A Life History and Study of Sheefish and Whitefish in Alaska. Alaska

Volume 21

STATE OF ALASKA

Jay S. Hammond, Governor

Annual Performance Report for

A LIFE HISTORY STUDY OF SHEEFISH AND WHITEFISH IN ALASKA

Kenneth T. A1 t

ALASKA DEPARTMENT OF FISH AND GAME Ronald 0. Skoog, Commissioner

SPORT FISH DIVISION Rupert E. Andrews, Director Compiled and Edited by: Mark C. Warner, Ph.D. Laurie M. Wojeck, M.A. TABLE OF CONTENTS

STUDY NO . R-I1 A LIFE HISTORY STUDY OF SHEEFISH AND Page WHITEFISH IN ALASKA

Job No . R-11-A A Sheefish Lake and River Adaptability Study Job No . R-11-B Movements. Abundance. Population Dynamics. and Spawning Ecology of Sheefish and Whitefish in Interior and Arctic Alaska By: Kenneth T. Alt

Abstract ...... 1 Background ...... 2 TechniquesUsed ...... 3 Recommendations ...... 3 Literaturecited ...... 30

Job No . H-11-A

Objectives ...... 5 Findings ...... 5 1979Stocking ...... 5 EvaluationofPastPlants ...... 5 Comparitive Growth of Sheefish in Stocked Lakes 1969-1977 . . 9 Job No . R-11-B

Objectives ...... 10 Findings ...... 12 Test Netting Results .Lower Yukon River Tributaries .... 12 Lower Tanana River Sheefish Run Timing ...... 12 Search for Rearing Sheefish .Selawik Area ...... 16 Utilization Studies ...... 16 Life History of the Least Cisco in Alaska ...... 21

LIST OF TABLES AND FIGURES

Table 1. List of common names. scientific names. and abbreviations of fish found in study area ...... 4 Table 2. Average number of scale circuli to Age I for sheefish from various waters of Alaska ...... 8 Table 3. Growth of sheefish in waters stocked during sheefish lake and river adaptibility study ...... 11 Table 4. Sheefish catch statistics-. lower Yukon River tributaries June19.27. 1979 ...... 13 Table 5. Age-length relationships for sheefish from the lower Yukon River ...... 14 Table 6. Lower Tanana River test netting May 14.19, 1979 .... 15 TABLE OF CONTENTS (Cont'd.)

Figure 1. Selawik Lake area netting locations ...... 17 Table 7. Test netting results Selawik area May 29-June 6. 1979 . 18 Table 8. Gill raker counts of Alaskan least cisco ...... 23 Figure 2. Least cisco sampling areas ...... 24 Table 9 . Mean fork length at capture of least cisco from various Alaskan waters 1968-1979 ...... 25 Table 10. Mean fecundity for each 10 mm size group in the Chatanika River spawning population. 1972 ...... 27 Volume 21 Study No. R-I1

RESEARCH PROJECT SEGMENT

State: ALASKA Name: Sport Fish Investigations of A1 aska

Project No. : R-I1 Study Title: A LIFE HISTORY STUDY OF SHEEFISH AND WHITEFISH IN ALASKA

Job No.: R-11-A & R-11-B Period Covered: July 1, 1979 to June 30, 1980

ABSTRACT .. Sheefish, Stenodus leucichthys (Guldenstadt), fry stocked in Island Lake in May showed excellent growth and survival, but fry stocked in Eielson Cooling Pond experienced almost total mortality. Analysis of growth for lake-stocked fish during the first 10 years of the experimental program is presented. Fish stocked in barren lakes show rapid growth during early years, but subsequent growth slows rapidly. Heavy stocking of other species together with sheefish generally results in stunted growth for sheefish because of severe competition. Sheefish successfully spawned in Four Mile Lake in 1975, the first Alaskan record of lake spawning. An Age 111, 368 mm fish was captured by hook and line in August, 1979. Results of sheefish test netting in streams of the lower Yukon River are presented. Sheefish were most abundant in the Innoko River, and both immature and prespawning fish were taken. Surveys of waters in the Selawik and Selawik Lake areas failed to capture sheefish of Ages 0, I, 11, and 111, but rearing and spawning fish were captured in Selawik Lake, Selawik River, and the Tuklomarak River. Few sheefish were caught in lakes and sloughs in the study area. Patterns in sheefish recreational use in most waters continue t.o change toward heavier use by local residents. The Holitna River experi- ences the heaviest non-local pressure.

Life history data for least cisco, Coregonus sardinella Valenciennes, collected during the past 10 years of the sheefish-whitefish study are presented. ~en~rall~, -migrator; river populations grow fastest and attain the largest size. Dwarf lake populations and some anadromous populations are the slowest growing. Details of spawning for Chatanika and Kobuk River lEish are presented. Utilization of the least cisco is mainly for subsistence. BACKGROUND

Present thrust of the Sport Fish Division in the Lake and River Adaptabil- ity Study is to continue stocking sheefish in barren lakes, to survey new lakes for stocking, to evaluate success of past plants and to assist hatchery personnel in their role of taking eggs, and hatching and rearing fry.

Again in spring of 1979 considerable trouble was experienced at the hatchery in keeping sheefish fry alive until lakes were ice free. A new hatchery was to be completed at Clear Air Force Station in late 1979. However it is now doubtful whether it will be completed by late 1980. The Fire Lake Hatchery was closed down in May of 1979, thus the egg take for 1979 was canceled. Unless a new location for hatching the eggs can be found, the project will lose valuable momentum built up slowly during the past 12 years.

The feasibility of capturing wild fingerling sheefish and transporting them to small lakes containing prey species in the Fairbanks area will be investigated. This would allow evaluation of an important segment of the lake and river adaptability study to continue until successful hatchery rearing of fingerling sheefish can be accomplished.

Ongoing studies of patterns of sheefish utilization, as well as completion of life history studies in certain populations, will continue during the next 5 years. Basic sheefish surveys were conducted during this study and the discovery of a large population in the Innoko River calls for a complete study of this population to begin in 1981. This population is important because it appears to be large, has high sport fishing potential, and appears to have very light utilization. I feel that by promoting sport fishing use of this population, pressure may be reduced on more heavily fished populations in Alaska. Data for the population dynamics study of Holitna River sheefish have been collected during 1978 and 1979, and will continue through 1980. In addition to utilization studies and the Innoko River study, emphasis during the next 5 years will be on location of spawning grounds of Yukon River sheefish passing through Rampart and the location of secondary spawning grounds, if any, of Kuskokwim River sheefish. Work on abundance, run timing, and population status of wild stocks of sheefish in the Fairbanks area needs to be initiated, especially before proposed stockings of fingerling sheefish are made in rivers.

