Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Effects of Hypoxia on Food Webs Doran M. Mason

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, NOAA Mission Relevance NOAA 5-Year Research Plan Ecosystem Goal Advance understanding of ecosystems to improve resource management Develop integrated ecosystem assessments and scenarios, and building capacity to support regional management

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, How does the spatial extent and seasonal timing of hypoxia affect: –Fish growth and production? –Food web interactions? –Habitat quality and suitability for important fishes? How does the combined effects of hypoxia and other stressors affect fish abundance and community composition? What are the most effective tools to forecast food web interactions, habitat suitability and fish production in relation to hypoxia? Guiding Scientific Questions

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Modifies food web interactions? Food availability Foraging efficiency Increases fisheries harvest? Disrupts diel vertical migration? Maintenance costs Key Scientific Questions

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Approach Comparative across ecosystems High-resolution mapping of the pelagic food web in relation to hypoxia Data analyses and model development to assess the effects of hypoxia on food webs and production Ultimately will provide tools to forecast food-web interactions, habitat suitability and fish production in relation to hypoxia

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 6 Comparative Approach June-Oct 2005 Aug-Sept 2007 Lake Erie Gulf of Mexico Chesapeake Bay Spring, Summer, Fall

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 7 Consistent Sampling Trawling (fish species composition, samples for diet work) Zooplankton net and pump sampling (zooplankton) Zooplankton Temperature DO Light levels Chlorophyll a Fish Biomass

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 8 Hypothesis: Modifies food availability for fish Refuge from predators Implications Reduced access to food resources Reduced growth and production Gulf of Mexico: Moderate Hypoxia Latitude (degree) Depth (m) DO (mg/L) Zooplankton (mg/L) Relative fish biomass (dB) Dead Zone Zooplankton Fish

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 9 Hypothesis: Modifies food availability for fish Refuge from predators during mild conditions Lake Erie: Moderate Hypoxia Depth (m) DO (mg/l) Latitude (degrees) ZP (mg/l) Fish (dB)

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 10 Hypothesis: Modifies food availability High spatial overlap during extreme conditions Lake Erie: Severe Hypoxia

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 11 Prey Increased vulnerability Increased mortality Predator Short-term increase in consumption & growth Long-term? Hypoxia Effects on Foraging Efficiency Chesapeake Bay Hypoxic 28 o C Low DO – Cold Temperatures Lake Erie 27 o C Hypoxia Bay anchovy Walleye Striped Bass Smelt

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Hypothesis: Hypoxia Increases Fishery Harvest? Implications Concentrates commercial species on the edge, increasing vulnerability to fishery (e.g. yellow perch) # Hypoxic Days Areal Ratio Volume Ratio Commercial Catch Ratio Normoxic: Hypoxic Depth (m) DO (mg/l) Fish (dB) Lake Erie Dip in Oxygen Level Fish concentrate Dead Zone

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Disrupts diel vertical migration: maintenance costs Implications Increased maintenance costs Decreased growth and production Increased mortality Directly: thermal stress Indirectly: increased predation Impact of Hypoxia on Food Webs

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 14 Impact of Hypoxia on Food Webs Approximate depth of DIDSON Water column bottom at site of CTD cast Role of Behavior? Implications: Prey vulnerability Predator growth & production Imaging Sonar (Didson) CTD Profile

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 15 Partners Gulf of Mexico Florida Int’l University Louisiana Dept. of Fisheries and Wildlife Louisiana State University NMFS SE Regional Office Oregon State University Chesapeake Bay University of Maryland Lake Erie Ohio State University Purdue University University of Akron

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Products Large database across three ecosystems Diet Spatial Distribution and abundance across trophic levels Environmental variables (salinity, DO, temperature) GLERL Co-Guest Editor in a Special Supplement of the Journal of Experimental Marine Biology and Ecology on “Ecological Impacts of Hypoxia on Living Resources” GLERL contributed 8 of 20 manuscripts

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Future Direction

Great Lakes Environmental Research Laboratory Review – Ann Arbor, MI November 15-19, Click to edit Master text styles –Second level Third level –Fourth level »Fifth level 18 Thank you! Questions?