~~ ~ow~~ ~oo~ .Inlet dUring,. 41

Table 6, Densities (birdslkm2

) of species groups of marine birds observed on a

I small boat s'urvey of Lower Cook Inlet during summer 1993 , , ..... ' . . .. 42

Table 7. Relative abundance (%) of marine birds observed on a small boat

, survey of Lower Cook Inlet during summer 1993 ' . , .. , . , : , , " 43

Tabl~ 8. Population estimates (N ± 95% Cil. by stratum. for species groups of

I marine birds observed on a combined small boat and shipboard survey

. I of eastem Lower Cook Inlet during winter 1994 .. , ... , .. , ... , . , . , . " 44

Tabl~ 9. Densities' (birds/km2

) of marine birds observed on a combined small

boat and shipboard survey of eastern Lower Cook Inlet during ":,,inter

11994 " .... , .. ,., ... , ..... "", ... " .... "." .. " .... ,

Table 10. Relatille; abundance (%). listed by stratum, of marine birds observed

! on a combined small boat and shipboard survey of eastern Lower Cook

I Inlet during winter 1994 , . , , ' , .. , .... , , , . , ' , ... , . ' . , . ' . , . ' ., '. 46

Tabl~ 11. Comparison of population estimates (N ± 95% CI) of marine birds·

: observed qul-ing shipboard surveys of the pelagic stratum of eastern

I Lower Cook ,Inlet during winte~ 1994 ., .... " ... , .. ", ... "" .. '. 47

Tabl~ 12. Percentage of times CV's of population estimates from short (2 nm)

! segments ',calculated during a Monte Carlo simulation were lower than

, CV'sfromdata collected along nine lines of varying lengths, . , .. , . ' . , " 48 . .

Table 13. Number:and density of marine birds and mammals counted during

I an aerial surVey of the shoreline of western Lower Cook Inlet during

: winter 1994 , , ' , , , . .. 49

TablJ 14. NUrnber;anddensity of marine birds and mamr)1als counted during I an aerial shoreline survey of Kachemak Bay. Alaska during wmter 1994

I and population estimates (N) from a winter small boat survey , ', 51

Table 15. Densities of marine birds from an aerial survey of the Kachemak Bay

i and westemshorelines of Lower Cook Inlet during winter 1994..... , , .. , 53

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Table 16. Correction factors (CF) incorporating detection errors in counts of

marine birds from aerial surveys in Lower Cook Inlet during winter 1994 ... 55

Table 17. Densities (birds/km2

) of species groups of marine birds observed on

a small boat survey of Prince William Sound during July 1993 '" 56

Table 18. Densities (birds/km2

) of species groups of marine birds observed on

a small boat survey of Prince William Sound during March 1994 .... .-... 57

Table 19. Relative abundance (%), listed by stratum, of marine birds observed

on a small boat survey of Prince William Sound during July 1993 . . .. . . .. 58

Table 20. Relative abundance (%), listed by stratum, of marine birds observed

on a small boat survey of Prince William Sound dUring March 1994 . . . .. 59

Table 21. Coefficients of variation (CV) for species and species groups from

re-stratification of the study area used for a small boat survey of Lower

Cook Inlet during June, 1993 60

Table 22. Rank of coefficients of variation (CV) for species and species groups

from re-stratification of the study area used for a small boat survey of

Lower Cook Inlet during June, 1993 '.' 62

Table 23. Coefficients of variation (CV) for species and species groups from

re-stratification of the study area used for a small boat survey of Lower

Cook Inlet during June, 1993 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 64

Table 24. Possible re-stratifications of the study area used for a small boat

survey of Lower Cook Inlet ranked by species and coefficient of variation

(CV) '.' 66

Table 25. Comparison of power (%) to detect trends in abundance of marine

birds for biannual surveys and for surveys occurring every three years.

We examined four levels of precision (CV) with an average annual rate

of change of 10% : 68

Table 26. Comparison of power (%) to detect trends in abundance of marine

birds for biannual surveys and for surveys occurring every three years.

We examined four levels of precision (CV) with an average annual rate

of change of 5% . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 68

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, LIST OF FIGURES

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Fig. '1. Study ar'e~ used for a small boat survey ofmarine birds and sea otters

I in Lower Cook Inlet, Alaska, during summer 1993 '. : ' , , 69

Fig. ,2. Study area used for a combined small boat and shipboard survey of

, marine bird~ and sea otter~in Lower Cook Inlet, Alaska, during winter

I 1994 ....:. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . , . 70

Fig. 3. Study area used for an aerial survey of marine birds and sea otters in '

I Lower Cook: Inlet, Alaska, during winter 1994' 71

Fig, 4. The major Currents and tide rips of Lower Cook Inlet that influence l marine bird ~istribution and abundance ,

Fig. 5. The 2-minute latitude by 4-minute longitude grid used to separate i.starting loca1ions. of transects for a small boat survey of Lower Cook

f Inlet, Alas~a', dUring summer 1993 , .. 73

Fig. 6. Location ,of, a 0.1 nm (200 m) shoreline buffer and a 3 nm (5.6 km)

i coastal buffer used in a survey of Lower Cook Inlet during summer 1993

Fig. 7., Randomly-chosen transects (2 nm in length) used in a small boat

, survey of Lo~er Cook Inlet, Alaska, during summer 1993 75

Fig. 8. Transects used in a boat survey of Lower Cook Inlet, Alaska, during

I winter 1994 '. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 76

Fig. 9. Location bt'eastem and westem strata used to investigate methods to

I improve the p~ecision of the population estimate from a survey of Lower'

I Cook Inlet dunng summer 1993 , 77

Fig. 10. Location of eastern and western strata used to investigate methods to

I improve the precision of the population estimate from a survey of Lower

I Cook Inlet during summer 1993 .. , . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 78

Fig. 11. Location of north, Kamishak Bay, Kachemak Bay, and pelagic strata l used to investigate methods to improve the precision of the population

, estimate frorfl a survey of Lower Cook Inlet during summer 1993 . . . . . . .. 79

Fig. 12. Location of a 2.7 nm (5 km) buffer around colonies with >500 birds'

f used to eXamine re~strat!fication of Lower Cook Inlet to improve precision

, of estimates of manne bird abundance , . . . . . . . . . . . . . . .. 80

Fig. 1'3. Locatiori of a 5.4 nm (10 km) buffer around colonies with >500 birds I used to examine re-stratification of Lower Cook Inlet to improve precision

I of estimates 'of marine bird abundance . . . . . . . . . . . . . . . . . . . . . . . . . .. 81

Fig. 1,4" Location of a 8.1 nm (15 km) buffer around colonies with >500 birds

I used to e~ine re-stratification of Lower Cook Inlet to improve the

precision of estimates of marine bird abundance . . . . . . . . . . . . . . . . . . .. 82

Fig. 15. Location of a 0.1 nm (200 m) shoreline stratum and a 5 nm (9.3 km)

! coastal stratum used to examine re-stratification of Lower Cook Inlet to

I improve precision of estimates of marine bird abundance in future

I surveys. . ..:.............................................. 83

Fig. 16'-'

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Summer distribution of marine birds .: :.................. 84 . Fig.V. Summer,di,stribution of tubenoses (shearwaters, fulmars, and storm- ,

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petrels) . . . . ., . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .. 85

Fig. 18. Summer distribution of northem fulmars 86

Fig. 19. Summer distribution of fork-tailed storm-petrels ,............. 87

Fig. 20. Summer distribution of cormorants 88

Fig. 21. Summer distribution of waterfowl 89

Fig. 22. Summer distribution of gulls . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 90

Fig. 23. Summer distribution of tems 11 •....•.......... ,. 91

Fig. 24. Summer distribution of alcids ,... 92

Fig. 25. Summer distribution of murres 93

Fig. 26. Summer distribution of Brachyramphus murrelets . . . . . . . . . . . . . .. . .. 94

Fig. 27. Summer distribution of tufted and homed puffins .. . . . . . . . . . . . . . . .. 95

Fig. 28. Summer distribution of pigeon guillemots 96

Fig. 29. Summer distribution of sea otters 97

Fig. 30. Winter distribution of marine birds. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 98

Fig. 31. Winter distribution of loons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 99

Fig. 32. Winter distribution of grebes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 100

Fig. 33. Winter distribution of cormorants '. . . . . . . . . . . . . . . . . . . . . .. 101

Fig. 34. Winter distribution of waterfowl ; '.' . . . . . . . . .. 102

Fig. 35. Winter diStribution of eiders 103

Fig. 36. Winter distribution of harlequin ducks 104

Fig. 37. Winter distribution of goldeneyes ;...... 105

Fig. 38. Winter distribution of oldsquaws 106

Fig. 39. Winter distribution of scoters 107

Fig. 40. Winter distribution of gulls 108

Fig. 41. Winter distribution of alcids . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. .. 109

Fig. 42. Winter distribution of murres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 110

Fig. 43. Winter distribution of Brachyramphus murrelets .. . . . . . . . . . . . . . . .. 111

Fig. 44. Winter distribution of pigeon guillemots . . . . . . . . . . . . . . . . . . . . . . .. 112

Fig. 45. Winter distribution of sea otters . . . . . . . . . . . . .. 113

Fig. 46. Power to detect trends in marine bird abundance when confidence

level is 0.10 and: (a) mean coefficient of variation is 0.2, or (b) mean

coefficient of variation is 0.3 . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . .. 114

Fig. 47. , Power to detect trends in marine bird abundance when confidence

level is 0.10 and: (a) mean coefficient of variation is 0.4, or (b) mean

coefficient of variation is 0.5 '. . . . . . . .. 115

Fig. 48. Prince William Sound study area 116

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LIST OF APPENDICES

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Appendix A. Estimated population abundance of marine 'birds (N + 95% CI) I _

from small boat surveys of Lower Cook Inlet, Alaska in summer 1993

, ,and a combined small boat and shipboard survey during winter 1994 . . .. 117

Appendix B. Estimated population abundance of marine mammals

(N + 95% Cil from boat surveys of Lower Cook Inlet, Alaska in summer

1993 and winter 1994 121

Appendix C. Opportunistic sightings of marine mammals observed during boat i surveys of Lower Cook Inlet, Alaska in summer 1993 and winter 1994 . .. 122

Appendix D. Counts of marine birds and mammals within the 0.2 nm (400 m)

, zone during:an aerial survey of the Kachemak Bay and western

shorelines of Lower Cook Inlet in winter 1994 '.' . . . . . .. 123

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ACKNOWLEDGMENTS

i ,This project would not have been possible without the help of the many

observers who participated in the study. We thank Marcus Bradley (summer and

winter), Joel Cooper (winter), Belinda Dragoo (winter), Peter Fremgen (summer),

Bernie Krausse (s~mmer), John Maniscalco (winter), Sarah McClellan (winter), Lynne

Neibaur (summer):, Jon Pohl (summer), Marc Romano (winter), Bill Stahl (summer). Ed

Vodsek (winter), and Ann Wildman (summer) for their patience and humor during the

surVeys. We give: special thanks to Bill Butler and Bill Larned for flying the winter

1994 shoreline aeHal survey. During the summer 1993 survey, Michael and Cameron

Yourkowski, Glenn Caldwell, and Kim Fine, crew of the FN Kittiwake II, and Anne

Wieland, George West, and Merlin Cordes provided excellent field support. During

our winter 1994 sJrvey, Michael Youi"kowski, Glenn Caldwell, and Elizabeth Suttle,

crew of the RIV V1{aters, provided much needed expertise with the extreme winter

weather we encountered. Dave Erikson kindly provided us with charts of the aerial

surVey conducted 'in 1976 (Erikson 1977). John Martin, Gary Montoya, and the staff

of the Alaska Maritime National Wildlife Refuge, Homer, Alaska provided a great deal

of assistance during both surveys. Steve Klosiewski, Brad Andres, Karen Laing, Kent

Wohl, and Linda qampbell, Nongame Migratory Bird Project, Migratory Bird

Management provi,ded advice and support. Steve Arthur and Scott Hatch, National

Biological Service,: and Joel HUbbard, Minerals Management Service, kindly reviewed

the ~eport. This s(udy was funded by the U.S. Department of the Interior, Minerals

Management Service through Intra-Agency Agreement 14407 with the National

BiolOgical Service \:ind Fish and Wildlife Service as part of the Alaska Environmental

Stuqies Program. i . I

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EXECUTIVE SWMMARY , .

, We conduc!ed surveys of marine birds and sea alters (Enhydra lutris) in Lower

Cook Inlet, Alaska during June 1993 (summer) and February-March 1994 (winter).

During summer Hj93, we used small boats to survey 411 transects randomly-placed

throughout the Inl~t and recorded 56 bird and 6 mammal species. We estimated the

,overall summer pqpulation of birds (± 95% CI) as 798,042 ± 195,555 individuals.

During summer 1~93, population estimates were 37,333 '± 13,586; 254,975 ± 168.684:

and!505,733 ± 97'i995 marine birds in the shoreline ~0.1 nautical mile (nm) of shore),

coastal (>0.1 nm and ~3 nm of shore), and pelagic (>3 nm from shore) strata,

respeCtively. Tota'i bird density within the Inlet was 57.9 marine birds/km2

• Densities

by stratum were 152.9 birds/km2 in the shoreline, 71.6 birds/km2 in' the coastal, and

50.7 birds/km2 ir;l the pelagic strata.

, Alcid (Family Alcidae, 38.1 %) was the most common species group during _

summer 1993, and the majority of these were murres (Uria spp., 21.2% of total). The

secqnd most common species group was tubenose (Order Procellariiformes, 35%),

consisting of sheatwaters and fulmars (Puffinus spp. and Fulmarus glae/alis, 20.7% of , '

total) and storm-petrels (Oeeanodroi'na spp., 14.3% of total).

: Marine bird~ were distributed throughout the Inlet during summer 1993,

although the highest estimates of birds were near breeding colonies. Large numbers

of p~lagic species,! such as shearwaters and murres, were found in the eastern half of' , , I

the Inlet from Kachemak Bay south. .

i 'During wint~r 1994, we limited our survey area to the eastern portion of Lower

Cook Inlet. We .o~served 43 bird and 4 marine mammal species. We estimated that

the wintering bird population was 122,946 + 25,804 birds. We divided the winter study

area into three str~ta: shoreline ~0.1 nm of shore), bay (>0.1 nm and east of 152°04'

W lo'ngitude), and ~elagic (between 152°04' Wand 152°28' W longitude). We

estimated , that 14,611I ......

+ 2,792; 75,310 - -+ 21,069; and 33,025 _+ 14,634 birds were in

the shoreline, coa*al, and pelagic strata, respectively. Total density in the study area

was '33.6 birds/kmi during winter 1994. We calculated densities of 214.2 birds/km2 in

the shoreline stratl.Jm, 61.7 birds/km2 in the coastal, and 13.9 birds/km2 in the pelagic

strata. . : ,

I Watertowl (~amily Anatidae, 46.0% of total) was the most common species

group dUring winter 1994 with a population estimate of 56,607 + 19,985 birds. Most of

these were scote~ (Me/aniffa spp., 23.9% of total). We estimated that 40,271 ±

12,810 alcids (32.8%) were in the Inlet dUring our winter survey. The alcid species

g~oup consisted ofImurres (20.7% of total), .Brac~yramphus murrelets (":larbled and

Klltlltz's murrelets, lB. marmoratus and breVirostns; 9.5% of total), and pigeon

gUill~mots (CepphUs columba, 2.4% of total).

': Marine bird~ were distributed in ·Iow numbers throughout the study area during

winter 1994. Most:birds were found in the protected bays and fjords along the

southern shore of Kachernak Bay.

During winter 1994, we also conducted an aerial shoreline survey of western I ,

Lower Cook Inlet and Kachemak Bay. Along the western shoreline, we counted a ,

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. total of 1,486 marine birds within a 0.1 nm zone, an area comparable to our small

boat surveys, and 4,807 marine birds within a 0.2 nm zone, an area similar to that

USE!d by previous surveys (Erikson 1977, Arneson 1980). Most birds in both zones on

the west side were waterfowl (83%, 0.1 nm zone; 93%, 0.2 nm zone). In Kachemak

Bay, we counted 7,092 marine birds within the 0.1 nm zone and 15,775 birds in the

0.2 nm zone. In Kachemak Bay, most birds were either waterfowl (51%, 0.1 nm zone:

41% 0.2 nm zone) or alcids (34%, 0.1 nm zone; 46%, 0.2 nm zone) in both zones.

We estimated that 5,914 ± 3,094 sea otters were in Lower Cook Inlet diJring

summer 1993. Of these, 520 ± 534; 2,855 ± 2,014; and 2539 ± 2,287 sea otters were

in the shoreline, coastal, and pelagic strata, respectively. During winter 1994, we

estimated that 1,104 ± 592 otters were present in the eastern portion of Lower Cook

InIE!t. Of these, 172 ± 107 otters were in the shoreline stratum, 933 ± 583 otters were

in the bay stratum, and no otters were recorded in the pelagic stratum.

We also sighted other marine mammals including harbor porpoise (Phocoena

phocoena, summer only), Dall's porpoise (Phocoenoides dalll), minke whale

(Bcl/aenoptera acutorostrata, summer only), Steller sea lion (Eumetopias jubatus), and

harbor seal (Phoca vitulina).

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.,. , INTRODUCTION

· Lower Cook "nlet is an important area for many marine and coastal' birds

(Erikson 1977: Am~son 1980. Piatt 1993). but no estimate of the abundance of these

speCies has been determined for 15 years. In 1976, a year-long survey of Kachemak

Bay and Lower Cobk Inlet was conducted in response to potential petroleum

development in th~ area (Trasky et al. 1977). Eleven different environmental studies

were undertaken, ircluding studies of coastal morphology (Hayes et al. 1977).

circulation (Burbank 1977). distribution of king crab (Paralithodes camtschatica,

Haynes 1977) and iShrimp (Panda/us spp. and Panda/opsis dispar. Crow 1977), and

distribution and abundance of marine birds (Erikson 1977). Data from additional . ' I

marine bird surveys conducted in 1977-78 were combined with data from Erikson

(1977) in a compre,henSive report on the coastal migratory bird habitat of Alaska

(Arneson 1980). 'Bpth Erikson (1977) and Arneson (1980) determined seasonal

densities and distribution of marine birds in Lower Cook Inlet and identified important

habitats for these s'pecies. Although they provided baseline data on the area. these

studies (Erikson 19:77, Arneson 1980) were not designed to provide population · , estimates. I . ! In July 1992, Piatt (1993) conducted a shipboard survey to determine the

abundance of mari~e birds within a 50 kni radius of ihe Barren Islands, located in the

mouth of Lower Cobk Inlet Piatt's (1993) study area was further south in the rich · " I . waters surroundinglthe Barren Islands, so data from Piatt (1993) were not comparable

with ihis study. !

Seabirds ~re, vulnerable to a variety of human-related sources of mo~ality, such

as entanglement ,in Ifishing gear (DeGange and Day 1991) and adverse effects from oil

development (King and Sanger 1979). Oil and gas extraction and shipment have

beeniconducted in knd around Lower Cook Inlet for over 30 years, raising concem

about possibleeffe¢ts on marine species. The Minerals Management Service Cook

. Inlet Planning Area lis expected to be leased in 1996 (J. Hubbard, Minerals

Management Service, pers. commun.). To assess potential effects from additional , leases. it is necessary to obtain baseline data of the area. Thus, the Minerals

Management SeNide, the National Biological Service, and the U.S. Fish and Wildlife'

.Service funded ast~dy to determine seasonal marine bird and sea otter distribution

and abundance within Lower Cook Inlet.

( In June (summer) 1993, the U.S. Fish and Wildlife Service. Migratory Bird

Management con'd~cted a shipboard survey of Lower Cook Inlet, and in FebruaryMarc~ (winter) 1994, we conducted a combined small boat and shipboard surVey of

the eastern portion of the Inlet and an aerial survey of the western and Kachemak Bay

shorelines. Datafr6m these surveys will provide baseline data useful for monitoring

changes in bird abundance over time.

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OBJECTIVES

The overall purpose. of this study was to obtain baseline data on'the abundance

ancl distribution of marine bird and sea otter populations in Lower Cook Inlet during

summer and winter. Our primary objectives were to:

(1) develop population estimates, with 95% confidence intervals, of marine birds

and sea otters in Lower Cook Inlet during summer 1993 and winter 1994:

(2) examine marine bird and sea otter distributions within Lower Cook Inlet and

map these in a geographical information system; and,

(3) determine the relative abundance and densities of marine bird species

groups within the Inlet during summer 1993 and winter 1994 and

compare these data with data.from previous surveys of Lower Cook Inlet

(Erikson 1977, Ameson 1980) and Prince William Sound (Klosiewski and

Laing 1994, Agler et al. 1994a,d).

METHODS

Study Area

Lower Cook Inlet is a large embayment off the northwestem edge of the Gulf of

Alaska (Fig. 1). Our summer 1993 study area included all water within Lower Cook

Inlet and land within 0.07 nm (100 m) of shore. The southem boundary of the study

area was defined by a line from Cape Douglas on the Alaska Peninsula to Point Adam

on the Kenai Peninsula. The northem boundary was a line from Harriet Point on the

Alaska Peninsula to the'southwestem end of Kalgin Island then extending to Cape

Kasilof on the Kenai Peninsula (Fig. 1). The study area for the winter 1994 boat

survey (Fig. 2) included eastem Lower Cook Inlet from Ninilchik south (60°02' N

latitude) to approximately 20 miles north of the Barren Islands (59°04' N latitude). The

western boundary of the study area was the 152°28' W longitude line. During

February 1994, we also conducted an aerial survey of the shoreline of the western

sidEl of Lower Cook Inlet and Kachemak Bay. The aerial survey of the western

shoreline extended from Cape Douglas north to and including Tuxedni Bay, and

Kac:hemak Bay was surveyed from Bluff Point to Seldovia Point (Fig. 3).

Lower Cook Inlet is a physically diverse area, containing a wide variety of avian

habitats. The southeastem portion of the Inlet and the southem shore of Kachemak

Ba~' are made up of sheltered rocky bays and deep fjords. These waters are

generally ice-free in winter and provide important year-round habitat for marine birds·

(Erikson 1977, Ameson 1980). The'north side of Kachemak Bay and the coastline

alol'g the northeastem side of the Inlet consists mostly of sand beaches and shallow

mudflats with steep cliffs. Two major rivers, the Kenai and Kasilof, enter Lower Cook

Inlet south of the town of Kenai,adding to' the turbidity of the 'upper Inlet and lowering

salinities in this area (Burbank 1977). Several relatively shallow bays, with extensive

tida.! flats, are located on the westem side of the Inlet. For example, Kamishak Bay, in

the southwestem portion of the inlet, has extensive tidal flats and coastal floodplains.

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Lower Coo~ Inlet is surrounded by'large mouritains, the Aleutian Range on the

west and the Kenai Mountains on the east. This funnels winds Lip arid down the Inlet. , . I

predominantly southwest in spring and summer, and northeast in fall and winter

(Hayes et al. 1977". Many of the bays on the west side, Kaniishak Bay in particular,

frequently havel04alized, strong westerly winds due to air masses from Bristol Bay

moving through ,the mountain passes. The Kenai Mountains block moist air from the

Gulf of Alaska, res'ulting in a relatively low annual precipitation rate of 14-22 inches

along the northea~tern side of Lower Cook Inlet (Hayes et al. 1977). Precipitation is

higher on the northwestern side of the Inlet (Iniskin Bay, mean =73.2 in) due to

funneling of moist southerly winds into areas such as Kamishak Bay (Wagner et al.

1969). In winter" ite floes from Upper Cook Inlet are frequently found as far south as

Ninilchik, and the ~hallow bays off of Kamishak Bay may freeze over. Strong northerly

winds during the f~lI, winter, and spring concentrate sea ice in the western and

southwestern portions of the Inlet. '. '

Marine wat~rs within Lower Cook Inlet range from high salinity,' low turbidity

waters in the soutHeastern portion of the Inlet, caused by an influx of water from the

Alaska Coastal Cu~rent (Fig. 4), to relatively low salinity, turbid waters in the northern

and western portiohs of the study area (Erikson 1977). Waters within Cook Inlet are

also subject to a la'rgetidal range <±8 m, Hayes 1977) that generates strong currents.

Curr~nt velocities ~f 3.5 m/sec are common, and during spring tides, velocities may

exceed 7 m/sec (Hprrer 1967). The turbulence created by these swift tidal currents

causes Lower Coo~ Inlet to be fairly well-mixed with little ,stratification. Stratification

may 'develop seasonally due to high river discharge during the warmer months. The

tidal currents and ffesh water influx create a counterclockwise circulation pattern within I ' 1

Lower Cook Inlet (Fig. 4). ' I I ,

Survey Methodology .

, Survey methodology' was similar to other surveys conducted in Prince William

Soun,d (Irons et al. !1988a,b; Agler et al. 1994a,d; Klosiewski and Laing 1994) and

Southeast Alaska (J\gler et al. 1995) allowing comparison among coastal areas within

the Gulf of Alaska ecosystem. ' . r .' .