With the publication of life history data on least cisco in this report, the whitefish segment of the project will be temporarily discontinued. During the past 10 years basic life history information on the important whitefish species: least cisco (present report), Bering cisco (Alt 1973), broad whitefish (Alt 1976), humpback whitefish (Alt 1979), and whitefish of the Colville River (Alt and Kogl 1973) has been published in scientific journals as well as annual Federal Aid in Fish Restoration Reports. Future collection of whitefish data in conjunction with sheefish research will continue, and data will be published on an intermittent basis or in catalog and inventory studies. Table 1 lists common names, scientific names and abbreviations of fish mentioned in this report.

TECHNIQUES USED

Sheefish were captured during the present study by gill net, fyke net, and hook and line. Measurements were taken according to standard techniques. Age determination was by scale analysis, with scales mounted between glass slides and read with an Eberback projector. Maturity was determined through gross examination of the gonads in the field. Fish were considered mature if they would spawn the current fall, but were termed mature-non- consective spawners if they had spawned previously and would not spawn during the present year. Information on utilization was collected during spot checks of important fisheries, but mainly through conversation with local residents. Least cisco data were collected during the past 10 years in conjunction with the sheefish life history study and catalog and inventory studies. Chatanika River spawning information was collected during a joint Department of Fish and Game and University of Alaska graduate study.

RECOMMENDATIONS

Research--

! Evaluation of past sheefish plants should be continued.

2. New ponds and lakes in the Fairbanks area should be surveyed for stocking potential.

3. Feasibility of stocking wild fingerlings in local ponds containing prey species should be investigated.

4. The population dynamics study on the Holitna River should be completed.

5. A 2-year study of Innoko River sheefish should be initiated.

6. The whitefish life history study should be temporarily discontinued.

Management

1. Harvest checks on major sheefish fishing areas should be continued.

2. Public use of stocked sheefish lakes should be monitored.

3. Angling for Innoko River sheefish should be promoted. Table 1. List of common names, scientific names, and abbreviations of fish found in study area.

Common Name Scientific Name and Author Abbreviation

Broad whitefish Coregonus nasus (Pallas) BWF

Burbot --Lota lota (Linnaeus) BB Chinook salmon Oncorhynchus tshawytscha (Walbaum) KS

Coho salmon Oncorhynchus kisutch (Walbaum)

Grayling Thymallus arcticus (Pallas)

Humpback whitefish Coregonus pidschian (Gmelin)

Lake chub Couesius plumbeus (Agassiz)

Least cisco Coregonus sardinella Valenciennes

Northern pike Esox lucius Linnaeus NP

Rainbow trout Salmo gairdneri Richardson

Sheef ish Stenodus leucichthys (Guldenstadt) SF

Smelt Osmerus mordax (Mitchell) RSM

Sucker Catostomus catostomus (Forster) LNS Job R-11-A A Sheefish Lake and River Adaptability Study

OBJECTIVES

1. To interim rear sheefish to fingerling size and to stock various lakes and streams in Interior Alaska.

2. To evaluate success of past plants.

3. To survey new waters for experimentation.

FINDINGS

1979 Stocking

Ten thousand sheefish fry were stocked in Eielson Cooling Pond on March 20, 1979. The fry had just hatched and were in good condition. Water temperature was 47OF. Six hundred fry were placed in screened pens and the remainder were released into the pond.

Nineteen sheefish were stocked through the ice in Walden Pond on March 16. The fish were netted from Eielson Cooling Pond and were all Age 11.

On May 3, 15,000 sheefish fry were stocked in Island Lake. These fry had hatched in the Fire Lake Hatchery in March. The fry were feeding, but not growing, and in very poor condition when stocked. An estimated 10-20% of the fish were dead.

Evaluation of Past Plants

Island Lake:

Island lake is a nearly circular lake 50 a in size, located at 2,100 ft elevation in the Donnelly Flats approximately 25 mi south of Delta Junction. The lake is about one-third mile east of the Richardson Highway, and one-forth mile north of the Trans-Alaska pipeline.

The western part of the lake is quite shallow, 0.5 to 4 ft, while the eastern part is deeper and had a maximum winter depth of 18 feet. The shallow and deep sections are partially separated by an island. The shore vegetation is grass and tundra. Submergent and emergent vegetation is present in the shallow areas. The open lake is subject to strong year- round winds from the south. The lake is generally windswept in the winter, with ice thickness up to 5 feet.

In 1!376, the lake was judged suitable for sheefish stocking after winter dissolved oxygen readings were recorded at 8 ppm on April 2. Gill nets set in June of 1976 took no fish, indicating the lake was barren. Water temperature was 57OF on June 23. Aquatic insects and crustaceans, especially --Gammarus were very abundant. Island Lake ice was only partially melted on May 3, 1979 when sheefish were stocked in the shallow western part of the lake. Water temperature was 39OF. Predaceous insects of the family Notonectidae were present and probably consumed many of the weakened sheefish. he-lake was checked on July 1, but no fish were observed, and seining yielded no fish. Water temperature was 57OF. A gill net set on October 10 between the island and the east shore in water 2 to 5 ft deep took 13 sheefish. All were about the same size and nine were released. The four sampled were very fat and in excellent condition. Fish were feeding mainly on Gammarus Fish sampled ranged from 185-196 mm (;=192 mm). Their scales averaged 27 circuli on October 10.

Four Mile Lake:

A 5 1/2 in bar mesh gill net set in Four Mile Lake in late July 1979 took no sheefish, but two were captured in 12 man hours of hook and line fishing .

Both fish were in very poor condition. They were Age IX (1969 plant). The 613 mm male weighed 4 3/4 lbs and the 600 mm female weighed 4 1/2 pounds. The female had some retained eggs, but the ovaries were very soft. It is obvious that the rainbow trout in Four Mile Lake have competed with the sheefish for food to the point where the sheefish are losing weight. Those caught in 1979 were so thin that they could easily swim through the gill net meshes. Condition (K) factors of 1979 fish averaged 0.56 while K factors of fish caught in 1978 (n=5) averaged 0.63.

A significant biological event has occurred in Four Mile Lake; In August 1979 an angler provided us with a 368 mm sheefish for examination. The fish was 3 years of age, indicating it had been spawned and hatched in Four Mile Lake. All of our previous experience and all literature references indicate that sheefish have very stringent spawning requirements and would spawn only in water of moderate depth, swift current to keep the bottom clear of algae, and presence of differentially sized gravel. There have been no records of sheefish spawning in lakes. Moreover, Four Mile Lake has a mud and silt bottom. The fish had hatched in the spring of 1976 (adults had spawned in October 1975) and had put on 53% of its total length (195 mm) by Age I and 80% of its length (294 mrn) by Age 11, which corre- sponds to early June of 1978. This is the date of stocking 25,000 rainbow trout fingerlings. Thereafter growth of this sheefish slowed considerably in face of heavy competition from rainbow trout.

