CHAPTER II LIFE HISTORY OF THE GRAYLING DRAINAGES IN THE YUKON TERRITORY. (Thymallus arcticus) IN BEAUFORT SEA. w ~ M. de BRUYN P.

Transcription

1 CHAPTER II IFE HISTORY OF THE GRAYING (Thymallus artius) IN BEAUFORT SEA DRAINAGES IN THE YUKON TERRITORY M. de BRUYN P. MCART a: w ~ Q. C :I:

2 ERRATA- VOUME FIFTEEN TABE OP CONTENTS line 2: line 24: "ANDS" should read "AKES" "SPRING TIED" should read "SPRING FED" Chapter I p.l7, COMMENTS, line 3: p.49, Condutivity: p.l41, COMMENTS: p.l52, Sample loality: p.l54, Sample loality: "large on" should read "large one" "72" should read "2+" " ygen levels" should read "Oxygen levels" "3 1/2 m" should read "3 1/2 miles" "2 mi" should read "2 miles" Chapter II p.3, line 21: p.4, line 12: p.7, line 17: p.s, line 8: p.22, line 12: p.22, line 14: p.23, line 13: p.27, line 9: p.27, line II: p.28, line 4: p.3, line 2: p.38: Delete referenes: "Aquati Environments imited, Winter Data Report" shoud read "Chapter I of this volume" "6 F" should read "15 C" "the fish had been aged" should read "the ages of the fish had been determined" "For the purpose of aging" should read "To determine age" "ration (Table IV). the sex" should read "ratio (Table IV). The sex" "the Age" should read "the age" "feudnity" should read "feundity" "Probably" should read "Probable" "the ourane" should read ", and the ourrene" "downstream" should read "upstream" "Craig, 197 3" should read "Chapter III of this volume" "Aquati Environments imite!!! " "Craig, P.C " Add referenes: "Brown,.E Permafrost in Canada- Its influene on northern development. Univ. of Toronto Press, Toronto." "Dunan, D.B Multiple range and multiple F tests. Biometris, II: 1-42."

3 ~~- ) ---~: ~------~~ ~ ~ TABE OF CONTENTS Page 1. ~. INTRODUCTION DESCRIPTION OF THE STUDY AREA Physiography.2 Streams akes MATERIAS AND METHODS RESUTS AND DISCUSSION Distribution of Grayling in the Study Area 8.11 Firth River 9.12 Babbage River System.13 Other Mountain Streams.14 Tundra Streams.15 akes.2 Age & Growth.21 First Year Growth.22 Growth of Older Fish Comparison with Growth in Other Areas 21.3 Age at Maturity.4 Sex Ratios Egg Size, Feundity and Frequeny of Spawning,6 Spawning Period Fry Emergene 26.8 Spawning and Rearing Areas.9 Movements in Streams and Overwintering Areas i -

4 ~--'\..,..1 Food Habits.11 Parasites ITERATURE CITED PATES Following page 39 - ii- F_,

5 -~-----~---- "' ~~--~~ ~~~ / IST OF FIGURES AND TABES Follows Page Figure 1. Map of the study area showing the loation of streams and lakes. Unnamed waterbodies have been assigned a 2 number. Blak triangle indiates loation of sampling site at the head of the Firth River Delta. Figure 2. oation of spring-fed aufeis fields in the study area. 4 Table 1. Distribution of fish speies in lakes examined during fisheries investigations in Beaufort Sea drainages in the Yukon Territory, Figure 3. Fish sampling sites. 1 Figure 4. Distribution of grayling in samples. Closed irles are sites at whih adult and juvenile grayling were aptured. Open irles are those at whih young-ofth~-year were taken. 12 Figure 5. Comparison of late summer growth of fry from Stream 1 and Trail River. Temperature at the two study sites also shown. 16 Figure 6. r Comparison of age-length relationships determined from both sales and otoliths for grayling from the ower Firth River. 2 r Figure 7. Comparison of age-length relationships determined from both sales and otoliths for grayling from 2 Trout ake. iii

6 Figure 8. Comparison of growth rates of grayling from the Firth River, Trout ake 1 with those of other populations from Alaska and the Canadian Arti. Follows Page 22 ~ Figure 9. Numbers of males and females in various size lasses in samples from three loalities in the Yukon 24 Territory. Figure 1. Seasonal development in egg size for mature grayling from three loations on the Yukon North Slope. 26 Figure 11. Probable spawning areas for grayling along the Yukon North Slope. 28 r._,, r~ iv r-

7 1. INTRODUCTION The grayling (ThymaZZus aratiaus), an important sport fish, is one of the most widely distributed speies in the Western Arti (Plate 1). This report desribes the distribution and life history of the speies in Beaufort Sea drainages of the Yukon Territory. These studies are part of the efforts being expended to determine the eologial impat of the onstrution and operation of the gas pipeline proposed by Canadian Arti Gas Study imited. The studies were onduted through Northern Engineering Servies imited. They were onentrated on streams and lakes along the proposed pipeline route from the Alaska Yukon border east to the Yukon-Northwest Territories border. 2. 'DESCRIPTION OF THE STUDY AREA The study area and the names of the major drainages are shown in Figure 1..1 Physiography There are three major physiographi divisions within the study area: 1. The Arti Coastal Plain inluding the zone between the Beaufort Sea Coast and the 5 feet ontour to the south. In the study area, the plain is very narrow ranging from less than 5 miles in the viinity of Fish Creek to little more than 18 miles in the viinity -1-

8 -~----~, of the Walking River. The topography of the plain in the study area is somewhat rolling, not nearly as level as it is further west in Alaska (eg. in the viinity of Prudhoe Bay). In the more level areas drainage is poor with extensive marshy areas and shallow, often undrained lakes and ponds. 2. The Arti Foothills inlude the area between approximately the 5 feet and 25 feet ontours. The hills are typially rounded. Drainage is good and there are a number of small lakes sattered throughout the area. 3. The Arti Mountains inluding in our area, from west to east, the British, Barn and a small portion of the Rihardson Mountains. There are few lakes within the mountains but a number of important streams originate there..2 Streams In this area, the streams important to grayling an be plaed in two general ategories, Mountain Streams and Tundra Streams. Mountain streams originate in the Arti Mountains and flow northward, through the foothills and aross the oastal plain to enter the Beaufort Sea. These are generally large streams, frequently braided, both in their headwaters and near their mouths (Plate 2). Water -2- I

9 1 r--'j 1 r-1 r-1 r 'T rt1., '71 r r. r--1-1 l"1 r- ~ r-l <D ake 14 ake Firth ake ake 18 ake 15 <V ake 11 ake 1 ake 19 Bloomfield ake ake ake ake 11 ~ Trout ake Peat ake miles 5 <{ ~ (/) <{ _ <{ z ~ :::> >- zj.,..: ~ ~I. :::>'Z >-I Figure 1. Map of the study area showing the loation of streams and lakes. Unnamed water bodies have been assigned a number. Blak triangle indiates loation of sampling site at the head of the Firth River Delta.