: Two obseN~rs surveyed a sampling window 0.07 nm (100 m) on either side,

aheaa of, and abolie the vessel (Klosiewski and Laing 1994). Observers estimated

the distance after p:racticing with objects at a known distarice. In winter 1994, we .

installed I radars on, each I boat, and we used these to maintain a distance of 0.07 rim

(100 m) from shore;. When surveying shoreline transects" observers also recorded

sightings on land, within 0.07 nm (100 m) of shore. Observers sampled continuously

and usedbinoeurars to aid in species identification. All birds within the survey window

were counted, and behavior (ie.- flying, sitting, or following) was recorded for each

sighting. Prior to b~inning each transect; observers recorded environmental data,

incluc:ling weather cpnditions, wind speed and direction, water and air temperature,

am04nt of ice, arld ~idal cycle. .

We surveyed during all phases of the tidal cycle. This may affect the species

and riumbers ob~eted but was unavoidable due to the logistics of covering such a

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laq~e area.' Many of the bays and shoreline areas in Lower Cook Inlet were shallow.

and mudflats extended far offshore during low tide. We usually surveyed transects in

these areas at high tide. If a mudflat was exposed, the'edge was considered the

shore, and transects were run from pre-determined latitudes and longitudes along this

edge.

During the summer survey (Agler et al. 1994b), most transects were surveyed

when wave height was ~1 ft, and we did not sample when wave height was >2 ft.

During the winter survey, we encountered extreme weather conditions (Agler et al.

19!14c). We surveyed the pelagic stratum in seas ranging from 2-6 ft., which

undoubtedly affected our ability to sight some birds. The surveys of shoreline and bay

transects were usually conducted in ~3 ft. seas. We were unable to complete some

transects because of ice encountered in the northem portion and bad weather in the

southern portion of our study area (Fig. ?).

To calculate population estimates, we assumed that all birds and mammals on

transects were counted; however, it was likely that some unknown percentage of birds

and mammals was not counted.

Design of Summer Boat Survey

We surveyed Lower Cook Inlet from 7·23 June 1993, a total of 15 days within a

17·day period. We surveyed 411 transects, using three 25·foot (7.5 m) fiberglass

boats traveling at speeds of 5-10 nmlhr (9-14 kmlhr).

To determine the loc~tions of our transects, we first divided all waters within

Lower Cook Inlet into two strata: shoreline and offshore. We then generated a 2-

minute latitude by 4-minute longitude grid for the study area with the Atlas

Geographical Information System (Strategic Mapping 1992) to separate the starting

locations of our transects (Fig. 5). At the latitude of the study area, the 1,096 blocks

of the grid were approximately 2 nm2 (3.7 km2

).

Shoreline Stratum.~The shoreline stratum was defined'as, all waters within

0.1 nm (200 m) of land and contained a total area of 244.11 km2 (Table 1). Before

selecting transects, we excluded areas of the shoreline stratum that were too shallow

«0.5 ft, 15 em) for our boats. We then placed a 0.1 nm (200 m) wide strip (buffer)

along the shoreline and divided this buffer into segments with the 2 nm2 grid (Fig. 6).

Segments <0.5 nm (0.9 km) were merged with adjacent ones. We randomly chose

30% of these segments for a total of 86 shoreline transects (Fig. 7). The mean length

of transects within the shoreline stratum was 2.3 nm (4.3 km), ranging from 0.6 nm

(1.2 km) to 4.9 nm (9.0 km). We surveyed 30% of the total area of this stratum.

Offshore Stratum.-We used the blocks of the grid to determine the starting

points of our transects. Before randomly selecting the offshore blocks, we examined

eaGh block that intersected either land or the boundaries of the study area to

determine whether the block was,large"enough to 'contain a transect >0.5 nm (0.9 km).

If "I block was too small, it was merged with an adjacent block. If a merged block was

randomly chosen, the transect extended across both blocks (Fig. 7).

When possible, we oriented our transects north to south to run parallel with the

stn)ng tidal currents of Lower Cook Inlet. Thus, we chose the northeastern comer of a

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block as the starting point for a trans'eet and extended ii to the southeastern corner of

the block. If a'bloc'k intersected land, the transect was drawn perpendicular to the

land, thus a few t~nsects were oriented east to west along the northern edge of the

block (Fig. 7). So~etimes adjacent blocks were chosen, resulting in the appearance

of one long transect (Fig. 7). We stopped between transects to collect environmental

data and maintain ~eparation between our sampling units.

, We randoml~ chose 30% (327) of the blocks available in the offshore stratum,

In the field, we found that we were unable to survey two selected transects, so we , '

, surveyed a total of 325 offshore transects.

. The offshorel stratum was post-stratified into two strata: coastal and pelagic,

The coastaLstratu"l was a 3 nm (5.6 km) zone outside of the 0.1 nm (200 m) ,

shoreline stratum (~ig. 6). We classified transects with ~50% of their length within the

3 nm (5.6 km) zdne as coastal stratum, and transects with <50% of their length within

the 3 nm (5.6 km) tone as pelagic stratum. We surveyed 112 transects in the coastal

and 213 transects ihI·the pelagic strata. Transects within the coastal stratum ..averaged

1.8 nm (3.3 km) in length, and we surveyed 2% of the area of this stratum. Transects , within ,

the pelagic stratum , averaged 2.0 nm (3.7 km) in length, and we surveyed 1.6%

of the area of this stratum (Table 1).

I

Design of Winter Surveys

Winter Boat Survey ,

, During winte~ 1994, we reduced our study area within Lower Cook Inlet (Fig. 2).

We divided this area into three strata: shoreline, bay, and pelagic. We surveyed the

shoreline and bay strata on 10 days from 6 February-5 March 1994 using two or three

25-foot (7.5, m) fib,enllglass boats, and we surveyed the pelagic stratum on seven days

from 8 February-10 March 1994 using a 73-foot (22.3 m) charter vessel. Due to gale

force winds and extreme cold temperatures, we were unable to survey all transects

Within, the time available. The harbor in Homer was frozen for approximately two

weeks, and even w~en the winds subsided, we were able to leave the harbor only

when a larger boat broke a path through the sea ice. '

To determine: the locations of our transects, we used methods similar to those

described for the summer survey. We first divided all waters within eastem Lower

Cook Inlet into thre~ strata: shoreline, bay, and pelagic, then we constructed a

2-minute'latitude byl

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4,'-minute longitude grid over the study area to separate the

starting locations of the transects.

, Shoreline Stratum.-The shoreline stratum was defined as all waters within

0.1 nm (200 m) of land and contained a total area of 68.21 km2 (Table 1). For the

winter 1994 surveY,lwe randomly chose 50% of the available transects for a total of 37

shorel,ine transects (Fig. 8). The mean length of transects within the shoreline stratum

was 2.4 nm (4.4km),-and we surveyed '52'7'0 of the total area of this stratum.

:Bay Stratuml-The bay stratum contained all waters >0.1 nm(200 m) from

land, east of 1520

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' W longitude and south of 59°46' N latitude, essentially ,

Kachemak Bay (Fig. 2). We surveyed 61 transects in the bay stratum (Fig. 8), '

averaging 1.7 nm'(3'.1 km) in length (Fig. 8). We surveyed 3.1% of the area of this stratum.

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Pelagic Stratum.-The pelagic stratum consisted of all waters between

15~!028' Wand 152°04' W longitude and north of 59°46' N latitude (Anchor Point). In

this stratum, we surveyed from a 73-foot (22.3 m) vessel, which traveled at 10 nmlhr

(14 km/hr). We surveyed nine lines extending from the southem boundary of the

study area north to 60°02' N (Fig. 8). The lines ranged in length from 14.9-56.0 nm

(27.6-103.8 km) and were spaced four degrees of longitude apart, approximately 2 nm

(3.7 km). We subdivided these lines into 2 nm (3.7 km) segments similar to the bay

transects and randomly selected 50% (85 transects) of these segments for use in our

population estimates (Fig. 8). These segments averaged 2.0 nm (3.7 km) in length,

and we surveyed 2.7% of the area of this stratum (Table 1).

. Surveys Comparing Large and Small Boats.-In the past, many pelagic

surveys of marine birds were conducted from large ships (Gould et al. 1982, Tasker

et al. 1984, Haney 1985, Gould and Forsell 1989). Large ships were usually relatively

slow-moving, and the preferred method was to survey long, straight lines rather than

numerous, short aries. Using a large vessel for our winter pelagic survey allowed us

to compare the differences in. population estimates calculated from a few long lines

surveyed in their entirety with estimates derived from numerous, short transects, as in

our summer 1993 survey.

To compare the differences between long lines and short transects,"we

surveyed nine long lines and randomly-selected 2 nm (3.7 km) segments from within

these lines. We used a Monte-Carlo simulation to randomly-select 50% of the

se~lments (Without replacement) 1,000 times. For each run, we calculated the

coefficient of variation (CV) of the population estimate. We compared these values

with those calculated for the lines by determining how often (%) the CV of the

segments was lower than the CV .of the lines. Surveying only 50% of all possible

segments would require less effort than surveying long lines. To compare population

estimates calculated by both methods using a similar amount of effort, we determined

population estimates using 50% of the segments, then we simulated a larger sample

size (equal effort) by increasing the sample size .in the variance.

Winter Aerial Shoreline Survey ,

To determine abundance of marine birds on the westem side of Lower Cook

Inlet during winter. we re-surveyed Erikson's (1977) aerial shoreline transects on 9

and 16 February 1994 (Fig. 3). Ameson (1980) combined Erikson's (1977) transects

intel 17 units, 14.8-76.3 nm (27-141.3 km) in length, with boundaries easily detected

from the air. We surveyed 11 of these 17 units. Eightwere surveyed completely, but·

thr.Ele of the units (3. 5. and 8) were partially surveyed. Surveys were conducted using

a Cessna 206 flying at speeds of 90-100 nmlhr (167-185 km/hr) at an elevation of

200 ft (61 m). To compare our counts with previous surveys (Erikson 1977, Ameson

19EI0), we counted birds in a 0.2 nm (400 m) wide zone. Two observers"recorded all

birds within 0.1 nm (200 m) on each side of the aircraft. Starting and ending times

were recorded for each sampling unit.

To compare data from the aerial shoreline survey with our boat survey, we also

conducted an aerial survey of Kachemak Bay on 17 February 1994 (Fig. 3).

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Observers on aerial surveys generally'miss more' oirds than observers on boats , .

(Conant et al. 1988). Small, dark birds are especially difficult to see at the high

speeds traveled 'by! most aircraft. We compared the aerial shoreline survey with our

boat survey of the shoreline of Kachemak Bay to develop correction factors to enable

us to compare our ~ata with previous surveys (Erikson 1977, Ameson 1980), We

calculated correCtion factors by dividing the boat estimate by the aerial counts for each

area.. We only caldulated correction factors for species observed on both surveys.

Thus, we could notlobtain correction factors for species difficult to see from the air,

such as Brachyramphus murrelets, which were not seen within the 0.1 nm (200 m)

aerial survey zone. I We then used the correction factors to calculate corrected counts

for the 0.1 nm (2001 m) western shoreline and the combined shoreline survey zones

and for the total (0.2 nm) counts from all three areas (westem, Kachemak Bay, and

combined shoreline1s).

Statistical AnalYSik

Grouping of Data.-Birds that Were difficult to classify by species were

analyzed by speCie~ group (Table 2). For example, short-tailed and sooty

sheaiwaters (Puffin'us tenuirostris and P. griseus) were grouped as shearwaters

.(Puffinus spp.). Gdlls, (Larus and Rissa spp.), shorebirds (Families , Charadriidae and

Scolopacidae), puffins (FratercuJa spp.), and waterfowl were analyzed both by

individual species ahd . , by the four groups. During shoreline surveys, we observed

several species that are not ordinarily classified as marine birds. Of these, we

analyzed only the d~ta for bald eagles (HaJiaeetus Jeucocephalus) and northwestern .

crows (CONUS cauf;nus), species common along the Alaskan shoreline.

, Population Estirnates.-We used a ratio estimator to estimate population sizes , . and variances (Cocrran1977). The population estimate of each species or species

group was calculated for each stratum uSing the formula:

n

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where:

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The areas for each stratum are listed in Table 1. Estimated variances for the

population estimates were calculated as follows:

Y= population estimate for a stratum.

X = total area of the stratum.

Yi = number of birds counted on the ith transect.

x; = area of ith transect.

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2 • 2 2 • E Y; + REx; - 2R E xy;

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n = number of transects sampled in the stratum.

x = mean area of all transects sampled in the stratum. n

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whl~re:

Data from each stratum were treated as a simple random sample to estimate

the population for that stratum. We calculated population estimates for each species

and for all birds by adding the estimates from the three strata. We calculated 95%

confidence intervals for these estimates by adding the variances.

Densities of Marine Birds.-To compare our results with previous surveys of

Lower Cook Inlet (Erikson 19n. Ameson 1980) and with similar surveys of Prince

William Sound in July 1993 (Agler et al. 1994a) and March 1994 (Agler et al. 1994d),

we calculated bi~ densities (birdslkm2

). Densities were determined by dividing our

population estimates by the area of each stratum.

Relative· Abundance of Marine Birds.-'We compared relative abundance of

speiCies in Lower Cook Inlet with that from Prince William Sound. To determine

relative abundance, we determined the total population of marine birds and calculated

the proportion of birds belonging to each major species group for both areas.
Species 'Distribution.-We mapped our sightings with a geographical

information sysierh (Strategic Mapping 1992). This system allowed us to overlay the

distribution of twolspecies.. •

. Comparison with Prince William Sound.--To compare the results of our

Lower Cook Inlet Survey with a similar region, we used the results of Prince William

I Sound surveys conducted in July 1993 (Agler et al. 1.994a) and March 1994 (Agler et

al. 1994d). To mihimize between year variation, we compared surveys conducted .

during differentmbnths of the same year (ie.--June and July) rather than two surveys , I .

conducted in the same month but two or three years apart.

Bird distribJtion by month may be affected by breeding phenologies of various

species. We e~arhined the differences between June and July by comparing surveys

of Prince William Sound conducted during June and July 1990. To determine the

proportion of diffe(ence, we divided the June population estimates by the July

population estimat~s (Klosiewski and Laing 1994, K. Laing, U.S. Fish and Wildlife

Service, unpubl. dkta). Scoters, Brachyramphus murrelets, and murres showed

notable differenceS between months. The population estimates of scoters and

Brachyramphus m~rrelets were higher during July. The murre estimate was lower in

July: but overall; tile murre population estimates tended to be highly variable among

years. \ I ' .

, The shoreli~e strata of both Lower Cook Inl.et and Prince William Sound were

defined using the same criteria, but the coastal and pelagic strata were defined

differently. Thu~,';"'e compared the differences between the shoreline strata of the two

areas directly, but ~o compare the coastal and pelagic strata, we combined them into

one offshore stratum. . .

I Improveme1nt of the'Survey.••Precision can be improved by increasing sample

size 'and using strJtification to minimize variances within strata (Pojar et al. 1995f In

a multi-species sulvey, such as this one, it is often impossible to stratify in the most

appropriate mann~r for each species. Prior to the June 1993 survey, we divided

Lower Cook Inlet ihto two strata: shoreline ~O,1 nm from shore) and offshore ,

(>0.1 nm from sholre). We then post-stratified by dividing the offshore stratum into a

coastal ~3 nm of Shore) and a pelagic strata (>3 nm of shore), and we used this

design to calculatel

the population estimates presented here (Table 3). This design

provided fairly goob CV's for some species but not for all'. To make recommendations

for fyture surveys, ,we examined several other stratifications to determine whether the

precision of the estimates would be improved by re-stratification of future surveys

(Table 3). " I " ' ..

When we examined the distribution maps from the June 1993 survey, we found

that the highest bo~nts of birds were on transects in the east and southeast portions

of the Inlet. To re-1stratify, we altered the original stratification (shoreline and offshore I

strata) by dividing-the inlet into east and west strata, which gave us four strata

(Fig. 9). We then kdded a coastal stratum to this design, resulting in 'six strata

(Fig. 10). BecausE! there were fewer birds in the northern part o/Lower Cook Inlet, we

divided the Inlet ',atIAnchor Point and placed Kamishak and Kachemak Bays into

separate strata, rejUlting in seven strata (Fig. 11). Because many birds were near

I . 9 •
RESULTS

SUlmmer Boat Survey .'. . • We observed 56 bird (Appendix A) and 6 marine mammal (Appendices Band

C) species in Lower Cook Inlet during June 1993.

Marine Birds

Population Estimates of Marine Birds.-We estimated that 798.042 +

19~i,555 marine birds were in Lower Cook Inlet during June 1993 (Table 4). Of these,

37,333 + 13,586'birds were in the shoreline stratum, 254,975 ± 168,684 birds were in

the coastal stratum, and 505,733 + 97,995 birds were in the pelagic stratum (Table 5).

Common murrewas,the most abundant species (168,446 ± 135,747 birds) followed by

fork-tailed storm-petrel (Oceanodrpma furcata; 113,804 ± 60,101 birds; Appendix A).

Population estimates of individual species and/or major species groups are listed in

Table 4 and Appendix A.

colonies during the summer breeding season, we also examined three re-stratifications

based upon distance (5, 10, and 15 km) from colonies of >500 birds (USFWS 1995.

Figs. 12-14). Because of our initial results, we examined precision by increasing the

size of the coastal stratum to 5 nm (Fig. 15).

Estimates may also be improved by increasing effort where the majority of the

spl~cies are found and reducing effort in areas of low density (Cochrai11977). Thus, if

we re-stratify in future surveys, we would also re-allocate effort to improve precision.

To simulate this, we distributed transects among strata by two methods. First. we

re-allpcated transects by the percentage of the total marine birds found in each

stratum. We also determined which species contributed most to the variance of the

marine bird estimate by calculating population estimates without various species or

spElcies groups. Common murres (Uria aalge) contributed the most to the variance,

so in the second method, we allocated transects by the percentage of murres in each

stratum. The resulting sample sizes of transects (n) were used in the variance

calculations for each stratum. . . '

To compare among stratifications, we calculated the CV's of species and

species groups with population estimates >500 birds then ranked the CV's by

stratif.ication designs. We then summed all ranks for each stratification and calculated

a mean rank for each stratification.

Survey Frequency.-There are two major reasons to continue to conduct

surveys: (1) to determine effects of an environmental perturbation, such as an oil spill;

and, (2) to determine long-term trends in population abundance. Klosiewski and Laing

(1994) examined the first possibility, which we will discuss later. To examine how

OftEln surveys should occur to determine long-term trends in abundance, we conducted

a power analysis to calculate our ability to detect trends (Gerrodette 1987, eq. 20).

We, approximated power for different combinations of CV (0.2, 0.3, 0.4, and 0.5) and

confidence level (ex = 0.05, 0.10, 0.15, and 0.20). .

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Densitil!S ot Marine Birds.--During summer 1993, we estimated that density

was 57.9 birds/krnj (Table 6). The highest densitiesoccl1rred in the shoreline stratum

(152.9 birds/krn2

) followed by the coastal (71.6 birds/km2) and pelagic strata

(56.7 birds/km2, T~ble 6). The highest overall density was estimated for alcids

(22.1 birds/km2) followed by tubenoses (20.3 birdslkm2). However, the species group

with the highest pehsity varied among strata (Table 6). The highest density of alcids

occurred in the co~stal stratum (29.3 birds/km2

). In the shoreline stratum, gulls

(89.6 birds/km2

) ha~ the highest density, much higher than the 13.1 birds/km2

estimated for aICid~. In the pelagic stratum, tubenoses had the highest density (26.2

birdS/km2)·1 ' Relative Abundance of Marine .Birds.-We found that the most Common

species group (Ta~le 7) during summer 1993 was alcids (38.1 %), consisting of murres

(21.2% of total), puffins (8.4% of total), and Brachyramphus murrelets (7.3% of total).

The second most c:ommon species group was tubenoses (35.0%), consisting of

sheaiWaters and fulmars (20.7% of total) and storm-petrels (14.3% of total). Gulls

, (16.2% of total) wa~the third most common species group. When we examined these

data by stratum, 'we found that the most common species group in the shoreline . , stratum was gulls (58.6%). AICids (41.0%), consisting of mostly of murres (32.7% of , total), was the most common species group in the coastal stratum, and tubenoses

(51.8~/o), consistihglOf shearwaters and fulmars (29.3% of total) and storm-petrels

(22.5% of total), was the most common group in the pelagic stratum.

Species Distribution.-Overall, marine birds were seen throughout the Inlet

(Fig. 16). The tranSects with the highest counts of birds were located near shore, and

most of these wereInear breeding colonies. Two transects were near a large colony

at Chisik Island, ana two other transects were on either side of a large colony in

Kachemak Bay. I ' '

Tubenoses were sighted throughout the pelagic waters, but they were most

abundant in the ea~tern portion of the study area, primarily the southeastern corner , (Fig. 17). SheaiWaters were common throughout the pelagic waters, but most

sightings were inthb eastern part of the study area (Fig. 18). Scattered sightings of

northern fulmars (FUlmarus glacialis) were recorded throughout the eastern portion,

but most sightings Were alarm the southeastern border of the study area (Fig. 18).

Distribution of stom\-petrels was similar to that of fulmars (Fig. 19). Sightings of

storm-petrels were /nost common along a line corresponding to one of the large tide

rips found in the lnl~t (Fig. 4, Burbank 1977). '

Cormorants ~Phalacrocorax spp.) were usually sighted along the shoreline and

were most often seEln near small colonies in Kamishak and Kachemak Bays (Fig. 20).

Waterfowl were alsO usually distributed along the shoreline,and the largest estimates

were ,from the western side of the Inlet (Fig. 21). '

Although- gUII$-{mostly black-legged kittiwakes, Rissa tridactyla, and glaucouswinged gulls, LartJs glaucescens) occurred in small numbers throughout the Inlet,

counts were largest on transects near colonies (Fig. 22). Terns (Sterna spp.) were

only sighted in the northern end of the study area and within Kachemak Bay (Fig. 23).

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Several oHhese sightings were of Aleutian tems (S. aleutica), which rarely nest in

Kachemak Bay (G. West, pers. commun.). -

Overall, alcids were distributed throughout the Inlet, but most were observed in

thel eastem part of the study area (Fig. 24). Murres were scattered throughout the

ama with high numbers observed at the mouth of Kachemak Bay and in the

southeastem comer of the Inlet (Fig. 25). Numerous Brachyramphus murrelets were

observed near the mouth of Kactlemak Bay, but small numbers were sighted

throughout the Inlet (Fig. 26). Homed (Fratercula comiculata) and tufted puffins

(F. cirrhata) were mostly sighted in the eastem portion of the Inlet (Fig. 27), a

dis.tribution similar to that observed for murres (Fig. 25) and shearwaters (Fig. 19).

The largest counts of homed puffins were located near Anchor Point at the mouth -of

Kachemak Bay; whereas, the largest numbers of tufted puffins were observed in the

southeastem corner of the Inlet near a large tufted puffin breeding colony. Pigeon

guillemots were usually observed along the shoreline, but a few observations occurred

in pelagic waters near Anchor Point (Fig. 28).

Sea Otters

Population Estimates of Sea Otters.-From our summer 1993 survey, we

estimated that 5,914 ±3,094 sea otters were in Lower Cook Inlet (Appendix B). We

estimated that 520 ± 534 otters were in the shoreline stratum, 2,855 + 2,014 otters

were in the coastal str~tum, and 2,539 ± 2,287 otters were in the pelagic stratum.

Densities of Sea Otters.-We estimated a density of 0.4 otterslkm2 during

summer 1993. Density was highest in the shoreline stratum (2.1 otterslkm2

) followed

by the coastal (0.,8 otters/km2

) and pelagic strata (0.3 otterslkm2

). In the combined

offshore stratum, we estimated a density of 0.4 otterslkm2

•

Species Distribution.-Most sea otters (Fig. 29) were observed within 8 nm

(14.8 km) of land and along thesouthem edge of Kachemak Bay, although a few -

sightings occurred in the more exposed sections of Kamishak Bay. There was one

observation of two otters in the middle of the Inlet, approximately 31 km from land.

Winter Boat Survey

During our February-March 1994 survey, we observed a total of 43 species of

birds (Appendix A) and 4 species of marine mammals (Appendices B and C).

Marine Birds

Population Estimates of Marine Birds.-We estimated that 122,946 ±

25,804 marine birds were in the eastern portion of Lower Cook Inlet during winter

1994 (Table 4). Estimates for the shoreline, bay, and pelagic strata were

14,611 ± 2,792; 75,310 ± 21,069; and 33,025 ± 14,634 birds, respectively (Table 8).

