Why was this project funded? -Novel approach -Not business as usual -Uncomfortable -Confusing -May not be possible in 5 years -Potentially very exciting $$ $$$$ $ $ $ $

End-point #2: Fish production Adaptive Integrated Framework (AIF): a new methodology for managing impacts of multiple stressors in coastal ecosystems TEAM: Tomas Hook, Tammy Newcomb, Craig Stow, Scott Peacor, Steve Pothoven, Steve Brandt, Hank Vanderploeg, and Tom Nalepa

Overview 1)Background 2)Potential effects of stressors on fish production 3)Potential research approaches a)Modeling b)Ecosystem survey and empirical research 4)Issues to consider

Yellow perch Walleye Percids in Saginaw Bay Historically second largest commercial fishery in Great Lakes. Walleye collapse ~1950 due to eutrophication, over-fishing, invasive species, etc. Recent collapse of L. Huron alewives has led to improved reproductive success, but very poor growth and long-term survival. Fielder and Thomas 2006 MI-DNR; Fielder et al JGLR

Percid Production Requires a Balance Within the Ecosystem Yellow perch Zooplankton Benthic invertebrates Invasive Species Moderate temperatures Mesotrophic conditions Balance between sufficient pelagic and benthic prey

Overview 1)Background 2)Potential effects of stressors on fish production 3)Potential research approaches a)Modeling b)Ecosystem survey and empirical research 4)Issues to consider

Ludsin et al, unpub. data Loading effects on percid production Recruitment linked to river discharge. Mechanisms unclear. Too much loading probably bad.

Ecosystem engineering and the disrupted food web of Saginaw Bay. The substrate provided by the shells provides substrate for benthic plant and invertebrates, and increased light increases benthic plant production as well as potentially increasing predation intensity of visual (invertebrate and vertebrate) predators. The red shaded species are non-indigenous species. Invasive species effects on percid production

Black dot: Ponar samples for total benthos (1987 and 1988) Circled black dot: Ponar samples for total benthos ( ) X: diver samples for zebra mussels ( ) Location of sites sampled for benthos in

Density Biomass Mean density and biomass of zebra mussels at sites with hard substrate in inner Saginaw Bay in

Mean biomass of non-dreissenids at deep, silty sites in inner Saginaw Bay ( ) Total Chironomids

Non-dreissenid biomass; Shallow, sandy sites Total Gammarus

Climate change effects on percid production Temperature is the “master variable” for fish May also affect: –Watershed loading –Water levels –Community composition

Yellow perch bioenergetics 24 o C 11 o C 15 o C Respiratory cost(g g -1 d -1 ) Respiratory cost (g g -1 d -1 ) activity (x2) *Model run for a 20 g adult yellow perch (5942 J/g); Chironomid (3138 J/g); Zoop. (2510 J/g)

Yellow perch bioenergetics 24 o C 11 o C 15 o C Maintenance consumption (g/d) Maintenance consumption (g/d) activity (x2) *Model run for a 20 g adult yellow perch (5942 J/g); Chironomid (3138 J/g); Zoop. (2510 J/g)

Overview 1)Background 2)Potential effects of stressors on fish production 3)Potential research approaches a)Modeling b)Ecosystem survey and empirical research 4)Issues to consider

Fish Models

MI-DNR Saginaw Bay Surveys Spring sampling of river spawning walleye (1981- present) Fall bay-wide surveys of fish populations –Gillnet (1989-present) –Bottom trawls (1971- or 1986-present) –Abundance, size, condition, age, diets Smattering of additional data from 1926-present

Empirical models 1)Regression models -(e.g., Fielder et al JGLR) 2)Neural networks -(trained on meta-data and then applied) 3)Bayesian probability networks -(hocus-pocus vodoo)

Coupled 3-D process –based models Saginaw Bay Ecosystem Model (SAGEM) –Deterministic, process-based model –Phytoplankton model first developed in 1970’s –Updated to include: Multi-class phytoplankton Zebra mussel bioenergetics PCB fate, transport and lower food web bioaccumulation Benthic algae productivity –Latest version: Bierman et al JGLR 2005 Will be coupled to fish individual-based model

Next Individual Add new individuals Forage ƒ(fish size, temperature, prey densities, water clarity) Respire (bioenergetics) ƒ(fish size, temperature, food consumed) Predation Mortality ƒ(fish size, current location) Starvation Mortality ƒ(fish size, % storage tissue) Move? ƒ(fish size, current location) Next Day Loop through individuals

Swimming distance Reactive distance and encounter rate Optimal foraging Foraging: Stochastic capture success Consumption

Overview 1)Background 2)Potential effects of stressors on fish production 3)Potential research approaches a)Modeling b)Ecosystem survey and empirical research 4)Issues to consider

Fish-related ecosystem chracterization

Fish sampling Collect (monthly spring-fall) 1) Young percids 2) Potential interacting biota prey competitors predators

Fish sampling Quantify : fish size age diets growth (incl. short-term) mortality Relate to : available prey physical conditions predation pressure

Dreissenid Abundance and Biomass: Needed for estimates of nutrient excretion, filtering capacity, and materials cycling (carbon, energy). Key question: has the population remained stable since ? Macroinvertebrate Abundance and Biomass: Needed for estimates of food available to fish. Emphasis on the dominant taxa: (Chironomidae at deep sites and Gammarus sp. at shallow sites.) Proposed Effort for Benthic Community

New Links—emphasizing the microbial food web (conceptual) and invaders (real)

Zooplankton sampling Vertical tows of 64µm net Collect small zooplankters Oblique tows of 153µm net Collect large zooplankters

Experimental Research Examples: Effects of water clarity on fish foraging Effects of dreissenid shells on fish foraging efficiency Effects of dreissenids on P-availability

Overview 1)Background 2)Potential effects of stressors on fish production 3)Potential research approaches a)Modeling b)Ecosystem survey and empirical research 4)Issues to consider

Nearshore sampling Nearshore areas potentially important nursery grounds Nearshore sampling not described in proposal How will we consider these habitats?

Invasive species Proposal refers to invasive species, but really focuses on dreissenids Is the invasive species stressor really just a dreissenid stressor? Or, will we explicitly consider effects of other stressors? –Bythotrephes –Round gobies –Phragmites

Saginaw Bay Story (summary) Mussels knock down chlorophyll in Spring Chlorophyll & Microcystis increase during summer

Adaptive Integrative Framework (AIF)

Microzooplankton is more important than phytoplankton to zooplankton: Leptodiaptomus sicilis (calanoid) feeding on microzooplankton vs. phytoplankton in Lake Michigan Also remember: cyclopoids don’t eat phytoplankton!

Ecosystem engineering and the disrupted food web of Saginaw Bay. The substrate provided by the shells provides substrate for benthic plant and invertebrates, and increased light increases benthic plant production as well as potentially increasing predation intensity of visual (invertebrate and vertebrate) predators. The red shaded species are non-indigenous species. Question: Is Cercopagis or Bythotrephes important in the bay?

Saginaw Bay Story (summary) Mussels knock down chlorophyll in Spring Chlorophyll & Microcystis increase during summer

Microzooplankton is more important than phytoplankton to zooplankton: Leptodiaptomus sicilis (calanoid) feeding on microzooplankton vs. phytoplankton in Lake Michigan Also remember: cyclopoids don’t eat phytoplankton!

New Links—emphasizing the microbial food web (conceptual) and invaders (real)