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SEA OT'l:ER SURVEY, KODIAK .ARCHIPELAGO, - 1985

Key Words: Sea otter Alaska Distribution · Abundance

lMarine Mammal Management Project Wildlife Assistance U.S. Fish and Wildlife Service lOll East Tudor Road Aochorag~, Alaska 99503

2 Kodiak National Wildlife Refuge U.S. Fish and Wildlife Service P.O. Box 825 Kodiak, Alaska 99615 i

March 1986 INTRODUCTION

Historical records indicate that sea otters (Enhydra lutris) were abundant prior to intensive commercial exploitation (1742- 1911). However, by the end of the 19th century sea otters were nearly extinct. By 1911, when sea otters were given complete protection by Federal statute, the populations had been reduced to a few animals at 13 known, but widely separated, sites in the eastern North Pacific (Kenyon 1969). Many of these remnant populations have steadily grown and expanded their ranges. (In some areas this came about through re-introductions.) For the past 30 years the pattern of repopulation of former habitat by sea otters has been monitored by the United States Fish and·Wildlife Service (USFWS) and the Alaska Department of Fish and Game (ADFG) through a series of surveys (Lensink 1960; Kenyon 1969; Schneider 1976). Today, many subpopulations are probably at or above historic levels.

Increases in subpopulations of sea otters, range expansion into areas also used by humans, and their ability to greatly reduce locally abundant shellfisheries (Ebert 1968; Estes et al. 1978) are causing a growing concern among recreational, commercial, and subsistence users of shellfish in some areas. The Kodiak Archipelago is one of these areas. As the sea otter popHlation increases, problems are expected to arise where human populations are utilizing shellfish resources which otters prey upon. Until recently, sea otters have been absent or at low densities in the vicinity of human populations in Alaska. This situation has now changed. Left unresolved, the problem of high numbers of sea otters (in some subpopulations) will intensify competition between sea otters and hu~an shellfish users. A heightened animosity toward sea otters will lead to increased illegal killing.

The 1972 Marine Mammal-Protection Act (MMPA) placed the authority and management responsibility for sea otters under the USFWS. However, the Act presently restricts the Service from "active management" of sea otter populations without first undertaking complicated waiver proceedings. The provisions of the Act do not apply however to the non-wasteful taking of marine mammals by any coastal Alaska Native (for the purposes of subsistence or creating and selling authentic Native handicrafts and clothing). Conceivably, entire populations of sea otters in localized areas could disappear under this "no management" regime. A comprehensive and enforceable management plan is needed to ensure sustainable populations of sea otters over historic ranges.

A need exists along the Kodiak Archipelago for increased knowledge of the ecology, distribution, and abundance of sea otters. Competition with commercial fisheries by sea otters has been a problem in the past, can be expected to continue, and will probably increase in the future whether or not human utilization of fish and shellfish resources increases.

There has never been a complete survey of sea otter range in Alaska, even after the MMPA was passed in 1972. Limited information from studies in specific areas and casual observational data support the conclusion that sea otters are increasing in recently occupied areas, that there are some sea otters in all of the historic Alaskan range, and, except for southeast Alaska, populations are likely to be, within this decade if not already, at or near carrying capacity ·(Johnson 1982).

1 The objectives of this survey were to obtain current information on the. distribution and relative abundance of the Kodiak Archipelago population, and to identify changes that have occurred since the 1984 survey (Simon-Jackson et al. 1985). This information can be used for predicting future changes likely to cause increasing conflicts with management of important fisheries resources. It will also be used to assist the Service in recommending a management program for sea otters.

METHODS

The survey was conducted along the coastline, islands, and offshore rocks of Shuyak, , and the northern coast of Kodiak Island in the Kodiak Arehipelago. The southern end of Kodiak Island was not surveyed du~ to time constraints and the fact that few observations of sea otters have been reported in the area.

