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Author Topic: Altered course in Lake Michigan stocking in 2017  (Read 6855 times)

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Steeliebob

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #15 on: July 27, 2016, 02:09:29 PM »

Part of the problem with salvaging the alewife population is that the DNR is planting millions of fish every year right in the heart of the alewife grounds. On top of that Wisconsin, Illinois, and Indiana are doing the same thing. Cutting back on Lake Trout planting by 550,000 is not going to do anything. Do the math all four states probably plant close to 10 million fish per year in Lake Michigan and/or rivers that flow into Lake Michigan. Most of these fish eat alewife. I would be considering some changes in planting locations which may or may not help the alewife.
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Shawnbo

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #16 on: July 27, 2016, 03:01:13 PM »

Part of the article Keith posted on cormorants and their diet.

Ludwig et al. (1989) collected 8,512 regurgitated food items from adults and young birds handled. Alewife and nine-spine sticklebacks each accounted for 41% by number (1 species of crayfish, all the rest were fish, in 18 taxa). By biomass, the most important species were alewife (57%), yellow perch (13%), rainbow smelt (8%), and white sucker (7%); weights of sticklebacks averaged 1.9 g, of alewives 19 g. Diet varied both seasonally and geographically; by Aug, diet at all 4 study areas was 100% alewife in all colonies sampled. Overall, forage fish accounted for 88% of food items (66% of biomass). Fish species of local commercial importance (such as panfish) constituted 12% by number (34% by weight), including yellow perch (3%, 13%), smelt (7, 8), and sucker (<1, 7). No lake trout or common whitefish, the two important commercial fish in Lake Superior, were found. Cormorant diet in Lake Superior in 1983 was examined by Craven and Lev (1987).
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Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #17 on: July 28, 2016, 07:01:58 AM »

Part of the problem with salvaging the alewife population is that the DNR is planting millions of fish every year right in the heart of the alewife grounds. On top of that Wisconsin, Illinois, and Indiana are doing the same thing. Cutting back on Lake Trout planting by 550,000 is not going to do anything. Do the math all four states probably plant close to 10 million fish per year in Lake Michigan and/or rivers that flow into Lake Michigan. Most of these fish eat alewife. I would be considering some changes in planting locations which may or may not help the alewife.

First thing to consider...the "Math". Depending on planting conditions, size of fish planted and species planted, survival to adulthood can be 2-5%. Planted chinook are three inches long, planted yearling lake trout, steelhead, and browns are larger but still have a gape (widest opening aperture of their mouths) that is too small to eat juvenile alewife. Example: I'll stick with a species that has the highest fidelity to eat alewife: chinook.  Chinook grow the most rapidly of any of the salmonines, feeding primarily on terrestrial insects  blown into the lake along the shoreline until late September/October, when the switch to YOY alewife, feeding on them near exclusively for the remainder of their life cycle.

Alewife are a pretty "r" selective fish, capable of popping a tremendous year-class from a relatively small breeding stock. The caveat; I said small, not nearly non-existent...

There is a spreadsheet I posted on this site that uses catch-at-age data and species specific bioenergetics data on food conversion efficiency to calculate a rough estimate value for each of the salmon and trout (salmonines) species in the current Lake Michigan fishery.

A multi-species stocking cut was warranted in 2012. It did not happen because LMC Committee members determined that they were not going to re-route or dispose of fish in the raceways in mult-year rearing cycles( lake trout are reared under Federal contract in Michigan hatcheries). Per the Decision Analysis Model; 100 hundred simulation runs for a twenty five year interval duration, yielded a 4% likelihood of an alewife stock that would fall below 100kt. via Option 4. This was three-fold lower liklihood of occurrence than Option 2, a chinook only stocking reduction, which is the option LMC chose to enact.

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Steeliebob

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #18 on: July 28, 2016, 01:06:52 PM »

I have fished for salmon in the straits area for about 30 years and have probably cleaned give or take 3000 salmon and have watched many get cleaned. In those 30 years and many pounds of salmon guts later I have yet to find a single alewife in the stomach of a salmon. If they eat all of these alewife why are they not showing up in stomach samples? I am going to say that of the planted fish survival is more likely 5 to 12% any lower and planting fish would not be worth the investment
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Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #19 on: July 29, 2016, 06:44:38 AM »

You might want to take a peak at ANY of the reports (as well as pictures) from people who catch chinook with alewife in their stomachs, currently, as well as in all past years. Thank you for illustrating the value of personal observation...
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Yooperdad

