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1. 2 Yukon Freshwater Fisheries Presentation to YFWMB April 2014 Nathan Millar Senior Fisheries Biologist 3.

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Presentation on theme: "1. 2 Yukon Freshwater Fisheries Presentation to YFWMB April 2014 Nathan Millar Senior Fisheries Biologist 3."— Presentation transcript:

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3 Yukon Freshwater Fisheries Presentation to YFWMB April 2014 Nathan Millar Senior Fisheries Biologist 3

4 You asked 5.2 The Board further recommends the Department of Environment… determine what can be done to enhance populations over the long term; The Board has also requested a scientific presentation from the Department pertaining to the effects of harvesting fish species such as whitefish and burbot on the survival rates of young lake trout and lake trout eggs. 4

5 Today Impact of fishing: trends Status of populations What do anglers want? Options 5

6 Impact of fishing We encourage angling & stewardship ( ) Number of anglers is steady ( ) Amount of fishing is steady ( ) Fewer fish are harvested ( ) Technology has changed – boats, gear ( ) 6

7 Status of populations How many? 45,000 lakes >1 ha. (9,000 km2) 8,000 lakes >10 ha. 850 lakes > 100 ha. (e.g., Coal, Lacelle) 75 lakes > 100 ha. (e.g., Squanga) 10 lakes > 1000 ha. (e.g, Frances) We have surveyed 115. We focus on the ones that get heavily fished and visit them repeatedly. 7

8 Distribution of Angling Effort in Yukon Hours Hours / ha Fishing effort / impact is not distributed equally across Yukon Centred in Southern Lakes Effort determined by access

9 9 Lake/Fishery Lake Size (ha)Year Estimated HoursHours/ha.Lake/Fishery Lake Size (ha)Year Estimated HoursHours/ha. Jackson Kusawa Lake Twin (West) Lake Simpson Lake Tarfu Lake Dezadeash Lake Snafu Lake Quiet Lake Caribou Lake Tagish Lake Frenchman Lake Teslin Lake Fox Lake Aishihik Lake Pine Lake Frances Lake Watson Lake Bennett Lake Fish Lake Kluane Lake Tatchun Lake Tagish Bridge Little Atlin Lake Johnson's Crossing - Spring Kathleen Lake Kathleen River Braeburn Lake Lubbock River - Spring Ethel Lake McIntyre Creek Laberge Lake Nares River Marsh Lake fisheries where we have monitored harvest

10 Harvest is sustainable Harvest is increasingly unsustainable ?? ? Status of lake trout 500 – 1000 lakes that contain lake trout Population assessments done on 115 Angler harvest surveys on 35 Most heavily fished populations

11 Summary: status of populations > 1,000 lakes with fishable populations 115 have been surveyed Most activity takes place on 30 – 60 (?) waters We know the harvest at 33 In most cases: the harvest is sustainable Where harvest is unsustainable: we work with RRCs, you, and anglers to develop and implement solutions 11

12 What do anglers want? When you go angling, what is important to you? What do you think are the most important things to Yukoner anglers, as a whole? 12

13 13 1Environmentbeauty, water quality, wilderness 2Fish relatedsize, number, etc.) 3Fishing environmentnot crowded 4Getting therecost, ease of access 5Socio-culturalenjoyment, family, relax 6sportchallenge, excitement Rec. Fish Survey 1985 What most contributes to your enjoyment of sport fishing in Yukon?

14 14 Rec. Fish Survey 1990 and 1995 Factors that play a role in determining where to fish

15 15 Rec. Fish Survey 1990 and 1995 Why anglers fish

16 16 Rec. Fish Survey 2010 What is most important to your angling experience

17 Summary: what anglers want The natural environment, the fishing environment, socio- cultural aspects are the most important Fish-related characteristics, logistics, and sport are less important to most anglers When it does comes to the fish: – Wild fish (1) – Number of fish caught (2, 1) – The ‘right’ species (3, 1) – Size of fish / large / trophy (4, 2, 2, 2) – Catch a fish to eat (5, 1) – Variety (3) – Catch rate (4) The “Average” Angler doesn’t exist 17

18 18 The Nature Seeker -wants to get outside -some are good anglers, some aren’t -seeks appropriate setting The Dinner Seeker -wants to catch a fish to eat -doesn’t practice live release unless required -high frequency -fish close to home where possible The Experience/Sport Seeker -wants to catch a lot of fish -practices live release -typically an experienced angler The Trophy Seeker -wants to catch large fish -typically an experienced angler -possible gear intensive The Holiday Seeker -fishes as part of an outing or other activity -some are campground users The Family Experience Seeker -fishes as part of an outing or activity to get the family together -practices live release and keeps some fish -amenities often important -some are campground users Yukon Angler Psychographics

19 Questions Given that anglers want different experiences when fishing, what kind of a fishery (or fisheries) best meets these interests? Are some of these interests conflicting? What makes fishing in Yukon different from fishing elsewhere? 19

20 What can we do? 20 Wild PopulationsEnhanced Populations Proactive regulationsYes Responsive RegulationsYes Stock RestorationYes Stock EnhancementYes Physical Habitat Restoration / Enhancement Yes Chemical Habitat Restoration / Enhancement ?Yes Manipulation of Other Species ?Yes

21 Question Do you place a different value on a fish caught in a stocked lake and a wild caught fish? 21

22 Definitions Restoration Returning a population (or habitat) to a natural level Enhancement Moving a population (or habitat) beyond a natural level 22

23 Lake productivity Primary productivity – Production of organic matter – Primary – at the base All about energy flows Root of all productivity: sun – Photosynthesis 23 What are some of the environmental constraints to fish production that exist here?