Surveys were conducted on 12 and 17 September 1985 (T. Simon-Jackson: observer, M. Vivian: pilot) along Raspberry and Afognak Islands; on 23 September 1985 (D. Zwiefelhofer: observer, M. Vivian: pilot) along Kupreanof Strait and the north side of Kodiak Island from Viekoda Bay to Kodiak; and on 25 September 1985 (D. Zwiefelhofer: observer, M. Vivian: pilot) around Shuyak Island, Latax Rocks, and Sea Otter Island. The surveys were flown using a float-equipped single engine, fixed-winged Piper Super Cub aircraft. The surveys were flown at an altitude of 500 feet (152 m) and an airspeed of 85 mph (74 knots), The plane was flown parallel to the shoreline far enough from shore.to provide a good viewing area on both sides of the aircraft, but close enough to readily distinguish otters nearshore. In areas where sea otters scatter over large shallow offshore areas, the plane was flown in a zig-zag pattern over the potential sea otter habitat. Observations were made by both the observer and the pilot. The number and location of otters were recorded by the observer on a map •. All pods of otters greater than 30 were photographed using a 35mm camera, 85-205mm zoom lens, and ASA 400 Ektachrome color slide film for later verification of accuracy of ocular counts.

The surveys were only flown when the weather was considered suitable (i.e·. sunny or high overcast, calm waters, and little or no wind). Waters were calm in bays and passages except for slight ripples to light chop on exposed points and shorelines. Gusts and swells were encountered along Seal Islands, Vantage Rock, and Tolstoi Point on Afognak Island. Overall, the weather and visibility were good while surveying.

The aerial survey was particularly difficult to complete. In addition to storms, periods of high winds and low ceilings prevented flying. Marine weather patterns for the Kodiak Archipelago during the survey period are given in Table 1. The survey was an attempt to duplicate the survey flown in 1984 I (Simon-Jackson et al. 1985) at approximately the same time of year, but was not completed because of adverse weather conditions (Figure 1, Table 2). We were unable to survey the coastlines of Afognak Island (from Tonk! Bay to Kazakof Bay) and Marmot Island ,due to poor surveying weather. The effect of weather conditions on sea otter distribution and abundance in the Kodiak area is largely speculative at this time.

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Table 1. Local climatological data for Kodiak, Alaska for the month of September, 1985 (U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Weather Service, WS Form F-6).

Day Tem;eerature Precipitation Wind Maximum Minimum (inches) Speed (mph) Peak Gust (mph) Dir.

1 60 48 0 20 25 NW 2 58 42 0 14 22 w 3 53 47 0 12 14 E 4 65 48 0 16 23 NW 5 70 47 0 16 20 NW 6 68 45 0 16 23 lv 7 67 44 0 18 28 sw 8 60 49 0 13 21 NW 9 59 41 0 15 22 NW 10 58 44 0 24 39 NW 11 58 39 0 13 22 NW 12* 54 39 0 12 20 s 13 63 50 0 21 28 sw 14 73 56 0 23 37 sw 15 61 48 0 30 46 w 16 56 45 0 37 51 NW 17* 55 39 0 18 23 w 18 56 45 0 22 31 s 19 56 43 0 31 47 NW 20 55 38 0 26 35 NW 21 50 38 0 30 39 E 22 58 44 0 28 44 E 23* 60 40 0 16 24 sw 24 57 39 0 17 31 NW 25* 52 32 0 13 17 SE 26 56. 47 0 30 40 SE 27 58 43 0 30 36 SE 28 53 38 0 38 46 SE 29 57 43 0 31 52 SE 30 55 41 0 12 18 NW

* Date of aerial survey

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3 Figure 1. Comparison of the distribution and relative abundance of sea otters along the Kodiak Archipelago, 1975-76/1984/1985.

#/#/# = numbers observed 1975/numbers observed 1984/numbers observed 1985 -/#/- = area not surveyed in 1975 or 1985

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4 Table 2. Distribution, relative abundance, and group size of sea otters along the Kodiak Archipelago, 1985.

