Although the meeting was cancelled due to concerns over Covid-19, a subset of the original intended presentations happened virtually and are recorded and put online.
You can view them here
www.glfc.org/2020-lake-committee-videos.php
They are all worth a watch, although note that the SWG/Predator Prey one is last year's data as this year's data was not completed before the meeting so I would skip that one if you are in a time crunch. That data should be rolling off the presses relatively soon I think.
Mass Marking
Prey Fish
Lower Food Web
Lake Trout Working Group Report
A few of the many things of note :
Alewife, smelt, and bloater all had terrible spawns in 2019. Near-zero and near record lows in the surveys for young of year of all three primary pelagic baitfish. Perhaps not well timed with the lakewide stocking increase that will result in more chinook smolts hitting the water in the next several weeks. NOT a good sign for the next couple years unless we get a bumper spawn this spring or the next.
Also, 2019 adult alewife biomass as measured by the acoustic survey was down significantly from a big increase in 2018, and the age structure remains very young. Only 10 years ago, alewife were routinely sampled up to Age 8. Now , almost 100% of the alewife in the lake are 3 years and younger. Not good when they don't sexually mature until Age 2. That means at best an alewife gets 2 chances to spawn before it gets eaten. And older fish are bigger and have much more reproductive capacity for spawning.
A positive sign is that although adult alewife decreased, adult bloater biomass continued to increase, which might have alleviated a forage crunch by the drop in alewife. In fact, it was the first time the acoustic survey had estimated more bloater biomass than alewife biomass. Overall the acoustic biomass estimate of all primary pelagic baitfish (smelt, bloater, alewife) was slightly above the long-term average. So, although some potentially troubling signs with alewife for the future it is not all doom and gloom and there is still lots of bait out there.
It appears obvious that despite the not great news on the alewife front, that predators and prey are balanced well: by and large, fish are fat and healthy. Many remarked on very small coho caught early this spring (almost certainly because of a poor 2019 alewife yearclass) but the 2 and 3 year old kings being caught right now are in great condition and are clearly finding enough to eat for now.
Another item to note is the lower food web presentation - there are some really great graphics and explanation in there showing how offshore productivity has cratered in recent decades, while the nearshore has not been affected as much. Intuitively that makes sense, as most nutrient input is nearshore now, with the lack of phytoplankton supporting the base of the food chain offshore. Offshore productivity has been siphoned off by mussels. Keep that in mind when we're seeing tons of bait nearshore (say out to 5-10 miles), that's because it's the most productive water in the lake, and offshore is more or less a desert in terms of prey fish productivity. Be cautious of extrapolating what you see in the nearshore to the entire lake, because resource distribution and fish distribution is very patchy and uneven.
The 2018 yearclass of chinooks looks like one of the worst wild reproductive years since the 2013 yearclass. Only 46% wild lakewide for the 2018 yearclass, compared to 68% wild for all yearclasses lakewide. Bummer for angling but potentially good for alewife, particularly since there was a bad 2019 spawn. Might be a lean year for chinook survival for the 2019 yearclass too, given the poor alewife spawn.
In news that is probably not surprising to anybody, lake trout wild reproduction continues to increase steadily, especially in the southern part of the lake. Many metrics for successful rehabilitation are met or exceeded down here. I suspect we will be over 50% wild by 2022 at this rate for the entire southern basin. And possibly over 55 or 60% in very far southern (say Chicago over to South Haven and south). Both from a combo of the lake trout stocking reductions that happened a couple years ago being finally detectable in surveys and angler catch, and because of nominal increases in lake trout reproduction. In my opinion it's time to start thinking about ceasing what little lake trout stocking is done in Illinois and the southern refuge and let mother nature do her thing.
VERY early to say this with confidence but Indiana knocked it out of the park in the first year of returns of tagged steelhead - our fish had double the return rate of the next best tag lot in aggregate. Most of this is probably because our shift to larger skamania steelhead resulted in better survival but also larger fish at Age 2, which might be more likely to be caught than a smaller fish. We'll have to get another 2-3 years of data before confirming if this trend is real or not. But promising early returns!
Lastly, there's a fair bit of uncertainty over egg takes and stocking due to covid-19. Our hatchery staff are working hard to get all the 2020 spring stockings done as scheduled. Many states have cancelled egg takes for lots of different species. With Michigan cancelling their winter run steelhead egg take, Indiana will have a production hole since we get our eggs from them. We'll be looking to fill that space with any surplus that the hatcheries have, which would be chinooks, skamania, and coho for this year. And hopefully things get back to normal soon
Stay safe and get after those kings that are showing up!
