TABLE OF CONTENTS
Study No. G-I INVENTORY AND CATALOGING PAGE
Job No. G-I-I Inventory and Cataloging of Arctic Area Waters By: Terrence N. Bendock
Abstract .••••. 1 Key Words 2 Background • 2 Recommendations ..•• 5 Research . 5 Management •. •• ..••.•.. 5 Objectives •..••..•••.. 5 Techniques Used .••••.• 5 Lake Surveys. ....•••• 5 Mountain Lakes •••..•••••..•••. 6 Winter Sampling 6 Radio Telemetry 6 Findings ..•. 7 Lake Surveys .•••• 7 Mountain Lakes . 7 Tulugak Lake .••.•• 7 Irgnyivik Lake • 9 "Lower Anayak Lake". • ••• 9 Natvakruak Lake .•••....•.••.•. 9 Coastal Plain Lakes .••• • • 10 Life History Discussions of Coastal Plain Species .. .. . 10 Least Cisco .•••• .•••. . • • 13 Broad Whitefish .•••• .••.••.•• • 13 Lake Trout ...... 17 Other Species .•••.••• • • 17 Winter Char Habitats In the Anaktuvuk River•. • 20 Tagging Site Characteristics .•• • • 21 Winter Movements •••.•••••••• • • 23 ,Overwintering Habitat and Sampling •••••.•.•...... 28 Additional Sampling of Spring Areas •••••.• · 33 Segregation of Fish. ••• •.•. 33 Radio Telemetry of Char in the Sagavanirktok River Drainage • 33 Arctic Char Aerial Counts. •• •.••...• • 36 Experimental Fish Stocking - Pt. Barrow. 36 Dalton Highway •.•• 40 Literature Cited .•.•••• •• 42
LIST OF TABLES AND FIGURES
Table 1. Fish species found along the haul road and North Slope•. 3 Figure 1. State of Alaska showing the North Slope and locations of studies for 1981 • . • . • • . • • • • . . . 4 Figure 2. Map of Anaktuvuk Pass showing locations of four mountain lakes surveyed during 1981 •.•. • . • • . • . . • 8 ARLIS Alaska Resources .ces .& Information SerVl Library ~dl Alaska Anchor<- Figure 3. Coastal Plain Province of North Slope showing locations of lakes surveyed during 1981 . . . . • . . • .. 11 Table 2. Locations. physical characteristics and species captured in 19 coastal plain lakes during 1981 .••..•..•. 12 Figure 4. Length frequency of 107 least Cisco captured in Arctic coastal plain lakes ••••••..•• ...... • 14 Figure 5. Back-calculated fork lengths of least cisco taken in C-62 Lake (coastal plain lake). Prudhoe Bay and Chatanika .1 River (interior Alaska) .••.••.• .• .•... 15 Figure 6. Length frequency of 66 broad whitefish captured in Arctic coastal plain lakes •••.•.••.•...• 16 Figure 7. Back-calculated fork lengths of broad whitefish taken in coastal plain lakes. Prudhoe Bay and Minto Flats (interior Alaska) .•. •• ••.•....•..• 18 Figure 8. Length frequency of 26 lake trout captured in Arctic coastal plain lakes ••..••.••...•.•. .. 19 Figure 9. Anaktuvuk River showing the location of capture and release of twelve radio-tagged Arctic Char. 1980-1981 .• 22 Figure 10. Location of tagging sites in Anaktuvuk River. September. 1980 • • • • • • . • . • . • . . • 24 Figure 11. April distribution of tagged Arctic Char. seven months after release •••••••.••.•..•.. . 24 Table 3. Fork length. weight. sex and spawning conditions of twelve char radio-tagged in the Anaktuvuk River. 1980 ..... 25 Table 4. Number of tags functioning on each radio tracking date. 26 Table 5. Distance travelled by radio tagged Arctic char in the Anaktuvuk River between 9/21/80 and 4/1/81 . 27 Figure 12. Anaktuvuk River overwintering site and sampling locations. April. 1981 .•••.••••••••.••.•..•.• 29 Table 6. Physical and chemical characteristics of three sampling sites in the Anaktuvuk River April. 1981 • 30 Figure 13. Schematic drawing of snow. ice and water depths at three Anaktuvuk River sampling sites April. 1981 .. 31 Table 7. Species. and numbers of fish captured at three overwintering sites in the Anaktuvuk River. 1981 · 32 Table 8. Site characteristics and species present in four spring areas in the Anaktuvuk River drainage April. 1981 • 34 Figure 14. Locations of Radio-Tagged Arctic Char in the Sagavanirktok River Drainage. September. 1981 .. 35 Table 9. Physical characteristics of tagging sites and Arctic char radio tagged in the Sagavanirktok River drainage. 1981 .. 37 Table 10. Aerial estimates of anadromous char in index areas of the Sagavanirktok and Anaktuvuk Rivers. 1971-1981 .. 38 Figure 15. Isatkoak Lagoon Complex at Point Barrow. Alaska 39 Table 11. Late winter dissolved oxygen values obtained at Isatkoak Lagoon . 0••••••••••• " •••••••• 41 Table 12. Water quality values obtained from Isatkoak Lagoon in July. 1980 ••••••.••••••..••..•..• 41 ii TABLE OF CONTENTS (Cont'd.) Study No. G-I INVENTORY AND CATALOGING PAGE Job No. G-I-P-A Inventory and Cataloging of Sport Fish and Sport Fish Waters of Western Alaska By: Alfred DeCicco Abstract . 44 Scope .••. 45 Key Words 45 Background . •.••• •••. 45 Recommendations ..•.•••••••• 46 Research . •••..••• 46 Management .•••. 48 Objectives •• . •.••••••••• 48 Study Area . .••••• 48 Techniques .. ••••••• ••• 48 Findings ...... 51 Movements of Spawners 51 Overwintering Movements .•••• 53 Spawning ...... 54 Overwintering ••••• 57 Observations of Juvenile Char 59 Biological Aspects • 59 Utilization .••• 65 Literature Cited ..• 65 LIST OF TABLES AND FIGURES Table l. List of common names, scientific names and abbreviations of fish found in study area 47 Figure l. Study Area 49 Table 2. Number of char···tagged···in· the study area by year, sex, type and location 52 Table 3. Aerial observation of····spawning· char in the Noatak drainage 55 Figure 2. Known spawning· ·· and overwintering····· · · areas in the···Noatak· system . . . 56 Figure 3. Known spawning· ·· and overwintering· · · · · · · areas in· ····the Wulik,· Kivalina and Omikviorok Rivers · 58 Table 4. Char smolts captured on the lower Noatak,··June·· 14, 1981. . 60 Table 5. Gill raker counts . 60 Table 6. Sex ratio of Arctic char spawners··· · ·in····Noatak··River·· tributaries 61 Table 7. Length frequency· ··of·Noatak··· River·· · spawners·····and· ·· Kivalina River overwintering char by sex 61 Figure 4. Length frequency by sex of char tagged in···the Noatak system . 62 Table 8. Ova counts· of· ···20 female· · ·Arctic··· char· · ·····ovaries from·· the Noatak River drainage ·· · · · ···· · ··· 64 iii TABLE OF CONTENTS (Cont'd.) Study No. G-I INVENTORY AND CATALOGING PAGE Job No. G-I-P-B Inventory and Cataloging of Sport Fish and Sport Fish Waters of Western Alaska By: Kenneth T. Alt Abstract . 67 Key Words 68 Background . 68 Recommendations ..•• 68 Research .. 68 Management •. 71 Objectives 71 Techniques Used. 71 Findings ...•.• 72 Innoko River Study •..•.. 72 Sheefish Adaptability Study 76 1981 Sheefish Stocking . 76 Evaluation of new waters for stocking. 78 Literature Cited ••.•• 79 LIST OF TABLES AND FIGURES Figure l. Innoko River study area ...... 69 Table i . List of common names, scientific··· · names,· · · ·and abbreviations of fish found in study area .. .. 70 Table 2. Test net results in the Innoko River and tributaries, 1981 .. . 73 Table 3. Sex and maturity of Sheefish·· captured· · · · ··in the Innoko River, 1981 . · · · · ·· ·· 74 iv Volume 23 Study No. G-I-I STATE OF ALASKA Jay S. Hammond, Governor Annual Performance Report for INVENTORY AND CATALOGING OF ARCTIC AREA WATERS by Terrence N. Bendock ALASKA DEPARTMENT OF FISH AND GAME Ronald O. Skoog, Commissioner DIVISION OF SPORT FISH Richard Logan, Director Volume 23 Study No. G-I RESEARCH PROJECT SEGMENT State: ALASKA Name: Sport Fish Investigations of Alaska Project No.: F-9-14 Study No.: G-I Study Title: INVENTORY AND CATALOGING Job No.: G-I-I Job Title: Inventory and Cataloging of Arctic Area Waters Cooperator: Terrence N. Bendock Period Covered: July 1, 1981 to June 30, 1982 ABSTRACT This report presents baseline fisheries information on 23 lake surveys conducted on the North Slope, overwintering habitats of Arctic char, Salvelinus alpinus (Linnaeus) in the Anaktuvuk River, aerial index counts of char in the Sagavanirktok and Anaktuvuk River drainages, an experimental stocking of grayling Thymallus arcticus (Pallas) at Pt. Barrow and angling effort along the Dalton Highway. Lake surveys were conducted on four mountain, and 19 coastal plain lakes during 1981. Seventeen (74%) of the waters investigated contained fish. Least cisco, Coregonus sardinella Valenciennes, and lake trout, Salvelinus namaycush (Walbaum), were the most frequently encountered species. A brief life history discussion of the predominant species is presented. Radio telemetry was used to monitor the winter movements of 12 Arctic char in the Anaktuvuk River. Tagged char, under the Anaktuvuk River ice, were essentially sedentary for a period of time exceeding 8 months. There was some evidence that fish segregated by species and size within spring areas during the winter months. A description of the overwintering habitat is presented. Aerial index counts of Arctic char in the Anaktuvuk and Sagavanirktok Rivers were conducted. Values obtained during the surveys compared favorably with previous estimates. A freshwater lagoon at Pt. Barrow was investigated and approved for stocking with 50,000 grayling fry. An evaluation of the success of this stocking has not been completed at this time. Sport fishing pressure along the Dalton Highway was monitored during the summer of 1981. Sport fishing pressure north of the Yukon River was light, and concentrated near Alyeska Pump Stations. Unrestricted public access to the first 150 mi of highway north of the Yukon River did not appreciably affect sport fishing pressure and harvest. KEY WORDS Arctic char, Salvelinus alpinus (Linnaeus), interior Alaska, Anaktuvuk River, Arctic Grayling, Thymallus arcticus (Pallas), char tagging, winter movements, fishing pressure. BACKGROUND The Alaska Department of Fish and Game, Sport Fish Division, has conducted fisheries investigations on the North Slope since 1968. Emphasis of this work has varied between drainages and species in an effort to meet the changing patterns of use and activities within this region. Construction of the Dalton Highway (North Slope haul road) has tied the North Slope into the existing state highway system. Improved access has increased the demand for sport fishing, as well as other recreational, municipal, and commercial endeavors in this remote region of the state. Petroleum exploration and development is the overriding force that is shaping the future on the North Slope; municipalities are viewing the newly-found state oil wealth as the key to funding capital improvement projects with costs that have long been out of reach. Many of these activities place increasing demands on the aquatic resources of the region and point to the need for more knowledge of the fish species inhabiting North Slope waters. The Alaska National Interest Lands Conservation Act, in 1980, withdrew vast areas of the North Slope into the National Wildlife Refuge, National Park, and National Wild and Scenic Rivers systems which has heightened the area's scenic and wildlife values with a supplicatory advertising campaign. The report findings for this study are presented in five sections, each treated as a separate phase of the proj ect. The first section describes lake surveys conducted in both mountain and coastal plain waters of the North Slope. In a continuing effort to inventory the region's fresh water fish resources, four mountain lakes and 19 coastal plain lakes were surveyed. A brief life history discussion of the maj or species found in coastal plain waters follows in this section. Section two describes winter habitats and movements of Anaktuvuk River Arctic char based on a study using radio-telemetry to track fish movements under the ice. To confirm these results and describe additional overwinter char habitats, 16 Arctic char were radio-tagged in four tributaries to the Sagavanirktok River during 1981. Additional sections include discussions of Arctic char aerial surveys, an experimental lake stocking near Pt. Barrow and sport fishing pressure along the Dalton Highway. Table 1 lists the species of fish inhabiting waters of the North Slope and found along the highway north of the Yukon River. A map of the study area is shown in Fig. 1. 2 Table 1. Fish species found along the haul road and North Slope. Common Name Scientific Name and Author Abbreviation Alaska blackfish Dallia pectoralis (Bean) AB Arctic char Salvelinus alpinus (Linnaeus) AC Arctic cisco Coregonus autumnalis (Pallas) ACI Arctic grayling Thymallus arcticus (Pallas) GR Broad whitefish Coregonus nasus (Pallas) BWF Burbot Lota Iota (Linnaeus) BB Chum salmon Oncorhynchus keta (Walbaum) CS Fourhorn sculpin Myoxocephalus quadricornis (Linnaeus) FSC Humpback whitefish Coregonus pidschian (Gmelin) HWF Chinook salmon Oncorhynchus tshawytscha (Walbaum) KS Lake trout Salvelinus namaycush (Walbaum) LT Least cisco Coregonus sardinella Valenciennes LCI Longnose sucker Catostomus catostomus Forster LNS Ninespine stickleback Pungitius pungitius (Linnaeus) NSB Northern pike Esox lucius Linnaeus NP Pink salmon Oncorhynchus gorbuscha (Walbaum) PS Round whitefish Prosopium cylindraceum (Pallas) RWF Sheefish Stenodus leucichthys (Guldenstadt)" SF Slimy sculpin Cottus cognatus Richardson SSC 3 172° 164° 66° 70° ./" ,- / / ,/ \ ,/ ,/ ,/ .., ... C\..~ ~ " ..,'" (,,~ .\- .., ... i'c ~~C 4:" .:« . 62° I Point Barrow --- \ 66° "-- 2 Anaktuvuk River \ 'tt'fairbanks Sagavanirktok River \ 3 \ 4 Haul Road \ 5 Coastal Plain Lake Surveys . 58° 62° ., . \ 54° Figure 1. State of Alaska showing the North Slope and locations of studies for 1981. RECOMMENDATIONS Research 1. Lake and stream surveys should continue on North Slope waters with emphasis on NPR-A and coastal plain lakes. 2. Assessment of overwintering fish habitats in North Slope waters should continue with emphasis on spring-fed systems and the Sagavanirktok River. 3. Evaluation of grayling stocked at Pt. Barrow should continue. 4. Fall aerial surveys of Arctic char in the Sagavanirktok and Anaktuvuk Rivers should continue. Management 1. Assessment of the fishing potential of area waters adjacent to the Dalton Highway should continue. 2. Sport fishing pressure on area waters should be monitored. OBJECTIVES 1. To conduct fall aerial surveys of selected waters on the North Slope to determine locations and estimate the abundance of Arctic char stocks with emphasis on the Sagavanirktok and Colville river drainages. 2. To continue monitoring sport fishing pressure on selected waters of the North Slope with emphasis on the North Slope haul road corridor. 3. To determine the availability and use of overwintering fish habitat in lakes and streams of the North Slope with emphasis on the Sagavanirktok and Colville river drainages. 4. To continue inventory and cataloging of potential sport fish waters on the North Slope. 5. To provide recommendations for the management of sport fish resources of the job area. TECHNIQUES USED Lake Surveys A float-equipped Cessna 185 aircraft was used to transport field crews and equipment to remote lakes within the study area. 5 Physiographic data, as well as latitude and longitude, were calculated from 1956 U. S. Geological Survey (USGS) 1: 250 ,000 maps and sectional aeronautical charts. Water chemistry data were measured using a Hach AL-36B field test kit. Water depths were determined with a Lowrance fathometer, and a standard 10-in Secchi disc was used for water clarity. Multifilament and monofiliment graduated mesh sinking or floating gill nets, measuring 125 x 6 ft and consisting of five 25-ft panels of 1/2-in through 2-l/2-in bar mesh, were used to capture fish. Other sampling gear included 25 x 4-ft beach seines, and 25 x 6 ft x l/2-in mesh multifilament gill nets. Hook and line sampling was used to capture burbot and Arctic char. All data were recorded on standard Alaska Department of Fish and Game stream and lake survey forms. All fish samples were grouped by date and location. Weights were recorded to the nearest gram using a ChatLl.Lon spring scale. Fork lengths were measured to the nearest millimeter, and sex and stage of maturity were determined by examining gonads. Ages of Arctic char, lake trout and burbot were determined from otoliths wetted in glycerine and alcohol and viewed under a binocular microscope. All other fish were aged by reading scales. Scales were cleaned and impressed on 20 mil acetate sheets. A Bruning 200 microprojector was used to read scales. Winter Sampling Locations of overwintering char in the Anaktuvuk River were determined using radio-telemetry. Ski-equipped aircraft were then used to transport personnel and equipment to these sites during the sampling period. Ice, water and snow depths were measured to the nearest inch. Dissolved oxygen levels were measured using a Hach AL-36B field test kit and the low range titration procedure. Holes were drilled through ice using a gasoline-powered portable digger with a 10-in bit. Monofilament graduated mesh sinking gill nets, measuring 125 x 6 ft (or individual 50 ft and 25 ft panels from these nets), were used to capture fish under the ice. A "Murphy Stick" (Bendock, 1980) was used to string net lines under the Anaktuvuk River ice. Angling was used to capture both char and lake trout under the ice and a 25 ft x 4 ft beach seine was used to capture fish in open-water spring areas. Radio Telemetry Sixteen Telonics RB-5 radio transmitters were inserted into the stomachs of Arctic char captured in four tributaries to the Sagavanirktok River. The implant and tracking procedures are discussed in Bendock (1981). 