Waterfowl was the' most common species group with a population estimate of

56,607 ± 19,985 birds. Most of these were scoters (29,408 ± 11,281 birds). The

sel:ond most common group was alcids with a population estimate of 40,271 ±

12,810 birds. Most alcids (63%) were murres, but 29% of the aleids consisted of

Bfi~chyramphus murrelets (Table 4). . -

12

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33.6 birdslkm2 in t~e eastern porticnof tower Cook Inlet (Table 9). Densities were

214,2,61.7, and 13.9 birds/km2 in the shoreline, bay, and pelagic strata, respectively,

Waterfowl had the Ihighest density (15.5 birds/km2

) of any species group followed by

alcids (11.0 birds/km2). Waterfowl had the highest densities in the shoreline

(132.5 birds/km2

) ~nd pelagic strata (7.0 birds/km2

), but alcids had a similar density in

the bay stratum (albids, 25.7 birds/km2

; waterfowl, 25,3 birds/km2

). ' ,

, Relative Ab1undance of Marine Birds.--The most common species group

(Table 10) observeb in eastern Lower Cook Inlet during winter 1994 was waterfowl

(46.0%), consistingl

of scoters (23.9% of total), oldsquaws (Clangula hyemalis, 9,0% of

total), eiders (Somateria spp. and Polysticta stelleri, 4.7%of total), and goldeneyes , I

(Bucephala clangula and B. islandica, 3.0% of total). The second most common '

species group waslalcids (32.8%), consisting of murres (20.7% of total),

Brachyramphu5 murrelets (9.5% of total), and pigeon guillemots (2.4% of total), The .. , I '

gull species group was the third most common (13.1 %). .

Species Di~tribution.-Marinebirds were distributed in limited numbers I '

throughout the study area during winter 1994 (Fig. 30), although most birds were

concentrated withinl

protected bays and fjords on the southern shore of Kachemak

Bay. ' , I '

, Loons (Gavia spp., Fig. 31) and grebes (Podiceps spp., Fig. 32) were most

common along the ~outhem shore of Kachemak Bay. Unlike most species groups.

cormorants were fo'und throughout the winter study area (Fig. 33), and they were as

common along the horthwestern shore of Kachemak Bay as along its southern, more

protected side. A r1umber of cormorants were also obserVed on several of the pelagic

transects, including1transects in the center of the Inlet. -

: Most waterfowl were sighted along the southem side of Kachemak Bay

(Fig, 34). Steller;s ~iders (Polysticta stelleri, Fig. 35) were found in the protected I

waters of Kachernak Bay, near Seldovia and Homer; whereas, common eiders

(Somateria mollissitna, Fig. 35) were observed in the open area off of Anchor Point,

and one transect in the pelagic stratum had a count of >50 common eiders. Harlequin

ducks (Histrionicus histrionicus, Fig. 36) and goldeneyes (Fig. 37) were most common

along the protected coastline of southern Kachemak Bay. Oldsquaws were frequently

observed in the protected waters of Kachemak Bay, but a number of individuals were

also sighted on thelpelagic surveys north of Anchor Point (Fig. 38). Scoters were

sighted on both sides of Kachemak Bay. Several large groups were observed near

Anchor Point and Homer and within the protected bays and fjords of the southern

shor~ (Fig. 39). , I ' " , Although gul~ (mostly glaucous-winged gulls) were observed in small numbers

on 61.2% of the pelagic transects, the largest numbers of gulls were observed on the

mudflats east of Holner (Fig. 40). " ' ,

Althoughalci~s were also observed throughout the study area, most sightings

were located within 18 nm (15 km) of Homer (Fig. 41). The.largest counts of murres

_ occurred along the southern shore of Kachemak Bay (Fig. 42), and most

Brachyramphus mutrelets were observed west of Homer (Fig. 43). The distribution of " ' ,I

13
pigeon guillemots (Fig. 44) during the winter appeared to be more pelagic than during

summer 1993 (Fig. 28). Highest densities of guillemots during the winter were in the

bay stratum (Table 9); whereas, highest summer densities were in the shoreline.

stratum (Table 6).

Surveys Comparing Large and Small Boat Methods.-When we calculated

population estimates for the pelagic stratum using nine long lines and compared them

witl1 85 randomly-chosen, short segments, we found that the estimates and 95%

confidence intervals were similar (Table 11). Using the data from the long lines, we

determined that there was a total of 25,484 ± 17,727 birds in the pelagic stratum.

When we calculated the estimate from the short segments, we estimated that

33,025 ± 14;634 birds were in the pelagic stratum. Some species groups (Table 11),

such as murres, had almost identical estimates (5,417 ± 1,988 birds, lines;

5,391 ± 1,845 birds, segments).

From a Monte-Carlo simulation, we found that the CV of the estimate of total

marine birds calculated from the segments was lower than that calculated from the

linEtS 100% of the time (Table 12). When estimates were calculated from segments,

seven species groups had lower CV's >85% of the time. When estimates were

calculated from lines, eight species groups had lower CV's >65% of the time. When

we simulated equal effort, we found that 11 of the 15 species groups had lower CV's

>90% of the time and 13 of the groups had lower CV's >50% of the time when

estimates were calculated from short segments instead of long lines (Table 13).

Sel:l Otters

Population Estimates of Sea Otters.-During winter 1994, we estimated that

1,104 ± 592 sea otters were in the eastem portion of Lower Cook Inlet (Appendix B).

We estimated that there were 112 + 107 otters in the shoreline stratum, 933 + 583

ottms in the bay stratum, and no otters were recorded in the pelagic stratum.

Densities of Sea Otters.-We estimated that the overall density of sea otters in

our study area was 0.3 otterslkm2

• The highest densities (2.5 otters/km2

) were found

in the shoreline stratum; whereas, thebay stratum had a density of only

0.8 otters/km2

• In the combined offshore stratum, density was 0.3 otterslkm2 •

Species Distribution...Although a few otters were observed off of Anchor Point

near the mouth of Kachemak Bay, most were seen in protected, ice-free waters along

the southeIT.! shore of Kachemak Bay (Fig. 45). .

Winter Aerial Shoreline Survey

Marine Birds

Number or Birds Observ8d.-During the winter 1994 aerial shoreline survey of

the western side oft.ower Cook-inlet, we'counted a'total of 1,486 marine birds within

the 0.1 nm (200 m) zone comparable to the shoreline stratum used in our small boat

surveys (Table 14). Eighty-three percent (83%) of these birds were waterfowl.

Oldsquaws' were the most commonly sighted species (35% of waterfowl); whereas,

harlequin ducks, Steller's eiders, and scoters were found in approximately equal

14

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proportions (14, 19, and 17% of waterfowl, respectively). No alcids were counted

within the 0.1 nm (200 m)zone.ln, the 0.2 nm(400 m) .zone, we counted

4,807 marine bitds (Table 13 and Appendix D). Waterfowl made up 93% of these

birds. • I . . We also sureyed three shoreline sections in Kachemak Bay originally surveyed

by Arneson (1980)., During this aerial survey, we counted 7,092 marine birds within

the 0.1 nm (200 m~ zone (Table 14). These birds consisted of waterfowl (51.50,;') and

alcids (34.1 %). Most of the waterfowl were mergansers (32.9%) and scoters (27,5%);

all of the alcids welre murres. Within the 0.2 nm (400 m) zone' of Kachemak Bay

(Appendix D), we dounted 15,775 marine birds (Table 14). Alcids (7,310 birds)

outnumbered watekowl (6,525 birds).

When we,cdmbined counts, we tallied 8,578 marine birds in the 0.1 nm (200 m)

zone and 20,852 b:irds in the 0.2 nm (400 m) zone (Table 13). These birds consisted

mostly of waterfowl and alcids.

Densities of Marine Birds.-Thoe highest bird densities on the western aerial

shoreline survey' w~re waterfowl (9.8 birds/km2

, 0.1 nm zone; 18.0 birds/km2, 0.2 nm

zone). No alcids Were sighted in the 0.1 nm (200 m) zone, and only two murres were

seen within the cd nm (400 m) zone. Highest waterfowl densities (47 birds/km2

) were

observed along lh~ Iniskin Peninsula, and these were all sea ducks (Table 15).

In the 0.1 nrh (200 m) zone in Kachemak Bay, the highest density was

recorded for waterfpwl (62.2 birds/km2

). In the 0.2 nm (400 m) zone, the waterfowl

density remained similar (60.0 birds/km2) to the 0.1 nm zone; whereas, the density of

alcids increased frdm 41.3 birds/km2 in the 0.1 nm (200 m) zone to 67.2 birds/km2 in , , the 0.2 nm(400 m) zone.

Correction j:actors.-We combined data from the 0.1 nm (200 m) aerial survey

zone with data frortJ, the small boat shoreline survey of Kachemak Bay to develop

correction factors (fable 16). Correction factors ranged from 0.4 for eiders to 21.3 for

buffleheads (Budephala albeala). We could not calculate a correction factor for

Brachyramphus mJrrelets, because this species group was not sighted within the

0.1 rim (200 m) aetial survey zone. Correction factors> 1 indicated that the small boat

surveys estimated greater number of birds in Kachemak Bay than the aerial

shoreline survey cdunted, while corrections factors <1 indicated that densities from the

aerial shoreline sutey were greater. Most species or species groups (71 %) had

correction factors >1.

Sea Otters ' .1 . •

During the aerial shoreline survey of the westem side of Lower Cook Inlet, we

counted 68 sea·ottl!lrs in the 0.1 nm (200 m) zone (Table 13). Estimated density

within this zone wah 0.5 otters/km2

. In the 0.2 nm (400 m) zone, 186 sea otters were

counted, with adehsity of 0.8·otterslkm2

.

In Kachema~ Bay, 72 sea otters were counted in the 0.1 nm (200 m) zone, with

a density of 0.5 Qtt~rslkm2. In the 0.2 nm (400 m) zone, 283 sea otters were counted,

and density was 2.6 otterslkm2.

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Comparison with Prince William Sound .

.Densities of marine birds from a similar survey of Prince William Sound during

July 1993 (Table 17) and March 1994 (Table 18) were calculated for comparisons with

those in Lower Cook Inlet (Tables 6 and 9). Density of total marine birds in Prince

William Sound during July 1993 was 41.3 birdslkm2

• We found that the species group

with the highest total density during summer 1993 was alcids (21.0 birdslkm2

), mostly

Bra!chyramphu5 murrelets (17.8 birdslkm2). The summer density in the shoreline

stratum was 148.7 birdslkm2

, and the density estimated for the offshore stratum was

30.:5 birdslkm2

• During winter 1994, the total marine bird density within Prince William

Sound was 35.7 birdslkm2

• The species group with the highest total density was

waterfowl (14.8 birds/km2

). During the winter, the density of birds in the shoreline

stratum was 190.1 birdslkm2

, and the bird density within the offshore stratum was

20.2 birdslkm2. .

Relative abundances were also calculated (Tables 19 and 20). Alcids had the

highest relative abundance during summer 1993 (50.8%), and most alcids were

Bra'chyramphu5 murrelets (42.9% of total). During winter 1994, the relative

abundance of alcids declined to 28%; whereas, the relative abundance of waterfowl

increase to 41.3%. Gulls were the second most abundant species group during the

summer (31.4%) but dropped to third during the winter (20.4%).

Improvement of the Survey

We found that mean CV's of the various ra-stratifications ranged from 0.46-

0.49; whereas, the mean CV from the original stratification with no re-allocation of

effort was 0.38 (Table 21). Although the original stratification design had the best

mean CV, it ranked highest (worst, Table 22). When we simulated re-allocation of

transects based on bird abundance as we did for the other stratifications, the rank of

the original stratification design tied for the best ranking with the east-west restratification including shoreline, coastal, and pelagic strata (Fig. 10).

When we allocated transects by the species having the largest effect on the·

variance (common murre), mean CV's rangedtrom 0.38-1.97 (Table 23). Both original

straltifications had the lowest mean CV's and held the top two ranks (Tables 23 and

24). By comparing the mean CV's for the groups in each re-stratification (Tables 21

and 23), we found that transect allocation based on common murre distribution

resulted in higher CV's.

Survey Frequency

To determine optimum survey frequency, we conducted a power analysis to

estimate the pro6ability of detecting trends in abundance using linear regression from

a given number of samples (Gerrodette 1987). If all other parameters are equal, we

found that power is~termined by the' number of'sUlveys conducted in a given period

of time (Figs. 46-47). Thus, biannual surveys would reveal trends in population

abundance earlier than surveys conducted every third year. To provide an accurate

reclJmmendation of survey frequency, we should know hOw long monitoring will

persist.

16

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For biannual surveys with CV = 0.3 and 0: = 0.10, power to detect an average I '

annual change of r0% would be 49% over 10,years (5· surveys), >99% over 20 years

(10 surveys), and >99% over 30 years (15 surveys, Table 25). If surveys are

conducted every t~ird year,' power to detect the same 10% annual trend would be '

32% over 10 years (4 ,surveys), 74% over 20 years (7 surveys), and >99% over 30 I ' '

years (10 surveys). Biannual surveys conducted over 30 years would have 88%

probability of detedting a trend when the average rate of change is only 5%

(Table 26), but sureys conducted every third year for the same time period would

only, have a 45% chance of detecting such a trend. . ' , , Power is affected by CV. When we compared CV's for two different rates of

change (Tables 24\ and 25), we found that when the CV was high (0.5) the power of "

biannual surveys to detect an average annual change of 10% was low (16% over . , 10 years, 57% over 20 years, and 96% over 30 years). When the CV was low, power , , f increased to 49% over 10 years and >99% for both 20 and 30 years 0 surveys. If I , '

surveys were conducted , , every third year and the CV was 0.5, power to detect a 10%

annual trend woul9 only be 12% over 10 years, 29% over 20 years, and 57% over 30

years, but when the CV was reduced to 0.2, power increased to 32% over 10 years,

74% over 20iyear~, and >99% over 30 years. Thus, decreasing the CV, would

increase our ability' to detect trends.

DISCUSSION

The results of

, these surveys represent the first estimates of marine bird

abundance calculated for Lower Cook Inle,t in 15 years. Developing these estimates

was a vital step in bur understanding of the significance of this area to the marine bird

populations of Ala~ka. For example, our summer estimate of marine birds in Lower

Cook Inlet was ov~,r twice the estimate calculated for Prince William Sound in July

1993 (Agler et al. 1994a), demonstrating the importance of Lower Cook Inlet withinthe

Gulf of Alaska eco~ystem for breeding and non-breeding marine birds and sea otters

during both summer and winter.'

During sumrher, most birds were distributed along the shoreline and on the

eastem side of LoJ..er Cook Inlet. Birds frequented the area where the Alaska Coastal , Current enters the Inlet (Burbank 1977, see Fig. 4), bringing in nutrient-rich waters and

causing upwelling ~nd increased mixing. In winter, birds concentrated in protected,

ice-free bays, espebially those along the southem shore cif Kachemak Bay. Any

environmental alterktion of these areas, such as an oil spill, could greatly affect the

marine bird and se~ otter populations of the Inlet.

The estimat&s presented here are based on a new technique, differing from

previous surveys u~ed to estimate seabird abundance. We used small, fast boats to

survey a large 'num:ber of short, widely-distributed; randomly-selected transects, a

method developed in Prince William Sound, Alaska (Klosiewski and Laing 1994). , Most previous studies used one large vessel to survey long, systematically-placed,

lines in pelagic watbrs (Tasker et al. 1984, Gould and Forsell 1989). Our study area

covered both shor~line and pelagic habitats. Small boats allow greater

17
, maneuverability in shallow waters, increasing our ability to survey shoreline habitats.

where many breeding and non-breeding birds congregate. Pennington and Voistad

(Hl94) examined survey data on marine fishes and found that reducing the size of the

sampling unit, then using the time saved to sample more locations, yielded more

pmcise estimates of population parameters. The speed of the small boats reduced

travel time between transects allowing us to sample a large number of short transects.

thus, increasing the precision of our estimates. '

As with all sampling methods, there are biases that might affect our estimates.

WE~ counted birds continuously along each transect, a controversial technique

discussed by several authors sampling from larger vessels (Tasker et al. 1984, Haney

1985, Gaston et al..198?, Gould and Forsell 1989, Spear et al. 1992, van Franeker

1994). Continuous sampling of birds flying across transects causes an overestimate

, of the abundance of some species by measuring bird flux instead of density (van

Franeker 1994). To minimize the problem of counting birds flying across transects, we

used a small survey window, two-thirds of the width and only one-third the length

pmviously counted forward of the vessel. Recently developed methods, using

"snapshot" counts (Gould and Forsell 1989, van Franeker 1994) to limit the number of

flying birds recorded, may reduce this problem. If "snapshot" counts are employed in

future surveys, the two methods should first be used simultaneously to develop

correction factors to allow compansons among years..

We assumed that we counted all birds and mammals on the transects;

however, it was likely that some unknown percentage of birds and mammals was

missed, causing us to underestimate population abundance. For instance, we might

not see a bird leave the transect because of the boat's approach. Udevitz et al.

(1995) conducted a pilot study of ,the sightability of sea otters from similar small boat

sUlveys in Prince William Sound. I They found that observers on boats only counted

70% of the otters seen from land. Due to small sample size, Udevitz et al. (1995)

advised against application of their results to other studies (Udevitz et al. 1995), so we

have chosen t6 remain conservat'ive and have not corrected our sea otter estimates

upward. For most bird'species, studies of this type have not been done, so we have

no correction factors for our estimates.

Comparison between Summer 1993 and Winter 1994 Surveys

Total density of marine birds decreased by 43% from summer to winter. This

large decline between seasons occurred mostly in the offshore stratum, reflecting

changes in the species composition from summer to winter. The density of tubenoses

decreased by 42% in the offshore stratum, thus, summer birds, such as the

shearwaters, wh~ breed in the southem hemisphere during our winter months,

departed and were replaced by over-wintering birds. Densities of tubenoses, gulls,

and alcids decreased~whereas, densities of waterfowl increased three-fold during the

winter, indicating that the Inlet was an important wintering site for waterfowl. Densities

of gulls and alcids decreased by approximately 50% from summer to winter. For gulls,

the decrease was due to a 100% reduction in the density of black-legged kittiwakes,

and for alcids, the decrease was due to a 46% decrease in murres. Some species

18

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(jaegers, terns, anti puffins, summer; grebes, winter) ware observed in only one ,

, season, emphasizihg the significance of Lower Cook Inlet as yearcround habitat.-

'Differences bbserved in densities between seas.ons were also true by stratum.

The shoreline ,stiat'um was important for gulls during the summer, probably because of

the colonies loc~te~ i1, this stratum. The offshore stratum was an important site for

tubenoses during the summer, providing important feeding habitat for these mostly

non-breeding birdsl (Piatt 1993). The,shoreline stratum was the preferred habitat for,

waterfowl during' bQth seasons, and waterfowl was the most abundant group observed

in both shoreline ahd offshore strata during the winter, adding support to the '

significance of Lb~er Cook Inlei as critical habitat for wiritering waterfowl. The

importance of Lower Cook Inlet as year-round habitat for some species was

emphasized by thel similarity of the relative abundance of alcids in the offshorestratum

during summer and winter., '

Evidently, s~a otters remained within the Inlet year-round, because their

densities were simi,lar in both winter and summer. Although sea otters can feed in •

water depths of ~8? m (Schneider 1976) and thus could be found anywhere in Lower

Cook Inlet, our Observations showed that sea otters preferred the shallower waters of

the shoreline stratulm, especially the protected bays and fjords in Kachemak Bay

(Fig. .29). '

Comparison with Previous Surveys "

, 'During sur:nmer 1993, we estimated a density within the shoreline stratum

(152.9 birdslkm2

) silmilar to Ameson's (1980; 130 birdslkm2

) density from aerial

surveys of Lower dook Inlet during 1976-78. However, our density estimate for the

pelagic stratum wa~ twice that estimated by Arneson (1980; 26 birdslkm2

). Both

surveys found tha.t kea ducks represented the highest proportion of birds in the I ,

shoreline stratum of the eastern portion of Lower Cook Inlet during winter, but our

density estimates Were 4.5 times greater than those estimated by Arneson (1980, 47

birds/km2

, We

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believe the bird populations of Lower

:.

Cook Inlet have increased

markedly in the 15 years between surveys. Recent counts of colonies within Lower

Cook Inlet indicated that numbers of breeding pairs of black-legged kittiwakes and

common murres ha~e decreased since 1976 (Slater et al. 1995). Marine bird '

populations in nearby Prince William Sound also have decreased in the last 20 years

(Klosiewski and Laihg 1994). Thus, it is likely that the bird populations of Lower Cook

Inlet have either terhained stable or decreased as well. '

The differendes in densities observed between our survey and Arneson's (1980) I

were probably due to methodology. Arneson (1980) conducted mostly aerial surveys

of Lower Cook Inlet~ Aerial surveys tend to underestimate population size (Conant et

al. 1988). We al~o!lfoundthis to'be true when' we compared our small boat shoreline

survey with our aerial survey of Kachemak Bay during winter 1994. Our results

indicated that obserjvers on the aerial survey counted only 70% of the birds. Thus,

Arneson (1980) probably underestimated population abundance.

19
Sea otter populations were nearly eliminated from Lower Cook Inlet in the early

1900's (Schneider 1976). Only a few otters persisted in the Augustine Island area. In

the! last 25 years, the otter population has expanded northward around the Kenai

Peninsula and eastward from Kamishak Bay to include Kachemak Bay (Schneider

1976). DeGange et al. (1990) conducted an aerial survey after the Exxon Valdez oil

spill in 1989 and reported densities of 1 otterlkm2 along the southern shoreline of .

Kamishak Bay. We calculated similar densities from our winter aerial shoreline

survey, indicating that the sea otter population of Kamishak Bay has remained fairly

stalble over the last four years.

The densities we estimated for sea otters in Kachemak Bay during summer

1993 and winter 1994 were higher than previous surveys (Schneider 1976, DeGange

1990), indicating that the otter population of Kachemak Bay has increased over time.

Observers on an aerial survey of Kachemak Bay in 1976 counted 75 otters in Port

Graham and only 6 otters east of and including Seldovia (Schneider 1976). DeGange

et al..(1990) reported densities of <1-2 sea otters/km2 east of and including Seldovia.

Schneider (1976) hypothesized that otters in Kachemak Bay were a nonbre!eding population. During our surveys, pups were commonly seen along the

sOIJthern shore of Kachemak Bay, indicating that breeding now occurs in this area.

Our sighting of a pair of otters in the middle of Lower Cook Inlet during summer 1993

supports Schneider's (1976) hypothesis that sea otters may move between Kamishak

and Kachemak Bays.

Winter Aerial Shoreline Survey

Our estimates of bird density from the combined eastern and western aerial

shoreline surveys of Lower Cook Inlet during winter 1994 were 180% higher than

Arneson's (1980). This difference was likely due to differences in areas covered

during the two surveys, especially in the eastern portion of the Inlet. Arneson (1980)

covered 17 shoreline sections, but we were only able to survey 11 of these. On the

eastern side, we only surveyed the three sections in Kachemak Bay where Arneson

(1980) found birds to be most abundant. By surveying areas with the highest

numbers of birds, our densities for the eastern portion of the Inlet may be artificially

high. Our estimate for the westem shoreline (19.3 birds/km2 ) was similar to Ameson's

(1980) estimate of 16.0 birdslkm2. .

Kachemak Bay appears to be more important for wintering birds than Kamishak

Bay on the westem side of the Inlet. Ameson (1980) also noted a marked difference

in densities between the eastem and westem sides of Lower Cook Inlet. Arneson's

(1980) eastem section had a density of 47 birdslkm2

; whereas, the westem side only

had a density 0116 birdsJkm2 (Ameson 1980). Kachemak Bay is more protected than

Kamishak Bay from winter winds and tends to be free of ice.

Comparisonof--our estimates of-abundance from the small boat shoreline

survey with'counts from the aerial survey of Kachemak Bay demonstrated that the

densities calculated from aerial surveys generally underestimate bird abundance.

(Table 14). Observers on the aerial survey completely missed some of the smaller "

species, such as Brachyramphusmurrelets. Conant et al. (1988) also found that

20

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aerial observers underestimated waterfowl abundance. Correction factors developed

for species that'w~re sighted in b.oth Kachemak Bay surveys varied overall by 140%

of the estimate (Table 16). The differences among species support the importance of , developing correction factors for each species. Observers on the aerial survey

underestimated ;th~ number of birds by 30%. For some species, such as eiders and

murres, counts frofn the aerial survey were higher than estimates from the boat

survey, but this m~y be due to differences in counting techniques between surveys.

The winter 1994 abrial survey observers counted all members of a large flock,

especially in smallIbays; whereas, observers on the small boat survey counted only

those birds within re survey window. ,

Surveys Comparing Large and Small Boat Methods

When sampling a species with an aggregated distribution, a large sample unit

is less precise tha~ smaller units (Green 1979, Pennington and V01stad 1994).

Because of the aggregated distribution of most seabird species, population estimates

calculated from long lines surveyed by a large vessel should have larger confidence

intervals than numbrous, short segments for the same amount of effort. Thus, the

similarity between bur winter estimates from long lines and short segments for some

speCies (ie.--scote~s, murres) was not expected. For aggregated species such as

waterfowl, we calculated better CV's from the short segments than from the long lines.