Because of marginal spawning habitat, it is probable that few of the eggs spawned in 1975 hatched. Examination of ovaries of fish captured in Four Mile Lake indicated that more females would be spawning in 1976, 1977 and 1978 than in 1975. Potential spawners were first found in 1974. Further sampling will be conducted to determine if spawning was successful in years other than 1975. Walden Pond:

Six sheefish were caught during two net nights of fishing in late July 1979 in Walden Pond. Water temperature was- 5g°F. Five of the fish were sampled, and ranged from 415 to 515 mm (x=489 mm). The fish were stocked in March 1978 (n=67) at a length range of 260-370 mm and in March 1979 (n=19) at a length range of 380 to 430 mm. Only two fish were captured in July 1978 during one net night of fishing. Weight of fish stocked in 1978 was 280-410 g; fish stocked in 1979 were 568 to 854 g. Fish captured in 1978 in Walden Pond weighed 525 and 700 g, while fish captured in 1979 weighed 790-1,590 g (;=I ,250 g) . Growth has been excellent and weight has almost. doubled in one year. The five fish captured in Walden Pond on July 30, 1979, were larger than five sheefish of the same age captured in Eielson Cooling Pond on August 8, 1979 (489 mm for Walden Pond vs. 447 mm in Eielson Pond). Walden Pond fish were much heavier than fish remaining in Eielson Cooling Pond, averaging 1,250 g vs. 1,045 g for Eielson fish.

Walden Pond fish were feeding only on insects, thus their growth rate will probably decrease as it has in other lakes where insects are the only food source. One of two males captured in 1975 was mature.

An attempt to determine year of stocking (1978 or 1979) of fish captured in Walden Pond in 1979 was unsuccessful. Scales of the five Walden Pond fish had 47-54 circuli to Age I and 17-29 to Age 11. This was so similar to circuli counts of fish remaining in Eielson Cooling Pond (16-24 circuli from annulus I to annulus 11) that year of stocking could not be determined .

The pattern of circuli formation of fish in Walden Pond is similar to that of Eielson Pond. There is a slowing of growth before annulus formation for both groups. This is surprising since the Eielson Pond remains open year- round and water temperature seldom drops below 50°F. Except for a 445 mrn fish from Walden Pond which showed little plus growth on. its scales, the pattern of circuli growth for the two groups is similar. The use of circuli counts during the first year of life for "marking" fish still may have application. Table 2 indicates average number of circuli to Age I for sheefish from various waters of Alaska.

Eielson Cooling Pond:

In spite of visual observations, gill-netting, fyke-netting, and electro- shocking little evidence of the 10,000 fry stocked in March, 1979 was found. One 160 rnm fingerling was captured on August 16, by gill net. None were captured in October 1979, or in March of 1980. No fish of the February 1978 plant were captured during 1979 and 1980 sampling.

In March 1979, 26 sheefish were captured in Eielson Cooling Pond during 20 net nights of fishing. Water temperature was 47OF. Nineteen of the fish were placed in Walden Pond. Gill-netting in the cooling pond during August (four net nights) took five sheefish and a gill net set in October 1979 took two sheefish. All of these fish were Age 11 (1977 plant). Growth has Table 2. Average number of scale circuli to Age I for sheefish from various waters of Alaska.

Number of Circuli to First Annulus Locat ion Number Mean Range

Walden Pond 5 50 47-52

Eielson Pond 6 51 46-53

Island Lake 5 27" 26-29

Four Mile Lake 6 30 27-32

Innoko River 5 22.4 20-25

* October 10 only. slowed considerably from the first year of life, and little plus growth was evident on scales of the two fish taken in October. Fish were still feeding on insects, mainly diptera larvae, but adult beetles and bugs were also eaten. Fish captured in March 1978 (n=8) ranged in length from 380 to 420 mm (;=413) and in weight from 568 to 854 g (x=685). August fish were 418 to 460 mm (&447) and 1,050 g. October fish were 455 and 485 mm and 1,020 and 1,250 g. Of the 14 fish sampled during 1979 in Eielson Cooling Pond, five of the six males, but none of the eight females were judged to be potential spawners. The testes of a male taken in October had turned white, but milt could not be pressed out.

Gray1 ing Lake :

Five sheefish were captured during one net night of fishing in August in this small 10 a lake on Eielson Air Force Base. Grayling Lake is also known to c)ntain a natural population of humpback whitefish and pike. Grayling fly were stocked in June of 1975 (35,000) and June of 1978 (12,000). tirayling Lake has no outlet and the sheefish, whitefish and pike were probab:y carried into the lake by spring floodwater in 1973 and 1974.

This pond will be studied under the sheefish lake and river adaptability study as it will provide an excellent opportunity to study sheefish growth in a lake containing forage fish.

Three of the sheefish, 380-435 mm fork length (k403) and 509-908 g (;=625) were Age V and two 420-435 mm and 708-764 g were Age VI. All fish were immature. Two of the fish were feeding on grayling, the remainder had empty stomachs. The pattern of scale growth indicates fairly rapid growth to the first annulus, then very slow growth the next 3 or 4 years, followed by a year of rapid growth. The first year's growth is similar to that of other wild sheefish populations and could be considered normal. The slow growth of the next 3 to 4 years is difficult to explain, especially since 35,000 grayling fry were stocked on June 26, 1975. Evidently the grayling competed with the sheefish for food rather than being a prey item. The rapid growth of five of the six specimens from annulus formation in 1978 to annul-us formation in 1979 indicates that sheefish changed their feeding pattern and fed on the grayling stocked in 1978. Stomach examination of sheefish captured verifies this hypothesis. I have observed wild sheefish young-of-the-year feeding on small fish, so it is surprising that sheefish in Grayling Lake waited until 1978 to feed on grayling. Another possibil- ity is that, unless sheefish have prey fish available to them from the time they reach 40-50 nun, it may be difficult for them to change their food habilcs when prey fish do become available. This occurred at Four Mile Lake. Further sampling during 1980 should determine if sheefish continue to feed on grayling.

