Lake Trout Monitoring Program 2019 Program Update

SR-20-02

May 2020 Lake Trout Monitoring Program 2019 Program Update Government of Yukon Fish and Wildlife Branch SR-20-02

Authors Cameron L. Sinclair, Pascale Savage, Caitlin January

Acknowledgments Robert Perry, Treharne Drury, Matt Clarke, Lars Jessup, Jaylene Goorts, Shawn Taylor, Ryan Drummond, Alex Francis, Traci Morgan, Mark O’Donoghue, Kenji Tatsumi, Alex Nadeau, Nathan Millar, Oliver Barker, Aaron Foos and our former staff and community partners who have worked with us over the years on this program.

Copies available from: Government of Yukon Department of Environment Fish and Wildlife Branch, V-5 Box 2703, Whitehorse, Yukon Y1A 2C6 Phone (867) 667-5652 Email:[email protected] Online:www.env.gov.yk.ca

Suggested citation: S��, C.L., P�� S��. A�� C�� J��.2020. Lake Trout Monitoring Program: 2019 Program Update (SR-20-02). Government of Yukon, Whitehorse, Yukon, Canada Summary

The Department of Environment conducts yearly population assessments of lake trout. This document provides an overview of the program as well as providing results from all individual lakes, as assessed from 2010 through 2019.

Lake Trout Monitoring Program: 2019 Program Update iii Table of Contents

Summary...... iii Table of Contents...... iv List of Figures ...... vi List of Tables...... vi Introduction...... 1 Overview...... 1 Key lake trout and lake whitefish biological characteristics ...... 1 Lake Trout...... 1 Lake Whitefish...... 2 Program Methods ...... 3 SPIN ...... 3 Length / Growth / Age...... 3 Habitat...... 3 Results...... 3 Data Uncertainties...... 4 Report Usage...... 4 Alsek River Watershed...... 6 Aishihik Lake 2017 ...... 7 Dezadeash Lake 2013 ...... 9 Pine Lake 2010...... 11 Sekulmun Lake 2010 ...... 13 Mackenzie River Watershed...... 15 Frances Lake 2017 ...... 16 Simpson Lake 2014...... 18 Toobally Lakes 2019 ...... 20 Watson Lake 2015 ...... 22 Yukon River Watershed...... 24 Atlin Lake 2014...... 25 Bennett Lake 2014...... 27 Braeburn Lake 2016 ...... 29 Caribou Lake 2011 ...... 31 Caribou Lake 2012 ...... 33 Chadburn Lake 2015...... 35 Ethel Lake 2011...... 37 Fish Lake 2010...... 39 Fish Lake 2012...... 41 Fox Lake 2013...... 43 Frenchman Lake 2012...... 45 Kathleen Lakes 2019 ...... 47 Kluane Lake 2013 ...... 49 Kusawa Lake 2014...... 51 Ladue Lake 2017...... 53 Lake Laberge 2016...... 55 Lewes Lake 2010...... 57 Little Atlin Lake 2015...... 59 Little Fox Lakes 2016...... 61 Little Salmon Lake 2015...... 63 Louise (Jackson) Lake 2011...... 65 Mandanna Lake 2013...... 67 Marsh Lake 2015 ...... 69 Mayo Lake 2013...... 71

Lake Trout Monitoring Program: 2019 Program Update iv Michie Lake 2017...... 73 Minto Lake 2014...... 75 Morley Lake 2018 ...... 77 Quiet Lake 2012...... 79 Snafu Lake (lower) 2010 ...... 81 Snafu Lake (Gazetted) 2018...... 83 Tagish Lake 2015...... 85 Tarfu Lake 2010...... 87 Ta’tla Mun 2011...... 89 Ten Mile Lake 2016 ...... 91 Teslin Lake 2016 ...... 93 Twin Lake (east) 2013...... 95 Twin Lake (west) 2013 ...... 97 Wolf Lake 2018 ...... 99 References...... 101

Lake Trout Monitoring Program: 2019 Program Update v List of Figures

Figure 1. Major Yukon Drainages...... 5

List of Tables

Table 1. Yukon lake size categories...... 3 Table 2. Major Yukon Drainages and watersheds...... 3

Lake Trout Monitoring Program: 2019 Program Update vi estimates and lake whitefish population information. Introduction The goals of this program are to provide scientific data on the status of fish populations and their health to aid in the management and The Department of Environment conducts yearly establishment of regulatory decisions. The Lake population assessments of lake trout (Salvelinus Trout Monitoring Program has also provided data namaycush and lake whitefishCoregonus ( to determine population trends to further support clupeaformis) as part of its’ delegated mandate population modelling in response to climate under the 1989 Canada-Yukon Freshwater change. Fisheries Agreement. These assessments The Lake Trout Monitoring Program in provide data to aid in fisheries management combination with Angler Harvest Surveys, the decisions. Fish Health program, and the Southern Lakes This document provides information on the Lake Trout Movement Project, forms the basis of Yukon Lake Trout Monitoring Program, including: Yukon’s Fisheries Program, providing accurate an overview of the program and its goals; the key data on the condition, life history and recreational biological characteristics of lake trout and lake us of Yukon’s freshwater fish stocks. whitefish; current scientific methodology used in the program; and the current results of all assessed lakes from 2010 through 2019. Key lake trout and lake whitefish biological characteristics Overview While the principle objective of this program is to Freshwater fisheries have long been determined providepopulation data to assist fisheries to be valued and integral components of Yukon management decisions, it is also important to society and culture (Department of Environment understand the key biological characteristics of 2010). lake trout and lake whitefish. It is also important Historically, fisheries have always played an to understand that Yukon lakes have been found important role in First Nations substance. to be low in productivity, as compared to southern However, in the early 1900’ commercial fisheries Canadian Lakes (Milligan 2018). Below is an became prevalent, to supply cheap and readily overview of these characteristics which includes: available food sources to miners associated with distribution; habitat; diet; age and growth, and the Dawson gold rush. Later, commercial fisheries spawning information. supplied food for workers developing the Alaska Highway. Historic records suggest that these Lake Trout commercial fisheries may have depleted many lake’s fish populations. Distribution Today, the value of recreational fishing to Lake trout are distributed across Canada and can Yukon residents remains evident as recreational be found throughout the Yukon (Scott and fishing pressures continue to grow (Sinclair and Crossman 1973). Current Yukon distribution of Perry 2019). For example, the 2015 National lake trout include all watersheds, with an absence Recreational Fishing Survey (Fisheries and noted in northwestern Beringia (Lindsey 1964). Oceans 2019) indicated that the amount of freshwater fish annually caught in Yukon was Habitat approximately 200,000. With this level of The key habitat requirements of lake trout are pressure, it is important for the Government of cold, clear waters with suitable temperature and Yukon monitor fish stocks to ensure the sport oxygen limits. While lake trout can tolerate a fishery remains healthy and sustainable. range of temperatures below 15⁰C, the optimum Since 1990, fish populations have been thermal range for their habitat lies within 8⁰C to annually assessed across the territory by the 12⁰C (Christie et. al. 1988). Within this range, the Department of Environment. In 2010, the Lake minimum dissolved oxygen level to support lake Trout Monitoring Program was launched, which trout is above 4 mg/L (Clark et al. 2004), with has been providing lake trout population

Lake Trout Monitoring Program: 2019 Program Update 1 optimal levels being greater than 7 mg/L (Evans European whitefishCoregonus ( lazarettos)(Mee 2005). et al. 2015). While these two species can exhibit physical differences (e.g. number and size of gill Diet rakers), they are often hard to distinguish with the Lake trout are a top predator in Yukon lakes, naked eye and require genetic analysis (Mee et al. feeding on a broad range of organisms from 2015, COSEWIC 2018). zooplankton and benthic invertebrates to fish (Scott and Crossman 1973). In Yukon lakes, Habitat stomach content analysis has continued to show While there is limited results on the defined that ciscoes and lake whitefish are a primary food habitat needs of lake whitefish, adults of this source for lake trout. species are predominately found in deep, cool lakes, with temperatures ranging from 8⁰C to Age and Growth 14⁰C (McPhail 2007). Throughout the Yukon Lake Lake trout in northern regions are known to be Trout Monitoring Program, lake whitefish have slow-growing and long-lived fish (Martin and been found to reside mainly in depths greater Oliver 1980).In Yukon, it is not uncommon to find than 20 m. Dissolved oxygen levels suitable for lake trout over 30 years of age, reaching upwards lake whitefish are found at levels greater than 4 of 50 (Environment Yukon 2010). Lake trout growth mg/L (Havens et al. 2014). rates are related to prey availability, particularly the presence or absence of lake whitefish and Diet ciscoes.Studieshavefoundthathigherdensities of Lake whitefishfeed on a variety of aquatic large lake trout (large-bodied morphs) occur in lakes organisms,focusingonzooplanktonasjuveniles, where lake whitefish are present, while lakes void and larger benthic invertebrates as adults (e.g. of whitefish and ciscoes (simple biological snails; McPhail 2007). In many systems lake communities) tend to support high densities of whitefish are known to also prey on smaller coarse small non-piscivorous lake trout (small-bodied fish(ScottandCrossman1973). By examining lake morphs;Carl2008). Evidencefromthe Lake Trout whitefish stomach content, we have seen evidence of Monitoring Program supports this observation. this, as well as observing that lake whitefish feed on Yukon’s‘small-bodied’ lake trout morphs have midges, mussels and caddisflies. been found in lakes absent of lake whitefish(e.g. KathleenLake),and‘large-bodied’ morphs have Age and Growth been found in lakes where lake whitefish are Similar to lake trout, lake whitefish in Yukon lakes present (e.g. Mayo Lake). are a slow growing and long-lived fish species (Scott and Crossman 1973). Lake whitefish can Spawning be found to live upwards of 35 years within Yukon Lake troutare fall-spawners and can be found lakes.Growth rates in lake whitefish are a factor of spawning inYukon throughout September and lake productivity, temperature, age at maturity and October, as water temperatures cool. Unlike many population density (Healy 1980, McPhail 2007). other salmonids, lake trout do not construct spawning nests. Lake trout typically spawn over Spawning coarse or angular clean rocks, depositing eggs Lake whitefish spawnin the fall, throughout into the cracks between the rock substrate September and October as temperatures cool, (McPhail 2007). While lake trout maturity is however exact spawning dates differ between dependant on the individual population and lakesandtemperatureranges,andmayoccurbi- morph-type, this species generally matures annually (McPhail 2007, Kennedy 1953). Spawning between 5 and 13 years of age. occurs at night and is associated with increased activity, prior to eggs settling on the substrate (Becker 1983). Lake whitefish tend to reach Lake Whitefish maturity faster than lake trout, with age at maturity between 4 and 10 years (McPhail 2007). Distribution Lake whitefish are a cold-water species, are widely distributed across Canada, mainly found in large, deep lakes and rivers (Scott and Crossman 1973). In Yukon lakes, where ciscoes are absent, lake whitefish have been found to co-occur with

Lake Trout Monitoring Program: 2019 Program Update 2 Program Methods Results

SPIN The results of the LakeTrout Monitoring Program are appended to this report as alphabetically The methodology used toeffectively assess lake categorized based upon watershed. Theseresults trout populations in the Yukon has evolved over provide a status overview of the lake trout and the years (Jessup and Millar 2011). Presently, the lake whitefish population within each lake, method used is the Summer Profundal Index including: estimated population size and density; Netting (SPIN) lake trout assessment model, length range and frequency; age distribution; developed by the Ontario Ministry of Natural temperature and dissolved oxygen profiles as well Resources and Forestry (Sandstrom and Lester as lake size classifications (Table 1); geographical 2009). This method was adopted by Environment and watershed location (Table 2, figure 1); access; Yukon in 2010 to replace the previous technique, and potential lake recommendations. which primarily sampled nearshore habitat (Jessup and Millar 2011). In Yukon, these surveys Table 1. Yukon lake size categories. are conducted in several lakes in the summer months from late June through early August. Size Range The SPIN method allows for the determination Size Category of harvestable lake trout population sizes through (ha) standardized gillnetting. Nets are set at varied depths across each lake, and the number of nets A < 100 differ depending on catch rates and area of lake with depths >10 m (see Sandstrom and Lester B 101 - 1,000 2009 for further information on methodology). By C 1,001 - 2,500 using this standardized method, Environment Yukon aims to produce results which will allow for D 2,501 - 5,000 detecting population changes over 25%. E 5,001 - 15,000

Length / Growth / Age F 15,001 - 65,000 During each survey, lake trout are measured for length (mm) and weight (g), with mortalities assessed to determine sex, maturity and age Table 2. Major Yukon Drainages and watersheds. (through the analysis of otoliths). This allows Environment Yukon to calculate growth rates, as well as define the age-class structure, for each Major Drainage Watershed population. Values such as these are an important tool when assessing population health, they Yukon Headwaters provide information on the size and condition of Upper Yukon these species at different life stages. Pelly Yukon River Stewart Habitat Central Yukon Porcupine In additionto determining population levels, the LakeTrout Monitoring Program also collects Upper Liard relevant habitat data.At a minimum, during each Mackenzie River Central Liard lake assessment bathymetric mapping is Peel and Southwestern conducted, and temperature (⁰C) and dissolved Beaufort oxygen (mg/L) profiles areconducted. As previouslydiscussed,laketroutandlakewhitefish Alsek Alsek River requiresuitableoxygenandtemperaturehabitats to survive.

Lake Trout Monitoring Program: 2019 Program Update 3 Data Uncertainties The results contained within this report should be interpreted with a measure of caution. Many of the population estimates have large uncertainties, herein expressed as population ranges. The larger the range, the greater the uncertainty. Additionally, many of the sampled lake trout and lake whitefish populations lack sufficient data for their age compositions. This makes it difficult to draw meaningful conclusions regarding population health.

The recommendations contained in this report have largely been based on the data and methods used in the program between 2010 and 2019. During this period, the programs principle direction was to improve certainties associated with population estimates through increased sampling (by an increase in net sets).Going forward, Yukon Fisheries will be refocusing some of it’s efforts by gathering additional information on fish age, their growth and habitats. This information will advance our understanding of these populations. For example, by improving our age data we will be able to further our analysis of growth and mortality rates. This will help us when determining lake-specific size and retention limits. Ultimately, this information will be incorporated when making management recommendations and will be added to fisheries reports in the years to follow.

Report Usage These results are designed to provide communities, public, First Nations, Renewable Resource Councils and fisheries managers with an overview of lake trout and lake whitefish population estimates for individual lakes. They have been formatted to enable our fellow stakeholers to pull individual lake results as necessary, while providing a short program overview. For further information regarding the Lake Trout Monitoring Program, stakeholders are encouraged to contact the Department of Environment Fisheries section by email at [email protected].

Lake Trout Monitoring Program: 2019 Program Update 4 146°W 144°W 142°W 140°W 138°W 136°W 134°W 132°W 130°W 128°W 126°W 124°W 122°W 120°W 118°W

MAJOR DRAINAGE AREAS of the

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140°W 138°W 136°W 134°W 132°W 130°W 128°W 126°W 124°W

Figure 1. Major Yukon Drainages

Lake Trout Monitoring Program: 2019 Program Update 5 Alsek River Watershed Alsek River Fish and Wildlife Branch Fisheries Report

Aishihik Lake 2017 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Alsek E The lake trout population in Aishihik Lake as observed during the 2017 SURFACE AREA ELEVATION survey, showed a moderate density of large-bodied lake trout, as compared to lakes within this size category. This population appears 37,720 ha 930 m healthy, despite high angling pressure. MAXIMUM DEPTH AVERAGE DEPTH 120 m 35.5 m Lake Whitefish SURFACE TEMPS. REGULATIONS Survey results indicate a healthy lake whitefish population within 11.1OC Conservation Waters Aishihik Lake. Whitefish populations are being monitored for recruitment on a yearly basis by Yukon Energy. To date little variation in SAMPLING DATES NET SETS recruitment has been observed. July 31 - Aug 4, 2017 140 Recommendation Location The recommendation for future surveys of the Aishihik Lake is to Aishihik Lake is located in southwest Yukon, improve population estimate power, by increasing net sets and within the Traditional Territory of the biological samples. This population should be monitored for any Champagne and Aishihik First Nations. It is cumulative effects of the hydro system and incorporate monitoring with located 43 km north of the Alaska highway, on hydro operations. the Aishihik Road.

Access and Use Program Overview Aishihik Lake is accessed by the Aishihik The Lake Trout Monitoring Program uses the Summer Profundal Index Road, with a government campground on the Netting (SPIN) method to provide information on lake trout and lake southern end, and Aishihik Village on the whitefish abundance, growth, age and density. north end. This lake serves as the Aishihik Generating Station reservoir, operated by This program surveys the two species by placing gill nets throughout Yukon Energy Corp, constructed in 1975. A the lake, taking into account both location and depth. Over time, this fish ladder on the southern end, currently type of sampling allows us to track population changes and evaluate the limits passage. health of these species.

SR-20-02 7 Lake Trout Lake Whitefish

Overview Overview During the 2017 survey of Aishihik Lake, a total of 134 lake During the 2017 survey, a total of 125 lake whitefish were trout were captured. These large-bodied lake trout ranged in sampled in Aishihik Lake. The size of these fish ranged from fork length from 225 mm to 889 mm, with an average length 235 mm to 540 mm, with an average fork length of 387 mm of 510 mm and weight of 1,738 g. Age structures, obtained and weight of 863 g. from 48 lake trout, showed an age variation from 4 through 32 years of age. 30

25 y

Population Estimate / Density c n

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The population of lake trout in Aishihik Lake, as assessed in e r F t the 2017 survey, was 66,500. However our confidence in n 15 e c r e

the estimate was weak (estimate range: 40,700 to 93,300). P This estimate equates to an average density of 4.5 lake trout 10 per hectare. 5

18 0 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 16 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7

14 Fork Length (mm) y c n

e 12 u q e r 10 F t n

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4 Temperature and dissolved oxygen profiles were obtained 2 on August 1. The temperature profile displayed a 0 thermocline between 10 m and 18 m, followed by a slow 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0 decline to 72 m. The oxygen profile was stable throughout 1 the water column. Overall, optimal lake trout habitat existed Fork Length (mm) throughout the entire water column.

900

800 Temperature (C), Dissolved Oxygen (mg/L) 700 0.0 5.0 10.0 15.0 0.0 ) 600 mm ( h t 500 g

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200

100 30.0

0 ) m 0 5 10 15 20 25 30 35 ( h

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Age (year) e D

50.0

60.0

70.0

For more information, please contact Temperature

Department of Environment 80.0 Dissolved Oxygen Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

8 Fish and Wildlife Branch Fisheries Report

Dezadeash Lake 2013 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Alsek E Dezadeash Lake is a shallow, productive lake with a healthy population ELEVATION of large-bodied lake trout. This finding agrees with previous sampling SURFACE AREA results. This population may be at risk due to decreasing thermal habitat 7968 ha 690 m availability as water temperatures increase with climate change.