Evidently, other sp~cies such as murrelets had a more uniform distribution than

expected, because: the CV's from their population estimates were lower from the long,

lines. Our maps of winter bird distribution (Figs. 23-37) corroborate these findings.

The similarity between results of the two methods supports the validity of using

small; fast boatsfo:rthistype of marine bird survey. With good weather, small boats

would obtain similar results as a large vessel with less effort. Small boats only . . , '

needed to sample 50% of the area sampled by a large vessel to obtain comparable

estimates. When We simulated equal effort, we found that most estimates based on

data from segment~ had lower CV's. This was to be expected because the sample

size of the segments was larger. I, '

Comparison with Prince William Sound

Summer edat Survey.-Our summer 1993 estimate of marine birds in the Inlet

(798,042 ± 195,555) was over twice the estimate calculated for a similar survey of

Prince William Souhd during July 1993 (371,327 ± 58,189 birds, Agler et al. 1994a).

Because of the diff~rence in size between the two areas (Lower Cook Inlet was 1.5

times larger), comparing densities between areas is more meaningful. Our summer

1993 total density ~stimate from Lower Cook Inlet (57.9 ± 14.2 birdslkm2

) was 28.7%

higher than the dertsity estimated for Prince William Sound (41.3 + 6.5 birds/km2

).

Prince William S6ul,d has long been considered an important area for marine birds

,(Agler et al. 1994a,b; Klosiewski and Laing 1994), yet our results indicate that Lower

Cook Inlet is equally, if not, more important for marine birds during both summer and ~~~ .

21
Most of the differences between Lower Cook Inlet and Prince William Sound

during summer 1993 occurred in the offshore stratum. The estimated density of the

offshore stratum of Lower Cook Inlet (Table 6) was 45.7% higher than that calculated

for Prince William Sound (Table 17); whereas, the density in the shoreline stratum of

Lower Cook'iniet (Table 6) was only 2.7% greater than the estimated density of Prince

William Sound (Table 17). Species composition also differed between the two areas

(Tables 7 and 18). Although the most common birds observed in both areas during

summer were alcids, most of the alcids in Lower Cook Inlet were murres. In Prince

William Sound, the most abundant alcid was Brachyramphus murrelets. In Lower

Cook Inlet, the second most common species group was tubenoses (35%), but in

Prince William Sound, the second'most common group was gulls (31.4%).

We suggest that these differences in overall abundance of marine birds and in

the relative species composition between the two areas were due to differences in the

topography and oceanography of the two areas. Although the two areas were

sampled at approximately'the same time of year (Lower Cook Inlet, June; Prince

William Sound, July), it is possible that breeding cycles may have influenced the

estimates. We compared estimates from surveys done in June and July 1990 in

Prince William Sound and found that the estimate of total marine birds was 30%

higher in July. Thus, our estimates of marine bird abundance in Lower Cook Inlet are

conservative because Lower Cook Inlet was sampled in June, but Prince William

Sound was sampled in July.

The two areas differ in topography and overall structure. Prince William Sound

(Fig. 48), with its convoluted coastline of bays and fjords, has more shoreline (9.1 % of

total area) than Lower Cook Inlet (1.8% of total area, Table 1). Overall, the waters of

Lower Cook Inlet are shallower than Prince William Sound, and several of the bays on

the west side of the Inlet are very shallow, averaging <20 m in depth (Hayes et al.

1977). Southem Prince William Sound is protected by two large islands (Hinchinbrook

and Montague Islands). Oceanic water from the Gulf of Alaska enters the Sound

through one small entrance between the islands (Fig. 48); whereas, Lower Cook Inlet

is fairly open to the Gulf of Alaska (Fig. 4).

Lower Cook Inlet is considered "a well-mixed estuary" (Burbank 1977). The

large tidal ranges, seasonally variable amounts of fresh water runoff, and presence of

strong winds, which funnel down the long axis of the Inlet, create a fairly complex

circulation pattern within the Inlet. Oceanic water from the Alaska Coastal Current

(Fig. 4) enters the Inlet in its southeastern comer, causing upwelling northwest of the

Chugach Islands. This northward intrusion of seawater is deflected west near Anchor

Point by the strong, southward flow of turbid, low salinity water from the Upper Inlet,

creating a countercloCkwise gyre in the central part of the Inlet (Fig. 4). This large

gym generate,s two smaller gyres in the mouth of Kachemak Bay (Fig. 4). Lower .

Cook Inlet has'several large tide rips;' which act as' frontal zon'es, separating the more

dense seawater from the less dense southward flowing turbid waters.

,Marine bird distribution in Lower Cook Inlet appeared to be related to the

presence of both the seawater intrusion from the Gulf of Alaska and the tide rips.

She,arwaters, fulmars, and puffins were most abundant in the southeastem corner,

22

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where the oceanic water from the Alaska Coastal Current entered the Inlet. Sightings

of storm-petrels were most commc;m,along the tide ,rips, and Brachyramphus murrelet

abundance was highest near the small gyres in Kachemak Bay. Presumably, marine

birds inhabiting Lower Cook Inlet during summer are feeding and exploiting, areas near

frontal zones, sucH as the Alaska Coastal Current, increasing the probability that they

will find productiveIareas. , '

Winter Boat Survey.-During winter 1994, we only surveyed a portion of Lower

Cook Inlet; wherea~, we surveyed all ,of Prince William Sound. The abundance

estimate for LowerlCook Inlet (Table 4) was correspondingly lower than the Prince

William Sound esti(Tlate for March 1994 (320,470 ± 62,640 birds; Agler et al. 1994d).

The total density of marine birds in Prince William Sound (Table 18) was only slightly ,

higher than the de~sity in Lower Cook Inlet (Table 9), indicating a similar level of use,

by wintering marine birds. In both areas, the highest densities were estimated within

the shoreline stratJm, demonstrating the importance of this stratum for wintering

marine birds. I, ,

The most Icommon birds observed in both areas during winter were waterfowl,

but the species corhposiiion of this group differed between the two areas (Tables 10

and~O). In Low~r 'ICOOk Inlet, waterfowl consisted mostly of scoters (23.9% of total);

whereas, in Prince William Sound, goldeneyes were the most abundant waterfowl

(16.5% of total). 'In both areas, the second most common species group was alcids.

Murr~s made up,a higher proportion of the alcids in Lower Cook Inlet; whereas, in

Prince William Soupd, Brachyramphus murrelets were the most abundant alcid. In

both areas, gulls were the next most abundant species group. We suggest that the

differences in spedes composition were due to differences in habitat. Lower Cook

Inlet has more ope? water; whereas, Prince William Sound has more protected bays

and fjords. Smalle~ birds, such as goldeneyes and murrelets, prefer the more

protected habitats of Prince William Sound over the exposed waters of Lower Cook

Inlet., ,,", I

The densities of sea otters within Lower Cook Inlet were lower than those

estimated for Prince, William Sound during both winter and summer. This difference

was to be expected. Sea otters seemed to prefer the shoreline habitat in both areas,

and Prince William Sound has more shoreline than Lower Cook Inlet. Also, sea otters

have only recently {ecolonized Lower Cook Inlet (National Marine Fisheries Service

1988), and their populations appea.r to be increasing in the Inlet.

, , I Improvement of ttle Survey

, Increasedst~tification reduced the size of each stratum, reducing the sample

, size within each Stratum (Kraft et al. 1995). This reduced precision within the restratification design~. Thus, we simulated re-allocation of transects based on ,

abundance of marirte birds in each stratum, and this improved the precision of the

estimates. Re-allodation of samples resulted in a tie between the ranks of the original

, stratification (re-allobated) and the east-west stratification design with a shoreline, a

coastal, and a pelagic stratum (Fig. 10).

23
Kraft et al. (1995) found that although stratification generally increased

pn~cision,it usually increased cost. The highest abundances of marine birds were

observed in the eastern portion of Lower Cook Inlet, thus, in future surveys a higher

. proportion of the transects should be allocated to this stratum. This should actually

reduce costs, because transects on the western side of the Inlet are more difficult to

survey due to distance from support facilities. Thus, using the east-west stratification

design would allow us to reduce costs yet maintain precision. . .

We also examined allocation of samples based upon the species with the

hi~lhest variability (common murre), and we found that either original stratification

design (re-allocated or not re-allocated) had the best mean CV in that instance.

Overall, mean CV's were much higher using this method to allocate samples, and we

do not advise incorporating this technique into future surveys. We recommend

re..allocatirig samples in future surveys into the east-west stratification design to

reduce costs.

Survey Frequency .

We suggest two major reasons to conduct future surveys: (1) to examine the

effects of an environmental perturbation; and, (2) to determine long-term trends in

abundance. Klosiewski and Laing (1994) conducted Monte-Carlo simulations to

examine the lack of power associated with performing tests using the few data points

available within Prince William Sound to assess injury to marine birds from the Exxon

Va!/dez oil spill. When they generated data for a sampling regime that only included

two years of pre- and one year of post-perturbation data, estimated power was low,

re!lardless of the proportion of th~ population affected. This sampling regime gave a

20-40% chance of detecting a 50% decline for Brachyramphu5 murrelets, the species

group estimated with the highest precision. Estimated power increased substantially

with five years of pre- and one year of post-perturbation data (Klosiewski and Laing

1994). This sampling regime provided a 60-100% chance of detecting a 50% decline

for Brachyramphu5 murrelets. These results supported the importance of regular

monitoring. which would increase the likelihood of having a larger number of samples

from a disturbed area (Klosiewski and Laing 1994).

This is an important consideration for Lower Cook Inlet. Fifteen years

separated the only surveys (Arneson 1980) that have been conducted to estimate

marine bird densities of the area, and these surveys were not directly comparable

because of different methodologies. If an environmental perturbation were to occur in

Lower Cook Inlet today, we would have little power to detect declines for most

species, unless the decline was severe (>50%, Klosiewski and Laing 1994).

Klosiewski and Laing (1994) found that five years of pre-perturbation data would

substantially increase the chance of detecting a change in population abundance. If it·

is important to know effects of an environmental perturbation in Lower Cook Inlet, an

arE!a with a great deal of oil development and transport, we need more data on the

population abundance of marine birds of the area. Thus, we need to conduct more

surveys arid soon; otherwise, we will be unable to determine any injury to this

important resource within Alaska. .

24

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Statistical tests commonly use a small a level ~0.05) to minimize probability of

aType I error. THis reduces thepr'bbability of reporting a trend when none exists.

However, power, the ability to detect a trend when it does exist, is inversely related

to a. For exampl~, if we have a CV of 0.3 and .we increase the a level to <0.10, we

increase our power to detect a trend by 11-52%. If a population may be declining, the

benefits of increas~d power to detect a trend may outweigh the risks of lowering the . , I .

confidence level. rhus, we recommend using a higher a level such as z.0.1 O.

. Continued monitoring of Lower Cook Inlet would allow us to examine trends in

population abundahce over time. Klosiewski and Laing (1994) demonstrated that the

. populations of sorrle marine birds declined between 1972-73 and 1989-91. This may

also have occurred in Lower Cook Inlet. Regular monitoring of Lower Cook Inlet .

would provide the ~ata necessary to examine this hypothesis. From the results of our

power analysis, wJ recommend that surveys be conducted every 2·5 years. The

power analysis qleronstrated that survey frequency would markedly increase our

ability to detect trends in abundance. Models of seabird population growth predict

most species indre~se no more than 12% per year (Nur and Ainley 1992). Thus,

surveys should ocdur every other year over a 20-year period or every third year within

a 30-year period td achieve maximum power to detect an annual rate of change of .

1O%~ Models of s~abird population growth predict most species increase no more

than'12% per year (Nur and Ainley 1992).

CONCLUSIONS

. Surveying randomly-selected transects allowed us to estimate the abundance of

marine birds in LoWer Cook Inlet during summer 1993 and winter 1994. We found

that Lower Cook Inllet provides important habitat for large numbers of marine birds in

the Gulf of AlasKa during both summer and winter. This information is vital for

determining short- knd long-term changes in the abundance of marine birds in the

area. Similar data Ifrom Prince William Sound .has been used to determine changes in

abundance of marine birds over time (Klosiewski and Laing 1994).

Because sirrlilar methods were used in both studies, we made comparisons .

between Lower Cobk Inlet and Prince William Sound and developed hypotheses

regarding the undeHying ecology of the marine bird populations of coastal areas of the

Gulf of, Alaska. Aslthe Exxon Valdez oil spill demonstrated, oil spills are not limited to

one geographic loc~tion but move with the currents and wind. .

We recommend that surveys be conducted more frequently to increase the . , likelihood of detecting population changes in the event of an environmental

perturbation.. At the present time, we do not have enough data to detect population

changes due to an lenvironmental perturbation. We recommend surveying a portion of

Lower Cook Inlet (ie.--Kachemak Bay and the southeastem comer) every year for five

years to examine ahnual variability in the marine bird populations of the Inlet.

Abbreviated survey~, such as these, would also improve surveytechniques. We also

recommend condudting surveys of Lower Cook Inlet every 2·5 years to increase the

baseline data available. Increased monitoring of Lower Cook Inlet would permit

analysis of trends i~ population abundance. Marine bird populations in Prince William

25
Sound have declined since 1972-73 (Klosiewski and Laing 1994). This may have

occurred in Lower Cook Inlet but can not be detected due to insufficient data.

In conjunction with these surveys, we also recommend investigation into:

(1) comparisons between aerial and boat survey techniques; (2) differences between

surveys with short. randomly-selected transects and those with long, systematic lines;

(3) differences between the present method, in which we count all birds continuously

on each transect and the relatively new "snapshot" counts; (4) effects of tide and time

of day on bird distribution and abundance; (5) correlations of species distribution with

habitat; and (6) comparisons of Lower Cook Inlet with other regions in the state.

26

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I

LITERATURE CITED

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_, S. J. Kendall, P. E. Seiser, and ,D. B. Irons. 1994b. Population estimates of

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. I

appen Ices.

_, _, _, an~ _. 1994c. Field report: marine bird survey of Lower Cooklnlet,

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from 1990-94. Draft Rep., U.S. Fish and Wildlife Service, Anchorage, AK.

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. I .'

Agler, B. A:, S. J. !Kendall, P, E. Seiser, and J. R. Lindell. 1995. Estimates of marine

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I

Burbank, D.C. 1977. Circulation studies in Kachemak Bay and Lower Cook Inlet.

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studies of Kiachemak Bay and Lower Cook Inlet. Unpubl. Rep., Alaska Dept. of , I

Fish and Game, Anchorage, AK. XII vols.

Cochran, W. G.: lb77. Sampling t~chniqUes. John Wiley and Sons, Inc., New York

428 pp.

Conant, B., J. G. King, J. L. Trapp, and J. I. Hodges. 1988. Estimating populations of

ducks wintehng in Southeast Alaska. Pages 541-551 in M. W. Weller, ed.

Waterfowl in Winter. Univ. Minnesota Press, Minneapolis, MN.

, 27
• Crow, J, H. 1977. Food habits of shrimp in Kachemak Bay, Alaska. Vol. VI in L. L.

Trasky, L. B. Flagg, and D. C. Burbank, eds. Environmental studies of

Kachemak Bay and Lower Cook Inlet. Unpubl. Rep., Alaska Dept. of Fish and

GarDe, Anchorage, AK. XI! vols.

DeGange, A. R. and R. H. Day. 1991. Mortality of seabirds in the Japanese land·

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Dwyer, T. J., P. Isleib, D. A. Davenport, and'J. L. Haddock. 1976. Marine Bird

Populations in Prince William Sound, Alaska. Unpubl. Rep., U.S. Fish and

Wildlife SerVice, Anchorage, AK. 24 pp.

Erikson, D. 1977. Distribution, abundance, migration and breeding locations of

marine birds - Lower Cook Inlet, Alaska, 1976. Vol. VIII in L. L. Trasky, L. B.

Flagg, and D. C. Burbank, eds. Environmental studies of Kachemak Bay and

Lower Cook Inlet. Uhpubl. Rep., Alaska Dept. of Fish and Game, Anchorage,

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Gaston, A. J., B. L. Collins, and A. W. Diamond. 1987. The 'snapshot' count for

estimating densities of flying seabirds during boat transects: a cautionary

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Gerrodette; T. 1987. A power analysis for detecting trends. Ecology 68(5):1364-

1372. '

Gmen, R. H. 1979. Sampling design and statistical methods for environmental

biologists. John Wiley and Sons, Inc., New York. 257 pp.

Gould, P. J., and D. J. Forsell. 1989. Techniques for shipboard surveys of marine

birds. U.S. Dept. of Int., Fish and Wildlife Service, Washington D. C., Fish and.

Wildl. Tech. Rep. 25. 22 pp.

__, _, and C. J. Lensink. 1982. Pelagic distribution and abu,ndance of seabirds in

the Gulf of Alaska and eastem Bering Sea. U.S. Dept. of Int., Fish and Wildlife

Service, Biological Servo prog., OBS 82/48. 294 pp. .

Haney, J. C. 1985. Counting seabirds at sea from ships: comments on interstudy

comparisons and methodological standardization. Auk 102:897·898.

Hayes, M. 0., P.J. Brown,and J: Michel. 1977. Coastal morphology and

sedimentation· Lower Cook Inlet, Alaska. Vol II in L. L. Trasky, L. B. Flagg,

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Cook Inlet. Unpybl. Rep., Alaska Dept. of Fish and Game, Anchorage, AK. XII

vols..

28

I

I

I

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I

I

I

I

I

I

I

I

I

I

I

I

I

I
-;,------,--------r"----:----~.'-~--------- 11 ....

::1

,I

':

':1

ill'

"

I~

!i

'I

I

Ii

:1

:1

:ii

l

1'1

!,

~I I ,

!:

!,I

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l

'i'

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.oj

Haynes, E. B. 1977. Summary status on the distribution of king crab and Pandalid

shrimp larvae, Kachemak Bay - Lower Cook Inlet, Alaska, 1976. vol. IV. in

. L. L. TraskX, L. B. Flagg, and D. C. Burbank, eds: Environmental studies of

Kachemak Bay and Lower Cook Inlet. Unpubl. Rep., Alaska Dept. of Fish and I

Game, AnCrOrage, AK. XII vols. ,

Horrer, P. L.196l Methods and devices for measuring currents. Pages 80-89 in

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D.C.

Irons, D. B., D. R. Nysewander, and J: L. Trapp. 1988a. Prince William Sound sea

,otter distribution , in relation to population growth and habitat type. Unpubl.

- Rep., U.S. Itish and Wildlife Service, Anchorage, AK. 31pp.

, ,and. I 1988b. Prince William Sound waterbird distribution in relation to

- habitat type) Unpubl. Rep., U.S. Fish Wildlife Service, Anchorage, AK. 26 pp.

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227-239 in ~. C. Bartonek and D. N. Nettleship, eds. Conservation of marine

birds of northern North America. U.S. Fish and Wildlife Service, Washington,

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, ,

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29

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Pennington, M., and J. H. V0lstad. 1994. Assessing the effect of intra-haul

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Piatt, J. F. 1993. Monitoring seabird populations in areas of oil and gas development

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assemblages at the mouth of a tidally-mixed estuary (Cook Inlet, Alaska).

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Pojar, T. M.,.D. C. Bowden, and R. B. Gill. 1995. Aerial counting experiments to

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Schneider, K. B. 1976. Assessment of the distribution and abundance of sea otters

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Spear, L., N. Nur, and D. G. Ainley. 1992. Estimating absolute densities of flying

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, Strategic Mapping, Inc. 1992. Atlas GIS: Using Atlas GIS desktop geographic

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Tasker, M.L., P. H. Jones, T. Dixon, and B. F. Blake. 1984. Counting seabirds at

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standardized approach. Auk 101 :567-577.

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Game, Anchorage, AK. XU vols.

Udl~vitz, M. S., J.·L. Bodkin, and D. P. Costa. 1995. Detection of sea otters in boatbased sUiveys of Prince William Sound, Alaska. Mar. Mamm. Sci. 11(1):59-71.

van Franeker, J. A. 1994. A comparison of methods for counting seabirds at sea in

the southern ocean. J.Field Omithol. 65(1):96-108.

30

I

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I

I

I

I

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I

I

I
"!j

'II

!lll

:1 .

!II Wagner, D. G·,iR. S. Murphy, and C. E. Behlke. 1969. A program for Cook Inlet.

:; . . Alaska, for Ithe collection, storage and analysis of baseline environmental data.

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';1 284 pp.

, .

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31

- - --- _r~ _ _~ _-~ _~_

- - "'-=-'-''- --=-..;._....,- ..:~

- - - - - - -

Table 1. Area (km2) of strata used on boat surveys of Lower Cook Inlet during summer 1993 and winter 1994 to

estimate population abundance of marine birds. Includes area of strata from a similar survey of,Prince William

Sound during July 1993 (Agler et al. 1994a).- - ,

Prince William Sound , Lower Cook Inlet

Summer- Winter -

% of No. of % of- No. of

Stratum Area Total Transects Area Total Transects

Shoreline 244.11 1.8 86 68.21 1.9 37

Coastal" 3,563.00 25.8 112 1,220.89 33.3 61

Pelagic" 9,983.88 72.4 213 2,371.83 64.8 85

Offshore" 13,546.88 98.2 325 3,592.72 98.1 147

Totalb 13,790.99 100.0 411 3,660.93 100.0 184

Area.

820.74

8,161.11

8,981.85

% of

Total

9.1

90.9

100.0

" The coastal and pelagic strata of Lower Cook Inlet and Prince William Sound were defined differently. To

prevent confusion in this comparison, we combined the two strata as an offshore stratum. During the winter 1994

survey, Kachemak Bay was used as the coastal stratum.

b Total only includes the area for the shoreline and combined offshore strata, so the column labeled "area" will

not add vertically.

...

32
Table 2. Species groups used to estimate population size of marine birds during

summer 1993 and winter 1994 boat surveys of Lower Cook Inlet.

Group / Common Name

Loons

Red-.throated loon

Pacific loon

Common loon .

Yellow·billed loon

Unidentified loon

Grebes

Horned grebe

Red-necked grebe

Unidentified grebe

Tubenoses

Northern fulmar

SooW shearwater

Short-tailed shearwater

Unidentified shearwater

Unidentified procellariid

Fork-tailed storm-petrel

Unidentified storm-petrel

Shearwaters and fulmars

Northern fulmar

Sooty shearwater

Short-tailed shearwater

Unidentified shearwater

Unidentified procellariid

Shearwaters

Sooty shearwater

Short-tailed shearwater

Unidentified shearwater

Storm-petrels

Fork-tailed storm-petrel

Unidentified storm-petrel

33

Species Name

Gavia stel/ata

G. pacifica

G. immer

G. adamsii

G. sp.

Podiceps auritus

P. grisegena

P. sp.

Fulmarus glacialis

Puffinus griseus

P. tenuirostris

P. sp.

P. sp. or F. sp.

Oceanodroma furcata

Oceanodroma sp.

Fulmarus glacialis

Puffinus griseus

P. tenuirostris

P. sp.

P. sp. or F. sp.

. P. griseus

P. tenuirostris.

P. sp.

Oceanodroma furcata

Oceanodroma sp.

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Table2 (continued). . . . I , I

Group/ Common Name I

Cormorants.I

Double-crested cormorant

.I

.Pelagic cormorant . I

Red-faced cormorant

Unidentified cormorant

Waterfowl

Brant

Mallard

Northern pintail . I

Northern shoveler

Gadwall

Unidentified dabbling duck

Greater scaup

Unidentified!scaup

Common eider

King eider

I

Steller's eider

Harlequin d~ck

OldsquawI

Black scote~1

Surf seater

White-wingeCl scoter

Unidentified Iscoter

Common goldeneye , Barrow's goldeneye

Unidentified goldeneye

Bufflehead·

Common merganser

Red-breastetl merganser

Unidentifled Imerganser

Unidentified Idivlng/sea duck

Unidentified duck.

Scaup

Greater scaup

Unidentified ~caup

34

Species Name

Phalacrocorax auritus

P. pelagicus

P. urile

P. sp.

Branta bemicla

Anas platyrhynchos

A. acuta

A. clypeata

A. strepera

A. sp.

Aythya marila

A. sp.

Somateria mollissima

S. spectabilis.

Polysticta stelleri

Histrionicus histrionicus

Clangula hyemalis

Melaniffa nigra

M. perspicillata

M. fusca

M. sp.

Bucephala clangula

B. islandica

B. is/andica or clangula

B. albeola

Mergus merganser

M. serrator

Mergus sp.

Aythya marila

A. marila or affinis

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Table2 (continued).

•.I

: I

Group/ Common Name I

Gulls Bonaparte,J gull

Mew gull

Herring gull

Glaucous-winged gull

Black-Ieggeb kittiwake

Unidentified gull

Terns

Arctic tern

Aleutian tern

Unidentified tern

Alcids, Common murre .Thick-billed fnurre

Unidentified Imurre

Pigeon guillemot

.