6 FINDINGS Lake Surveys During the report period, fisheries surveys were conducted on four mountain lakes and 19 coastal lakes. Surveys were brief, but included information on size, maximum depth, water chemistry and species present. A single experimental gill net was fished overnight in each of the lakes. Life history discussions, following the survey descriptions, refer only to fish captured in the coastal plain. Mountain Lakes Most of the large mountain lakes, lying north of the Brooks Range divide, have had preliminary fisheries surveys conducted on them. Bendock (1979, 1980) presented survey information on mountain lakes in the Colville drainage and in the vicinity of the "haul road" corridor. Mountain lakes in the Brooks Range are oligotrophic, usually glacial in origin, wi th relatively steep sides and rubble or boulder bottoms. Most mountain lakes have small, narrow basins. Chandler Lake, the largest, is 5 mi long and has a maximum depth of 62 ft. Large mountain lakes are ice covered from October through June. Typical fish associations include lake trout, burbot, grayling, round whitefish and slimy sculpin. Least cisco inhabit mountain lakes in the Colville and Sagavanirktok River drainages and Arctic char are widely scattered in lakes throughout the Brooks Range. Mountain lakes on which fisheries surv~ys have not been conducted are predominantly small, unnamed and LnacceesIbl.e ; however, many of these waters contribute to the sport and subsistence fisheries of the region and are increasingly being used as temporary water sources for exploratory oil drilling operations. Mountain lakes surveyed during 1981 are shown in Figure 2. Tulugak Lake Tulugak Lake, late 68 0 17'N, long. 151 0 28'W., lies 12 mi northeast of Anaktuvuk village, surface elevation is 1,940 ft. It is 0.8 mi long with a maximum depth of 40 ft. Water color is green and the Secchi reading was 9 ft on July 23, 1981. Bottom material varies from sand to large gravel and aquatic vegetation is sparse. Tundra vegetation extends to the waterline along most of its perimeter. Tulugak Lake is fed by ground water springs which flow a short distance and enter the lake along the east shore. A single outlet drains into the Anaktuvuk River from the north shore. The springs provide a constant source of year-round water to Tulugak Lake, thus providing continuous flow in the outlet throuBhout the winter. Hardness was 85.5 ppm; pH 9 and water temperature 52 F during the survey period A single 125' experimental gill net set overnight yielded a catch of 5 lake trout, 5 grayling, 7 round whitefish and 11 least cisco. While none were captured, burbot are reported to inhabit the lake~ Large numbers of fish spawning in the outlet of Tulugak Lake have been observed from the air during September. Limited subsistence fishing by residents of Anaktuvuk village takes place in Tulugak Lake, primarily in the fall. 7 n 151 0 ~ U h Lower Anayak Lake () Ironyivik -f- Lake ~ Natvakruak Lake Tulugak Lake o 5 I Anaktuvuk Pass 0 I 1520 Figure 2. Map of Anaktuvuk Pass showing locations of four mountain lakes surveyed during 1981. 8 Irgnyivik Lake Irgnyivik Lake, 1at. 68 0 26'N, long. 1510 16'W., lies 24 mi northeast of Anaktuvuk Pass. Surface elevation is 1,950 ft. It lies in a narrow basin and is 1.2 mi long with a maximum depth of 55 ft. There is a single inlet on the north end and an outlet on the south which flows into the Anaktuvuk River. The outlet may be discontinuous during midsummer and is marginal for fish passage. Aquatic vegetation is sparse and the lake bottom is comprised of sand, rubble and widely scattered large boulder reefs. Water color is green and the Secchi reading was 22 ft on July 23, 1981. Hardness was 103 ppm, pH 9 and water temperature was 58o F during the survey period. A single 125-ft experimental gi11net set overnight yielded a catch of 19 lake trout, 6 round whitefish and 1 grayling. Slimy scu1pins were observed in littoral areas. Access to the lake is limited to aircraft and snow machines and there was no evidence of recent sport or subsistence fishing activity. "Lower Anayak Lake" "Lower Anayak Lake," 1at. 68 0 32'N, long. 151 0 29'W is an unnamed lake that lies in the lower Anayaknaurak Creek drainage, 27 mi north of Anaktuvuk Pass. Surface elevation is 2,520 ft. The lake has a narrow basin, is 1.0 mi long with a maximum depth of 22 ft. Tundra vegetation extends to the waterline, leaving no exposed beaches. Bottom material is soft peat with scattered rubble reefs. There is one inlet and a single outlet, both of which appear to maintain adequate flow for fish passage, and have gravel or boulder substrates. The water is tea colored with a Secchi reading of 6 ft. On July 23, 1981, hardness was 171 ppm, pH 7.5 and water temperature 61oF. A single experimental gi11net set overnight yielded a catch of 9 lake trout, 4 round whitefish and 1 grayling. There was no evidence of recent sport or subsistence fishing activity. Natvakruak Lake Natvakruak Lake, 1at 68 0 22'N, long 151 0 43'W lies at the head of Natvakruak Creek, in the Chandler River drainage approximately 16 mi north of Anaktuvuk Pass. Surface elevation is 2,460 ft. The lake has a rectangular basin, is 1.2 mi long, and is 60 ft deep. There are short, exposed beaches comprised of large boulders and rubble. The water is tea-colored and had a Secchi reading of 20 ft on July 23, 1981. Aquatic vegetation is sparse. There are a single inlet and outlet, both of which may seasonally provide passage for fish. Hardness was 68 ppm, pH 8.5 and water temperature 55oF. One experimental gill net set overnight yielded a catch of five lake trout and one round whitefish. Slimy sculpin were observed in littoral areas. Considerable litter exists at several sites around the lake. There is also evidence of sport and subsistence fishing as well as past oil company activities at Natvakruak Lake. 9 Coastal Plain Lakes The Arctic coastal plain on the north Slope extends from cape Lisburne to the Canadian Border. At its greatest depth south of Barrow, the coastal plain extends 115 mi inland, while on the eastern border it is less than 10 mi deep. The coastal plain is characterized by abundant lakes, wet tundra, meandering streams, low relief and thermokarst features. Precipitation is low (5" to 7"annua11y) and surface drainage is poor due to flatness of terrain, continuous permafrost and low rates of evaporation. Lakes within the region are "thaw lakes" and cover up to 50 percent of the total plain area. Four lakes within the region are greater than 10 sq mi in area. The largest, Teshekpuk Lake, is 25 mi long and covers 315 sq mi. Lakes within the region generally tend to be shallow; however, a significant number have deep basins and provide year-round habitat for fish. Deep basins, where they exist, are considerably smaller than the total surface area of the lake, thus surface area alone does not adequately indicate which lakes support populations of fish. The amount of basin area may also limit species diversity and population size within a lake. Shallow lakes usually do not support fish except where seasonal access is provided by inlet and outlet streams. Species diversity and abundance varies throughout the coastal plain. Netsch et. a1. (1977) surveyed several coastal lakes and streams north of the Colville River, in the northern half of the National Petroleum Reserve - Alaska. This and other studies indicate that species diversity is lowest on both the eastern and western margins of the coastal plain and greatest in the central region lying south of Teshekpuk Lake and west of the Colville River. During the report period, 16 lakes within this area were surveyed (Fig. 3). These waters were moderately deep, ranging from 8 ft to 50 ft, soft and slightly basic. Many of the lakes had extensive, unvegetated shoal areas on which ice remains grounded throughout the winter. Submerged aquatic vegetation is sparse and sand is the most common substrate in both lake basins and river beds within this area. Both sport and subsistence fishing pressures are minimal. Much of this region will be leased for oil and gas exploration in the near future. Three additional lakes near Prudhoe Bay were also surveyed during the report period. None of the lakes surveyed are named on USGS 1:250,000 maps. A single 125-ft experimental gill net was set overnight in each of the coastal plain lakes. Table 2 lists the locations, physical characteristics and species captured in each of the waters surveyed. Life History Discussions of Coastal Plain Species Of the 16 coastal plain lakes surveyed west of the Colville River, 13 (81%) contained populations of fish. The most common species occurring within the area in terms of frequency of occurrence and catch per unit effort included least cisco, broad whitefish and lake trout, followed by round whitefish, humpback whitefish, burbot and grayling. Burbot are not readily captured by gill net, and thus may be more abundant than indicated. Ninespine stickleback and slimy scu1pins, while not captured, were found as food items in lake trout and burbot. The following discussions are based on fish captured in 1981, but also include samples from 1979 taken in Teshekpuk Lake. 10 -f- C 59 DO C 5 9 (J C57 I-' I-' GC41 C\] C 40 oC65 Q o C50 C 63 so C 52 CV C62 Cl C 43 o C 61 CJ C46 Q) .-';> 10 o I o Figure 3. Coastal Plain Province of North Slope showing locations of lakes surveyed during 1981. Table 2. Locations, physical characteristics and species captured in 19 coastal plain lakes during 1981. Surface Approx. Max. Secchi Long. Elevation Length Depth Reading Hardness pH Species Ref. 1/ oW. (ft. ) (mf.) (ft) (ft) (ppm) Captured C-32 70° 34' 154° 18' 8 3.2 20 7 103 9 50 LCI, BWF C-40 70° 09' 153° 55' 164 3.0 18 16 68 9 55 LT, BWF, LCI, RWF C-41 70° 12' 153° 39' 160 2.1 22 20 86 9 53 LT, LCI C-43 69° 46' 155° 18' 180 1.1 23 12 120 9 55 None C-44 69° 42' 155° 08' 250 1.9 22 15 103 9 56 None C-45 69° 39' 154° 58' 290 1.6 8 8 137 9 54 GR C-46 69° 46' 153° 28' 280 2.0 10 8 68 9 57 None C-50 70° 03' 153° 30' 145 3.6 45 20 86 9 54 LT, BWF C-52 69° 57' 153° 15' 200 3.0 50 15 86 9 57 LT, BWF, LCI, RWF, BB ..... NSB, SSC N C-57 70° 17' 153° 00' 120 2.5 37 22 103 9 51 LT, LCI, NSB C-58 70° 18' 152° 56' 122 2.2 10 8 86 9 55 LT, BWF, NSB C-59 70° 18' 153° 04' 123 2.3 44 20 103 9 55 LT, BWF, RWF, LCI, NSB C-61 69° 51' 152° 27' 210 1.5 30 20 86 9 55 LCI C-62 69° 53' 152° 11' 210 1.5 27 12 68 8.5 56 LCI, NSB C-63 70° 06' 152° 37' 86 2.0 8 6 86 9 62 B\vF, LCI, HWF, NSB C-65 70° 10' 152° 23' 141 2.2 15 15 86 9 55 LCI, NSB C-104* 70° 28' 149° 25' 28 0.6 5 205 7.5 32 None C-105* 70° 28' 149° 27' 20 0.2 2.5 171 7.5 32 None C-106* 70° 29' 149° 33' 7 0.8 7 7 103 8.0 32 None * Surveys were conducted on October 22, 1981, all other waters were surveyed during the third week of July, 1981. Least Cisco Least cisco are distributed throughout the North Slope of Alaska, primarily inhabiting mountain and coastal lakes and the lower reaches of large rivers. Anadromous least cisco from the Colville River enter the Beaufort Sea and forage as far east as Barter Island during the summer months. Least cisco were captured in 10 (63%) of the coastal plain lakes and were the most frequent and abundant species encountered. A total of 103 least cisco was captured in the coastal plain lakes and 26 were captured in Teshekpuk Lake. Of this total, 107 were sampled. The largest catches were taken from lakes C-62 (n=32) and C-32 (n=20). Least cisco ranged from 127 mm to 436 mm in length and averaged 288 mm , The length frequency of 107 least cisco is shown in Figure 4. Weights ranged from 20 g to 1,100 g and averaged 274 g. The female to male sex ratio was 1:1.3. Ages ranged from III through XXI. The age at maturity was IV for a smaller least cisco morph found in Teshekpuk Lake and Age IX for ciscos taken in the remaining waters. Least cisco are opportunistic feeders, utilizing a variety of prey found throughout the water column. Eighty percent of the least cisco stomachs examined contained food. The following food items were found in descending frequency of occurrence: aerial insects (primarily mosquitoes), snails, amphipods, clams, caddis larvae, ninespine stickleback, zooplankton and isopods. The first three categories represented 85% of the total food items. Growth rates of coastal plain and anadromous least cisco from the North Slope are compared to cisco from Minto Flats (Interior Alaska) in Figure 5. Least cisco from the Arctic Slope coastal plain exhibit slower growth, greater age at maturity and greater longevity than those from Interior Alaska. On the North Slope, lake resident cisco attain a greater ultimate size and longevity than their anadromous counterparts. In coastal plain lakes, least cisco are an important forage fish for both lake trout and burbot. Broad Whitefish Broad whitefish are distributed in lakes and streams throughout the North Slope and are reported to be anadromous in the Colville and Sagavanirktok Rivers. Broad whitefish were captured in seven (44%) of the coastal plain lakes surveyed. Seventy-nine broad whitefish were captured from coastal plain lakes, including Teshekpuk Lake, and 66 of these were sampled. The largest catches occurred in Teshekpuk Lake and Lake C-63. Broad whitefish ranged from 260 mm to 583 mm in length and averaged 463 mm. The length frequency of 66 broad whitefish is shown in Figure 6. Weights ranged from 190 g to 2,600 gand averaged 1,388 g. The female to male sex ratio was 1:1 and ages ranged from V to XX. The first age of maturity was X for both sexes of broad whitefish. 13 40- 3,Q- :r en ii: 0- 0- I I I • I 50 100 150 200 250 300 350 400 4lS0 500 LENGTH (mm) Figure 4. Length frequency of 107 least Cisco captured in Arctic coastal plain lakes. 14 400 350 300 ;' ./ ;' C 62 LAKE 250 PRUDHOE BAY (BENOOeK 1977) / " UPPER CHATANIKA RIVER (ALT 1971) / " 200 / VI / / / 150 / / / / / 100 / / / b 50 / II 11\ IV V VI VII VIII IX x XI Xli XUI XIV XV XVI XVII XVIII Figure 5. Back-calculated fork lengths of least cisco taken in C-62 Lake (coastal plain lake), Prudhoe Bay and Chatanika River (interior Alaska). 22 2 ::r I en i&: 12 oLL. a: 10 w m 8 :=: z::l 6 4 r 2 r I I I 'r I 200 250 300 350 400 450 500 550 600 650 LENGTH (mm) Figure 6. Length frequency of 66 broad whitefish captured in Arctic coastal plain lakes. 