MAXIMUM DEPTH AVERAGE DEPTH 7.4 m 4.1 m Lake Whitefish The lake whitefish population within Dezadeash Lake was healthy with SURFACE TEMPS. REGULATIONS O a high relative density. Of interest, this lake also contains Squanga 8.54 C Special Management Whitefish, a species listed federally as one of Special Concern. SAMPLING DATES NET SETS June 3-9, 2013 140 Recommendation The recommendation from the 2013 survey is to slightly increase the Location number of biological samples in future surveys to improve our certainty Dezadeash Lake is in southwestern Yukon, in the population status. This uniquely shallow lake should be monitored within the Traditional Territory of the for habitat changes duetoincreasingtemperaturesassociatedwith Champagne and Aishihik First Nations. This climatechange. lake lies on the eastern border of Kluane National Park and Reserve, approximately 40 km south of Haines Junction. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Access to Dezadeash is along the Haines whitefish abundance, growth, age and density. Road (Hwy 3). This lake has a government campground near the southern end with an This program surveys the two species by placing gill nets throughout accessible boat launch, as well as several the lake, taking into account both location and depth. Over time, this residences. type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 9 Lake Trout Lake Whitefish

Overview Overview During the 2013 survey, a total of 228 lake trout were A total of 629 lake whitefish were captured during this captured. Fork lengths ranged from 395 mm to 829 mm, survey. They ranged in fork length from 208 mm to 510 mm, with an average length of 642 mm and weight of 3,323 g. with an average length of 307 mm and weight of 386 g. Age Age structures were obtained from 36 lake trout during the structures were interpreted from 139 lake whitefish. Ages 2013 survey, with ages ranging from 6 to 24 years. ranged between 3 and 16 years. This population appears healthy. Population Estimate / Density The lake trout population in Dezadeash Lake was estimated 35 at50,205 indiviuals. However our confidence in the estimate 30 was weak (estimate range: 34, 536 – 66,694). This y c 25 n corresponded to a density of 6.3 lake trout per hectare. e u q e r

F 20 t n e

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16 e P 14 10

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q 0 e r 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 F 0 2 5 7 8 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 t 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 n e c r

e 6 Fork Length (mm) P

2 Temperature and Oxygen

0 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 Temperature and dissolved oxygen profiles were taken from 1

Fork Length (mm) the middle of the lake on June 9, 2013. Both temperature and dissolved oxygen were consistent throughout the water column. This is expected in a system as shallow as 800 Dezadeash Lake. 700

) 600 mm

( Temperature (C), Dissolved Oxygen (mg/L) 500 h t 0 5 10 15 g n e 0.0

L 400 k r o F 300 1.0 200

100 2.0 0 0 5 10 15 20 25 30

Age (year) 3.0 ) m ( h t

p Temperature e

D 4.0

Dissolved Oxygen 5.0 For more information, please contact Department of Environment 6.0 Fish and Wildlife, Fisheries [email protected] 7.0 867-667-5652

SR-20-02 Table of Contents

10 Fish and Wildlife Branch Fisheries Report

Pine Lake 2010 Lake Trout Monitoring Program

Lake Information Overall Status Lake Trout Results indicate that Pine Lake has a critically small population of lake WATERSHED LAKE CLASS trout. Evidence suggests that levels of lake trout in Pine Lake are Alsek B depleted and the population may have collapsed. SURFACE AREA ELEVATION 603 ha 625 m Lake Whitefish MAXIMUM DEPTH AVERAGE DEPTH Pine lake contains a healthy population of lake whitefish, which are 28 m 14.7 m likely the main diet for other predators in this lake, such as northern pike and burbot. SURFACE TEMPS. REGULATIONS Not available Special management Recommendation SAMPLING DATES NET SETS The recommendation from the 2010 survey is to minimize all lake trout July 5-7, 2010 27 harvest, in an effort to naturally rebuild this population. This process may take many years to occur. A secondary survey is recommended in Location 2020 to determine if the population is responding to newly established Pine Lake is near the community of Haines regulation changes. Junction along the Alaska Highway. It is in the Traditional Territory of the Champagne and Aishihik First Nations. Program Overview Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Pine Lake is accessed by the Alaska Highway Netting (SPIN) method to provide information on lake trout and lake via a popular government campground with whitefish abundance, growth, age and density. an accessible boat ramp. There are also several permanent residences along the This program surveys the two species by placing gill nets throughout lakeshore. the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the

SR-20-02 11 Lake Trout Lake Whitefish Overview Overview Only two lake trout were captured during this survey, During this survey 66 lake whitefish were captured, ranging averaging 503 mm in length (as measured to the fork) and from 460 mm to 620 mm in length (as measured to the 1600 g in weight. Age structures were only taken from one fork), with an average length of 528 mm and weight of of these fish, which was determined to be 23 years old. 2,287 g. Twenty-four lake whitefish were sampled for age, Population Estimate / Density which showed a range from 11 to 24 years old, with an average age of 16. Due to the limited number of lake trout captured during this survey, the population estimate is uncertain. The density calculated shows a potential of 1.4 lake trout per hectare, 18 however there is little confidence in this estimate. 16 Nevertheless, the limited number of lake trout captured 14 suggests the population may have undergone a collapse. 12 y The low numbers captured do not allow for accurate catch c n

e 10 u q

frequency or age comparisons. e r

F 8 t n e c r

e 6 P

Fork Length (mm) Temperature and Oxygen

Temperature and oxygen profiles were not assessed during the 2010 survey as this specialized equipment was not available.

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

12 Fish and Wildlife Branch Fisheries Report

Sekulmun Lake 2010 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS Results from sampling indicated Sekulmun Lake has a healthy Alsek D population of large-bodied lake trout. Due to its inaccessibility, the lake SURFACE AREA ELEVATION receives minimal recreational pressure. This may account for the healthy population. 4985 ha 921 m

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 53 m 28 m We could not determine the status of lake whitefish populations during SURFACE TEMPS. REGULATIONS the 2010 survey, as only a single lake whitefish was captured. Given the Not available Conservation waters small sample, the population may not be large. Additional specices that are present in the lake inlucde: round whitefish, pygmy whitefish, arctic SAMPLING DATES NET SETS grayling, northern pike, burbot and longnose suckers. August 18-21, 2010 86 Recommendation Location The recommendation from the 2010 survey is to increase the number of net sets andbiological samples for age analysis for future surveys. Sekulmun Lake lies to the west of Aishihik Lake, southwest of Aishihik Village. The lake is in the Traditional Territory of the Champagne and Aishihik First Nations. Program Overview The Lake Trout Monitoring Program uses the Summer Profundal Index Access and Use Netting (SPIN) method to provide information on lake trout and lake Sekulmun Lake is accessed via a trail from whitefish abundance, growth, age and density. Aishihik Village, as well as by the Sekulmun This program surveys the two species by placing gill nets throughout River, which connects to Aishihik Lake. the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 13 Lake Trout Lake Whitefish

Overview Overview Sixty lake trout were captured during this survey, averaging During this survey only one lake whitefish was captured, 506 mm in length (as measured to the fork) and 2,345 g in which does not allow us to accurately estimate population weight. Age structures were not obtained during this survey. status.

Population Estimate / Density Temperature and Oxygen The population of lake trout is estimated at approximately 18,651 (ranging between 10,303 – 27,303). This Temperature and oxygen profiles were not assessed during corresponds with a density of 3.7 lake trout per lake hectare. the 2010 survey as this equipment was not available at the time.

y 6 c n

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P 2

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 6 2 5 8 6 3 9 2 5 8 1 4 7 0 3 9 1 4 7 0 3 9 2 5 2 5 6 6 6 8 2 2 3 3 3 4 4 4 5 5 5 7 7 7 8 8 8 9 9 Fork Length (mm)

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

14 Mackenzie River Watershed Upper Liard, Central Liard, Peel and Southwestern Beaufort Sea Fish and Wildlife Branch Fisheries Report

Frances Lake 2017 Lake Trout Monitoring Program

Lake Information Overall Status

WATERHSED LAKE CLASS Lake Trout Upper Liard E In accordance with 2017 survey results, the lake trout population in Frances Lake, is a healthy, large-bodied population. The lake had a SURFACE AREA ELEVATION moderate density and healthy age demographic of lake trout. 9,941 ha 734 m

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 93 m 31 m The population of lake whitefish in Frances Lake is a healthy population, with a wide age range. SURFACE TEMPS. REGULATIONS O 17.4 C Conservation Waters Recommendation SAMPLING DATES NET SETS The recommendation for future surveys is to determine recreational Aug 11 - 15, 2017 149 angling pressure by conducting an Angler Harvest Survey. If this lake is sampled by the SPIN method again, an increase in biological data for Location age analysis will provide more information on the health of this Frances Lake is located in southeast Yukon, population. approximately 171 km north of Watson Lake, along the Robert Campbell Highway. This lake lies within the Kaska Dena Council Traditional Program Overview Territory. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Access and Use whitefish abundance, growth, age and density. Frances Lake is accessed by a government campground on the west arm, as well as a This program surveys the two species by placing gill nets throughout public boat launch and wilderness lodge, the lake, taking into account both location and depth. Over time, this located on the southern end. There are a few type of sampling allows us to track population changes and evaluate the cabins located along the shoreline. health of these species.

SR-20-02 16 Lake Trout Lake Whitefish

Overview Overview During the 2017 survey of Frances Lake, a total of 106 lake During the 2017 survey, a total of 140 lake whitefish were trout were captured. These large-bodied lake trout ranged in captured in Frances Lake. The size range of these fish fork length from 154 mm to 917 mm with an average length ranged from 240 mm to 617 mm, with an average fork of 476 mm and weight of 1,838 g. Age structures, obtained length of 416 mm and weight of 1,181 g. The 74 sampled from 46 lake trout, showed an age variation from 4 through lake whitefish had an age range from 4 to 20 years of age. 40 years.

25% Population Estimate / Density 20% The population of lake trout in Frances Lake, as assessed in y the 2017 survey, was37,551 (estimate range: 19,189 to c n

e 15% u q

56,525). This estimate equates to an average density of 3.4 e r F t n lake trout per hectare. e c

r 10% e P

12% 5%

10% 0% 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 25 27 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 Fork Lenth (mm) 8% y c n e u q e r

F 6%

t Temperature and Oxygen n e c r e P 4% Temperature and dissolved oxygen profiles were obtained on August 15. The temperature profile displayed a steep decline 2% from the surface through 30 m, decreasing from 17oC to 5oC. From 30 m to the bottom the temperature remained 0% 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 constant. Dissolved oxygen was stable across the profile. 6 6 6 6 25 27 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 Fork Lenth (mm) Overall, optimum lake trout habitat ranged from 15 m to 90 m.

Temperature (C), Dissolved Oxygen (mg/L) 1000 0 5 10 15 20 0 900

800 10

) 700 mm ( 600 20 h t

g 500 n e

L 30 400 k r o

F 300 40 Temperature

200 ) m ( Dissolved

100 h

t 50 Oxygen p e

0 D 0 5 10 15 20 25 30 35 40 45 60 Age (year)

For more information, please contact 90 Department of Environment 100 Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

17 Fish and Wildlife Branch Fisheries Report

Simpson Lake 2014 Lake Trout Monitoring Program

Lake Information Overall Status

WATERHSED LAKE CLASS Lake Trout Upper Liard C In accordance with the 2014 survey, the results of Simpson Lake showed a moderate density of large-bodied lake trout. This population SURFACE AREA ELEVATION appears healthy. 2,180 ha 694 m

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 58 m 38 m The 2014 survey of Simpson Lake captured few lake whitefish, an indication the population may be small. However, round whitefish were SURFACE TEMPS. REGULATIONS captured in larger numbers. This may be an important prey species for 16.5OC General waters lake trout in this lake. SAMPLING DATES NET SETS June 24-27, 2014 69 Recommendation The recommendation for future surveys is to perform an Angler Harvest Survey on Simpson Lake to determine recreational pressure. In addition, Location if this lake is surveyed in the future, net sets should be increased to Simpson Lake is located within the Liard ensure greater precision in the population estimate. watershed in south eastern Yukon. This lake lies within the Traditional Territory of the Kaska Dena Council. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Simpson Lake is accessed along the Robert Netting (SPIN) method to provide information on lake trout and lake Campbell highway, 73 km north of Watson whitefish abundance, growth, age and density. Lake. There is a government campground at This program surveys the two species by placing gill nets throughout the southern end of the lake, with an the lake, taking into account both location and depth. Over time, this accessible boat ramp. type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 18 Lake Trout Lake Whitefish

Overview Overview During the 2014 Simpson Lake survey a total of 46 lake Only 8 lake whitefish were captured, ranging in length from trout were sampled. These ranged in size (fork length) from 364 mm to 570 mm in length, with an average fork length 337 mm to 812 mm, with an average length of 594 mm and and weight of 501 mm and 2,000 g. Age structures were weight of 2,784 g. Age structures were obtained from seven not obtained. fish, with an age range from 5 to 30 years. 50 45 Population Estimate / Density 40

y 35 The population of lake trout in Simpson Lake, as assessed c n e

u 30 q during the 2014 survey was estimated at7,240 (estimate e r F 25 t n range: 3,663 – 10,936). This equates to a density of 3.3 lake e c

r 20 e P trout per hectare. 15 10 5 16 0 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 14 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 Fork Length (mm) 12 y c n

e 10 u q e r F 8 t n

e Temperature and Oxygen c r

e 6 P 4 Temperature and dissolved oxygen profiles were taken in the

2 main basin, near the center of the lake on June 27, 2014. The temperature profile displayed a sharp decrease in 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 2 7 2 7 00 50 2 7 2 7 temperature from the surface to 10 m, then steadily 6 6 6 6 300 3 350 3 400 4 450 4 500 5 550 5 7 72 7 77 800 8 850 8 900 9 950 9 1000 decreased to 20 m, where it remained constant through the Fork Length (mm) remaining water column. Dissolved oxygen levels gradually decreased with depth, however they remained optimal for

700 lake trout throughout the water column.

600 Temperature (C), Dissolved Oxygen (mg/L) 0.00 5.00 10.00 15.00 20.00 0

) 500 mm ( h t 400 g n e

L 10 k r 300 o F

200

20 100

Temperature 0 ) m ( Dissolved Oxygen 0 5 10 15 20 25 30 35 h t 30 p e

Age (year) D

50 For more information, please contact

Department of Environment 60 Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

19 Fish and Wildlife Branch Fisheries Report

Toobally Lakes 2019 Lake Trout Monitoring Program The 2019 survey was performed at Upper Toobally and Lower Toobally Lake.

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Central Liard C As estimated from the 2019 survey, the lake trout populations in Upper SURFACE AREA ELEVATION (U) and Lower (L) Toobally, are heathy and moderately sized. The 1170(U),1081(L) ha 623 m oxygen levels were found to be at the low end of optimal for lake trout in Lower Toobally, however there is no indication that this population is MAXIMUM DEPTH AVERAGE DEPTH currently being limited by these low levels. 118(U),60(L) m 22.8(U), 16.7(L) m

SURFACE TEMPS. REGULATIONS Lake Whitefish 17.3OC(U)17.3OC(L) General waters The lake whitefish populations in the Toobally Lakes also appear healthy, at a low to moderate level. SAMPLING DATES NET SETS July 24-28, 2019 45(U),44(L) Recommendation The recommendation for future surveys of the Toobally Lakes is to Location continue working with the sport fishing lodge to determine their angling The Toobally Lakes (Upper and Lower) are pressure and to monitor dissolved oxygen levels. Additional age analysis located in the southeastern corner of Yukon, wil assist in providing more information on the health of this population. approximately 140 km east of town of Watson Lake. These lakes lie within the Traditional Territory of the Kaska Dena Council. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake The Toobally Lakes are accessible by fly-in whitefish abundance, growth, age and density. only, with an established outfitting lodge operating with cabins at each lake. There is no This program surveys the two species by placing gill nets throughout road access, nor additional private residences the lake, taking into account both location and depth. Over time, this on these lakes. type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 20 Lake Trout Lake Whitefish

Overview Overview During the 2019 survey of Upper (U) and Lower (L) Toobally A total of 55 (U) and 29 (L) lake whitefish were captured in Lakes, a total of 68 (U) and 61 (L) lake trout were captured. 2019. These fish ranged in size from 215 to 460 mm (U), The lake trout ranged in size from 240 to 915 mm (U), 269 196 to 509 mm (L), with an average fork lengths of 388 (U) to876 mm (L), with an average fork lengths of 625 mm (U) and 509 (L). This resulted in average weights of 859 g (U) and 672 mm (L). This resulted in average lake trout weights and 932 g (L). Ages were interpreted from 68 lake whitefish of 3243 g (U) and 4342 g (L). Age structures were taken (24L, 44U). Ages ranged from 5 to 22, with the average age from 49 lake trout (25(L), 24(U)). Ages ranged from 5 to 45, in the Lower lake of 9 and the Upper lake of 11. with the average age in the Lower lake of 15 and for the Upper lake at 14. 45.0

40.0

Population Estimate / Density 35.0

y 30.0

The population of lake trout within the Toobally Lakes, as c n

e Upper u estimated during the 2019 survey indicated a population in q 25.0 e

r Lower F

Upper Toobally of4,564 (estimate range: 2,589 – 6,614) and t n 20.0 e c r in Lower Toobally of4,235 (estimate range: 2,419 – 6,121). e P 15.0 This corresponded to densities of 3.9 lake trout /ha in both lakes. 10.0 5.0 18 0.0 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 16 0 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1

14 Fork Length

12 Upper y c Lower n e u 10 Temperature and Oxygen q e r F t n 8 e c r

e Temperature and dissolved oxygen profiles were taken in P 6 both the upper and lower lakes. Profiles in both lakes display 4 a sharp thermocline from 5 m to 12 m, with temperatures

2 decreasing gradually throughout the rest of the water column. Overall, Upper Toobally provided optimum lake trout habitat 0 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 from 8 m to lake bottom, with Lower Toobally providing 1 Fork Length (mm) suitable habitat from 8 m to 20m, with tolerable, but low

800 oxygen levels below 20m.

Upper Toobally Lower Toobally Temperature (C), Dissolved Oxygen (mg/L) 600 0 5 10 15 20 Temperature (C), Dissolved Oxygen (mg/L) 0 0 5 10 15 20 0

Upper 400 10 Lower 10 Fork Length(mm)

20 20 200 Temperature Temperature ) m ) (

Dissolved m h (

t 30

p Oxygen Dissolved h t e 30 p

D Oxygen e

0 D

10 20 Age 30 40 40 40

50 For more information, please contact 50 Department of Environment 60 Fish and Wildlife, Fisheries 60 [email protected] 867-667-5652

SR-20-02 Table of Contents

21 Fish and Wildlife Branch Fisheries Report

Watson Lake 2015 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Upper Liard C The lake trout population in Watson Lake displayed a lower than SURFACE AREA ELEVATION average density, when compared to Yukon lakes of simiar size and 1,410 ha 680 m productivity. This may indicate that the lake trout population in Watson Lake is small and at risk of depletion if fishing pressures increase. MAXIMUM DEPTH AVERAGE DEPTH 32 m 14.5 m Lake Whitefish SURFACE TEMPS. REGULATIONS Results from the 2015 survey indicated a healthy population of lake 17.3OC Special management whitefish, with considerable habitat for this species.

SAMPLING DATES NET SETS July 7-12, 2015 46 Recommendation The recommendation for future surveys of Watson Lake is to increase the number of net set and collection of age structures for analysis. This Location will help increase out ability to detect changes in population and provide Watson Lake is located approximately 4 km information on the health of this population. north of the community of Watson Lake, in southeastern Yukon, along the Robert Campbell highway. This lake lies within the Program Overview Kaska Dena Council Traditional Territory. The Lake Trout Monitoring Program uses the Summer Profundal Index Access and Use Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Watson Lake is a popular recreational lake with access available at the government This program surveys the two species by placing gill nets throughout campground and along the Robert Campbell the lake, taking into account both location and depth. Over time, this highway. The Watson Lake airport is situated type of sampling allows us to track population changes and evaluate the on the north shore, it was constructed just health of these species. prior to the development of the Alaska Highway.

SR-20-02 22 Lake Trout Lake Whitefish

Overview Overview During the Watson Lake 2015 survey a total of 41 lake trout A total of 415 lake whitefish were captured during the 2015 were captured, ranging in size (fork length) from 182 mm to Watson Lake survey, ranging in size from 219 mm to 472 830 mm, with an average length of 513 mm and weight of mm in length. The average fork length was 396 mm and 1,728 g. Age Structures were obtained from 14 lake trout. weight was 808 g. Age structures were obtained from 61 Ages ranged from 6 to 25 years. lake whitefish. Ages ranged from 4 through 31 years.

45 Population Estimate / Density 40

The population estimate of lake trout in Watson Lake was y c 35 n e

4,105 (range: 1,831 – 6,445). This equated to a density of u

q 30 e r

2.9 large-bodied lake trout per hectare. F

t 25 n e c

r 20 e P 15 18 10 16 5 14

y 0 c 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 n 12 e 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 u 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 q

e 10 r

F Fork Length (mm) t n

e 8 c r e P 6 Temperature and Oxygen 4 2 Temperature and dissolved oxygen profiles were taken on 0 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 July 23, 2015. The temperature profile displayed a sharp 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 thermocline from 8 m to 10 m. Temperature slowly declined Fork Length (mm) throughout the rest of the water column. Dissolved oxygen was stable, decreasing with depth. Given the observed temperatures, suitable lake trout habitat was found between 700 10 m and lake bottom.

600 Temperature (C), Dissolved Oxygen (mg/L) 0.00 10.00 20.00

) 500 0 mm ( h

t 400 g n

e 5 L k

r 300 o F

200 10

100 15

0 ) m

0 5 10 15 20 25 30 ( h

t 20

Age (year) p e D

25 Temperature

Dissolved Oxygen 30

35 For more information, please contact Department of Environment 40 Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

23 Yukon River Watershed Yukon Headwaters, Upper Yukon, Pelly, Stewart, Central Yukon and Porcupine drainages Fish and Wildlife Branch Fisheries Report

Atlin Lake 2014 Lake Trout Monitoring Program The 2014 Atlin Lake survey was conducted as a joint effort with the Taku River Tlingit First Nation

Lake Information Overall Status WATERSHED LAKE CLASS Yukon Headwaters F Lake Trout In accordance with the 2014 survey results, the lake trout population in SURFACE AREA ELEVATION Atlin Lake is of the large-bodied form and population is healthy. 58, 792 ha 670 m Although this is a popular recreational angling destination, due to the MAXIMUM DEPTH AVERAGE DEPTH size of the lake, its lake trout population is larger and can sustain greater pressure. 283 m 85.6 m

SURFACE TEMPS. REGULATIONS Lake Whitefish 21OC Special Management Given the 2014 survey results, the population of lake whitefish in Atlin SAMPLING DATES NET SETS Lake appears to be small. Care needs to be taken to ensure the August 5-13, 2014 150 population remains healthy. Location Recommendation Atlin Lake is a large, deep lake primarily The recommendation for future surveys is to maintain the sampling located in north-western British Columbia, protocols implemented in 2014, by using the same number of net sets. with only the northern end extending into This number of sets gave suitable confidence for the population southern Yukon. It is approximately 120 km estimate. south-east of Whitehorse. Altin Lake forms the headwaters of the Yukon River drainage. Atlin Lake lies within the Traditional Territories of the Taku River Tlingit and Carcross/Tagish Program Overview First Nations. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Access and Use whitefish abundance, growth, age and density. Atlin Lake is accessed via the Atlin Road and the town of Atlin, BC, with accessible boat This program surveys the two species by placing gill nets throughout ramps. Atlin is a popular recreational fishery. the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 25 Lake Trout Lake Whitefish

Overview Overview During the 2014 survey, a total of 140 lake trout were During this survey, 11 lake whitefish were captured in Atlin captured, ranging in size from 248 mm to 960 mm in fork Lake. The lake whitefish captured ranged from 429 mm to length. Sampled lake trout had an average length of 499 520 mm, with an average length of 482 mm and weight of mm and weight of 1,677 g. Age structures were obtained 1,479 g. No aging structures were obtained from these fish. from 68 individuals. Ages ranged from 5 to 22 years old.

