Population Status & Ecology of Lake Sturgeon in Lake Michigan Tributaries
Carl R. Ruetz III Annis Water Resources Institute Grand Valley State University [email protected] Acknowledgements • Collaborators: Matt Altenritter, Kregg Smith (DNRE), Alex Wieten & Elizabeth Binoniemi- Smith (Gun Lake Tribe) • Travis Ellens, Billy Keiper, & Jessica Comben • Kurt Thompson for assistance with ArcGIS • Brendan Earl (URS Corp.) • John Gulvas & Leo Torvinen (Consumers Energy) • Funding: Consumers Energy, Michigan Department of Natural Resources & Environment, U.S. Fish & Wildlife Service The Lake Sturgeon (Acipenser fulvescens)
• Native to North America • Historical distribution – Great Lakes –Hudson Bay – Mississippi River – St. Lawrence River • Current range – 1% of historic Life History
• Delayed maturity – Males: 14-16 years – Females: 24-27 years • Frequency of spawning – Males: 1-2 years – Females: 3-7 years • Spawn in rivers • Sex specific timing Threats & Causes of Decline
• Overharvest – By-catch in commercial fishing –Caviar • Habitat degradation – Logging • Barriers – Construction of dams Overall Goals
• Determine population status of lake sturgeon in Lake Michigan tributaries –Muskegon, Grand, & Kalamazoo rivers • Examine juvenile ecology Adult Sampling (Spring)
• Gill netting: Muskegon Lake • Boat electrofishing: Muskegon River Adult Sampling (Spring) Muskegon Lake
Gill Netting Boat electrofishing Effort Effort Year Catch (hrs) Catch (hrs) 2008 1 458 7 24 2009 13 488 18 31 2010 8 984 10 14 Larval Drift Sampling Muskegon River
• Downstream of spawning site • 4 D-frame drift nets • Nets fished at night • Larval lake sturgeon measured & released Muskegon River: 2009
Water Temperature Captured Observed No Larvae Captured 22 Sturgeon Larvae Captured 22 20 20 18 18 16 16 14 14 12 12 10 10 8 8
Water Temperature 6 6 4 4 2 2 0 0
4/18/09 5/2/09 5/16/09 5/30/09 6/13/09 6/27/09 and Observed Captured Number of Lake Sturgeon Date Larval Drift: Muskegon River Year Catch Effort (hours) 2008 0 263 2009 32 194 2010 16 525 Grand River
Juvenile Sampling Muskegon Lake
• August-November • 23 juveniles captured (2008-2010) –14 received transmitters –10 extensively tracked + 3 current • 5 cohorts (Ages 0, 1, 2, 4, 7)*
Distribution in Muskegon Lake
30 28 Before Turnover After Turnover 26 24 22 20 18 16 14
Frequency 12 10 8 6 4 2 0 5 .5 5 .5 -0.5 1. -3.0 -3.5 4. -6.0 0 .0- 5 0 .0- 5 0.5-1.01 1.5-2.02.0-2 2. 3. 3.5-4.04 4.5-5.05.0-5 5. 6.0-6.5
Distance from River Mouth (km) Before Turnover During Turnover After Turnover Before vs. After Turnover
t= 7.27 25 df= 4 p= 0.001
20
15
10 Water Depth (m)
5
0 BT AT Monthly Movement Rate
0.6 F3,22= 1.26 p= 0.312
0.5
0.4
0.3
0.2 Movement Rate (km/d) Movement 0.1
0.0 August September October November Grand River Sampling Locations Juvenile Movements Grand River Habitat Mapping
N
Grand_sidescan_utm16.shp Grand_river_utm16.shp Grand_dt4_tracks.shp Conclusions • Muskegon Lake = important nursery area – Multiple cohorts – Residency – Suitable overwintering areas? • Adults (<100 annually) successfully reproduce in Muskegon River – Larvae & Age-0 lake sturgeon