16 Forty-six percent of the broad whitefish stomachs examined contained food. Prey items in descending order of frequency included: clams, snails, chronomid larvae and zooplankton. Broad whitefish from the coastal plain lakes attain a smaller maximum size than those reported for the Mackenzie River (Hatfield, et al., 1972) and Siberia (Berg, 1949), however, maximum lengths are similar to those reported for Prudhoe Bay (Bendock, 1977) and Interior Alaska (Alt, 1972). Longevity is greater for coastal plain broad whitefish than for both the anadromous counterparts (Prudhoe Bay) and interior Alaska fish. Figure 7 shows comparative growth rates for three populations of broad whitefish. Lake Trout Lake trout are widely distributed across the North Slope, primarily inhabiting lakes, but also occurring in streams within the Colville, Sagavanirktok and Canning River drainages. Waters within the foothills region and the western margin of the coastal plain have few lake t rout; however, this species is well represented in the central coastal plain which marks the northern most distribution of this species in Alaska. Twenty-six lake trout were sampled from eight (47%) of the coastal plain lakes surveyed, including Teshekpuk Lake. The largest catches were from Teshekpuk Lake and Lake C-52. Lake trout ranged from 370 mm to 890 mm in fork length and averaged 631 mm. Weights ranged from 580 g to 9,700 g and averaged 3,545 g. The length frequency of 26 lake trout from coastal plain lakes is shown in Figure 8. The female to male sex ratio was 1:1.3. Ages ranged from VII to XXXV. The age of maturity for lake trout was XI and spawning by most individuals, based on gonad examination, appears to be nonconsecutive. Thirty-eight percent of the lake trout had empty stomachs. Of those that contained food, the following prey items were taken in descending order of frequency: ninespine stickleback; other fish including least cisco, slimy sculpin and lake trout; snails and clams. Age and growth, maturity and longevity of lake trout from coastal plain lakes compare closely with lake trout inhabiting North Slope mountain lakes, despite major differences between the two habitats. Other Species Round whitefish are distributed throughout the North Slope in both lakes and streams. While common in streams throughout the region, they are less frequently encountered in coastal plain lakes than in foothill and mountain waters. Round whitefish were captured in four (24%) of the coastal plain lakes that were surveyed. Fork lengths ranged from 163 mm to 387 mm (n=5), weights ranged from 40 g to 600 g and ages ranged from III to XIII. Humpback whitefish on the North Slope are primarily limited in distribution to the Colville River and other major streams across the coastal plain. One humpback whitefish was captured both in Teshekpuk Lake and in Lake C-63. Both of these lakes have large outlet streams which may be important 17 650 .. .. ' 600 550 500 450 400 COASTAL PLAIN LAKES 3'50 PRUDHOE BAY (BENOOCK 1977) MINTO FLATS (ALT 1972.) 300 ..... 250 00 200 150 100 50 II III IV V VI VII VIII IX X XI XII XIII XIV XV XVI XVII XVIII Figure 7. Back-calculated fork lengths of broad whitefish taken in coastal plain lakes, Prudhoe Bay and Minto Flats (interior Alaska). 6 5 :r CI) i:i: 4 u. o a:: LLl 3 to :IE :::> Z 2 100 200 300 400 500 600 700 800 900 LENGTH (rn m) Figure 8. Length frequency of 26 lake trout captured in Arctic coastal plain lakes. 19 migration corridors for humpback whitefish. This species seldom inhabits foothill and mountain lakes on the North Slope. Grayling are widespread in both lakes and streams across the North Slope. They are the principal species inhabiting foothill lakes and streams. While abundant in Teshekpuk Lake, only a single specimen was captured in another coastal plain lake (C-45). Burbot also have a widespread distribution, inhabiting both lakes and streams across the North Slope. Gill nets, the primary capture method, do not readily capture and hold burbot, thus catches in the coastal plain may not adequately define the distribution within this area. Burbot are reported to be present in Teshekpuk Lake and were captured in Lake C-52. Ninespine stickleback and slimy sculpin inhabit all maj or waters on the North Slope. While not captured in gill nets, these species were frequently observed and were found as prey items in larger fish inhabiting the coastal plain waters. Other species reported to occur in coastal plain lakes (Netsch et aI , 1977), but not encountered during our surveys include: Northern pike, Arctic cisco, Alaska blackfish, and fourhorn sculpin. Winter Char Habitats In The Anaktuvuk River Background: The Anaktuvuk River, second largest tributary to the Colville River, heads in the Endicott Mountains and flows north-northwest for 132 mi. It enters the Colville River 91 mi inland from Harrison Bay. The Anaktuvuk River drainage covers an area of 2,839 sq mi and the river's estimated mean annual flow rate is 1,420 cfs. The Nanushuk River, largest of three main tributaries entering the Anaktuvuk River, flows north for 94 mi and drains an area of 896 sq mi. There are numerous lakes in the Anaktuvuk River drainage. Shainin Lake, the largest, is 2.7 mi long and has a maximum depth of 56 ft. Deep lakes within the drainage are typically inhabited by lake trout, grayling and round whitefish. The Anaktuvuk River is heavily braided throughout most of its length and has bottom material ranging from fine sand in the upper and foothills region to large gravel and boulders in the middle and lower reaches. Spring areas, perennial sources of ground water, are abundant adjacent to and within the river valley, creating large fields of aufeis that remain throughout most of the open water season. Spring areas also maintain open leads in the river throughout the winter months. The largest springs occur in the main stem of the Anaktuvuk River, May Creek, as well as in the Nanushuk and the lower Kanayut Rivers. Anaktuvuk Pass, a small Nunamiut village, is located at the head of the Anaktuvuk River. There are two gravel air strips constructed for exploratory oil drilling adjacent to the Anaktuvuk River. Fishing pressure within the drainage is light. 20 Arctic char, lake trout, grayling, round whitefish, broad whitefish, burbot, slimy sculpin, and ninespine stickleback inhabit the Anaktuvuk River. Pink salmon, chum salmon and humpback whitefish have been captured at the mouth of the Anaktuvuk River. Bendock (1979) presented survey information obtained in the lower reaches of the river. Arctic char were first reported in the Anaktuvuk River by Roguski and Winslow (1970). Kog1 (1971) reported capturing anadromous char in the Colville River and rearing char in the upper Anaktuvuk River. Bendock (1980) reported on two fall concentrations of Arctic char in the Anaktuvuk River and estimated (by aerial survey) the largest group to contain over 15,000 fish, comprised of both spawning and non-spawning individuals. Following these earlier observations, the Sport Fish Division initiated an investigation to examine the distribution, migration timing and patterns, and overwintering habitats of Arctic char in the Anaktuvuk River. Bendock (1981) presented information on the age and growth, distribution, spawning and migration timing of Anaktuvuk River char. This report presents findings on the winter habitats of char based on a telemetry study of 12 radio-tagged char. Tagging Site Characteristics: The radio tagging site (Fig. 9) adjacent to Rooftop Ridge contains the largest fall concentration of both spawning and non-spawning anadromous char. The site is heavily braided, with several channels of flowing water traversing the flood plain during the summer months. Gravel bars within the flood plain are sparsely vegetated due to thick winter ice cover and scouring at breakup. River bed material is medium sized (2 to 5 in) smooth gravel interposed with small areas of finer material. During breakup the flood plain is bank-full with water. Peak discharge decreases rapidly in June; however, the river usually remains turbid throughout most of the summer. By late August the water becomes low and clear as discharge is further reduced by freezing near the headwaters. The Anaktuvuk River begins running ice by late September and freeze up commences shortly thereafter. Located within the riverbed and in adjacent arms of the river are ground water springs that discharge either directly into the Anaktuvuk or provide the only source of water for short side channels. Ground waters enter the system at 36o F to 39aF, thus areas in the vicinity of larger ground water sources remain ice-free for a limited distance throughout the winter. The remainder of the Anaktuvuk River that is not influenced by ground water freezes to the bottom and thus does not provide suitable habitat for fall spawning or overwintering fish. The sp rLng water cools rapidly as it travels from the source and at variable distances downstream is blocked by existing river ice. Water then flows through or around the blockage and freezes on the surface of the river bed or existing ice. In this manner, ice accretion occurs downstream from perennial water sources throughout the winter when air temperatures are below freezing, creating large aufeis fields. By late winter, aufeis up to 10 ft thick covers approximately 20 sq mi of riverbed immediately downstream from the Rooftop Ridge tagging site. The aufeis field below Rooftop Ridge remained through the summer of 1981 to form the nucleus of 21 zh--I I ARCTIC CHAR TAGGING SITE 10· 20 I I Figure 9. Anaktuvuk River showing the location of capture and release of twelve radio-tagged Arctic Char, 1980-1981. 22 the present season's field. The effects of aufeis on permafrost and river morphology in northern Alaska are discussed by Harden et a1. (1976). Smaller spring areas and aufeis fields occur intermittently throughout the Anaktuvuk drainage. Anadromous char first arrive at the Rooftop Ridge spring area in mid August. Adult non-spawners concentrate in dense schools in the main stem of the Anaktuvuk River while spawners occupy the spring-fed side channels adjacent to the main drainage. Spawning takes place in spring channels from early September through October. Following spawning, spent fish move to the main river and enter schools of non-spawners. The entire concentration of char is distributed within a 4-mi stretch of the Anaktuvuk River by late September. Following freeze-up, little is known about char habitats or movements until fall concentrations again appear the following year. Winter Movements: Due to the inaccessibility of the Anaktuvuk River, radio-telemetry was used as a method for monitoring the winter movements of char and to locate overwintering habitats under the ice. The techniques section of this report describes the equipment and procedure for implanting the radio transmitters. Twelve char were radio-tagged, of which six were spawners and six were non-spawners. Of the spawners, three were male and three were female. The sex of non-spawners could not be determined by examining external sex characteristics. The tagged fish ranged from 560 rom to 820 mm in fork length and averaged 662 rom. Weights ranged from 2,100 g to 5,000 g and averaged 2,750 g (6.1 lbs). All of the char were tagged and released in the Anaktuvuk River adjacent to Rooftop Ridge on Sept. 20-21, 1980 (Fig. 10) • Table 3 shows the length, weight, sex and radio frequency of the tagged char. An attempt was made to locate the radio-tagged fish at 2-week intervals using a fixed-wing aircraft. This procedure worked well until late March to early April, at which time the overwintering locations were sampled under the ice. Following the spring sampling period, the tags that remained functional were monitored at irregular intervals until the spring outmigration in June. Table 4 lists the dates when tracking was conducted and the number of tags functioning on each date. Radio tracking results indicate that char are "confined" residents of the limited overwintering habitat and that movement throughout the ice-covered months (October through May) is minimal. All of the char that were tagged in the spawning channel departed that location and occupied adjacent stretches of the main river, even though the spawning channel remained slightly warmer, and ice-free near its source, throughout the winter. There was a net upstream movement of both spawners and non-spawners throughout the winter. Figure 11 shows the distribution of tagged char in April, 7 months after their release. Movement was slight and variable during the winter tracking periods, resulting in minor shifts in position of tagged fish. The average distance traveled between the tagging location (September) and locations identified in April was 0.9 mi and ranged from a few feet to 1.6 mi (Table 5). . 23 I Z ha River . ... ' ". .":...... ·.. ., Togging Sites ~ I o 1/4 I I , Figure 10. Location of tagging sites in Anaktuvuk River, September, 1980. I Z h- River · ...... '.. " · '...... : . ... · . .. . • Togged in spawning channel o Togged in main river o 1/4 Figure 11. April distribution of tagged Arctic Char, seven months after release. 24 Table 3. Fork length, weight, sex and spawning conditions of twelve char radio-tagged in the Anaktuvuk River, 1980. (MHz) Fork Length Weight Spawning No. Date Frequency (mm) (g) sex Condition 1 9/21 151.000 575 2,100 Non-spawner 2 9/21 151.020 660 2,500 Non-spawner 3 9/20 151.040 586 2,200 Non-spawner 4 9/20 151. 060 600 2,500 Non-spawner 5 9/20 151.080 740 3,800 Non-spawner 6 9/20 151.100 630 2,100 Fern Spent 7 9/20 151.120 645 2,100 Fern Spent 8 9/20 151.140 560 2,100 Non-spawner 9 9/21 151.160 820 5,000 Male Spent 10 9/21 151.180 740 3,500 Male Spent 11 9/21 151. 200 710 3,000 Male Spent 12 9/21 151.220 678 2,100 Fern Spent 25 Table 4. Number of tags functioning on each radio tracking date. Date II Tags Operating Life (Mos.) 9-22-80 12 0 10-14-80 12 1 11-04-80 12 2 11-19-80 12 2 12-09-80 12 3 01-29-81 12 4 03-05-81 11 6 04-02-81 10 7 04-22-81 10 7 05-12-81 4 8 06-08-81 2 9 06-17-81 2 9 26 Table 5. Distance travelled by radio tagged Arctic char in the Anaktuvuk River between 9/21/80 and 4/1/81. Fish II Tag Site Sex Distance Traveled (mi) 1 Spawning Channel 1.6 2 Spawning Channel 0.8 3 Main River 0.8 4 Main River 0.9 8 Main River 0.07 7 Main River female 1.0 9 Spawning Channel male 0.7 10 Spawning Channel male 1.1 11 Spawning Channel male 1.3 12 Spawning Channel female 0.7 27 It was assumed that char depart the overwinter location and begin a seaward migration at breakup. Continued monitoring of tagged fish, however, indicated that the char remained concentrated at the overwintering site through mid-June, which in 1981 was approximately one month after breakup occurred in the middle and upper Anaktuvuk River. On June 8, the Anaktuvuk River cleared up temporarily and an aerial survey confirmed the presence of large numbers of char still concentrated at the overwinter site. No fish, however, were observed above, or below the site. By this date, breakup had occurred throughout the length of the Anaktuvuk and Colville Rivers. Later monitoring of char concentrations by aerial survey was hampered by turbid water conditions. On June 17th, the only remaining char with a functioning transmitter (#3) was located at the mouth of the Anaktuvuk River, approximately 55 mi below the overwintering site. The following day, a thorough search of the lower Anaktuvuk and Colville Rivers failed to locate the char and it was assumed that the fish had completed the seaward migration through the remaining 90 mi of the Colville River. Gill netting in the lower Anaktuvuk River during the spring of 1980 showed large numbers of char out-migrating on June 10, which is 1 week earlier than the radio-tagged individual departed in 1981. It appears, however, that the departure from overwintering habitats more closely coincides with breakup along the Beaufort Sea coast than with breakup near the wintering locations more than 100 mi to the south. It further appeared that any foraging or wandering away from the overwintering site prior to the out-migration was minimal. Arctic char radio-tagged in the Anaktuvuk River were confined to a small stretch of river and essentially sedent.ary for a period of time exceeding 8 months. Overwintering Habitat and Sampling The overwintering site and sampling locations at Rooftop Ridge is shown in Figure 12. Descriptions of the habitat and under-ice sampling were conducted in late March through early April 1981. The entire overwintering site was less than 3 mi in length, consisting primarily of two short channels of .water flowing under the ice. Water originated in spring areas that were. ice-free at the source. As the water traveled away from the source, it cooled rapidly and was soon flowing under a layer of surface ice. The largest open water area was approximately 1/2 mi long. pownstream from the open water, an air space separated the flowing water from the surface ice and the ice had a rough, irregular bottom. Further downstream the ice increased rapidly in thickness and within 2 mi of the spring area, water was blocked by aufeis and was incorporated in the field. Fish inhabited all locations with flowing water. Table 6 lists the physical and chemical characteristics of each sample location. Figure 13 shows a diagramatic cross-sectional view of the habitat. Monofiliment gill nets were set for 4 hours at sites 2 and 3. A gill net was used as a seine to sample fish from site 1. Table 7 lists the species and numbers of fish captured at each site. All of the char captured at site 1 (open water) were subadults ranging from 4 to 5 years of age. Char ranging from 5 through 9 years of age were captured at sites 2 and 3. The combined female to male sex ratio of 24 captured char was 1:0.4. All of the char had empty stomachs. 