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Yukon Freshwater Fisheries

Presentation to YFWMB

April 2014Nathan Millar

Senior Fisheries Biologist

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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.

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Today

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

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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 ( )

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Status of populationsHow 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.

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

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Lake/FisheryLake Size

(ha) YearEstimated

Hours Hours/ha. Lake/FisheryLake Size

(ha) YearEstimated

Hours Hours/ha.Jackson 65 2011 757 11.65 Kusawa Lake 14200 2006 4325 0.30Twin (West) Lake 160 2013 1543 9.64 Simpson Lake 2030 2002 608 0.30Tarfu Lake 405 2010 3141 7.76 Dezadeash Lake 8250 2013 2429 0.29Snafu Lake 651 2010 3783 5.81 Quiet Lake 5441 2011 1204 0.22Caribou Lake 32 1996 115 3.61 Tagish Lake 35460 2003 6888 0.19Frenchman Lake 1441 2012 4564 3.17 Teslin Lake 35400 2008 6812 0.19Fox Lake 1660 2013 5009 3.02 Aishihik Lake 14500 2006 2456 0.17Pine Lake 548 2009 1185 2.16 Frances Lake 9941 2009 1592 0.16Watson Lake 1320 2002 2543 1.93 Bennett Lake 9680 2009 1020 0.11Fish Lake 1320 2010 2376 1.80 Kluane Lake 39275 2004 2024 0.05Tatchun Lake 654 2005 750 1.15 Tagish Bridge 2007 2420Little Atlin Lake 4033 2008 4175 1.04 Johnson's Crossing - Spring 2001 322Kathleen Lake 3376 2004 2265 0.67 Kathleen River 2004 3757Braeburn Lake 558 2001 299 0.54 Lubbock River - Spring 2010 454Ethel Lake 4610 2012 2271 0.49 McIntyre Creek 2004 3190Laberge Lake 20100 2007 6706 0.33 Nares River 2009 2041Marsh Lake 9630 2007 3174 0.33

33 fisheries where we have monitored harvest

Harvest is sustainable

Harvest is increasingly unsustainable? ? ?

Status of lake trout500 – 1000 lakes that contain lake troutPopulation assessments done on 115Angler harvest surveys on 35 Most heavily fished populations

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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

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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?

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Beauty of surroundings

Quality of water

Escape routine

Access to wilderness

Privacy (from other anglers)

Weather conditions

Angling for wild fish

Number of fish caught

Catch desired species

Size of fish caught

Catch as a source of food

0 5 10 15

Ranking of Responses1 Environment beauty, water quality, wilderness2 Fish related size, number, etc.)3 Fishing environment not crowded4 Getting there cost, ease of access5 Socio-cultural enjoyment, family, relax6 sport challenge, excitement

Rec. Fish Survey1985

What most contributes to your enjoyment of sport fishing in Yukon?

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Lack of Pollutants in Fish

Lack of Angler Crowding

Absence of Other Recreationists

Presence of Wildlife

Size of Fish

Variety of Species Available

Cost

Catch Rate of Fish You Can Keep

Chance to Catch a Trophy Fish

Tourist Facility Quality

Access to Other Recreational Facilities

Availability of Handicapped Facilities

0 1 2 3 4 5Ranking of Responses

Rec. Fish Survey1990 and 1995

Factors that play a role in determining where to fish

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To Enjoy Nature

To Get Away

Family Togetherness

For Companionship

For A Sense of Achievement

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Ranking of Responses

Rec. Fish Survey1990 and 1995

Why anglers fish

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Uncrowded sites

Lots of fish

Ease of access

Remoteness

Large fish

0 10 20 30 40

Ranking of ResponsesRec. Fish Survey2010

What is most important to your angling experience

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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

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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

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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?

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What can we do?Wild Populations Enhanced Populations

Proactive regulations Yes Yes

Responsive Regulations Yes Yes

Stock Restoration Yes

Stock Enhancement Yes

Physical Habitat Restoration / Enhancement

Yes Yes

Chemical Habitat Restoration / Enhancement

? Yes

Manipulation of Other Species

? Yes

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Question

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

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Definitions

RestorationReturning a population (or habitat) to a natural level

EnhancementMoving a population (or habitat) beyond a natural level

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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?