60 Population Estimate / Density The population of lake trout within Atlin Lake was estimated 50

tobeat243,000 (estimate range: 142,808 – 346,689). This y c 40 n e equates to a density of 4.2 lake trout per hectare. u q e r

F 30 t n e c r e

20 P 20

18 10 16

14 0 y c 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0

n 12 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 e 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 u q

e 10 r

F Fork Length (mm) t

n 8 e c r

e 6 P

4 2 Temperature and Oxygen 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 2 7 2 7 00 50 2 7 2 7 6 6 6 6 300 3 350 3 400 4 450 4 500 5 550 5 7 72 7 77 800 8 850 8 900 9 950 9

1000 Temperature and dissolved oxygen profiles were taken at Fork Length (mm) two locations, one in the northern section of the lake and one adjacent to Atlin, BC. Temperatures declined slowly over the first 25 m. There was a defined thermocline observed in the 800 northern section between 25 m and 30 m, however no sharp

700 thermocline was evident at the Atlin, BC sampling locaiton. Temperature and dissolved oxygen levels were suitable for 600 ) lake trout and whitefish from the surface to 60 m. mm

( 500 h t g n e 400 Northern section Atlin, BC L k r

o Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L)

F 300 0.00 5.00 10.00 15.00 0.00 5.00 10.00 15.00 0 0 200

100 10 10

0 0 5 10 15 20 25 20 20

Age (year)

) 30 ) 30 m m ( ( h h t t p p e e

D 40 D 40

50 50 For more information, please contact 60 60 Department of Environment Temperature Temperature Dissolved Oxygen Dissolved Oxygen Fish and Wildlife, Fisheries 70 70 [email protected] 867-667-5652

SR-20-02 Table of Contents

26 Fish and Wildlife Branch Fisheries Report

Bennett Lake 2014 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Yukon Headwaters E Lake Trout In accordance with the 2014 survey results, the lake trout population in SURFACE AREA ELEVATION Bennett Lake is healthy. The lake has a moderate density of lake trout 9068 ha 656 m when compared to lakes of similar size. This finding is consistent with previous surveys, which used alternate sampling methods. MAXIMUM DEPTH AVERAGE DEPTH 123 m 62 m Lake Whitefish SURFACE TEMPS. REGULATIONS The population of lake whitefish in Bennett Lake appears small. Given 14.2OC Special Management the low productivity of the lake, this result may be normal. Nevertheless, as this is a large and deep lake, there is a potential that this survey did SAMPLING DATES NET SETS not adequately sample lake whitefish. July 15-24, 2014 136

Location Recommendation Bennett Lake is located within the southern The recommendation for future surveys is to continue using the same lakes complex in southern Yukon and is number of net sets performed in 2014, as we were capable of adjacent to the community of Carcross. generating a reliable population estimate. Bennett Lake lies within the Traditional Territory of the Carcross/Tagish First Nation. This is a transboundary water, with the Program Overview southern portion in British Columbia. The Lake Trout Monitoring Program uses the Summer Profundal Index Access and Use Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Bennett Lake is accessed via Carcross, with an accessible boat ramp. This lake is known for its This program surveys the two species by placing gill nets throughout high winds and as such, sees little recreational the lake, taking into account both location and depth. Over time, this pressure, however this is an important lake as type of sampling allows us to track population changes and evaluate the identified by the Carcross/Tagish First Nation. health of these species.

SR-20-02 27 Lake Trout Lake Whitefish

Overview Overview During the 2014 survey of Bennett Lake, a total of 128 lake During this survey, there were 39 lake whitefish sampled in trout were captured, ranging in size from 177 mm to 795 mm Bennett Lake. The captured lake whitefish ranged in size in fork length. Sampled lake trout had an average length of from 280 mm to 580 mm, with an average length of 424 462 mm and weight of 1,315 g. Age structures were mm and weight of 1, 034 g. Age structures were obtained obtained from 82 individuals. Ages ranged from 3 to 22. from six lake whitefish. Ages ranged from 5 to 20 years.

Population Estimate / Density Temperature and Oxygen The population of lake trout in Bennett Lake was estimated at 28,629 (estimate range: 13,855 – 43,870). This equates to a Temperature and dissolved oxygen profiles were taken density of 3.2 lake trout per hectare. within the main basin, Milhaven Bay, west arm and south arm. Measurements were taken to a depth of 60 m, which was the limit of our equipment. The main basin, west and

25 south arms, showed similar profiles, with a weak thermocline between 5 and 11 m. Milhaven bay was shallow and 20 exhibited a higher surface temperature, which gradually declined with depth. No thermocline was evident. Overall, 15 y

c Bennett Lake profiles illustrated suitable habitat throughout n e u

q the water body for lake trout and lake whitefish. e r 10 F t n e c r Main Basin Milhaven Bay e

P 5 Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 0 5 10 15 20 0 0

0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 10 00 2 50 7 2 7 2 7 2 7 00 50 2 7 2 7 10 6 6 6 6 300 3 350 3 400 4 450 4 500 5 550 5 7 72 7 77 800 8 850 8 900 9 950 9 1000 Fork Length (mm) 20 20

30 30 ) ) m m ( ( h

900 h t t p p e e D 40 D 800 40

700 ) 50 50

mm 600 ( h t

g 60 500 60 n Temperature e Temperature L k

r 400 Dissolved Oxygen Dissolved Oxygen o 70

F 70 300

200

100 West Arm South Arm Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 0 5 10 15 0 0 0 0 5 10 15 20 25 Age (year) 10 10

20 20

) 30 ) 30 m m ( ( h h t t p p e e D 40 D 40

50 50 For more information, please contact 60 60 Department of Environment Temperature Temperature Dissolved Oxygen Dissolved Oxygen Fish and Wildlife, Fisheries 70 70 [email protected] 867-667-5652

SR-20-02 Table of Contents

28 Fish and Wildlife Branch Fisheries Report

Braeburn Lake 2016 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters B Survey results from 2016 indicate Braeburn Lake has a small population of large-bodied lake trout when compared across Yukon lakes of similar SURFACE AREA ELEVATION size. Populations this size may not indicate collapse or depletion, 562 ha 695 m however they should be monitored to prevent overharvest.

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 50 m 14.3 m The 2016 survey results indicate a small population of lake whitefish. SURFACE TEMPS. REGULATIONS The harvest pressure on lake whitefish is unknown. However our survey 15.6OC Special management results suggest a conservative approach to harvest may be warranted, given the importance of this species as a lake trout food source. SAMPLING DATES NET SETS June 22-23, 2016 50 Recommendation Location The recommendation for future surveys would be to increase the number of net sets and biological samples for age analysis. This would Braeburn Lake is located approximately 103 help increase the accuracy of our population estimates and to detect km north of Whitehorse, near the North changes in abundance and population structure. The performance of an Klondike Highway, surrounded by a small Angler Harvest Survey on this lake would also assist in determining community. This lake lies within the Traditional recreational fishing pressures. Territories of the Ta’an Kwäch’än Council, Little Salmon/Carmacks First Nation, Champagne/ Aishihik First Nation and Kwanlin Dün First Nation. Program Overview The Lake Trout Monitoring Program uses the Summer Profundal Index Access and Use Netting (SPIN) method to provide information on lake trout and lake Braeburn Lake is accessed through a public whitefish abundance, growth, age and density. boat launch, near the north end of the lake, This program surveys the two species by placing gill nets throughout with multiple private residences along the east the lake, taking into account both location and depth. Over time, this and west shoreline. type of sampling allows us to track population changes and evaluate the health of these species. SR-20-02 29 Lake Trout Lake Whitefish

Overview Overview During the 2016 survey of Braeburn Lake a total of 18 lake A total of only seven lake whitefish were sampled, ranging in trout were sampled. They ranged in size (fork length) from size from 312 mm to 521 mm, with an average fork length of 258 mm to 712 mm. Their average length was 527 mm and 491 mm and an average weight of 1,811 g. Age structures their average weight was 1,978 g. Age structures were were obtained from 6 lake whitefish. Ages ranged from 4 to obtained from eight lake trout. Ages ranged from 6 to 20 26 years. years. 50 45 Population Estimate / Density 40 y c n

The population of lake trout in Braeburn Lake, as assessed e 35 u q e during the 2016 survey was estimated to be1,034 (estimate r 30 F t n range: 135 – 1,950). This equated to a density of 1.8 large- e 25 c r e bodied lake trout per hectare. Given the small sample size, P 20 there is little confidence in this estimate. 15 10 5 25 0 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 20 Fork Length (mm) y c n

e 15 u q e r F t n

e 10 Temperature and Oxygen c r e P

5 Temperature and dissolved oxygen profiles were taken on June 22, 2016. The temperature profile displayed a gradual 0 thermocline from 6 m to 15 m and a temperature range 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0

1 suitable for lake trout between 9 m and 40 m. Dissolved oxygen was relatively stable, decreased with depth and was Fork Length (mm) suitable for lake trout throughout the water column.

800 Temperature (C), Dissolved Oxygen (mg/L) 0.00 5.00 10.00 15.00 20.00 700 0.000

600 ) 5.000 mm ( 500 h t

g 10.000 n

e 400 L k r o F 300 15.000

200 ) 20.000 m ( h 100 t p e 25.000 D 0 0 5 10 15 20 25 30.000 Age (year)

35.000

40.000 For more information, please contact Temperature 45.000 Department of Environment Dissolved Oxygen Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

30 Fish and Wildlife Branch Fisheries Report

Caribou Lake 2011 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS Survey results indicated the lake is productive and has a large density of Yukon Headwaters A small-bodied lake trout. This finding agrees with historical Angler Harvest Surveys and previous netting surveys. The population of lake SURFACE AREA ELEVATION trout in Caribou Lake appears healthy. 51 ha 820 m

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 21 m 16.5 m There were no lake whitefish captured during this survey. Additional species captured during the survey included arctic grayling and round SURFACE TEMPS. REGULATIONS whitefish. 17.2OC Special management

SAMPLING DATES NET SETS Recommendation July 5-7, 12 ,2011 32 The recommendation from the 2011 survey was to replicate this survey in 2012 and to use this lake to determine the accuracy of SPIN methods. Location Caribou Lake is located approximately 50 km southeast of Whitehorse, east of Marsh Lake. Program Overview This lake is found within the Traditional Territories of the Carcross/Tagish and Kwanlin The Lake Trout Monitoring Program uses the Summer Profundal Index Dün First Nations. Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Access and Use This program surveys the two species by placing gill nets throughout Access to Caribou Lake is by an unmaintained the lake, taking into account both location and depth. Over time, this road from the Alaska Highway. There is no type of sampling allows us to track population changes and evaluate the boat launch at the lake. There is one residence health of these species. on the lake.

SR-20-02 31 Lake Trout Lake Whitefish

Overview Overview A total of 87 lake trout were captured during the 2011 No lake whitefish were captured in Caribou Lake during the survey, ranging from 280 mm to 460 mm in fork length. Age 2011 survey. structures were not obtained during the 2011 survey.

Population Estimate / Density Temperature and Oxygen The lake trout population was estimated at2,716 (estimate range: 2,238 – 3,237). This equates to a density of 53.2 lake Temperature and dissolved oxygen profile were taken in trout per hectare, which is the largest recorded density of all the north basin of Caribou Lake. The lake exhibited sampled Yukon lakes. stratification at 6.5 m. Dissolved oxygen levels were optimal (>7 mg/L) down to 13 m, and suitable between 13 and 15 m. 25%

20% Temp (C), Dissolved Oxygen (mg/L)

0 5 10 15 20 0 15% y c n e u q e r 10% F

t 5 n e c r e P

10 ) m 0% ( h 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 t

p Temp 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 e D Fork Length (mm) 15 Dissolved Oxygen

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

32 Fish and Wildlife Branch Fisheries Report

Caribou Lake 2012 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS Caribou Lake was found to have a healthy population of small- Yukon Headwaters A bodied lake trout in 2012. This survey showed no statistical SURFACE AREA ELEVATION difference in population or density for lake trout, when compared to the 2011 survey. This result helped to validate the effectiveness of 51 ha 820 m the SPIN method in estimating lake trout population size. MAXIMUM DEPTH AVERAGE DEPTH 21 m 16.5 m Lake Whitefish There were no lake whitefish captured during this survey. SURFACE TEMPS. REGULATIONS 16.9OC Special management Recommendation SAMPLING DATES NET SETS The recommendation from the 2012 survey is to continue using the June 25-27, 2012 30 SPIN methodology. Given our experimental results, in most instances, the number of nets should be increased to improve the Location precision of our population estimates. Caribou Lake is located approximately 50 km southeast of Whitehorse, east of the northern end of Marsh Lake. This lake is found within Program Overview the Traditional Territories of the Carcross/ Tagish and Kwanlin Dün First Nations. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Access and Use Access to Caribou Lake is by an unmaintained This program surveys the two species by placing gill nets road from the Alaska Highway. There is no throughout the lake, taking into account both location and depth. boat launch at the lake. There is one residence Over time, this type of sampling allows us to track population on the lake. changes and evaluate the health of these species.

SR-20-02 33 Lake Trout Lake Whitefish

Overview Overview A total of 83 lake trout were captured during the 2012 No lake whitefish were captured in Caribou lake during the survey. They ranged in size from 260 mm to 490 mm in fork 2012 survey. length. The sampled lake trout had an average length of 390 mm and average weight of 630 g. Age structures were obtained from 22 lake trout. Ages ranged from 7 to 24 years.

Population Estimate / Density Temperature and Oxygen The lake trout population in Caribou Lake was estimated at 2,851(estimate range: 2,360 – 3,381). This equates to a Temperature and dissolved oxygen profiles were taken in the density of 55.9 lake trout per hectare. This population and north basin of Caribou Lake on June 25, 2012. This location density estimate is similar to the 2011 survey (estimate was the deepest part of the lake. Temperatures and oxygen 2,716, density 53.2), with no significant difference between levels were within suitable levels for lake trout. We found a the two years. thermocline occurring between 3 m and 4 m with a sudden drop from 15oC to 12oC. Optimal dissolved oxygen levels 30 were found to a depth of 15 m.

20 Temperature (C), Dissolved Oxygen (mg/L) y c

n 0 5 10 15 20

e 2011 u

q 0 e 15 r 2012 F t n e c r e

P 10 5

0 10 ) m (

Fork Length (mm) h t p e D 15 Temperature

700 Dissolved Oxygen 600 20

500 ) mm

( 400 h t

g 25 n

e 300 L k r o

F 200

100

0 0 5 10 15 20 25 30 Age (year)

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

34 Fish and Wildlife Branch Fisheries Report

Chadburn Lake 2015 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Yukon Headwaters B Lake Trout Chadburn Lake has a large density of small-bodied lake trout when SURFACE AREA ELEVATION compared to most other Yukon lakes. However this density is slightly 144 ha 877 m lower when compared to other lakes of a similar size. The population appears healthy, however given our estimate of population size a MAXIMUM DEPTH AVERAGE DEPTH harvest strategy that is conservative may be warranted. 43 m 15 m

SURFACE TEMPS. REGULATIONS Lake Whitefish 15.8OC Special management There were no lake whitefish captured during this survey. Other sampled species included round whitefish. SAMPLING DATES NET SETS June 23-25, 2015 37 Recommendation The recommendation for future surveys is to increase the amount of net Location sets and collection of biological data for age analysis. This would Chadburn Lake is located within the city of improve our precision for population estimates and our ability to detect Whitehorse, in southern Yukon. This lake is changes. found within the Traditional Territories of the Kwanlin Dün First Nation and the Ta’an Kwäch’än Council. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Chadburn Lake is accessed via the Chadburn whitefish abundance, growth, age and density. Lake Road, in the Whitehorse subdivision of Riverdale. This is a popular recreational lake This program surveys the two species by placing gill nets throughout with an accessible dock. This lake is part of the lake, taking into account both location and depth. Over time, this Whitehorse’s Chadburn Lake Park. type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 35 Lake Trout Lake Whitefish

Overview Overview During the 2015 survey of Chadburn Lake, a total of 53 lake There were no lake whitefish captured during this survey. trout were captured, ranging from 260 mm to 580 mm in The only additional species captured was round whitefish, of fork length. The average length and weight of sampled fish which 139 were captured. This species had an average were 406 mm and 817 g. Age structures were obtained from length of 345 mm and an average weight of 410 g. Given 27 lake trout. Ages ranged from 5 to 36 years. the number of round whitefish sampled, this species may serve as the principle prey species for lake trout. Population Estimate / Density The population estimate was2,941 (estimate range: 2,014 – 3,916). This equates to a density of 20.4 lake trout per Temperature and Oxygen hectare. To date, this is one of the largest densities assessed within Yukon lakes. Temperature and dissolved oxygen profiles were taken on June 25. The temperature profile shows a strong thermocline between 5 m and 8 m, with temperatures unsuitable for lake 35 trout within the first 5 m. Dissolved oxygen was found to be

30 within a acceptible level throughout the water column.

y 20 c n e

u Temperature (C), Dissolved Oxygen (mg/L) q

e 15 0 5 10 15 20 r F 0 t n e

c 10 r e

P 5 5

10 0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 2 7 2 7 00 50 2 7 2 7 6 6 6 6 300 3 350 3 400 4 450 4 500 5 550 5 7 72 7 77 800 8 850 8 900 9 950 9

1000 15 Fork Length (mm)

20 ) m ( h

t 25 p

e Temperature D Dissolved Oxygen 30 800

700 35

600

) 40 mm

( 500 h t

g 45 n

e 400 L k r o

F 50 300

200

100

0 0 5 10 15 20 25 30 35 40

Age (year)

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

36 Fish and Wildlife Branch Fisheries Report

Ethel Lake 2011 Lake Trout Monitoring Program

Overall Status Lake Information Lake Trout The density of lake trout in Ethel Lake was lower than expected, in WATERSHED LAKE CLASS comparison to similar sized Yukon lakes. This may be related to Upper Stewart D recreational harvest pressures, as well as a former commercial fishery, SURFACE AREA ELEVATION which closed in 1967. 4610 ha 760 m Lake Whitefish MAXIMUM DEPTH AVERAGE DEPTH Only 15 lake whitefish were captured during the 2011 survey. This 62 m 31 m may indicate small lake whitefish numbers in Ethel Lake. Additional species sampled included: arctic grayling and round whitefish. SURFACE TEMPS. REGULATIONS 14.7OC Conservation waters Recommendation SAMPLING DATES NET SETS The number of net sets used during the survey should be increased July 18-21, 2011 90 as well as the collection and analysis of age structures. This will help increase the precision of our population estimates and understanding Location of the population structure. Ethel Lake is located approximately 20 km east of Stewart Crossing. Ethel Lake is in the Traditional Territory of the First Nation of Na- Program Overview Cho Nyäk Dun. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and Access and Use lake whitefish abundance, growth, age and density. A seasonal access road is located approximately 10 km south of Stewart This program surveys the two species by placing gill nets throughout Crossing off the Klondike Highway. There is a the lake, taking into account both location and depth. Over time, this government campground and a boat launch at type of sampling allows us to track population changes and evaluate the western end of the lake, along with several the health of these species. private residences.

SR-20-02 37 Lake Trout Lake Whitefish

Overview Overview A total of 30 lake trout were captured during the 2011 A total of 15 lake whitefish were captured during the 2011 survey, ranging from 290 mm to 910 mm in fork length. survey. As such, we did not determine population numbers. Sampled fish had an average length of 573 mm and weight Given the small sample size, we have concerns the of 3,333 g. Age structures were not obtained during the population may be low, or there is limited habitat for lake 2011 survey. whitefish.

Population Estimate / Density Temperature and Oxygen The lake trout population was estimated at9,102 (estimate range: 1,902 – 16,450). This equates to a density of 2.0 lake The profiles of oxygen and temperature indicated water trout per hectae. However given the small sample size, our conditions were suitable for lake trout. However, optimal confidence in this estimate is weak. habitat ranged from 8 – 38 m. There may be less suitable habitat at the surface due to higher temperatures.

0.12

0.1 Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 20 0 0.08 y c n

e 5 u q e

r 0.06 F t

n 10 e c r e

P 0.04 15

0.02 Temperature 20 )

m Dissolved 0 (

h Oxygen 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

t 25 6 6 0 4 8 6 p 3 5 6 6 6 7 28 32 40 44 48 52 72 80 84 88 92 e D Fork Length (mm) 30

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

38 Fish and Wildlife Branch Fisheries Report

Fish Lake 2010 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS Yukon Headwaters C The results from this survey indicated Fish Lake has a large population of small-body lake trout. This population appears healthy. Lake trout SURFACE AREA ELEVATION appear to be the top predators in this moderately productive lake. 1386 ha 1123 m Lake Whitefish MAXIMUM DEPTH AVERAGE DEPTH 37 m 16.5 m Fish Lake does not contain lake whitefish. The additional fish species sampled in this lake included arctic grayling and a small population of SURFACE TEMPS. REGULATIONS round whitefish. 14.3OC Special Management

SAMPLING DATES NET SETS Recommendation August 19-20, 2010 29 The recommendation from the 2010 survey is to revisit and sample this lake in 2012 to compare results. Location Fish Lake is located approximately 15 km Program Overview southwest of Whitehorse at the end of the Fish Lake Road. The lake is found within the The Lake Trout Monitoring Program uses the Summer Profundal Index Traditional Territory of the Kwanlin Dün First Netting (SPIN) method to provide information on lake trout and lake Nation. whitefish abundance, growth, age and density. This program surveys the two species by placing gill nets throughout Access and Use the lake, taking into account both location and depth. Over time, this Fish Lake is accessed by Fish Lake Road, type of sampling allows us to track population changes and evaluate the along the Alaska Highway near Whitehorse. health of these species. There is an accessible boat launch at the lake and a private campground nearby.