28 I Z be- .... ~ .'... Open Water Areas Water Flowing Under Ice Grounded Ice and Aufies 1/4 I • Sampling Locations Figure 12. Anaktuvuk River overwintering site and sampling locations, April, 1981. 29 Table 6. Physical and chemical characteristics of three sampling sites in the Anaktuvuk River April, 1981. Sample Location 1 2 3 Snow Depth (in) 0 12 15 Ice Depth (in) 0 16 77 Air Space (in) 0 15 0 Water Depth (in) 24 10 39 Water Temp. (oF) 34 33 0 DO (ppm) 11 8 11 pH 8 8 8 Hardness (ppm) 137 171 137. Velocity (fp s) 1.0 1.5 0.7 Species Present AC, GR, RWF, SSC AC AC, LT, RWF, SSC 30 0 SNOW approximate vertical scale: ~ in. 1 ft. C) ICE 0 AIR © WATER ® STREAM BED sample site sample site 2 sample site 3 w ...... -- 0 0 -0 <:) 0 0 0° 0 O000 0 ~ ~ ~~ Figure 13. Schematic drawing of snow, ice and water depths at three Anaktuvuk River sampling sites April, 1981. Table 7. Species, and numbers of fish captured at three over wintering sites in the Anaktuvuk River, 1981. Species Captured Sample Location AC LT GR RWF sse Total 1 19 o 34 7 3 63 2 6 o o o o 6 3 8 1 o 1 2 12 Total 33 1 34 8 5 81 32 Densities of char in the overwintering location appeared higher than the limited sampling indicates. At net site 2, an observer could look across the under-ice air space and see the backs of fish protruding above the water surface, as well as hear fish swim away from a disturbance. The water at this location was a maximum of 10 in deep. The schools of fish reacted strongly to disturbances on the ice and along the shore of open water. It was apparent that, while open water areas are available to the larger char, the preferred habitat was in ice-covered water. Additional Sampling of Spring Areas Four additional spring areas in the Anaktuvuk River drainage were sampled for water chemistry and fish presence during April 1981 All of the sites had open water, terminating in aufeis fields. Both sites on the Nanushuk River have fall concentrations of char, while the sites adj acent to the Kanayut River do not have char. Table 8 lists the site characteristics and fish captured at these locations on April 2, 1981. The site characteristics were measured at the spring sources in open water and samp~ing for fish was conducted only in the ice-free areas. Thus, if these sites are similar to those sites sampled at Rooftop Ridge, large numbers of overwintering fish may have occupied the under-ice habitats between the open leads and the aufeis fields. Juvenile grayling were the only species captured at these additional sites. Segregation of Fish Little is known about the organization of fish by species and size in limited overwintering habitats. Bendock (1980) sampled several species, comprised of all age groups, inhabiting overwintering pools in the Colville River where segregation by size or species was not apparent. There is some evidence that fish overwintering in the Anaktuvuk River segregate either by size or species. Site 1 at Rooftop Ridge had only adult grayling while the Nanushuk had only juvenile grayling. Site 1 also had only subadult char, while sites 2 and 3 had larger char. Adult round whitefish were captured in Site 1, but no juveniles were present. Further sampling is necessary to determine the significance of this feature. Radio Telemetry of Char in the Sagavanirktok River Drainage To confirm the winter movement and habitat findings from Anaktuvuk River char and to describe additional overwintering habitats of Arctic char, 16 char were equipped with radio tags in the Sagavanirktok River drainage during September 1981. Four fish were tagged in each of the following streams: Echooka, Ivishak, Saviukviayak and Lupine Rivers (Fig. 14). Char spawning occurs in each of these streams; however, it is not known if overwintering takes place at a single location or at several sites within the drainage. Fourteen of the radio-tagged char were in spawning condition while two were adult, nonconsecutive spawners in bright condition. Of the spawners, six were female and eight were male. The sex of the bright char could not be determined by examining external characteristics. The radio-tagged char ranged from 520 rom to 730 rom and averaged 616 mm, Weights ranged from 33 Table 8. Site characteristics and species present in four spring areas in the Anaktuvuk River drainage April, 1981. Snow Ice Water D. Hardness Velocity Location (in. ) (in. ) (in. ) (ppm) pH (ppm) fps Species Nanushuk R. 36 0 0 10 8 8 171 1.0 GR May Creek 36 0 0 8 7 8 205 1.0 0 Anak. above Kanayut 34 0 0 10 9 7.5 205 4.0 0 Anak. below Kayayut 34 0 0 12 9 8 154 1.5 0 w ~ C:=====:I==~===2:ipmlJes Figure 14. Locations of Radio-Tagged Arctic Char in the Sagavanivktok River Drainage, September, 1981. 35 1,500 g to 4,100 g and averaged 2,244 g. Physical characteristics of the tagged char, radio frequencies and capture site characteristics are listed in Table 9. All ~ish were tagged and released during the second week of September, 1981. Results of this study will be reported at a later date. Arctic Char Aerial Counts Aerial counts of Arctic char have been attempted annually in the Sagavanirktok River drainage since 1971. All of the major tributaries to the Sagavanirktok River determined to be char spawning areas were counted between 1971 and 1975. Since 1976, only the Ivishak and Echooka Rivers have been counted. The Ivishak River contains the largest aggregation of char in the system and is considered an index to overall population levels. Prior to 1977, counts were conducted by helicopter; however, subsequent counts have been made using fixed wing (Piper PA-18) aircraft. All of the estimates have been made during mid-September. Aerial counts are not considered to be estimates of the char populations, but rather are a inexpensive means of annually Lndex tng : both the distribution and general abundance of char. Securing safe flying weather has been a continual problem when conducting the char counts, and poor weather has resulted in the loss of several years;' counts. Arctic char in two locations in the Anaktuvuk River drainage have been counted since 1979; however, only the "Tu1uga" group will be counted as an index area in future years. Table 10 lists·· the values for previous estimates in the Sagavanirktok and Anaktuvuk drainages. ' : Counts in 1981 were conducted on September 14, which is 1 week earlier than in previous years. The low numbers of spawners in the Echooka River in 1981 is a result of the count period preceding the peak of spawning activity. An overflight of the Echooka River in October 1981 showed large numbers of spawning char in traditional areas. Counts from other areas in 1981 compared favorably with previous estimates. Experimental Fish Stocking - Pt. Barrow Isatkoak Lagoon located at Pt. Barrow, Alaska is a series of three interconnected waters that formerly were a salt water lagoon (Fig. 15). Following the construction of three impoundment structures and dredging, the upper two impoundments are now fresh and potable. The lower lagoon (Tasigarook Lagoon) is the municipal sewage lagoon and contains the outfall from Barrow's water treatment facility. A concrete dike has been constructed between the lower lagoon and the middle lagoon, and a gravel dike with 11 arched culverts separates the middle from the upper lagoon. In past years, the middle lagoon has served as the municipal water source for Barrow. Dredging has occurred in the middle and upper lagoon and has created maximum depths of 12 ft and 25 ft respectively. The upper lagoon is the proposed future water source for Barrow due to its greater depth, and limited dredging is expected to continue in the future. 36 Table 9. Physical characteristics of tagging sites and Arctic char radio tagged in the Sagavanirktok River drainage, 1981. Freq. F.L. Wt. 151. ppm Location II Sex Mat* (rom) (g) (MHZ) pH Hardness Lupine R. 1 M Sp 585 1800 520.5 40°F 8.5 188 2 F Sp 600 1500 561.5 3 F Sp 610 2000 460.8 4 M Sp 580 2000 480.6 Saviukviayak 1 F Sp 635 2200 610.9 39°F 8.5 154 River 2 M Sp 535 1500 682.9+ 3 F Sp 650 2700 651. 7 4 M Sp :570 1800 710.6 0 Ivishak (Hi) 1 M Sp '670 2800 830.5 39 r.~-, 8.5 137 2 M Sp 730 4100 870.9++ Ivishak (Low) 1 NS 535 1800 790.9+ 2 NS 520 1500 750.9+ Echooka River 1 F Sp 600 2100 890.8 40°F 8 154 2 M Sp 710 3000 910.8 3 M Sp 655 2500 950.4 4 F Sp 665 2600 990.7 NS Non Spawner * Spawner 37 Table 10. Aerial estimates of anadromous char in index areas of the Sagavanirktok and Anaktuvuk Rivers, 1971-1981. LOCATION Sagavanirktok R. Anaktuvuk R. Year Ivishak Echooka "Tuluga" Nanushuk 1971 12,470 1,137 1972 11,937 1,688 1973 8,992 1,883 1974 11 ,000 2,160 1975 8,306 852 1976 8,570 2,254 1979 24,403 814 15,717 934 1981 24,873 316 10,563 1,005 38 c C) (/) I o 500' 1000 Figure 15. Isatkoak Lagoon Complex at Point Barrow, Alaska. 39 Following a request from the city of Pt. Barrow, Isatkoak Lagoon system was evaluated for an experimental stocking program to enhance recreational fishing opportunities for local residents. In April 1980, late winter dissolved oxygen values were obtained from the middle and upper lagoons (Table 11). In July 1980, a more complete water analysis was made (Table 12) and both waters were sampled overnight using experimental gill nets. Local residents reported that native fish were not present in the lagoon and gillnetting confirmed that observation. However, a single ninespine stickleback carcass was found on the shore of the dike separating the middle and upper lagoons. Isatkoak Lagoon remains ice-covered throughout much of the year. Breakup is usually a slow process beginning in June, and patches of ice may still be present through July. Freeze-up usually occurs by October. The lagoon has a soft, muck bottom with isolated patches of gravel that have been exposed by dredging. Aquatic vegetation is sparse and exposed beaches are composed of peat and tundra. The middle lagoon has a nearly rectangular shoreline, while the upper lagoon has an irregular shoreline terminating in two forks that describe the small (less than 5 sq mi) drainage basin of the lake. In June 1981, 50,000 (newly hatched) grayling fry were stocked in the upper lagoon near the confluence of the two drainage forks. At the time of stocking, the lagoon was ice-covered, with only a small amount of open water in the arm of the lagoon south of the Barrow air strip. An evaluation of the stocking success will be conducted in the future. Dalton Highway The Dalton Highway, built in 1974 and transferred to the State in 1978, was re-opened to sport fishing by Board of Fisheries action in 1979. Access during 1979 was limited to permitted commercial users which limited sport fishing opportunities primarily to truckers and employees of Alyeska and the State Department of Transportation. During June, July and August of 1981 the highway was opened for travel by the general public from the Yukon River to Disaster Creek, approximately 150 mi north of the Yukon River. During the summer of 1981 sport fishing pressure was monitored to determine the effects of increased access to this section of road. The Sport Fish Division made 12 vehicle trips covering 35 days of this open period, observing fishermen and conducting creel census interviews enroute. Additional information on the location and intensity of fishing pressure was obtained from overflights in fixed-winged aircraft. Information gathered in summer 1981 suggests that opening the lower end of the haul road to public access has had no appreciable effect on sport fishing pressure and harvest. The area opened to the public excludes many of the best fishing waters along the road and it appears that sport fishing was an activity not planned for by many travellers. Some of the factors contributing to the low fishing and tourist activity during 1981 included: 1) cool and wet weather throughout most of July and August, 2) extremely rough road conditions culminating in a general walk-out by the commercial trucking industry, 3) poorly situated and infrequent camping facilities, 4) placer mining on several streams creating turbid water throughout the 40 Table 11. Late winter dissolved oxygen values obtained at Isatkoak Lagoon. Est. Snow Ice Water Dissolved Surface Depth Depth Depth Oxygen Lagoon Acreage (in) (in) (in) (ppm) Middle 120 10 78 60 7.2 Upper 170 6 84 120 7.0 Table 12. Water quality values obtained from Isatkoak Lagoon in July, 1980. Middle Lagoon Upper Lagoon Date 7-14-80 7-15-80 Max Depth 12' 25' Water Color Gray-Green Gray-Green Secchi Depth 3' 3' H Temp (oF) 20 39 45 Hardness (CaC0 222 mg/L 51 ppm 3) Alkalinity (M-O, CaC0 51 mg/L 51 ppm 3) CO 2 20 mg/L 15 ppm pH 7.5 9 41 summer, and 5) the long distance and travel time required from the nearest towns and villages. Some of the above f ac tors may improve with time; however, others such as rough and dusty road conditions are an expected part of the haul road experience. While angler interest appears to remain high, most fishing is conducted by area residents and employees, and the Department does not anticipate dramatically increased fishing pressure with eased public access until conditions improve substantially. Future efforts to monitor sport fishing are expected to continue at a similar level. LITERATURE CITED Alt, K. T. 1971. A Life History Study of Sheefish and Whitefish in Alaska. Alaska Dept. of Fish and Game. Federal Aid in Fish Restoration, Annual Report of Progress, 1970-1971. Project F-9-3, 15(R-I-A): 31p. 1972. A Life History Study of Sheefish and Whitefish in Alaska. Alaska Dept. of Fish and Game. Federal Aid in Fish Restoration, Annual Report of Progress, 1971-1972. Project F-9-4, 34p. Bendock, T. N. 1977. Beaufort Sea estuarine fishery study. In: Alaskan OCS Principal Investigators Annual Reports, U.S. Dept. of Commerce, NOAA ResEarch Unit 233. 1979. Inventory and cataloging of Arctic area waters. Alaska Dept. of Fish and Game. Federal Aid in Fish Restoration, Annual Report of Progress, 1978-1979, Project F-9-11, 20(G-I-I-): 64p. 1980. Inventory and cataloging of Arctic area waters. Alaska Dept. of Fish and Game. Federal Aid in Fish Restoration, Annual Report of Progress, 1979-1980, Project F-9-12, 21(G-I-I-): 1-31p. 1981. Inventory and Cataloging of Arctic area waters. Alaska Dept. of Fish and Game. Federal Aid in Fish Restoration, Annual Report of Progress, 1980-1981, Project F-9-13, 22(G-I-I): 1-33. Berg, L. S. 1949. Freshwater fishes of the USSR and adjacent countries (translation). Zool. Inst. Akad. Nauk. 27, 39, 30. Harden, D., P. Barnes, and E. Reimnitz, 1976. Distribution and character of Naleds in Northeastern Alaska. U.S. Geological Survey, Open File Report 77-91. Menlo Park, Calif. 20p. Hatfield, C. T., J. N. Stein, M. R. Falk, and C. S. Jessop. 1972. Fish resources of the Mackenzie River Valley. Fisheries Service, Environment Canada, Interim Report I, Vol. I., II, 247p. 42 Kogl, D. 1971. Monitoring and evaluation of Arctic area waters with emphasis on the North Slope drainages: Colville River Study. Alaska Dept. of Fish and Game. Federal Aid in Fish Restoration, Annual Report of Progress, 1970-1971, Project F-9-3, 12(G-III-A): 23-61. Netsch, N., E. Crateau, G. Love, and N. Swanton. 1977. Freshwater fisheries reconnaissance of the coastal plain of the National Petroleum reserve-Alaska (NPR-A), July and August 1977, preliminary report. U.S. Fish and Wildlife Service, Anchorage, Alaska. 