10 levels flutuate onsiderably both during the spring and early summer when snow melt ours and later in the summ~r fall as the result of rainstorms in the mountains. and early During freshets the mountain streams beome quite turbid. There are major springs on some of the mountain streams (Fish Creek, the Firth and Babbage Rivers, oe and Canoe Creeks) and segments of these streams, in the viinity of perennial springs, flow throughout the winter (Plate 3). Suh springs an often be identified by the large areas of aufeis (layered ie) whih form downstream during the winter and may remain throughout the summer (Plate 4). Spring i.. -. areas are often important to spawning and overwintering fish (Craig, 1973). The loations of some important springs and extensive aufeis areas are indiated in Figure 2. Some mountain streams in our area are apparently without drainage from perennial springs. These inlude the Blow and Trail Rivers. Tundra streams are typially small streams whih originate in the foothills or the Arti Coastal Plain. Their primary soures "' -,: -" of flow are melt-water, runoff and lake drainage. In our area, only one perennial soure of groundwater has so far been identified on a foothills stream, this a minor seep on the Spring River (Aquati Environments imited, Winter Data Report). For this reason, tundra streams, almost without exeption, are frozen to the bottom throughout the winter. -3-

11 Summer flows in the foothills streams tend to flutuate less than those in mountain streams. Banks are generally stable supporting a thik growth of dwarf willow and birh with a heavy mat of mosses beneath (Plate 5). In many plaes, partiularly on the Arti Coastal Plain, the foothills streams are "beaded" (Brown, 1971). arge pools (the beads) have formed where massive ground ie has melted out. These pools, the bottoms of whih are overed with organi debris, alternate with straight strethes of stream (Plate 6). Where veloities are suffiient, the latter are haraterized by gravelly riffles. Water temperatures in the tundra streams are generally higher than those in mountain streams, sometimes exeeding 6 F 3 akes There are two types of lakes important to grayling in our study area. These are Tundra akes and Foothill akes (Plates 7 and 8). The former are situated on the Arti Coastal Plain. They are generally shallow and weedy: Firth Camp ake has a maximum depth of approximately 2.5 m and ake 1 a maximum depth of approximately 3. m. Many are even shallower and have insuffiient free water under winter ie, whih averages approximately 2 m, to support fish populations (Table I). Foothills akes are generally deeper than Tundra akes. Maximum reorded depths are 1 m for Trout ake, 12.5 m for ake 15 and 13.4 m for ake 17. Their bottoms are generally stony without an extensive development of the rooted aquati vegetation whih is a harateristi feature of the shallower tundra lakes. -4-

12 .,., 1. -; (\) N r n ru rt :: -n Ul - -; :: 1. I -n (\). Ill R, CD... Ill (\). Ul rt ::T (\) Ul rt. -< ru -; (\) ru - ; ] ]

13 \\\\\\\\ \\\\\\\ NI-'1-'1-'1-'NNVl 1-'\\\l-' 1-'1-'l-'1-'1-'l-'1-'1-' wwwwwwww \\\\\\\ NI-'I-'1-'1-'WW-1:- -1:--W-...\OVlOOOOW zzz~ ~ 1-hl-hl-h 1-' 1-' 1-' Cll Cll Cll ::T'::T'::T' (l (l (l Ill Ill Ill s:: s:: s:: ~~~ rtrtrt ~ FOOTHI AKES \\\\\\\\\\\ \\\\\\\\\\ 1-'NNI-'1-'1-'NVlN WNI-'-...WI-'NOO\N 1-'l-'l-'1-'1-'1-'l-'l-'1-'1-'l-' wwwwwwwwwww "'-1\-...\ VlW-1:--.:>.VlNWNONN -i:--\\\\\.:>.nowo\ zzz ~ zz~ ~ 1-hl-hl-h 1-hl-h 1-' 1-' 1-' 1-' 1-' Cll Cll Cll Cll Cll ::T'::T'::T' ::T'::T' ~ ~ (l (l (l (l (l Ill Ill Ill Ill Ill s:: s:: s:: s:: s:: OQOQ ~~~ rtrtrt ~ ~ ~::T'::T' rt rt ~ TUNDRA AKES t-' Ill rt t-' (l Ill rt 1-' ::l ake trout (SaZveZinus namayaush) Arti har (SaZveZinus azpinus) Arti grayling (ThymaZZus aratiaus) Round whitefish (Prosopium ayzindraaeum) Broad whitefish (Coregonus nasus) Humpbak whitefish (Coregonus pidsahian) east isoes (Coregonus sardinezza) Inonnu (Stenodus Zeuaiahthys mezma) Pond smelts (Hypomesus olidus) Arti flounders (iopsetta gzaaiazis) Nine spine stiklebak (Pungitius pungitius) Four horn sulpin (MyoxoaephaZus quadriaornis) ("') ~ ~ rt Cll AKE TYPE t-3 ~ 1-' (1) H Aot::l t1 1-' Ill Cll 1-' rt ::l t1 Ill 1-' OQO"' (1) s:: Cll rt 1-' 1-'- ::l ::l rto ::T'I-h (1) 1-h Kl 1-' ~~ ::l Cll 'd t-3!1> (1) (l t1 1-' t1 (1) 1-' Cll rt 1-' t1 ::l '<.. 1-' Ill 1-'!'\" \(1) -...Cil N (1) ~ 1-' ::l (1) Ao Ao s:: t1 1-' ::l OQ 1-h 1-' Cll ::T' (1) t1 1-' (1) Cll 1-' ~ (1) Cll rt 1-' OQ Ill rt 1-' ::l Cll 1-' ::l t:d (1) Ill s:: 1-h t1 rt Cl.l (1) Ill ]

14 3. MATERIAS AND METHODS Samples were obtained from most of the major lakes and streams throughout the study area to determine the general distribution of grayling. These samples were obtained by a variety of methods inluding monofilament gillnets, seine, bak-pak eletrofishing units, fyke nets and angling. In addition to this general sampling effort, more detailed life history samples were obtained from three major and two minor study sites. The three major sites were: the lower Firth River, from the head of the delta (Figure 1) to its mouth; ake 1, a ~ typial tundra lake loated about 3 miles north of the pipeline route and four miles south of Roland Bay; and Trout ake, a foothills lake situated about 4 miles south of the pipeline route west of the Babbage River. At eah loality an effort j l was made to obtain as full a size range as possible. Therefore, the samples taken do not reflet the relative abundane of the various age groups. Grayling in the lower Firth River were sampled at a gillnet r~ station at the head of the delta. This station was monitored at intervals from une 13 to September 12, The sampling gear onsisted of a gang of variable mesh monofilament gillnets (1, 1 1/2, 2, 2 1/2, 3, 3 1/2 and 4 inh streth mesh) set within a deep, bakwater pool, usually for a 12 hour period. Smaller size lasses were sampled using a fine mesh seine. Oasionally --" -5-

