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Update from Ron Bruch on Feb. 21, 2011

February 21, 2011

Wisconsin and Lake Winnebago are once again covered in 12+ inches of white.  Just yesterday we could see the grass and a few days before that it felt like spring.  Well, I can tell you that it most definitely doesn’t feel like spring anymore.  I’m actually impressed by the sturgeon report today–with the storm and deep snow I didn’t think anyone would be out there.  Sure enough, one sturgeon was registered.  Congrats Brad Buksyk for the largest (and only) sturgeon of the day! 

This updated was posted with permission from the WDNR and Ron Bruch:

“Winnebago Sturgeon Spearing Report – Monday February 21

See Sturgeon Vignette below: “This sexing and staging stuff – what’s do these numbers, like F1, F6, and M2, mean?”

Upriver Lakes season is now closed for 2011.

Nearly another record today for Lake Winnebago Sturgeon Spearers: Only one (1) fish registered for both Lake Winnebago and the Upriver Lakes today. This ties the records for only 1 fish registered during a day set during the 1969 and 1973 spearing seasons, but was one fish too many for breaking the all-time lowest daily tally of registered sturgeon set on several days during the 1969 and 1973 seasons. On the opening weekend of the 1973 season no fish were registered on either Saturday or Sunday. Both the 1969 and 1973 seasons ended up with a registered harvest of 8 fish.

In both 1969 and 1973 poor travel conditions on the lake, similar to this year, in addition to terrible water clarity resulted in the low harvests in those years. Also, the Winnebago sturgeon population was at a critical low point at this time, which contributed to the lower harvests overall as well. The cloudy water, common throughout the 1960s, 1970s and 1980s, was dreaded and despised by the spearers, but was actually one of the major factors that contributed to the recovery of the Winnebago lake sturgeon stock from the 1960s to the 1990s by keeping spear harvest rates low for more than 30 years. Several decades of overharvest, both illegal and legal, during the 1930s through the 1950s resulted in a severely diminished lake sturgeon stock in the Winnebago System by the late 1960s. A number of spearers (Bill Casper, Dan Groeschel, Bob Blanck, Vic Schneider, and Lloyd Lemke) concerned at the time about the low harvests in the 1960s and 1970s joined forces to form the first chapter of Sturgeon for Tomorrow in 1977 to help save and improve the Winnebago sturgeon population. Since 1977 four other chapters have formed around the Winnebago System and the group has raised and funded over $750,000 of projects in sturgeon management and research, including the annual Sturgeon Guard Program, and the upper Fox Sturgeon Restoration Project.

Back to the 2011 season……….Due to reduced effort we will keep the following registration stations closed until further notice: Calumet Harbor, Quinney, and Harrison Town Hall. Spearers on the east shore of Lake Winnebago are asked to take their fish to Stockbridge to register them. We will watch to see if spearing pressure increases going into next weekend, and if needed, we will re-open some stations at that time.

Largest and only fish of the day was 62.3 lb, 63.0″ M1 registered at Waverly Beach Station by Brad Buksyk of Neenah.

Totals by lake area and harvest category:

Lake Winnebago: 0 Juvenile Females
0 Adult Females
1 Male
1 Lake Winnebago Total for the Day – 989 total for season

Upriver Lakes: 0 Juvenile Females
0 Adult Females
0 Males
0 Upriver Lakes Total for the Day – 333 total for season

System-Wide: 0 Juvenile Females
0 Adult Females
1 Male
1 System-wide Total for the Day

1322 System-wide Total for the Season

“This sexing and staging stuff – what’s do these numbers, like F1, F6, and M2, mean?”

Although we have had mandatory registration of sturgeon harvested during the Winnebago spearing season since 1955, we did not start regularly checking the sex and maturity of the harvested fish until 1991. We expanded the harvest assessment in 1991 to include sex and maturity data because at the time we saw the percentage of large fish over 100 lbs in the harvest drop to historic lows (less than a half of 1%), and knowing the females are typically larger than the males, we suspected that adult females might have been making up a disproportionate amount of the harvest.

The problem at the time though, was that there was no handy manual readily available on how to sex and stage lake sturgeon – so – we ventured into this task knowing we would have to develop our own. Starting in 1991 we examined as many gonads of harvested lake sturgeon during the spearing season as possible; literally dissecting, weighing, examining, sampling, and photographing 100’s and 100’s of sturgeon gonads from both males and females. (I probably have the largest collection of sturgeon gonad photos on the planet – I’m going to have to think hard to whom I will eventually will this collection to.) After collecting, photographing, and studying these lake sturgeon gonads for several years, and after working with a couple of researchers at the University of Manitoba to do histological analyses of the various gonad stages we identified, we were able to put the whole story together in a way that made the most sense to our sturgeon management program.

What we found is that sturgeon, both males and females go through various identifiable stages of gonadal development as part of a continuum of development that is part of their normal reproductive cycle. Keep in mind that our lake sturgeon don’t spawn for the first time until they are relatively old (males age 14-31, females age 20-34), and that prior to their first spawn, both sexes appear to go through an extended period of development (puberty). The stages we settled on that were distinct and readily identifiable were: Fv – juvenile female, F1 – female in first or subsequent maturation cycles but with undeveloped eggs (tiny-white egg fish), F2 – female in early stages of yolk development (early yellow egg fish), F3 – female in later stages of yolk development but prior to egg pigmentation (late yellow egg fish – summer stage), F4 – gravid female with fully developed and pigmented eggs (black egg fish), F5 – ovulating female (spawning fish), F6 – spent female, Mv – juvenile male, M1 – male in first or subsequent maturation cycles but with undeveloped testis, M2 – male with fully developed testes (pre-spawning and spawning), M3 – spent male (late spring – summer stage). Through the financial support of Sturgeon for Tomorrow, we published these findings as the Lake Sturgeon Sexing and Staging Guide in 2001. I also developed a handy two-page “pocket” guide for sturgeon sexing and staging that can be used by spearers to better understand what it means when we shout out “M2, M1, F2, F6, etc” at the spearing registration stations each winter. I’ve attached a copy of the pocket-guide to this report.
The numbers, “1, 2, 4, 6, etc” do not necessarily mean that the fish is in its first, second or fourth year of development between spawns – they simply refer to the stage the fish is in at the time of harvest. For example, an adult female will be an F5 when she is spawning, an F6 immediately after she finishes spawning and for about the next year before she becomes an F1. She will stay in this F1 stage re-building her gonadal fat reserve for about another year before she quickly goes through stages F2, F3, and F4 in the last 16 months or so before she spawns again as an F5 – 4 years after she last spawned as an F5.

So – the next time you hear us shout out your or your spearing buddy’s fish’s sex and stage, you can turn to the crowd around you and confidently say “Yea – that F2’s a yellow egg fish – 14 months from when she would have spawned next – hang around these registration stations enough and you begin to pick up the lingo”.

Till tomorrow,

Ronald M. Bruch, PhD
Upper Fox-Wolf Fisheries Work Unit Supervisor, Wisconsin Department of Natural Resources”

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