Research about Canada, United Sates

USGS2026

Spatial units to support Lake Erie Cisco Coregonus artedi restoration

At the request of the Lake Erie Committee, spatial units for Lake Erie Cisco were delineated during spring 2024. Spatial units correspond to the reproductive habitat of extirpated (unoccupied spatial units) and extant (occupied spatial units) populations. Spatial units were delineated using a Council of Lake Committees-endorsed method that involves synthesizing data for evaluation by a panel with expertise on the focal organisms and ecosystems. By examining catch, survey, observational, and genetic data, an expert panel determined that no viable Cisco populations remain in Lake Erie. Experts delineated one eastern and one western unoccupied Cisco spatial unit in Lake Erie based on interpretation of historical movement and spawning locations and timing. The expert panel also identified eleven key questions that can be investigated to further inform Lake Erie Cisco restoration. The two unoccupied spatial units will form the basis of a follow-on threats assessment and population viability models that together provide fishery managers science-based planning tools for Lake Erie Cisco restoration.

Lake Erie↗

USGS2024

Risk of capture is modified by hypoxia and interjurisdictional migration of Lake Whitefish (Coregonus clupeaformis)

Interjurisdictional migrations lead to seasonally changing patterns of exploitation risk, emphasizing the importance of spatially explicit approaches to fishery management. Understanding how risk changes along a migration route supports time-area based fishery management, but quantifying risk can be complicated when multiple fishing methods are geographically segregated and when bycatch species are considered. Further, habitat selection in dynamic environments can influence migration behavior, interacting with other management objectives such as water quality and habitat restoration. As a case study, we examined a novel acoustic telemetry data set for Lake Whitefish in Lake Erie, where they migrate through multiple spatial management units that are variably affected by seasonal hypoxia and host a variety of fisheries. Combining telemetry results with fishery catch and water quality monitoring, we demonstrate three exploitation risk scenarios: i) high risk due to high residency and high catch, ii) high risk due to high residency in time-areas with moderate catch, and iii) low risk due to residency in time-areas with low catch. Interestingly, occupation of low risk refugia was increased by the development of hypoxia in adjacent areas. Consequently, fishery management goals to sustainably manage other target species may be directly and indirectly linked to water quality management goals through Lake Whitefish.

Lake Erie↗