Survey Area No. Seen Group Size

Uyak Bay Harvester Island Spiridon Bay Chi~f Pt. to Twocone Pt. Miners Pt. Uganik Passage Viekoda Bay 68 13,14,14,17 Kupreanof Strait 322 3,3,3,4,4,4,4,5,5,6,6,6,6,7,10,12,12, 12,15,26,55,56 Whale Passage 32 30 Afognak Strait 228 3,3,4,4,5,6,9,15,19,50,80 Whale Island 106 5,10,31,49 Kizhuyak Bay 3 Triplets Island 14 5,9 Wooded Island 94 20,34,38 Spruce Island 10 3 Hog Island 103 10,92 Afognak Bay 160 3,3,4,4,8,8,26,41 Kazakof Bay Duck· Bay Cape Izhut to Peril Cape Izhut Bay King Cove Pillar Cape toward Tonki Cape Marmot Island Tonki Cape Tonki Bay Seal Bay 327 3,3,3,3,3,3,3,3,4,4,6,6,7,8,12,16,17, 20,20,26,40,60 Perenosa Bay 194 3,3,3,3,3,4,4,5,6,6,8,8,40 Shuyak (east) 77 3,3,5,6,32 Sea Otter Island 49 3,4,10,12,14 Point Bay 4 Shuyak (north) 103 3,3,3,3,4,5,5,13,18,22 Latax Rocks 66 4,6,51 Shuyak (west) 221 3,3,3,3,3,4,4,4,4,5,6,6,6,9,10,16,80 Shuyak Strait 31 4 Bluefo:x: Bay 303 3,3,5,5,6,7,8,10,18,30,30,45,87 Foul Bay 60 3,3,3,4,4,5,5 Paramanof Bay 104 3,3,3,4,5,5,5,5,6,8,8,9 I Malina Bay 36 3,6 Raspberry Strait 93 3,5,6,6,7,9,10,15 Raspberry Cape 3 3

Total Otters Seen 2811

5 The activity of animals can have a pronounced effect on the numbers seen. Counts made when animals are resting in pods are usually higher than when animals are scattered and feeding (Schneider 1971; Pitcher 1975). Weather conditions, both during the count and for several days before the count (see Table 1), and time of day can influence distribution.

All surveys were conducted between the hours of 0900 and 1630 ADT or local time. According to Garshelis (1980), most otters can be found resting between 0800 and 1400 and in transition from resting to feeding from 1400-1700. Otters were not surveyed during periods when they would most likely be feeding (1700-0600), or in transition from feeding to resting (0600-0800). During the surveys, when active feeding began, the survey was. terminated for the day.

Sea otters were seen hauled-out on rocks in several locations: Raspberry Strait, Foul Bay, Vantage Rock, and Tolstoi Point. Hauled-out sea otters were generally difficult to see. Their dark coats blend with the dark mats of algae on rocks and their lighter heads with the white and tan granite/feldspar rocks or clumps of goose barnacles protruding from the seaweed. Sea otters must often move before they are seen in these instances.

RESULTS AND DISCUSSION

A total of 2,811 sea otters was observed. Observations of individuals and groups were recorded and mapped (Table 2 and Figure 1). Specific locations were also mapped (on file- Region 7 RO). Direct comparison of the overall results with those of the 1975/76 and 1984 surveys (Simon-Jackson et al. 1985). is not possible as the surveys do not cover the same area (due to adverse weather conditions). However, some trends in specific areas may still be apparent (i.e~, changes in distribution, abandonment of areas, etc.).

Group sightings are considered to be local population centers. Areas supporting large populations are: Kupreanof St·rait, Bluefox Bay, Shuyak (west), Seal Bay, Afognak Strait-Whale Island-Marmot Bay (Figure 1, Table 2).

A comparison of the 1985 survey results with the 1984 survey results reveals di££erences in distribution and relative abundance (Figure 1, Table 3). Observations of sea otters totalled 2,811 animals in the 1985 survey compared to a total count o£ 2,662 animals for the same area in the 1984 survey. Differences in distribution appeared between the two surveys with apparent changes in population centers (Figure 1). In the 1984 survey population centers appeared to be located at Kupreanof Strait, Raspberry Strait, Bluefox Bay, Shuyak (west), Latax Rocks, Shuyak (north), and Sea Otter Island (Figure 1, Table 3). In the 1985 survey numbers are comparatively lower for Raspberry Strait, Latax Rocks, Shuyak (north) and Sea Otter Island. Numbers for Perenosa Bay and Seal Bay were higher in the 1985 survey than the 1984 survey, but still don't approach the counts for the 1975-76 survey. Numbers are obviously higher in the Afognak Strait-Whale Island-Marmot Bay area (7 in 1975-76, 106 in 1984, 750 in 1985). Because we were unable to survey the east side of Afognak Island, it is difficult to predict where these sea otters came from. However, we believe they moved into the area through Raspberry and Kupreanof Straits either as a result of normal dispersal patterns or because of Native hunting pressure. Over the past few years, Native take of sea

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Table 3. Comparison of survey results for sea otters for portions of the Kodiak Archipelago.