Comparitive Growth of Sheefish in Stocked Lakes 1969-1977

During the first 10 years of the Sheefish Lake and River Adaptibility Stud.y, fish have mainly been stocked in barren lakes. Although lakes containing prey species are high on the priority list of lakes to be stocked, the inability of the hatchery to provide fingerling size fish for stocking has been the major drawback to completing this portion of the study. The only exceptions have been Engineer Hill Lake, where 44 yearling sheefish averaging 140 mm were stocked in July of 1970, and Lost Lake, where 44,000 fry were planted in February 1973 in the presence of a small, but expanding, lake chub population. In 1974, 200,000 coho salmon were stocked in Lost Lake, resulting in competition rather than predation. The 1969 stocking of 90,000 sheefish fry in Four Mile Lake is considered a supplemental stocking, as the 4,000 fry stocked in 1968 apparently did not prey on them.

Growth of sheefish stocked in barren lakes and ponds is quite rapid the first years of life, then slows as conversion of food to growth from a diet of crustaceans and insects becomes more difficult (Table 3). After four years of rapid growth, the Four Mile Lake fish exhibit slower growth, while the wild river population from Minto Flats overtakes the lake fish at Age IV to V. The fish placed in the Eielson Cooling Pond had the fastest growth during the first years of life of any fish stocked. When some of these fish were placed in Walden Pond they grew even faster than their siblings remaining at Eielson. The Engineer Hill Lake fish were stocked at Age I (fork length = 140 mm) on top of a population of chubs. The amount of growth from Age I to I1 (163 mm), and especially from Age I1 to I11 (222 mm), is faster than that of sheefish stocked in barren lakes, and indicates that the sheefish had learned to prey on chubs. The Lost Lake situation is interesting because there were few chubs in the lake when sheefish were stocked; but a heavy stocking of coho salmon caused extreme competition and very slow growth for most sheefish after Age I. However, at least one sheefish must have learned to eat chubs and coho salmon, as it was 738 mm fork length at Age V and weighed 6,500 g, (this fish was not included in table 3) compared to 239 mm and 122 g for the other three Age V fish.

Thus it appears that sheefish need to shift to a diet of fish after at least 3-4 years of age in order to continue rapid growth. .The ideal situation would be to stock fingerling size sheefish (Age 0) in July or August at a time when young-of-the-year chubs and suckers would be available for food.

R-11-B Movements, Abundance, Population Dynamics, and Spawning Ecology of Sheefish and Whitefish in Interior and Arctic Alaska

OBJECTIVES

1. To determine spring run timing and maturity status of sheefish in the lower Tanana River.

2. To compare population structure of Holitna River sheefish (1967-1971 vs. 1978-1980). Table 3, Growth of sheefish in waters stocked during sheefish lake and river adaptibilitp study. Length of most fish was taken in July, Age 0 fish captured in October of year stocked. Fork length in mm.

Date Age at Capture Location Stocked 0 I I1 111 IV v VI VII VIII IX X XI

Four Mile Lake 1968 276 345 420 466 512 580 621 647 606

Engineer Hill Lake 1970 140 303 525

Lost Lake 1973 160 239

Eielson Cooling Pond 1977 288 320 447

Island Lake 1979 192

Grayling Lake 1973 403 428

Minto Flats* 170 285 377 466 534 603 658 704 753 828

* Minto Flats data included for comparison; fish were indigenous, not stocked. 3. To collect life history and angler use information of sheefish from other areas of Alaska in conjunction with other studies.

4. To collect data on sheefish utilization from various areas of Alaska.

5. To report on life history information on least cisco that has been collected since 1970.

FINDINGS

Test Netting Results - Lower Yukon River Tributaries

During baseline surveys on streams of the lower Yukon River in mid-June 1979, sheef ish were captured only in the Anvik, Khotol, and Innoko Rivers (Table 4). The Anvik River sheefish was caught in a slough one-half mi upriver, the Khotol River fish were all caught at the mouth, and Innoko River fish were caught throughout the 100 miles surveyed from the mouth to Holikachuk Slough. During the Innoko survey from June 23 to 26, sheefish were captured only in the main river, while adult humpback and broad whitefish and least cisco were captured only in lakes and sloughs of the Innoko. According to local residents, the upstream migration of whitefish occurs immediately after breakup and is of short duration. The distribu- tion of sheefish along the lower river suggests a slow upstream migration to feeding and spawning grounds. The situation is probably similar to other Alaskan sheefish streams in that most of the immature and non- spawning fish spend the summer feeding in the lower river, while spawning fish continue the migration to spawning grounds. Innoko River sheefish ranged from 570 to 915 mm (x=710) and 2.1 to 9.1 kg and in age from V to XI1 (Table 5). They were feeding heavily on a downstream migration of whitefish and also on fingerling northern pike. Only four of the 22 Innoko River sheefish sampled were females, and three of the four were mature; 17 of the 18 males were mature. All fish Age VII and over were mature. Growth of Innoko River sheefish is faster than that of any other natural population in Alaska (Alt 1973), including the rapidly growing sheefish from the anadromous lower Yukon River population, and Nowitna River sheefish (Alt 1974). Sheefish were observed jumping in the lower Bonasila River, but none were captured. Sheefish were present in the lower Melozitna River near Ruby (middle Yukon River) on June 16 and two fish were observed; on June 27 two sheefish were captured on hook and line in the lower Melozitna, a 100 cm female prespawner and a 72 cm male prespawner.

Lower Tanana River Sheefish Run Timine

Fifteen sheefish were caught during 15 net nights of fishing in the Tolovana River and tributaries of the lower Tanana River in mid-May (Table 6). Fish ranged in length from 590 to 830 mm. All female sheefish were Table 4. Sheefish catch statistics--lower Yukon River tributaries June 19- 27, 1979.

-- Locat ion Net Nights Sheefish Captured Size Range (nun)

Nulato River 3 0

Khotol River 3 4 613-713

Anvik River 12 1 781

Bonasia River

Innoko River*

* Thirty sheefish were also captured by hook and line. Table 5. Age-length relationships for sheefish from the lower Yukon River. Fork length in millimeters at capture in June, 1979.

Age At Capture v vI VII VIII IX X XI XI1 - Innoko River x 572 626 7 08 718 762 844 915 882 n 1 1 3 9 7 1 1 1 Range 572 62 6 680-723 600-801 7 14-826 844 915 882

Khotol River

Range - Anvik River X n Range

Yukon River (Ruby) Range Table 6. Lower Tanana River test netting May 14-19, 1979.

