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QUANTITATIVE TOOLS FOR ASSESSING AND MANAGING CISCO POPULATIONS

Cisco have played an important role in Great Lakes fisheries and ecosystems, particularly in Lake Superior. While some Lake Superior cisco stocks have recovered from declines in the last century, recent increases in fishing effort have raised concerns. Currently the quantitative tools available for informing cisco fishery management are limited. Given the importance of cisco, the development of informed harvest management strategies is critical to avoid stock collapses and subsequent ecological and fishery repercussions. We have proposed to use of existing data to assess selected cisco stocks in Western Lake Superior, evaluate what data are needed, including the frequency of their collection, to produce reliable estimates of cisco stock abundance, and evaluate alternative harvest policies. To achieve these objectives we will obtain and organize relevant data from a number of areas in Western Lake Superior. Hundreds of kilometers of hydroacoustic data have been collected in portions of Wisconsin, Minnesota, and Ontario waters for nearly a decade, as hydroacoustics is the preferred assessment gear of each agency. Biological information is also collected during hydroacoustic surveys, including lengths, weights, and otolith-based ages. Additional relevant information includes the USGS trawl survey indices for age-1 fish, and fishery harvest and associated biological information. We will use these data we will develop an appropriate age- or size-structured assessment model for several different stocks. The choice between age- and size-based assessments will be based on available data and initial assessment performance. We will then refit the stock assessment models using subsets of available data to determine how model performance depends on frequency and amounts of hydroacoustic and biological data. We will use assessment results and information from the literature we will develop stochastic simulation models and use these to evaluate different harvest policies (e.g., different exploitation rates). Each stage of this project will be carried out in close association with biologists from the Lake Superior Technical Committee.

Status
In progress
Type
Project
Start Date
End Date
Scope of Study
Literature / Existing Data
Theoretical
Scale of Phenomena
Population
Processes
Natural Ecological Processes
Resource Management
Fisheries
State Province
Minnesota
Ontario
Wisconsin

The Great Lakes - St. Lawrence Research Inventory is an
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up-to-date information about research projects in the
Great Lakes - St. Lawrence Region.