15 ~- _ eletrofishing and angling were used to obtain additional samples r-- downstream of the gillnet station. ake 1 and Trout ake were sampled by means of gangs of variable mesh gillnets similar to those desribed above and with a five foot diameter nylon mesh fyke net, and a fine mesh seine. Sampling was arried out on ake 1 periodially from uly 2 to August 25, and on Trout ake from uly 9 to September 12, Sine regular samples of young-of-the-year fry were not easily obtainable from any of the three major study areas, fry only were taken from two other areas, Stream 1 and the Trail River. Fry in Stream 1 near the pipeline rossing were sampled weekly between uly 3 and September 12, Samples were olleted by means of a fine mesh seine from small bak pools and along the stream edges. In the Trail River, fry samples were olleted by eletrofishing at a point about 1 miles above the pipeline rossing. The first samples were taken on August 2 along the edges of a large deep pool below a 1 foot liff. Subsequent samples were olleted weekly until September 12 in a riffle and shallow pool about 2 yards upstream from the first sampling site. Between uly 3 and August 5, 1972, samples of grayling fry were obtained from 8 streams within the study area. Water temperatures and surber samples of benthi invertebrates were taken simultaneously in riffles in the viinity of the sample sites. -6- l l r r

16 Grayling aptured were retained for detailed examination, usually performed on the day of apture. Where this was not possible the fish were frozen for later analysis. During detailed examination, fork length and total weight were reorded. Sex and state of maturity were determined by examining the gonads. Fish whih would not spawn in the next spawning period, judging by the appearane of their gonads and by general body size, and whih showed no evidene of previous spawning, E were lassified as immature. The presene of retained eggs, still attahed to the ovarian wall or free within the abdominal avity, was regarded as positive evidene of previous spawning in females. In early summer immediately after the spawning period, the distintion between small mature and immature fish was not always lear. In these ases a subjetive assessment of maturity was made on the basis of body size and external r features. In a few ases this assessment was orreted one spawning period were lassified as mature but green. the fish had been aged. Fish whih would spawn in the next,---' Fish were lassified as mature and ripe if sex produts (sperm or eggs) ould be expressed by gentle pressure on the abdomen. Females whih had reently spawned, and males that had exhausted their milt supply, were lassified as spawned-out. -" r -- Gonads were removed from most fish over 15 mm in length. Total gonad weights were determined by weighing both gonads together. -7-

17 The width of the gonads at their widest point was also reorded. Mean egg diameter was determined from the total length of ten typial eggs aligned in a trough. For feundity ounts, subsamples (approximately 1-15% of the total ovary weight) were weighted and preserved in 1% formalin for later enumeration. Total egg ounts were then determined by the simple ratio of number of eggs in the subsample to the total number of eggs. For the purpose of aging, sales were taken from an area just above the lateral line and below the posterior portion of the dorsal fin. Sales were plaed between two mirosope slides and read at a later date. MCart et al (1972) have shown that E sales may give unreliable ages for grayling. Therefore, both otoliths were also removed from eah fish. These were plaed in a small vial ontaining a drop of glyerine, and read at a later date under a binoular mirosope. An examination was made of the stomah ontents of most fish subjet to detailed analysis. First a rough estimate was made r - l r- of the perent of fullness of eah stomah. Then the ontents were listed aording to major groups (ChiPonomidae, TPihoptePa, et.) without regard to the relative abundane of eah group. 4. RESUTS AND DISCUSSION.1 Distribution of Grayling in the Study Area oalities at whih sampling attempts were made are indiated in Figure 3. Those at whih grayling were obtained are indiated -8- C r-

18 ,., ~ ~ ; in Fig~re 4. As the data indiate, grayling are widely distributed in the study area. In the following, the distribution of grayling is disussed in more detail..11 Firth River - Grayling fry were rarely taken in the upper Firth River, above the major aufeis area (Figure 2) though larger fish were abundant. Of 191 grayling aptured in the area September 25, 1972, only one (48 mm in length) was a young-of-the-year. The smallest of the other 19 fish was 275 mm. It would appear that though grayling utilize this as a summer feeding and, possibly, overwintering area, it is not an important spawning area for this speies. It is however, a major spring area utilized by a large population of spawning and overwintering Arti har. r r uvenile, young-of-the-year and adult grayling were distributed throughout the middle ourse of the Firth River from below the major aufeis area to the head of the Firth Delta but exept for a onentration of fry at Castle Rok, near the mouth of Muskeg Creek, they were not abundant. Adult and juvenile grayling were taken throughout the summer at the gillnet station at the head of the Firth Delta and fry, though diffiult to sample, were found in the braided hannels within the delta

19 Within the study area, grayling appear to make little use of tributary streams. Exept for oe Creek, a major spring-fed tributary important to anadromous Arti har, grayling were absent from mountain streams entering the Firth River sampled during the ourse of surveys. In oe Creek, a few adults were taken but no juveniles or fry were loated despite extensive eletrofishing. Oasionally during the summer, adult grayling were taken from Okpioyuak Creek, a tundra stream tributary to the lower Firth. However, the presene of fish in this stream was sporadi beause of its extremely unstable nature. Several times it dried up almost entirely, only to flood overnight with the next rainstorm. Kuparyuk Creek, another tundra stream with its mouth on the Firth River about 1/2 mile from the oean, also yielded only an oasional grayling. Reasons for this remain obsure, sine the stream flowed all summer..12 Babbage River System - The Babbage River is a major mountain stream supporting a large population of grayling. There is a major waterfall loated about 5 miles south (upstream) of the pipeline rossing, whih presents an impassable barrier to fish movements. Above the falls is a series of perennial ground water springs whih support a large population of resident Arti har. Neither juvenile nor mature grayling have yet been aptured above these falls, but three grayling fry were taken on August 28, 1972, about one mile downstream of the springs. This suggests r

20 "'T'I <.., (I> "'T'I (/) ::r (/) Ql 3 -a - : <. (/) rt (I> (/)