Net Species Area Nights SF HWF BWF RWF LC1 NP LNS BB

Swanneck-Tolovana

Tolovana River 1 3

Tatalina-Chatanika 1

Baker Creek 1 2 1 1

Zitziana River 4 6 1 2 14 9 3

Tolovana mouth 1 2 2 1 1 1 either immature or non-consecutive spawners. Two males possibly would spawn in the fall. The three nets at the junction of the Tolovana River and Swaneck Slough took all five sheefish during the second night of fishing. It is not known if this indicates that the run was just beginning to enter the Tolovana River from wintering grounds. In 1968 sheefish were captured in the vicinity of New Minto Village (60 mi further up the Tolovana) on May 8, before breakup. Because of the small number of sheefish captured, an early upstream migration in the Tanana River was not conclusively proven. Results of 1978 test netting (Alt 1979) and the present study are still not sufficient to determine population status of these fish. My tenative conclusion is that the home range of sheefish of the Minto Flats population includes the area of the lower Tanana River. Since most fish captured appear to be residents feeding at mouths of tribu- tary rivers, absolute dates of run timing into the Minto Flats cannot be ascertained.

Search for Rearing Sheefish--Selawik Area

In 1979 test netting was conducted in 10 areas of Selawik Lake and vicinity (Figure 1). Nineteen sheef ish were captured, ranging in size from 500 to 806 mm, and included both immature and mature specimens (Table 7). The largest catch per net night (4) was made in a net set in Selawik Lake one-third-mile out from the mouth of the Tuklomarak River. Nets were set in close proximity to the mouth of the Tuklomarak and Selawik rivers to capture young-of -the-year and Age I and I1 sheefish, but no sheefish younger than Age IV were captured. No small sheefish were captured by seining. Small rearing sheefish are evidently not present in smaller lakes such as Roy Smith and Tuklomarak lakes. The area of Inland Lake and the Selawik River and associated lakes and sloughs close to Selawik Lake have not been surveyed, and small sheefish may be present in these areas since spawning areas are located up the Selawik River. During surveys of 1978 and 1979 in the Kotzebue and lower Kobuk-Selawik areas no sheefish younger than Age I1 have been captured. Of those sheefish captured, the smallest fish have been captured in estuarine areas near Kotzebue Sound (Alt 1979). The largest catches of sheefish per net night have also been made in these estuarine areas. The conclusions reached thus far in the search for rearing grounds of Kobuk and Selawik River sheefish are: 1) sheefish do not rear in the small lakes of the lower Kobuk and Selawik rivers, probably because of the presence of large numbers of pike; 2) rearing immature fish of Ages IV-X are found in Hotham Inlet, Selawik Lake and the lower Kobuk, lower Selawik and Tuklomarak rivers; 3) the estuarine environment of the Kotzebue Sound area is very important for rearing sheefish, especially those of Ages I1 to VIII.

Utilization Studies

Kobuk River:

In 1979 the Kobuk River became ice-free on May 16 and the Selawik River on May 19--both 1 to 2 weeks earlier than normal. Subsistence fishermen set Figure 1. Selawik Lake area netting locations. Table 7. Test netting results Selawik area May 29-June 6, i979. Letters in parentheses refer to locations in Figure 1.

Net Species Nights SF LC I BWF HWF NP LNS BB

Attiunuk Channel (A) 2 1 (Hotham Inlet)

Selawik Lake (B) 4 4 (Mukuksok Channel)

Tuklomarak River* (C)

Selawik Lake (D) (Tuklomarak R. mouth)

Selawik Lake (E)

Selawik Lake (F) (Shoniktck Say)

Selawik River (G) 1

Roy Smith Lake (H) 1 12 8

Tuklomarak Lake (I) 1 4 12 6

Middle Lake (J) 1 4 4 8 6 1

* Also 3 smelt. nets in the vicinity of Noorvik shortly after breakup. On May 30 there were 19 nets close to Noorvik and on June 2 there were 20 nets. The first subsistence net at Kiana was set on June 2. Fish camps were established in the lower Kobuk River after breakup and five camps were counted on May 30. Camps were always established at the junction of a slough leading to a lake, as whitefish were migrating into these sloughs for summer feeding. Nets were also set in the Kobuk River to intercept upstream migrating sheefish. The Barr Family camp was visited on May 31. They have the best sheefish location on the lower Kobuk River (Mukuksuk Channel) and captured the first sheefish on May 21. May 24 was the peak of the upstream migration and on May 31 they captured only 14 sheefish. They said that another peak would occur when the smelt passed through. Their camp had about 250 sheefish, 50 pike, and 150 whitefish hanging to dry.

The first sport fishing was reported at the mouth of the Kobuk River on May 22 when five anglers from Kiana caught three sheefish. From May 30 to June 2 we observed 19 fishermen capture approximately 75 sheefish in the lower Kobuk River. Additionally three of us caught 58 sheefish on hook and line during this period. Peak fishing occurred during the 6 hour period on June 1 when a huge upstream spawning migration of smelt entered the Kobuk River. Fish captured were 3-41 pounds. With the exception of two boats (six people) from Kotzebue, all fishermen were local residents. There is light to moderate sport fishing pressure as well as moderate subsistence fishing pressure on sheefish stocks as they migrate up to the spawning grounds. Over 90% of the fishing pressure is from local residents. A guide at Kiana took out fewer than 10 parties in 1979, another guide from the Alatna River took out six parties. Non-local recreational fishermen from other parts of Alaska and a few non-residents fly their own planes to the upper Kobuk River to fish for sheefish, or land at villages along the river and rent a boat. during the summers of 1978 and 1979 we received complaints of non- local "sportsmen" killing and wasting large numbers of sheefish in the upper river.

In 1979 there were reported to be 71 airplanes from Fairbanks, later reported as seven airplanes,and 71 fishermen setting up a guiding operation 23 mi above Kobuk. A local resident was taking the fishermen out to various fishing locations. Our best estimate of the situation was that about 20 fishermen, with seven airplanes had taken approximately 200 fish and kept about 600 pounds of fillets. The upper river from Selby River down to 20 mi above Kobuk was patrolled by riverboat and airplane from August 22 to 27 and we saw only one airplane in the vicinity, which was engaged in hunting. Bad weather during part of that period may have hampered fishermen. Travel is a problem and it is normally a 3-hour one- way aircraft flight from Fairbanks to the upper Kobuk River, thus it is not likely that Fairbanks-based pressure will be a major factor in sheefish harvest. Five subsistence camps were set up in the upper Kobuk River. Mainly chum salmon but also 200 sheefish and some whitefish were taken. Subsistence fishing at Ambler and Kobuk had been poor and only 150 sheefish were observed drying in late August. In late September people all along the Kobuk River were busy subsistence netting and seining for sheefish, chum salmon, humpback and broad whitefish, as well as least cisco. Selawik Area:

Breakup at the Selawik River began on May 16. On June 2 Selawik residents were capturing sheefish on hook and line at the mouth of Tuklomarak River. From June 2 to June 6, 70 fishermen were counted; all were local residents. Fishermen had caught 5-10 fish per angler trip at an average size of about 5 lbs per fish. Most Selawik anglers began fishing late in the afternoon, then fished throughout the evening--thus an angler day consists of parts of 2 days. Most fish were caught in Selawik Lake off the mouth of the Tuklomarak River, in the Tuklomarak River itself, in a slough off Tuklomarak River at the Inland Lake Channel in the Selawik River, and at the mouth of Selawik River.