SR-20-02 39 Lake Trout Lake Whitefish

Overview Overview Fifty lake trout were captured during the survey, ranging in During the survey of Fish Lake, no lake whitefish were size from 265 mm to 865 mm in fork length. The average captured. length was 426 mm, while the average weight was 926 g. During the 2010 survey, no lake trout were sampled for age structures. As such, we are unable to present length/age relationships. Temperature and Oxygen Population Estimate / Density Temperature and oxygen profiles were not assessed during The lake trout population was estimated at approximately the 2010 survey as this specialized equipment was not 41, 787 (ranging between 31,770 – 52, 486). This available. corresponds to an estimate of 30.1 lake trout per hectare.

25%

20% y

c 15% n e u q e r F

t 10% n e c r e P

0% 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 7 9 1 3 5 7 9 1 3 5 7 9 1 3 5 7 9 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5 Fork Length (mm)

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

40 Fish and Wildlife Branch Fisheries Report

Fish Lake 2012 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS The small-bodied lake trout population in Fish Lake remains healthy. Yukon Headwaters C Fish Lake continues to have a high density of lake trout. SURFACE AREA ELEVATION Lake Whitefish 1386 ha 1123 m During the 2012 survey, no lake whitefish were captured. MAXIMUM DEPTH AVERAGE DEPTH 37 m 16.5 m Recommendation

SURFACE TEMPS. REGULATIONS The recommendation from the 2012 survey is to maintain consistent 7.16OC Special Management survey timing for repeated SPIN sampling. This will reduce variations in fish numbers due to seasonal differnces. Additionally, for Yukon a SAMPLING DATES NET SETS standardized sampling period should be adopted for all SPIN surveys. It July 5-12, 2012 29 is also recommended to sample for temperature and dissolved oxygen content. Location Fish Lake is located approximately 15 km southwest of Whitehorse at the end of the Program Overview Fish Lake Road. The lake is found within the Traditional Territory of the Kwanlin Dün First The Lake Trout Monitoring Program uses the Summer Profundal Index Nation. Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Access and Use This program surveys the two species by placing gill nets throughout Fish Lake is accessed by Fish Lake Road, the lake, taking into account both location and depth. Over time, this along the Alaska Highway near Whitehorse, type of sampling allows us to track population changes and evaluate the with a boat launch at the lake and a private health of these species. campground nearby.

SR-20-02 41 Lake Trout Lake Whitefish

Overview Overview A total of 122 lake trout were captured during the 2012 During the survey of Fish Lake, no lake whitefish were survey, ranging from 225 mm to 640 mm in fork length. captured. Sampled fish had an average length of 390 mm and average weight of 732 g. Age structures were obtained from 18 lake trout during the 2012 survey, ages ranged from 7 to 27 years old.

Population Estimate / Density Temperature and Oxygen The lake trout population within Fish Lake was estimated to be75,562 (estimate range: 62,403 – 89,955). This equates Temperature and dissolved oxygen profiles were taken near to a density of 54.4 lake trout per hectare. This population the middle of Fish Lake, on July 5, 2012. We did not record estimate was larger than the 2010 estimate. This may be temperature stratification and there was an odd shift recorded due to variation in survey dates. This survey was conducted for dissolved oxygen levels between 9 and 17 m. There is an during July, as opposed to the August survey in 2010. This uncertainty associated with instrument error. Future surveys shift in sampling dates may have created changes in lake should resample to ensure accuracy. trout distributions associated with habitat availability. Their preferred temperatures may have been confined to deeper waters. As such, it is difficult to compare these two surveys. Temperature (C), Dissolved Oxygen (mg/L)

25% 0 5 10 15 20 0

20%

15% 2010

y 2012 c n e

u 10 q e r 10% F t n e c r e P 15 5% ) m 0% ( 20 h 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 t 1 3 5 5 7 9 1 3 5 7 9 1 3 5 7 9 1 3 5 7 9 p 6 6 6 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5 e

Fork Length (mm) D 25

700 Temperature

600 30 Dissolved

) 500 Oxygen mm

( 35 h t 400 g n e L k

r 300 o 40 F

200

100

0 0 5 10 15 20 25 30

Age (yr)

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

42 Fish and Wildlife Branch Fisheries Report

Fox Lake 2013 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS Yukon Headwaters C Fox Lake has a population of lake trout that are large-bodied. When compared to lakes of similar size, this population appears smaller. This SURFACE AREA ELEVATION may be due to the lakes popularity as a recreational angling destination. 1602 ha 957 m Lake Whitefish MAXIMUM DEPTH AVERAGE DEPTH 47 m 28.6 m The lake whitefish population in Fox Lake was found to be healthy with a large relative density, as well as a large average size, when compared SURFACE TEMPS. REGULATIONS to other Yukon lakes. This healthy population may be an indication of a 14.54OC Special Management decreased lake trout (predator) population size.

SAMPLING DATES NET SETS Recommendation July 3-5,10, 2013 81 The recommendation from the 2013 survey is to place this lake into Special Management regulations, wherein we will limit harvest pressure. Location This may assist with this populations natural recovery. An increase in Fox Lake is located approximately 60 km north net sets and collection of biological data for age analysis is of Whitehorse and is found within the Ta’an recommended to increase confidence in our population estimates and Kwäch’än Council and Kwanlin Dün First provide more information on population structure. Nation Traditional Territories.

Access and Use Program Overview Access to Fox Lake is along the North The Lake Trout Monitoring Program uses the Summer Profundal Index Klondike Highway. There is a popular Netting (SPIN) method to provide information on lake trout and lake campground on the eastern shore, with an whitefish abundance, growth, age and density. accessible boat launch. There is a second boat launch near the southern end, along with This program surveys the two species by placing gill nets throughout several residences along the eastern shoreline. the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 43 Lake Trout Lake Whitefish

Overview Overview During the 2013 survey, a total of 73 lake trout were A total of 261 lake whitefish were sampled during the captured, ranging in length from 232 mm to 730 mm. The survey, ranging in size from 173 mm to 565 mm in fork average length and weight of sampled fish were 448 mm length. The average length was 469 mm and the average and 1,114 g. Age structures were obtained from 15 lake weight was 1,328g. Age structures were analyzed from 93 trout. Ages ranged from 7 to 24 years. lake whitefish. Ages ranged from 4 to 34 years. This population appears healthy.

Population Estimate / Density 40

The lake trout population in Fox Lake was estimated at 35

5,397 (estimate range: 2,763 – 8,120). This equates to a 30 y c density of 3.4 lake trout per hectare. There is some evidence n 25 e u q e this population may be depleted, when compared to similar r

F 20 t n sized Yukon Lakes. e c

r 15 e P 10

5 35 0 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 00 50 2 7 2 7 2 7 00 6 6 6 6 30 1 150 1 2 22 2 27 300 3 350 3 400 4 450 4 500 5 550 5 7

Fork Length (mm) 25 y c n e

u 20 q e r

F Temperature and Oxygen t

n 15 e c r e P 10 Temperature and dissolved oxygen profiles were taken from the middle of the lake on July 3, 2013. The lake was stratified 5 with a defined thermocline between 10 m and 11 m. 0 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 Temperatures were suitable throughout the water column. 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 Dissolved oxygen levels were optimal between 7 m and 42 Fork Length (mm) m.

700 Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 20 0.0 600

5.0

) 500 mm (

h 10.0 t 400 g n e L

k 15.0 r 300 o F

200 20.0

) Temperature m ( Dissolved Oxygen h

100 t 25.0 p e D

0 30.0 0 5 10 15 20 25 30

Age (year) 35.0

40.0

45.0 For more information, please contact 50.0 Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

44 Fish and Wildlife Branch Fisheries Report

Frenchman Lake 2012 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters C The lake trout population in Frenchman Lake appears to be smaller in density than similar sized lakes in Yukon. This large-bodied population SURFACE AREA ELEVATION may be showing signs of depletion due to higher angler activity and 1441 ha 575 m competition for prey with northern pike.

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 65 m 14.6 m The lake whitefish population appears healthy, however it was observed SURFACE TEMPS. REGULATIONS that the average fork length of this population is slightly smaller than 14.3OC Special Management observed in other Yukon lakes.

SAMPLING DATES NET SETS Recommendation June 18-19, 2012 58 We recommend an increase in the number of net sets used when this Location lake is resampled in the future. This will aid in detecting population Frenchman Lake is located approximately 26 changes and increase the precision of our estimates. It is also km east of the Village of Carmacks within the recommended that catch and possession limits are reduced, to allow Traditional Territory of the Little Salmon/ this population to recover. Carmacks First Nation.

Access and Use Program Overview Access to Frenchman Lake is via the seasonal The Lake Trout Monitoring Program uses the Summer Profundal Index Frenchman Lake Road which turns north off of Netting (SPIN) method to provide information on lake trout and lake the Robert Campbell Highway 39 km east of whitefish abundance, growth, age and density. the Village of Carmacks and connects with the Klondike Highway at km 384, just north of This program surveys the two species by placing gill nets throughout Tatchun Creek. There are two government the lake, taking into account both location and depth. Over time, this campgrounds along Frenchman Lake with type of sampling allows us to track population changes and evaluate the accessible and popular boat launches. health of these species.

SR-20-02 45 Lake Trout Lake Whitefish

Overview Overview A total of 15 lake trout were captured during the 2012 A total of 158 lake whitefish were captured during this survey, ranging in size from 267 mm to 870 mm. Sampled survey. They ranged in fork length from 202 mm to 387 mm. fish averaged 533 mm in length and 870 g in weight. Age Sampled fish had an averalge length of 300 mm and weight structures were obtained from 4 lake trout. Ages ranged of 392 g. This average length is smaller than average lengths from 7 to 15 years. reported for other assessed Yukon lakes (avg: 413 mm). Age structures were analyzed from 33 lake whitefish. Ages Population Estimate / Density ranged from 4 to 17 years. The lake trout population estimate for Frenchman Lake was 45 2,874 (estimate range: 624 – 5,172). This equated to a density of 2.0 lake trout per hectare. This is a lower estimate 40 35

than other similarily sized lakes surveyed in Yukon (prior to y c

n 30 e

2012). u q

e 25 r F t n

e 20 c r e

16 P 15

14 10 5 12 y c 0 n e

u 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475 500 525 550 575 600 625 650 675 700

q 10 e r F t n 8 Fork Length (mm) e c r e P 6 Temperature and Oxygen 4

2 Temperature and dissolved oxygen profiles were taken in both of the lake’s basins. Basins were sharply stratified, with 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 suitable lake trout temperatures beginning at 7 m and 0 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0 1 continuing to lake bottom. Dissolved oxygen levels were Fork Length (mm) optimal over the depth range of both profiles.

700 Central Basin North Basin

600 Tempterature (C), Dissolved Oxygen (mg/L) Tempterature (C), Dissolved Oxygen (mg/L) 0 5 10 15 0 5 10 15 20 ) 500 0 0 mm ( h t g 400 n e 10 L 10 k r o

F 300

20 20 200 Temperature

100 30

) 30 Dissolved ) m m ( (

h Oxygen h t t p p e 0 e D 0 2 4 6 8 10 12 14 16 40 D 40

Age (yr)

50 50

For more information, please contact 60 60 Department of Environment 70 Fish and Wildlife, Fisheries 70 [email protected] 867-667-5652

SR-20-02 Table of Contents

46 Fish and Wildlife Branch Fisheries Report

Kathleen Lakes 2019 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS The lake trout population in the two basins of the Kathleen Lakes were Stewart B small in number, when compared to lakes of similar size. However, due SURFACE AREA ELEVATION to high temperatures and low oxygen levels lake trout habitat is limited 1389(U), 753 (L) ha 723 m in the east basin and this may be contributing to the smaller population size. MAXIMUM DEPTH AVERAGE DEPTH 59(U), 43(L) m 4.4(U), 3.5(L) m Lake Whitefish SURFACE TEMPS. REGULATIONS There were no lake whitefish captured within this system. 17.3OC General waters Recommendation SAMPLING DATES NET SETS July 07-09, 2019 31 The recommendation for future surveys of the Kathleen Lakes is to continue monitoring the depth profiles and to determine recreational Location harvest pressures. If this lake is repeated, an effort to increase net sets and determine age cohorts will assist in determining population size and The Kathleen Lakes are located 109 km health. northeast of the community of Mayo. These lakes are found within the Traditional Territory of the First Nation of Na-Cho Nyäk Dun. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index The Kathleen Lakes are accessible by fly-in Netting (SPIN) method to provide information on lake trout and lake only, with an established outfitting lodge on whitefish abundance, growth, age and density. the west basin. There is no road access, nor This program surveys the two species by placing gill nets throughout additional private residences on these lakes. the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 47 Lake Trout Lake Whitefish

Overview Overview During the 2019 survey of the east and west basins of the No lake whitefish were captured during this survey. Kathleen Lake, there were only 6 lake trout captured. The sampled lake trout ranged in fork length from 522 mm to 601 mm. They had an average length of 565 mm and an average weight of 2158 g. Age structures were not obtained from these fish. Temperature and Oxygen Temperature and dissolved oxygen profiles were taken in Population Estimate / Density both the west and east basin on July 8 and 9 , respectively. The lake trout population estimate for Kathleen Lakes was The temperature profiles indicated a sharp thermocline estimated at593 (estimate range: 1 to 1,218). This resulted between 4 m and 7 m, with temperatures decreasing from in a density of 1.5 lake trout per hectare. However due to the 16oCto5oC within the thermocline. Temperatures gradually small sample size there is little confidence in this estimate. declined below this, through the rest of the water column. Dissolved oxygen profiles in both basins displayed a sharp decrease from 5 m through 10 m. In the east basin, below 9 35.0 m, oxygen levels were unsuitable to support lake trout. 30.0 Suitable lake trout habitat in the west basin was found from 5

25.0 m to the lake’s bottom. y c n e

u 20.0 q e r F t

n 15.0

e East Basin West Basin c r e

P 10.0 Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 20 0 5 10 15 20 5.0 0 0

0.0 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 5 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 Fork Length (mm) 10 10

15 15 ) ) 20 20 m m ( ( Temperature Temperature h h t t p p e e D D 25 Dissolved 25 Dissolved Oxygen Oxygen

30 30

35 35

40 40

45 45

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

48 Fish and Wildlife Branch Fisheries Report

Kluane Lake 2013 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Alsek F Kluane Lake has a high density and healthy population of large-bodied lake trout. The lake trout population in Kluane receives minimal angling SURFACE AREA ELEVATION pressure, relative to other Yukon lakes, due to its remote location, wind 40,821 ha 781 m and size.

MAXIMUM DEPTH AVERAGE DEPTH 91 m 31 m Lake Whitefish The lake whitefish population in Kluane Lake was found to be healthy, SURFACE TEMPS. REGULATIONS with a higher relative density when compared to similar sized lakes in 9.4OC Conservation waters Yukon. SAMPLING DATES NET SETS August 6-11, 2013 129 Recommendation The 2013 survey of Kluane Lake was conducted prior to the natural diversion of the Kaskawalsh Glacier away from Slims River, historically a Location major input to this lake. As such, the data from this survey serves as Kluane Lake is located approximately 60 km baseline for lake trout and lake whitefish population levels. It is northwest of Haines Junction and borders recommended that Kluane lake is reassessed based on these prior Kluane National Park and Reserve. Kluane levels. A slight increase in the number of net sets, should also occur to Lake is within the White River First Nation and increase our ability to determine population change. It is also Kluane First Nation Traditional Territories. recommended that habitat mapping of lake trout spawning locations is conducted along with analysis of ages. Access and Use Kluane Lake is accessed along the Alaska Highway, with a government campground at Program Overview Congdon Creek, as well as multiple private campgrounds and residences along the lake. The Lake Trout Monitoring Program uses the Summer Profundal Index Boat ramps are available in several locations, Netting (SPIN) method to provide information on lake trout and lake however not all of them are in useable whitefish abundance, growth, age and density. condition. This program surveys the two species by placing gill nets throughout the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the SR-20-02 health of these species. 49 Lake Trout Lake Whitefish

Overview Overview During the 2013 survey, a total of 168 lake trout were A total of 471 lake whitefish were captured during this captured, ranging in fork length from 240 mm to 950 mm. survey. These sampled whitefish ranged in size from 217 The sampled fish had an average length of 552 mm and mm to 545 mm in fork length, with an average length of 376 average weight of 2,348 g. Age structures were obtained mm and weight of 792 g. Age structures were analyzed from from 51 lake trout. Ages ranged from 4 to 38 years. 202 lake whitefish. Ages ranged from 3 to 37 years.

Population Estimate / Density 25 The population of lake trout within Kluane Lake was 20 estimated at168,712 (estimate range: 99,487 – 240,691). y c n

This equates to a density of 4.3 lake trout per hectare, which e 15 u q e r

can be considered a moderate to high density for this large- F t n

e 10 bodied population. c r e P

14 0 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 00 50 2 7 2 7 2 7 00 6 6 6 6 12 1 150 1 2 22 2 27 300 3 350 3 400 4 450 4 500 5 550 5 7

Fork Length (mm) y

c 10 n e u q e

r 8 F t

n Temperature and Oxygen e

c 6 r e P 4 Temperature and dissolved oxygen profiles were taken in two locations, the main basin and Talbot Arm. 2 Temperatures and dissolved oxygen were optimal in the 0 5 0 5 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 5 0 5 0 5 0 5 0 0

0 main basin from the surface to 60 m (maximum equipment 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0 1 depth). In Talbot Arm, temperatures steadily declined, with Fork Length (mm) dissolved oxygen relatively constant through the water 800 column. 700

) 600 mm ( 500 Talbot Arm h Main Basin t g n

e 400 Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) L

k 0 5 10 15 0 5 10 15 r

o 0 0

F 300

200 10 10 100

0 0 5 10 15 20 25 30 35 40 20 20

Age (year) )

) 30 30 m m ( ( h h t t p p e e D 40 D 40

50 50 For more information, please contact 60 60 Department of Environment Temperature Dissolved Oxygen Fish and Wildlife, Fisheries 70 70 [email protected] 867-667-5652

SR-20-02 Table of Contents

50 Fish and Wildlife Branch Fisheries Report

Kusawa Lake 2014 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Yukon Headwaters E Lake Trout SURFACE AREA ELEVATION In accordance with our sampling results the lake trout population in Kusawa Lake, appears healthy. The population appears to be of a 14,018 ha 671 m slightly smaller physical size than can be found in similar sized lakes.

MAXIMUM DEPTH AVERAGE DEPTH 140 m 54 m Lake Whitefish The population of lake whitefish in Kusawa Lake appears to be smaller SURFACE TEMPS. REGULATIONS than expected for a lake of it’s size and productivity. However detailed O 12.2 C Conservation waters baseline information on this population is not available. SAMPLING DATES NET SETS July 2,3,7-10, 2014 158 Recommendation We achieved acceptable precision in our population estimate, therefore the recommendation for future surveys is to repeat the number of net Location sets performed in 2014. The results of this SPIN survey should taken under consideration when examining the results of the 2014 Angler Kusawa Lake is located in southern Yukon and Harvest Survey. In combination it will help us better understand the forms the basis of Kusawa Territorial Park. influences of recreational angling on the resource. This lake is within the Traditional Territories of the Carcross/Tagish First Nation and the Champagne/Aishihik First Nation. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Kusawa Lake is accessed via the Kusawa Lake Netting (SPIN) method to provide information on lake trout and lake Road, from the Alaska Highway. There is a whitefish abundance, growth, age and density. popular government campground at the lake, This program surveys the two species by placing gill nets throughout with an established boat ramp. This is a the lake, taking into account both location and depth. Over time, this popular recreational angling site for Yukon type of sampling allows us to track population changes and evaluate the residents. health of these species.

SR-20-02 51 Lake Trout Lake Whitefish

Overview Overview During the 2014 survey of Kusawa Lake, a total of 213 lake During this survey, there were 37 lake whitefish sampled. trout were sampled. They ranged from 174 mm to 875 mm The lake whitefish ranged from 325 mm to 450 mm. These in fork length. The sampled fish had an average length of sampled fish had an average length of 383 mm and an 443 mm and an average weight of 1,174 g. Age structures average weight of 730 g. Age structures were obtained from were obtained from 80 individuals,. Ages ranged from 3 to eight lake whitefish. Ages ranged from 5 to 24 years. The 28 years. catch rate for lake whitefish was less than we would expect for a lake of similar size and productivity.

Population Estimate / Density 50 The population of lake trout within Kusawa Lake during the 45 40 y

2014 survey was estimated at 78,045 (estimate range: c n 35 e u

51,860 – 105,506). This equates to a density of 5.6 lake q

e 30 r F

t 25 trout per hectare. This density indicates a healthy population n e c r of large-bodied lake trout. e 20 P 15 10

18 5 0 0 5 0 5 16 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 14 Fork Length (mm) 12 y c

n 10 e u q e

r 8 F Temperature and Oxygen t n

e 6 c r e P 4 Temperature and dissolved oxygen profiles were taken at

2 three locations in Kusawa Lake; a northern profile, a central

0 profile, and a southern profile. The north and central profiles 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 exhibited relative stablility in the water column, with slightly 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 warmer surface water. The south profile, in a shallower Fork Length (mm) section of the lake, indicated a stratified water column, with o o 1000 a thermocline between 9 C and 12 C. All profiles displayed

900 optimal dissolved oxygen levels.