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #20 on: August 31, 2016, 05:16:47 PM »

If there can be some positive news, this might be a bit of it.

https://content.govdelivery.com/accounts/MIDNR/bulletins/160c574
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Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #21 on: September 01, 2016, 05:06:17 AM »

I think the GLFC's Lake Michigan Management Committee has to have their stocking recommendations finalized by the end of September, 2016 to alter  Fall egg-taking quotas for chinook.
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Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #22 on: September 01, 2016, 04:17:49 PM »

Courtesy of Michigan Sea Grant:

The Lake Michigan Committee (a working group consisting of agencies that manage the waters of Lake Michigan) developed a proposal to reduce Chinook salmon stocking by 62%. Since its development each agency of the committee has received consistent feedback from stakeholders that lake trout stocking reductions should be considered, along with the proposal and we should not reduce the full 62% of Chinook salmon. The committee also heard of angler interest to increase harvest opportunity for lake trout.

Below are proposals the Lake Michigan Committee has agreed to:

Regulations

    The states of Wisconsin, Indiana and Illinois will pursue an increase lake trout bag limit from 2 fish per day to 3 fish per day. This will align with Michigan's regulations of 3 fish per day in MM 6-8.
    Michigan will pursue a possession season of "open all year" for MM 6-8 to align with the states of Wisconsin, Indiana and Illinois.
    Michigan will also pursue opening drowned river mouth lakes that currently have a closed season.

Chinook Stocking Reduction Alternative

    A new proposal for a Chinook salmon stocking reduction is to only reduce stocking by 50% of current levels. The new proposal is described in the table below. Under this alternative proposal, Michigan's Chinook stocking would go from 560,000 to 300,000 -- a reduction of 46% from current levels.

State    Current    Proposed    Percent  New Proposal    Percent
Wisconsin    810,000    355,000    56%         425,000    47%
Michigan    560,000    200,000    64%         300,000    46%
Illinois    230,000    90,000    61%         120,000    48%
Indiana    200,000    45,000    78%         60,000    70%

Total          1,800,000    690,000    61.5%     905,000    50%


Lake Trout Stocking Reduction
The total lake trout stocking in yearling equivalents averaged about 3,190,000 in recent years. The proposal would reduce stocking to 2,540,000, which is about a 21% reduction in lake trout lake-wide. All reductions will be outside the 1836 Consent Decree waters until a plan for further lake trout reductions can be reviewed and approved by the consent decree Technical Fisheries Committee.

The lake trout reduction includes discontinuation of 550,000 fall fingerling lake trout (220,000 yearling equivalents) stocking that was approved by the Lake Michigan Committee in 2015 and implemented in 2016.

The Mid-Lake Reef Complex (Sheboygan, Northeast and Milwaukee reefs) will be reduced by 300,000 or 50%.

Second priority lake trout stocking sites outside consent decree waters will be reduced 100%. This includes Grand Haven (20,000), Holland (40,000), New Buffalo (20,000), Michigan City (40,000), Sturgeon Bay (80,000), Kewaunee (20,000) and Wind Point (50,000).

Future lake trout stocking changes will depend on negotiations with the 1836 Tribal Nations. The DNR will propose to reduce all second priority stocking sites from Grand Haven to the north including Ludington, Manistee, Pointe Betsie, Good Harbor, Old Mission, Grand Traverse Bay Shoal, Torch Lake and Elk Rapids. If that plan is approved, the DNR could redistribute some lake trout to areas that were reduced 100% to maintain nearshore fisheries.

The Marquette State Fish Hatchery rears about 49,500 lake trout for Grand Haven, Holland and New Buffalo. We will continue to stock those fish with New Buffalo receiving 12,500 and Grand Haven and Holland each receiving 18,500.

The Lake Michigan Committee will more formally include Lake Trout management in future stocking decisions to help achieve predator and prey balance in Lake Michigan and also meet rehabilitation goals.
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MAK

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #23 on: September 01, 2016, 04:25:55 PM »

Just received this by email:


Fast facts on Lake Michigan salmon and trout

August 29, 2016
By Dan O’Keefe
 

Fisheries managers issued a new proposal to reduce stocking of Chinook salmon and lake trout. Anglers should get the facts before deciding how to react.