21 that a spawning population of grayling does exist somewhere above the falls. ~elow the falls, few mature grayling were taken in the Babbage River itself. Of the 95 grayling sampled, only 3 were mature. All others were fry and juveniles up to 172 mm in length. It seems likely that most of the adult fish and larger juveniles do not spend the summer in the Babbage River. arge numbers of adults and older juveniles were, however, present in the spring waters of Canoe (Fish Hole) Creek, a major tributary and overwintering site for anadromous Arti har. Of the 26 fish sampled from this area, the smallest had a fork length of 226 mm. The Trail and Crow Rivers, two mountain streams tributary to the lower Babbage River, ontain large numbers of young-ofthe-year grayling, plus some mature and juvenile fish, though only in their lower halves. No fish were found in the upper ourses of either of these rivers..13 Other Mountain Streams - Other mountain streams whih were found to support populations of grayling are the Blow River and its major tributary, Rapid Creek to the east and Craig Creek to the west. These streams were sampled only qualitatively to determine speies present in the viinity of the pipeline..14 Tundra Streams - Tundra streams whih were found to ontain grayling are Stream 1, Peatbog Creek, Deep Creek, Walking River, Tundra Creek and Stream 13 (Figures 1 and 4)

22 With the exeption of Stream 1, these were sampled only qualitatively in the viinity of the pipeline. Stream 1 was extensively surveyed from the air on uly 3, 1972 and only twelve adult grayling were seen in its entire length. However, fry were very abundant at that time, partiularly near the pipeline rossing, and remained so at least until September 12 when the stream was beginning to freeze over. Bryan et al (1973) aptured one grayling from the Spring River, but we found no grayling in this system. It seems doubtful that a large population utilizes this river..15 akes- Although 11 tundra lakes were sampled (Table I), only six are known to ontain fish. of grayling. (Coregonus nasus). Two of these inlude populations ake 19 ontained grayling and broad whitefish ake 1 ontains grayling, broad whitefish, pond smelt (Hypomesus olidus) and ninespine stiklebaks (Pungitius pungitius). One Arti har juvenile was also aptured in the latter lake. ~ Of the eight foothills lakes sampled, five were found to support populations of fish, and three of these ontained grayling. ake 17 has a large population of grayling whih appears to be isolated for muh of the summer as its outlet dries up. ake -, -~ ' 15 ontains grayling, least iso (Coregonus sardinella), lake trout (Salvelinus namayaush) and ninespine stiklebaks. Trout ake supports populations of grayling, least iso, humpbak -12- r

23 --~rr~r--1r:-~r:le71r-:rlr-lr-r.-1rr-1r--l kilometr11 5 I I I I I I miles 5 Fgure 4. Distribution of grayling in samples. Closed irles are sites at whih adult and juvenile grayling were aptured. Open irles are those at whih young-of-the-year were taken.

24 whitefish (Coregonus pidshian) and ninespine stiklebaks..2 Age and Growth.21 First Year Growth - Grayling fry from streams aross the Yukon North Slope exhibit onsiderable variation in their growth rates: a omparison of the mean fork lengths of fry from nine different sampling sites, olleted during a 6-day period (uly 3 to August 5, 1972) shows that fry fall into three different size groups (Table II). It appears that fry from streams situated lose to the Makenzie River Delta are signifiantly larger (p.<o.ol) than fry from more westerly streams. r= This phenomenon does not appear related either to differenes in numbers of benthos available as food, or to water temperatures sine no distint parallel pattern was found in these parameters (Table II). However, the time of break-up may be an important fator in the apparent growth rates of fry; more easterly streams were observed to break up onsiderably earlier in spring than those to the west, perhaps allowing spawning to our sooner, affording a longer growing season. Data presented in Table II suggest that fry taken from Stream 1 are somewhat atypial in their growth. Fish taken from this stream were signifiantly (p ;:;:O. 1) smaller than fry from any other area sampled, and onstitute a size group by themselves. This unusually slow growth rate is not demonstrably related to numbers of benthos or to temperature, sine neither of these

25 parameters for Stream 1 was exeptionally low in omparison to other streams. There is evidene of onsiderable variation in size between loations within a single stream. On the Trail River, one sampling site (Trail #1) was along the edges of a large deep pool about 1 miles upstream of the pipeline rossing. Table II shows that fry taken from this loale on August 2, 1972 were signifiantly (p.<:o.ol) larger (fork length 46.7 mm, N=l9) than fry taken on the same date just below the pipeline rossing in shallow waters along the edges of the stream (Trail #2, 33.3 mm, N=81). Subsequent weekly samples from the Trail River were taken about 2 yards above Trail #1, and these fry ontinued to be ~xtremely large. This differene in growth for fry from two areas of the same stream again does not appear related to either benthos density or to temperature, sine both were lower at Trail #1. A omparison was made of the late-summer, seasonal growth of grayling fry from the Trail River and Stream 1 (Figure 5). Fry from the former were signifiantly larger than those from Stream 1. The mean fork length of fry from the Trail River was 46.7 mm (N=l9) on August 2, while on uly 3 fry from Stream 1 had a mean fork length of only 25.8 mm (N=l9). The more rapid growth apparent in the early weeks of life for Trail River fry is probably at least partly a result of the early break-up ourring there. On May 24, 1972, Stream 1 was still frozen -14-

26 ' -f - --~ ~ Table II. Comparison of the mean fork lengths of fry olleted from the Yukon North Slope on uly 3 -August 5, 1972, using the Multiple Range Test (Dunan 1955). Any two means enompassed by the same braket do not differ signifiantly. Temperatures and densities of benthi invertebrates are indiated. (Data marked by an asterisk (*) were olleted on uly 18, 1972). N is the number of fry in a sample. Mean is the mean fork length (in mm) of the sample. Mean no. of benthos is the mean number of benthi invertebrates, alulated from 6 Surber samples taken at the sampling site. P is the ranking number of 2 or more streams being ompared using the Multiple Range Test. Rp is the shortest signifiant range (p <.1). oation Stream 1 Trail #2 Crow Blow Deep Rq.pid Stream 13 Trail 111 Walki11g, Mean No. Standard benthos Water N Mean Deviation per ft2 Temp ] C * 17.* Shortest signifiant ranges (p <.1) for mean fork lengths. p Rp

27 ---~ ~---- solid, while the Trail River had some water beginning to flow underneath rotting ie. On une 2, the upper Trail River was ompletely open (water temperature=.5 C), whereas Stream 1 was just beginning to break up. It may be that grayling in Trail River were able to spawn somewhat earlier than grayling in Stream 1. From uly 3 to September 12, 1972, temperatures in the Trail River were onsistently higher than those in Stream 1 (Figure 5). This may be a further reason for the faster growth rate of Trail River grayling fry. Grayling fry from both the Trail River and Stream 1 first began to form sales at about 35 mm. This observation is similar to that made by MCart et al (1972) for Alaskan North Slope grayling. However, unlike fry from the upper Atigun River in Alaska, it is likely that almost all fry from both loations studied formed sales by the end of their first summer. Fry olleted from Stream 1 (N=48) and Trail River (N=35) on September 12, 1972 all were greater than 35 mm in length..22 Growth of Older Fish - In order to establish the reliability of growth rates determined from sale-based agings, both sales and otoliths were read for fish from the lower Firth River and Trout ake. In both ases disrepanies between the two methods were found similar to those desribed by MCart et f D al (1972). Figure 6 shows that for Firth River grayling both -16- r