214p. Roguski, E. and P. Winslow. 1970. Monitoring and evaluation of Arctic waters with emphasis on the North Slope drainages. Alaska Dept. of Fish and Game. Federal Aid in Fish Restoration, Annual Report of Progress, 1969-1970. Project F-9-2, 11(1S-C): 279-301. Prepared by: Approved by: Terrence N. Bendock Richard Logan, Ph.D. Fishery Biologist Dirctor, Sport Fish Division Mark C. Warner, PhD. Sport Fish Research Chief 43 Volume 23 Study No. G-I-P-A STATE OF ALASKA Jay S. Hammond~ Governor Annual Performance Report for INVENTORY AND CATALOGING OF SPORT FISH AND SPORT FISH WATERS OF WESTERN ALASKA Part A: Arctic Char Life History Study by Alfred DeCicco ALASKA DEPARTMENT OF FISH AND GAME Rvnald o. Skoog, Commissioner DIVISION OF SPORT FISH Richard Logan, Director Volume 23 Study No. G-I RESEARCH PROJECT SEGMENT State: ALASKA Name: Sport Fish Investigations of Alaska Project No.: F-9-14 Study No.: G-I Study Title: INVENTORY AND CATALOGING Job No.: G-I-P-A Job Title: Inventory and Cataloging of Sport Fish and Sport Fish Waters of Western Alaska Cooperator: Alfred DeCicco Part A: Arctic Char Life History Study Period Covered: July 1, 1981 to June 30, 1982 ABSTRACT This report presents background information and data from the first year of a 4-year life history study of Arctic char, Salvelinus alpinus (Linnaeus), in northwestern Alaska. Spawning grounds were located on the Anisak, Nimiuktuk, Kelly, Kugururok and Eli Rivers of the Noatak River system and spawning counts were made when possible. The Kelly, Kugururok and Nimiuktuk Rivers had the most spawning activity. Spawning grounds were also located and surveyed on the Wulik, Kivalina and Omikviorok Rivers. A total of 992 Arctic char spawners was tagged in Noatak River tributaries and 276 overwintering char were tagged in the Kivalina River. Fifteen Noatak River tags were recovered in 1981, indicating a post spawning movement out of tributary streams into the Noatak. Spawning char in the Noatak system ranged in fork length from 396 to 870 mm for males and from 425 to 724 mm for females, with a male to female sex ratio of 1:2.53. Modal gill raker counts were 22, 23 and 22 for samples from the Kivalina River, Kotzebue Sound and Trail Creek respectively. Pyloric caecae from 20 juvenile char taken in Trail Creek ranged from 23 to 33, with a mean of 28.2 and a mode of 27. Mean fecundity of Noatak River char was 5,696 ova/female. Overwintering char counts of 101,826 for the Wulik River and 45,355 for the Kivalina River were obtained by aerial survey. Scope Kotzebue Sound and Chukchi Sea drainages of northwestern Alaska contain populations of Arctic char which presently support light sport fishing and locally intensive subsistence fishing efforts. Biological investigations of char in the region have been limited to the Wulik River and to a lesser degree the Kivalina River. In anticipation of increased sport fishing pressure and proposed mineral development, the Sport Fish Division of the Alaska Department of Fish and Game is undertaking a 4-year study to inves tigate various life history aspects of Arctic char populations in these drainages. No biological information on movements, discreteness of popu lations, system interchange, spawning, or early life history of Arctic char exists for the Noatak River, Kobuk River or the many smaller coastal streams in the area. This study addresses this informational gap and will compliment existing information in previously studied areas. Age and growth, early life history, and physical/chemical survey data will be compiled as collected and reported when available on all streams for comparative purposes. KEY WORDS Arctic char, Western Alaska, Wulik-Kivalina, Noatak, Kobuk Rivers, aerial surveys, Floy tagging, spawning movements. BACKGROUND The Arctic char of northwestern Alaska is important to the local subsis tence economies of Kivalina, Noatak and Kotzebue and is becoming an in creasingly sought-after sport fish by local and non-local anglers. Mineral exploration in the upper Wulik and Kivalina Rivers and possible mineral development in other watersheds, with its associated population increases, could place additional demands on the char and their habitat. Previous work in the area has primarily been focused on the Wulik and Kivalina Rivers. Sarrio and Kessel (1966) presented information on subsistence utilization of fish by Kivalina residents. They present harvest levels of 97,600 pounds for the fall of 1959 and 124,000 pounds for the fall of 1960. Winslow (1969) documented the fall subsistence harvest on the Wulik River, showing an estimated harvest of 120,000 pounds of char. Winslow also presented the first biological data on Wulik River char. He sampled 139 fish and presented age and growth data. Gill raker counts were taken on three fish. Alt (1978) presented information on various life history aspects of Wulik and Kivalina River char. Maj or spawning and overwintering areas were delineated and information on migrations and spawning was given. There have been several surveys in the past, however, they were done by various biologists in different years and arrived at by different methods. As such, no conclusions can be drawn from these survey data, but they are valuable as relevant existing data. Aerial surveys conducted by the Division of Commercial Fisheries in 1968 enumerated 90,235 char 45 overwintering in the Wulik River and 27,460 in the Kivalina River. From these counts they estimated that 180,000 to 225,000 char were present in the Wulik River and 46,000 were present in the Kivalina River. A survey in 1969 by the Division of Commercial Fisheries showed 297,257 char present in the Wulik River. Alt (1981) presents estimated overwintering populations from subsequent aerial survey data as 137,545 for the Wulik River and 39,360 for the Kivalina River in 1979; and 124,908 for the Wulik River and 43,661 for the Kivalina River in 1980. In 1966, 1967, and 1968 the Division of Commercial Fisheries tagged 143 Arctic char near Shashalik Spit and along the Baldwin Peninsula in Kotzebue Sound incidental to their chum salmon research efforts. Of a total of 33 tag recoveries; 19 were from the tagging area, 7 were from the Noatak River, 4 were from the Wulik River, 2 were from the Kobuk River and 1 was from Port Clarence on the Seward Peninsula. These tagging data indicate a mixing of char stocks in Kotzebue Sound. There is increasing pressure on char stocks in the Noatak River. The river is known in the area as supporting a large char population. Residents of Noatak take char for subsistence use by seining in the fall and by "hooking" through the ice in winter. During the summer, the Noatak River is a popular wilderness float trip, and increased recreational activity due to the newly designated Park-Preserve status can be expected. National Park Service estimates of traffic in the area for 1981 were 1,000 floaters on the Noatak River and 800 floaters on the Kobuk River (Gil Hall, pers. comm , ) In August of 1980 Alt (1981) located char spawning areas by aerial survey on the Noatak River and 98 char in the Kelly River drainage were tagged. Arctic char have been taken in subsistence catches on the Kobuk River at Noorvik, Kiana, and Ambler. Kobuk residents have reported taking small numbers of char in the upper Kobuk incidental to fall seining for sheefish and whitefish. Reports indicated that the Squirrel River was the most important char stream in the Kobuk system. Common and Scientific names of fish found in the study area are given in Table 1. RECOMMENDATIONS Research 1. Research on the life history of Arctic char in northwest Alaska should continue. 2. Due to shortages of manpower and funding, the Kobuk River should be dropped from the study area. 46 Table 1. List of common names, scientific names and abbreviations of fish found in study area. Common Name Scientific Name & Author Abbreviation Alaska blackfish Dallia pectoralis Bean BF Arctic char Salvelinus alpinus (Linnaeus) AC Arctic grayling Thymallus arcticus (Pallas) GR Arctic Lamprey Lampetra japonica (Martens) AL Bering cisco Coregonus laurettae (Bean) BCl Broad whitefish Coregonus nasus (Pallas) BWF Burbot Lota Iota (Linnaeus) BB Chinook salmon Oncorhynchus tshawytscha (Walbaum) KS Coho salmon Oncorhynchus kisutch (Walbaum) SS Dolly Varden Salvelinus malma (Walbaum) DV Humpback whitefish Coregonus pidschian (Gmelin) HWF lnconnu (sheefish) Stenodus leucichthys (Guldenstadt)" SF Lake trout Salvelinus namaycush (Walbaum) LT Least cisco Coregonus sardinella Valenciennes LCl Longnose sucker Catostomus catostomus Forster LNS Ninespine stickleback Pungitius pungitius (Linnaeus) NSB Northern pike Esox lucius Linnaeus NP Pink salmon Oncorhynchus gorbuscha (Walbaum) PS Round whitefish Prosopium cylindraceum (Pallas) RWF Slimy sculpin Cottus cognatus Richardson SSC 47 Management 1. Monitoring of the sport and subsistence char harvest should continue. 2. Monitoring of mineral exploration efforts in the area should continue. OBJECTIVES 1. To begin a physical-biological survey of the Wulik-Kivalina and Noatak Rivers and selected Chukchi Sea drainages. 2. To determine movements, run timing, distribution, and system interchange of Arctic char in the waters of the study area. 3. To locate and describe Arctic char spawning areas within the study area. 4. To survey overwintering and spawning populations of Arctic char within the study area. 5. To collect angler and subsistence use information on important sport fish species within the job area with emphasis on the Wulik-Kivalina, Noatak, and Kobuk Rivers. All the Job Objectives are listed, however only certain aspects could be addressed in this first year. Many findings, like physical survey data and char system interchange, will be reported on when data are more complete. Study Area The study area includes the drainages of the Kobuk, Noatak, Wulik and Kivalina Rivers, as well as smaller coastal streams flowing into the Chukchi Sea between the communities of Kivalina· and Kotzebue. The total area included is 26,117 square miles. Kotzebue is the population and transportation center of the area, with outlying villages located on the major rivers in the area. Kivalina is located at the mouth of the Wulik River; Noatak on the Noatak River; Noorvik, Kiana, Ambler, Shungnak, and Kobuk on the Kobuk River. Arctic char occur in these rivers and many smaller streams. Research within the study area is confined to the major char-producing streams. This work area may change as more is learned of char distribution and abundance. During 1981 emphasis was placed on the Noatak River system. A map of the study area is presented in Figure 1. TECHNIQUES Float-equipped Cessna 185 and PA-18 aircraft and wheel-equipped PA-18 aircraft were used to transport field personnel and equipment to and from a base camp. Surveys to locate spawning grounds were conducted using the same aircraft. Spawning areas were located by flying along streams at low level and observing fish. Ground checks were made to confirm that species observed were Arctic char. Most major middle Noatak tributary streams were 48 ~_ ...... -- ",,_. - ----...... " "-, ...... - Kotzebue U' . 0(/ ~<:::> 1- 50 o I I I ., I 50 o I II I I Figure 1. StudyArea initially surveyed during August of 1980. Spawning areas were delineated on U.S. Geological Survey 1:250,000 topographic maps. Spawning ground aerial surveys were conducted from a wheel-equipped Piper PA-18 aircraft flying at low level. Numbers of fish were determined by counting individual fish and estimating larger concentrations by tens or hundreds. Some spawning areas were surveyed a second or third time if water, wind or sunlight conditions restricted visibility. Because of high water during the summer of 1981 all spawning areas were not surveyed with confidence. Counts of overwintering fish were flown on the Wulik and Kivalina Rivers in late September using a PA-18 aircraft. Large concentrations of fish were estimated to the nearest thousand. Char were captured for tagging using hook and line, a 80' x 10' 3/4" bar measure seine and a 90' x 6' 1!t;" bar measure seine. Transportation to tagging areas was by Cessna 185 and Piper PA-18 aircraft. A Zodiac Mark II inflatable boat equipped with a 35hp outboard jet was used on the Nimiuktuk, Kelly and Kivalina Rivers. The Kelly River and Wrench Creek were floated using 12' Avon Redshank rafts in early August. Char were captured on spawning grounds in the Noatak drainage and tagged using Floy internal anchor tags inserted under the skin between the last two dorsal fin rays so that the tags lodged between adjacent pterygiophores. Tags were color-coded to major spawning streams on the Noatak River, the Wulik River and the Kivalina River; tags were inscribed with "ADF&G Kotz", indicating Alaska Department of Fish and Game, Kotzebue. A $2.00 reward for char tags was paid by the Commercial Fisheries Division, which staffs a permanent office in Kotzebue. Char tags were recovered by Commercial fishermen in Kotzebue Sound, subsistence fishermen from Noatak village and ADF&G personnel. Additional recoveries will probably come from area sport fishermen. All char tagged were measured to the nearest millimeter from the upper snout to the fork of the tail, and weighed to the nearest 25 grams using a 6 kilogram Chatillion spring scale and a basket net. Spawning female char were captured for fecundity data using hook and line and a 90' x 6' 1!t;" seine dragged by hand through a spawning area. Ovaries were weighed to the nearest 0.1 gram using an Ohaus Dial-a-gram balance. Egg diameters were taken by measuring 10 eggs to the nearest millimeter in the field. Ovaries were then preserved in 10% formalin and stored in 36-oz. Whirl Pacs. Ovaries were boiled in the laboratory and separated for counting. The number of ova was determined gravimetrically by weighing a sample of about one-fourth the ovary and counting the eggs. Checks by counting the complete ovary showed an error of about 3% using this method. Saggital otoliths were taken for aging from char killed for fecundity data, from those killed incidental to tagging and from overwintering fish from the Kivalina River. Otoliths were stored dry in coin envelopes and aged in the laboratory by immersing them in loess solution (51 parts 95% alcohol, 7 parts glycerin, 42 parts distilled water) and examining them under a dissecting scope. Juvenile char were captured using a small mesh dipnet. Outmigrating char smolts were captured using a beach seine in the lower Noatak River by 50 Commercial Fisheries Division incidental to chum salmon fry capture efforts. Subsistence harvest data were collected by interviewing Noatak Village residents in conjunction with the collection of recovered tags. Sport fish harvest data were collected by personal interview. FINDINGS In the 1981 field season, 1,289 Arctic char (Salvelinus alpinus Linnaeus) were tagged in the study area; of these, 992 were tagged as spawners in Noatak River tributaries, 21 as spawners in the Wulik River, and 276 as overwintering fish in the Kivalina River. During preliminary work in 1980 an additional 98 spawners were tagged in the Kelly River, 28 in the Wulik River, 9 in the Kivalina River and 5 in the Omar River. The total number of char tagged, by sex, type, year and location, is presented in Table 2. Fifteen tags have been recovered in the study area. Of these, two recovered in the Kotzebue Sound commercial salmon fishery were tagged in the Kelly River as spawners in 1980, and 11 recovered in subsistence seining on the Noatak River were tagged as spawners in the Noatak tributaries in 1981. These recoveries support the hypothesis that, after spawning, most fish in the Noatak system move into the main Noatak River to overwinter. The two remaining recoveries were made at the mouth of the Noatak. Both of these fish were tagged as spawners in the Nimiuktuk River in 1981. These recoveries are discussed in the section on movements. Movements of Spawners Noatak River: There are both summer and fall movements of prespawning Arctic char into spawning areas on the Noatak River. Summer spawners do not