1975 1976 1984 1985 Study Area Date No. Ottersl Date No. Otters2 Date No. Otters3 Date No. Otters4

Uyak Bay 2/11 1 10/16 1 Spiridon Bay 10/16 9 Harvester Island 10/16 1 Chief Pt. to Two cone Pt. 10/16 22 Cape Ugat 12/10 1 Miners Pt. 2/10 1 10/16 1 Uganik Passage 2/10 37 10/16 25 Viekoda Bay 10/15 156 9/23 68 Kupreanof Strait 2/3 1 9/11,10/15 430 9/23 322 Whale Passage 10/15 7 9/17 32 Afognak Strait 10/15 6 9/17 228 Whale Island 10/15 1 9/17 106 Kizhuyak Bay 10/15 8 9/23 3 Triplets Island 10/15 45 9/17 14 Wooded Island 10/15 7 9/17 94 Spruce Island 10/15 31 9/17 10 Hog Island 2/'l 1 9/11 1 9/17 103 Kodiak area 2/9 0 10/15 0 9/23 0 Afognak Bay 10/6 6 9/11 0 9/17 160 Kazakof Bay 10/6 0 9/11 6 Duck Bay 10/6 1 9/11 69

Continued

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Table 3. Continued

1975 1976 1984 1985 Survey Area Date No. Ottersl Date No. Otters2 Date No. Otters3 Date No. Otters4

Cape Izhut to Peril Cape 9/11 59. Izhut Bay 10/6 1 9/11 8 King Cove 10/7 9/11 0 Pillar Cape to Tonki Cape 10/7 16 9/11 28 Marmot Island 10/7 529 9/11 28 Tonki Cape 10/7 134 9/11 1 Tonld Bay 10/7 32 9/11 27 Seal Bay 10/7 506 9/11 104 9/17 327 00 Perenosa Bay 10/7 348 9/11 100 9/12 194 Shuyak (east) 10/7. 10 9/12 62 9/25 77 Sea Otter Island 10/7 156 9/12 231 9/25 49 Point Bank 10/7 9 9/12 16 9/25 4 Shuyak (north) 10/7 14 9/12 250 9/25 103 Latax Rocks 10/7 59 9/12 277 9/25 66 Shuyak (west) 10/7 12 2/5 272 9/12 304 9/25 221 Shuyak Strait 10/7 2 2/4 14 9/12 46 9/12 31 Bluefox Bay 10/7 81 2/4 32 9/11 167 9/12 303 Foul Bay 10/7 61 .2/4 60 9/11 54 9/12 60 Paramanof Bay 2/4 15 9/11 9 9/12 104 Malina Bay 9/11 91 9/12 36 Raspberry Strait 9/11 213 9/12 93 Raspberry Cape 9/11 46 9/23 3

TOTAL 1977 435 2947 2811 ~

1 Results o~ helicopter survey conducted by ADFG (Schneider 1976) 2 Results of boat survey conducted by ADFG (Schneider 1976) 3 Results of fixed-winged aerial survey conducted by USFWS (Simon-Jackson et al. 1985) 4 Results of fixed-winged aerial survey conducted by USFWS (Simon-Jackson et al. 1986) otters has increased in these areas (pers. comm., local residents and Native hunters). Behavioral changes (diving and porpoising in response to boats and aircraft) have been noted over the last two years within the populations of sea otters which inhabit these two Straits. It is possible these populations are adjusting their behavior to local hunting pressure by Natives.