28 \, - -(.) w ::: :::::> 1- <l: ::: w a.. ~ w A. -- -o \ \ \ \ \ \ \ \ \ \ \ Trail River e Stream 1 T T T T - E E - :r: 1- (!) z 6 w 4 _ ~ ::: z <l: w 2 ::E Trail River e Stream 1 B. AUGUST SEPTEMBER Figure 5. Comparison of late summer growth of fry from Stream 1 and Trail River. Temperature at the two study sites also shown.

29 I I I I I I I I I I I :I I methods gave similar mean fork lengths for ages one through 7, by whih time most fish have matured and growth slows abruptly. However, mean fork lengths determined from sales exeed those determined from otoliths in 6 out of 7 age groups beyond age 7. For the Trout ake sample, mean lengths determined by the two methods were similar through age 6, but in 4 of 5 ages beyond age 6, sale-based mean lengths exeeded those determined from otoliths (Figure 7). Furthermore, the maximum ages determined from otoliths (Firth River, age 22; Trout ake, age 15) far exeed those from sales (Firth River, age 14; Trout ake, age 11). These disrepanies between readings based on otoliths and sales are probably aused by the "dense edge" (Nordeng, 1961) developed by sales in later life, whih tends to obsure annuli on the sales of aged fish. Otoliths, on the other hand, usually ontinue developing reasonably lear annuli throughout the life of the fish. For this reason, all growth rates are based on ages determined by otoliths (Tables III, IV, V). Comparative growth urves for grayling from the three study areas are illustrated in Figure 8. Fish from the lake systems grow more rapidly than those from the Firth River. The population in ake 1 has the fastest growth rate. The growth of fish from the Firth River and Trout ake slows markedly by age 1 (at lengths of 348 mm and 359 mm respetively). Grayling from ake 1, however, ontinue to grow to about age

30 SAMPE SIZE Unsexed Fork ength (mm) Age Male % Female % Total Total Mean Range ;o Totals

31 ,,i l,, ll' ll 1 ~.l i-, I,.l,,. Table IV. Observed age-length relationship (based on otoliths) and age speifi sex ratios of grayling from Trout ake. SAMPE SIZE Age Fork ength (mm) Male % Female % Unsexed Total Mean Range I 1-' \. I Totals

32 -i Table V. Observed age-length relationships (based on otoliths) and age speifi sex ratios of grayling from ake 1. Perentages are alulated only from fish for whih sexes are available. SAMPE -SIZE Age Fork ength (mm) Male % Female % Unsexed Total Mean Range I tv 7 I Totals

33 ..11 ~~ r-: j ~ - il r-- r-: rrr: C ~ l ~] r- r-l ~ 'I ' ' r-l r-- :--) otoliths E E -:I:.,_;. 2 (!) z 1I... ~ a:: AGE 14 Figure 6. Comparison of age-length relationships determined from both sales and otoliths for grayling from the lower Firth River

34 -- ~ ~- -~- ----~---~--~ I l-- I l 4... E 3 E - :: I- (!) z w 2... io/ / / /'() / o" - -a- -o- -o- -,, ~., o otoliths o... E E ~ :::.. 1 r l_j 4 8 AGE Figure 7. Comparison of age-length relationships determined from both sales and otoliths for grayling from Trout ake f'

35 12 (length 381 mm). Grayling sampled in the Firth River had a greater maximum age than those in the lakes. One Firth River fish was aged at 22 years, while the oldest fish from Trout ake was 15 and from ake 1, Comparison with Growth in Other Areas - Figure 8 ompares growth of grayling from the Firth River with that of other areas in Alaska and the Canadian Arti. In omparison with these populations, ours are intermediate in their growth, but fish from the Firth River attain greater ages than those of any other area. As pointed out by MCart et al (1972) for Alaskan grayling, this may be an artifat of the method of aging (sale reading) used E E C r by other researhers. Data desribing the growth of grayling in other areas ame from the following soures: Great Slave ake, Bishop (1967); Great Bear ake, Miller (1946); Tangle akes, Roguski and Winslow (1969); Happy Valley Creek and Kuparuk River, MCart et al (1972)..3 Age at Maturity Table 7 gives data desribing the age at maturity for grayling from the three major study areas. Though data are sare for several age groups, it seems likely that fish from the two lakes first mature at an earlier age than fish from the Firth River. r, -21-

36 ---. ~ ~ ~ Males from Trout ake, and both males and females from ake 1, first mature at age 4. By age 7 all fish in Trout ake are mature, and those from ake 1 are all mature by age 6. Data for the Firth River are few, but no mature fish younger than age 7 was taken. By age 9 all fish, male and female were mature..4 Sex Ratios The total sample of grayling from the Firth River onsisted of almost exatly 5% males and 5% females (Table III). Trout ake grayling showed a slight predominane of females (53%), but this is not a signifiant departure from the expeted 1:1 ration (Table IV). the sex ratio of ake 1 grayling was 2. males to 1 female (Table V) and males were more abundant than females throughout the Age (Table V) and size (Figure 9) ranges sampled. ~ In the Firth River and Trout ake populations males tended to dominate among older, larger fish (Tables III, IV and Figure 9)..5 Egg Size, Feundity and Frequeny of Spawning - The eggs of mature females inrease in diameter during the ourse of the summer ~ " r (Figure 1). In mid-une, immediately after spawning, eggs are usually less than.5 mm in diameter. By mid-september eggs have inreased in diameter to approximately 1.7 mm. Eggs ontinue to grow during the winter, and just prior to spawning in spring, they attain a diameter of mm ' r I) (

37 j ~ r-:1 r-71 r ::7'"TI r-:1 r::-:1 m r-71 r ~1 r r-l r--"j r-l :-:-l :-l r-l Slave ake 4 - E.. 3 :: I (!) z I. _ ake - - -=: Firth River Happy Valley Creek Kuparuk River ~ a:: AGE Figure 8. Comparison of growth rates of grayling from the Firth River, Trout ake and ake 1 with those of other populations from Alaska and the Canadian Arti