migrate seaward in the spring, but school off the mouths of tributary streams used for spawning. Sometime between late June and the end of July they enter these streams and distribute themselves on spawning grounds. In 1981 this movement occurred between late June and early July. Anglers experienced good success sport fishing for char at the mouth of the Nimiuktuk River on June 28 (Bernd Gaedeke pers. comm.) but only six fish were observed in that area from the air on July 2. On July 5, an aerial survey showed char distributed in the lower 22 miles of the Nimiuktuk River. Observations on July 2 showed no char at the mouth of the Kugururok River and only few at the mouth of the Kelly River. On July 3, char were observed in the vicinity of spawning grounds on the Eli River, 68 miles from its mouth. Local reports indicate that char are usually available to anglers at Noatak tributary mouths until mid-July. June of 1981 was unusually dry, rendering the Noatak River very low and clear when I arrived in the study area on July 2. Low water conditions may have been responsible for the early movement of char into spawning streams. After spawning most summer spawners move into the Noatak River where they mix with the in-migrating overwintering segment of the population. The non-spawning overwintering population may be comprised of immature, 51 Table 2. Number of char tagged in the study area by year. sex. type and location. Kelly R. Kugururok Nimiuktuk Kivalina Wulik River Omar River M/F * 1980 1981 1981 1981 1980 1981 1980 1981 1980 F S 76 265 210 229 5 4 18 15 3 M S 21 93 83 112 4 10 6 2 U S 1 F 0 132 M 0 78 U a 62 Total Tagged 98 358 293 341 -9- 276 2"8 31 -5- V1 N M = Male F = Female U = Unknown * = S/Spawner a/Overwintering developing and non-consecutive spawning individuals. Spent fish were captured intermixed with newly-arrived overwintering fish on September 19, 1979 at the mouth of the Kugururok River. Spent and overwintering char were also observed in subsistence catches at Noatak village on September 30, 1981. Some summer spawners which spawn early probably migrate to sea for a month or two after spawning. This was indicated by the recovery of two char in the Kotzebue Sound commercial salmon fishery which were tagged as spawners in the Nimiuktuk River in early July. Both were recovered off the mouth of the Noatak River, one on July 28, 20 days after tagging and the other on August 8, 48 days after tagging. No information on sexual condition was available. Fall spawners enter the Noatak River with the first group of overwintering char in mid-August. It is not yet known when these fish enter spawning streams or how much overlap there is with summer spawning, but a prespawning female was captured 20 miles up the Kugururok River on September 17, 1979. This fish had an egg diameter of 4 mm and, judging by its silvery color, had just recently entered fresh water. Fall spawners may remain in spring areas after spawning or may move into the main Noatak. Partially spent char were observed in a spring area above newly-building aufeis on Trail Creek on October 5, 1981. There may not have been enough flow through the aufeis to allow later passage of these fish out of this spring area. Wulik/Kivalina Rivers: Alt (1978) reported movements of spawners on the Wulik and Kivalina Rivers similar to those described above for the Noatak River. Between August 8-11, 1981, fall spawners were moving up the Wulik River between Tutak Creek and the mouth of Ikalukrok Creek. Fifteen char were captured on hook and line. The two examined had eggs over 3 mm in diameter, were silvery in color, had a slightly distended vent and light pink spots. The fish which were tagged and released were similar, with the males having darker spots and beginning to develop kypes. These fish would probably not spawn until September. At this time summer spawners were actively spawning and non-spawning overwintering fish had not yet entered the Wulik. Overwintering Movements Noatak River: Arctic char destined to overwinter in the Noatak River begin entering the river in mid-August. Incidental char catches in the Kotzebue commercial salmon fishery indicate that the presence of char peaks in Kotzebue Sound during the third week of August. Sport fishermen caught overwintering char at the mouth of the Kelly River on August 21, 1981 and at the mouth of the Kugururok River on August 22, 1981. Bob Uhl (pers. comm.) indicated that there is an additional peak in-movement during mid-September in some years. In any event, the fall in-migration is prolonged, as four char were taken in one net night in Kotzebue Sound on September 25, 1979 (DeCicco unpublished). Timing of spring outmigration on the Noatak has not yet been determined. 53 Wulik/Kivalina Rivers: Alt (1978) reported four overlapping runs of overwintering char into the Wulik and Kivalina Rivers, with the size of fish increasing in subsequent runs and the in-movement extending from early August until after freeze-up. On August 20, 1981 overwintering char were as far upriver as Kili Hill (13 mi) on the Kivalina River and Avenak Mountain (12 mi) on the Wulik River. Out-migration takes place in the spring soon after the river breaks up. Spawning Noatak River: Arctic char spawning takes place in the Noatak drainage over a prolonged period, with fish being observed in the vicinity of spawning grounds from early July to mid-October. I have designated two groups of spawners. Summer spawners are those char which after overwintering remain in fresh water, move into tributary streams and occupy spawning grounds from early July through mid-September. Fall spawners are those char which in-migrate with overwintering fish in the fall and remain in tributary streams to spawn from mid-September through freeze-up. Surveys to locate spawning areas and enumerate summer spawners in the Noatak were flown during July and August. Arctic char spawning was observed in the Eli River, an unnamed creek below Kelly River, and in the Kelly, Kugururok, Nimiuktuk and Anisak Rivers. Table 3 presents aerial observations of spawners made in 1981. The highest total counts were 2,589 spawners in the Kelly River system and 3,284 in the Kugururok River system. A complete survey of the Nimiuktuk River was not accomplished due to high, turbid water during most of the spawning season. Counts in Table 3 do not represent an exact number of spawners in any of these systems due to movement into and out of spawning areas throughout the spawning period, but can be considered as an index of summer spawning for comparative purposes. Fall spawners were observed on October 5, 1981 in four spring areas on the Kugururok River. Only one of these areas had been used for summer spawning. Other areas used for summer spawning were devoid of fish at this time. Figure 2 shows known spawning and overwintering areas in the Noatak system. Most documented Arctic char spawning areas in northern Alaska are very closely associated with ground water sources (Yoshihara 1973, McCart 1980, Bendock 1981). Although there are many spring areas in Noatak spawning streams, and some spawning has been observed in and around springs, most spawning occurs downstream of springs in the main channels of streams. The major spawning streams maintain a limited flow throughout the winter (Childers and Kernodle 1981) and should be considered under spring influence for much of their length. Childers and Kernodle found no late winter flow in the Noatak River above the Kugururok River (mile 120). However, the Nimiuktuk River, entering the Noatak 77 miles above the Kugururok, does maintain some winter discharge 54 Table 3. Aerial observation of spawning char in the Noatak drainage. Tributary /I Char Stream to: Date Conditions Observed Kagvik Creek Kugururok R. 7/25/81 poor 317 Nunaviksak Creek Kurururok R. 7/25/81 poor 38 Kugururok River Noatak R. 7/25/81 poor 553 Unnamed Creek Noatak R. 7/26/81 good 193 Seagull Creek Nimiuktuk R. 8/16/81 poor 194 Kukakpilak Creek Nimiuktuk R. 8/16/81 good 361 Tumit Creek Nimiuktuk R. 8/16/81 good 853 Seagull Creek Nimiuktuk R. 8/17/81 good 606 Upper Nimiuktuk Noatak R. 8/17/81 fair 202 Trail Creek Kugururok R. 8/17/81 good 419 Nunaviksak Creek Kugururok R. 8/17/81 good 317 Kagvik Creek Kugururok R. 8/17/81 good 792 Kugururok River Noatak R. 8/17/81 good 1,756 Wrench Creek Kelly R. 8/19/81 fair 1,005 No Name Creek Kelly R. 8/19/81 fair 356 Avan River Kelly R. 8/19/81 fair 346 Kelly River Noatak R. 8/19/81 fair 882 55 ~ At l ~ ~ Spawning Areas (§;> Overwintering Areas 10 o 10 20 30 40 I 10 0 10 20 30 40 50 KILOMETERS I I I I Figure 2. Known spawning and overwintering areas in the Noatak system. and is the furthest upstream tributary on the Noatak where large numbers of spawning char have been found. An aerial survey in August 1980 revealed some char spawning in the Anisak River, which enters the Noatak 45 miles above the Nimiuktuk. Spawning was restricted to one spring area and only 18 fish were observed (Alt 1981). Bernd Gaedeke (pers. comm ,) indicated having caught Arctic char spawners in the vicinity of tributary streams located 400 miles up the Noatak River. Wulik/Kivalina and Coastal Waters: Spawning char were also observed in the Kivalina and Wulik Rivers and in some coastal streams between Kivalina and Cape Krusenstern. On July 26, 1981, three char were observed in Rabbit Creek, 12 in Jade Creek and 114 in the Omikviorok River. An aerial survey of the Kivalina River on August 20, 1981 showed 106 spawners in Grayling Creek, 331 in the braided fork of the Kivalina River, 51 in Baqhalik, and 40 in the Kivalina below the forks. On September 25, 1981, 245 fall spawners were observed in Baqhalik. An aerial survey of the Wulik River on August 20, 1981 showed 44 char spawning in Sheep Creek, 89 in Ikalukrok Creek and 129 in the main Wulik. Large numbers of chum salmon present in the Wulik River made it difficult to differentiate char. Alt (1978) estimated that 3,000 to 4,000 char spawn in the Wulik and Kivalina Rivers. Figure 3 shows known spawning and overwintering areas on the Wulik, Kivalina, and Omikviorok Rivers. Overwintering Noatak River: Char overwinter in the mainstem of the Noatak River from below Noatak Village to at least as far upstream as the Kugururok River. The Noatak River between the Kelly and Kugururok Rivers was aerially surveyed on September 29. No counts could be made because of slush ice, but char were observed off the mouths of both streams and in concentrations at several locations between. On September 31, Noatak residents were catching overwintering char through the ice in front of the village and they indicated that char are caught all winter in an area from about 6 miles below the village to 7 miles above (Fig. 2). A survey flown on September 21, 1980 by the Commercial Fisheries Division enumerated 45,185 char between Noatak Village and the Kelly River (Frank Bird, pers. comm.). Wulik/Kivalina: An aerial survey of overwintering char flown on September 25, 1981 enumerated 101,826 char on the Wulik River and 45,355 on the Kivalina River. These counts compare with counts from past years (Alt 1981). An additional survey was attempted on September 29, 1981 but the lower Wulik was frozen at that time and shelf ice forming along the riverbanks obscured visibility and provided shelter for fish ( Fig. 3). 57 1 II I VI 00 G Spawning Area r-::~, ~~, Overwintering Area 5 o 5 10 KILOMETERS I I I I 5 o 5 10 MILES , I I , Figure 3. Known spawning and overwintering areas in the Wulik, Kivalina and Omikviorok Rivers. Observations of Juvenile Char Young-of-the-year char were first observed in the Kugururok River on July 25. During work on the Kelly River on 16 and 17 July, no young-of the-year were observed; thus, emergence probably began sometime between 17 and 25 July in the Noatak system. Young-of-the-year were observed on Trail Creek on July 28, and during the first week of August they were abundant in side channels and slow shallow areas along the length of Wrench Creek. Eight Age I and II juveniles captured in small tributaries of Wrench Creek in early August ranged in fork length from 85 to 127 mm , In July and October a sample of 47 juvenile and residual char (stream resident males which develop and spawn at a small size) from Trail Creek ranged in size from 46 to 253 mm and in age from young-of-the-year to 7 years. Seven of these were found to be developing or prespawning residual males and two were spent males captured in a spring area which contained anadromous spawners on October 10, 1981. Yoshihara (1973) used the presence of residual male char to help explain the differential sex ratio of spawning char in the Sagavanirktok River. Seven outmigrating char smolts were captured by a Commercial Fisheries Division chum salmon research crew in the lower Noatak River. They ranged in size from 126 to 141 mm and in age from 2 to 4 years. Table 4 summarizes smolt data. Biological Aspects Gill raker counts: The modal gill raker count from 109 overwintering char collected in the Kivalina River was 22, from 48 char collected in Kotzebue Sound was 23, and from 20 juvenile char collected from Trail Creek was 22 (Table 5). Pyloric caecae counts: Pyloric caecae collected from 20 juvenile char from Trail Creek ranged in number from 23 to 33 with a mean of 28.2 and a mode of 27. Sex ratios: The male to female ratio of 1,088 spawning Arctic char tagged in the Noatak River system was 1:1.53 (Table 6). Yoshihara (1973) found a male to female ratio of 1:1.29 for all spawning char in the Sagavanirktok River. He used a seine as capture gear for most of his samples, while rod and reel was the primary capture gear in the present study. In the Kivalina River, a male to female ratio of 1:1.87 was found in a sample of 129 overwintering char caught in one seine haul on September 21, 1981. Length Frequency: Spawning char on the Noatak ranged in fork length from 396 to 870 mm for males and from 425 to 724 mm for females (Table 7, Fig. 4). 59 Table 4. Char smolts captured on the lower Noatak, June 14, 1981. Fork Length (mm) Weight (gm) Sex Age 126 15.0 M 2 130 17.9 F 4 133 18.3 F 3 133 19.3 M 4 136 20.3 F 3 141 21.2 F 3 141 22.6 M 3 Table 5. Gill raker counts. Kivalina River Kotzebue Sound Trail Creek , Range 19-26 20-25 20-23 n 109 48 20 Mean 22.1 23.1 21.7 Mode 22 23 22 60 Table 6. Sex ratio of Arctic char spawners in Noatak River tributaries. Location Kelly R. Kugururok R. Nimiuktuk R. Sex Total Male 114 83 112 309 Female 340 210 229 779 Male: Female 1:2.98 1:2.53 1:2.05 1:2.53 Table 7. Length frequency of Noatak River spawners and Kivalina River overwintering char by sex. Fork Length Kelly R. Kugururok Nimiuktuk Kivalina (mm) MF MF MFMF Unknown 350 - 374 3 1 375 - 399 1 1 7 4 400 - 424 1 7 11 14 425 - 449 5 1 17 31 24 450 - 474 5 4 3 2 15 36 15 475 - 499 9 31 10 26 12 25 18 17 3 500 - 524 22 88 22 63 22 59 6 10 1 525 - 549 29 72 11 56 18 68 4 6 550 - 574 8 59 14 27 14 33 6 4 575 - 599 10 39 4 19 6 19 3 2 600 - 624 5 20 6 8 3 10 1 625 - 649 2 13 3 4 8 5 4 650 - 674 9 8 4 3 11 2 675 699 2 2 4 4 5 700 - 724 1 3 4 6 1 725 - 749 2 1 750 - 774 2 1 775 - 799 3 1 800 - 824 2 825 - 849 1 850 - 874 1 61 225 - 200 '"""'- 175 150- (f) (l) o 125 - E - 50 - 25 - .r--t.-, I' ~ a If 400 450 500 550 600 650 700 Fork Length (rnrn) 75 (f) OJ -0 50 ~ 4- 0 25 0 z 400 450 500 550 600 650 700 750 800 850 Fork Length (rnrn) Figure 4. Length frequency by sex of char tagged in the Noatak system. 