Lake Sturgeon Rehabilitation Using Streamside Rearing Facilities
Grant: # 0671
Grant Amount: $583,212.00
Board Decision Year: 2005
U.S. Fish and Wildlife Service - Green Bay Fishery Resources Office (New Franken)
Green Bay Fishery Resources Office
Elliott, Rob (firstname.lastname@example.org) 920-866-1762
GLFT - Ecosystem Health and Sustainable Fish Populations-E - Ecological and biological fisheries research to inform management
Lake sturgeon rehabilitation is currently a focus of many Great Lakes agencies. Strategies to increase their numbers have been identified and implemented because lake sturgeon populations are extremely small and believed to be a fraction of their historical abundance. Stocking has traditionally been conducted in a manner where gametes are collected, hatched and reared at a hatchery off-site from where the fish will be stocked. However, concerns have been raised with this practice because of the risks posed by stocked fish straying into rivers other than where they were stocked and spawning at disproportionately high rates with non-stocked remnant populations (Holtgren et al. 2007, Welsh et al. 2010). Within the Lake Michigan Basin genetically distinct remnant populations have been identified and the protection of these populations is a priority (DeHaan et al. 2006). The Lake Sturgeon Task Group has identified streamside rearing facilities as a method that may maximize the likelihood of imprinting and thus minimize the risk of stocked fish straying.
In 2005, four management agencies in the Lake Michigan Basin (Wisconsin Department of Natural Resources, Michigan Department of Natural Resources, US Fish and Wildlife Service and Little River Band of Ottawa Indians (LRBOI)) began meeting to determine if streamside rearing facilities (SRF), patterned after the initial successful Manistee River trailer operated by LRBOI, could be deployed in Wisconsin and Michigan to begin the rehabilitation of lake sturgeon in important historical streams. This group decided to pursue internal and external funding to accomplish this task with five specific goals for the project including:
- Design and build streamside rearing facilities on the Milwaukee and Manitowoc Rivers (later moved to Kewaunee River), Wisconsin and Cedar and Whitefish Rivers, Michigan.
- Use streamside rearing facilities to annually rear and stock lake sturgeon in each river.
- Compare growth and condition factors of SRF lake sturgeon to traditional-hatchery reared and wild lake sturgeon.
- Assess short -term movement patterns and river retention of stocked lake sturgeon.
- Collect, analyze and archive tissue samples from adult broodstock and representative progeny to determine a) genetic diversity of stocked fish, b) genetic diversity of returning adults in future years, and c) straying rates in future years.
Four new SRFs were constructed during the fall and winter of 2005 and delivered in April 2006. They were deployed on the Whitefish River and Cedar River in Michigan and the Milwaukee River in Wisconsin. The fourth trailer was to be deployed on the Manitowoc River, WI but WDNR did not have the site prepared for the trailer and could not raise fish at this site in 2006. The Manitowoc River trailer was utilized on the Manitowoc in 2007 but sat idle in 2008 and was moved for the 2009 rearing season to the Kewaunee River as a more suitable and more permanent location.
These trailers have been used since 2006 to produce large fingerling lake sturgeon for rehabilitation in selected Lake Michigan streams. From 2006-2011, over 13,500 lake sturgeon were raised and stocked using SRF’s.
Growth and condition varied by facility and year, but in all cases were comparable to what was observed in traditional hatcheries. Variation across SRF’s was likely influenced by the combination of water temperature /quality, length of growing season, density of fish in rearing facility tanks, and feeding regimes. In most years, Manistee, Milwaukee, and Kewaunee SRF reared fish maintained a larger size during the growing season and reached a larger mean size at release than Whitefish River and Cedar River SRF fish. Growth and condition of SRF reared fish was also similar to that observed in wild Lake Michigan populations.
Two movement studies were conducted as part of this grant. Wisconsin investigated the movement patterns of recently stocked lake sturgeon fingerlings in the Milwaukee and Kewaunee Rivers from egg donor populations while LRBOI investigated the movement patterns of wild and SRF -reared lake sturgeon in the Big Manistee River. In Wisconsin’s study, the hydrophone receivers recorded movement at night, indicating that fingerling lake sturgeon must move almost exclusively during night time hours. Secondly, the Wisconsin study showed that these fish, in general, moved rapidly down the river and into the harbor or lower estuary of each river after about 30 days. This pattern of downstream dispersal of age 0 lake sturgeon, predominantly at night, during summer to early fall has also been documented in wild populations (Holtgren and Auer 2001, Auer and Baker 2002, Benson et al 2005, Caroffino et al. 2009). Because these fish appear to be acting similar to wild fish and they were raised and imprinted on local river water there are minimal concerns about these SRF reared fish straying from home streams to spawn with established populations when they become sexually mature.
The LRBOI study shows that the movement patterns and habitat selected between SRF -reared and wild lake sturgeon were very similar. The average weekly distances traveled by SRF fish ranged from 0.05–2.28 km (of 46 km surveyed) while wild fish traveled 0.04–2.81 km (Mann et al. 2011). Both SRF and wild fish used common benthic habitats. Indications from this research suggest that by September of each year the SRF -reared age-0 lake sturgeon attained a size similar to that of their wild cohorts and exhibited similar movement patterns and substrate association.
2005.0671 Project Synopsys
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