Many anglers, charter captains, and community leaders along the shores of Lake Michigan are wondering how a reduction in Chinook salmon stocking might affect fishing and tourism. Some question the need for a stocking reduction, some believe that stocking of another predator (lake trout) should also be reduced, and many are reporting that this year’s fishing has been a big improvement over 2015.

In June, fisheries agencies issued a proposal to reduce Chinook salmon stocking in Lake Michigan by 62 percent. That proposal was recently revised to include a 50 percent reduction in Chinook salmon stocking and additional measures to decrease lake trout stocking by about 21 percent and increase lake trout harvest. The Michigan DNR will host public meetings on Sept. 7 in Ludington and Sept. 13 in South Haven to discuss details of the revised proposal and hear comments.

Before forming an opinion on the new proposal it is worth considering the latest science on the state of the Lake Michigan fishery.

Most Chinook salmon caught in Lake Michigan are wild

According to the U.S. Fish & Wildlife Service’s Great Lakes Mass Marking Program, wild-spawned Chinook salmon made up 71 percent of the Chinook catch for Michigan anglers in 2014-2015. In Wisconsin waters, wild Chinooks made up 53 percent of the catch.

Even ports that are not near spawning rivers rely mostly on wild fish

Grand Haven is a good example of a southern Michigan port that does not support natural reproduction. Volunteers with the Salmon Ambassadors program found that 74 percent of Chinook salmon caught in the Grand Haven area in 2015 were wild. More than 90 percent of the stocked fish caught in Grand Haven were stocked elsewhere.

Alewife are at a historic low

The USGS Great Lakes Science Center’s bottom trawl survey found that yearling and older alewife biomass density dropped to 0.14 kg/ha in 2015, the lowest since monitoring began in 1973. This does not mean that alewife completely disappeared from the lake, but it does mean that less food is available for predators in open water. Also, Age 8 alewife were once common, but no alewife over Age 6 were found in 2015 surveys.

Last year the fishery appeared to be on the brink of disaster

The Predator-Prey Ratio for Chinook salmon and alewife was 0.108 in 2015. This means less than ten pounds of prey per pound of predator in Lake Michigan, which is similar to Lake Huron before the collapse. Ecosystems cannot support such a predator-prey imbalance for very long. Although the situation may have improved this year judging by angler reports, the Predator-Prey Ratio is based on a variety of data sources that take time to collect and analyze. The ratio for 2016 probably will not be available until March of 2017.

Chinook salmon eat more prey fish than lake trout

According to Michigan DNR consumption estimates, lake trout consumption of prey fish rose from 14.9 kilotons (kt) in 2011 to 23.1 kt in 2015. However, Chinook salmon consumption is still higher than lake trout (33.1 kt). Anglers and biologists realize that lake trout are increasingly important in terms of their impact on prey fish, but Chinooks are still “kings” when it comes to bait consumption.

Lake trout do not eat more alewife than Chinook salmon

Chinook diet is around 95 percent alewife while lake trout diet is typically 60 percent alewife or less, so in 2015 Chinook salmon consumed over 30 kt of alewife in Lake Michigan while lake trout consumed less than 14 kt of alewife.

Lake trout are not entirely dependent on alewife

According to a recent USFWS stable isotope study, lake trout rely more heavily on offshore bottom-dwelling prey than Chinooks do. Sculpin and goby are examples of bottom-dwelling fish have been doing better than alewife since the invasion of quagga mussels and related food web changes.

Lake trout are not managed by the federal government

A federal agency (U.S. Fish & Wildlife Service [USFWS]) does rear lake trout in hatcheries, but does not ultimately make decisions regarding the total number of lake trout stocked in Lake Michigan. State and tribal agencies on the Lake Michigan Committee (under the auspices of the Great Lakes Fishery Commission) arrive at consensus on stocking decisions.

The 2000 Consent Decree does influence stocking, harvest, and management of a variety of fish species in 1836 Treaty waters. The USFWS is a party to the 2000 Consent Decree along with five tribes and the state of Michigan, and the USFWS is also a member of the Technical Fisheries Committee. The role of USFWS is to provide technical assistance. Management decisions are made by state and tribal governments.

Stocking in public waters of Michigan must ultimately be approved and permitted by Michigan Department of Natural Resources. However, lake trout stocking in northern Lake Michigan portions of the 1836 Treaty waters is required by the 2000 Consent Decree to reflect an “expanded commitment to lake trout rehabilitation” and avoid lowering the established lake trout harvest limit.