38 Table VI. Feundity of mature, green female grayling from three loations in the Yukon Territory. Feundity N Mean Standard Error Range E t r l - Firth River Trout ake ake Total The mean feundity of samples of mature green females taken in August and September, 1972 was 8,967.8 eggs with a range of 477 to 14,429 eggs (Table VI). Regression analysis revealed that, for the ombined sample from the three loalities, there was no signifiant orrelation between lo feudnity and lo fork length (r=o.l5, N=2). It appears that one mature, female grayling spawn every year. None of the female grayling lassified as immature showed evidene of previous spawning (eg. retained eggs) and all of the older, larger females ontained maturing eggs (Table VII). Males apparently also spawn every year after they have attained maturity (Table VII) -23-

39 Table VII. Perent by age of male and female grayling from three loations on the Yukon North Slope whose gonads indiated that they had just spawned or would spawn the following spring. Ages were determined from otoliths. FIRTH RIVER TROUT AKE AKE 1 Age, Males Females Males Females Males Females N % Mature N % Mature N % Mature N % Mature N % Mature N % Mature I 8 N ~ I ~~ <' r: ~ r--'j I.. ""~ ~ r= rr= r- l -: u-:- r r----"1 ~ r---, ,! :-- :--l

40 ---,,...- l r- 1 ~: r--:-: r: r-: r- r-1 r-l ~I rr-: r-: , r--"1 ~ ---: - r---"1 en - N 1"1'1 n r l> en en ~ " 1"1' I NUMBER OF FISH CAUGHT 1 9' I I I I I I I I I I I I I I I I I... ~ :: ::... :I:... r :: l> < 1"1'1 I :: I~ CD CD CD 3 e. Q CD 3 CD - en en CD en - r 3 fl). 3 fl) CD CD id Figure 9. Numbers of males and females in various size lasses in samples from three loalities in the Yukon Territory. (II

41 .6 Spawning Period r~ In most Arti regions, the spawning period of grayling oinides with spring break-up, i.e., late May- early une. Weather and water onditions during this period restrited survey rews in our area, and onsequently data on times and sites of spawning are inomplete. Available data do show that spawning times vary from one loale to another. The first ripe grayling (a female) was taken on May 13, 1972 in the upper Firth River (i.e. above the aufeis). On that same r, date a spawned-out female was taken in oe Creek. Additional samples were taken from the upper Firth on May 17 (one female) and May 28 (a male and a female), all of whih were ripe. On une 17, 1972, three spawned out females were aught at the E E same loation. These data suggest that spawning in the upper Firth River ours during the latter half of May and early une. Grayling in the lower Firth River probably spawn about two weeks later, during mid-une. A green female was taken on une 8, E On une 13, 4 ripe males one ripe female and one spawnedr ~ out female were taken. Two days later, on une 15, a sample onsisting of 8 females and 3 males was taken; all the females and 2 of the males were spawned-out. Of a sample olleted E une 19 (2 females and 8 males), all fish exept two males were spawned-out. -25-,- i

42 On May 21, 1972 a sample of 4 green males and 4 green females was taken in Canoe Creek, a major tributary and overwintering site on the Babbage River about 1 miles below the falls. The next sample olleted there, a spawned-out male, was taken on uly 9, well after the spawning period. udging from these data, grayling in this stream probably spawn during the middle of une. No ripe grayling were olleted from any lakes. However, on une 14, 1972, a ripe male and female were observed engaged in ourtship behaviour in Trout ake outlet about 4 miles below the lake. These fish may have moved out of the lake to spawn. A olletion of 7 fish (3 males and 4 females) was taken from ake 1 on uly 2, all of whih were spawned out. From these data it is lear that spawning of grayling on the I '" r-, r~ f ' r- r-- r--, l3 r- 1 Yukon North Slope begins around the middle of May, and may ontinue until the latter part of une in some areas..7 Fry Emergene Considerable diffiulty was experiened in loating fry in any of the streams in our study area. Consequently no data are available on time of emergene from the onset of spawning. The first fry were enountered on uly 3, 1972 in Stream 1 at the pipeline rossing site. This was at least a month after spawning ourred, and by this time the fry were already quite -26- r,, r~; r

43 ~ ~~-~ ~ r : ~ ~ u - e - a: & ~ & 2 t - Q (!) (!) I 3. I I....& 2. t :.~ M fa ~ M thfoo M I.Ol ~~~ ~.. oo <.5-i da ali! a- Firth River Trout ake UNE I UY I AUGUST 1 ~ ake 1 SEPT. Figure 1. Seasonal development in egg size for mature grayling from three loations on the Yukon North Slope. I r~

44 large (mean fork length 25.8 mm, range 17-33, N=l9). Grayling fry usually hath from the egg days after spawning (Nelson, 1954; Peterson, 1968; Shallok, 1965). Depending upon water temperature. If the inubation period is similar for grayling from the Yukon North Slope, the first fry would appear in late une..8 Spawning and Rearing Areas r~ The distribution of grayling fry in our study area is sho~m ~j in Figure 4. Probably spawning areas, shown in Figure 11, l were determined on the basis of the presene of large numbers of fry, the ourane of ripe and spawned-out fish. arge numbers of fry were found in the Firth River at Castle Rok (about 1 miles above oe Creek), Stream 1 at the pipeline rossing, the Crow River at Peatbog Creek, at several loations in the lower Trail River and the Blow River, and in the viinity of the pipeline rossing in Deep Creek, Walking River, Rapid Creek and Stream 13. Ripe and spawned-out adult fish were found together in the Firth River above the aufeis field and r, at the head of the delta, although fry were not abundant in r- these areas. In addition, two ripe grayling, a male and a female, were observed in ourtship behaviour in Trout ake outlet on une 14, spawning site for grayling. This stream is therefore also a probable

45 -~ In most streams found to support grayling, both fry and older grayling were found together. In many areas, numbers were not suffiient to suggest spawning sites, and the fry may have moved down from spawning sites further downstream or in tributaries. Grayling fry generally oupy shallow, alm waters found along r r f l stream edges, in bakwaters, and in side hannels. During their first several weeks of life they tend to ongregate in small, dense shools. ater they beome more solitary and hide between roks in the stream bed. During late summer and early fall, r: fry in Stream 1 were ommonly seen trapped in shallow pools ut off from the main stream by lowered water levels or by ie. This appears to be a ommon plight of grayling fry as noted by Peterson (1968) and MCart et al (1972), and many fry must perish in this manner. Where fry and older fish were found together, fry tended to remain in very shallow waters while larger juveniles and mature fish remained in deeper areas. This is presumably a behavioural ~ f I b adapatation allowing all size lasses of grayling to inhabit a partiular stream without older fish annibalizing smaller ones. It has long been thought that grayling require lear water to spawn. Shallok (1965), however, found that grayling in the Chatanika River, Alaska, often spawn at the height of the spring -28- r-, ~. r.