Marbled mutrelet

Kittlitz's mu~relet

Brachyramphus murrelet , Parakeet auklet

Tufted pUffih

Horned puffi'n

Unidentified puffin

Unidentified alcid

Murres

,.

Common mwrre

ThiCk-bill8d murre

Unidentified murre

Murrelets

Marbled murrelet

Kittlitz's murtelet , Brachyramphus murrelet

36

Species Name

Larus philadelphia

L. canus

L. argentatus

L. glaucescens

Rissa tridactyla

L. or R. sp.

Sterna paradisaea

S. aleutica

S. sp.

Uria aalge'

U.lomvia

U. sp.

Cepphus columba

Brachyramphus marmoratus

B. brevirostris

B. sp,

Cyclorrhynchus psittacula

Fratercula cirrhata

F. corniculata

F. sp.

Family Alcidae

Uria aalge

U.lomvia

U. sp.

Brachyramphus marmoratus

B. brevirostris

B. sp.
Table

2 (continued).

Gmup/ Common Name

Puffins.

Tufted puffin

Homed puffin

Unideritified puffin

37

SpeCies Name

Fratercula cirrhata

F. corniculata

F. sp.

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- - -==--:- =. ....: - "" ..:.=.-==, ::..::- ~=,

- - -- - - - - .:::,..•-r-. ..::... ,:,__ .:=-== _,=-....:... ........:=. ,=- '::::.'" =, ~-.=-:_ .-:~_==- :.= ":"='=--:_-~O-' ',.-":' "'==_.. '

---------

Table 3. List of re-stratifications examined to determine how future surveys be re-stratified to improve precision ofestimates in surveys of marine birds and sea otters in Lower Cook Inlet, Alaska.

Original'

Distance from Colonies (km)b

Strata

All Lower Cook Inlel

Orlgk,a..

3 nm coastal

By % . 5 nm coastal No coastal 5 10 15

Easl-Wesl"

North·Soulh' No Coa.staL:-C.oaslal

Shoreline

Coastal

Pelagic

Colonies

From

Colonies

Pelagic

North

Shoreline

Offshore

South

Offshore

Kamishak Bay

Shoreline

Offshore

<0.1 nm <0.1 nm ::.0.1 nm

>0.1 nm >0.1 nm >0.1 nm

<3 nm =::3 nm =::5 nm

>3nm >3 nm >5 nm

=::0.1 nm

>0.1 nm

::.5 km

>5 km

::.10 km

>10 km

::.15 km

>15 km

.~.o: 1 nm

>1 nm

>1 nm

20.1 nm

>1 nm

38
1

Table 3 (continued).

Originalll

3 nm coastal ._Distance lrom Colonies (km)' East,Wesl" .

Sirata Original

'i"- ,~'''.~

By% 5 nm coastal No coastal 5 10 15 North-South' No Coastal Coastal

..!.

Kachemak Bay

., . Shoreline 

:0.0.1 nm ,

Offshore >1 nm

Easl

Shor~lin; - . - - ~-

:0.0.1 nm ;;;.0.1 nm

Offshore >1 nm :>lnm

Coastal >0.1 nm

.=:,3 nm

Wesl

Shoreline :5:.0.1 nm <0.1 nm

·Oltshore >lnm . :> 1 nrn

Coastal >0.1 nm

<3 nm

a The original stratification included a shoreline, a coastal, and a pelagic slratum.. Transecls were"re-allocated among these strata by marine bird

abundance (by % ot birds).. We also examined re-stratilication wilh a larger (5 nm) coastal stratum and without the coastal stratum.

, We. re-stratilied by creating a slratum 01 varying distances arou·nd colonies 01 >500 birds.

, North-south denoles re-stratilication based on dividing the Inlet into northern and soulhern strata at Anchor Point and placing Kamishak and

Kachemak Bays into separate strala.

• We divided the Inlel into east and west slrata with a 3 nm coastal stratum and without this stratum.

39

._"""- ---~~-.~-

- - - - - - - - - - - - - - - - - - -
"

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Table 4. Populatili>n estimates (N ± 95% CI) for species groups of marine birds

observed d~ring small boat surveys of Lower Cook Inlet in summer 1993 and a

combined sfnall boat and shipboard survey in eastem Lower Cook Inlet in

winter 19941

. .

I !

Summer 1993 Winter 1994

Species Group N CI N CI

Loons 2.563 1,492 304 193

Grebes 0 0 648 406

Tubenoses 279.375 85.022 1,056 1.005

Shearwaters and fulmars 165.507 57,488 1,056 1,005

Shearwaters 105,805 43,421 0 0

Storm·petrels 113,868 60,099 0 0

Cormorants 6,674 2,497 6,294 1,850

Waterfowl 66,035 71,789 56,607 19,985

Scaup 1,556 1,563 91 149

Eiders 2,844 3,966 5,822 5,435

Harlequin duck 3,n4 2,025 1,940 955

Oldsquaw 248 466 11,058 9,556

Scoters 49,077 70,529 29,408 11,281

Goldeneyes 3 7 3,638 2,224

Mergansers 2,103 2,065 1,403 922

Shorebirds 107 87 2 4

Jaegers 511 426 0 0

GuliS 128,946 40,896 16,089 4,752

Tems 6,394 3,885 0 0

Alcids 304,318 139,532 40,271 12,810 -

Murres I 169,192 135,741 25,406 9,603

I

Guillemots •. 1

8,791 3,081 2,914 1,398

Murrelets' 58,227 16,058 11,627 7,410

Puffins I 66,899 16,409 0 0

Total marine birds I 798,042 195,555 122,946 25,804

• Marbled and Kittlitz's murrelets only,

40
Table 5. Population estimates (N.:!: 95% Cll, by stralum, for species groups ot marine birds observed on a small boat survey of Lower Cook

Inlet during summer 1993.

Shoreline Coastal Pelagic Offshore'

Species Group N CI N CI -N CI- N CI

Loons 310 149 857 500 1,396 1,398 2,253 1,485 ,

Grebes 0 0 0 0 0 0 0 0

Tubenoses 0 0 17,465 15,218 261,910 83,649 279.375 85,022

Shearwaters and fulmars 0 0 17,132 15,221 148,375 55,436 165,507 57,488

Shearwaters 0 0 13,848 13,681 91,957 ~1,209 105,805 43,421

Storm-pelrels 0 0 333 482 113,534 60,097 113,868 60,099

Cormorants 2,201 1,297 3,522 1,887 952 997 4,473 2,134

Walerfowl 9,007 3,069 51.062 71,433 5,965 6,455 57,027 71,724

Scaup --- -- 747 1,319 619 752 190 373 _809 839 _-

Eiders 607 488 2,237 3,936 0 0 2,237 3.936

Herlequin duck 2,965 1,684 809 1,124 0 0 809 1,124

Oldsquaw 10 15 238 466 0 0 238 466

Scoters 2,568 1.314 46.446 70,517 63 124 46,509 70,517

Goldeneyes 3 7 0 0 0 0 0 0

Mergansers 437 398 143 208 1,523 2,015 1,666 2,026

Shorebirds 107 87 0 0 0 0_ 0 0

Jaegers 3 7 0 0 508 426 508 426

Gulls 21,883 12,390 74.380 38,289 32,683 7,272 107,063 38,974

Terns 17 24 3,141 3,317 3,237 2,023 6,377 3,885

Alcids 3,208 1,281 104.503 135,219 196,607 34,399 301,110 139,526

Murres 540 804 83,421 134,650 85,230 17,158 168.652 135,739

Guillemols 1,477 693 4,521 2,014 2,792 2,226 7,313 3.002

Murrelels' 447 345 11,707 7,154 46,074 14,373 57,780 16,055

Pullins 740 665 4.854 2,688 61,305 16,174 66,159 16.396

Total marine birds 37,333 13,586 254,975 168,684 505,733 97,995 760,708 195.083

, The coastal and pelagic strata were combined 10 form (he offshore stratum.

, Marbled and Kitllilz's murrelets only.

41

-....,.- ----_.._---,- ------ - - _. _. --', -- .--' -_ .. -- --- .- -- ..._- ._- .__.- - ----'---'

- - - - - - - - - - - - - - - -- - - -
·Ii

I' II!

;:1j,

ill Table 6, Densities (birds/km2

) of species groups of marine birds obseNed on a small

boat sUNeyi of Lower Cook Inlet during summer 1993 and listed by stratum.

F

!'I Species Group I Total Shoreline Coastal Pelagic Offshore'

II Loons 0.2 1.3 0.2 0.1 0.2 iii

p Grebes 0.0 0.0 0.0 0.0 0.0

Tubenoses 20.3 0.0 4.9 26.2 20.6 ':1 Shearwaters and fulmars 12.0 0.0 4.8 14.9 12.2

I Shearwaters 7.7 0.0 3.9 9.2 7.8

:1 ,.; Storm-petrels 8.3 0.0 0.1 11.4 8.4

:j. Cormorants 0.5 9.0 1.0 0.1 0.3 "II

I'

'I Waterfowl 4.8 36.9 14.3 0.6 4.2

::1 Scaup 0.1 3.1 0.2 <0.1 0.1

,

I' Eiders 0.2 2.5 0.6 0.0 0.2 !, -

" Harlequin duck 0.3 ' 12.1 0.2 0.0 0.1

1:1 Oldsquaw <0.1 <0.1 0.1 0.0 <0.1

I, Scoters 3.6 10.5 13.0 <0.1. 3.4

~I Goldeneyes <0.1 <0.1 0.0 0.0 0.0

Mergansers 0.2 1.8 <0.1 0.2 0.1

:1 Shorebirds <0.1 0.4, 0.0 0.0 0.0

Jaegers <0.1 <0.1 0.0 0.1 <0.1 II Gulls 9.4 89.6 20.9 3.3 7.9 I

:i

I. Terns 0.5 0.1 0.9 0.3 0.5

I. Alcids 22.2 13.1 29.3 19.7 22.2 ,

Murres 12.3 2.2 23.4 8.5 12.5 ,I,. Guillemots 0.6 6.1 1.3 0.3 0.5 !,

Murrelets· 4.2 1.8 3.3 4.6 4.3 I'. Puffins 4.9 3.0 1.4 6.1 4.9

: Total marine birdS 57.9 152.9 71.6 50.7 56.2

'I I ' , I,

oj

, a The coastal and pelagic strata were combined to form the offshore stratum. "

• Marbled and Kittlitz's murrelets only. , . "

I'

'~I

42

•

'.,I,

"

- .. -~---~-~ - _~_-~·.if~ __ ,- _: •.:.: :: ".---==- .

- - - - -

'''::;:.- "=. ="::..

- -

Table 8. Population estimates (N ± 95% CI), by stratum, for species groups of marine birds observed on a combined

small boat and shipboard survey of eastern Lower Cook Inlet during winter 1994.

Shoreline Bay Pelagic Ollshore'

Species Group N CI N CI N CI N CI

Loons 95 39 133 158 75 104 208 189 ....-. . .' Grebes - 248 111 400 391 0 0 400 391

Tubenoses 0 0 0 0 1.056 1.005 1.056 1,005

Shearwaters & fulmars 0 0 0 0 1,056 1,005 1,056 1,005

Shearwaters 0 0 0 0 0 0 0 0

Storm-petrels 0 0 0 0 0 0 0 0

Cormorants 727 331 3,531 1,398 2,036 1,165 5,566 1,820

Waterfowl 9,038 2,480 30,943 13,560 16,626 14,470 47,569 19,831

Scaup 91 149 0 0 0 0 0 0

Eiders 220 353 3,264 3,016 2,337 4,507 5,602 5,423

Harlequin duck 1,374 563 566 772 0 0 566 772

Oldsquaw 91 48 4,030 2,570 6,937 9,204 10,967 9,556

Scoters 3,332 1,507 21,251 10,033 4,826 4,933 26,076 11,180

Goldeneyes 2,446 1,147 966 1,854 226 443 1,192 1,906

Mergansers 799 542 566 742 38 74 604 746

Shorebirds 2 4 0 0 0 0 0 0

Gulls 2,173 935 8,827 4,422 5,090 1,465 13,916 4,659

Alcids 719 440 31,410 12,581 8,143 2,371 39,553 12,802

Murres 530 413 19,485 9,415 5,391 1,845 24,876 9,595

Guillemots 42 23 1,665 1,034 1,206 940 2,872 1,397

Murrelets' 144 65 10,126 7,388 1,357 570 11,483 7,410

Total marine birds 14,611 2,792 75,310 21,069 33,025 14,634 108,335 25,652

, The coastal and pelagic slrala were combined to form Ihe ollshore stratum.

, Marbled and Killlitz's murrelels only, •

44

i!.

'I:;.

"..",

•

'I

iii

'.

II<,il .'Ii"

III'.,.

::1, i

:1

i!

III:.

::.'

!,

I,.

:i

l

;.

!:.

·;1

:'. "

Ii,'

'il

Ii"
-I I J

., ,I

f 

I i

,

I

Table 11 .• Comparison of population estimates (N ± 95% CI) of marine birds observed ,I I during shipboard surveys of the pelagic stratum of eastern Lower Cook Inlet I

during winter 1994. Lines: denotes population estimates determined from nine I lines of varying lengths surveyed completely by a large vessel, and segments

denotes population estimates calculated from a subset consisting of 85 I

randomly-chosen 2~nm segments similar to the transects used in the summer

1993 survey. I

Lines Segments

Species Group N CI N CI I

Loons ' 132 123 75 104

Tubenoses 564 1,126 1,056 1,005 I , Shearwaters and fulmars 564 1,126 1,056 1.005 I Cormorai;lts 1,937 1,782 2,036 1,165

Waterfowl 10,739 16,938 16,626 14,470 I I

Eiders 1,354 2,573 2,337 4,507

Oldsqua'lil 3,329 8,237 6,937 9,204 I

Scoters 4;363 6,417 4,826 4,933

Goldeneyes 320 798 226 443 I

Mergansers 38 60 38 74

Gulls 4,119 1,118 5,090 1,465

I , I

Alcids 7,993 2,473' 8,143 2,371

I Murres 5,417 1,988 5,391 1,845 I ' I

i Guillemots ' 922 787 1,206 940 I I Murrelets~ 1,505 541 1,357 570

Total manne birds

,

25,484 17,727 33,025 14,634

I ,

a Marble'd and Kittlitz's murrelets only. ,I

I

I

I

I

I

I I

47 I

I I

I

i

I • I

i
Table 12. Percentage of times CV's of population estimates from short (2 ni'n)

segmentsdalculated during a Monte Carlo simulation were lower than CV's

from data dollected along nine lines of varying lengths. We simulated less

effort «Eff9rt) by calculating percentages using 50% of the short segments,

then we used 100% of the segments to simulate equal effort and re-calculated

the percent~ges,

,. I

48

54

100

100

100

100

100

100

100

100

36

59

100

100

96

15

100

<Effort Equal Effort

• MarbledJnd Kittlitz's murrelets only.

Species Group I

Loons 0

Tubenoses 99

Shearwaters and fulmars 99

Cormorants 89

Waterfowl 98

Eiders 0

Oldsquaw 100

Scoters 92

Goldeneyes 100

Mergansers 0

Gulls 0

Alcids 8

Murres 33

Guillemots 27

Murrelets' 0

Total marine birds, 100

-:1I;

!~I "j

!1

!I

,;1

Ii

::.~ Ii

I'I'.I

,'1
1

4

IIIIIIIIIIIIIIIIII
~~'-~'-", .. .. _~-. ---~ r .---0 .. _

- - "",'-:::I: -_ ~._:.;:~_.

- -

":;.: ..- - ='==" -~ .. <.

- -- - - - -

-.

.Table 13. Number and density of marine birds and mammals counted during an aerial.survey of the shoreline of

western Lower Cook Inlet during winter 1994. Combined shoreline included the western shoreline and

Kachemak Bay. Inside 0.1 nm (200 m) corresponds to the area surveyed by a small boat winter survey, and the

0.2 nm (400 m) zone was similar to the area surveyed previously by air (Erikson 1977, Arneson 1980).

Western Shoreline. Combined Shoreline

Inside 0, 1 nm Total 0.2 nm' " Inside 0.1 nin Tolal0.2 nm

Species Count Density Count Densily Count Density Count .Density

Marine Birds

Loons 1 <0.1 1 <0.1 11 <0.1 34 <0.1

Grebes 0 0.0 0 0.0 0 0.0 7 <0.1

Cormorants 13 0.1 25 0.1 99 0.5 237 0.7

Waterfowl 1,236 9.6 4,490 16.0 4,888 26.5 11,015 30.8

Green-winged teal 0 0.0 0 0.0 4 <0.1 4 <0.1

Mallard 0 0.0 40 0.2 71 0.4 261 0.7

Scaup 29 0.2 136 0.6 279 1.5 386 1.1

Common eider 4 <0.1 38 0.2 55 0.3 103 0.3

Steller's eider 200 1.6 1,363 5.5 631 3.4 1,805 5.0 • Harlequin duck 176 1.4 273 1.1 327 1.8 534 1.5

Oldsquaw 436 3.5 1,155 4.6 ·511 2.8 1,368 3.8

Black scoter 213 1.7 1,177 4.7 627 3.4 2,054 5.7

Surf seoter 0 0.0 12 0.1 480 2.6 689 1.9

White-winged scoter 2 <0.1 ·16 0.1 112 0.6 399 1.1

Unidentified scoter 0 0.0 6 <0.1 0 0.0 6 <0.1

SCoters 215 1.7 1,211 4.9 1,219 6.6 3,148 8.8

Goldeneyes 76 0.6 87 0.4 478 2.6 1,215 3.4

Bufflehead 0 0.0 0 0.0 12 <0.1 108 0.3

Mergansers 100 0.8 187 0.8 1,301 7.1 . 2,083 5.8

Shorebirds 200 1.6 234 0.9 230 1.3 464 1.3 - Gulls 31 0.3 49 0.2 848 4.6 1,301 3.6

Herring gull 0 0.0 11 <0.1 1 <0.1 37 0.1

49

., ,..
Table 13 (continued).

Western Shoreline Combined Shoreline

Inside 0.1 nm Total 0.2 nm Inside 0.1 nm Total 0.2 nm

Species Count Density Count Density Count Density Count Density

Glaucous-winged gull 0 0.0 0 0.0 10 <0.1 10 <0.1

Glaucous gull 4 <0.1 4 <0.1 4 <0.1 12 <0.1

Unidentified gull 27 0.2 34 0.1 833 4.5 1,241 3.6

Alcids 0 0.0 2 <0.1 2,421 13.1 7,312 20.4

Murres 0 0.0 2 <0.1 2,421 13.1 7,306 20.4

Murrelets' 0 0.0 0 0.0 0 0.0 6 <0.1

Bald eagle 5 <0.1 6 <0.1 81 0.4 102 0.3

- Common raven 1 . <0.1 1· <0.1 _. - 1 <0.1 --1 <0.1

Total marine birds· 1,486 11.8 4,807 19.3 8,578 46.5 20,852 57.5

Marine Mammals

Beluga whale 2 <0.1 4 <0.1 2 <0.1 4 <0.1

Sea otter 68 0.5 186 0.8 140 0.8 469 1.3

Steller sea lion 0 0.0 0 0.0 17 <0.1 17 <0.1

Harbor seal 27 0.2 64 0.3 33 0.2 76 0.2

• Marbled and Kittlitz'smurreh~ts only.

b Bald eagles and common ravens were not included in total marine birds, so this column will not add vertically.

50

-------------------_~,Ol,.:
:'1

!!

';. Table 14. Number and density of marine birds and mammals counted during an aerial

" shoreline $urvey , of Kachemak Bay, Alaska during winter 1994 and population

estimates ~N) from a winter small boat survey in the 0.1 km (200 m) zone.

"I Total 0.2 nm (400 m) includes all area surveyed by air. ,

"

I ,.

,i. Aerial Survey Boat Survey

Inside 0.1 nm Total 0.2 nm 0.1 nm

"

, Species Count Density Count Density N Density '."1

Marine Birds

Loons 1-0 0.2 33 0.3 81 1.4 ". "

Grebes 0 0.0 7 <0.1 218 3.7

Cormorants 86 1.5 212 2.0 377 6.4

Waterfowl 3,652 62.2 6.525 60.0 7,661 130.0 I Green-winged teal 4 <0.1 4 <0.1 0 0.0

" Mallard 71 1.2 221 2.0 145 2.5

Iii

Scaup 250 4.3 250 2.3 85 1.4

Common eider - 51 0.9 65 0.6 2 <0.1 i' Steller's eider 431 7.3 442 4.1 192 3.3 i'. Harlequin duck 151 2.6 261 2.4 1.217 20.6

Oldsquaw 75 1.3 213 2.0 81 1.4 II Black seater 414 7.1 877 8.1 345 5.9 ,:. Surf seater 480 8.2 677 6.2 1,112 18.9

I: Wh,ite-wingedscoter 110 1.9 -383 3.5 781 13.2

r Seaters 1,004 17.1 1,937 17.8 2,533 42.9 I. Goldeneyes 402 6.9 1,128 10.4 '2,280 38.6 II Bufflehead 12 0.2 108 1.0 256 4.3

Mergansers 1.201 20.5 1.896 17.4 735 12.5 i. Shorebirds 30 ' 0.5 230 2.1 0 0.0

Gulls 817 13.9 1,252 11.5 930 15.8

:.• Herring gull 1 <0.1 26 0.2 46 0.8

Glaucous-winged gUll 10 0.2 10 <0.1 708 12.0 II Glaucous gull 0 0.0 8 <0.1 0 0.0 ~I Unidentified guO' 806 13.7 1,207 11.1 12 0.2 "

:;

Alcids 2,421 41.3 7,310 67.2 662 11.2 ;'. Murres 2,421 41.3 7,304 67.2 488 8.3 " ,Murrelets' 0 0.0 6 <0.1 135 2.3 :1 Bald eagle 76 1.3 96 0.9 180 3.1 ,,1 Common raven 0 0.0 0, 0.0 4 <0.1

Total marine birds· 7,092 120.9 15.775 145.1 10,143 171.9 ,

1'.

i.•

I' 51 "

'"'.

"I'
52

,

a Marbled and Kittlitz's murrelets only.

, b Bald eagle and common rdven were not included in total marine birds, so this

column will not add vertically.

, Aerial Survey

1

I

1

I'

I

1

1

I

I

1

I

I

I

I

I

I

I

I

I

0.1 nm

151 2.6

4 <0.1"

26 0.4

N Density

Boat Survey

2.6

0.2

0.1

283

17

12

1.2

0.3

0.1

72

17

6.

Inside 0;1 nm Total 0.2 nm

Species , Count Density Count Density

, Marine Mammals

Sea otter,

Steller sea lion

Harbor seal

Table 14 (continued).
~~-_ ..~-"~-~--~ --".~- ~" ~-.

• - - - - - - - - - - ,;::-== _.::--=- .=.-

- - -= 

Table 15. Densities of marine birds from an aerial survey of the Kachemak Bay and western shorelines of Lower Cook

. Inlet during winter 1994. Shoreline sections follow Arneson (1980): (3) Anchor Point to Homer Spit tip; (4) Homer

Spit tip to Peterson Bay; (5) Chinapoot Bay to Point Bede; (8) Tuxedni Bay; (9) Shoreline between Tuxedni Bay

and Chinitna Bay; (10) Chinitna Bay; (11) Iniskin Peninsula; (12) Oil Bay, Iniskin Bay and Iliamna Bay; (13) South

Head to Chenik Head, includes Ursus Bay and Bruin Bay; (14) Amakadedulia Cove, McNeil Cove, Akumwarvik

Bay; and (15) Shoreline between Akumwarvik Bay and Cape Douglas. , '.. Kiictiemal( Bay Sl10reline Western Shoreline

Species 3 4 5 8 9 10 11 12 13 14 15

Common loon 0.0 <0.1 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Unidentified loon 0.2 0.1 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 <0.1

Loons 0.2 0.2 0.4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 <0.1

Red-necked grebe 0.0 <0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Grebes 0.0 <0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Cormorants· 0.9 2.5 1.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 .

