Wolf River Sturgeon Spawning Report - Friday April 13, 2012
Sturgeon Spawning Occurring at Keshena Falls on Wolf River in the Menominee Indian Reservation for the 1st time in over 100 Years
Attached is a news release from the Menominee Indian Tribe of Wisconsin announcing the documentation of lake sturgeon spawning below Keshena Falls on the Wolf River in the Menominee Reservation. This is the first documented return of spawning lake sturgeon to this site held sacred by the Menominee people in over 100 years; a result of joint efforts between the Tribe and the State of Wisconsin, WI DNR, to restore resident and spawning lake sturgeon to this section of the Wolf River and the Menominee Reservation. Two dams downstream of the reservation have prevented the sturgeon from migrating up to the historic spawning areas on the Reservation below Keshena Falls for the last Century. The State has been working with the Tribe for the last 20 years to restore lake sturgeon to Reservation waters, and, under the leadership of DNR Secretary Cathy Stepp, entered into a new 10 year agreement in 2011 which included capturing 100 sturgeon per year from the Wolf River below the dams and transferring them upstream for release in the Wolf below Keshena Falls to create a spawning stock of fish on the Reservation. The strategy appears to be working well as spawning fish were observed below the Falls by Tribal members on Wednesday April 18 which will be recorded as an important historical day for all associated with the project. Seventy-six of the 100 fish transferred and released below Keshena Falls were surgically fitted with internal sonic telemetry transmitters that will last ten years and allow Tribal and DNR fisheries staff to track the movement and migration patterns of the fish. Questions about the project can be directed to Menominee Tribal Chairman Craig Corn at cacorn@mitw.org or at 715-799-5114.
Status of 2012 Lake Sturgeon Spawning Run on Wolf River Shawano and Downstream
The lake sturgeon spawning activity on most of the river from Shawano downstream has wound down, with a few fish actively spawning yet yesterday below Shawano dam, and a few other sites all the way down to Leeman. The sunny days followed by freezing nights have resulted in wild swings in daily water temperatures but the overall trend is upward since temps bottomed out on Wednesday 4/11. If this trend continues I expect "second" runs to occur at spawning sites from New London upstream to Shawano possibly by this weekend or early next week. The very warm weather (70's daytime, 50s night) the next two days could bring the second run on. We saw fish porpoising again at Bamboo Bend in Shiocton yesterday and heard reports of fish seen at other sites as well. Usually the 2nd and sometimes 3rd runs consist of much lower numbers of fish and are driven by a handful of females that ovulate at a higher temperature or at a greater amount of thermal units.
Typically in spring, we will have stretches of very warm weather which cause water temps to rise, followed by days of very cold weather, often with snow or cold rain, which cause the water temps to drop again. Fully developed female lake sturgeon, ready for spawning, appear to respond to this temperature roller-coaster individually with some fish spawning after the first increase into the species' optimal spawning temperature range (50 to 60 F), some (often most) spawning at a little higher temp, and finally the last group spawning at the highest temps or after temperatures increase again into optimum range following a cold spell during the main spawning event. I have observed lake sturgeon spawning at water temperatures ranging from 36 F to 70 F.
Sturgeon have been around for over 150 million years and part of their success may be rooted in the 2nd and 3rd run phenomenon; and this year is a good example of the importance of 2nd and 3rd runs. The first major spawning activity this year was the earliest we have on record back to the early 1950s due to the exceptionally warm weather in mid March. The sturgeon that spawned in this early run between March 21 - 29 laid their eggs while flows and water levels were still reasonably high on the Wolf River. Once the eggs are laid they need about 10 days to hatch and then another 10 days for the fry to stay on the spawning site in the interstitial spaces of the rocks using up their yolk sac before they migrate downstream to their summer feeding areas. The timing of all of this require sustained water levels on the river for at least 20 days post-spawn (spring water flows and levels on the Wolf are driven exclusively by spring snowmelt and timely rains). This year flows and water levels on the Wolf River dropped over 3 feet during the 20 days following the "1st run" of sturgeon spawning, leaving most of the laid eggs high and dry with likely very low survival and low fry production. The "2nd run" occurred after the Wolf had completed most of its drop in water flows and levels; and if we get a "3rd run", water flows and levels will likely be even more stabile for the 20 days following egg deposition. For these reasons, we typically see lake sturgeon spawning activity lasting often over a month on the Wolf River proceeding in fits and starts as spring rolls on.
You can still see sturgeon on the Shawano "Sturgeon Cam" at http://www.wolfrivercam.com/Shawano%20Dam.html but these appear at the moment to be males waiting around for the "2nd run" to occur at the Shawano spawning site, which could happen over the next few days. As long as there are some females still holding adjacent to a spawning site that have not ovulated yet, the males, despite spawning perhaps already for days or weeks, will wait for weeks for these last females to come in and lay their eggs before they pack it in for the year and return downstream to the lakes. Females, after they finish spawning, waste little time before they begin drifting downstream back to their home range where they will live for several years recovering and getting ready for their next spawning run 3-5 years later.
If the fish start up again, I'll let you know. Otherwise this will likely be my last "daily" report of the 2012 sturgeon spawning season. Once we get all of the data entered and proofed and complete our initial analysis, I (or perhaps our new Sturgeon Biologist Ryan Koenigs) will send out the final summery of this spring's sturgeon spawning assessment.
Till then,
Ron
Ronald M. Bruch, PhD
Upper Fox-Wolf Fisheries Work Unit Supervisor
Wisconsin Department of Natural Resources
625 E County Rd Y, Suite 700
Oshkosh, WI 54901
USA
phone: (920) 424-3059
fax: (920) 424-4404
e-mail: ronald.bruch@wisconsin.gov
Sturgeon Hot-Line: (920) 303-5444