800

700 North profile Central profile South profile

Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L)

) 600 0 5 10 15 0 5 10 15 0 5 10 15 0 0 0 mm

( 500 h t

g 10 10 10 n 400 e L k

r 300

o 20 20 20 F 200 ) ) ) 30 30 30 m m m ( ( 100 ( h h h t t t p p p e e e D D 0 D 40 40 40 0 5 10 15 20 25 30 Age (year) 50 50 50

60 60 60 Temperature Temperature Temperature Dissolved Oxygen 70 70 Dissolved Oxygen 70 Dissolved Oxygen For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

52 Fish and Wildlife Branch Fisheries Report

Ladue Lake 2017 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Stewart B Survey results from 2017 indicated the lake trout population in Ladue SURFACE AREA ELEVATION Lake appears to be low to moderate in abundance when compared to lakes of similar surface area. However this lake is small and relatively 253 ha 717 m shallow, therefore the lake may only be capable of supporting a small MAXIMUM DEPTH AVERAGE DEPTH population of lake trout, based on habitat availability. 48 m N/A Lake Whitefish SURFACE TEMPS. REGULATIONS 16.89OC Special Management The population of lake whitefish in Ladue Lakes seems healthy. A wide age demographic was sampled, suggesting the population is stable. SAMPLING DATES NET SETS June 26-28, 2017 32 Recommendation To increase our confidence in population estimates the recommendation Location for future surveys of Ladue Lake is to increase net sets. Also, lake trout Ladue Lake is located approximately 15 km habitat availability should be determined and increased age analysis. north of Keno City. Ladue Lake is found within Subsequent to improved access, an Angler Harvest Survey should also the Traditional Territory of the First Nation of be performed. Na-Cho Nyäk Dun.

Access and Use Program Overview Ladue Lake is accessed by a 4x4 trail, off the The Lake Trout Monitoring Program uses the Summer Profundal Index Mayo Elsa Road. There are no government Netting (SPIN) method to provide information on lake trout and lake campground and no accessible boat launches whitefish abundance, growth, age and density. at the lake. This program surveys the two species by placing gill nets throughout the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 53 Lake Trout Lake Whitefish

Overview Overview During the 2017 survey of Ladue Lake, a total of 33 lake During the 2017 survey, a total of 28 lake whitefish were trout were sampled. These large-bodied lake trout ranged in sampled. The size of these fish ranged from 265 mm to 528 fork length from 317 mm to 698 mm. The average length of mm. Sampled fish had an average fork length of 446 mm sampled fish was 561 mm with an average weight of 1,866 and an average weight of 1,224 g. Age structures were g. Age structures were only obtained from 10 lake trout. taken from 18 lake whitefish. Ages ranged from 6 to 30 Ages ranged from 11 to 31 years. years.

Population Estimate / Density 35% The population estimate for lake trout was789 (estimate 30% range: 377 to 1,215). This resulted in a density of 3.1 lake trout per hectare. 25% y c n e

30% u 20% q e r F t n

e 15% c 25% r e P

10%

20% y c

n 5% e u q e r

F 15%

t 0% n 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 e 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 c 6 6 6 6 25 27 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 r 1 e

P 10% Fork Lenth (mm) Temperature and Oxygen 5% Temperature and dissolved oxygen profiles were obtained on 0% 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 June 27th. The temperature profile displayed a sharp 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 25 27 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 thermocline from 3 m to 7 m, followed by a gradual decline Fork Lenth (mm) through the water column. Dissolved oxygen displayed a slight increase from 4 m to 7 m, followed by a gradual decline. 700 Overall, optimum habitat existed between 6 m to the lake’s

600 bottom.

500 Temperature (C), Dissolved Oxygen (mg/L) 0.00 5.00 10.00 15.00 20.00

) 0 m ( 400 h t n e L 5 k 300 r o F

200 10

100 Temperature

) 15 m ( Dissolved h 0 t Oxygen p

0 5 10 15 20 25 30 35 e D 20 Age (year)

30 For more information, please contact 35 Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

54 Fish and Wildlife Branch Fisheries Report

Lake Laberge 2016 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters F The 2016 survey results for Lake Laberge indicate a moderate to low SURFACE AREA ELEVATION density of lake trout, when compared to lakes of similar size. Survey 20,099 ha 628 m results also indicated a younger than expected lake trout population, which may sugggest overharvest. MAXIMUM DEPTH AVERAGE DEPTH 146 m 54 m Lake Whitefish SURFACE TEMPS. REGULATIONS The 2016 Lake Laberge survey indicated a moderate and healthy 14.2OC Conservation waters population of lake whitefish.

SAMPLING DATES NET SETS Recommendation July 27 - Aug 1, 2016 141 The recommendation for future surveys is to potentiallhy increase the Location number net sets during sampling. This would help increase the precision of our population estimate. An increase in the number of collected age Lake Laberge is located approximately 47 km structures to analyze is also recommended. Lakes of this size category north of Whitehorse, on the North Klondike are difficult to accurately assess. Highway. This lake is found within the Traditional Territories of the Ta’an Kwäch’än Council and Kwanlin Dün First Nation. This lake is part of the Yukon River. Program Overview The Lake Trout Monitoring Program uses the Summer Profundal Index Access and Use Netting (SPIN) method to provide information on lake trout and lake Lake Laberge is accessed through a public whitefish abundance, growth, age and density. boat launch, which is available at a This program surveys the two species by placing gill nets throughout government campground. There are several the lake, taking into account both location and depth. Over time, this private residences along the lake shore. type of sampling allows us to track population changes and evaluate the Historically, lake trout in this lake were health of these species. depleted by commercial fishing in the early 1900s.

SR-20-02 55 Lake Trout Lake Whitefish

Overview Overview During the 2016 survey of Lake Laberge a total of 109 lake A total of 100 lake whitefish were captured during the 2016. trout were sampled, ranging in size (fork length) from 310 The size of these fish ranged from 215 mm to 550 mm in mm to 716 mm. The sampled fish had an average length of length, with an average fork length of 339 mm and an 485 mm and an average weight of 1,737 g. Age structures average weight of 520 g. Age structures were obtained from were obtained from 43 lake trout. Ages ranged form 4 to 22 53 lake whitefish. Ages ranged from 5 to 16 years. years. 25 Population Estimate / Density 20 y c

The lake trout population estimate was51,121 (estimate n e u q e range: 19,475 – 83,602). This equates to a density of 2.6 r 15 F t large-bodied lake trout per hectare. Given the range of our n e c r e population estimate, our confidence in this number is weak. P 10

20 5 18 16 0 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 y 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 c n 6 6 6 6 14 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 e u q

e 12 Fork Length (mm) r F t

n 10 e c r

e 8 P 6 4 Temperature and Oxygen 2 Temperature and dissolved oxygen profiles were taken on 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0

0 July 22, 2016. The temperature profile displayed a gradual 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0 1 decline from the surface to 12 m, followed by a sharp Fork Length (mm) thermocline to 18 m. Optimal temperatures for lake trout occurred between 14 m and 57 m. Dissolved oxygen remained stable and optimal throughout the water column.

800

700 Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 20 600 0 ) mm ( 500 Temperature h t g n Dissolved Oxygen e 400 L 10 k r o F 300

200 20

100 )

0 m (

0 5 10 15 20 25 h

t 30 p Age (year) e D

50 For more information, please contact

Department of Environment 60 Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

56 Fish and Wildlife Branch Fisheries Report

Lewes Lake 2010 Lake Trout Monitoring Program

Lake Information Overall Status WATERSHED LAKE CLASS Yukon Headwaters B Lake Trout

SURFACE AREA ELEVATION Two surveys of Lewes Lake were conducted in the summer of 2010. The two surveys were used in an experiment to test the 728 m 131 ha efficacy of the SPIN methodology. The combined results indicated MAXIMUM DEPTH AVERAGE DEPTH that Lewes Lake has a high density of small-bodied lake trout. This population appears healthy based on this survey. 40 m 17 m

SURFACE TEMPS. REGULATIONS Lake Whitefish O General Waters 12.2 C Lewes Lake does not contain lake whitefish. The additional fish SAMPLING DATES NET SETS species sampled included arctic grayling and round whitefish. June 26-27, 2010 24 per survey Recommendation Augst 16-17, 2010 This lake was used as an experimental waterbody to test the efficacy of the Summer Profundal Index Netting program (SPIN) for Location Yukon. The recommendation from the 2010 survey is to perform Lewes Lake is located near the South Klondike future surveys in June or July, when water temperatures are cooler, Highway between Whitehorse and Carcross in resulting in more available habitat. the Yukon River watershed. Lewes Lake is in the Traditional Territories of the Carcross/ Tagish and Kwanlin Dün First Nations. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Lewes Lake is accessed by Lewes Lake Road, Index Netting (SPIN) method to provide information on lake trout off the South Klondike Highway. There are a and lake whitefish abundance, growth, age and density. number of permanent residences along the This program surveys the two species by placing gill nets road, with makeshift campsites near the lake. throughout the lake, taking into account both location and depth. There is no boat ramp available at the lake. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 57 Lake Trout Lake Whitefish

Overview Overview Eighty eight lake trout were captured during the two During the two surveys of Lewes Lake, no lake whitefish surveys. They avearaged 358 mm in length (as measured to were captured. the fork) and 533 g in weight. Age structures were taken from 31 lake trout. Ages ranged from 5 to 27 years.

Population Estimate / Density Temperature and Oxygen The estimated population of lake trout was6,369 (ranging Temperature profiles for June and August show that the between 5,202 – 7,639). Density estimated from the June lake was strongly stratified during both months. The survey was 48.6 lake trout per hectare and was 30.5 lake thermocline (zone of steep temperature decline) was trout per hectare from the August survey. The difference in located at a shallower depth in June (8.5 -10.5 m) when density estimates likely resulted from differences in compared to August (10.5 -12.5 m). Dissolved oxygen distributins of lake trout between the two periods. levels were obtained in the August survey. Optimal oxygen levels were found at a depth of 11 m and extended to the lakes bottom. 25

20 TEMPERATURE (C), Dissolved Oxygen (mg/L)

0 5 10 15 20 15 0 y

c June n e

u August q e

r 10 F t

n Temperature e c r e

P 5 5 Dissolved Oxygen 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 6 6 8 0 2 4 8 0 2 4 8 0 2 3 4 2 3 3 3 3 4 4 4 4 5

Fork Length (mm) 10 ) m ( h t

500 p e D 450 15 400

350 ) 300 mm ( 20 h 250 t g n e l 200 k r o

F 150

100 25

0 0 5 10 15 20 25 30 Age (year)

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

58 Fish and Wildlife Branch Fisheries Report

Little Atlin Lake 2015 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS Survey results from 2015 indicate the lake trout population in Little Atlin Yukon Headwaters D Lake is small. Bathymetric analysis of Little Atlin Lake indicates that less SURFACE AREA ELEVATION than 20% of this lake is deeper than 20m, which limits lake trout habitat. This may suggest that the lake trout population may not be depleted, 4032 ha 669 m but rather is a small population, limited by habitat availability. MAXIMUM DEPTH AVERAGE DEPTH Conversely, this lake has an abundance of shallow water habitat and is 42 m 10.6 m suitable for northern pike.

SURFACE TEMPS. REGULATIONS Lake Whitefish 18.0OC Special management The lake whitefish population within Little Atlin Lake appears healthy. SAMPLING DATES NET SETS July 7-10, 2015 67 Recommendation The recommendation for future surveys is to increase the amount of net Location sets. This will increase our precision when estimating population size. Little Atlin Lake is located 4 km south on of Another recommendation is to increase thermal habitat mapping of this Jake’s Corner, on the Atlin Road. This lake is lake and increase the number of age structures analyzed. located within the Traditional Territory of the Carcross/Tagish First Nation and the Taku River Tlingit First Nation, in southern Yukon. Program Overview

The Lake Trout Monitoring Program uses the Summer Profundal Index Access and Use Netting (SPIN) method to provide information on lake trout and lake Little Atlin Lake is accessed primarily by a boat whitefish abundance, growth, age and density. ramp, located in the north-east end of the lake. This is a popular destinateion for northern pike This program surveys the two species by placing gill nets throughout fishing. the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 59 Lake Trout Lake Whitefish

Overview Overview A total of 44 lake trout were captured during the survey. A total of 341 lake whitefish were captured during the 2015 These sampled lake trout ranged from 465 mm to 620 mm survey. These fish ranged in size from 240 mm to 470 mm in in fork length, with an average length of 554 mm and an length. Sampled whitefish had an average length of 351 mm average weight of 2,255 g. Age structures were obtained and an average weight of 606 g. Age structures were from 19 lake trout. Ages ranged from 9 to 33 years. obtained from 33 lake whitefish. Ages ranged from 5 to 19 years. Population Estimate / Density 18

The population of lake trout was estimated at7,178 16 (estimate range: 913 – 13,559). This equates to a density of 14 1.8 lake trout per hectare. Given the wide range of our 12 y

c 10 population estimate, we have little confidence in this n e u q

e 8 number. r F t n

e 6 c r e 35 P 4 2 30 0 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 25 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 y

c Fork Length (mm) n 20 e u q e r

F 15 t n e c r e 10 Temperature and Oxygen P

5 Temperature and dissolved oxygen profiles were taken on

0 July 7, 2015. The temperature profile illustrated a strong 5 5 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 2 7 2 7 00 50 2 7 2 7 6 6 6 6 300 3 350 3 400 4 450 4 500 5 550 5 7 72 7 77 800 8 850 8 900 9 950 9 thermocline between 4 m and 8 m, with temperatures 1000 Fork Length (mm) unsuitable for lake trout within the first 5 m. Dissolved oxygen was found to be suitable for lake trout throughout the water column. This indicates suitable habitat from 5 m to 800 the lake’s bottom.

700 Temperature (C), Dissolved Oxygen (mg/L) 600 0.00 5.00 10.00 15.00 20.00 ) 0.00 mm ( 500 h t g

n 5.00 e 400 L k r o F 300 10.00

200 15.00

100 Temperature

) 20.00 m 0 ( Dissolved h 0 5 10 15 20 25 30 35 t

p Oxygen e 25.00 Age (year) D

30.00

35.00

For more information, please contact 40.00

Department of Environment 45.00 Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

60 Fish and Wildlife Branch Fisheries Report

Little Fox Lakes 2016 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS The lake trout populations in the Little Fox Lakes are healthy, containing Yukon Headwaters A(N), B(S) a large density of small-bodied lake trout. The southern basin was found SURFACE AREA ELEVATION to have the largest density of lake trout, in comparison to all previously 227 ha 818 m sampled Yukon lakes. MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 44(N), 50(S) 16.3(N), 10.7(S) m Lake whitefish do not inhabit this system. SURFACE TEMPS. REGULATIONS O 17.1 C Special Management Recommendation SAMPLING DATES NET SETS The recommendation for future surveys of the Little Fox Lakes systems July 4-5,13, 2016 24(N), 30(S) is to perform an Angler Harvest Survey to determine the recreational pressure. It is also recommended that we increase the number of net Location sets to improve the precision of our population estimates. Little Fox Lakes, is a system of two basins (North basin, South basin), located approximately 85 km north of Whitehorse, on Program Overview the North Klondike Highway. This lake system is within the Traditional Territories of the Little The Lake Trout Monitoring Program uses the Summer Profundal Index Salmon Carmacks First Nation, Champagne Netting (SPIN) method to provide information on lake trout and lake Aishihik First Nation, Ta’an Kwäch’än Council whitefish abundance, growth, age and density. and the Kwanlin Dün First Nation. This program surveys the two species by placing gill nets throughout the lake, taking into account both location and depth. Over time, this Access and Use type of sampling allows us to track population changes and evaluate the Little Fox Lakes are accessed through a public health of these species. boat launch, with some private residences along the shores of both basins. These are popular recreational angling lakes.

SR-20-02 61 Lake Trout Lake Whitefish

Overview Overview During the 2016 survey of Little Fox Lakes a total of 28 lake There are no lake whitefish in either the north or south trout were sampled in the north basin and 100 in the south. basins of Little Fox Lakes. Other species known in these The north basin lake trout ranged from 288 mm to 421 mm lakes include arctic grayling and burbot. (averaging 362 mm and 601 g). The south basin sampled ranged between 290 mm to 437 mm (averaging 356 mm and 509 g). Age structures taken from lake trout in both basins (18(N), 41(S)), displaying an age range from 4 to 25 years. Temperature and Oxygen Temperature and dissolved oxygen profiles were taken in Population Estimate / Density both basins. A sharp thermocline occurred between 6 m and The population estimates for lake trout in the Little Fox Lakes 9 m. Dissolved oxygen in both basins showed an increase was1,584 (estimate range: 1,009 – 2,186) in the north basin between 5 m and 10 m, followed by a gradual decline. and12,069 (estimate range: 10,267 – 14,068) in the south. Overall, suitable lake trout habitat existed between 12 m and This resulted in densities of 17 lake trout / ha in the north 40 m. basin and 88 lake trout / ha in the south basin.

North Basin 50.0 South Basin

45.0 Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L)

40.0 0 5 10 15 20 0 5 10 15 20 0 35.0 0 y c n

e 30.0 u

q North Basin

e 5 5 r 25.0 F

t South Basin n

e 20.0 c r e 10 P 15.0 10

10.0

5.0 15 15 ) 0.0 ) m m ( 300 325 350 375 400 425 450 475 500 ( h h t t 20 20 p Fork Length (mm) p e e D D

25 25

500 Temperature Temperature 30 30 450 Dissolved Oxygen Dissolved Oxygen 400 35 35 350 ) 300 40 40 mm (

h 250 t

g North basin n

e 200 L South Basin k r

o 150 F 100 50 0 0 5 10 15 20 25 30

Age (year)

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

62 Fish and Wildlife Branch Fisheries Report

Little Salmon Lake 2015 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters E Results from the 2015 survey of Little Salmon Lake were uncertain and SURFACE AREA ELEVATION as a result, we have little confidence in our population estimate. This was in part due to the bathymetric properties of the lake, which are very 6,321 ha 885 m deep with a steep gradient. These properties make it difficult to apply MAXIMUM DEPTH AVERAGE DEPTH the SPIN methodology approriately. N/A 92.6 m

SURFACE TEMPS. REGULATIONS Lake Whitefish 11.46OC Special management We also had difficulty sampling lake whitefish. This resulted in an insufficient number being sampled to generate an accurate population SAMPLING DATES NET SETS estimate. July 30-Aug 6, 2015 143 Recommendation Location The recommendation for future surveys is to increase the amount of net Little Salmon Lake is located in central Yukon, sets, as well as obtain more lake trout samples. It is anticipated that between Carmacks and Faro, off of the Robert future surveys will also encounter the same sampling difficulty, however Campbell Highway. This lake is located within we may be able to overcome this by increasing the number of fish the Traditional Territory of the Little Salmon/ sampled. We would gain more information on the age structure of the Carmacks First Nation and the Kaska Dena population, along with natural mortality rates. Council.

Access and Use Program Overview Little Salmon Lake is accessed primarily from two campgrounds (Drury Creek and Little The Lake Trout Monitoring Program uses the Summer Profundal Index Salmon), both of which have accessible boat Netting (SPIN) method to provide information on lake trout and lake ramps. There are a number of residences whitefish abundance, growth, age and density. along the lake. There was a commercial fishing This program surveys the two species by placing gill nets throughout operation on the lake, which closed in 1969, the lake, taking into account both location and depth. Over time, this which had operated with a quota of 2,727 kg. type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 63 Lake Trout Lake Whitefish

Overview Overview There were a total of 74 lake trout sampled during this A total of 15 lake whitefish were sampled during the 2015 survey. These fish ranged in size (fork length) from 310 mm survey. They ranged in size from 270 mm to 576 mm in to 649 mm. They had an average length of 434 mm and an length, with an average fork length of 463 mm and an average weight of 988 g. Age structures were obtained from average weight of 1,483 g. Age structures obtained from 9 31 lake trout. Ages ranged from 7 to 20 years. fish. Ages ranged from 6 to 30 years.

30 Population Estimate / Density The population estimate for lake trout within Little Salmon 25 Lake was estimated at10,008 (estimate range from 232 – 20

19,947). This equates to a density of 1.6 lake trout per y c 15 n e u hectare. Given the range of the estimate, we have little q e r F 10 t confidence in this population number. n e c r e

P 5

14 0 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 12 Fork Length (mm) 10

8 y c Temperature and Oxygen n e

u 6 q e r F

t 4 Temperature and dissolved oxygen profiles were taken at n e c r

e three locations (west, central, east). The temperature profiles

P 2 were similar. A thermocline was evident between 7.5 m and 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 12 m across the lake. The dissolved oxygen profiles were 0 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0

1 relatively stable through the water column. We were unable

Fork Length (mm) to determine temperature and dissolved oxygen at depths greater than 60 m as that was the limit for our instruments.

