A Unified Model of Walleye Recruitment
Understanding the drivers of recruitment enables effective fisheries management and allows us to predict how fish will respond to environmental change
How environmental factors, stock size, and other biological drivers regulate fish recruitment and how their influence varies spatiotemporally is a key knowledge gap in most ecosystems. We will synthesize existing knowledge both conceptually and quantitatively to identify drivers of walleye recruitment and how they vary or are similar across systems.
Phase 1: Conceptual model of walleye recruitment
With the support of the Great Lakes Fishery Commission, we will synthesize knowledge of the drivers of walleye recruitment across North American walleye populations. We will explore how and why the drivers of walleye recruitment vary spatiotemporally within and among walleye stocks. This assessment will be completed during summer of 2021, and will bring together a diverse group of professionals with relevant expertise in fisheries. Participants will discuss the state of the science and contribute ideas to develop a conceptual model of the key drivers of walleye recruitment. Together, we will develop and publish a conceptual model for the key drivers of walleye recruitment, at least one manuscript to be submitted to a peer-reviewed journal, and identify relevant datasets to be compiled for a subsequent quantitative synthesis.
Objectives:
1. Provide relevant background information on walleye research/knowledge and describe the state of the science on drivers of walleye recruitment from across North America
2. Identify common themes and/or variation in recruitment research and discuss how they are related
3. Develop a conceptual framework describing the environmental, biotic, and physicochemical factors independently and interactively regulating walleye recruitment
4. Collate datasets to prepare for a quantitative assessment of the conceptual framework (Phase 2)
Summer 2021
Phase 2: A quantitative assessment of drivers of walleye recruitment across North America
Using the data compiled as part of Phase 1, we will quantify variability in walleye productivity across Great Lakes and inland lake walleye populations for which stock and recruitment time-series data exist. Such data are available for many Great Lakes walleye stocks (e.g., Lake Erie, Saginaw Bay, Bay of Quinte, Green Bay, Black Bay), as well as for inland lake populations in Ontario, Minnesota, New York, and Wisconsin. We will then use stock-recruitment models to evaluate temporal and spatial patterns in walleye productivity. Finally, we will examine relationships between walleye recruitment and potential environmental drivers across populations through time. Our model will evaluate interactions among physical drivers and will incorporate predictive abilities such that our final unified model of walleye recruitment can be used to inform management approaches into the future.
Objectives:
1. Synthesize data and knowledge across wide environmental gradients to identify patterns and variability in the drivers of walleye recruitment
2. Quantify temporal and spatial variability in productivity of walleye stocks throughout North America
3. Develop a unified model to understand and predict walleye recruitment from environmental and biotic variables in the Great Lakes and beyond
Questions
1. Do the physical drivers of walleye recruitment vary among lakes?
2. Do certain ecosystem or population characteristics buffer walleye populations from the influence of physical conditions?
3. Are walleye recruitment dynamics and productivity varying because of climate change or species invasions throughout the Great Lakes region?
2021 - 2022