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I emailed one of our biologists here in Indiana concerning what I believe is the smaller than normal coho so far this spring. Mr. Dickinson was very prompt and gave me a thorough reply and I thought I'd share it with you after receiving his permission to do so. I encourage all of you if you have any concerns about any part of our fishery in Indiana, contact Ben Dickinson, he seems extremely knowledgeable and readily willing to share what information he can. This email address is being protected from spambots. You need JavaScript enabled to view it.. Keep the replies civil please.

Mike,
I’ve also noticed coho size has been down from my own fishing, and heard about it from a lot of anglers, both charter and recreational fishermen. Glad you mentioned the small kings, because I think some people have misidentified them as small coho. Mike Schoonveld mentioned that to me as well. So many small kings is somewhat unusual.

The factors that probably explain most of the small coho size is 2 harsh winters in a row (colder water = slower growth), plus consecutive poor alewife year classes means there’s not a lot of food for small coho to eat. Sure, they eat a lot of bugs, but those are only available April-October or so. They need alewives to eat over the late fall thru early spring period – and they need small ones. Cohos less than 14 inches long can’t eat 5 or 6 inch alewives very easily, so to get good fast growth, small coho really need lots of small alewives in the 1-3 inch range. We usually see really large coho in springs following large year classes of alewife from the previous summer – 2013 was a great example, we had a good 2012 spawn of alewives, and we had some large coho in the spring of 2013. I’m guessing that the 2014 year class of alewives was not very good, and we know the 2013 year class was poor as well.

There’s still time for lots of silver fish and bait to show up, and we’re definitely at the mercy of environmental conditions in Indiana. I’m hoping they show up and fishing picks up, but only time will tell. The outlook from the USGS preyfish survey reports is not getting better. There’s only 2 good-sized year classes of alewives (2010 and 2012) and we need a good spawn from them this year, or else things are going to go downhill sooner rather than later. It used to be that we found alewives up to 9 years old, in the last 3 years we’ve found very few older than 4 years old. This is extremely concerning, because it means there is less time for each generation of alewives to spawn before they die from starvation or predation. The other factor is that they are less nutritious than in the past – one study documented a 23% decline in energy density in alewives from 1980 to 2004, and that decline has likely continued. Which means that salmon need to eat more alewives to get the same number of calories, essentially.

Unfortunately it’s the same old story – quagga mussels have exploded in numbers (I attached a figure showing the mussel density of both zebra and quagga mussels from 1995-2010) and have a stranglehold on the lake. Quagga mussels are even worse than zebra mussels because they can live in much deeper water, which means they have colonized much of the lakebed that was unavailable to zebra mussels. They’ve also outcompeted and nearly eliminated zebra mussels from most areas of the lake. They are concentrating all the nutrients at the bottom of the lake, where they are largely unavailable to the food web. Until their numbers decline, Lake Michigan can’t support the number of baitfish it could before the quagga invasion.

The only silver lining is that although salmon are smaller this year, and slightly less fat, they are still nowhere near as skinny as Lake Huron fish were before it crashed. This suggests that we’re not on the verge of a sudden collapse by having too many salmon for the amount of bait – hopefully a sign that the 2013 chinook stocking cuts have avoided an imminent crash for the time being. Given the stocking cuts and what we know about alewife yearclasses and strength of Chinook yearclasses, this year I’d expect smaller coho, a bunch of shaker kings (1 year olds) not too many mid-size kings in the 5-10 pound range (2 year olds), and a decent number of 12 lb + kings (3 year olds). But I’ve been wrong before, and you know what they say about opinions/predictions!

Hope this is helpful and thanks for your email

Ben

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Scary stuff...as Dr Malcomb said in Jurassic Park. Life will find a way. ( I hope he was right ) I seen this article, www.fishdoubletrouble.com/New...t#.VTgaO_nF8ws

Thanks for that Mike.

Thanks for sharing the information Mike. I guess we will have to wait and see how much impact the cuts will have on the remaining forage base.

Yes thank you Mike - that was a great read.

Reel Fun, Can you attach the quagga/zebra density map he refrenced?

it was there - where did it go?

Nevermind its there - just being blocked by the network I am on for some reason.

We need to find find another fish species to eat those mussels

Gobies do to a certain extent. (small mussels) Drum do also. On another forum some guys were saying they should stock red eared sunfish. Apparently their whole diet is mussels but they stay shallower than 50 fow. I don't think there is a cure to 100% get rid of mussels. I know that they have a solution that they use on ponds and small lakes which eradicates only Zebra and Qug. mussels but they don't know how they could deliever or make it for such a large body of water.

Tmik34 wrote:

Gobies do to a certain extent. (small mussels) Drum do also. On another forum some guys were saying they should stock red eared sunfish. Apparently their whole diet is mussels but they stay shallower than 50 fow. I don't think there is a cure to 100% get rid of mussels. I know that they have a solution that they use on ponds and small lakes which eradicates only Zebra and Qug. mussels but they don't know how they could deliever or make it for such a large body of water.

I know of a couple of species that eat only mussels, and I would love to see the DNR start relocating or planting in the Great lakes. Sea Ducks...


They are already out there, but if the mussels population is that strong there should be plenty of food to host a larger population of sea ducks. Plus they are known to feed from 5 to 120 foot of water.

Maybe this is crazy talk, but maybe it's possible to do something similar to the Canada Goose program that was overly successful.