800

700 West Profile Central Profile East Profile

Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 20 0 5 10 15 20 ) 600 0 5 10 15 20 0 0 0 mm ( 500 h t

g 10 10 n 10 e

L 400 k r o

F 20 20 20 300 Temperature Temperature Temperature ) ) ) m m m ( ( 200 ( Dissolved Dissolved Dissolved h h h t t t 30 30 30 Oxygen Oxygen Oxygen p p p e e e D D D 100 40 40 40 0 0 5 10 15 20 25 50 50 50 Age (year)

60 60 60

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

64 Fish and Wildlife Branch Fisheries Report

Louise (Jackson) Lake 2011 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters A The 2011 survey results indicate there is a small population of lake SURFACE AREA ELEVATION trout in Louise Lake. This lake is a popular angling destination and is potentially at risk for over harvest (given the current catch limits). 68 ha 1020 m

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 13 m 6.8 m During the 2011 survey, there were no lake whitefish captured. Additional species sampled included arctic grayling and round SURFACE TEMPS. REGULATIONS whitefish. 11.7OC Special management

SAMPLING DATES NET SETS Recommendation July 27-29, 2011 24 The recommendation from the 2011 survey is to increase the number of net sets used on subsequent surveys to increase our precision when making population estimates. It is also Location recommended that catch limits are reduced through regulation Louise Lake (locally known as Jackson) is changes. This will assist in maintaining this population. located approximately 12 km west of Whitehorse, off the Fish Lake Road. The lake is within the Traditional Territory of the Program Overview Kwanlin Dün First Nation. The Lake Trout Monitoring Program uses the Summer Profundal Access and Use Index Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. There are several private residences, mostly along the north shoreline. There are no formal This program surveys the two species by placing gill nets campgrounds, day use areas or boat launches throughout the lake, taking into account both location and depth. on the lake. The lake drains via Porter Creek to Over time, this type of sampling allows us to track population the northeast where flows get diverted changes and evaluate the health of these species. through a micro-hydroelectric generating facility into McIntyre Creek, part of the Yukon River system.

SR-20-02 65 Lake Trout Lake Whitefish

Overview Overview A total of 40 lake trout were sampled during the survey. No lake whitefish were captured during the 2011 survey. These fish ranged in fork length from 270 mm to 670 mm. This may explain why this lake contains small-bodied lake The sampled fish had an average length of 409 mm and trout. average weight of 971 g. Age structures were obtained from 15 lake trout. Ages ranged from 7 to 26 years.

Population Estimate / Density Temperature and Oxygen The lake trout population in Louise Lake was estimated at The lake was strongly stratified in the larger basin, with a 2,024 (estimate range from 1,534 – 2546). This equates to a thermocline from 6.5 m – 9.5 m. The small basin was not density of 29.8 lake trout per hectare. Lake trout found in stratified. Oxygen profiles did not fall below 4 mg/L. Louise lake were of the small-bodied type. However, below 7 m oxygen levels did drop beneath 7mg/L.

0.2

0.18 Large Basin Small Basin 0.16 y

c Temperature (C), Dissoled Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) n 0.14 e 0 5 10 15 20 0 5 10 15 20 u 0 q 0

e 0.12 r

0.1 2 2 0.08 Percent F 0.06

4 4 0.04 ) 0.02 ) m m ( ( h h

t 6 6 t

0 p p e e 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 D 1 3 5 7 5 7 9 1 3 5 7 9 1 3 5 7 9 1 3 5 7 9 D 6 6 6 6 2 2 2 3 3 3 3 3 4 4 4 4 4 5 5 5 5 5

Fork Length (mm) 8 8 Temperature Temperature Dissolved Oxygen Dissolved Oxygen 10 10

700 12 12

600

500 ) mm

( 400 h t g n

e 300 L k r o

F 200

100

0 0 5 10 15 20 25 30 Age (year)

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

66 Fish and Wildlife Branch Fisheries Report

Mandanna Lake 2013 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS The lake trout population in Mandanna Lake was found to have a Yukon Headwaters B moderate density when compared to lakes of similar size. This indicates SURFACE AREA ELEVATION that the population is healthy. Although these lake trout were slightly smaller than lake trout in comparable lakes, the observed age/length 786 ha 781 m data suggests this may be typical for this lake. MAXIMUM DEPTH AVERAGE DEPTH 64 m 21 m Lake Whitefish The lake whitefish population in Mandanna Lake was found to be of SURFACE TEMPS. REGULATIONS moderate to low density when compared to similar sized lakes. O 18.01 C Special management However their size was slightly larger. Overall this population appears SAMPLING DATES NET SETS healthy. August 18-22, 2013 48 Recommendation Location It is recommended to increase the number of net sets to improve the accuracy of population estimates and to obtain more age structures for Mandanna Lake is located within central analysis. Yukon, approximately 30 km southeast Carmacks, within the Little Salmon/Carmacks First Nation Traditional Territory. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Mandanna Lake can be accessed by float Netting (SPIN) method to provide information on lake trout and lake plane in the summer and snowmachine in the whitefish abundance, growth, age and density. winter months, along the Yukon Quest trail system. Management of Mandanna Lake is This program surveys the two species by placing gill nets throughout guided by theManadanna Lake Management the lake, taking into account both location and depth. Over time, this Plan. type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 67 Lake Trout Lake Whitefish

Overview Overview A total of 94 lake trout were captured during this survey of During this survey, 31 lake whitefish were sampled. The Mandanna Lake. These lake trout were of the large-bodied sampled lake whitefish ranged in fork length from 449 mm form and ranged in fork length from 261 mm to 770 mm. to 530 mm, with an average length of 491 mm and average They had an average length of 487 mm and average weight weight 1,692 g. The lake whitefish in Mandanna Lake were 1,439 g. Age structures were obtained from 22 lake trout. larger than other Yukon lakes of comparable size. Age Ages ranged from 9 to 30 years. structures were analyzed from 17 lake whitefish. Ages ranged from 7 to 17 years. Population Estimate / Density The population estimate for lake trout was 3,487 (estimate 50 range: 2,123 – 4,903). This equates to a density of 4.4 lake 45 trout per hectare. This suggests the population is healthy. 40 35 y c n e 30 u q e r

F 25

12 t n e

c 20 r e 10 P 15 10 y

c 8

n 5 e u q e

r 0

F 6 5 5 5 5 5 5 5 5 5 5 5 5 t 00 2 50 7 2 7 00 50 2 7 2 7 2 7 00 n 6 6 6 6 1 150 1 2 22 2 27 300 3 350 3 400 4 450 4 500 5 550 5 7 e c r e 4 P Fork Length (mm) 2 Temperature and Oxygen

0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0 Temperature and dissolved oxygen profiles were taken near 1 the middle of Mandanna Lake on August 18, 2013. The lake Fork Length (mm) was stratified with the thermocline between 5 m and 8 m. Temperatures were unsuitable for lake trout between the surface and 6 m, with dissolved oxygen levels being suitable 700 from the surface to a depth of 56 m.

600 Temperature (C), Dissolved Oxygen (mg/L)

) 500 0 10 20 mm 0.0 ( h t 400 g n e L k

r 300 10.0 o F

200 20.0 100 ) m ( h

0 t 30.0 p

0 5 10 15 20 25 30 35 e D Age (year) 40.0 Temperature

Dissolved Oxygen 50.0 For more information, please contact

Department of Environment 60.0 Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

68 Fish and Wildlife Branch Fisheries Report

Marsh Lake 2015 Lake Trout Monitoring Program

Overall Status

Lake Trout Lake Information In accordance with the 2015 survey, the lake trout population in Marsh Lake was smaller than expected. This lake has a higher productivity WATERSHED LAKE CLASS value than the other southern lakes (Bennett and Tagish), however Yukon Headwaters E Marsh Lake has a shallower profile. This may indicate less available SURFACE AREA ELEVATION habitat for lake trout and their top prey, lake whitefish. As such, this population may not be small in number due to angling pressure but 2,015 ha 660 m rather naturally small, due to a lack of available habitat.

MAXIMUM DEPTH AVERAGE DEPTH 51.5 m 12.8 m Lake Whitefish The 2015 Marsh Lake survey indicated a small population of lake SURFACE TEMPS. REGULATIONS whitefish. However, this species prefers depths which are greater than O 15.2 C Conservation waters 20 m, of which there is a limited amount of habitat in Marsh Lake. SAMPLING DATES NET SETS Therefore, it is likely that this population is limited based on habitat availability. July 13-18, 2015 149

Location Recommendation Marsh Lake is located 50 km south of The recommendation for future surveys is to perform an Angler Harvest Whitehorse, along the Alaska Highway in Survey on the southern lakes system to gauge angling pressure. In southern Yukon. Marsh Lake is within the addition, these results should be incorporated into the Southern Lakes Traditional Territories of the Carcross/Tagish Lake Trout Telemetry, to compare seasonal habitat usage. First Nation and the Kwanlin Dün First Nation.

Access and Use Program Overview Marsh Lake is accessed along the Alaska The Lake Trout Monitoring Program uses the Summer Profundal Index Highway, with three accessible boat ramps Netting (SPIN) method to provide information on lake trout and lake along the lake. The lake also has a government whitefish abundance, growth, age and density. campground at the northern end, along with a high number of residences along the lake, This program surveys the two species by placing gill nets throughout when compared to all other Yukon lakes. the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species. SR-20-02 69 Lake Trout Lake Whitefish

Overview Overview A total of 108 lake trout were sampled during this survey. A total of 46 lake whitefish were captured during the 2015 These sampled fish ranged in size (fork length) from 265 mm survey. They ranged in size from 240 mm to 520 mm in to 669 mm. The average length was 552 mm and the length, with an average fork length of 430 mm and an average weight was 2,212 g. Age structures were obtained average weight of 1,139 g. Age structures were obtained from 38 lake trout. Ages ranged from 6 to 30 years. from 14 lake whitefish. Ages ranged from 4 to 17 years.

Population Estimate / Density 25

The population of lake trout within Marsh Lake was 20 estimated at17,392 (estimate range: 2,532 – 32,525). This

equates to a density of 1.8 lake trout per hectare. cy

n 15 e qu e r

F 10

25 t n ce r

e 5

20 P y

c 0 n 15 e 5 0 5 0 5 0 5 0 5 0 5 0 u 5 75 5 75 00 2 5 75 00 2 00 2 00 q 12 1 1 200 22 2 2 3 3 35 375 400 42 4 4 5 5 55 575 6 6 65 675 7 e r

F Fork Length (mm)

t 10 n e c r e

P 5

0 Temperature and Oxygen 5 5 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 2 7 2 7 00 50 2 7 2 7 6 6 6 6 300 3 350 3 400 4 450 4 500 5 550 5 7 72 7 77 800 8 850 8 900 9 950 9 1000 Temperature and dissolved oxygen profiles were taken on Fork Length (mm) July 13. The temperature profile indicated a sharp

800 thermocline between 19 m and 22 m, followed by a gradual temperature decline to 60 m. Dissolved oxygen levels were 700 stable throughout the profile.

) 600 mm ( 500 h t Temperature (C), Dissolved Oxygen (mg/L) g n

e 0.00 5.00 10.00 15.00 20.00

L 400 0 k r o F 300

200 10 100

0 0 5 10 15 20 25 30 35 20 Age (year) Temperature

) Dissolved m ( Oxygen h

t 30 p e D

For more information, please contact 50 Department of Environment Fish and Wildlife, Fisheries [email protected] 60 867-667-5652

SR-20-02 Table of Contents

70 Fish and Wildlife Branch Fisheries Report

Mayo Lake 2013 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Stewart E The lake trout population in Mayo Lake was found to be smaller in SURFACE AREA ELEVATION number than other comparably sized Yukon lakes. However our 9963 ha 583 m confidence in the population estimate is weak. This may be due to the morphology of the lake, making it difficult to thoroughly sample. MAXIMUM DEPTH AVERAGE DEPTH 106 m 56.5 m Lake Whitefish SURFACE TEMPS. REGULATIONS The lake whitefish population appeared healthy, however this 15.1OC Conservation waters population is also difficult to assess.

SAMPLING DATES NET SETS Recommendation July 24 - Aug 4, 2013 140 The recommendation from this survey is to increase the number of agre structures obtained and analyzed. This will allow for increased Location knowledge of the population structure and further management of the Mayo Lake is located in central Yukon, lake trout and lake whitefish populations within this lake. approximately 50 km northwest of Mayo, within the Traditional Territory of the First Nation of Na-Cho Nyäk Dun. Mayo Lake is the Program Overview reservoir for the Mayo electrical generating station and as such, the lake levels are The Lake Trout Monitoring Program uses the Summer Profundal Index controlled by this facility. Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Access and Use This program surveys the two species by placing gill nets throughout Mayo Lake is primarily accessed from the the lake, taking into account both location and depth. Over time, this public boat launch at the west end of the lake, type of sampling allows us to track population changes and evaluate the near the hydro dam. There are several private health of these species. residences along the northwest shore of the lake.

SR-20-02 71 Lake Trout Lake Whitefish

Overview Overview A total of 123 lake trout were captured during this survey. During this survey, 72 lake whitefish were captured. The The sampled lake trout ranged in size from 250 mm to 835 captured lake whitefish ranged from 385 mm to 525 mm in mm in fork length, with an average length of 456 mm and fork length, with an average length of 430 mm and average average weight 1,261 g. Age structures were obtained from weight 1,175 g. Age structures from 39 lake whitefish. Ages 42 individuals. Ages ranged from 6 to 41 years. ranged from 7 to 30 years.

40% Population Estimate / Density 35%

The population of lake trout within Mayo Lake was estimated 30%

tobeat21,229 (estimate range: 5,603 – 37, 202). This y

c 25% n e equates to a density of 2.1 lake trout per hectare, however u q e

r 20% F there was a low confidence level with this population t n e c

r 15% e

estimate, as evident by the wide range. P 10%

14% 5%

12% 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 25 27 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 Fork Length (mm) 10% y c n e

u 8% q e r F t n

e 6% c

r Temperature and Oxygen e P 4% Temperature and dissolved oxygen profiles were taken

2% within the Main arm, Roop arm and Nelson arm of the lake. Each of the three lake arms, were stratified in temperature, 0%

0 displaying a thermocline between 6 m and 12 m in depth. 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 25 27 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 Dissolved oxygen levels were found to be suitable for lake Fork Lenth (mm) trout throughout the water column in all three arms.

900

800 Main Arm Nelson Arm Roop Arm

Temperature ( oC), DIssolved Oxygen (mg/L) Temperature (C), DIssolved Oxygen (mg/L) Temperature (C), DIssolved Oxygen (mg/L) 700 0 5 10 15 20 0 5 10 15 20 0 5 10 15 20 0 0 0

600 10 10

) 10 m (

h 20 t 500 20 20 g n e L 400 30 30 30 k r ) ) ) o m m m F ( ( ( h h 40 h

t 40 40 t t p p p 300 e Temperature e e D D D Dissolved Oxygen 50 50 50 200

60 60 60 100

70 70 70 0

0 5 10 15 20 25 30 35 40 45 80 80 80 Age (year)

90 90 90

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

72 Fish and Wildlife Branch Fisheries Report

Michie Lake 2017 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters B In accordance with the 2017 survey results, Michie Lake has a small to SURFACE AREA ELEVATION moderate sized population of lake trout, when compared to similar sized 371 ha 795 m lakes.

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 50 m N/A The population of lake whitefish within Michie Lake appears healthy and SURFACE TEMPS. REGULATIONS stable, given the small size of the lake. 15.55OC General waters

SAMPLING DATES NET SETS Recommendation July 10-13, 2017 43 The recommendation for future surveys of Michie Lake is to increase net sets. This will help improve our confidence in the population estimate. Additional habitat information will help quantify viable lake trout habitat Location for this population. Michie Lake is located approximately 50 km southeast of Whitehorse. Michie lake lies within the Traditional Territories of the Ta’an Program Overview Kwach’an Council and the Kwanlin Dun First Nation. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Access and Use whitefish abundance, growth, age and density. Michie Lake is accessed by a 4x4/ATV trail, This program surveys the two species by placing gill nets throughout which branches off from the M’Clintok River the lake, taking into account both location and depth. Over time, this agricultural area. There is a small trappers type of sampling allows us to track population changes and evaluate the cabin and rough campsite on the northern health of these species. shore.

SR-20-02 73 Lake Trout Lake Whitefish

Overview Overview During the 2017 survey of Michie Lake, a total of seven lake During the 2017 survey, a total of 63 lake whitefish were trout were sampled. These sampled fish were large-bodied sampled. The size of these fish ranged in fork length from lake trout and ranged in fork length from 494 mm to 631 320 mm to 477 mm, with an average length of 377 mm and mm. They had an average length of 543 mm with an average an average weight of 728 g. Age structures were obtained weight of 2,082g. Age structures were only obtained from from 29 lake whitefish. Ages ranged from 6 to 35 years. three lake trout, with ages of 10, 24 and 25.

Population Estimate / Density 30 y

The population estimate of lake trout within Michie Lake, c

n 25 e u was562 (estimate range: 0 to 1,144). This equates to a q e r

F 20 density of 1.5 lake trout per hectare. However our t n e c r confidence in the population estimate is weak. e 15 P

10 50 45 5 40 0 0 5 0 5 35 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7

y 30 c

n Fork Length (mm) e

u 25 q e r

F 20 t n

e 15 c r e P 10 Temperature and Oxygen 5 0 Temperature and dissolved oxygen profiles were obtained on 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0 July 13. The temperature profile displayed a sharp 1 thermocline from 5 m to 9 m, followed by a gradual decline Fork Length (mm) through the water column. Dissolved oxygen displayed a slight increase from 6 m to 8 m. Overall, optimum habitat for 700 lake trout existed from 7 m to 50 m.

600

) Temperature (C), Dissolved Oxygen (mg/L) 500 0 5 10 15 20 mm ( 0 h t

g 400 n e

L 5 k r o 300 F 10 200 15

100 20 Temperature ) m 0 ( h Dissolved t 25

0 5 10 15 20 25 30 p

e Oxygen D Age (year) 30

For more information, please contact 50 Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

74 Fish and Wildlife Branch Fisheries Report

Minto Lake 2014 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Stewart B The lake trout population in Minto Lake was smaller than expected for a SURFACE AREA ELEVATION lake of this size. However this is a small unproductive lake, which would not naturally support a large population. As such, regulations that 6761 m 420 ha promote a conservative approach to harvest should be established. This MAXIMUM DEPTH AVERAGE DEPTH will help support a sustainable fishery. 37 m 13.8 m Lake Whitefish SURFACE TEMPS. REGULATIONS The population of lake whitefish in Minto Lake appears healthy, although 15.8OC Special management smaller in physical size, compared to other populations from similar SAMPLING DATES NET SETS sized lakes. July 16-18, 2014 34 Recommendation Location To improve confidence in the population estimate, we recommend that for future surveys, to increase the amount of net sets. This will increase Minto Lake is a small lake located about 16 km our sample size, however as this is a small population, caution should be north-west of the community of Mayo, in taken when setting nets, to ensure minimal mortalities. central Yukon. Minto Lake is within the Traditional Territory of the First Nation of Na- cho Nyäk Dun. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Minto Lake is accessible from an unpaved road Netting (SPIN) method to provide information on lake trout and lake off the Silver Trail. There are several seasonal whitefish abundance, growth, age and density. residences along the lake and a small boat This program surveys the two species by placing gill nets throughout launch along the east shore. Recreational the lake, taking into account both location and depth. Over time, this angling has not been assessed on this lake. type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 75 Lake Trout Lake Whitefish

Overview Overview During the 2014 survey, a total of 14 large-bodied lake trout During this survey 56 lake whitefish were sampled. The were sampled. These fish ranged in fork length size from sampled lake whitefish ranged in fork length from 230 mm 394 mm to 799 mm. These sampled fish had an average to 368 mm. They had an average length of 298 mm and an length of 674 mm and an average weight of 3,927g. Age average weight of 385 g. Age structures were obtained from structures were only obtained from a single lake trout, which 13 lake whitefish. Ages ranged from 6 to 18 years. was 7 years old. 60

Population Estimate / Density 50

The population estimate of lake trout in Minto Lake was y c 40 n e u

1,062 (estimate range: 396 – 1,745). This equates to a q e r

F 30 density of 2.5 lake trout per hectare. This represents a small t n e c r population, however we have little confidence in this e P 20 estimate.

35 0 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 00 50 2 7 2 7 2 7 00 6 6 6 6 30 1 150 1 2 22 2 27 300 3 350 3 400 4 450 4 500 5 550 5 7

Fork Length (mm)

y 25 c n e u

q 20 e r F t

n Temperature and Oxygen

e 15 c r e P 10 The temperature profile showed a strongly stratified water

5 column, with a thermocline evident between 7 m and 10 m. The dissolved oxygen levels were relatively stable down to 0 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 a depth of 30 m, at which point they decreased. Overall, 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 1 there was suitable habitat for lake trout below 6 m. Fork Length (mm)

Temperature (C), Dissolved Oxygen (mg/L) 0.00 5.00 10.00 15.00 20.00 0

) 15 Temperature m ( h t p

e Dissolved D 20 Oxygen

For more information, please contact 35 Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

76 Fish and Wildlife Branch Fisheries Report

Morley Lake 2018 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters C The lake trout population in Morley Lake was low to moderate in SURFACE AREA ELEVATION density, when compared to lakes of similar size and productivity. This population of large-bodied lake trout appears healthy. 1,114 ha 814 m

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 30 m 8.07 m The population of lake whitefish in Morley Lake appears healthy. There was a large density of lake whitefish, with a large availability of suitable SURFACE TEMPS. REGULATIONS habitat. 15.6OC Conservation waters

SAMPLING DATES NET SETS Recommendation July 09-12, 2018 34 The recommendation for future surveys is to increase net sets and obtain a greater number of aging structures to analyze. This will give us Location a larger sample size from which to base our population estimates upon. Morley Lake is located approximately 220 km Our current confidence in the population estimate is low. An Angler southeast of Whitehorse, along the Alaska Harvest Survey would assist in determining recreational pressure for the Highway, in south-central Yukon. Morley Lake lake. is within the Traditional Territory of the Teslin Tlingit Council, with the southern end of the lake crossing into British Columbia. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Morley Lake is accessed via the Morley Lake whitefish abundance, growth, age and density. Recreational Site, located on the southwest shore. This location contains camping sites This program surveys the two species by placing gill nets throughout and a gravel shoreline, which can be used as a the lake, taking into account both location and depth. Over time, this boat ramp. The rest of the lake shoreline is type of sampling allows us to track population changes and evaluate the undeveloped. health of these species.