Waterfowl 28.3, 49.5 70.5 6.0 3.2 20.3 47.1 27.5 20.4 4.9 15.0

Green-winged leal 0.0 0.0 <0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Mallard 0.0 . 0.8 3.1 1.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Dabbling ducks 0.0 0.8 3.2 1.2 . 0.0 0.0 0.0 0.0 0,0 0.0 0.0

Scaup· 0.0 0,0 4.1 0.0 0.0 <0.1 0.0 2,3 0.0 0,0 0.7

Goldeneyes· 0.0 10.6 11.3 2.4 . 0.0 0.0 0.0 0.0 0.0 0.0 <0.1

Bufflehead 0.0 1.8 0.6 0.0 0.0 0.0 0.0 0.0 0.0 0,0 0.0

Diving ducks 0.0 12.4 16.0 2.4 0.0 <0.1 0.0 2.3 0.0 0.0 0,8

Common eider 3.5 0.0 0.7 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.7

Steller's eider 3.2 0.0 6.9 0.0 0.0 0.0 0,0 9.9 16.4 0,0 0.0

Eiders 6.7 0.0 7.5 0.0 0.0' 0.0 0.0 10.0 16.4 . 0.0 0.7

Harlequin duck 0.0 0.0 4.3 0.0 0.0 0.4 1.2 1.1 0.2 0.0 ' 3.9

Oldsquaw 6.2 1.2 2.0 1.1 0.0 13.6 0.0 9.1 1.4 4.8 5.0

Black seater 15.4 0.9 12.0 0.0 2.8 2.9 45.9 4.2 1.9 0.0 4.0

Surf scaler 0.0 3.2 9.0 0.0 0.0 0.0 0.0 0.0 0,0 0,0 0.3

While-winged seater 0.0 3.9 3.6 0.2 0.0 0.0 0,0 0.0 0.0 0.0 0.2

- 53
Table 15 (continued).

Kachemak Bay Shoreline Western Shoreline

Species 3 4 5 6 9 10 11 12 13 14 15

Unidentified scoter 0.0 0.0 0.0 0.0 0.0 0.0 0.0 . 0.0 0.0 0.0 0.1

Scoters 15.4 7.9 24.6 0.2 2.6 2.9 45.9 4.2 1.9 0.0 4.5

Sea ducks 28.3 9.2 36.4 1.3 2.6 16.9 47.1 24.4 19.9 4.6 14.2

Red-breasted merganser 0.0 27.2 12.9 1.1 0.2 3.4 0.0 0.6 0.5 0.1 <0.1

Mergansers 0.0 27.2 12.9 1.1 0.2 3.4 0.0 0.6 0.5 0.1 <0.1

Bald eagle 7.5 0.3 0.6 <0.1 0.0 0.0 0.2 <0.1 0.0 <0.1 <0.1

Shorebirds· 0.0 5.7 0.0 0.0 0.0 6.9 0.0 0.0 0.0 0.0 0.7

Mew gull 0.0 <0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Herring gull 0.0 0.6 0.0 <0.1 0.0 0.3 0.0 <0.1 0.0 0.0 0.0

Glaucous-winged gull - - - - -

0.0 0.0 0.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Glaucous gull. 0.2 0.1 <0.1 <0.1 0.0 0.0 0.0 <0.1 <0.1 0.0 <0.1

Unidenlified gull 10.0 12.7 10.1 0.0 0.0 <0.1 0.0 0.7 0.0 0.0 <0.1

Gulls 10.1 13.5 10.3 0.1 0.0 0.4 0.0 0.7 <0.1 0.0 <0.1

Alcids 0.0 164.1 10.4 <0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Murres· 0.0 164.0 10.3 <0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Murrelets' 0.0 <0.1 <0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Northwest crow 0.0 1.2 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0;0

Common raven 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 <0.1

Total marine birds· 46.9 236.9 95.0 6.2 3.0 .29.7 47.3 26.2 20.4 5.0 16.3

• Area surveyed was less than Arneson (1960) original sections.

• Within these groups, total birds were not identified to species.

, Marbled and Kittlitz's murrelets only.

• Bald eagles, northwest crows, and common ravens were not included in total marine birds, thus this column will not add vertically.

54

•

- - - - - - - - - - - .- - - - - - - -
- - _~iiii ~_ ~ciilll

iifC_=:~iii ~c_' _'"~_" ~_=" ..r "_ _:... .~. -= . ~~- '';'--: =- -:= ,=

- - --

Table 16. Correction factors (CF) incorporating detection errors in counts of marine birds from aerial surveys in Lower

Cook Inlet during winter 1994. Includes corrected counts and densities of species and species groups occurring

in both aerial and boat shoreline surveys during winter 1994 calculated for two survey widths: 0.1 nm and

0.2 nm, and in the three survey areas: Kachemak Bay shoreline, western shoreline and combined shoreline

(western and Kachemak Bay). The 0.1 nm width for the Kachemak Bay shoreline survey was not modified.

Kachemak Bay Western Shoreline Combined Shoreline

COUnt Density Count Density Count Density

Species Group' CF' 0.2 nm 0.2 nm 0.1 nm 0.2 nm· 0.1 nm 0.2 nm 0.1 nm 0.2 nm 0.1 nm 0.2 nm

Loons 8.1 268 2.5 6 6 0.1 <0.1 69 276 0.5 0.6

Cormorants 4.4 926 6.5 57 109 0.5 0.4 434 1,036 2.4 2.9

Waterfowl 2.1 13,666 125.9 2,593 9,419 20.6 37.6 10,254 23,107 55.6 64.5

Eiders 0.4 204 1.9 62 565 0.7 2.3 276 769 1.5 2.2

Harlequin duck. 6.1 2,104 19.4 1,416 2,200 11.3 6.6 2,636 4,304 14.3 12.0

Oldsquaw 1.1 231 2.1 472 1,252 3.6 5.0 553 1,462 3.0 4.1

Seaters 2.5 4,667 45.0 542 3,056 4.3 12.3 3,076 7,943 16.7 22.2

Goldeneyes 5.7 6,396 56.6 431 493 3.4 2.0 2,710 6,690 14.7 19.2

Bufflehead 21.3 2;301 21.2 0 0 0.0 0.0 256 2,301 1.4 6.4

Mergansers 0.6 1,160 10.7 61 115 0.5 0.5 797 1,275 4.3 3.6

Gulls 1.1 1,425 13.1 35 56 0.3 0.2 965 1,460 5.2 4.1

Alcids 0.3 1,999 16.4 0 0 0.0 0.0 662 2,000 3.6 5.6

Murres 0.2 1,471 13.5 0 0 0.0 0.0 466 1,472 2.6 4.1

Sea otter 2.1 592 55 142 369 1.1 1.6 293 961 1.6 2.7

• We did not calculate a correclion factor for Brachyramphus murrelets, because this species group was not sighted within the 0.1 nm

aerial survey zone.

• Correction factor w\ls calculated for species groups present on the aerial and boat surveys. CF = (boat estimate/aerial count).

55

:'>-'0
Tatlle 17. Densities (birdslkm2

) of species groups of marine birds observed on a small boat

survey of Prince William Sound during July 1993 (after Agler et al. 1994a) and listed by

stratum. .

Species Group Total Shoreline Offshore'

Loons <0.1 0.4 <0.1

Grebes <0.1 <0.1 . 0.0

Tubenoses 1.6 <0.1 1.7 , Shearwaters and fulmars <0.1 <0.1 <0.1

Shearwaters <0.1 <0.1 <0.1

Storm-petrels 1.5 0.0 1.7

Cormorants 0.2 1.5 <0.1

Watertowl 3.1 23.7 1.0

Scaup <0.1 0.1 0.0

Eiders 0.0 0.0 0.0

Harlequin duck 0.9 10.1 0.0

Oldsquaw <0.1 <0.1 0.0

Scoters 1.2 3.3 1.0

Goldeneyes <0.1 0.8 0.0

. MElrgansers 0.5 4.8 <0.1

Shorebirds 0.6 6.8 0.0

Jaegers <0.1 <0.1 <0.1

Gulls 13.0 72.3 7.0

Tems 1.0 4.4 0.7

j

Alcids 21.0 34.4 19.6

Murres 1.8 0.5 2.0

GlIillemots 0.4 2.7 0.2

Murrelets· 17.8 29.8 16.5

Puffins 0.7 1.1 0.6

Total marine birds 41.3 148.7 30.5

, The coastal-pelagic and pelagic strata of Prince William Sound were combined to form an

offshore stratum for comparisons with Lower Cook Inlel.

• Marbled and Kittlitz's murrelets only.

56

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I
:',1!p-

"

II':1

"I

"

I!I

"

,·1,I

,

"

'!I

!I

';

.,

:1

:.,1 I,

I,.

r.,. I

,

'il

:,.

Table 18, Densities (birdslkm') of species groups of marine birds observed on a small boat

survey of Prince William Sound during March 1994 (Agler et al. 1994d) and listed by

stratum. I '. .

Species Group I Total Shoreline Offshore'

Loons 0.2 0.4 0.2

Grebes 0.8 6,7 0,2

Tubenoses 0,0 0.0 0,0

ShealWaters and fulmars 0.0 0.0 0.0

ShealWaters 0.0 0.0 0,0

Storm-petrels 0,0 0.0 0,0

Cormorants 1.3 5.6 0.8

Wateriowl 14,8 119.4 4,2

Scaup 0.2 1,2 <0.1

Eiders 0.0 b.O 0.0

Harlequin duck 2.1 22.1 0,1

Oldsquaw 0.5 1.8 0.3

Scoters 2.3 10,6 1,5

Goldeneyes 5.9 47.2 1.7

Mergansers 2,4 22,2 0.4

Shorebirds 0.3 2..9 0,0

Jaegers 0.0 0,0 0.0

Gulls 7.3 33.9 4.6

Terns 0,0 0,0 0,0

Alcids 10,0 8,1 10.2

Murres 5.8 4.3 5.9

Guillemots 0.1 0.6 <0,1

Murrelets· 4.0 3.1 4.1

Puffins 0.0 0.0 0.0

Total marine birds 35.7 190.1 20.2

• , The coastal,p~lagiC and pelagic strata of Prince William Sound were combined to form an

offshore stratum for co;t.parisons with Lower Cook Inlel.

• Marbled arid Kittlitz's murrelets only.

57
Table 19. Relative abundance (%). listed by stratum. of marine birds observed on a

small boat survey of Prince William Sound during July 1993 (after Agler et al.

1994a).

Species Group . Total Shoreline Offshore'

Loons 0.2 0.3 0.1

Grebes <0.1 <0.1 0.0

Tubenoses , 3.8 <0.1 5.6

Shearwaters and fulmars <0.1 <0.1 <0.1

Shearwaters <0.1 0.0 <0.1

Storm-petrels 3.7 <0.1 5.6

Cormorants 0.5 1.0 0.3

Waterfowl 7.4 15.9 3.3

Scaup· <0.1 <0.1 0.0

Eiders 0.0 0.0 0.0

Harlequin duck 2.2 6.8 0.0

Oldsquaw <0.1 <0.1 0.0

Scoters 2.9 2.2 3.2

Goldeneyes 0.2 0.5 0.0

Mergansers 1.1 3.2 <0.1

Shorebirds 1.5 4.6 0.0

Ja.egers 0.2 <0.1 0.3

Gulls 31.4 48.6 23.0

Tams . 2.5 2.9 2.2

Alcids 50.8 23.1 64.3

Murres 4.4 0.3 6.4

Guillemots 1.1 1.8 0.7

Murrelets' 42.9 20.0 54.2

Puffins 1.6 0.7 2.0

, The coastal-pelagic and pelagic strata of Prince William Sound were combined to form an

offshore stratum for comparisons with Lower Cook Inlet.

• Marbled and Kitllitz's murrelets only.

58

!

••

•

•

•

•

•

•

•

•

•

•

•

•

I

I

I

I

I

I
'i

ii lI"""

"'1' "

"

iii i' '11

II"

'I

ill

!l.

:,;1 !I

;,1

i~1

,1

1:1

i'l

i'l

il

III

I;

1;1

il

'I

:;!

I

i, '

I

I

i,

I,

t

I

Table 20, Relative abundance (%), listed by stratum. of marine birds observed on a

small boat $urvey of Prince William Sound during March "1994 (Agler et al.

1994d). , 11---- _ Species Group I Total Shoreline Offshore'

Loons 0.5 0.2 0.7

Grebes 2.1 3.5 0.8

Tubenoses <0.1 0.0 <0.1

Shearwaters and ful ars 0.0 0,0 0,0

Shearwaters 0.0 0.0 0.0

Storm-petrels <0.1 0.0 <0.1

Cormorants 3.6 2.9 4.1

Waterfowl 41.3 62.8 20.9

Scaup, 0.4 0.6 0.3

Eiders 0.0 0.0 0.0

Harlequin dUCk 6.0 11.6 0.7

Oldsquaw 1.3 0.9 1.6

Scoters 6.4 5.6 7.2

Goldeneyes 16.5 24.8 8.5

Mergansers 6.8 11.7 2.1

Shorebirds 0.7 1.5 0.0

Jaegers 0.0 0.0 0.0

Gulls 20.4 17.8 22.9

Terns 0.0 0.0 0.0

Alcids 28.0 4.3 50.5

Murres 16.1 2.3 29.3

Guillemots 0.4 0.3 0.5

Murrelets' 11.3 1.7 20.5

Puffins 0.0 0.0 0.0

, The coastal-~lagiC and pelagic strata of Prince William Sound were combined to form an

offshore stratum for comparisons w~h Lower Cook Inlet. '

o Marbled and Kittlitz's murrelets only.

59
,

.

I'

I,IIIIIIIIIII

••••III
= '"'-7"-- ....,..=_~.-~~."__.' ':-::::::.,.,.....,.. ___~'",". ,- . .:: =...=-:" -;~ ""----:r;::'= ... _", :.=.' = -:=..:. .-;:~:.. =-=

--~-- ,_ .'iiiii~"'_---iiii- -_~- =..... ...

• - - - - - - - - -

Table 21. Coefficients of varlaliofl (CV) for species and species groups from re-stratification of the study area used for a small boal survey 01

Lower Cook Inlet during June, 1993. Sample size used to calculate the variance for each stratum was determined on Ihe basis of Ihe

population of total marine birds in Ihe stratum.

Original'

.3 nm coastal.

Distance from Colonies - (km)b Easl'West"

Species Original By% 5 nm coastal No coastal 5 10 15 North-South' No coaslal Coastal

Loons 0.30 0.28 0.26 0.26 0.27 0.25 0.25 0.32 0.29 0.34 Northern fulmar 0.36 0.33 0.32 033 0.34 0.34 . 0.35 0.31 0.26 0.25 Shearwaters 0.21 0.19 0.18 0.19 0.20 0.19 0.19 0.19 0.16 0.17 Storm-petrels 0.27 0.24 0.24 0.25 0.26 0.25 0.26 0.24 0.20 0.20 Cormorants 0.19 0.26 0.26 0.25 0.26 . 0.26 0.29 0.29 0.29 0.29 Scaup 0.51 0.96 0.94 0.90 1.02 1.04 0.86 1.09 0.98 1.02 Eiders 0.71 0.68 0.70 0.69 0.71 0.70 0.73 0.75 0.89 0.79 Harlequin duck 0.27 0.51 0.50 0.49 0.53 0.54 0.49 0.53 0.52 0.52 Oldsquaw 0.96 0.89 0.90 0.88 0.91 0.89 0.92 0.95 0.69 0.69 SCoters 0.73 0.68 0.69 0.67 0.71 0.70 0.62 . 0.73 0.88 0.80 Goldeneyes 1.00 . 2.14 2.14 2.14 2.51 2.68 2.01 2.01 2.04 2.04

Mergansers 0.50 0.49 0.48 0.48 0.51 0.50' 0.50 0.47 0.60 0.67 Shorebirds 0.42 . 0.89 0.89 0.89 0.67 0.76 0.83 0.94 0.93 0.91

Jaegers 0.43_ 0.39 0.38 0.39 0.40 0.39 0.41 0.42 0.48 0.52

Mew gull 0.45 0.83 0.82 0.80 0.90 0.71 0.77 0.71 0.75 0.76

Glaucous-winged gull 0.17 0.17 0.18 0.19 0.16 0.17 0.17 0.19 0.19 0.17

Black-legged killiwake 0.24 0.25 0.26 0.26 0.24 0.23 0.24 0.21 0.24 0.23

Terns 0.31 0.29 0.30 0.30 0.32 0.31 0.32 0.32 0.27 0.26 Murres 0.41 0.38 0.41 0.42 0.28 0.38 0.38 0.29 0.33 0.31

Pigeon guillemot 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.20 0.19 0.19

Murrelets' 0.14 0.13 0.13 0.13 0.13 0.13 0.13 0.11 0.11 Q.l1 Tulled puffin 0.18 0.16 0.16 0.16 0.17 0.16 0.16 0.14 0.12 0.12

Horned puffin 0.19 0.17 0.17 0.17 0.17 0.17 0.18 0.15 0.13 0.13

Total marine birds 0.13 0.12 0.12 0.13 0.10 0.12 0.12 0.10 0.12 O.tO

Sea oller 0.27 0.26 0.26 0.25 0.26 0.25 0.25 0.24 0.24 027

60

...
Table 21 (continued).

Species

Mean CV

Original'

Distance from Colonies

3 nm coastal (km)b East-Westd •

Original' By% 5 nm coastal No coastal 5 10. 15 North-South' No coastal Coastal

0.38 0.47 0.47 0.47 0.49 0.49 • 0.46 0.46 0.48 0.47

, The original stratification included a shoreline, coastal, and pelagic strata. Transects were re-allocated among these strata by marine

.bird abundance (by % of birds). We also examinedre-stralification wilh a larger (5 nm) coastal stratum and without the coastal slratum.·

b We re-stratified by creating a stratum of varying distances around colonies of >500 birds.

, North-south denoles re-stratification based on dividing Ihe Inlet inlo northern and southern strata at Anchor Point and placing

Kamishak and Kachemak Bays into separate strata.

• We divided the Inlet inlo east and west strata wilh a 3 nm coastal stratum and without this stratum.

• .Marbled and Killlilz's murrelets only.

61 •

------------------ -......j.....
_i_",_,_~ _~~_~

-~~~-~~'-~~--~-=-•

.. C--~ _. ~_..o'..

- -"'-

-

- -_.=~,.;;.. -:':-",",~"'" -
Table 22 (continued).

Original'

- 3 nm coastal Distance from Colonies (km)b East-Westd

Species Original By% 5 nm coastal No coastal 5 10 15 North-South' No coastal Coastal

Black-legged kittiwake 5.5 8 9.5 9.5 5.5 2.5 5.5 1 5.5 2.5

Terns 8.5 3 4.5 4.5 9 6.5 9 9 2

Murres 8_5 6 8.5 10 1 6 6 2 4 3

. Pigeon guillemot 4 4 4 4 4 4 4 10 8.5 8.5

Murrelets· 10 6.5 6.5 6.5 6.5 6.5 6.5 2 2 2

Tutted puffin 10 6 6 6 9 6 6 3 1.5 1.5

Horned puffin 10 6 6 6 6 6 9 ·3 1.5 1.5

Total marine birds 9.5 6 6 9.5 2 6 6 2 6 2

Sea otter 9.5 7 7 4 7 4 4 1.5 1.5 9.5

Total rank 158.8 129.5 130 131 154 134 138.5 139 131 129.5

Mean rank 10 1.5 3 . 4.5 9 6 7 8 4.5 1.5

• The original stratification included a shoreline, coastal, and pelagic strata. Transects were re-allocated among these strata by marine bird

abundance'(by % of birds). We also examined re-stratification with a larger (5 nrn) coastal stratum and without the coastal stratum.

b We re-stratified by creating a stratum of varying distances around colonies of >500 birds.

, North-south denotes re-stratification based on dividing the lrilet into northern and southern strata at Anchor Point and placing Kamishak and

Kachemak Bays into separate strata.

. d We divided the Inlet into east and west strata with a 3 nm coastal stratum and without this stratum.

• Marbled and Kittlitz's murrelets only.

63

-------------------..
= -::0":'=-"':","=." .=-:-==......,.::.

- - - - ... - - - ,:-'''':~ ---,' .

- -- 1IIi-'~ ~-

--- ...

'"-'~ -"'--=="-(~-~-"-~'-

Table 23. Coefficients of variation (CV) for species and species groups from re-stratification of the study area used for a small

boat survey of Lower Cook Inlet during June~ 1993. Sample size used to calculate the variance for each stratum was

determined by the abundance of common murresin each stratum.

Originala

,

3.nm.coastal Distance-from-Golonies-{km)" East~Wesl"

Species qriginal By% 5 nm coaslal No coastal 5 10 15 North·South' No coastal Coastal

Loons 0.30 0.36 0.39 0.38 0.38 0.46 0.49 • 1.43 0.47 0.49 Northern fulmar 0.36 _0.37 0.41 0.32 0.42 0.41 0.33 0.35 0.24 0.33 Shearwaters 0.21 0.21 0.18 0.19 0.24 0.23 0.19 0.24 0.16 0.19 Storm'petrels 0.27 0.27 0.30 0.24 0.31 0.30 0.25 0.36 0.20 0.25 Cormorants 0.19 0.71 0.96 0.91 0.71 1.16 1.41 1.43 1.26 1.41 Scaup 0.51 3.07 4.23 4.01 2.84 . 5.92 6.32 20.15 5.78 6.32 Eiders 0.71 0.81 0.97 0.99 1.01 1.11 1.72 1.66 1.41 -1.72

Harlequin Duck 0.27 L61 2.23 2.18 1.71 2.95 3.20 2.16 3.03 3.20 Oldsquaw 0.96 0.74 0.76 0.90 1.14 1.11 0.59 2.2,5 0.73 0.59 Scoters 0.73 0.55 0.56 0.67 0.86 0.86 1.25 1.41 0.99 . 1.25 Goldeneyes 1.00 7.09 10.02 10.02 7.09 15.86 5.78 5.79 5.78 5.78

Mergansers 0.50 0.84 1.12 1.09 0.87 1.28 1.43 1.00 1.53 1.43 Shorebirds 0.42 2.94 4.16 4.16 4.48 2.85 5.86 4.52 5.86 5.86

Jaegers 0.43 0.43 0.49 0.39 0.49 0.49 0.49 0.58 0.54 0.49

Mew gull 0.45 \ 2.66 3.71 3.60 2.48 2.42 2.15 2.72 2.10 2.15

Glaucous-winged gull 0.17 0.30 0.39 0.39 0.38 0.38 0.40 0.64 0.38 0.40

Black-legged kittiwake 0.24 0.48 0.62 0.60 0.68 0.43 0.41 0.44 0.38 0.41

Terns 0.31 0.26 0.25 0.30 0.38 0.38 0.25 0.61 0.27 0.25

Murres 0.41 0.31 0.33 0.42 0.16 0.25 0.20 0.20 0.31 0.20

Pigeon guillemot 0.18 0.33 0.42 0.40 0.36 0.48 0.56 0.37 0.51 0.56

Murrelelse 0.14 0.14 0.13 0.13 0.16 0.15 0.13 0.13 0.12 0.13

Tufted Puffin 0.18 0.19 0.19 0.18 0.23. 0.19 0.19 0.18 0.17 0.19

Horned Puffin 0.19 0.19 0.21 0.17 0.22 0.21 0.18 0.18 0.15 0.18

64
Table 23 (continued).

Original'

.. -

3 nm coaslal Dislance lrom Colonies (km)' East·West"

Species Original .By% 5 nm coastal No coaslal 5 10 15 . North·South' No coastal Coaslal

Total marine birds 0.13 0.12 0.14 0.15 0.14 0.13 0.12 0".17 0.13 0.12

Sea oller 0.27 0.40 0.51 0.49 0.59 0.39 0.34 0.30 0.33 0.34

Mean CV 0.38 1.02 1.35 1.33 . 1.13 1.62 1.26 1.97 1.31 1.37

• The original stratification included a shoreline, coastal, and pelagic strata. Transects were re-allocated among these strata by

marine bird abundance (by % of birds). We also examined re-stratification with a larger (5 nm) coastal stratum and without the coastal

stratum.

• We re-stratified by creating a stratum of varying distances around colonies of >500 birds.

e North-south denotes re-stratification based on dividing the Inlet into northern and southern strata at Anchor Point and placing

Kamishak and Kachemak Bays into separate strata.

. d We divided the Inlet into east and west strata with a 3 nm coastal stratum and without this stratum.

• Marbled and Killlitz's murrelets only.

65

----------------------.J
-..£.: = ,~ -=== ',.:=~ --~." ,=-:.: -- ...-='=:..' = .=-:-.''=:':'' -,.==..; ='.' . -::::_.,=':: _._. :.:. .. ~=...,....~.. -=-_.=...:..o===~-~ .::;':

- - - - - - -_.- - - - - - - - - - -

Table 24. Possible re-stratificalions of the Sludy area used for a small boat survey of Lower Cook Inlel ranked by species and coellicienl of variation

(CV). Sample size used 10 calculale the variance for each slratum was delermined by·abundance 01 common murres in the slratum.

Original'

Distance from Colonies

3 nm coastal (km)" East-West"

Species 0riginal--8y-%--.5-nm-coastaI-No-coastal--5 10 15-North·South'-No,coastat-eoastal •

• Loons 1 2 5 3.5 3.5 6 9 10 7 8

Northern fulmar 5 6 7.5 2 9 7.5 10 4 1 3

. Shearwaters 6 6 2 3.5 9.5 8 6 9.5 1 3.5

Storm-petrels 4.5 4.5 6.5 2 8 6.5 9 10 1 3

Cormorants 1 2.5 5 4 2.5 6 10 9 7 8

Scaup 1 4 6 5 2 8 3 10 7 9

Eiders 1 2 3 4 5 7 6 9 8 10

Harlequin duck 1 2 6 5 3 7 8.5 4 8..5 10 ':1.