Lake trout stocking was already being reduced as of 2015

In 2015, the Lake Michigan Committee approved a lake trout stocking reduction of 550,000 fall fingerlings (220,000 yearling equivalents). This reduction is being implemented in fall of 2016 independent of any Chinook salmon cut or additional measures related to lake trout.

The role of science

No matter which side of the argument you are on, it is important to support your position with the best available information. All of the statements above are based on the best available scientific information – but scientists will be the first to point out that “best available” does not mean perfect. Science is always improving, and scientists are always looking for better ways to make sense of patterns in the natural world.

Understanding the best available science is only the first step toward good decision-making, but it is an important one. Science does not dictate or result in a specific decision, but it can inform us of the risk associated with different options. In this case, we face a greater risk of alewife and salmon collapse over the long term if we do not reduce stocking. In the short term, severe stocking cuts could have a noticeable effect on catches in some areas of the lake. Good science will help us assess the relative risks, but ultimately we must decide which risks are acceptable and which are not.

Michigan Sea Grant helps to foster economic growth and protect Michigan’s coastal, Great Lakes resources through education, research and outreach. A collaborative effort of the University of Michigan and Michigan State University and its MSU Extension, Michigan Sea Grant is part of the NOAA-National Sea Grant network of 33 university-based programs.

Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #24 on: September 01, 2016, 05:02:31 PM »

While Dan is skewing the evidence on the role of science...

 The stable isotope data indicate much of what Dr. O'Keefe states, with one important aspect/finding omitted. When Mat Kornis' group did the work-up, they obtained stable isotope "signatures" for both juvenile alewife and adult alewife. When Matt presented this information at the Lake Committees meeting at the annual Great Lakes Fishery Commission meetings, he stated that lake trout feed preferentially on the adult size fraction of the existing alewife stock, while ALL other salmonines, including chinook feed primarily on the more numerous juveniles size fraction of the open water alewife stock.  Why is this important?  Lake trout became numerically dominant in 2007/2008.  The year-class array of spawning age (Adult) alewife has been in constant decline since this interval. In 2016, the adult stock component make-up largely consisted of the 2010 year-class with some older remnant year-class individuals.

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Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #25 on: September 02, 2016, 07:59:35 AM »

 I did a cut and paste from the spreadsheet Randy Claramunt, MDNR Charlevoix Research Station biologist, populated via catch at age and bioenergetcis calculations of ALL Lake Michigan Salmonines (salmon and trout species) estimating annual consumption of alewife from Lake Michigan waters...

The values are in kilotons (Kt.) Pleast note that the chinook consumption value is a little over 33kt. while the lake trout value is a little over 23kt.  It would have been nice to have all the data, as well as the lake trout consumption trend data presented.

YEAR  chinook    Lake Trt. Coho     Brown Trt.   Steelhead
2010  8.90E+01 1.99E+01 4.30675 6.55631505 14.95679
2011  1.15E+02 1.49E+01 4.98257 5.12920191 16.14415
2012  81.9379 1.96E+01 5.21564 6.908536801 15.11261
2013  60.9657 2.05E+01 4.69976 6.98218062 12.28737
2014  35.7104 2.31E+01 4.39579 6.85772936 14.13571
2015  33.1225 2.31E+01 3.86131 6.50419715 11.18

I think it would have been valuable to include a discussion of the actual value of further reducing chinook plants as a stand alone action as well. Survivorship of planted chinook has been trending down over the last five years. I suspect the same thing is happening in Lake Michigan that has been occuring for Lake Superior planted chinook- they are released as a bolus of fish into the lake and are being eaten by lake trout feeding in the inshore waters. Cutting a stock component (hatchery origin chinook) 62% for a population of fish who do not survive to consume alewife is pretty ridiculous as well as being ineffective as a management tool.
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Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #26 on: September 02, 2016, 08:40:28 AM »

Sorry, I forgot one additional point...Sea Grant conducts an annual survey and mandatory creel report submission form the Charter fleet on Lake Michigan. I have not seen this discussed much anymore. They used to report their charters stratified by target species. The last time I saw this data reported, ten to twelve percent of the charter trips basin-wide were specifically targeting lake trout.