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

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Productivity in lakes

• Temperature• Sunlight

– Effect of ice• Nutrients – phosphorus

and nitrogen• Geology

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Experimental Lakes AreaLake 226

Phosphorus

Eutrophication

http://www.experimentallakesarea.ca/images/Eutrophication.pdf

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Productivity across the landscape

Productivity is lowLimited by phosphorus and nitrogenOligotrophic and mesotrophic

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Fish Habitat

Fish Passage & habitat fragmentation:culverts

Installed correctly

Flood scourspool

Repeated floods= barrier

Very expensiveto fix

Mike Sullivan

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Fragmentation

Athabasca River, near Hinton Craig Johnson (ACA)

95% of watershedlost

2 species above8 species below

Baseline Creek watershed

Mike Sullivan

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Question

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

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Fish Ecology

• Competition• Predation

Question:What do lake trout eat?

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What lake trout eat in Yukon

Unidentified Fish Non-Biting Midges CaddisfliesScuds, Sideswimmers Unidentified Inver-

tebratesLeast Cisco

Pond Snails Unknown Orb SnailsBeetles Unidentified Vegetation Clams, MusselsWater Mites Slimy Sculpin AntsRound Whitefish Water Fleas

1000 stomachs

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round whitefishlake chub

burbot

lake trout

lake whitefish

sculpinGammarus (Amphipods / sideswimmer)

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Snails (gastropod)

Copepod(planktonic)

Clams

Midges(Chironomids)

Water mites

Caddisfly(Tricopteran)

Dragonfly(Odonata)

Juvenilelake trout

Daphnia

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What lake whitefish eat in YukonOrb SnailsCopepodsClams, MusselsNon-Biting MidgesSnailsScuds, SideswimmersUnknownPond SnailsUnidentified InvertebratesCaddisfliesLeechesWater MitesDragonflies, DamselfliesUnidentified Vegetation

400 stomachs

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round whitefishlake chub

burbot

lake trout

lake whitefish

sculpinGammarus (Amphipods / sideswimmer)

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Snails (gastropod)

Copepod(planktonic)

Clams

Midges(Chironomids)

Water mites

Caddisfly(Tricopteran)

Dragonfly(Odonata)

Juvenilelake trout

Daphnia

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Fish eat different things are different times of their lives: ontogenetic shift

• Juvenile Lake Trout– Eat benthos– Suboptimal habitats

• Adult Lake Trout– Eat fish

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1. Egg Predation

Eggs that don’t descendhave low survival anyway

No literature confirmation

1. Juvenile Predation

The frying pan or the fire

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lake trout

lake whitefish

sculpinGammarus (Amphipods / sideswimmer)

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Snails (gastropod)

Copepod(planktonic)

Clams

Midges(Chironomids)

Caddisfly(Tricopteran)

Dragonfly(Odonata)

Daphnia

3. Competition

N = 777

Small bodiedEat invertebratesNever get very bigTend to be in smaller lakesLakes don’t have lake whitefish

Large bodiedEat fishKeep growingTend to be in larger lakesLakes have lake whitefish

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Others

• Burbot – predatory and opportunistic– Also a sport fish

• Round whitefish – opportunistic egg predators

Summary

Many northern fish are generalist feeders

CaveatsLimitations on diet analysis – ‘point in time’, variation between fish, some items more digestible.Other techniques – stable isotopes of carbon and nitrogen provide time averaged

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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

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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.

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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?

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20 Stocked Lakes8% of all fishing

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Some issues with stocking open systems

• Genetics – do you stock the same species?• Competition • Disease • Cost – initial, ongoing, monitoring• Unintended consequences

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A lake trout (mis)introduction

• Yellowstone Lake• 1994 – Lake trout were

first found– “bucket biology”

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 suppressionActive netting