Egans Errors 1?

Mr. Dan Egan has written a series of articles for the Milwaukee Journal Sentinel about invasives in the Great Lakes. The problem some of us have is with his cause and effects. We believe that many solutions to problems can be implemented now, at less cost, then a one size fits all, invasive fix. Please read the following and if you agree, contact your representatives and encourage them to try the quick and least expensive way to fix many of the problems on Lake Michigan.

Their theory; “In just a decade the filter-feeding mollusks have literally turned life upside down in Lake Michigan by sucking to the bottom so much of the plankton that sustained a healthy commercial fishery.” Source Milwaukee Journal Sentinel A graph is provided to show declining commercial harvests of four fish species in Wisconsin waters of Lake Michigan, with 1994 highlighted for mussels.

We then looked for confirmation of our theory of mismanagement before invasives and found support from the Great Lakes Science Center, “In a recently published paper, however, we argued that the decline in prey fish biomass is better explained by factors other than food-web-induced effects by dreissenids, including poor fish recruitment (that preceded the mussel expansion), shifts in fish habitat, and increased fish predation by Chinook salmon (Bunnell et al. 2009b).

As the saying goes, follow the money, we shall begin with the most valuable of commercial fish species, the yellow perch. The first problem we have is the Journal's combining of perch harvests from both Green Bay and Lake Michigan. Green Bay is more like Lake Erie then Lake Michigan. So let’s separate them, also someone neglected to include the verified and estimated illegal perch harvests from 1989-1992, so we did. Click on any chart to view the enlarged chart.
Chart 4
                  Chart 1                                      Chart 2                                      Chart 3                                     Chart 4
Chart 1: The only invasive are alewives appearing in 1949, perch harvests increase, crash, recover after stocking to crash again before the alleged critical year of 1994.
Chart 2: How we came up with the harvest numbers on chart 1: 1986 to 2003, by including CanAm and estimated illegal commercial perch harvests.
Chart 3: Confirming unhealthy harvest pressure is seen in the crash of young perch not entering the fishery. By 1993, one year before the alleged critical mussel year of 1994, only 2.3% as many 2 year old perch were produced in Lake Michigan as were produced in 1990. Commercial harvesting of perch start when they are 8 inches long, about 2 years old.
Chart 4: Lake Michigan Yellow Perch Graded Mesh Survey, source WDNR, finds by 1993 only 14% are female. Females grow faster then males, thereby are harvested sooner. Zebra mussels don't determine female survivability, as proof, when nets were removed, more females survived.

Our conclusion: With the perch population down by 72%, the destruction of the Lake Michigan yellow perch fishery was due to commercial overfishing, taking place before invasive mussels appeared. Lack of Spawning Stock Biomass(SSB) prevents the current recovery of the perch population as it did from 1965 to 1983, or until after the stocked perch grew to breeding size. Further proof Wilberg & Bence 2005. Inexpensive alternative fix to invasive control, stock perch again, est. cost $1.1 million.
Possible reason stocking hasn't taken place, because to do so would permanently remove yellow perch as a commercial species for harvest. WDNR reason of cost fails when compared to benefit. If 10 days of Sturgeon season is worth $3.5 million per year, then why wouldn’t 90 days of restored sport perch fishing be worth the same? More then enough to cover several years worth of perch stocking.
Alternative, wait another 20 years for possible perch recruitment to increase naturally, while risking extinction of the few remaining perch by incidental commercial harvest, disease such has VHS, invasive, environmental change, pollution such as estrogen, or some other unknown.

I believe that what was also missed was the negative effects on fishery health after the 1989 WI commercial quotas were put into place. see 1989.