SR-20-02 77 Lake Trout Lake Whitefish

Overview Overview A total of 37 lake trout were sampled. These large-bodied During the 2018 survey, a total of 78 lake whitefish were lake trout ranged in fork length from 279 mm to 714 mm. sampled in Morley Lake. The size of these fish ranged from They had an average length of 482 mm with an average 226 mm to 492 mm, and had an average fork length of 377 weight of 1,367g. Age structures were obtained from 23 mm and an average weight of 750 g. Age structures were lake trout. Ages ranged from of 5 to 40 years. obtained rom 34 sampled lake whitefish. Ages ranged from 3 to 26 years. Population Estimate / Density 30 The population estimate of lake trout within Morley Lake was 25 3,963 (estimate range: 2,122 - 5,868). This corresponds to a y c n e

density of 3.6 lake trout per hectare. u

q 20 e r F t n

e 15 c r e P

30 10

25 5 y c n e u

q 20 0 e r 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 F 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 t 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 n e

c 15 r

e Fork Length (mm) P

5 Temperature and Oxygen

0 Temperature and dissolved oxygen profiles showed a sharp 5 5 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 2 7 2 7 00 50 2 7 2 7 6 6 6 6 300 3 350 3 400 4 450 4 500 5 550 5 7 72 7 77 800 8 850 8 900 9 950 9 thermocline between 8 m and 9 m, followed by a gradual 1000 Fork Length (mm) temperature decline throughout the water column. Dissolved oxygen remained relatively constant. Optimal lake trout

900 habitat existed from 9 m to lake bottom.

800

700 Temperature (C), Dissolved Oxygen (mg/L) ) 0 5 10 15 20

mm 600 ( 0 h t

g 500 n e L k

r 400

o 5 F 300

200 10 100

0 0 5 10 15 20 25 30 35 40 45 15 Temperature ) m Age (year) ( h t Dissolved p e Oxygen D 20

30 For more information, please contact

Department of Environment 35 Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

78 Fish and Wildlife Branch Fisheries Report

Quiet Lake 2012 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters E The lake trout population in Quiet Lake appears healthy. The 2012 SURFACE AREA ELEVATION survey results indicate that this large-bodied lake trout population is 5441 ha 787 m stable. This lake recieves minimal angler effort.

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 170 m 56.8 m The lake whitefish population in Quiet Lake was lower in number when SURFACE TEMPS. REGULATIONS compared to similarly sized Yukon lakes. This may be related to 11.4OC Conservation waters commercial fishing operations which occurred from 1961 - 1989, which included a yearly quota of 2,722kg of lake whitefish. SAMPLING DATES NET SETS Recommendation July 16-20, 2012 102 The recommendation from the 2012 survey is to slightly increase the Location number of net sets and collection of aging stuctures, if this lake is Quiet Lake is located approximately 60 km sampled in the future. This will improve the accuracy of the population north of Johnson’s Crossing in south-central estimate. Yukon, along the South Canol Highway. Quiet Lake is within the Traditional Territory of the Teslin Tlingit First Nation and the Kaska Dena Program Overview Nation (northern section of the lake). The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Access and Use whitefish abundance, growth, age and density. Access to Quiet Lake is via the South Canol Road, which is only open to vehicles in the This program surveys the two species by placing gill nets throughout summer season and not maintained in the the lake, taking into account both location and depth. Over time, this winter. There are two government type of sampling allows us to track population changes and evaluate the campgrounds along the lake with two health of these species. available boat launches.

SR-20-02 79 Lake Trout Lake Whitefish

Overview Overview During the survey, a total of 162 lake trout were captured, A total of 42 lake whitefish were captured during this survey, ranging from 231 mm to 949 mm in fork length. They had an ranging from 352 mm to 544 mm in fork length, with an average length of 519 mm and an average weight of 1,852 average length of 454 mm and average weight of 1,270 g. g. Age structures were obtained from 37 lake trout during Age structures were analyzed from 4 lake whitefish. Ages the 2012 survey. Ages ranged from 8 to 32 years. ranged from 7 to 31 years.

Population Estimate / Density 30 The lake trout population within Quiet Lake was estimated to 25 y be17,865 (estimate range: 8,951 – 27,071). This equates to c n e a density of 3.3 lake trout per hectare. u 20 q e r F t

n 15 e c r e

P 10

16 5

14 0 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 12 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 y c n

e 10 Fork Length (mm) u q e r

F 8 t n e c r

e 6 P Temperature and Oxygen 4

2 Temperature and dissolved oxygen profiles were taken near the middle of Fish Lake on July 17, 2012. The lake was not 0 stratified in temperature. Dissolved oxygen levels declined between 9 and 17 m. Fork Length (mm)

700 South Basin North Basin

600 Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 20 0 5 10 15 20 0 0 ) 500 mm ( h t 10 g 400 10 n e L k r

o 300

F 20 20

200

) 30

) 30 m m ( ( h

100 h t t p p e e D 40 D 40 0 0 5 10 15 20 25 30 35

Age (year) 50 50

Temperature 60 60

Dissolved Oxygen

70 70

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

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80 Fish and Wildlife Branch Fisheries Report

Snafu Lake (lower) 2010 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters B No lake trout were sampled during the survey of Snafu Lake. This SURFACE AREA ELEVATION indicates the lake trout population may have collapsed. Historically, constant fishing pressure from commerical and recreational angling 248 ha 759 m may have led to this decline. MAXIMUM DEPTH AVERAGE DEPTH 25 m 6.3 m Lake Whitefish Snafu Lake was found to contain a healty population of lake SURFACE TEMPS. REGULATIONS whitefish. They likely form the primary diet of northern pike in this Not available Special management lake. Other sampled fish included: broad whitefish, arctic grayling, SAMPLING DATES NET SETS least cisco and northern pike. July 5-6, 2010 22 Recommendation The recommendation from the 2010 survey is to present a Location regulation change to prohibit retention of lake trout on this lake. Snafu Lake (lower) is located approximately This lake cannot sustain lake trout harvest at this time. 25 km southeast of Jakes Corner along the Atlin Road. The lake belongs to a chain of lakes collectively referred to as Snafu Lakes. Program Overview The lakes are within the Traditional Territory of the Carcross/Tagish First Nation. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout Access and Use and lake whitefish abundance, growth, age and density. Access to Snafu Lake (lower) is from the Atlin This program surveys the two species by placing gill nets Road. This lake has a popular government throughout the lake, taking into account both location and depth. campground and an accessible boat ramp. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 81 Lake Trout Lake Whitefish

Overview Overview No lake trout were sampled during this survey. The lack of During this survey, 96 lake whitefish were captured, ranging lake trout captured indicates a collapsed population in this in fork length size from 220 mm to 470 m in length. Aging lake. This information agrees with results from Angler structures for lake whitefish were not obtained in 2010. Harvest Surveys, which documented small numbers of lake However, given the large number sampled, it is believed that trout in the catch composition. this population is healthy.

Population Estimate / Density 14 As no lake trout were captured, population estimates can not 12 be derived.

y 10 c n e u q e

r 8 F

6 Percent

Fork Length (mm)

Temperature and Oxygen Temperature and oxygen profiles were not assessed during the 2010 survey as this equipment was not available at the time.

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

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82 Fish and Wildlife Branch Fisheries Report

Snafu Lake (Gazetted) 2018 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters B The results from this survey suggest that the lake trout population is healthy, although the population is not large. The lake trout population is SURFACE AREA ELEVATION likely healthy due to the inaccessibility of this lake. 475 ha 878 m Lake Whitefish MAXIMUM DEPTH AVERAGE DEPTH 35 m 14.7 m The population of lake whitefish within Gazetted Snafu Lake consists of a large number of smaller whitefish. This population is currenlty healthy. SURFACE TEMPS. REGULATIONS 14–17ºC General waters Recommendation SAMPLING DATES NET SETS No change in current regulation. Due to the inaccessability of this lake, July 6–11, 2018 47 this lake is a good candidate lake to be used as a control when studying lakes such as Snafu Lake and Tarfu Lake. Location Gazetted Snafu is located in the Southern Lakes region and is within the Traditional Program Overview Territories of the Teslin Tlingit Council and the Carcross/Tagish First Nation. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Access and Use whitefish abundance, growth, age and density. Gazetted Snafu is difficult to access and This program surveys the two species by placing gill nets throughout receives little to no recreational angling the lake, taking into account both location and depth. Over time, this pressure. type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 83 Lake Trout Lake Whitefish

Overview Overview There were 48 lake trout sampled during the survey, ranging There were 262 lake whitefish captured during the survey, from 400 mm to 815 mm in length (as measured to the fork). ranging from 200 mm to 474 mm in length (as measured to Seventeen were sampled for age. Ages ranged from 7 to 28 the fork). Fifty three were sampled for age. Ages ranged years. from 3 to 37 years.

Population Estimate / Density 45 The lake trout population estimate was approximately1,560 40 (estimate range: 781 – 2364). The estimated density of lake 35 trout is 3.3 per hectare. 30 25 20 15 20 Percent Frequency 10 18 5 16 0 25 50 75 00 25 50 75 00 25 50 75 00 25 50 75 00 25 50 75 00 00 25 50 75

14 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 6 6 6 6 7 Fork Length (mm) 12 10 8 6 Temperature and Oxygen Percent Frequency 4 Temperature at the lake surface was close to 15OC, declining 2 slowly over 8 m, with a thermocline noted between 6 m and 0 10 m. An oxygen profile was not conducted due to equipment

25 75 25 75 25 75 25 75 25 75 25 75 25 75 3 3 4 4 5 5 6 6 7 7 8 8 9 9 malfunction. Fork Length (mm)

TEMPERATURE (°C)

700 0 5 10 15 20 600 0

500 5 400 10 300

200 ) M 15 Fork Length (mm) ( H

100 T P

E 20 0 D 0 5 10 15 20 25 30 Age (yr) 25

40 For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

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84 Fish and Wildlife Branch Fisheries Report

Tagish Lake 2015 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters F Tagish Lake is one of the largest lakes in Yukon and the lakes multiple SURFACE AREA ELEVATION basins and depth make it difficult to effectively sample lake trout populations using the SPIN program. The lake trout population in Tagish 662 m 35,458 ha Lake appears healthy. It has a large-bodied population. Numbers are MAXIMUM DEPTH AVERAGE DEPTH similar to lakes of comparable size (Kluane, Atlin). 307 m 12.8 m Lake Whitefish SURFACE TEMPS. REGULATIONS The 2015 Tagish Lake survey results indicate a healthy population of 14.2OC Conservation waters lake whitefish. There is significant available habitat for this species. This SAMPLING DATES NET SETS population had similar catch rates as other Yukon lakes of this size. August 8-14, 2015 140 Recommendation Location The recommendation for future surveys is to perform an Angler Harvest Tagish Lake is a large lake with multiple basins Survey on the southern lakes system to gauge angling pressure. (Windy Arm, Taku Arm, Nares, Graham Inlet, Moose Arm), located in southern Yukon. This is a transboundary lake with British Columbia Program Overview and is within the Traditional Territory of the Carcross/Tagish First Nation and the Taku The Lake Trout Monitoring Program uses the Summer Profundal Index River Tlingit First Nation. Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Access and Use This program surveys the two species by placing gill nets throughout Tagish Lake is accessed via the South Klondike the lake, taking into account both location and depth. Over time, this Highway and Tagish Road. Main access points type of sampling allows us to track population changes and evaluate the are at Carcross and Tagish. There are two health of these species. government campgrounds and multiple boat ramps on this lake. There are multiple private residences found along this lake.

SR-20-02 85 Lake Trout Lake Whitefish

Overview Overview A total of 149 lake trout were sampled during the 2015 A total of 41 lake whitefish were captured during the 2015 survey. These lake trout ranged in size (fork length) from 243 survey. They ranged in size from 200 mm to 510 mm in fork mm to 805 mm. Sampled fish had an average length of 480 length, with an average length of 419 mm and an average mm and an average weight of 1,438 g. Age Structures were weight of 1,036 g. Age structures were only obtained from 4 obtained from 37 lake trout. Ages ranged from 5 to 25 years. lake whitefish. Ages ranged from 8 to 19 years.

Population Estimate / Density 25 The population estimate for lake trout in Tagish Lake was 20 162,460 (estimate range: 100,263 – 227,310). This equates to a density of 4.6 lake trout per hectare. Given the wide

y 15 c n

range of our population estimate, we believe the strength of e u q e this estimate can be improved. r F 10 t n e c r e P 5

16 0 5 5 5 5 5 5 5 5 5 5 5 5 00 2 50 7 2 7 00 50 2 7 2 7 2 7 00 6 6 6 6 14 1 150 1 2 22 2 27 300 3 350 3 400 4 450 4 500 5 550 5 7

y Fork Length (mm) c 12 n e u q

e 10 r F t

n 8 e c r

e Temperature and Oxygen P 6 4 Temperatureand dissolved oxygen profiles were taken at five 2 locations (Racine River, Graham Inlet, Engineer, Windy Arm 0 and the main basin). Profiles at Graham Inlet and near the 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0

1 Racine River were nearly identical, with a strong thermocline Fork Length (mm) between 20 m and 24 m. Near Engineer, the thermocline was 800 weaker, but present between 15 m and 20 m, with a highly 700 defined thermocline in the main basin at 22 m. No

600 thermocline was present in Windy Arm, with steady ) o mm

( temperatures near 13 C throughout the water column. 500 h t

g Dissolved oxygen was constant in all locations. Overall Tagish n

e 400 L

k Lake was suitable for lake trout. r o F 300

200 Tagish Lake: Graham Tagish Lake: Engineer Tagish Lake: Main basin Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 0 5 10 15 100 0 5 10 15 0 0 0

0 10 10 10 0 5 10 15 20 25 30

Age (year) 20 20 20

30 30 30 ) ) ) m m m ( ( ( h h h t t t p p p e e e D D D 40 40 40

50 50 50

60 60 60 For more information, please contact Temperature Temperature Temperature Dissolved Oxygen Dissolved Oxygen Dissolved Oxygen 70 Department of Environment 70 70 Fish and Wildlife, Fisheries [email protected] 867-667-5652

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86 Fish and Wildlife Branch Fisheries Report

Tarfu Lake 2010 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters B The results from this survey suggest that this productive, small lake SURFACE AREA ELEVATION has a smaller density of lake trout. This agrees with findings from historic angler harvest surveys, which show low catch rates for lake 404 ha 773 m trout. Given the small population of lake trout, and in combination with the lakes popularity as a fishing destination, we suggest that MAXIMUM DEPTH AVERAGE DEPTH the lake trout population could be at risk of collapse. 33 m 11.6 m

SURFACE TEMPS. REGULATIONS Lake Whitefish Not available Special management There were no lake whitefish captured during this survey. Additional species sampled included: arctic grayling, northern pike SAMPLING DATES NET SETS and round whitefish. July 7-8, 2010 23 Recommendation Location We recommend a regulation change to prohibit lake trout retention Tarfu Lake is a small lake located for this lake. approximately 35 km southeast of Jakes Corner, along the Atlin Road. Tarfu Lake is within the Traditional Territory of the Carcross/ Program Overview Tagish First Nation and Taku River Tlingit First Nation. The Lake Trout Monitoring Program uses the Summer Profundal Access and Use Index Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Access to Tarfu Lake is from the Atlin Road. This lake has a popular government This program surveys the two species by placing gill nets campground and accessible boat ramp. throughout the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 87 Lake Trout Lake Whitefish

Overview Overview A total of eight lake trout were sampled during the 2010 During this survey, 96 lake whitefish were sampled. They survey. They ranged from 440 mm to 824 mm in fork length. ranged in fork length size from 220 mm to 470 m. Age Age strucutures were taken from four lake trout. Ages structures for lake whitefish were not obtained in 2010. ranged from 11 to 45 years. However, given the numbers sampled and their size, we suspect that this population is healthy. Population Estimate / Density The lake trout population estimate for Tarfu Lake was680 (estimate range 52 – 1,319). This equates to a density of 1.7 lake trout per hectare, which is less than predicted for a small productive lake. There is uncertainty in this population Temperature and Oxygen estimate due to the small number of lake trout sampled. Temperature and oxygen profiles were not assessed during the 2010 survey as this equipment was not available.

0.2 y c n e u q e r F 0.1 t n e c r e P

Fork Length (mm)

900

800

700

600 )

mm 500 ( h t

g 400 n e L k

r 300 o F 200

100

0 0 10 20 30 40 50 Age

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

88 Fish and Wildlife Branch Fisheries Report

Ta’tla Mun 2011 Lake Trout Monitoring Program

Overall Status Lake Information Lake Trout WATERSHED LAKE CLASS Ta’tla Mun was found to have a healthy population of large-bodied Pelly D lake trout, as evidenced by the large numbers of lake trout sampled during our survey. This finding agrees with our past SURFACE AREA ELEVATION (1991) survey which also reported a healthy lake trout population. 3141 ha 525 m

MAXIMUM DEPTH AVERAGE DEPTH Lake Whitefish 48 m 27 m The lake whitefish population was found to be healthy. Additional species sampled included: burbot and northern pike. SURFACE TEMPS. REGULATIONS O 16.5 C Special management Recommendation SAMPLING DATES NET SETS The recommendation resulting from the 2011 survey is to use this July 5-8, 2011 63 data to guide the Ta’tla Mun Special Management Area plan. If this lake is to be resampled, we recommend increasing the number of net set and age structures obtained, which will aid our confidence Location in the population number and provide adequate information on Ta’tla Mun is located approximately 30 km population structure. southeast of Pelly Crossing. The lake is within the Traditional Territory of the Selkirk First Nation. This lake is of historical and cultural Program Overview significance and as such, has been designated asaSpecial Management Area. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout Access and Use and lake whitefish abundance, growth, age and density. There is no road access to the lake, however This program surveys the two species by placing gill nets there is a well-defined trail from Pelly throughout the lake, taking into account both location and depth. Crossing, accessible by off-road vehicles. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 89 Lake Trout Lake Whitefish

Overview Overview A total of 65 lake trout were captured during the 2011 A total of 632 lake whitefish were sampled during the 2011 survey, ranging from 320 mm to 870 mm in fork length. survey. Sampled lake whitfish fork length ranged from 220 Sampled fish had an average fork length of 671 mm and mm to 560 mm, with an average length of 335 mm and an average weight of 4,250 g. Age structures were obtained average weight of 538 g. Age structures were taken from 6 from 15 lake trout. Ages ranged from 12 to 34 years. fish. Ages ranged from 7 to 20 years.

Population Estimate / Density 0.14

The lake trout population estimate within Ta’tla Mun was 0.12 12,937 (estimate range: 7,570 – 18,515). This equates to a density of 4.1 lake trout per hectare. 0.1

0.08 y c n e u

0.09 q

e 0.06 r F t

0.08 n e c y r c 0.04 e n 0.07 P e u q e

r 0.06 0.02 F

0.05 0 0.04 Percent

0.03 Fork Length (mm)

0.02

0.01

0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 0 5 0 5 0 5 0 5 0 5 Temperature and Oxygen 6 6 3 3 4 4 5 5 7 7 8 8

Fork Length (mm) Temperature and dissolved oxygen profiles were taken in the deepest part of the lake. The lake was thermally stratified with the thermocline extending from the surface to about 13

900 m. Below this the temperature remained at 4ºC to the bottom. 800

700 Temperature (C), Dissolved Oxygen (mg/L) 600 0 5 10 15 20

) 0

mm 500 ( h t g

n 5

e 400 L k r o F 300 10

200 15 100 20 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 ) m ( Temperature

h 25

Age t p e D 30 Dissolved Oxygen

For more information, please contact 50 Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

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90 Fish and Wildlife Branch Fisheries Report

Ten Mile Lake 2016 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters B Survey results indicate that the lake trout population in Ten Mile Lake is SURFACE AREA ELEVATION small, and is vulnerable to collapse. However, our confidence in the population estimate is weak. The lake trout population is composed of 326 ha 808 m the large-bodied type. MAXIMUM DEPTH AVERAGE DEPTH 48 m 23 m Lake Whitefish The population of lake whitefish in Ten Mile Lake also appears small in SURFACE TEMPS. REGULATIONS number. 16.0OC Conservation Waters SAMPLING DATES NET SETS Recommendation June 27-29, 2017 26 The recommendation for future surveys of the Ten Mile Lake is to Location increase the number of net sets, while attempting to minimize mortalities. Increasing the number of sets will improve the precision of Ten Mile Lake is located approximately 110 km our population estimate. Angler Harvest surveys and collaboration with north of Whitehorse, along the North Klondike the outfitter will assist in determining recreational angling pressure and Highway. This lake is within the Traditional success. Territories of the Ta’an Kwäch’än Council, Kwanlin Dün First Nation and the Little Salmon/Carmacks First Nation. Program Overview

Access and Use The Lake Trout Monitoring Program uses the Summer Profundal Index Ten Mile lake is accessed by float plane or a Netting (SPIN) method to provide information on lake trout and lake 15km 4x4 access trail. There is a wilderness whitefish abundance, growth, age and density. outfitter operating on this lake. This program surveys the two species by placing gill nets throughout the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 91 Lake Trout Lake Whitefish

Overview Overview A total of 26 lake trout were sampled during this survey. During the 2016 survey, a total of 23 lake whitefish were These large-bodied lake trout ranged in fork length from 424 sampled. The size of these fish ranged from 397 mm to 515 mm to 597 mm. They had an average length of 503 mm with mm, with an average fork length of 475 mm and an average an average weight of 1,610 g . Age structures were obtained weight of 1,522 g. Age structures were obtained from 12 from nine lake trout. Ages ranged from 9 to 19 years. lake whitefish. Ages ranged from 5 to 28 years.

