Michigan Fisheries:The Big Picture

Presented by: Brian GundermanDate: November 8, 2011

Fisheries ManagementFisheries Management• Stocking - restore populations (sturgeon) - create fishing opportunities

lack of spawning habitat - adjust predator:prey ratios

• Regulations - prevent overexploitation - prevent spread of undesirable species - enforce principles of fair chase - reduce hooking mortality

D. Kenyon

Fisheries ManagementFisheries Management• Habitat Improvement - habitat altered due to dams, dredging, historic logging activity, erosion, shoreline armoring, etc.

Fisheries ManagementFisheries 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 FisheryLake Michigan FisheryForage Base 2010Acoustic (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 1992-2004Bottom trawl survey (Bunnell et al. 2011)• Bad news: total biomass low and similar to 2009

most abundant species = round goby

Yale.edu

Lake Michigan FisheryLake Michigan Fishery

Round goby

Bloater

Alewife

Ninespine stickleback

Rainbow smelt

Slimy sculpin

Deepwater sculpin

BOTTOM TRAWL

46% native

Alewife

Bloater

Rainbow smelt

ACOUSTIC

8% native

Lake Michigan FisheryLake Michigan FisheryChinook Salmon (Claramunt et al. 2010)• Stocking levels reduced since 1998• Variable survival, fishing effort, & natural reproduction• Natural reproduction average = 44%

Lake Michigan FisheryLake Michigan FisheryLittle Manistee Weir Returns

0

10,000

20,000

30,000

40,000

1968 1978 1988 1998 2008Year

# C

hino

ok s

alm

on

Invasive SpeciesInvasive Species

Asian Carp – BackgroundAsian Carp – BackgroundBighead

Silver

• Introduced to U.S. in 1970s

• Eat plankton

• Tolerant of cold water

• Often found in large, turbid rivers

• Potential vectors Chicago waterway Intentional release

Asian Carp - ResponseAsian 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 MusselsQuagga 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 MusselsQuagga 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 MusselsQuagga MusselsHow do quagga mussels affect aquatic ecosystems? 1. Eat algae

less food for zooplanktonless zooplankton for planktivorous fishes

2. Increase water clarityincreased plant growth

3. Excrete pseudofecesdecrease oxygen and pHincrease pollutant concentrations

4. Colonize pipes, boats, docks, etc.expensive and time consuming

Idaho Dept. of Agriculture

Starry StonewortStarry Stonewort

NY Sea Grant

michiganlakeinfo.com

• Algae – similar to Chara• Native to Europe• Found in Lake St. Clair in 1974• Spread to many inland lakes in last 15 years

boats, trailers, waterfowl• Proliferates rapidly• Forms dense mats in water depths up to 27 ft

Pullman & Crawford 2010

Pullman & Crawford 2010

Starry StonewortStarry Stonewort

Starry StonewortStarry StonewortEffects on Aquatic Ecosystems1. Reduces diversity of rooted aquatic plants2. Competes with planktonic algae for nutrients

increased water clarity3. Destroys spawning habitat for bass and bluegills4. Oxygen depletion fish kills5. Interferes with navigation

michiganlakeinfo.com

Starry StonewortStarry StonewortControl Options• Mechanical harvesting

• Algaecides“haircuts”

• Other herbicides?timing important

• Drawdowns?www.aquamog.com

www.prolakemgt.com

VHS VirusVHS 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

Wisconsin DNRD. Kenyon

VHS VirusVHS VirusWhat are the symptoms of VHS?

widespread hemorrhagesdroopy 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 VirusVHS VirusDNR Response1. Restricted movement of baitfish and roe via FO-245.2. Collected fish from numerous waters for VHSv testing3. Disinfected salmonid eggs before entering hatcheries4. Temporarily ceased stocking of northern pike and walleye5. 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 access6. Finally back to full walleye program in 2011

- walleye not very susceptible to VHSv

Invasive SpeciesInvasive SpeciesWhat 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.

Minnesota DNRD. Kenyon

Thank You

www.michigan.gov/dnr

Great Lakes, Great Times, Great Outdoors