In 10 man days of fishing we caught 86 fish, which was considerably higher than the catch rate of local residents.

Selawik residents mentioned that they do considerably less ice fishing for sheefish than in previous years as they now have fewer dogs. They generally go to the lake for day trips and take the fish back to Selawik and freeze them. Traditional subsistence netting for sheefish, whitefish and pike still occurs after breakup in the lake, river and slough environments in the Selawik area. In early June 1979 only one camp was set up, but fishermen traveled from their homes to check their nets. On June 6 about 300 sheefish, plus a few pike and whitefish, sere hanging to dry. Resi- dents mentioned that their freezers were full of fish at that time.

Holitna River:

From July 11 to 19, 26 sport fishermen were recorded at the Holitna River and a minimum of 14 sheefish were killed. Nearly all the fishermen were guided, with the remainder being local residents. Numbers of non-local fishermen flying their own planes into Sleetmute to fish the Holitna continue to remain low due to unavailability of gas, boats and services.

Fishing patterns for guided fishermen in the Holitna River continue to change. Formerly they were interested in sheefish only, but now chinook salmon and pike are actively sought by sport fishermen. Sheefish continue to be the most sought-after species in late June and early July until the chinook salmon reach holding areas further up the Holitna River. The run timing of sheefish into traditional feeding areas of the lower Holitna River continues to be earlier than during our research in 1967-1971. At that time peak sport fishing was from July 4 to 15; during the past few years it has been June 20 to July 4. Guides reported that many small feeder sheefish were present in late June, but during my stay they had disappeared. Size of sport caught fish ranged from 4 to 27.5 pounds. The latter is the largest sport-caught sheefish ever registered from the Holitna River. Local residents mentioned that they had done more recreational fishing earlier in the season, but were now busy on salmon subsistence activity. Yukon River Tributaries:

Yukon River tributaries, especially the Nowitna and Melozitna rivers, but also clear streams and sloughs in the Ruby and Galena areas, provide sport fishing opportunities for local residents. Although sheefish were present in the lower Melozitna River by June 17, none were captured on hook and line until June 26, and Ruby and Galena residents generally wait until July 1 to begin sport fishing. No sport fishing for sheefish was observed at the Nowitna, Khotol, Anvik, Bonasila, or Innoko Rivers during research from June 16 to 27. Anvik residents report that they sport fished in late May and early June in the lower Anvik. Residents of Holy Cross and Shageluk report that they do very little sport fishing for sheefish on the Innoko River. Presently there are no guided operations for sheefish on the Innoko River, although several guides have expressed interest. I feel that the population of sheefish in the Innoko River is of sufficient magnitude to promote more recreational fishing. Travel is a problem, however, as the river is a considerable distance from population centers.

Life-- History of the Least Cisco in Alaska

Background:

The least cisco has limited subsistence, commercial, and sport value in Alaska but is important in the food chain of predaceous sheefish, northern pike, and burbot.

Other than studies on the Arctic Ocean drainages of the North Slope of Alaska, eg. Cohen (1954), Wohlschlag (1954), Alt and Kogl (1973) published biological data on least cisco, especially in interior Alaska, are rare.

This paper summarizes biological data on least cisco collected by the Alaska Department of Fish and Game from 1968 to 1979 during research on inconnu, and during routine lake and stream surveys in interior and northern Alaska. It is hoped that this basic information will serve as a guide to future researchers.

Taxonomic Notes:

McPhail and Lindsey (1970) feel that the least cisco in Alaska constitutes a single species, but that two forms might exist. Separation has been based on size (larger or smaller than 220 mm), behavior (migratory or non-migratory), and presence or absence of spotting on the back and dorsal fin.

Gill raker counts have been used to separate other species of whitefish, but not the least cisco, although McPhail and Lindsey mention that the large migratory form has 48 to 53 gill rakers, with a mean near 50.

Gill raker counts of the least cisco over its worldwide range are reported as 34 to 52 for Siberian fish, (Berg 1948) and 42 to 53 for Alaskan fish (McPhail and Lindsey 1970). During the present study, gill raker counts were taken on fish from seven populations (Table 8) (Figure 2). Mean counts ranged from 39.1 to 47.3, with St. Lawrence Island fish (migratory) having the lowest counts. There is little indication that Alaska non-migratory least cisco have fewer gill rakers than migratory forms.

Presence or absence of spotting on least cisco captured in 1978 and 1979 was noted, and no meaningful pattern could be discerned between sexes, size groupings, and life history types. Presence of a varying degree of spotting was observed on some of the lake dwelling, river resident, and anadromous fish. Rae Baxter, Alaska Department of Fish and Game, Bethel, (personal communication), noted the same spotting inconsistencies in least cisco of the different life history forms in lakes and rivers of the lower Kuskokwim River and Yukon River Delta.

Age and Growth:

Samples of fish from six non-migratory lake groups and 11 migratory groups were aged and yielded fish from Ages I to XI1 (Table 9).

There is considerable difference in growth, maximum size, and maximum age between the various groups of least cisco aged. Lake dwelling non- migratory forms are generally slower growing than migratory forms, except that Elusive Lake fish grow rapidly. Least cisco in three of the five landlocked lakes grew larger than 330 mm. Growth and maximum size are probably more related to basic water productivity than geographic location or genetic factors. Fish from Inyorurak and Akuliak Lakes have somewhat similar growth, but maximum age of Inyorurak fish was Age IV while Akuliak Lake cisco reached Age VIII and a maximum size of 360 mm. Further sampling may be necessary to insure that all age groups are represented.

Samples were collected early in the season (late May and June) in most areas. In others (Kobuk, Ambler and Chatanika Rivers) fish were collected in late fall, giving these a larger size at capture than fish taken in spring immediately after annulus formation.