62 Overwintering char tagged in the Kivalina River ranged in length from 311 to 648 mm (Table 7). Fecundity: Ovaries were collected from 10 female Arctic char in Tumit Creek on the Nimiuktuk River on August 16 and from 10 females from the Kugururok River on August 18. Fish ranged in fork length from 482 to 652 mm with a mean of 533 mm. The number of eggs per female ranged from 3,717 to 8,6]8 (Table 8). Fecundity of Noatak River char was compared to that of comparably sized North Slope char from the Sagavanirktok River (Yoshihara 1973). Thirty-two Sagavanirktok char ranged in fork length from 483 mm to 630 rom with a mean of 519 mm. The number of ova per female ranged from 3,112 to 6,226. The mean fecundity for Noatak River spawners (5,696) was significantly higher than that of Sagavanirktok fish (4,532), (t=3.69; p 0.01). Kobuk River Char: Anadromous Arctic char occur in the Kobuk River. On June 13, 1978 Alt (unpublished) captured five out-migrating char smolts in Melvin channel on the lower Kobuk River. Village residents of Ambler and Kiana report taking char in early summer on hook and line and in subsistence nets near the mouths of the Ambler and Squirrel Rivers. They indicate that char are running into the Kobuk River from these tributary streams and are destined for the ocean. They also report taking fresh-run in-migrating char in the fall at these same locations. John Cooper (per s , commv ) observed the capture of two prespawning male char 60 miles up the Ambler River in August of 1976. He indicated that these brightly colored fish weighed 4 to 5 pounds and had pronounced kypes. Judging by their size, these were probably anadromous char. Jerry Covey (per s , commv ), a Kobuk resident, stated that a few char are taken on sport gear each year in Akpilak, Killak and Dahl Creeks, small Kobuk tributaries. Small-stream resident char, called "Old-man fish", have been reported in Dahl Creek by Kobuk residents. Ken Alt (pers. comm.) indicates that some large sized anadromous char are taken by Kobuk residents in the fall above Kobuk village during subsistence seining for sheefish and whitefish and that sport anglers also take some in this area of the main Kobuk. Char to 8 pounds have been captured. In 1968 two tagged char were recovered at Noorvik, both of these fish were tagged by Commercial Fisheries Division in Kotzebue Sound, one in 1967 and one in 1968. These reports, coupled with Division of Commercial Fisheries aerial surveys on the Squirrel River which indicated large concentrations of char in August, led us to believe that there was a sizable population of char in the Kobuk River system. On August 28, 1980 an aerial survey of the Squirrel River system was conducted and only 54 char were observed. In order to confirm low aerial counts, the Omar River, where 20 char were observed from the air, was floated in early September 1980. Twenty-nine char were observed while floating and walking side channels; of these, five were captured and tagged. While on the Squirrel River below the Omar several large schools of humpback whitefish were observed. These may have mistakenly been reported as char by Commercial Fisheries Division surveyors. In August 1981, Commercial Fisheries Division salmon tag recovery crews 63 Table 8. Ova counts of 20 female Arctic char ovaries from the Noatak River drainage. Ovary Weight Ovum Number F.L. Weight (gm) diameter of (mm) (gm) Left Right Combined (mm) Ova Tumit Creek: 492 1125 90.0 97.1 187.1 3.7 4,780 497 1175 77 .3 108.0 185.3 3.8 3,717 501 1100 95.1 89.4 184.5 3.8 3,984 510 1175 104.9 122.9 227.8 4.0 4,886 516 1230 109.6 113.2 222.8 4,345 574 1700 184.5 173.2 357.7 4.0 6,475 577 1900 207.6 188.2 395.8 4.4 8,307 600 1925 227.0 251.3 478.3 4.7 8,618 640 2500 250.6 300.9 551.5 4.4 8,182 652 2500 283.4 305.9 589.3 4.6 8,014 Kugururok River: 482 1100 120.7 104.6 225.3 4.0 4,855 487 1060 81.0 95.5 176.5 4.0 4,200 490 1100 101.8 115.6 217.4 4.0 4,553 492 1150 112.0 95.5 207.5 3.7 5,304 495 1175 128.5 108.0 236.5 3.7 6,465 510 1175 97.0 117.5 214.5 3.7 4,548 525 1300 108.9 100.3 209.2 3.8 5,172 525 1500 115.9 128.8 244.7 3.8 5,083 538 1450 160.9 146.4 307.3 4.2 5,975 560 1625 167.8 165.2 333.0 3.9 6,451 64 floated the Salmon and Squirrel Rivers. No char were observed on the Salmon River and only a few were seen on the Squirrel. Due to the apparent low incidence of char on the Kobuk, as compared to other rivers in the study area, and our limited budget and manpower, I am recommending that the Kobuk River no longer be included in the study plan for this project. If money and time become available at some future date, Arctic char investigations might be considered for the Kobuk, but at this time I feel our efforts should concentrate on the Noatak, Wulik, Kivalina and coastal streams where char are more abundant and more important to both subsistence and sport users. Utilization Noatak River: The major use of Arctic char within the study area is for subsistence. Fall seining takes place on the Noatak River by residents of Noatak. In 1981 four groups of people seined a total of 123 sacks of char. Their estimates of the number of fish per sack varied between 40 and 200, depending on fish size. At 100 fish per sack this would give an estimated fall harvest of 12,300 char. In addition to seining, Noatak residents fish through the ice in the vicinity of the village all winter long. On September 30, 1981, 15 people were observed fishing in front of the village. Two women fished 5.5 hours each and caught 24 and 26 char respectively, or approximately five fish per hour. Kotzebue residents also subsistence fish for char on the Noatak River in some years, but no harvest data are available. Local and non-local sportsmen fish char at the mouths of Noatak tributary streams and area fishing guides bring clients to the Kelly and the Nimiutuk Rivers. In 1981 two guided anglers captured about 60 char on the Kelly River, retaining six for personal use (Phil Driver pers. comm.). Wu1ik/Kivalina River: A1t (1981) estimated the annual average subsistence harvest for the village of Kivalina at 30,000 fish. The majority of these fish are taken by fall seining in overwintering areas. In 1981 only two boats got upriver to seine due to early freeze-up. It is estimated that the 1981 fall take of 15,000-18,000 was lower than in previous years. In 1979 an estimated 30,000-35,000 char were taken in fall seining by four groups (boats) of seiners. Usually when early freeze-up prevents seining, people from Kivalina make winter trips by snow machine to open water areas of the Wu1ik and seine char. Some winter ice fishing also occurs. See A1t (1981) for general utilization trends in northwestern Alaska. LITERATURE CITED Alt, K. T. 1978. Inventory and cataloging of sport fish and sport fish waters of Western Alaska. Annual report of progress, Federal Aid in Fish Restoration, 1977-1978, Project F-9-10, 19(G-I-P). 65 1981. Inventory and cataloging of sport fish and sport fish waters of Western Alaska. Annual performance report, Federal Aid in Fish Restoration, 1980-1981, Project F-9-13, 22(G-I-P). Bendock, T. N. 1981. Inventory and cataloging of Arctic area waters. Annual performance report, Federal Aid in Fish Restoration, 1980-1981, Project F-9-13, 22(G-I-I). Childers, J. M. and Kernodle, D. R. 1981. Hydrologic Reconnaissance of the Noatak River Basin, Alaska, 1978. U.S. Geological Survey Water Resources Investigations open-file report 81-1005. McCart, P. J. 1980. A review of the systematics and ecology of Arctic char, Salvalinus alpinus, in the Western Arctic. Canadian Technical Report of Fisheries and Aquatic Sciences No. 935. Sarrio, R. and Kessel B. 1966. Human ecological investigations at Kivalina. In "Environment of the Cape Thompson Region, Alaska" Edited by N. Wilimousky and J. Wolfe. U.S. Atomic Energy Commission. pp. 969-1040. Winslow, P. 1969. Inventory and cataloging of sport fish and sport fish waters in Interior Alaska. Char in Northwestern Alaska. Alaska Dept. Fish and Game. Federal Aid in Fish Restoration, Progress Report, 1968-1969, Project F-9-1, 10(16-A). Yanagawa, C. 1969. Kotzebue chum salmon tagging project 1966-1968. Fishery Bulletin #7, AYK Region, Alaska Dept. of Fish and Game, Anchorage. Yoshihara, H. T. 1973. Monitoring and evaluation of Arctic waters with emphasis on the North Slope drainages. Alaska Dept. of Fish and Game. Federal Aid in Fish Restoration, Annual Progress Report, 1972-1973, Project F-9-5, 14(G-III-D). Prepared by: Approved by: Alfred DeCicco Richard Logan, Ph.D, Fishery Biologist Director, Sport Fish Division Mark C. Warner, Ph.D Sport Fish Research Chief 66 Volume 23 Study No. G-I-P-B STATE OF ALASKA Jay S. Hammond, Governor Annual Performance Report for INVENTORY AND CATALOGING OF SPORT FISH AND SPORT FISH WATERS OF WESTERN ALASKA Part B: Innoko River and Sheefish Adaptability Studies by Kenneth T. Alt ALASKA DEPARTMENT OF FISH AND GAME Ronald O. Skoog, Commissioner DIVISION OF SPORT FISH Richard Logan, Director Volume 23 Study No. G-I RESEARCH PROJECT SEGMENT State: ALASKA Name: Sport Fish Investigations of Alaska Project No.: F-9-14 Study No.: G-I Study Title: INVENTORY AND CATALOGING Job No.: G-I-P-B Job Title: Inventory and Cataloging of Sport Fish and Stort Fish Waters of Western A aska Cooperator: Kenneth T. Alt Part B: Innoko River and Sheefish Adaptability Studies. Period Covered: July 1, 1981 to June 30, 1982 ABSTRACT Results are presented of the first year of a 2-year study of the fish of the Innoko River drainage. Emphasis the first year study was on sheefish, Stenodus leucichthys (GUldenstadt), movements. Sheefish were present near Shageluk Eddy on the Innoko River by late May. Sampling throughout the remainder of the summer captured sheefish from the Innoko River mouth upstream to the mouth of Dishna River. Fish captured included prespawning, non-spawning and immature fish. No prespawning fish were captured or observed in the upper Innoko River above Dishna River. Spawners may leave the Innoko and enter the Yukon River via Shageluk Slough, as one of 58 sheefish tagged in the Innoko was recovered 3 months later migrating up the Yukon River. Considerable information on food habits, age and growth, and distribution of Innoko River sheefish was collected during 1981 but will be reported on at the conclusion of the 2-year study in 1982 (1983 publication). Addi tional information on life history and ecology of broad whitefish, Coregonus nasus (Pallas), humpback whitefish, Coregonus pidschian (Gmelin), least cisco, Coregonus sardinella (Valenciennes) and northern pike, Esox lucius Linnaeus was collected and will be reported on later. Utilization of sheefish, pike, and whitefish in the Innoko is mainly for subsistence by Shageluk and Holy Cr.oss residents. Recreational use is presently low. Results of an ongoing sheefish adaptability study are presented. Sheefish at the newly constructed Clear Hatchery were successfully reared to finger ling size in 1981. Fingerlings were stocked in Silver Fox Pit, Weigh Station Ponds, Craig Lake and Lakeview Pond. Lakeview Pond fish averaged 130 mm after 6 months stocking. Fry were stocked in five additional lakes and ponds in the Fairbanks-Delta Junction area. The capture of an Age III mature female and Age II mature maies in Eielson Cooling Pond represents the youngest age at maturity for sheefish in Alaska. KEY WORDS Sheefish, stenodus leucichthys (GUldenstadt), interior Alaska, Innoko River, movements, use, hatchery sheefish. BACKGROUND Preliminary surveys of the lower Innoko River in late June 1979 indicated the presence of large numbers of sheefish. With completion of sheefish research in the Kuskokwim system in 1980, it was decided to undertake a 2-year sheefish research proj ect on the Innoko River, but to include a basic stream survey and collect biological information on other species inhabiting the Innoko, especially whitefish and pike. With the consider able time and effort devoted to other species it was decided to change the proj ect title from R-II to G-I-P (Catalog and Inventory). Basic life history studies of sheefish in other drainages in Alaska, as well as most of the Yukon River have been completed and published. Population status of sheefish in the Yukon River is fairly well understood. The majority of sheefish in the Yukon River in Alaska belong to a large anadromous popula tion which overwinters in the lower Yukon River, including the brackish water environment. Spawning occurs in the Koyukuk and Alatna Rivers and upstream of the Dalton Highway bridge across the Yukon River. There are numerous small local populations both within and outside the range of the anadromous population (Nowitna River, Minto Flats, upper Yukon River, upper Porcupine Rivet). It is not known if the Innoko River sheefish constitute a separate local population similar to Nowitna River sheefish or if the Innoko is another spawning area for the anadromous lower Yukon population. Another possibility is that the Innoko River is simply a feeding stream for sheefish of the lower Yukon population, with fish later in the summer taking part in the upstream spawning migration in the Yukon River. Deter mining patterns of movement and population status of Innoko River sheefish will be the main emphasis of this 2-year study. Life history information on pike and whitefish will also be collected. Figure 1 depicts the Innoko River drainage. Table 1 lists the common and scientific names and abbrevi ations of fish found in the study area. RECOMMENDATIONS Research 1. To continue the second year of the Innoko River sheefish study under a catalog and inventory study and concentrate efforts on pike and whitefish, as well as sheefish. 2. To complete the physical survey of the Innoko River system. 68 ~ K I Fig. 1. Innoko River study area. 69 Table 1. List of common names, scientific names, and abbreviations of fish found in study area. Common Name Scientific Name and Author Abbreviation Arctic char Salvelinus alpinus (Linnaeus) AC Arctic grayling Thymallus arcticus (Pallas) GR Broad whitefish Coregonus nasus (Pallas) BWF Burbot Lota Iota (Linnaeus) BB Chinook salmon Oncorhynchus tshayrytscha (Walbaum) KS Coho salmon Oncorhynchus kisutch (Walbaum) SS Chum salmon Oncorhynchus keta (Walbaum) CS Humpback whitefish Coregonus pidschian (Gmelin) HWF II Inconnu (sheefish) Stenodus leucichthys (Guldenstadt) SF Lake chub Couesius plumbeus (Agassiz) LC Lake trout Salvelinus namaycush (Walbaum) LT Least cisco Coregonus sardinella (Valenciennes) LCI Longnose sucker Catostomus catostomus Forster LNS Northern pike Esox lucius Linnaeus NP Round whitefish Prosopium cylindraceum (Pallas) RWF Slimy sculpin Cottus cognatus Richardson SSC 70 3. To search for spawning grounds of sheefish and whitefish in the Iditarod River. Management 1. To survey fishing utilization and sport fishing potential of the Innoko River system. OBJECTIVES 1. To stock various lakes and ponds in interior Alaska with sheefish fry and fingerlings. 2. To evaluate success of past sheefish plants. 3. To survey new waters for experimental stocking. 4. To determine movements, run timing and distribution of sheefish in the Innoko River system. 5. To collect basic life history information, especially age and growth and food habits, from Innoko River sheefish. 6. To locate Innoko River spawning grounds and collect data on spawning ecology of Innoko River sheefish. TECHNIQUES USED Innoko River surveys were conducted by riverboat from Fairbanks with supply points at Galena and Grayling. A raft was used to float the extreme upper reaches of the Innoko River in late September. Fish were collected by gill net, seine and hook and line. Sampling was conducted in the main river and interconnected lakes and sloughs. Scales were collected for aging from all species except char, for which otoliths were used. C1eithrum bones were collected for pike aging. They were cleaned of skin and meat, and the annular rings were read using low mag nification or held up to the light and read without magnification. Char gill rakers and pyloric caecae were counted in the field. Sex and maturity of fish were determined through gross examination of the gonads. Sheefish were tagged with orange spaghetti tags. Rewards for returned tags were paid by the Division of Commercial Fisheries. Information on fish utili zation, distribution, and abundance, as well as insight into stream characteristics was obtained through conversation with residents of McGrath, Shageluk, Ruby and Holy Cross. Egg takes and sheefish stocking were conducted in cooperation with the F.R.E.D. Division of Alaska Dept. of Fish and Game. Fry and fingerlings were placed in well-oxygenated plastic bags filled with chilled water. Transport was by vehicle and backpack. 