Oldsquaw 6 3 4 5 8 7' 9 10 2

Scoters 5 3 ·2 4 6.5 6.5 1 10 8 9

Goldeneyes 1 6 8.5 8.5 6 10 6 4 2.5 2.5

Mergansers 1 2 6 5 3 7 8 4 10 9

Shorebirds 1 4 5.5 5.5 7 2 3 8 9.5 9.5

Jaegers 2.5 2.5 5.5 1 5.5 5.5 8 10 9 5.5

Mew gull 1 6 10 9 5 4 8 7 2 3

Glaucous~winged gull 1 2 6.5 6.5 4 4 9 10 4 8

.Black-legged kittiwake 1 7 9 8 10 4 6 5 2 3

66
Table 24.continued:

Original'

Distance from Colonies

3 nm coastal (km)' East-West'

Species Original By 'Yo 5 nm coastal No coastal 5 10 15 North-South' No coastal Coastal

Terns 6 3 1.5 5 7.5 7.5 9 10 4 1.5

Murres 9 6.5 8 10 1 4 5 2.5 6.5 2.5

Pigeon guillemot 1 2 6 5 3 7 10 4 8 9

Murrelets' 6.5 6.5 3.5 3.5 9 8· 10 3.5 1 3.5

Tufted puffin 3.5 7.5 7.5 3.5 10 7.5 3.5 3.5 1 7.5

Horned puffin 5.5 5.5 75 2 9.5 7.5 9.5 3.5 1 3.5

Total marine birds 4.5 1.5 7.5 9 7.5 4.5 4.5 10 4.5 1.5

Sea otter 1 6.5 9 8 10 5 6.5 2 3 4

Total rank 77 103.5 148.5 127.4 155 157 177.5 1725 118.5 138

Mean rank 1 2 6 4 7 8 10 9 3 5

, The original stratilication included a shoreline, coaslal, and pelagic strata. Transects were re-allocated among these slrata by marine bird

abundance (by % of birds). We also examined re-stratilication with a larger (5 nm) coastal stratum and without the coastal stratum.

b We re-stratified by crealing a stratum of varying distances around colonies of >500 birds.

, North-south denoles re-stralification based on dividing the Inlet into northern and southern strata al Anchor Point and placing Kamishak and

Kachemak Bays into separate straia.

, We divided the Inlet into east and west strata with a 3 nm coaslal stratum and withOut this stratum.

• Marbled and Kittlilz's murrelets only.

67

-------~----------- _._...
- - -- -~--=--==:- '::::'.,,= :=- ==-=:-:-" :.:.: =- ""-=--..::-:::.:. .:,:...~" :.::- -:;::...:'" ::. '-=, ':=''' ":: ::..:: =,- =. """'.:...::-'~.';:' ,='=:". ,.~- .=-=-:.:..- -..' =- :::..'=.0.;::: .=~:£:; .._,='..,. '","= .::;,::-..- ..:.:' --==. ~~ ..~:==- =....:.:.:= =- = = ".~:::.~= -:: ,,~~

---------------

Table 25. Comparison of power (%) to detect trends in abundance of marine birds for biannual surveys and for surveys

occurring every three years. We examined four levels of precision (CV) with an average annual rate of change of 10%. ,. - ..... .. .

CV =0.2 CV =0.3 CV =0.4 CV =0.5

• A' - Years Biannual 3 Yrs Biannual 3 Yrs Biannual 3 Yrs Biannual 3 Yrs

10 years 49 32 29 19 20 15 16 12

20 years >99 74 92 56 74 38 57 29

30 years >99 >99 >99 92 >99 74 96' 57

Table 26. Comparison of power (%) to detect trends in abundance of marine birds for biannual surveys and for surveys

occurring every three years. We examined four levels of precision (CV) with an average annual rate of change of 5%.

CV =0.2 CV =0.3 CV =0.4 CV =0.5 --

Years Biannual 3 Yrs Biannual 3 Yrs Biannual 3 Yrs , Biannual 3 Yrs

10 years 20 15 14 11 11 9 10 8

20 years 85 38 45 23 31 17 24 14

30 years >99 85 88 45 68 31 52 24

68
II

IiIIIIIIIIIIIIIIII
=..'. =-...::..:,:....-=- ,..= =.~'",". = ".= :;~ ..... ...:=-:,.,-:-;- = .. -==---==:.::-.:...- ==--==;;.. =-'=""....::,,-.•,.:.=.

- - - - - - - - - - - - - - - - --- -

Lower Cook Inlet

Km 59N

,=-...-----J

o 10 20 30 40 50

L-'-__~._. __.. __

Barren Islands

)};;c t?.,. auglas •

n 152'W __ .. __._~ ._L .

u9;;lsland

--- ._- - ..__.._.. _.._.,. _..

Fig. 1. Study area used for a small boat survey aI-marine birds and sea otters in Lower Cook Inlet, Alaska, during summer 1993 10 estimaie population

abundance and distribulion. -

69
,- - - .._._-

Lower Cook

Inlet

•

&7

l?'= d

Barren Islan s

I... N~. ·~I

Fig. 2. Study area used for a combined small boat and shipboard survey of marine birds and sea otters in Lower Cook Inlet, Alaska, during winler 1994 to

estimate population abundance and distribution. We divided the study area into 3 strata: shoreline, bay, and pelagic. The shoreline slralum is the thick

black line, the bay stratum is the light shading, and the pelagic stratum is the dark shading.

70

- - - - - - - - - - - - - - - - - -.
~O ~=-." .-_==~.=C . ''==:... ,--,...,-=""" --" .-,,', ~_. '.~ ~""=.=C ""'.== ,"- =~- .,~

- - - - _.- - - I

-=- =-=. ,. =.=---= :":"=.-.:::.:,. .-.... '-'-~:~-=- = .,,=...===- -.-..- . -= - "',- -=', .,"-"= --

- - - - - - - - - •

=",:,"",,=-.;:' ==

- -

. .4,

:,.

I!.

0J

<-

Barren Islands

Y!?~ ,

Lower Cook

@ Inlet

Kamishak Bay ...---------"'--------....-,.--" • - .. -'"

q - -_._-_.._.._ __ _.. .. --- . ---------------_...- - ---_. -,... -_....-

Fig_ 3_ Study area used for an aerial survey 0'- marine birds and sea otters in Lower Cook Inlet, Alaska. during winter 1994 10 eslimale populalion abundance

and distribution_ Circled numbers indicate segments used by Arneson (1980)_

71
,~~' ''''~(-''' 'f,:' , -_. -_. ~-~.. .._._-_._--_.- ---

.," ~!I

I

large gyre

be' 1".,. •

/ <3"'= , ./' .... 0:> .cq ,.- ........._--, Alaska Coastal Current

Fig, 4, The major currents and tide rips of Lower Cook Inlet that influence marine bird distribulion and abundance (after Burbank 1977). Solid lines running

north and soulh indicaie tide rips, Circles represent the position of small gyres in the mouth of Kachemak Bay, The Alaska Coastal Current (dark

. arrows) enters in Ihe southeastern corner, crealing a large gyre in the southern portion of the Inlet

, 72

- - - - _.- - - - - - - - - - - _.- -J.
____. __,_.. :_='0:::::::-",.:--._ ~\.- ..

- - - .=. _"=. '-..:., -:""=":'= ... =-= ':.:_ ..--,. ._. ,: .=--:=. - - _..- -

- -- - --.':..-=;::: =. ..,.-:::?,-.

- -

_. ""~_~~~iiio--

,.

·-f

.~~

-............-

,I

o 10 20 30 40. 50

-----------_.__.-

(b

y /?,p •

1->( .,._ ..

-,

Fig. 5. The 2-minute latitude byA-minute longitude grid used 10 separate starting locations of transects for a small boa1survey 01 lower Cook Inlet, Alaska,

during summer 1993. Because of our northern latitude, the 1,096 blocks of the grid were approximately 2 x 2 nm.

73

.~
Km

a--=----- 5 10 1520 25

J!Jyo l?",. •

A

r . .__

Fig. 6. Location of a 0.1 nm (200 m) shoreline butler and a 3 nm (5.6 km) coastal butler used in a survey of Lower Cook Inlel during summer 1993.

74

- - - - - - - - - - - .- - - - - - - -., [
-.o:;.~ = "=" ,=-:.: 0...=- -":==~== :::: ='-' "'-= .":.-- -::: ~:: .. ==--='?' ::. -_. -- =. =-~-= ..._..=:... .==-- = = .. := _.==-"=...,.......::. ::.

-------------------

"

.,;

,

.<

"•

1¥

•

._--_.-

Km

-=-==-

o 5 10 152025 ------_.. _~_. __ ._~y /?,p , ,

". I ~I'I-t-~-'-

III" II '1';

~,' I I_~ I I I 1_' }

I 'I

I I I I I I

I . I

I I I III II I II I I

I I I I I

I II I II I I I I

II I 11'1 1 III

I I I I I I I I)~ I ". I, I. I I :

11

• 11 11111 II d

II I1I1 I ' I I I I ,I I I

I I' III I I I I I . I I 1'1 I I I I

. I d II

Fig. 7. Randomly-chosen transects (2 nm in length) used in a small boat survey of Lower Cook Inlet, Alaska, during summer 1993 to eslimate populalion

abundance and distribulion of marine birds and sea oilers. Dark lines along the shore indicate shoreline transecls.

75
Shoreline

Bay

Pelagic Lines

Pelagic Segmenls

Boundaries

Transects

I... :m..~I @sI

!;I

r: I

...,I';'·· (f<p p

Barren Islands

Lower

Cook Inlet

•

Fig. 8. Transects used in.a boat survey 01 Lower Cook Inlet, Alaska, during winter 1994. The shipboard survey of the pelagic slralum surveyed 9 lines (thin

. lines), then we selected 85 2-nm segments (thick lines) to calculate our eslimates. The bay and shoreline lransects were surveyed from small boals.

76

-------------------
_ ......-.-::;--== =:.... ..:-"::=="--=- = = :--:-:- ~= =--=.. ,.:..::i:::::....-=' =:===-= c-.~::.:.::.,·-=--:: :;:.•_. =:'':"••• ::=.- =- .:::....-..=.:.-::..:= =-

- -- - - - - - - --- - -,- - - - -

r.i _. . ._ .

............ ... _.,-~ ...

J,

Km -==-=_-::- o 10 20 30 40 50

----~------_._..-

"

;

•..

'.. 1. .,:,

...' .J.

i

·i

. :J

Fig, 9, Location of eastern and western strata used to investigate rnethods to improve the precision 01 the population estimate from a survey of Lower Cook

Inlet during summer 1993, The 2 strata were further stratified into Ihe pelagic (pallerns) and shoreline (dark lines) strata for a tolal of 4,

77
·r [

Km

..--10 20 30 40

-

50

Fig. 10. Location of eastern and western strata used to investigate methods to improve the precision of the populalion estimate lrom a survey 01 Lower Cook

Inlet during summer 1993. The 2 strata were further stratified into the pelagic, coastal, and shoreline (dark lines) strata lor a total 01 6.

------

78

-----,--------
._

=;;;C- __ ~~_A=~ ~~~_~""~ __~~-_- -..--a ~"_~_""-_~'~_ "~_~ .• -

- -

I ... __ . _

-- _...-. ..-...-•. -

~e-

';/1

<F::~

I Km I

o ';;--20 30 4~

'j:

.- ",::\

"-~ ,

"- <,,::"

Fig, 11. Location of north, Kamishak Bay, Kachemak Bay, and pelagic strata used to investigate methods to impwve the precision of the populalion eslimale

from a survey of Lower Cook Inlet during summer 1993_ The first 3 strata were further stratified into the pelagic and shoreline (dark lines) strata for a

total of 7~ .

79
-::-""-~---~~--'I '

Km

_iiiiiii

o 10 20 30 40 50

":"'

-'-----.,.-----------------_.-------_.._-

Fig. 12. Location of a 2.7 nm (5 km) buffer around colonies with >500 birds used to examine re-slratification of Lower Cook Inlello improve precision of

estimates of marine bird abundance. These strata were stralified into shoreline and pelagic slrata.

80

-- - - - - '- - - .- ,- - - - - - - ---.,..
,==- ~.-., "..::"'-= .•=. =-. -:..,,-'..:- =,::.:::'.= . .,...".--.,.~""=="~=.::: ::. -==--='.~:.- - .,:.:.:...:::=:..::<:: . ::':._-::. -_.. =-:-::=..:::~. :-=-~==_. ._--=_ -=-.::-:'::=: -=-=- ,. =-= "~...=:::-=-~..,.-.::.=.;....::::.=.~.,,==,?r. -:="'="=: =, :-:--.=:.::::.~:~.,:.. ';':"-...0..::.::-...:=. :='::..=-~: -- -

_.- - - - - - ,- - - -..- - _.- -

... .-

--'''''--

..:.,.

'1,,;:'

" '.~

1

:~

•

. -"".

.'

..71

!1ir

Km

---

o 10 20 30----=- 40 50

if "''- r·

•

Fig. 13. Location of a 5.4 nm (10 km) buffer around colonies wilh >500 birds used to examine re-stratificalion of Lower Cook Inlet to improve precision of

estimates of marine bird abundance. These strata were stralilied inlo shore.line and pelagic slrata.

81

:~

'<~
/ Km

.0iiiiii:l0==2]Oiiiii:30==4~ ~!

--_._- ---------+--,._------- -~-,. -~. _ .. _~-~_ ..

Fig. 14. Location of a 6.1 nm (15 km) buffer around colonies with >500 birds used to examine re-stratificalion of Lower Cook Inlel to improve the precision 01

estimates of marine bird abundance. These strata were stratified into shoreline and pelagic strata.

82

-------------------
• - - _•.c:.. ".----..-

- '. -- - = = '-'=-= .====-:::..,.:.~...,.,

• _ • "'"-"- .. ~~"" 'F'--"? "~, -=~""~"'~~~, ~,

- -" -.::-:---==-~- ==...-==: -.-;:'="=== - _.. -==.":-::.; - _. -;;::_.,=-

- -

..---_......_-

't,.

Km

~O-·,'::O--,2~O-·30~~40 -.-50

" I

-----------~-~----_._-------- -_._-

--...,~ ...

_....

;;;~ .

....

'.

,

.

i

Fig. 15. Location of a 0.1 nm (200 m) shoreline stratum and a 5 nm (9.3 km) coaslal sfralum used to examine re-straliticalion of Lower Cook Inlet to improve

precision ot .estimates 01 marine bird abundance in future surveys. .

83

I
i 'i,.-":' '~"'~'I ~_~ ,__, •.:. ~, _

Number of Birds

15

30

60

125

250

" 5

., I....'m•• ,,]

C:>

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u

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Fig. 16. Summer distribution 01 marine birds from a small boat survey of Lower Cook Inlet, June 1993. Each circle represents one transect, and the size 01

each circle is dependent upon the' number of observations for that transect.

•

- - .' - - - - - -

84

- - - - - - - - - -
.-:=-,..:: -=-==.:..:.:=-- .=~ .. == =-=.. ':':"::..-= :;.-::=. == =. - """"-=:=:-'10"'=':"" -::'='= "-" ..=:~= -.=-::;;-,::.."=.-::' ,~""";-.:.:.."::;

- -

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--- -- - - - - - - --

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o lLO-c20'_·30~- 40 50

---------

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n

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Fig, 17, 'Summer distribution of tubenoses (shearwaters, fulmars, and storm-petrels) from a small boat survey of Lower Cook Inlet, June 1993, Each circle

represents one transect, and the size of each circle is dependent upon the number of observations for that transect.

85
·"'H ~-------_..

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.',..p', " .l '.','

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125

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Km - -;;;;;;

o 10 20 30 40 50

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Fig. 18. Summer distribution of northern fulmars and shearwaters from a June 1993 small boat survey of Lower Cook Inlel. Each circle or star represents one

transect. and the size of each symbol is dependent upon the number of observations.

86

- - - - - - - - - - - - - - - - - - --"'-
- - .

-._- - - - - -, .. .,: ::,:.,.. -=::". =- .,..=._~ ::::,:,:::=,_"-:::::.,=::=~: =:. ""=:.:.= ,:;: .':!~_ -==-__= .:==----0=-- =--.:... _-=---=--== - -_. - ,_.- _, __. ~.".-=.. _".=_ .. ._---'"'"_.._ .. _._ .. __.. _ .__.__0- _. .Joe. ...__ '"••••

-''''4L---'-,.. ---'--.-.----,.:- -.-.-.-.---.,-- .,.,.--.., •.- • _.- =w;.;.:..-==-=- = =.==. ::::.:.:.:...,=. ~7="~.

'-'..",

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50

3

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--

" .._- _.- .. _._.. --_._~-----_... ~_._----- .._... _.. . _._-

---------"_.•

Fig_ 19. Summer distribution of fork-tailed storm-petrels from a June 1993 small boat survey of Lower Cook Inlel. Each circle represents one transect, and the

size of each circle is dependent upon the number of observations for that transect.

·87
Km

iiiii=:= -_ o 10 20 30 40 50

e,

I!'... ,

(',

(;

.)

i~B;:"";'qrll, I

...... _------ -_._-

,,,-

,

Fig. 20. Summer distribution of cormorants from a June 1993 small boat survey of Lower Cook Inlet. Each circle represenls one.lransect, and the size of each

circle is dependent upon the number of observations for that transect.

- -_.- - - - -

88

- - - .- - - - - - - -
===-,- ""'- ~. -=- .....:.:....-=. =- =-=-==.:..:.: .:== ,,;-::. .-=.~..:.:-.=::.- .~=.=. "-= """- .:.... -=.''::'=;.-'=~'= "::""- -= .=. ..,=-===--.:,.. ,.=..=~ ~.,....:..=.;o -::::::--.:.; .= ._- -- .._.- "'-=, .•", ="-""':' =='~~='.- c:::" ."::._...•'""'-' =-,-- -

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- .- - - -- "~·· ~.

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t,

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..... -""""

,

Fig, 21, Summer distribution of watertowl from a June 1993 small boat survey of I,.ower Cook Inlet. Each.circle represents one transect, and the size of each

circle is dependent upon the nl!mber of observations for that transect.

89
l~

Y I?", ,

ct:>

""

[ -1 Km

o--10 20 30-==- 40 50

~._."._-~------_._.._..

Fig. 22. Summer distribulion 01 gulls from a June 1993 small boat surVey of Lower Cook Inlet. Each circle represenls one transect, and the size 01 each circle

is dependent upon the number of observations for that transect.

90

- - - - - - - - - - - - - - - - - _.-
= ..:.:.: ~'=iC--=-"=:='=.~ ..:: = :.....:.;:-.~ ...:.:...=:-."=..;.;:.....:== ...<.~ •• ",:,,--'•.:;:::"" "::..':=. -=.. ,::''":::,--=--c- ~.=-. ~,.~-::, ..: =.=:.-=-=-= ::-= .=='~""='.-=~"-=:==.-.--'-=,,"..._''-:::::: .~7.",,-.:.- .. ..-...---=-:.:= =- =--=== . _._-=="~:,:""_._,=.:=::::'.-.=.....==::: ~.:::--==- .-=.=:"-;:' .::. :::.-/.~

~_~_"""'_""""iiii~iiii~'''''~ __~_~_~--~. - ==t~_,..-~~.l~~. "~.,;, ~=;oo;=-_~_·:;;;,"4·

........ ,:_. ...if .."

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. ,

(,

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o ( ,

'.l

)yo, d""""

<0

Km

o--10 20 30----=- 40 50

L-. _

• .,,;..

0\;

"

Fig. 23. Summer distribution 01 terns Irom a June 1993 small boat sUlvey of Lower Cook Inlet. Each circle represenls one transect. and Ihe size 01 each circle

is dependent upon the number of observations for that transect.

91
•

3

2S

6

12

50

"00

-_._._.. -,-._._._-_.

Km--'----l o 10

--~=- 20 30 40 50

---'------~-----

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( . 'J ')U cO (l ~)(;()

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() .. ,'U

<) - ( .. ',:) ()

••

Fig. 24. Summer distribution of alcids from a' June 1993 small boat survey of Lower Cook Inlet. Each circle represents one transect, and the size of each

circle is dependent upon the number of observations for that transect.

- - - - _.

-

- - -

92 .

- - - - - - - - - -
=::.C'-,::"'=:..=.-.= '--:.:;.-._-=: ---.. -::..-:=- '.. ='=---'="" -:-.=....::::=' . ..:.::.:;=~.=.... ==~..,= = _._.- £= =C::;=::"~="=_=c:.:....-:-:'" ."",..~::-.=..._--,,= ....=::: ..-=-~~-==. .._:.~,",,::,-=-" .... =. ===C:_._E":::~~,.::' =:_- ="'=='.:::=== =- ":':"-'.

-....-_-----... .. __--'iiiii----.-----,__..--...'_~_-,·..-·-== - _,_._.==._._._'.===.__.'==__,.==.-.....o;==..=.--~._~,j

'I

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35

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E --------J Km ,

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Fig, 25, Summer distribution of murres from a June 1993 small'boat survey of Lower Cook Inlet. Each circle represenls one transect, and the size 01 each

circle is dependent upon the number 01 observations for that transect.

,

93
,

'1 ,"> ()

n

5

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Fig, 26, Summer distribution of Brachyramphus murrelets from a June. 1993 small boat survey of Lower Cook Inlet Each circle represents one transect, and

the size of each circle is dependent upon the number of observations for that transect.

- - - - - - - - -

94

- - - - - - - - - --
':.. ~"""i"':;':':.'_C::"E",.,,= ="-'=.. ....::.:.~ '-~-=_i;:' =-:- Co ==~---=-.. .:.:. ::.::=:.

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65

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Number 01 Horned Pulfins

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Fig_ 27_ Summer distribution of tulled and horned puffins from a June 1993 small boat survey of lower Cook Inlet. Each circle or star represents one transect.

and the size of each symbol is dependent upon the number of observations for that transect.

95
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. ;:.:.:-.._='':'':--' = .::.---:.;..=-= -=--==::..:-"'-:--:-.- ::-._~_ :::.=':""'=:'" :::o::z===-: '.:=...:.=._= ..=-=== _.__. ~,.,c==..::., ,-.:;..-:-::;... = .. ==::.~ ..::.:::=.::.... :.:.=~.,..=. -F='""::: =:..: ="-

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Fig_ 29, Summer distribution of sea otters from a June 1993 small boat survey of Lower Cook Inlet. Each circle represents one Iransecl, and the size 01 each'

circle is dependent upon the number of observations lor that transect.

97
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'lilfW .... _._._-_..,---~- .__ .

Fig, 30, Winter distribution of marine birds from a February-March 1994 boat survey of Lower Cook Inlel. Each circle represents one transect, and the size of

each circle is dependent upon the number of observations for that transecl.

- - - - _.- - - -

98

- - - - - - - - - -
=:-:=..:=:::-:::..= .. .--- ··'L-====·'''::>':'=--==-~:'==::',=-=--=~ "~':..-":"...:.:.. -::...:..~ ..;.,=,:"-= _":"_c--'''::=--==,';::EL:=--_'':'':::''. -=. -=."0•• -::....::.-==-= "_".:::'=-"i-' :....=- __ ..:,:::,-_.=.~ ',.,,;.;?"":"..:...~..:::::' _-= _.~"--=;:--='-==-__.'.="'== =

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I

i

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I

Km

O~--=-5--:1O' --~-15 20 25

l?o I .._._n . . , 1ItllP ---- n_

..__. ... _---

Fig. 31. Winter distribution of loons from a February-March 1994 boat survey of Lower Cook Inlet. Each circle represents one transect. and the size of each

circle is dependent upon the number of observations for that transect.

99

..1.
•

I]

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r .

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J1fyo .~~ < II l?,p

.

I

Km

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o 5 10 15 20 25

I u_

------------------------

•

~~

Fig. 32. Winter distribution of grebes from a February-March 1994 boat survey of Lower Cook Inlet. Each circle represents one transect, and the size 01 each

circle is dependent upon the number of observalions for that transect

-------

100

------------ - ...
=::=,::,,0..= ... ...:.. =~ ==,,:,,:;,,-_. "':"':.'" -=...:.=-==~.==--= == ·=·=C",,",,",'.· . .:.._.- - =.:::'::;:,':':= ~=:-"='i-- :- ., =-: "':=:.:.....,_-::;=-~-..:...,---=~_ ... :,~---=--.j~_ ...:S~,=-.i='-':==:~.:==_......,.. ,.=:"=:::=-'?''''::_::=--= -~'::,- ...:....--="=_..:.:. :="',-:.== _-::.-=

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lOj1'i' . _ . ---_._------_~ .- ._- _. ---,._~-_.- -~_.