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25 Productivity in lakes Temperature Sunlight – Effect of ice Nutrients – phosphorus and nitrogen Geology 25

26 26 Experimental Lakes Area Lake 226 Phosphorus Eutrophication

27 Productivity across the landscape 27 Productivity is low Limited by phosphorus and nitrogen Oligotrophic and mesotrophic

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29 Fish Habitat

30 Fish Passage & habitat fragmentation: culverts Installed correctly Flood scours pool Repeated floods = barrier Very expensive to fix Mike Sullivan

31 Fragmentation Athabasca River, near Hinton Craig Johnson (ACA) Craig Johnson (ACA) 95% of watershedlost 2 species above 8 species below Baseline Creek watershed Mike Sullivan

32 Question If you harvest a species it will help (or hinder) another species? 32

33 Fish Ecology Competition Predation Question: What do lake trout eat? 33

34 What lake trout eat in Yukon stomachs

35 35 round whitefish lake chub burbot lake trout lake whitefish sculpin Gammarus (Amphipods / sideswimmer) 35 Snails (gastropod) Copepod (planktonic) Clams Midges (Chironomids) Water mites Caddisfly (Tricopteran) Dragonfly (Odonata) Juvenile lake trout Daphnia

36 What lake whitefish eat in Yukon stomachs

37 37 round whitefish lake chub burbot lake trout lake whitefish sculpin Gammarus (Amphipods / sideswimmer) 37 Snails (gastropod) Copepod (planktonic) Clams Midges (Chironomids) Water mites Caddisfly (Tricopteran) Dragonfly (Odonata) Juvenile lake trout Daphnia

38 Fish eat different things are different times of their lives: ontogenetic shift Juvenile Lake Trout – Eat benthos – Suboptimal habitats Adult Lake Trout – Eat fish 38

39 39 1. Egg Predation Eggs that don’t descend have low survival anyway No literature confirmation

40 1. Juvenile Predation The frying pan or the fire

41 41 lake trout lake whitefish sculpin Gammarus (Amphipods / sideswimmer) 41 Snails (gastropod) Copepod (planktonic) Clams Midges (Chironomids) Caddisfly (Tricopteran) Dragonfly (Odonata) Daphnia 3. Competition

42 N = 777 Small bodied Eat invertebrates Never get very big Tend to be in smaller lakes Lakes don’t have lake whitefish Large bodied Eat fish Keep growing Tend to be in larger lakes Lakes have lake whitefish

43 Others Burbot – predatory and opportunistic – Also a sport fish Round whitefish – opportunistic egg predators 43

44 Summary Many northern fish are generalist feeders Caveats Limitations on diet analysis – ‘point in time’, variation between fish, some items more digestible. Other techniques – stable isotopes of carbon and nitrogen provide time averaged

45 Can you fish down predators and competitors Species interact but not in simple ways – Dietary overlaps (competition) – Predation – Interactions can be positive for juveniles and negative for adults (for example) There may be tradeoffs between – Species – Size v. number 45

46 References Lasenby, T.A., S.J. Kerr, and G.W. Hooper Lake whitefish culture and stocking: an annotated bibliography and literature review. Fish and Wildlife Branch, Ontario Ministry of Natural Resources. Peterborough, ON. Tolonen, A., J. Kjellman and J. Lappalainen Diet overlap between burbot and whitefish in a subarctic lake. Ann. Zool. Fennici 36: Beauchamp, D.A., M.W. Kershner, N.C. Overnman, J. Rhydderch, J. Lin, and L. Hauser Trophic interactions of nonnative lake trout and lake whitefish in the flathead lake food web. Reportted to the Confederated Salish-Kootenai Tribes. Carl, L.M Lake trout demographics in relation to burbot and coregonine populations in Algonquin Highlands, Ontario. Envrionmental Biology of Fish 83: Fitzimons, J.D The significant of man-made structures for lake trout spawning in the Great Lakes: are they a viable alternative to natural reefs?. Canadian Journal of Fisheries and Aquatic Sciences 53: (Suppl). Hulsman, M.F Influence of fish competitors on lake trout trophic ecology in sub- arctic lakes. M.Sc. Thesis. University of Alberta. Kerr, S.J. and T.A. Lasenby Lake trout stocking in inland lakes: and annotated bibliography and literature review. Ontario Ministry of Natural Resources. 46

47 Stocking Restoration / Enhancement Divert Pressure Yukon – Pothole lakes – no outflow – No stocking of open systems – Limited supply of pothole lakes – Previously fishless lakes 47 Have you noticed differences in fishing in a lake that was stocked for the first time and that same lake a decade later?

48 20 Stocked Lakes 8% of all fishing 48

49 Some issues with stocking open systems Genetics – do you stock the same species? Competition Disease Cost – initial, ongoing, monitoring Unintended consequences 49

50 A lake trout (mis)introduction Yellowstone Lake 1994 – Lake trout were first found – “bucket biology” 50 Native Cutthroat Trout Netting out the lake trout First 15 Years: 500,000 lake trout caught and eliminated 2011 and 2012: 525,000 lake trout caught and eliminated 2013: 172,000 in the first six weeks of the season Solution – Lake trout suppression Active netting


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