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I was talking with Dave from the MDNR about some bait balls I marked in front of St Joe. I asked him about the Coho stomach contents of shrimp that people all over the different forums have been talking about. He chimed in with some info he said I could post on the forum there and I figured I would post it here also. Copy and pasted:

Tim

First, it looks like the forum folks have been discussing this. While it is possible this is bloody red shrimp (Hemimysis anomala), it is also possible that is is our native mysis (Mysis relicta). It is NOT Diporeia.

In order to tell the difference between the two mysis species, you need to look at the tai under magnification. See the pics on the web site nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=2627.

Coho have been known to eat these native mysids in Lake Superior and smaller coho (<12 inches) are known to to eat "bugs". Not sure of the size of the coho, but seems to me the larger ones in the past would probably have alewife in stomachs.

However, in the 1970s-1980s, at least one study Jude and others 1987) found that in spring, nearly half the large coho (I think they looked at over 300) had empty stomachs in spring.

Dave

Thanks again Dave and the MDNR!

There was some hope when the last invasive species to come into the lake - the bloody red mysis - that they'd fill the gap left by the disappearing diporea. From what I've heard, the bloody-reds are still barely hanging on. Apparently the shrimp the cohos are now eating are "possum shrimp" a native species. At least is shows the coho are adapatable to an alewife shortage.

One of the trout I caught yesterday on the shoals did have two alewifes in it's stomach so maybe some of the bait is heading back our way.

Hate to think we are going to have to switch to #22 hooks and figure out how to bait them with an eighth-inch long shrimp to get them to bite!