Fig. 33. Winter distribution of cormorants from a February-March 1994 boat survey of Lower Cook Inlet. Each circle represents one transect, and the size of

each circle is dependent upon the number of observations for thai transect.

101
o

I

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@D

-=--..:_- Km l

: __ _~~ .. .2:.. 25.. ..

----~~--~--~~~~. __ .._~~

Fig. 34. Winter distribution of walerfowl from a February~March 1994 boat survey of Lower Cook Inlet. Each circle represents one transect, and the size of

each Circle is dependent upon the number of observations for that transect.

102

- - - - - - - - - - - - -.._.,- -_.- -
-F::-"::= =-

- - - =~-~,'- ,';,c, ==,~-.='"-~ --~- ~~"~ _,c.~.. _ ~--",,-":'~~~"'~'" =~"="~~-~~~,,-~--='-,,"",,,,,~~"·"-=~5=.·· .~~ ~7',=""'_-"-" .- "-~ =~_.~."- ="_1

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6

6

2

Number of Steller's Eiders

Number of. Common Eiders

ir 3

17 2

I--=: Km

L:::~5=:=J101II·'5;==:2~5

o

/l',p

, i

I

· '

,r--J j-"

I

,•I

:art;' .__.

-~----_.- ---- - _.._.. -_... -

•

__..........

Fig. 35. Winter distribution of eiders from a February-March 1994 boat survey 01 Lower Cook Inlet. Each circle or star represenls one transecl, and the size of

each symbol is dependent upon the number of observations for Ihat transect.

103
Km -]

05. --~O 15 20 25·

----- -_ .

"Ie--- "-- ._-_. - ._- .. -- -~---_ ...__._---- --_..

Fig. 36. Winter distribution of harlequin ducks from a February-March 1994 boat sUlvey of Lower Cook Inlet. Each circle represents one Iransecl, and the size

of each circle is dependent upon the number of observations for that transect.

104

------------------ --_..
£',=-:=,,-,-.:::::::::::_ :_-:: =--=. ~=_-=7.::.:.:=_....:.==,=. ::: :...:=-:=_-=- :.::""""'" ='i:I:.~~-,,,,"--,,::,,,:,:'_-"-~:o..~::;.....c=:.:=:::::-=-~:_'=:":::=::£:..~"';:;"=='=-.:=_.i'--:::l~--::::" -~--". ..,-='.::;.;:., ,_.---;:

- - - - - - - - - - - - - - -, - - .- -

,=: ~:.' :.:=. :.:.: = .:'_'-:"-=:-_- =,.::::",0:-::"' -i:,== ...:.....c.-===== .-=-..:..._~-==

-_._._--- -

I

r'

,,1

,

•

f:~'

-'- _.

,.

I ---

:JiJyo P' t1 l?,p

Km

0·--5'--'0 --~==­ 15 20 25

I

Fig. 37. Winter distribution of goldeneyes' from a February·March 1994 boat survey 01 Lower Cook Inlet. Each circle represents one transect, and the size 01

each circle is dependent upon the number of observations for that transect.

105

......
l

I

I

I [ 1.[--

,....

y If',p ,

&

Km

!O·~5=~,~O!llll~,5=::;2~5

, ..~-_._~.._---_.._---

Fig. 38. Winter distribution of oldsquaws'from a February-March 1994 boat survey of Lower Cook Inlet. Each circle represents one transect, and the size of

each circle is dependent upon the number of observations lor that transect.

. -

106

-------------------
-=_,==.. ~-==_:=-._ ..,.. .,==.. -:" -:-=_-=. ===:, •. _.....:....:. ,==.: ==..:. ,=:-"_-::," _: -=,,~-,. =.-.:- ===== '" _.. -.~ ..-.. :::=.:.:..:.;::..•. -:,:;;~c.::.::.:..'-_~.:_~::=;=_-=.-= __ .. - - -=:-=-=..=...~==:;;...:..~" ,==.==._",=,;.~- .~.=- ·'1

-

.,,- "'.~~

- - - - _.- - - - - - - - - - - - -

o

U

i·1

i'

I r'O

•

I

I [ 1,1-~

Km

0--5~-'1O --==- 15 20 25 .Jiv' If',p •

:'Pf'U" _.. _~._-_.

,-_._-- _._-

Fig. 39. Winter distribution of scoters from a February-March 1994 boat survey of Lower Cook Inlet. Each circle represenls one transect, and Ihe size of each

circle is dependent upon the number of observations for that transect. .

107
I·····::····················

J

,.. , ".J

,', (",

::-" ,

'.:'

I

i I . e;, Qi;J

_r==__Km .

o 5 10 15 20 25 b If'c- 1 ••• u _

•

jlM:FWif' . . . .. .

.. ... .._.

Fig. 40. Winter distribution of gulls from a February·March 1994 boat survey of Lower Cook Intet. Each circle represents one transect, and the size 01 each

circle is dependent upon the number of observations for that transect.

- - - - - - - - -

108

- - - - - - - - - -
...-:::,:.;==-=::::::...=1

- _~-'"~._~"-".,._.-. 0..--.,..~'.,.~~'=_""~_=-.,... --=,iii --~iii - - - - -- "...•"'._-=iij O. .~ __'~.~._~~.~'"""-_••••••~~_•• .,..~o"-.~_,,=- .,. ·"-~.,.o_~~~

-f

o 5

Km.__-J '·O-_,L5-""'20 25

I . ._.._ ....

t&

!?,p

() n

00 o !II

.J ()

•

~) (> <Ii " J

.r

("1

(, ()

.)

,> (, U

<)

" u i}

(\

c· 0 U

.:) ,)

"

- ....... .....

Fig. 41. Winter distribution of alcids from a February·March 1994 boat survey of Lower Cook Inlet. Each circle represents one transect, and the size of each

circle is dependent upon the number of observations for that transect.

109

••
JY""IV " .__ . __.__ . _

Km ---I --==-iiI;=- '

o 5 10 15 20 25

----- ~--

I,

o

y l?,p •

.:' ( . .~)

""j " - - - (\ '.-) (J

() 0(' n' e, (I

, fJ

" 1,'\

," [ 1,,:: ",I; .,

I ';; I

I ().'J

'F 1--1 -- II

I

J

Fig. 42. Winter distribution of murres· from a February-March 1994 boat survey of Lower Cook Inlet. Each circle represents one transect, and the size 01 each

circte is dependent upon the number of observations for that transect.

110

- .- - - - - - - - - - - - - - - -- -- _.
==:.-=0::..."'=""," ..,::.=='!r::._

- - :=...:.:.:. .•= -=·=;---::::.::::!::=:'o.·..---::.~,"·==:~..::: ..,.".--=--:: , .._-==..-=_ ='-_-:-:::-o'--==': ,...-=-,~---: ==..:::.,,:'=-..~~":l:","''''::_,':". -'=:'"•._. _~: .~_ • -="":-:"~-'I='""":_= :--'::....:.:.. '-=-="=-=--=.E="'~-:-'-~-===- _"",,:Coo'=:..' ."==- o·,~· -=,""- "=..==:;",,.,.-,-, .- '=.=_:=_'=-,.,.::: - .. - - - .- - - - - - -,-.

- - - - - -

,

.~

:~

••

-_......'-.

r'

,,

,',

..: ii'

-1 c' u

I

I " 'I r·r,.. I ,

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i·············· ·····1 I I , ,

,I II

"';;'.. '.L A.: J.',._;/~~P:';,._;;;,,; .;.,k,_~''''':,.,''~..::";';._>..'.;.".".'''.' •• , ....; " ;~,. II

_.... ~---

Km

)&0 l?o , o 5 10 15 20 25

Fig, 43, Winter distribution of Brachyramphus murrelets from a February-March 1994 'boat survey of Lower Cook Inlel. Each circle represents one transecl,

and the size of each' circle is dependent upon the number of observations for that transect.

111
W!W1rlI:£f~?"I&r" . m __

.- .__.. _. _.•

OCO

() 0

()

()

( )

, J-:-

----.-J J

U p l?.c>

o 5

,

Fig. 44. Winter distribution or pigeon guillemots from a February-March 1994 boat surveyor Lower Cook Inlet. Each circle represents one Iransect, and the

size of each circle is dependent upon the number of observations for that transect.

-_ ...... --_.,........-...... _--

112

-------------------
.==::=:-= =. -==.

.. .:: ."""...

- r.:;:.:':' ",~.- .-::::::::0-:-...=.::- '':':' -=::.-::-...::.~:-:"=--,-~"::.::= .~==,. =-"':::-."':"__-::::~ "'._~-

------ ,=.. ,~~-,=,,-,::i::.:-..:::==' :5" _::.. =-::.. ~~-= =:==''-~,=".=.~ - - - _.- .~.","~";:"'"",-==.,~~,,,,_::.-=- ""-"-=".-::."::::.-=....::::::::=.:::..:- .=-==..---== -~=,_:".,--..,:..:.#=:.I

------

•

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~. @v 'Q

l· ~~

I

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I f' r~! J~"

.---------- - '+

I

Km

;'~f.'i[;\f .. ..__

.~.._.- -_.. --

ll',p •

~O-~5--I~O--li--2~5

Fig. 45. Winter distribution of sea otters from a February-March 1994. boat survey of Lower Cook Inlet. Each circle represents one lransect, and the size of

each circle is dependent upon the number of observalions for Ihat transect.

113

...
Fig. 46. Power to' detect trends in marine bird abundance when confidence level is 0.10 and: (a) mean

coefficient of variation is 0.2, or (b) mean coefficient of variation is 0.3.

114

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Average rate of change

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Average rate of change

/

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0.1

/

,

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Number of surveys: 15

Q)

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1

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Average rate of change

0.2 0.3 0.4 0.5

Average rate of change

10

!

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./

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Fig, 47, Power to detecn ends in marine bird abundance when confidence level is 0,10 and: (a) mean I • .

coefficient of variation is 0,4, or (b) mean coefficient of variation is 0-5, , .

~i

i'l .1,

,I

II"

!ll "

III :1

if

,Iiii

..

'III

Ii'."

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IIIii ,\

il

il·h

il

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fp

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enE

l'l c

I,,1 10 ,i .... r

I'IIIIIIIIIIIIIIIIII
'~-';"" ',' : -'

I

I

I

CI

o

74

148

74

67

193

1,005

o

o

o

o

o

1,005

o

o

o

1,005

4

1,777

74

480

1,850

43

379

, 126

406

Winter

66

427

155

648

N

o

44

176

38

46

304

1,056

o

o

o

o

o

1,056

o.

o

o

1,056

2

5,556

40

695

6,294

1,252

1,039

149

1,232

2,497

57,488

60,101

124

60,099

85,022

33,368

15,460

13,223

,37,836

43,421

8,830

2,179

1,828

123

2,544

6,674

47,168

25,036

10,550

70,219,

105,805

12,533

165,507

,

I

I

!

I

,-

117

t

Appendix A. Estimated population abundance of marine birds (N .+ 95% CI) from small boat surVeys , ,-

of Lower Cook Inlet. Alaska In summer 1993 and a combined small boat and shipboard survey

"dUring winter t994. Species are listed in phylogenetic order (AOU 1983).

I

Summer

Species N CI

LOONS l' Red-throated loon (GaVia stellata) 242 283

Pacific loon (Gavi pacifica) 595 765

Common loon (Gavia immel') 392 266

Yellow-billed loon Gavia adamsil) 63 124

Unidentified loon (IGavia sp.) 1,270 1,207

Total loons (Gavia spp.) 2,5631,492

GREBES

Horned grebe (P

1

iceps auritus) 0 0

'Red-necked greb~ (Podiceps grisegena) 0 0

Unidentified grebel (Podiceps sp.) 0 0

Total grebes (Podiceps spp.) , 0 0

TU'BENOSES '. 1

Shearwaters and Fulmars (Family Procellariidae)

, Northern fulmar (1ulmarus glaeialis)

Sooty shearwater (Paffinus griseus)

Short-tailed shearkater (Puffinus tenuirostris)

Unidentified shear{...ater (Puffinus sp.)

Total shearwaters)(PUffinUs spp.)

Unidentified fulma or shearwater

(Fu/marus or PUffinus sp.)

Total fulmars and khearwaters ,

(Fulmarus a,ndl Puffinus spp.) •

Storm-petrels (Famill{ Hydrobatidae)

Fork-tailed storm-Petrel (Oceanodroma furcata) 113,804

Unidentified stormjpetrel (Oceanodroma sp.) 63

Total storm-pelrels (Oceanodroma spp.) 113,868

Total tubenoses (Grder Procellariiformes) 279,375

CORMORANTS "I. ,

'

Double-crested cormorant (Phalacrocorax auritus)

Pelagic COlTl'lCit8ntl{Phalacrocorax pelagicus)

Red-faced cormorant (Phalacrocorax urile)

Unidentified cormdrant (Phalacrocorax sp.)

Tolal cormorants (lphalacrocorax spp.)

I

I

ii

',i:. IIii

i·il

'I

ili,l

"I.

:1

II

,II

"

'il

~!

Appendix A (conti ued).

" 'I--I '------------

1

Winter

N CI

840 677

0 0

0 0

0 0

0 0

0 0

0 0

0 0

2 4

2 4

23,749 9,587

38 74

1,620 625

25,406 ,9,603

2,914 1,398

0 0

0 0

0 0

2,848 988

212 178

10,742 2,594

0' 0

2,487 2.642

16,089 4,752

0 0

0 0

0 0

0 0

89

426

426

CI

3,081

32

7

6

13

2,054

1,297

3,686

856

335

3,885

538

631

373

15,948

35,791

2,465

40,896

135,747

o

597

135,741

Summer

N

511

511

e,791

40

3

3

7

1,704

825

5,512

587

296

6,394

441

721

190

47,841

75,920

3,833

128,946

168,446 , 0

746

169,192

119

j

I

" Guillemots t

Pigeon guillemot (Cepphus columba)

I

,

I

1

I,

Species

I ' HAWKS AND EAGLES

Bald eagle (HaliaSetus leucocephalus) 347

, SHOREBIRDS 1 "

Black oystercatch r (Haematopus bachmarJl)

Unidentified yellowlegs (Tringa melanoleuca or flavipes)

Spotted sandPiPerl(Actitis macUlaria)

Whimbrel (Numenrus phaeopus) , .

Red-necked phalarope (Phalaropus lobatus)

Unidentified phalatope (Phalaropus sp.)

Total phalarope (~halaropus spp.)

Unidentified shorebird . 53 70

Total shorebirds I' 107 87

(Families Haematopodidae and Scolopacidae, except Phalaropus sp.)

JAEGE~S ': I- _ Pomarine jaeger (Stercorarius pomarinus)

Total jaegers (Steteorarius spp.)

GULLS _ I

Bonaparte's gull (li.arus philadelphia) - I Mew gull (Larus canus)

Herring gull (LaruS argentatus)

Glaucous-winged gull (Larusglaucescens)

Black-legged kittiwake (Rissa tridactyla)

Unidentified gull (Uarus or Rissa sp.)

Total gulls (Larus ~nd Rissa spp.)

TERNS

Arctic tem (Sterna paradisaea)

Aleutian tem (Ste a aleutica) , Unident~ied tem (Sterna sp.)

Total tems (sr.mil Spp.)

ALCIDAE '1 '

Murres t

Common murre ( ria aalge)

Thick-billed murre I(Uria Lomvia)

Unidentified murrel(Uria sp.)

Total murres (Uria spp.)

"'. I!

,

•

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'i!

'!

'I','il II

,j

:11

;:.

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1:--

i

l

.,

I,

-I

i',','. ,'I

I'

,
---------

If

Appendix A (continued). I

Summer Winter

Species N CI N I CI

Murrelets I

Marbled murrelet (Brachyramphus marmoratus) 7,782 2,726 7,449 6.163

Kittlitz's murrelet (Brachyramphus brevirostris) 3,353 1,718 0 0

Unidentified Brachyramphus sp. 47,092 14,004 4,178 2.349 I

Total Brachyramphus murrelets 58,227 16,058 11,627 7,410

(Brachyramphus spp.) I Auklets

Parakeet auklet (Cyclorrynchus psiltacula) 63 124 0 0

I I

Puffins

Tufted puffin (Fratercu/a cirrhata) 37,737 12,946 0 0

Horned puffin (Fratercula comiculata) 26,369 9.696 '0 0

Unidentified puffin (Fratercu/a sp.) 2,792 1,694 0 0 I

Total puffins (Fratercula spp.) 66,899 16,409 0 0

Unidentified Alcid 1,146 773 324 205 I

Total Alcids (Family Alcidae) 304,317 139,532· 40,271 12,810

KINGFISHERS I

Belted ki~gfisher (Ceryle a/cyan) 13 16 15 13

PASSERINES I Tree swallow (Tachycineta bic%t') 3 7 0 0

Violet-green swallow (Tachycineta tha/assina) 93 164 0 0

I Bank swallow (Riparia riparia) 310 368 0 0

Unidentified swallow (Tachycineta or Riparia sp.) 101 104 0 0

Gray jay (Perisoreus canadensis) 0 0 2 4

Steller's jay (Cyanceitta stellen) 0 0 2 4

Black·billed magpie (Pica pica) 23 ·28 64 56 I

Northwestern crow (Corvus caurinu$) 243 185 835 742

Common raven (Corvus corax) 43 26 23 22 I Gray-erownecriosy finch (Leucosticte tephrocotis) 0 0 212 404

Pine siskin (caiduelis pinus) 0 0 85 167

Unidentified paSSerine 0 0 159 311

I Uniden@ed bird 1,483 867 714 693

MARINE BIRDS . Total marine birds 798,042 195,555 122,946 25,804 I

I

I

120

I
~'.

'.t,

,

o

372

o

592

221

Winter

151

o

302

o

1,104

402

650

93

284

3,094

,

428

571

48

286

5,914

,

I

. I . t . . Appendix B. Esti 'I,ated population abundance of marine mammals (N ± 95% CI) from

boat surveys of Lower Cook Inlet, Alaska in summer 1993 and winter 1994.

-_---..;--:.-' 1 -----'---------'-----

I

Summer

Species N CI N CI ~--------,-------

CETACEANS 1-, ' Harbor porpoise (Phocoena phocoena)

Dall's porpoise (Phodoenoides dalli) . , . I

Minke whale (Balaenoptera acutorostrata)

OTTERS I·

Sea otter (Enhydra Mrrs)

SEA LIONS .1'

Steller sea.lion (Eumetopias jubatus)

SEALS . I.. ... Harbor seal (Phoca vitulina)' 2,288 1,698 107 105

____-1-1--_-'-- _

c.

I

121
t

Ii•II•

,I)I

•

. I

I.I

jI!

•

!I,i .• !I I i,i •IIII•III
,j

Ii,.' I:

I',". ':

H

'I

"

II

Iii'

'I

,;

'i':.

"

iii

tl:j

.ili:.

'il

:'.

,:1

,I

1,1

"

Appendix C. Op ,olrtunistic sightings of marine mammals observed during boat

. surveY,s,of lLower Cook Inlet,Alaska in summer 1993 and winter 1994.

i ~~

Summer 1993C:>;.;. .

Several ~h ;es were sighted while we were moving between transects. We

had one sighting It' four killer whales (Orcinus orca) near Port Graham, and one

sighting of three ~umPback whales (Megaptera no'veangliae) breaching 20 km north of

the Barren ISlandJ. ' We obtained identification photographs of the killer whales and

have forwarded th1em to the National Marine Mammal Laboratory in Seattle.' We had a

number of minke lhale sightings in Kachemak Bay and along the shoreline north of

Anchor Point.

Winter 1994

Killer whalTwere spotted on two occasions in Kachemak Bay. On 4 February,

a group of three or four killer whales was seen near Yukon Island. On 6 February, a

group of eight to tin killer whales was spotted between 60-foot Rock and the Homer

Spit. One minke lha,e was observed off Anchor Point.

•,

122

\
II

I

I

I

i

, . I

: I ,. ,

I

I

I

I

I

I

I

. I ,

I

,! I

!

i I

I ,

, I

i I
"'=c_' -

'" .."" -'~----" -. "~-""- ~_.~ - ~=_~_"=_='lIii( -·==_..-_-;-==~_-~_-=""iiii~ ..-..

Appendix D. Counts of marine birds and mammals within the 0.2 nm (400 m) zone during an aerial survey of Ihe'Kachemak Bay and western

shorelines of Lower Cook Inlet in winter 1994. Shoreline sections follow Arneson (1980): (3) Anchor Point to Homer Spit tip; (4) Homer • Spit tip to Peterson Bay; (5) Chinapoot Bay to Poinl Bede; (8) Tuxedni Bay; (9) Tuxedni Bay to Chinitna Bay; (10) Chinitna Bay;

(11) Iniskin Peninsula; (12) Oil Bay, Iniskin Bay, and Iliamna Bay; (13) South Head 10 Chenik Head, including Ursus Bay and Bruin Bay;

(14) Amakadedulia Cove, McNeil Gave, and Akumwarvik Bay; and (15) Akumwarvik Bay to Cape Douglas.

Kachemak Bay Shoreline Weslern Shoreline

Species .3' 4 5' 8' 9 10 11 12 13 . 14 15

Marine Birds . " .'jl· 't'l , ... - CommonJoons 0 1 9 0 0 0 0 0 0 0 0_ •. , .- - -~ -- -~-- ---~ " ....... ..- ,-- ••• Unidentified loons 1 5 17 0 0 0 0 0 0 0 1

Loons .1". 1 6 26 0 0 0 0 0 0 0 1

Red-necked grebes 0 1 6 0 0 0 0 0 0 0 0

Grebes 0 1 6 0 0 0 0 0 0 0 0

Cormorants· 6 102 104 0 0 0 0 . 0 0 0 25

Walerfowl 193 2,013 4,319 208 33 456 613 1,205 1,153 97 725

Green-winged teal 0 0 4 0 0 0 0 0 0 0 0

Mallards 0 32 189 40 0 0 0 0 0 0 0

Dabbling ducks 0 32 193. 40 0 0 0 0 0 0 0

Scaup· 0 0 0 0 0 1 0 100 0 0 35

Goldeneyes· 0 431 697. 84 0 0 0 0 0 0 3

Buflleheads 0 74 34 0 0 0 0 .0 0 0 0

Diving ducks 0 505 981 84 0 1 0 100 0 0 38

Common eiders 24 0 41 0 0 0 0 5 0 0 33

Steller's eiders 22 0 420 0 0 0 0 435 928 0 0

Eiders 46 0 461 0 0 0 0 440 928 0 33

HarleqUin ducks 0 0 261 0 0 8 16 48 10 0 191

Oldsquaws 42 49 122 38 0 304 0 397 78 95 243

Black seaters . 105 35 737 0 31. 66 597 183 107 0 193

Surf scalers 0 128 549 0 0 0 0 0 0 0 12

White-winged seaters 0 160 223 8 0 0 0 0 0 0 8

Unidentified seaters 0 0 0 0 0 0 0 0 0 0 6

Scalers' 105 323 1,509 8 31 66 597 183 107 0 219

Sea ducks 193 372 2,353 46 31 378 613 1,068 1,23 95 686

,

123

...
Appendix D (continued).

Kachemak Bay Shoreline Weslern Shoreline

Species 3' 4 5' 6' 9 10 11 i 12 13 14 15

Red-breasted mergansers 0 1,104 792 36 2 77 0 37 30 2 1

Mergansers 0 1,104 792 36 2 77 0 37 30 2 1

Bald eagles 51 10 35 1 0 .0 2 1 0 1 1

Shorebirds· 0 230 0 0 0 200 0 0 0 0 34

Mew gulls 0 1 0 0 0 0 0 .0 0 0 0

Herring gulls 0 26 0 3 0 7 0 1 0 0 0

Glaucous-winged gulls 0 0 10 0 0 0 0 0 0 0 0

Glaucous gulls 1 5 2 1 0 0 0 1 1 0 1

Unidentified gulls 66 516 621 0 0 2 0 30 2 0 2

Gulls 69 550 633 4 0 9 0 32 1 0 3

Alcids -0 6,673 637 2 O. 0 O· 0 0 -0 0

Murres· 0 6,671 633 2 0 0 0 0 0 0 0

Murrelets' 0 2 4 0 0 0 0 0 0 0 0

Northwest crows . 0 50 60 0 0 0 0 0 0 0 0

Common ravens 0 0 0 0 0 0 0 0 0 0 0

Total marine birds' 320 9,635 5,620 215 33 665 615 1,236 1,154 96 769

Marine Mammals

Beluga whales 0 0 0 0 0 0 0 2 0 2 0

- Sea oilers 1 152 130 0 0 0 0 16 76 0 90

Steller sea lions 0 16 1 0 0 0 0 0 0 0 0

Harbor seals 0 4 6 0 0 0 0 9 2 0 53

, Area sUlyeyed was less than Arneson's (1960) original sections.

• .Within these groups, total birds were not identified to species.

, Marbled and Kitllitz's murrelets only. . , Bald eagles and common ravens were nol included in tolal marine birds, thus this column will not add vertically.

124

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