71 FINDINGS Innoko River Study Movements: Summer Movements. Preliminary movements of sheefish in the Innoko River were determined by test netting, discussion with local residents and a tag and recovery program. Sheefish were already present at the mouth of Holikachuk Slough and Shageluk Eddy by May 23. The feeding sheefish included both potential spawners and non-spawners. Greatest abundance at this time was correlated with the downstream migration of chum salmon fry on May 28-29. The few fish caught in test net sites in the lower Innoko drainage (Red Wing Slough, Paimiut Slough, Reindeer Lake) on May 25-27 indicated that the movement into the Innoko had probably occurred prior to this time. The catch of 0.7 sheefish per net night in the lower Innoko contrasted with 17 sheefish per net night at Shageluk Eddy (Table 2). In mid-June sheefish were still feeding in the area of Shageluk Eddy. They were smaller than fish taken in May. Sheefish were also feeding in the Innoko River 8-12 miles upstream of Holikachuk and in the lower Iditarod River in mid-June. In late August and early September test netting indicated presence of a few sheefish at Holikachuk Slough mouth, Iditarod River mouth, lower Iditarod River and Dishna River mouth, but none further upstream. Except for two prespawning males in the lower Iditarod River all fish were non-spawners. Test net data did not indicate a spawning migration to the upper Innoko even though residents familiar with the upper river mentioned capturing sheefish in the upper Iditarod near Flat, and in the Innoko River near Cripple, Folger Creek and North Fork Innoko in late September and October. The fish were possibly summer feeders, as none of the informants recalled seeing large-sized eggs. Spawning Movements. Prespawning sheefish were present at the mouth of Holikachuk Slough and at Shageluk Eddy by May 24. Spawners evidently enter the Innoko River with non-spawners during breakup or may possibly over winter in the Innoko River. Percentages of spawners of fish captured in the Innoko River during 1981 included 56% in May, 73% in June and 14% in August and September (Table 3). No spawning fish were captured further upstream than the lower Iditarod River. Interstream Movement. There is some movement of sheefish between the Innoko River and the Yukon River. A tagged sheefish was recovered on the Yukon River 18 mi below Ruby on August 26. This was the only recovery of sheefish tagged on the Innoko in 1981 out of 58 fish tagged. The fish was tagged on May 30 on feeding grounds at Shageluk Eddy. The larger size of fish tagged in late May (xFL = 709 mm, n=20) vs the 692 xFL (n=30) tagged in mid June indicates that some spawning fish may have moved further up the Innoko or back down into the Yukon before continuing on their migration to spawning streams. 72 Table 2. Test net results in the Innoko River and tributaries, 1981. Net Species Captured Location Date Nights SF HWF BWF LCI NP CS SS GR Others Mouth Holikachuk Sl 5/24 2 3 2 8 4 10 Holikachuk Lake 5/24 1 6 2 8 Shageluk Eddy 5/25 2 3 24 72 53 25 1 BB Lake Slough below Shageluk (A) 5/26 2 10 6 1 16 Lake Slough below Shageluk (B) 5/26 2 4 2 2 Innoko R. mouth 5/27 1 2 1 Railroad City Slough 5/27 1 1 4 4 8 Mouth Paimute Slough 5/27 1 2 2 1 Reindeer Lake Slough 5/28 2 6 4 4 10 Paimute Slough 5/28 3 2 2 Shageluk Eddy 5/29 2 2 4 1 28 Shageluk Eddy 6/13 2 4 2 1 1 2 5 2 Mi up Iditarod R. 6/16 3 1 36 9 4 15 1 Iditarod R. mouth 6/16 4 10 4 24 1 1 LNS Mou th Ho likachuk S1. 6/18 2 3 6 1 9 Shageluk Eddy 6/19 2 5 1 30 1 KS Holikachuk SL, Mouth 8/30 2 5 2 AC 1 LNS Iditarod R. Mouth 8/30 4 4 3 14 1 2 Mi up Iditarod R. 9/1 2 2 4 10 15 1 Innoko R. @ Hather Creek 9/2 2 2 7 20 Hather Creek 9/2 1 5 Dishna R. Mouth 9/3 3 2 1 1 29 23 Innoko R. @ N. Fork 9/4 1 17 7 North Fork Innoko 9/4 1 3 3 Innoko 10 mi above N. Fork 9/5 3 2 6 6 13 Innoko R. Cripple Area 9/7 2 3 3 4 8-20 Mi up N. Fork 9/8 4 2 2 13 1 RS Innoko Above N. Fork 9/9 4 11 13 17 17 1 AC Innoko Above Cripple 9/10 4 13 26 6 29 2 1 LNS Innoko @ Beaver Cr 9/29 1 7 9 1RWF Innoko R. 40 mi below Ophir 9/30 1 1 2 Innoko R. Folger Creek 10/1 1 3 2 1 4 2 Innoko R. 8 mi above Cripple 10/2 1 3 4 1 3 3 1 LNS 73 Table 3. Sex and maturity of sheefish captured in the Innoko River, 1981. Sampling Sex and Period No. Maturity Location May 1 M-* Developing Holikachuk Slough 2 M - Spawner Shageluk Eddy 1 M- Spawner Innoko R. at Holikachuk 1 M- Spawner Shagaluk Slough Eddy 1 M - Spawner Mouth of Redwing Slough 1 F - Developing Shageluk Eddy 1 F - Developing Innoko River at Holikachuk 1 F - Redeveloping Shageluk Eddy Mid June 7 M- Spawner Shageluk Eddy 2 M- Spawner Holikachuk Slough Mouth 1 M- Spawner Lower Iditarod River 2 F - Developing Shageluk Eddy 1 F- Spawner Shageluk Eddy 1 F - Redeveloping Shageluk Eddy 1 F- Developing Holikachuk Slough Mouth Late Aug.-Sept. 2 M- Developing Innoko River at Iditarod 1 M - Developing Innoko River at Dishna 1 M- Spawner 2 mi up Iditarod River 1 F- Developing Innoko River at Iditarod River 1 F- Redeveloping Innoko River at Iditarod River 1 F- Redeveleoping 2 mi up Iditarod River Total: 20 Males (16 Spawners 4 non-Spawners) 11 Females ( 1 Spawner 10 non-Spawners) Summary: May 5 out of 9 (56%) prespawners June 11 out of 15 (73%) prespawners Aug.-Sept. 1 out of 7 (14%) prespawners * M - Male F Female 74 Distribution: Based on 1981 test-netting results, sheefish are limited mainly to the mainstem Innoko River. Extensive netting was conducted in small lakes and sloughs of the Innoko below Holikachuk and no sheefish were captured (see Table 2). It appears that many of the smaller tributary streams e s g , , Grouch, Mud, Hather, Folger & Beaver Creeks, do not contain sheefish. They were, however, captured in the lower Iditarod River and more netting is planned for the upper Iditarod in 1982 to determine if spawning fish might use this area. Sheefish were captured at the mouth of the Dishna River but no nets were set further up this major tributary. Residents of McGrath familiar with the Dishna River had no knowledge of sheefish in this stream. Sheefish probably do not utilize the North Fork Innoko River, as none were taken during 4 nights of fishing. The stream did not appear suitable for sheefish. In spite of extensive netting in the Innoko River between Ophir and Dishna River (approx. 280 mi) no sheefish were captured. Large catches were made of coho salmon, pike, least cisco, and broad and humpback whitefish. Areas that appeared to have habitat suitable for sheefish spawning were found upstream and downstream of Folger Creek mouth. Trappers had reported capturing sheefish in the first pool area above Cripple Landing and at the mouth of the North Fork Innoko in October by net and near the mouth of Folger Creek in late September on hook and line. A guide operating a lodge at Cripple Landing featured sheefish fishing along with pike and grayling. Thus, sheefish are distributed at least in some years in the main Innoko up to the mouth of Folger Creek. It is not known if increased mining activity in recent years might have caused sheefish to cease their migrations to this upper area. People who had knowledge of sheefish presence in the upper Innoko could not positively identify the fish as spawners. Thus, fish reported may have been non-spawners. Age, Growth, and Food Habits: Data are still being collected and will be reported on in 1983. Utilization: During 1981 the utilization of sheefish in the Innoko River was quite small and consisted mainly of the Shageluk Village subsistence harvest, which the author estimates at less than 500 fish. The main body of sheefish gen erally migrate slightly later than the humpback and broad whitefish and are taken only in small numbers from late May through October. Whitefish and salmon are the target species for Shageluk residents. Sheefish are available for sport fishermen in various feeding areas located generally upstream of Shageluk to the Iditarod River. During 1981 all sheefish caught on rod and reel by survey crews were taken between the mouth of Shageluk and Holikachuk Sloughs in the Innoko River. Small numbers were taken by gill net from Holikachuk Slough upstream to the mouth of the Dishna River (220 mi) but, despite extensive hook and line effort, none were captured on sport gear. The sport harvest by Holy Cr8ss, Shage luk and Grayling residents is very low. Anglers from McGrath reported occasionally capturingsheefish on hook and line near Folger Creek in the 75 upper Innoko, and trappers reported capturing sheefish for dog food in the upper Iditarod River near Flat, at the mouth of the North Fork Innoko and in the main Innoko above Cripple. We captured no sheefish on hook and line in these upriver areas in September and early October. The upper Iditarod will be surveyed in 1982. The Iditarod and Innoko were extremely turbid from early June to October 5 and whether heavy mining activity has altered sheefish movements remains to be seen. Sheefish Adaptability Study 1981 Egg Takes: Egg take efforts in 1981 were directed mainly at the Koyukuk River above Hughes, but an experimental egg take was conducted in the Yukon River near the Ray River. Only two females were captured in the Yukon River and 90,000 eggs were taken from one female before abandoning the project. Ten females had already yielded 800,000 eggs at Hughes. In 1982 all sheefish eggs will be taken from Yukon River fish. It is believed that sufficient numbers of females can be captured by expanding the 1981 operation and arriving at the egg take site earlier in September. Hatching of eggs began in late December 1981 and was completed by January 15, 1982. Hatching success was 48%. 1981 Sheefish Stocking Silver Fox Pit: Silver Fox Pit, located 54 miles south of Fairbanks on the Richardson Highway, was stocked with 200 fingerlings on June 29. The lake has 2.5 surface acres and is 12 feet deep. The pit has a resident population of lake chubs. Water temperature on June 29 was 16o C. Fish stocked ranged in length from 36 to 52 mm and were in good condition. Mortality was estimated at 10% at stocking. Chubs immediately moved in to eat dead and weakened fish. The lake had previously been stocked with 10,000 fry in February of 1969, all were probably eaten by chubs as none were captured in subsequent sampling. Weigh Station Ponds: These two man-made ponds are located 6 miles south of Fairbanks on the Richardson Highway. North Weigh Station Pond is 2.6 acres in size, while South Weigh Station Pond is 1.8 acres. Both contain chubs. North Weigh Station Pond is 32 feet deep, while South Weigh Station Pond is 30 feet deep. On June 29, 320 fingerling sheefish were stocked in the north pond and 280 fingerlings in the south pond. Observed mortality was 10 fish in each pond. Gull Lake: Gull Lake is an 8-acre lake, 20 feet deep, located on the Ft. Greely Military Reservation. The lake has a sand and silt bottom and a rocky shoreline. Slimy sculpins are the only fish species present. Twenty thousand sheefish fry at 30,000/lb were stocked under the ice on January 19. 76 Sheefish were observed surfacing over the entire lake on July 26. Fish sampled on this date were 118 to 128 rom FL and were feeding on emerging Diptera adults. Eight sheefish were captured in a 25-foot gill net set overnight. Texas Lake: Texas Lake is a 20 acre lake located on the Ft. Greely Military Reser vation. This barren lake has a maximum depth of 18 feet. Fifteen thousand sheefish fry were stocked on January 19. A fyke net set overnight in August took no sheefish. t Manchu Lake: This 100-acre lake on Ft. Wainwright Military Reservation was stocked with 40,000 fry on January 19, 1981. It was not test netted in 1981. Eielson Cooling Pond: Eielson Cooling Pond was stocked with 10,000 fry on January 19, 1981. It had previously been stocked in 1977, 1978 and 1979. The majority of fish captured in subsequent years were from the 1977 plant. No fish of the 1978 plant and only two fish of the 1979 plant had been captured prior to 1981. Two sheefish were captured in 6 net nights of fishing, March 18, 1981. Both fish were females (527 and 522 mm) and both contained numerous loose eggs in their body cavities, indicating failure to spawn in the fall of 1980. In October 1981 five sheefish were captured during 2 net nights of fishing. One fish, 555 rom Age IV, was from the original 1977 plant; two fish, 595 and 515 rom females, Age III, were from the 1978 plant, and two fish, 500 mm and 566 mm males, Age II, were from the 1979 plant. The Age IV fish was a mature male, the larger Age III female was ripe, while the 515 mm fish was immature. Both Age II males were mature. This is the first recovery of sheefish from the 1978 plant of less than 1,000 fish. The recovery of Age II males in spawning condition is the youngest spawning age for males recorded in Alaska. All fish captured in October had empty stomachs. Lakeview Pond: Lakeview Pond is a barren, 30-acre man-made pond just south of the Fair banks city limits. Late winter 1980 dissolved oxygen reading of 4.5 ppm indicated that suitable conditions existed for stocking fish. On May 10, 1982 about 10,000 fingerlings (22-36 mm FL) were stocked. Twenty-two fish were caught in 4 net nights of fishing an experimental gill net set under the ice on Nov 11-12, 1981. Ten fish sampled ranged from 120-139 mm FL (x =130mm) and 14-20g (x =16. 3g) • Seven of the 22 fish had deformities of the jaw, including six short upper jaws and one shortened and offset lower jaw. Forty percent of the fish sampled contained Daphnia sp . in their stomachs, the only food item eaten. Craig Lake: Craig Lake is a 17-acre lake located 137 miles south of Fairbanks on the Alaska Highway. Maximum depth is 75 feet. The lake had been stocked with 77 coho salmon and rainbow trout from 1960-1974. Stocking was discontinued after lake chubs became established in the lake. A total of 3,400 sheefish fingerlings at 500 fish to the pound (FL = 30-56 mm) was stocked on June 29, 1981. Fish were in poor condition because of extensive time in transport. Three hundred dead fish were observed. South Greely Pond: South Greely Pond was stocked with 10,000 fry in February 1977. Sheefish were first captured in 1980 when 38 fish with a mean fork length of 444 mm were taken during 2 net nights of fishing. In 1981, 17 fish were captured on hook and line in 2 hours of fishing; all were released. Evaluation of new waters for stocking In 1981 Nenana Pond and Harding Lake were evaluated for future stocking. Nenana Pond is a 10-acre lake located 2 mi south of Nenana and adjacent to the Nenana River. The lake had previously been stocked with grayling and rainbow trout, but northern pike and suckers were carried into the lake by flooding. Sport fishing success has been very low the past 2 years and, since the Sport Fish Division has no plans to rehabilitate the lake, stocking of fingerling sheefish is contemplated. It is hoped that the fingerlings will survive in sufficient numbers to be effective predators on other species present. . Harding Lake: Harding Lake is a 2,470-acre lake located on the Richardson Highway, 45 miles southeast of Fairbanks. The lake has a mean depth of 53 feet and maximum depth of 142 feet. The fish population includes northern pike, burbot, least cisco, slimy sculpin and the introduced species lake trout and coho salmon. From 1963-1965, 500 adult lake trout were stocked. A few continue to be caught in Fish and Game Department test gill nets, but very few have been caught by anglers. From 1969-1978, 2.3 million coho salmon fingerlings were stocked in Harding Lake. The return to the anglers creels has been low. Thus, the main sport fish contribution of Harding Lake fish is pike caught on hook and line in the summer and speared through the ice in winter and burbot captured through the ice. Populations of least cisco have increased during the past 2 years as stocked coho salmon have com pleted their natural life cycle. In lake and river systems in Northwest Alaska, least cisco are the primary food source of sheefish. It is expec ted that stocked sheefish would utilize least cisco. Sheefish fingerlings, if available, would be stocked in mid-summer 1982. Prepared by: Approved by: Kenneth T. Alt Richard Logan, Ph.D. Fishery Biologist Director, Division of Sport Fish Mark C. Warner, Ph.D. ARLIS Sport Fish Research Chief Alaska Resources Library & Information Services Anchorage, Alaska 78