Of the river fish sampled, anadromous populations (Prudhoe Bay, Imuruk Basin, Nome River, and Kobuk River) grew slower than fluvial-migratory populations (Chatanika, Koyukuk, and Aniak Rivers), with fish from the Beaufort Sea drainage (Prudhoe Bay) being the slowest growing. These slower growing fish had the longest life span, at least from the Prudhoe Bay and Imuruk Basin areas. Interior Alaska fluvial populations of least cisco, including Aniak River fish, are fastest growing and reach a mean length of 200 mm by Age IV or V.

The dwarf sized Lake Minchumina least cisco are the slowest-growing of all populations studied and have the shortest life span. Humpback whitefish from Lake Minchumina are also the slowest-growing humpback whitefish in Alaska (Alt 1979). Since Lake Minchumina has a large outlet to the Kantishna River, it is possible that a fluvial migratory form could enter Lake Minchumina and spawn in the fall. Commercial and subsistence fisher- Table 8. Gill raker counts of Alaskan least cisco.

Water n Mean Range

Chatanika River 38 43.0 36-52

Ambler River 16 46.6 44-50

Co lville River 10 43.9 41-47

Imuruk Basin 10 47.3 45-50

Upper Yukon River 5 44.6 43-45

St. Lawrence Island 10 39.1 37-44

Elusive Iake 13 43.5 41-47 Figure 2. Lease cisco sampling areas. Table 9. Mean fork length (mm) at capture of least cisco from various Alaskan waters 1968-1979. Chatanika River data back-calculated. Numbers in parentheses refer to locations in Fig. 2.

Age At Capture Water n 1 2 3 4 5 6 7 8 9 10 11 12

Harding Lake (7) 69 165 181 199 228 228 232 276 339

Lake Minchumina (5) 22 108 112 129 135

Elusive Lake (16) 28 166 255 286 362 384

Akuliak Lake (14) 14 150 240 287 310 360

Inyorurak Lake (15) 16 145 197 210

Wellesley Lake (8) 14 218 292 306 310

Aniak River (1) 73 108 221 262 284 293 309 325 372 407

Chatanika River (6) 164 120 208 261 304 337 364 387 410

Lower Tanana River (4) 56 118 230 243 288 305 322 355

Middle Yukon River (3) 65 142 235 248 279 324 329

Lower Koyukuk (2) 21 130 235 264 307 323 328 335 362

Imuruk Basin (10) 17 217 225 239 262 265 258 240

Nome River (9) 44 219 259 265 287 285

Kobuk River (12) 149 222 233 241 253 260

Ambler River (13) 62 263 269 285 287 316

Prudhoe Bay (17) 27 1 55 106 130 162 190 218 250 273 297 321 340 359 men on the Lake have not reported such a run, but mesh size of their nets is too larg. to catch least cisco. Lake populations of cisco from northern Alaska were faster-growing than fish from Harding Lake (Tanana system), but grew about as fast as fish from Wellesly Lake, another Tanana River system lake.

Russian researchers report the same variability in growth and longevity of least cisco from different habitats and geographic locations as is found in Alaska (Berg 1948; Nikolsky 1954). Siberian least cisco from the larger rivers, such as the Lena, Yana, Yenisei, Khatanga, and Ob, grow slightly slower than cisco from interior Alaska, but approximately as fast as Nome and Kobuk River cisco.

Mann (1974) found that esturaine populations of least cisco in Arctic Canada grew more rapidly, at least during the first 5 years of life, than lake resident fish. In Alaska considerable variation in growth patterns was found between lake and stream fish and between southern or northern and coastal or interior populations.

Rae Baxter (unpublished ms.) found migratory least cisco from the lower Kuskokwim River ranging from 90 to 419 mm in length and from 11 to 703 g in weight (n=383), and landlocked cisco from Kgun Lake (lower Kuskokwim drainage) from 230 to 469 mm fork length and 141 to 1,932 g in weight (~147). Mean K factor (condition) for Kuskokwim River fish was 1.08, while the Kgun Lake K factor was 1.47.

Spawning:

Least cisco spawning activity has been observed in the Chatanika River in interior Alaska and in the Kobuk River in northwest Alaska. The fluvial migratory population of least cisco that spend the spring and summer feeding in the extensive lake, river, and slough system of the Minto Flats migrate 100-120 mi up the Chatanika River in July, August, and September to spawn.

Least cisco in this system reach the largest size in Alaska, with spawning males averaging 310 mm fork length with a range of 230 to 450 mm. Weight range of males was 241 to 805 g (x=406 g) and for females 427-1,227 g (~~685g). The spawning population ranges in age from I1 to VII with Ages IV, V, and VI most common.

Egg diameter at spawning ranged from 1.45 to 1.65 mm (n=43) and older fish generally had larger eggs. Ovary weight averaged 21.4% of body weight. Fecundity ranged from 9,800 eggs for a 291 mm fish to 93,500 eggs for a 413 rnm fish (n=43). Table 10 gives average fecundity for each 10 mm size group in the spawning population sampled in 1972.

Total 1972 visual count of least cisco in 19 spawning areas located from 10 mi below the Elliott Highway Bridge to 7.5 mi above the bridge near Fairbanks, was 16,500 fish, with a range from 50 to 1,500 cisco per spawning area. Table 10. Mean fecundity for each 10 mm size group in the Chatanika River

spawning population, ' 1972.

Fork Length (mm) x Fecundity Range

291-300 9,800 9,800

301-31 0 27,825 23,750-31,900

3 11-3 !O 32,363 26,125-37,840

321-330 37,519 26,400-52,500

331-340 41,861 35,880-46,000

341-350 50,584 39,520-75,000

351-360 69,333 58,000-87,500

361-370 68,670 53,000-80,000

371-380 70,702 62,160-87,500

381-390 60,833 60,000-61,750

391-400 76,500 68,250-82,500

401-410 86,645 80,640-92,650

411-420 93,500 93,500 The spawning period was from September 19 to October 3, in 1972. Spawning observations were made on September 22 through September 30. Water temperature ranged from 32O to 42OF. Most spawning occurred at night, with peak spawning activity around 1900 hours. Most spawning occurred in water 8 ft deep over a gravel bottom in moderate current, although some spawning was observed over a sand and silt bottom where current was slower and water depth from 3 to 6 feet.

The most common spawning behavior was a spawning jump perpendicular to the movement of the current. Grouping and ascent began about 1 ft above the gravel bottom, then the fish broke water with their heads, went into a backward or side roll, separated and returned to the bottom. Eggs and milt were expelled while fish were rolling. Females were slightly ahead of the males. The spawning jumps included a male and female or combinations of up to two females and three males. On September 28 from 2115 to 2230 hours, 168 spawning jumps were observed on the Chatanika River.

