Importance of Protecting Lake Trout

250,000 lakes in Ontario 1% of these contain lake trout Central/eastern Ontario has >1/3 of lakes Provincial responsibility to preserve Why Protect Lake Trout Waters?

 Represents 20-25% of world’s supply  Largest area of lake trout waters  Ontario has greatest responsibility in world

Lake Trout requirements =

Phosphorous Affects Oxygen =

Lake Trout Lake Protection  Province is committed to protecting fish habitat  Cooperative effort with municipalities  Provincial Policy Statement  Official Plan is the planning tool

Why Protect Lake Trout?  Native only to North America  Native stocks found on Canadian Shield  Isolated 10,000 years ago  Lake trout stocks genetically dissimilar  Once lost, no way to replace it  Keystone species, indicator of ecosystem health

Lake Trout Life History Lake Trout Life History  Need deep, well oxygenated, cold water lake environments to thrive –Late summer critical  Slow growing, late maturing, low productive potential

Lake Trout vs Walleye lake troutwalleye Fall spawn, 3-5 month incubation Females age-6 to 7 Produce eggs per kg 26 cm fish approx. age-4 Preferred water temperature: C Spring spawn, day incubation Females age-3 to 4 Produce 6000 – 7500 eggs per kg 26 cm fish approx. age-1 Preferred water temperature: C

Human Stressors

Mean Volume Weighted Hypolimnetic Dissolved Oxygen (MVWHDO)  Criterion developed by Dr. David Evans in 1993  Activity levels of lake trout limited by concentration of oxygen in water –Reduced oxygen affects swimming ability, feeding, avoidance of predators, growth and survival –Juveniles more sensitive  At temperatures of 4-14C, oxygen concentrations of 4.4, 5.8 and 7.1 mg/L limit activity to ¼, ½ and ¾, respectively  7 mg/L provide for most daily life support activities

Additional Supportive Data  Independent surveys of lake trout populations in southern Ontario: –Lake trout populations good to excellent when MVWHDO 7-8 mg/L –Recruitment average to poor when MVWHDO < 6 mg/L

The Lake Trout Policy  Policy proposal using MVWHDO (7.0 mg/L) posted on Environmental Bill of Rights Registry (EBR) for public comment in early 2006  EBR decision notice posted May 29, 2006  Lake trout lakes listed in ‘Inland Ontario Lakes Designated for Lake Trout Management’ available at:  Revisions will require posting on EBR Registry for public comment  Policy implemented Province-wide

Historical MVWHDO For Buck Lake Recommended concentration of 7 mg/L South Basin  Sept. 19, 1978 – 7.87 mg/L  Sept. 01, 1987 – 5.27 mg/L  Sept. 06, 2007 – 5.91 mg/L North Basin  Sept. 06, 2007 – 4.75 mg/L

Buck Lake Stocking History  three walleye stocking episodes between 1935 & 1948 (100,000 to 250,000)  11 smallmouth bass stocking episodes between 1935 & 1956  1 st record of lake trout stocking in 1949 with stocking each year between 1959 & 1989, average 4,000 annually  6,000 genetically marked lake trout stocked in 1991 & 1992

Historical Fish Assessment

1992 Buck Lake SLIN Catch (total no. fish)

1992 Buck Lake SLIN  0.6 lake trout per net  32 clipped lake trout (70%)  Mean total length: 39.7 cm (15.6 in)  Mean fork length: 35.8 cm (14.1 in)  Mean weight: 553 gms (1.2 lbs)

1997 Buck Lake SLIN  1997, Spring Littoral Index Netting (SLIN) –Short sets (30 minutes), small mesh (1.5”,2.0” and 2.5”) –Spring, ice out until surface temperature reaches 13C  May 6-23 –Set 59 nets at randomly selected sites

1997 Buck Lake SLIN  0.44 lake trout per net  17 clipped (65%)  Mean age: 6.6 yrs  Mean total length: 44.3cm (17.4 in)  Mean fork length : 40.9cm (16.1 in)  Mean weight: 875 gms (1.9 lbs)

1997 Buck Lake SLIN – lake trout age at size

Summer Profundal Index Netting (SPIN) Summer Profundal Index Netting (SPIN)  Season: mid-July to mid-September –Before thermocline collapses  Set duration: 2 hours  Net length: 64 m (210 ft) with 8 mesh sizes  Depth ranges: m; 20-30m; 30-40m  > 3 mg/L dissolved oxygen

SPIN Objectives 1.Obtain point-in-time estimate of relative area weighted density of lake trout (>300mm) 2.Obtain representative sample of lake trout population for diagnostic assessment of biological integrity

2007 Buck Lake SPIN  39 net sets, 365 ha sampled (682 ha total)  Total 41 lake trout caught >300 mm  Estimated density of 3.4 lake trout >300 mm per ha  Population estimate of 1,233 lake trout  Confidence limits: 465 to 2,021 lake trout (68% predicted level)  Mean length total catch: 35.4 cm (13.9 in)

2007 Buck Lake SPIN – Lake Trout Lengths

Buck vs Loughborough Lake SPINS BuckLoughborough No. net sets 3928 Total catch LT 4124 Est. density LT Conf. limits 465 – 2,021 0 – 3,237 Mean length 35.4 cm 40.8 cm

What can Buck Lake Landowners Do? 1.Work with municipality (Official Plan) & fellow land owners to support protection & enhancement of lake trout habitat 2.Work with fellow land owners to reduce nutrient inputs 3.Water level manipulation? 4.Creel survey – what’s coming out? 5.Assessment of other fish species?

Perfect ending to a day on the lake