Range expansion (within suitable habitat) southward from Afognak Island is still apparently occurring. It is difficult to determine with this data alone, if the shifts in distribution represent changes in seasonal distribution, range extensions, normal variation within the distribution of groups of otters, or variation resulting from differences in survey conditions, observers, pilots, etc. representing no actual change in distribution. ·

The effectiveness of surveys of the type used in this project can be highly variable. The results should be interpreted with due consideration to the survey conditions and completeness of coverage. The probability of sighting a sea otter is influenced by the speed, altitude and type of aircraft; distance from the trackline; observer experience and ability; time of day; lighting conditions; sea state; weather conditions; activity of the animal; group size; and presence of birds, other marine mammals, kelp, etc. Any and all of these can effectively reduce the reliability of counts. Some success has been achieved in sea otter censusing through intensive use of combinations of air and ground counts over small areas and at high costs. The results indicate that there may be 1.5 to 4 times as many sea otters as are seen from a helicopter and perhaps 4 to 10 times as many as seen from a fixed-winged aircraft, but it has never been possible to measure all variables (Schneider 1976). Kenyon and Spencer (1960) assumed that nearly 25% of the otters in the flight path will be submerged and missed during a survey. Estes and Smith (1973) stated that during periods of minimum feeding activity approximately 30% of a population will be underwater at a given instant. Therefore, the counts presented in this report should be considered minimum. The numbers indicate distribution and relative abundance and permit only rough estimates of population size. However, with several year's of replicate surveys, the technique may provide a useful and relatively reliable population index.

SUMMARY

This sea otter survey was aimed at obtaining an index to abundance (which would sho~either localized changes in distribution or abundance over a large area). There was no attempt to estimate the absolute size of the populatiqn from this survey. The data being compared were collected for purposes of comparison. Surveys are valuable for year-to-year comparisons of density, for determination of habitat preference, or (when correction factors are applied) for providing minimum estimates of abundance.

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RECOMMENDATIONS

Additional monitoring of sea otter distribution seasonally is needed to determine whether or not observed shifts in distribution indeed·represent range expansion or simply changes in seasonal distribution or normal variation within the distribution of groups of otters.

Further research on the effects of otters on their environment along the Kodiak Archipelago is needed to understand sea otter/fisheries interactions and perceived conflicts.

Lastly, a comprehensive and enforceable management plan is needed to ensure sustainable populations of sea otters over their historic range along the Kodiak Archipelago. This plan would include monitoring the Native harvest, determining incidental take in fisheries gear, and determining the carrying capacity of the habitat to support sea otters.

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10 LITERATURE CITED

Ebert, E. E. 1968·. A food habits study of the southern sea otter, Enhydra lutris nereis. Calif. Fish and Game. 54:33-42. Estes, J. A. and N. S. Smith. 1973. Research on the sea otter, Island, Alaska. Final Rept. USAEC. NV0-520-l. 85pp. Estes, J. A., N. S. Smith, and J. F. Palmisano. 1978. Sea otter predation and community organization in the western , Alaska. Ecology 59:822-833.

Garshelis, D. L. 1980. Sea otter predation on shellfish in Prince William Sound, Alaska. Unpubl. proposal.

Johnson, A. M. 1982. Status of Alaska sea otter populations and developing conflicts with fisheries. Forty-Seventh North American Wildlife Conference. pp. 293-299.

Kenyon, K. w. 1969. The sea otter in the eastern Pacific Ocean. USFWS. North American Fauna No. 68. 352 pp. Kenyon, K. w. and D. L. Spencer. 1960. Sea otter populations and transplant studies in Alaska, 1959. USFWS, Spec. Sci. Rept. Wildl. No. 48:1-29.

Lensink, C. 1960. Status and distribution of sea otters in Alaska. J. Mammal. 41(2) :172-182.

Pitcher, K. W. 1975. Distribution and abundance of sea otters, Steller sea lions, and harbor seals in Prince William Sound, Alaska. ADF&G. Unpubl. ·rept.

Schneider, K. B. 1971. An evaluation of sea otter survey techniques. ADF&G. Unpubl. rept. Schneider, K. B. 1976. Assessment of the distribution and abundance of sea otters along the Kenai Peninsula, Kamishak Bay, and the Kodiak Archipelago. ADF&G Report. Contract No. 03-5-022-69. 72pp. Simon-Jackson, T., D. Taylor, S. Schliebe, and M. Vivian. 1985. Sea otter survey, Kodiak Island - 1984. USFWS rept. lOpp.

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