Michigan Fisheries: The Big Picture Presented by: Brian Gunderman Date: November 8, 2011 Fisheries Management Stocking - restore populations (sturgeon) - create fishing opportunities lack of spawning habitat - adjust predator:prey ratios
D. Kenyon Regulations - prevent overexploitation - prevent spread of undesirable species - enforce principles of fair chase - reduce hooking mortality Fisheries Management Habitat Improvement - habitat altered due to dams, dredging, historic
logging activity, erosion, shoreline armoring, etc. Fisheries Management Habitat Improvement - habitat altered due to dams, dredging, historic, logging activity, erosion, shoreline armoring, etc. Projects: dam removals bank stabilization tree drops Lake Michigan Fishery
Forage Base 2010 Acoustic (open water) survey (Warner et al. 2011) Good news:strong year class of alewife total biomass higher than in recent years Bad news: smelt and bloaters still low total biomass ~50% of average from 1992-2004 Bottom trawl survey (Bunnell et al. 2011) Bad news: total biomass low and similar to 2009 most abundant species = round goby Yale.edu
Lake Michigan Fishery ACOUSTIC BOTTOM TRAWL Rainbow smelt Rainbow smelt Bloater Ninespine
stickleback Deepwater sculpin Round goby Slimy sculpin Alewife Alewife
8% native Bloater 46% native Lake Michigan Fishery Chinook Salmon (Claramunt et al. 2010) Stocking levels reduced since 1998 Variable survival, fishing effort, & natural reproduction Natural reproduction average = 44%
Lake Michigan Fishery Little Manistee Weir Returns # Chinook salmon 40,000 30,000 20,000
10,000 0 1968 1978 1988 Year 1998
2008 Invasive Species Asian Carp Background Introduced to U.S. in 1970s Bighead Eat plankton Tolerant of cold water
Often found in large, turbid rivers Potential vectors Chicago waterway Intentional release Silver Asian Carp - Response Electrical barriers Fence construction Lawsuit to close locks
MI, OH, WI, MN, and PA Illegal to possess or transport any live Asian carp in MI $10,000 fine Research DNR mgmt plan Wisconsin Sea Grant Quagga Mussels Same genus (Dreissena) as zebra mussels
Native to Caspian Sea and tributaries Arrived in Lake Michigan around 1997 Can colonize hard and soft substrates Eat algae Quagga Mussels Rapidly expanded in Lake Michigan Average lake-wide biomass density increased by >800% from 2004 to 2007 (Bunnell et al. 2009) - fish biomass density declined by 71% Not limited to shallow water out to 400 ft
Biomass of mussels much lower in 2010 than in 2007 (Good News!) USFS Quagga Mussels How do quagga mussels affect aquatic ecosystems? 1. Eat algae less food for zooplankton less zooplankton for planktivorous fishes 2. Increase water clarity increased plant growth
3. Excrete pseudofeces decrease oxygen and pH increase pollutant concentrations 4. Colonize pipes, boats, docks, etc. expensive and time consuming Idaho Dept. of Agriculture Starry Stonewort Algae similar to Chara Native to Europe Found in Lake St. Clair in 1974 Spread to many inland lakes in last 15 years
Pullman & Crawford 2010 boats, trailers, waterfowl Proliferates rapidly Forms dense mats in water depths up to 27 ft michiganlakeinfo.com Pullman & Crawford 2010 NY Sea Grant Starry Stonewort
Starry Stonewort Effects on Aquatic Ecosystems 1. Reduces diversity of rooted aquatic plants 2. Competes with planktonic algae for nutrients increased water clarity 3. Destroys spawning habitat for bass and bluegills 4. Oxygen depletion fish kills 5. Interferes with navigation michiganlakeinfo.com
Starry Stonewort Control Options Mechanical harvesting Algaecides haircuts Other herbicides? timing important www.aquamog.com Drawdowns? www.prolakemgt.com
VHS Virus VHSv = viral hemorrhagic septicemia virus Pathogen that can cause major fish kills - especially dangerous in hatcheries Originally from maritime region of Canada Probably transported to Great Lakes in ballast water Since 2005, VHS found in Lake Erie, Detroit River, Lake St. Clair, Lake Huron, Lake Michigan (WI), and 2 inland lakes D. Kenyon
Wisconsin DNR VHS Virus What are the symptoms of VHS? widespread hemorrhages droopy eyelids Will the virus affect humans? No. The virus dies at human body temperatures. How does the disease spread between waters? moving infected fish or infected water What can be done once VHS is in a lake? Nothing! No way to eradicate virus.
VHS Virus DNR Response 1. Restricted movement of baitfish and roe via FO-245. 2. Collected fish from numerous waters for VHSv testing 3. Disinfected salmonid eggs before entering hatcheries 4. Temporarily ceased stocking of northern pike and walleye 5. Limited walleye stocking for a few years - reduce risk of bringing VHSv into a hatchery or rearing pond - walleye only stocked below lowermost dams i.e., sites with Great Lakes access
6. Finally back to full walleye program in 2011 - walleye not very susceptible to VHSv Invasive Species What can I do to help? 1. Do not release live baitfish into any body of water. 2. Dispose of unwanted baitfish and fish parts in trash. 3. Do not move water between water bodies. drain boat, live well, trailer, etc. 4. Clean boats, trailers, and equipment. Disinfect live wells and bilges. 5. All everything to dry thoroughly.
D. Kenyon Minnesota DNR Thank You Great Lakes, Great Times, Great Outdoors www.michigan.gov/dnr