Population Estimate / Density 60% The population estimate for lake trout in Ten Mile Lake was 522 (estimate range: 1 -1,117). Given the variablity 50% associated with this population estimate, there is little 40% y c

confidence in this number. n e u q e r 30% F t

30% n e c r e

P 20%

25%

10%

20% y c

n 0% e 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 u 6 6 6 6 25 27 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97 0 q 1 e r

F 15% Fork Lenth (mm) t n e c r e P 10% Temperature and Oxygen

5% Temperature and dissolved oxygen profiles were obtained on June 27, 2016. The temperature profile shows a steep 0% 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 2 5 7 2 5 7 2 5 7 0 0 2 5 7 0 0 6 6 6 6 25 27 30 3 3 3 40 4 4 4 5 52 55 57 7 72 75 77 80 8 8 8 9 92 95 97

0 thermocline from 5 m to 10 m, followed by a gradual decline 1 Fork Lenth (mm) through the remaining water column. Dissolved oxygen displayed an increase in concentration from 5 m to 10 m, 700 followed by a gradual decline. Overall, optimum habitat for lake trout existed between 8 m and lake bottom. 600

500 Temperature (C), Dissolved Oxygen (mg/L) ) 0 5 10 15 20

mm 400 ( 0 h t g n

e 300 L k r o

F 10 200

100 20

0 )

0 5 10 15 20 m ( h

Age (year) t 30 e p D

For more information, please contact 60 Department of Environment Temperature Dissolved Oxygen Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

92 Fish and Wildlife Branch Fisheries Report

Teslin Lake 2016 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Yukon Headwaters F Lake Trout SURFACE AREA ELEVATION Survey results suggest that the lake trout population in Teslin Lake is small. Concerns over the health of this stock have been ongoing. Our 37,720 ha 684 m survey results indicated that this population is still recovering, however there is a large uncertainty with our population estimate, which makes MAXIMUM DEPTH AVERAGE DEPTH definitive judgements about this population difficult. 232 m 54 m

SURFACE TEMPS. REGULATIONS Lake Whitefish O 15.9 C Special Management Based on our low catch rates, the population of lake whitefish in Teslin SAMPLING DATES NET SETS lake appears small. Additional species sampled included: arctic grayling, northern pike, lease cisco, slimy sculpin, chinook salmon and chum July 18-22, 2016 135 salmon.

Location Recommendation Teslin Lake is a transboundary lake with The recommendation for future surveys of Teslin Lake, is to slightly British Columbia, located in southern Yukon, increase the number of net sets as well as increase the number of aging approximately 125 km east of Whitehorse. stucutres collected for analysis. Lakes of this size can be difficult to The community of Teslin, sits on the eastern establish precise population estimates. Increased analysis of age shore, along the Alaska Highway. This lake is structures will allow improved information on the population structure of within the Traditional Territories of the Taku lake trout within this lake. River Tlingit First Nation and the Teslin Tlingit Council. Program Overview Access and Use Teslin is accessed from numerous locations, The Lake Trout Monitoring Program uses the Summer Profundal Index within the community of Teslin and the Netting (SPIN) method to provide information on lake trout and lake government campground, both have whitefish abundance, growth, age and density. accessible boat ramps. There are also a This program surveys the two species by placing gill nets throughout number of private residences along the lake. the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the health of these species.

SR-20-02 93 Lake Trout Lake Whitefish

Overview Overview During the 2016 survey of Teslin Lake, a total of 59 lake During 2016 a total of 87 lake whitefish were captured. The trout were sampled. These large-bodied fish, ranged from lake whitefish sampled had an average fork length of 440 261 mm to 793 mm in fork length. They had an average mm and an average weight of 1,204 g. length of 500 mm and an average weight of 1,764 g. Age structures were obtained from 11 lake trout. Ages ranged 30 from 3 to 40 years. 25 y c n e

u 20 q e Population Estimate / Density r F t n

e 15 c

The population estimate for lake trout in Teslin Lake was r e 63,759 (estimate range: 7,558 -121,001). The survey results P 10 were uncertain, as evident by the wide range in the population estimate. This estimate equates to an average 5 density of 1.8 lake trout per hectare. 0 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7

Fork Length (mm) 16

y 12 c n

e Temperature and Oxygen u

q 10 e r F t

n 8 Temperature and dissolved oxygen profiles were taken on e c r e

P 6 July 27. The temperature profile displays a strong

4 thermocline between 6 m and 10 m, followed by a gradual

2 decline throughout the rest of the water column. The dissolved oxygen levels near the surface were high, followed 0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 by a decline to 10 m. Overall, habitat was suitable for lake 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0 1 trout from 10 m to 50 m. Fork Length (mm)

Temperature (C), Dissolved Oxygen (mg/L) 700 0 5 10 15 20 0 600

) 500 mm

( 10 h t 400 g n e L k r 300 o

F 20

200 ) m (

100 h

t 30 e p D 0 0 5 10 15 20 25 30 35 40 45 40 Age (year)

For more information, please contact 60 Department of Environment Temperature Dissolved Oxygen Fish and Wildlife, Fisheries [email protected] 867-667-5652

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94 Fish and Wildlife Branch Fisheries Report

Twin Lake (east) 2013 Lake Trout Monitoring Program

Lake Information Overall Status

Lake Trout WATERSHED LAKE CLASS The lake trout population in Twin Lake East appears small. This may be Yukon headwaters A due to a mix of available habitat, as well as recreational pressure. SURFACE AREA ELEVATION 61 ha 630 m Lake Whitefish

MAXIMUM DEPTH AVERAGE DEPTH We did not sample any lake whitefish in Twin Lake East during this survey. 34 m 14.6 m

SURFACE TEMPS. REGULATIONS Recommendation 21OC Special Management Although recreational angling effort on Twin Lake East was not formally SAMPLING DATES NET SETS at the time of this survey, prior surveys conducted on Twin Lake West, June 26-27, 2013 24 showed a moderate level of pressure. It can be inferred that due to the close proximity of this lake, the pressure may be the same. Location Twin Lake (east) lies along the North Klondike Highway, in central Yukon. This lake is within Program Overview the Traditional Territories of the Kwanlin Dün The Lake Trout Monitoring Program uses the Summer Profundal Index and Little Salmon/Carmacks First Nations. Netting (SPIN) method to provide information on lake trout and lake whitefish abundance, growth, age and density. Access and Use This program surveys the two species by placing gill nets throughout Twin Lake (east) is accessed from the Klondike the lake, taking into account both location and depth. Over time, this Highway, with a popular government type of sampling allows us to track population changes and evaluate the campground across this lake at Twin (west). health of these species. There is an accessible gravelled area that acts as a rough boat ramp.

SR-20-02 95 Lake Trout Lake Whitefish

Overview Overview During the 2013 Twin Lake (east) survey, a total of 20 lake During this survey, no lake whitefish were captured in Twin trout were sampled. The sampled lake trout ranged in fork Lake (east). length size from 325 mm to 672 mm. They had an average length of 529 mm and an average weight of 2,017 g. Age structures were only obtained from two individuals, both of which were 15 years of age.

Population Estimate / Density Temperature and Oxygen The population estimate of lake trout in Twin Lake (east) was 193 (estimate range: 94 – 296). This equates to a density of Temperature and dissolved oxygen profiles were taken on 3.2 lake trout per hectare. This density was slightly lower June 25, 2013, near the deepest section of Twin Lake (east). than expected. The lake was stratified with a thermocline between 4 m and 7 m. The dissolved oxygen was within suitable limits between the surface and 32 m. Overall habitat was suitable for lake trout between 4 m and 32 m. 25

20 Temperature (C), Dissolved Oxygen (mg/L) 0 5 10 15 20 25 0.0 15 y c n e u q

e 5.0 r 10 F t n e c r e

P 5 10.0

) 15.0 5 5 5 5 5 5 5 5 5 5 5 5 5 5 m 00 2 50 7 2 7 2 7 2 7 00 50 2 7 2 7 ( 6 6 6 6 300 3 350 3 400 4 450 4 500 5 550 5 7 72 7 77 800 8 850 8 900 9 950 9 h 1000 t p

Fork Length (mm) e D 20.0

25.0

30.0

35.0

For more information, please contact Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

96 Fish and Wildlife Branch Fisheries Report

Twin Lake (west) 2013 Lake Trout Monitoring Program

Overall Status Lake Information Lake Trout The lake trout population in Twin Lake (west) appears to be in a WATERSHED LAKE CLASS depleted state, when compared to lake trout populations in other Yukon Headwaters B similarly sized Yukon lakes. Low catch numbers create a situation where SURFACE AREA ELEVATION it is difficult to estimate population numbers with precision. However the low catch rate may also indicate that the population is at risk of 153 ha 630 m collapse. MAXIMUM DEPTH AVERAGE DEPTH 43 m 16.1 m Lake Whitefish The lake whitefish population in Twin Lake (west) appears small and SURFACE TEMPS. REGULATIONS O lower than predicted, when compared to other Yukon lakes of similar 20.7 C Special Management size. SAMPLING DATES NET SETS June 25-26, 2013 26 Recommendation Twin Lake (west) receives a high level of angling pressure and due to Location habitat limitations, appears to have a small lake trout population. In Twin Lake (west) lies along the North Klondike combination, this makes the population vulnerable to collapse. It is the Highway, in central Yukon. This lake is within recommended that a regulation is established that eliminates the catch the Traditional Territories of the Kwanlin Dün, and possession of lake trout. This will aide in allowing this population to Champagne/Aishihik and Little Salmon/ naturally recover. Carmacks First Nations.

Access and Use Program Overview Twin Lake (west) is accesed from the Klondike The Lake Trout Monitoring Program uses the Summer Profundal Index Highway, with a popular government Netting (SPIN) method to provide information on lake trout and lake campground at the lake. There is an accessible whitefish abundance, growth, age and density. boat ramp at this campground. This program surveys the two species by placing gill nets throughout the lake, taking into account both location and depth. Over time, this type of sampling allows us to track population changes and evaluate the SR-20-02 health of these species. 97 Lake Trout Lake Whitefish

Overview Overview During the 2013 Twin Lake (west) survey, only seven lake During this survey, 26 lake whitefish were sampled. The trout were sampled. Lake trout ranged in fork length size sampled lake whitefish ranged from 252 mm to 530 mm in from 230 mm to 618 mm. They had an average length of fork length, with an average length of 432 mm and average 432 mm and an average weight of 1,125 g. Age structures weight 1,021 g. Age structures were obtained 13 lake were obtained from three individuals. The ages of these whitefish. Ages ranged from 5 to 25 years. The low catch sampled fish were 7, 11 and 29. numbers create difficulty in making definitive conclusions about this population.

Population Estimate / Density 35 The population estimate of lake trout in Twin Lake (west) 30

was234 (estimate range: 0 – 474). This equates to a y 25 c n e

density of 1.5 lake trout per hectare. Given the lack of u q 20 e r F

precision associated with this estimate and the potential for t n

e 15 c r collapse, a cautionary approach to managment regulations is e P warranted. 10

35 0 300 325 350 375 400 425 450 475 500 525 550 575 600 625 650 675 700 30 Fork Length (mm) 25 y c

n 20

e Temperature and Oxygen u q e r

F 15 t

n Temperature and dissolved oxygen profiles were taken on e c r

e 10

P June 25, near the deepest section of Twin Lake (west). The lake was stratified with an observed thermocline between 4 5 and 7 m. The dissolved oxygen was within suitable limits 0 between the surface to 32 m. Overall, suitable lake trout 300 325 350 375 400 425 450 475 500 525 550 575 600 625 650 675 700 habitat could be found between 4 m and 32 m. Fork Length (mm)

Temperature (C), Dissolved Oxygen (mg/L) 700 0 5 10 15 20 25 0 600

) 500 5 mm ( h t 400 g n 10 e L k r 300 o F 15 200 Temperature ) m ( Dissolved Oxygen

100 h t 20 p e D 0 0 5 10 15 20 25 30 35 25 Age (year)

35 For more information, please contact 40 Department of Environment Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

98 Fish and Wildlife Branch Fisheries Report

Wolf Lake 2018 Lake Trout Monitoring Program

Lake Information Overall Status

WATERSHED LAKE CLASS Lake Trout Yukon Headwaters E In accordance with the 2018 survey results, the lake trout population in SURFACE AREA ELEVATION Wolf Lake appears healthy. This population is of the large-bodied form. The population estimate indicates a moderate density of lake trout when 7,312 ha 986 m compared to similar sized Yukon lakes. MAXIMUM DEPTH AVERAGE DEPTH 72 m 26.6 m Lake Whitefish The population of lake whitefish in Wolf Lake is low in density, as SURFACE TEMPS. REGULATIONS evidenced by the low catch-numbers. 16OC Conservation waters SAMPLING DATES NET SETS Recommendation Aug 02-05, 2018 98 The recommendation for future surveys of Wolf Lake is to slightly increase net sets and age structures, to improve our precision in the Location population estimate. Wolf Lake is located in the Southern Lakes region, approximately 70km northeast of Teslin, and is within the Traditional Territory of Program Overview the Teslin Tlingit Council. The Lake Trout Monitoring Program uses the Summer Profundal Index Netting (SPIN) method to provide information on lake trout and lake Access and Use whitefish abundance, growth, age and density. Wolf Lake is only accessible by plane and This program surveys the two species by placing gill nets throughout receives minimal fishing pressure. A fishing the lake, taking into account both location and depth. Over time, this lodge has been established on the lake since type of sampling allows us to track population changes and evaluate the 1978, and operates on a catch and release health of these species. policy.

SR-20-02 99 Lake Trout Lake Whitefish

Overview Overview A total of 81 lake trout were sampled during the survey. During the 2018 survey, a total of 13 lake whitefish were These large-bodied lake trout ranged in fork length from 262 sampled. The fork length of these fish ranged from 515 mm mm to 860 mm. They had an average length of 547 mm with to 575 mm. They had an average length of 548 mm and an an average weight of 2,091g. Age structures were obtained average weight of 2,505 g. Age structures were taken from from 35 lake trout. Ages ranged from 5 to 40 years. nine lake whitefish. Ages ranged from 12 to 40 years. Population Estimate / Density 60 The population estimate for lake trout in Wolf Lake was 50 y

28,411 (estimate range: 16,103 - 41,243). This equates to a c n e u density of 3.9 lake trout per hectare. q 40 e r F t n

e 30 c r e

25 P 20

20 10 y c n e u

q 0 e 15 r 0 5 0 5 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 F 0 2 5 7 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 t 6 6 6 6 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5 7 n e c r

e 10 Fork Length (mm) P

0 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 0 0 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 0 2 5 7 Temperature and Oxygen 6 6 6 6 3 3 3 3 4 4 4 4 5 5 5 5 7 7 7 7 8 8 8 8 9 9 9 9 0 1

Fork Length (mm) Temperature and dissolved oxygen profiles display a sharp thermocline between 5 m and 9 m, below the thermocline which had a gradual temperature decline occurred. Dissolved oxygen remained relatively constant throughout the water 900 column. Overall, optimum lake trout habitat existed from 6 m 800 to lake bottom.

700 )

mm 600 Temperature (C), Dissolved Oxygen (mg/L) ( h

t 0 5 10 15 20 g 500 n 0 e L k

r 400 o F

300 10

200

100 20

0 0 5 10 15 20 25 30 35 40 45 Temperature

Age (year) ) 30 m

( Dissolved h t Oxygen p e

D 40

For more information, please contact 60 Department of Environment 70 Fish and Wildlife, Fisheries [email protected] 867-667-5652

SR-20-02 Table of Contents

100 Journal of Fisheries and Aquatic Sciences, 37(2), pp.255-267. References Jessup, L.G., and N. Millar. 2001. Application of a new method for monitoring lake trout abundance in Yukon: Summer Profundal Index Netting Barker, O.E., N.P. Millar and A. Foos. 2014. Lake (SPIN). Yukon Fish and Wildlife Branch Report. Trout and Lake Whitefish Population TR-11-11. Whitehorse, Yukon, Canada. Assessment: Kluane Lake 2013. Yukon Fish and Kennedy, W.A., 1953. Growth, maturity, fecundity Wildlife Branch Report TR-14-04, Whitehorse, and mortality in the relatively unexploited Yukon, Canada. whitefish, Coregonus clupeaformis, of Great Beker, G. 1983. Fishes of Wisconsin. The University Slave Lake. Journal of the Fisheries Board of of Wisconsin Press, Madison, Wisconsin. Canada, 10(7), pp.413-441. Carl, L.M. 2007. Lake trout demographics in relation Lindsey, C.C. 1964. Problems in zoogeography of the to burbot and coregone populations in the lake trout, Salvelinus namaycush. Journal of the Algonquin Highlands, Ontario. Environmental Fisheries Research Board of Canada 21(5): 977- Biology of Fishes 83(2): 127-138. 994. Christie, G. C., and H. A. Regier. 1988. Measures of Mackenzie-Grieve, J.L., and J.R. Post. 2006a. optimal thermal habitat and their relationship to Projected impacts of climate warming on yields for four commercial fish species. Canadian production of lake trout (Salvelinus namaycush) Journal of Fisheries and Aquatic Sciences 45: in Southern Yukon lakes. Canadian Journal of 301-314. Fisheries and Aquatic Sciences. 63:788-797. Clark, B.J., P.J. Dillon and L.A. Molot. 2004. Lake Mackenzie-Grieve, J.L., and J.R. Post. 2006b. Thermal Trout (Salvelinus namaycush) habitat volumes habitat use by lake trout in two contrasting and boundaries in Canadian Shield Lakes. Yukon lakes. Transactions of the American Chapter 6 in Boreal Watersheds: Lake Trout Fisheries Society. 135:727-738. Ecosystems in a Changing Environment. J.M. Martin, N.V. and C.H. Oliver. 1980. The Lake Charr, Gunn, R.J. Steedman and R.A. Ryder, Editors. Salvelinus namaycush, pp.205-272. W.E.K. Lewis Publishing, Boca Raton, Florida. Baron (ED), Chars, Salmonid fishes of the genus Environment Yukon. 2010. Status of Yuko Fisheries salvelinus. W.Junk, The Hague. 2010: An overview of the state of Yukon Mee, J.A., Bernatchez, L., Reist, J.D., Rogers, S.M. and Fisheries and the health of fish stocks, with Taylor, E.B., 2015. Identifying designatable units special reference to fisheries management for intraspecific conservation prioritization: a programs. Yukon Fish and Wildlife Branch hierarchical approach applied to the lake Report MR-10-01. Whitehorse, Yukon, Canada. whitefish species complex (C oregonus Evans, D.O. 2995. Effects of Hypoxia on scope-for- spp.). Evolutionary Applications, 8(5), pp.423- activity of lake trout: Defining a new dissolved 441. oxygen criteria for protection of lake trout McPhail, J.D. 2007. The Freshwater Fishes of British habitat. Technical Report 2005-01. Habitat and Columbia. University of Alberta Press. Fisheries Unit, Aquatic Research and Edmonton, Alberta. 620p. Development Section. Ontario Ministry of Natural Milligan, H.E. 2018. Lake productivity and Resources, Peterborough, Ontario. sustainable fish harvest estimates: method Fisheries and Oceans Canada. 2019. Economic and review (MR-18-04). Government of Yukon, Commercial Analysis: 2015 survey of Whitehorse, Yukon, Canada. recreational fishing in Canada. Ottawa. Sandstrom, S.J., and N. Lester. 2009. Summer Havens, S., M. Lorne, P. Blanchfeld, M. Paterson and Profundal Index Netting Protocol; A Lake Trout S, Higgins. 2014. Evaluation of eutrophication Assessment Tool. Ontario Ministry of Natural and water level drawdown on lake whitefish Resources, Peterborough, Ontario. Version (Coregonus clupeaformis) productivity; Fish 2009.1. 22p + appendices. habitat assessment. Canadian Technical Report Schelsinger, D.C., and H.A. Reiger. 1982 Climatic of Fisheries and Aquatic Sciences No. 3110. Vi. + and morphometric indices of fish yields from 40P. natural lakes, Transactions of the American Healey, M.C., 1980. Growth and recruitment in Fisheries Society 111:114-150. experimentally exploited lake whitefish Scott, W.B. and E.J. Crossman. 1973. Freshwater Fishes (Coregonus clupeaformis) populations. Canadian of Canada. Bulletin of the Fisheries Research Board of Canada 184, 966p.

Lake Trout Monitoring Program: 2019 Program Update 101