Yukon Freshwater Fisheries Presentation to YFWMB

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

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.

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

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 ( )

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.

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

9. 33 fisheries where we have monitored harvest

10. 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 ? ? ? Harvest is increasingly unsustainable Harvest is sustainable

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

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?

13. Rec. Fish Survey 1985 What most contributes to your enjoyment of sport fishing inYukon?

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

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

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

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

18. Yukon Angler Psychographics 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 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 The Holiday Seeker -fishes as part of an outing or other activity -some are campground users The Trophy Seeker -wants to catch large fish -typically an experienced angler -possible gear intensive The Experience/Sport Seeker -wants to catch a lot of fish -practices live release -typically an experienced angler

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?

20. What can we do?

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

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

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

24. http://www.sage.wisc.edu/atlas/maps/npp/atl_npp.jpg

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

26. Experimental Lakes Area Lake 226 Phosphorus Eutrophication http://www.experimentallakesarea.ca/images/Eutrophication.pdf

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

29. Fish Habitat

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

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

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

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

34. What lake trout eat in Yukon 1000 stomachs

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

36. What lake whitefish eat in Yukon 400 stomachs

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

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

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

40. 1. Juvenile Predation The frying pan or the fire

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

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

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

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

46. References • Lasenby, T.A., S.J. Kerr, and G.W. Hooper. 2001. 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. 1999. Diet overlap between burbot and whitefish in a subarctic lake. Ann. Zool. Fennici 36: 205-214. • Beauchamp, D.A., M.W. Kershner, N.C. Overnman, J. Rhydderch, J. Lin, and L. Hauser. 2006. 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. 2008. Lake trout demographics in relation to burbot and coregonine populations in Algonquin Highlands, Ontario. Envrionmental Biology of Fish 83: 127-138. • Fitzimons, J.D. 1996. 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: 142-151 (Suppl). • Hulsman, M.F. 2012. 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. 2001. Lake trout stocking in inland lakes: and annotated bibliography and literature review. Ontario Ministry of Natural Resources.

47. Stocking • Restoration / Enhancement • Divert Pressure • Yukon • Pothole lakes – no outflow • No stocking of open systems • Limited supply of pothole lakes • Previously fishless lakes 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

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

50. A lake trout (mis)introduction • Yellowstone Lake • 1994 – Lake trout were first found • “bucket biology” Native Cutthroat Trout Solution – Lake trout suppression Active netting 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 Netting out the lake trout