Another spawning pattern was occasionally observed. This was a side-by- side movement for 5 to 12 ft against the current close to the bottom, similar to movements observed on the upper Kobuk River.

Post-spawning migrations includes a rapid movement downstream until feeding areas are reached.

Least cisco of the anadromous (small sized), Kobuk River population were observed spawning by the author September 29, 1965, 35 km above the village of Kobuk. Observations were made from 1600 to 1800 hours during observations of shzefish spawning. Least cisco were spawning in water 1 to 3 ft deep, 3 to 10 ft out from shore in a slow to moderate current ( 2.5-4 ft/sec). Sheefish were spawning at the same time, but from 15 to 40 ft from shore and over deeper water (Alt 1969). Water temperature was 36OF. Bottom was composed of gravel with diameters ranging from 0.25 to 3 in.. Spawning least cisco were facing upstream, then would turn on their sides and arch their bodies, presumably broadcasting eggs and milt while doing so. This activity took place midway in the water column.

The anadromous population evidently spawns along a large area of the Kobuk River, as large numbers of ripe fish were taken on September 30, 1979, 21 mi below Ambler. Water temperature was 38OF. On October 1, 1979, the larger sized, deeper bodied, fluvial migratory least cisco were captured 2.9 mi up the Ambler River. Some had loose eggs, but spawning was a number of days away. Ambler residents indicated that both anadromous and fluvial migratory forms ascend the Ambler River to spawn, and our sample may have included some of the latter.

Least cisco are present in the main Yukon River throughout the summer, but a definite upstream spawning migration occurs in September, as two to three individuals were taken daily in a fish wheel located near Rampart. Eggs were held tightly in the ovaries in l.ate September and spawning grounds have not been located. Food Habits:

Fragmentary food habits data indicate that least cisco are indiscriminate and feed on crustaceans and insects. Brackish water least cisco generally feed more on copepods and amphipods than insects, while river-dwelling fish feed mainly on diptera larvae, but to a lesser extent on adults of the orders Coleoptera, Hemiptera, and Homoptera, and also some snails, clams, and freshwater shrimp (Gammarus ) Lake dwelling cisco feed on crustaceans, insects, plankton and occasionally snails. During the study least cisco predation on chum salmon was observed in the lower Aniak River on May 12, 1975. A 380 mm least cisco contained 57 chum salmon fry and a 350 mm cisco contained 31 fry. Since little sampling is done on interior Alaskan rivers immediately after ice-out when chum salmon fry are leaving the rivers, this significant predation by least cisco and other whitefish species common to lower reaches of Alaskan rivers could easily be over- looked.

Like most other species of Alaskan whitefish, least cisco cease feeding prior to spawning.

Parasites:

Cursory examinations of cisco collected during the years of this study indicated varying degrees of parasite infections. The highest incidence of parasites was found in the anadromous Kobuk River population, where pleurocercoid cysts of Dyphyllobothrium * were abundant on the stomach wall and the flesh contained numerous cysts of Trianophorus sp.

Lake dwelling cisco and cisco inhabiting rivers in interior Alaska and the Colville River and Prudhoe Bay, all had low incidence of parasites.

All waters surveyed during this study except for the Colville River and Prudhoe Bay contained populations of northern pike, the definitive host for Trianophorus SJL-

Utilization:

The least cisco, because of its small size and generally poorer quality, is not as important a subsistence food item in rural Alaska as are the humpback and broad whitefish, but is locally important. Residents of the lower Kuskokwim and Yukon Rivers and associated delta areas capture cisco for human consumption and dog food; and 10,000 to 40,000 fish are taken annually by residents along the Kobuk River in northwest Alaska.

A commercial fishery for least cisco at the delta of the Colville River has been taking between 20,000 and 40,000 fish per year, averaging about 400 g in weight.

A few least cisco are taken by sport fishermen incidently while fishing for other species, and a fall spear sport fishery on the Chatanika River near Fairbanks takes 500 to 2,000 least cisco annually. The Coregonus- sardinella species complex is one of the most valuable commercial species in the lower reaches of Siberian rivers and in the past years up to 4 million kg have been taken annually (Nikolsky and Reshetnikov 19?0).

LITERATURE CITED

Alt, K. T. 1969. Taxonomy and ecology of the inconnu, Stenodus leucichthys nelma, in Alaska. Biol. Pap. Univ. Alaska No. 12. 63p.

. 1973. Age and growth of the inconnue, Stenodus leucichthys, in Alaska. Journal of the Fisheries Research Board of Canada 30:457-

. 1976, Age and growth of Alaskan broad whitefish Coregonus --nasus Trans. Am Fish Soc. 105:526-528. . 1979, Contributions to the life history of the humpback whitefish in Alaska. Trans. Am. Fish Soc. 108:156-160.

Alt, K. T. and D. R. Kogl. 1973. Notes on the whitefish of the Colville River, Alaska. Journal of the Fisheries Research Board of Canada. 30:554-556.

Berg, L. S. 1948. Freshwater fishes of the U.S.S.R. and adjacent countries. 4th Edition, Vol. 1, Academy of Science, USSR, Moscow. Translated from Russian by Israel Program for Scientific Translations, OTS 61-31218, Jerusalem, 1962. 504p.

Cohen, D. M. 1954. Age and growth studies on two species of whitefish from Point Barrow, Alaska. Stanford Ichthyological Bulletin 4(3):168- 188.

Mann, G. J. 1974. Life history types of the least cisco, Coregonus sardinella Valenciennes, in the Yukon Territory, North Slope, and Limited, Biological Report Series 18(3): 160p.

McPhail, J. D. and C. C. Lindsey. 1970. Freshwater fishes of Northwestern Canada and Alaska. Fisheries Research Board of Canada, Bulletin 173.

Nikolsky, G. 1954. Chartnaya ikhtiologiya (special Ichthyology). Gousudaralevennol Izdatel. "Sovetskaya nauka" . Moskva . 538p. Translated by Israel Program for Scientific Translations, Jerusalem, 1961.

Nikolsky, G. and Yu. S. Reshetnikov. 1970. Systematics of coregonid fishes in the USSR; intraspecies variablility and difficulties in taxonomy. In: Biology of Coregonid Fishes. Univ. Manitoba Press, Winnipeg. Wohlschlag, D. E. 1954. Growth perculiarities of the cisco Coregonus sardinella Valenciennes, in the vicinity of Point Barrow, Alaska. Stanford Ichthyological Bulletin 4(3):188-209

Prepared by: Approved by:

Kenneth T. Alt Rupert E. Andrews, Director Fishery Biologist Sport Fish Division

Mark C. Warner, Ph.D. Sport Fish Research Chief