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h2owalker

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #27 on: September 04, 2016, 01:35:13 PM »

Dire wolf- I've asked this question to dnr and a friend at msu without being able to get an answer. I've looked at map of their trawling study and dates and think they were way off with their timin/temp/location to get accurate trawling data. Largely because of their predictions for this year. While I don't understand 95% of the above I do understand alewives movement from spawn to adult. A topic I haven't seen addressed anywhere with all their other data. For instance, does dnr say, ok sturgeon bay today we have 60deg temp and has been holding for 5 days now. Let's get up there and do a trawl while we know fry is in the area. Thoughts?
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Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #28 on: September 05, 2016, 08:23:57 AM »

The goal of the trawl sampling effort isn't to focus on catching the most alewife during sampling each year. It is designed to be a trend-through-time sampling effort: basically sampling the same depth interval array at each station in the same manner(tow time interval).  Recruitment to the gear occurs at age-two for alewife: this is the minimal age/size-fraction that these otter trawls begin to efficiently capture alewife.

There is a companion sampling effort that is also conducted using sonar emitting samplers, along with accompanying mid-water trawl geat that is towed to capture and verify the on-screen signal images. My old roomate from graduate school, Guy Fleisher, along with Ray Argyle, perfected the accuracy of the acoustic sampling gear and set-up the sampling scheme for this "secondary verification" effort, eventually leading to routine incorporation of the acoustic survey transect data into the forage fish abundance report in 2001. Each gear has its own drawbacks and sampling bias: acoustic tows are conducted at night, and better capture juvenile alewife numbers, since they are primarily pelagically dispersed. The transducer samples the entire water column, below its tow depth, which is 3-4M (the acoustic array is towed two meters below the bottom of the vessel hull during transect sampling). The otter trawling effort is conducted during daylight hours when alewife are concentrated near bottom. Additional tranect depths have been added beyond the old 110M depth cut-off point. Yes, the volume of water filtered as the trawl is ascending and descending through the water column, to and from the substrate is also added to the volume filtered estimates. (I think there are a couple of Youtube videos taken via GoPro camers fixed to the head-rope of the trawl as it is being towed across the bottom.)

As I stated earlier, both these trend-through-time sampling efforts generate collective estimates of both species densities and biomass for alewife, smelt, bloater chubs, deepwater sculpin, slimy sculpin, round goby and stickleback. A crude estimate of invasive Dreissenid mussels is also calculated from the collective samples. . These estimates, since they are obtained by standardize sampling techniques (same place, same depth, same gear deployed and fished the same time interval) are comparable on a year-to-year basis, enabling fishery managers a snapshot of the forage fish population array and trend, both collectively and on an individual specie-by-species basis.

Captured alewife are aged via otolith for annuli count analysis-the most accurate aging method.

Additionally, a 95% confidence interval is calculated for both species specific biomass and density estimates. You will see these adjacent the point estimate values in Tables in parentheses under the C.I. heading or as capped bars emanating from the point estimate values when the data are depicted via graphic array. Note: When these are not symmetric to the point estimate, some or several tow samples yielded higher than average or lower than average sample values. The more similar the or uniform through-out the sampling effort the individual sample values are, the shorter the C.I. bars are that extend up or down from the point estimate on the graph, the more consistent the sample values obtained at each sampling site are for an individual species. The "quick-and-dirty" way to gauge a point estimate's precision and accuracy is to interpret the C.I. estimate from the standpoint of: IF I conducted trawl sampling via the same effort, at these same stations, in this manner this year 100 times, I would come-up with an alewife biomass estimate or density estimate that falls within the CONFINES of the C.I. boundary scribed on the point estimate 95 out of 100 replications. Essentially, C.I. are a statistically derived means of testing the validity and accuracy of the estimate value obtained from a sampling scheme/effort.

A second statistical value is also calculated from the samples obtained via both trawl and acoustic transect sampling. It is the Relative Standard Error (RSE). Essentially, the higher the RSE values trend relative to each other (station to station), as well as on a year-to-year basis, the more "patchy" the distribution of the critter is.  RSE values on a station-to-station sampled basis have been climbing for several years...










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Dire Wolf

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Re: Altered course in Lake Michigan stocking in 2017
« Reply #29 on: September 05, 2016, 10:18:59 AM »

I forgot one point: Dave Warner now runs the acoustic sampling program. He took over in 2001 when Guy Fleischer transferred out to Washington State. Dave instuted a program that encouraged sport fisherman to email him coordinates and screen shots of large bait pods throughout the Lake Michigan basin, which he plotted through time this summer.

If you contact him at the USGS Great Lakes Science Center,Ann Arbor, Michigan ;he should be able to update you on what the results of that effort were/are.
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