46 "'TI - lo.., (1) - "".., r::r!l r::r -(1) Vl "'!l :::: : : lo!l.., (1)!l Vl -to.., lo..,!l -< : lo!l : lo,...,. :::r (1) -< 7' : z..,,...,. :::r Vl - "' (1) A 3.n 3:.n ] j d ~ g 1 : ~]

47 flood when waters are turbid and muddy. Observations on the r Yukon North Slope suggest that in most areas grayling also spawn during the spring flood in turbid waters. Only those fish in the upper Firth River, where the main soure of flow is ground water, have relatively lear water during the spawning period. A oarse sand or gravel substrate is required by spawning grayling (Nelson, 1954; Shallok, 1965). Suh substrates are very ommon in most streams along the Yukon North Slope, and were found r in all probable spawning sites shown in Figure Movements in Streams and Overwintering Areas Migratory patterns of grayling in our area remain almost totally u~known. Frequent high water levels and unfamiliarity with the area made study of grayling movements very diffiult. There is little doubt, however, that extensive and omplex movements do our in several of the drainages examined. Grayling movements are of neessity losely related to their overwintering sites. These sites are of speial importane to fish of the Yukon North Slope, beause during winter, most r~ streams freeze ompletely. Ie depths of up to 2.3 meters were enountered during late winter surveys in Marh, 1972 and April, oasional deep pools and perennial groundwater springs. of these springs are found near the headwaters of a few major Most The only areas on streams where there is any free water are l -29- r-

48 ~~~ Mountain Streams (see Figure 2), and all of them are known to be important overwintering sites for Arti har (Craig, 1973). In the upper Firth River, oe Creek and Canoe Creek, these open water sites are also used by arti grayling. In fall these two speies have been observed together in these areas, partiularly Canoe Creek. In spring, anadromous har vaate these overwintering sites and do not return until late summer. However, juvenile grayling and har remain all summer long. It appears that in spring, mature grayling leave the overwintering sites in the Mountain Streams to spawn. The almost total absene of grayling fry from the spring areas, and the presene of large numbers of fry in other areas, supports this speulation. A major exeption is the upper Firth River, where ripe and spawned-out fish ourred together in early spring, and where one grayling fry was found on September 25. This suggests that grayling do spawn in the upper Firth, although the exat loation remains unknown. Grayling fry were found throughout the entire length of the Firth River below the aufeis field but usually in small numbers. Only at "Castle Rok" (Figure 1) were numbers abundant enough to suggest a major spawning area. Fry in the rest of the river may have been washed down from this and other spawning sites, or perhaps grayling spawn sporadially throughout the length of the Firth River with few onentrated spawning areas. -3- I b b f' " f ~ / (

49 ~~~~~--~~-~---~~ Unlike grayling in the Sagavanirktok Drainage in Alaska (MCart et al, 1972), Firth River fish do not appear to utilize tributaries, either to spawn or to spend the summer. Only oe Creek is known to be inhabited by grayling, and again, no fry were taken at this loation. Mature grayling were taken all summer long (une 13 to September 9, 1972) at the gillnet station maintained at the head of the Firth Delta. Several ripe and spawned-out grayling were aught r, at this site on une 13-15, It is not known where these fish atually spawn, although small numbers of fry were aught in the delta throughout the summer. It is not known where grayling from the lower Firth River overwinter. The only possible overwintering site known in this area is a deep pool about 2 miles upstream of the pipeline rossing, whih ontained.5-.7 meters of free water on April 1, This water had a dissolved oxygen ontent of 9.4 ppm, suffiient to support overwintering fish. Perhaps other similar pools exist, and these provide overwintering l sites for grayling in the lower Firth River. It is also possible E r.-i that grayling migrate down from the spring area on the upper Firth in spring, and return in late fall to overwinter. of 17 grayling marked with a audal fin lip in the upper However, Firth, none was reovered in lower regions of the river. In addition, it is most unlikely that fry and small juveniles from r the lower Firth migrate this distane

50 ~~ In the Babbage River system, only the perennial ground water areas of the Canoe Creek-Wood Creek area ontain mature grayling onsistently throughout the summer and early fall. Very few mature fish were taken in the Babbage itself, although smaller juveniles and fry are very abundant. Even below the Babbage Falls, where a large, deep pool exists suitable as an overwintering area, only juvenile grayling were aught. - r= Some evidene exists to suggest that grayling in the Babbage drainage utilize some of the tributaries to the main river. On une 14, 1972, large numbers of mature grayling whih may have been moving up from the Babbage River to spawn, were observed in Philip Creek. Three of four fish aught on this date (mean fork length 37 mm, range ) were ripe. The Trail and Crow Rivers, both tributaries of the Babbage in its lower reahes, ontained large numbers of grayling fry. Throughout the summer mature grayling rarely were taken in either river, suggesting that after spawning, they return to other areas of the Babbage drainage to summer. r~ From the above data, it appears that mature fish in the Babbage system overwinter in a few speifi sites, probably usually r- _ assoiated with perennial ground water soures. The only suh site known to date is the Canoe Creek-Wood Creek area. These fish apparently leave the overwintering area and spawn either in the Babbage or in its tributaries suh as the Crow River, -32- r f / -~!

51 Trail River and Philip Creek. They then leave the spawning ~ areas and return to the viinity of their overwintering sites to spend the summer. It is not known where juvenile grayling and fry in the Babbage system overwinter. In the Crow and Trail Rivers several deep holes are known to exist, whih may provide overwintering sites for large numbers of small fish. Some also may move into the r-~ l is C Babbage River itself, whih is large enough that it may have areas of free water beneath the ie in winter. The Blow River and its major tributary, Rapid Creek, are known to ontain numerous grayling fry and juveniles, as well as some mature fish. The latter, however, did not appear nearly so abundant as in the Firth and Babbage drainages. No perennial ground water soures are known for the Blow River despite several winter surveys, so it is not known where fish overwinter. possible that they utilize lakes. Spawning areas are generally unknown, although the large numbers of fry suggest that several major spawning areas exist. In most Foothill Streams examined, the arti grayling was the r most abundant fish speies. All suh streams are assoiated with numerous tundra and foothill lakes, several of whih are known to support populations of grayling. It Grayling populations in the tundra streams frequently may be assoiated with the ( -

