2026-05-22 イリノイ大学アーバナ・シャンペーン校
＜関連情報＞
- https://aces.illinois.edu/news/walleye-return-same-spawning-hotspots-highlighting-need-habitat-protection
- https://www.frontiersin.org/journals/fish-science/articles/10.3389/frish.2026.1758559/full
オガア（ウォールアイ、Sander Vitreus）の産卵場所と定着性の特定：漁業管理への示唆 Identifying spawning sites and fidelity of Ogaa (Walleye, Sander Vitreus): implications for fishery stewardship
Kayla Lenz,Aaron Shultz,Carl Klimah,Adam Ray
Frontiers in Fish Science Published:21 May 2026
DOI:https://doi.org/10.3389/frish.2026.1758559
Abstract
Many giigoonyag (fishes) species worldwide display spawning site fidelity, making them especially susceptible to habitat disturbances in spawning areas. Identifying spawning sites and the degree of fidelity to these sites may be key to maintaining the relationship between humans and giigoonyag for future generations. Here, we use Indigenous knowledge to define Ogaa (Walleye Sander vitreus; singular) spawning periods, identify spawning sites, characterize habitat use, and quantify spawning site fidelity of 70 adult Ogaawag (Walleye; plural) during the 2019–2021 spawning seasons, in Mille Lacs Lake, Minnesota using an acoustic telemetry array. Ogaawag movements were tracked during the spring spawning period, and fish depth, number, and frequency of fish detected by each receiver were used to identify spawning sites and determine the relative importance of each spawning reef. Habitat characteristics such as substrate type, wind/wave action, and shoreline development were compared across reefs. We found that approximately 64% of Mille Lacs Ogaawag returned to the same site to spawn in 2020 as in 2019, 32% returned to the same site but also used other spawning areas, and only 4% used completely different spawning grounds across years. We identified areas with rocky and/or hard substrate, exposed to wind/wave action, and near undeveloped shorelines to be hotspots of Ogaawag activity during spawning. We also observed a rare example of skipped spawning by a female Ogaa. This study offers new insight into the rates of spawning site fidelity and the form that that fidelity takes in inland, fully-mixed waters, as well as provides evidence that Ogaa spawning hotspots may be correlated to areas of low or no onshore development. These findings may alter how humans act as stewards of this species, such as conserving spawning sites and adjacent habitats to improve recruitment and be a template for how Indigenous and Western societies can move toward a more inclusive life-history and ecosystem-based approach to sustaining their relationship with giigoonyag.