52 ~-~~~ lake populations. Streams usually ontained only juveniles r-- l and fry; mature grayling were rarely enountered. On the other hand, fry were found in only one lake examined (ake 1), and even in this lake they were sparse. It appears that grayling dwelling in the lakes may move into streams assoiated with suh lakes to spawn. Fry and juveniles remain in the streams during the summer, but mature fish return to the lakes. In fall, fry and juveniles must also return to the lakes to overwinter, sine none of the tundra streams (with the exeption of the Spring River, and no grayling were found there) have perennial ground water soures of flow, and all are believed too shallow to ontain free water during the winter. One suh foothill stream assoiated with lakes is Stream 1. This stream is loosely onneted to ake 1, ake 15 and ake 17, all of whih ontain large populations of mature grayling. Fry were found only in ake 1 and small juveniles were rare in all three lakes. Fry and juveniles were very abundant in Stream 1. Perhaps mature fish from these three lakes enter the stream to spawn. uveniles and one spawned-out female were found on uly 17, 1972 in the upper portions of the outlet of ake 15, whih enters Stream 1. l- ~ r -, ~ If the lake populations depend upon assoiated streams for their spawning and nursery areas, survival rates of fry and juveniles may vary onsiderably. Outlets to these lakes are unstable, -34- r, r'

53 the outlet to ake 17 was never observed to be ative, and grayling in this lake may be isolated for long periods. Similarly, the lower portions of the ake 15 outlet were very unstable qnd it is questionable whether fry and small juveniles ould r"" migrate bak into the lake to overwinter. The onnetion between ake 1 and Stream 1 is very omplex, flowing through at least 4 small, shallow tundra ponds and several miles of meandering stream. There is evidene, however, that grayling adults, juveniles and fry do, in fat, migrate upstream from Stream 1 into ake 1 to overwinter (Dirk de Graaf, Northern Engineering Servies, personal ommuniation)..1 Food Habits t E insets, fish, fish eggs, shrews and plant material. Items of no nutritional value, suh as stones, feathers and aribou hair, are also ommonly found in their stomahs. G Grayling are opportunisti in their feeding habits. Their diet is extremely variable and inludes bottom fauna, drift, terrestrial The stomah ontents of grayling from the lower Firth River (n=l36), Trout ake (n=lls), and ake 1 (n=78) are given in r Table VIII. Fish from all three areas relied heavily on surfae., insets for food. Firth River grayling also extensively utilized pleopteran nymphs, tipulid larvae and hironomid larvae. Grayling from the two lakes fed extensively on trihopteran larvae, amphipods and fish (Pungitius pungitius). l -35-

54 ~ - -- ~ Table VIII. Stomah Contents Pleoptera Trihoptera Ephemeroptera Coleoptera Tipulidae Simulidae Chironomidae Other diptera Stomah ontents of grayling from a Tundra ake, a Foothills ake and a Mountain Stream along the Yukon North Slope. N= number of times a partiular food item ourred; these values do not add up to the total number of fish in eah sample sine stomahs generally ontained more than one food item. %= perent of fish analyzed whih had eaten a partiular item. The ategory "surfae insets" indiates oasions when speifi omponents were not reorded. (* These empty stomahs are probably the result of holding the fish for 3-4 days before killing and analyzing them). nymphs adults larvae adults nymphs aquati terrestrial larvae larvae larvae pupae adults larvae adults Hymenoptera adults Hemiptera (orixidae) Arahnida (spiders, mites) Grasshoppers Surfae insets Mollusa (snails) Amp hi pods Plant material Shrews Fish Fish eggs Misellaneous (aribou hair, feathers, stiks, plasti ribbon, exuviae, roks) Parasiti nematodes Empty Total fish sampled Firth River N % , Trout ake N % * 4.4 \ ake 1 N % ' * ~- l- " ~-~ b li ~ r~ r

55 ~ r- r.11 Parasites From the onset pf the fish sampling program, it was lear that grayling taken from lake habitats frequently had large numbers of ysts in the body avity on their stomahs, while those found in streams were relatively yst-free. The ysts are probably aused by the larval stages of a tapeworm speies (Dr. D. Mudry, personal ommuniation). ake 1 grayling (n=97) had an average of 4 ysts per stomah. Those from Trout ake gr~yling (n=67) had about 3 ysts and only two stomahs from the Firth River (n=5) had one yst eah. This distribution probably reflets the availability, as food items, of intermediate hosts, ommon in lakes but rarely found in streams. r

56 ---~----- ITERATURE CITED Aquati Environments imited ate winter surveys of lakes and streams in Canada and Alaska along the gas pipeline routes under onsideration by Canadian Arti Gas Study imited. Unpublished report to Northern Engineering Servies imited. 183 p. ~ Bishop, F.G The biology of the Arti grayling, ThymaZZus artius (Pallas), in Great Slave ake. M.S. Thesis, University of Alberta. r : Bryan,.E., C.E. Walker, R.E. Kendal, M.S. Elson The n E influene of pipeline development on fresh water aquati eology in Northern Yukon Territory. Progress Report on Researh Conduted in ~ Craig, P.C Fall spawning and overwintering areas of fish populations b along routes of proposed pipeline between Prudhoe Bay and the Makenzie Delta. 36 p. Unpublished report to Northern Engineering Servies imited. E MCart, P., P. Craig and H. Rain Report on fisheries investigations ~ in the Sagavanirktok River and neighbouring drainages. Alyeska Pipeline Servie Company. 87 p. Report to Miller, R.B Notes on the Arti Grayling,,ThymaZZus signifer, from Great Bear ake. Copeia 4: l -38-

57 Nelson, P.R ife history and management of the Amerian grayling (Thymallus signifer triolor) in Montana.. Wild. Management 18(3): Nordeng, H On the biology of har (Salvelinus alpinus.) in Salanger, North Norway. Zoologi 1: Peterson, H.H The grayling Thymallus thymallus (.) of the Sundsvall Bay area. Institute of Freshwater Fisheries 48: Roguski, E.A. and P.C. Winslow Investigations on the Tanana River and Tangle akes grayling fisheries: migratory and population study. A Report of Progress Federal Aid in Fish Restoration Projet F-9-1, Alaska Department of Fish and Game. Shallok, E.W Grayling life history related to hydroeletri development on the Chatanika River in interior Alaska. M.S. Thesis, University of Alaska. l,~ l. r ' I b.~ l: -39- l~, I

58 PATE I. Male (bakground) and female (foreground) grayling from ake 1, Yukon Territory. PATE 2. Braided stream segment, Upper Firth River, Yukon Territory. PATE 3. Spring water soure tributary to Upper Babbage River. PATE 4. ooking downstream to large aufeis area on Upper Firth River.

59 PATE 5. Tundra Stream, Kugaryuk Creek, during nood stage. Note stability of banks. PATE 6. Beaded stream. Headwater tributary of Stream 1. PATE 7. Firth Camp ake illustrating shallow, weedy shoreline typial of Tundra akes. PATE 8. ake 17, a typial Foothills ake.