Have you guys ever noticed how the thermocline on the St. Croix appears alot more pronounced at certain times? Today was one of those days so we sent the Marcum camera down and ended up finding a massive cloud of bait just inside the thermocline at 45+ feet. Not sure exactly what they are but it was thick enough to read on the sonar at almost 50ft. Surface temp was 74.5, at 25fow it was 71 and it dropped fast after 40fow down to 61 degrees in 47fow. There were fish in the area too but nothing was biting…probably full already.
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St Croix River Thermocline
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September 8, 2011 at 3:14 am #993537
That’s dang cool. If that was in salt water I would be guessing krill or something similar given the density of the little buggers. I wish there was an easy way to ID them. Regardless… cool video.
September 8, 2011 at 3:34 am #993540Its hard to tell what it is but there are two distinct little critters in that cloud, some look like daphnia or something similar and the other long skinny ones could be some type of larvae hatch or a very immature fish or minnow. Either way it’s WAY too much competition for my bait!
September 8, 2011 at 10:14 am #993550Sure hope they aren’t silver carp larvae
The mass of the fish makes me think they must be shad larvae newly hatched from this year?
September 8, 2011 at 11:50 am #993560Very cool vid…some type of macroinvertabrate….crappies shouldn’t be too far I would think.
JP
September 8, 2011 at 1:23 pm #993585From our catfish biologist at the MN DNR:
Looks like the one of the guesses was correct. There are daphnia darting around in there. The other dense cloud looks like chironomid (midge) larvae. Here is a decent website that explains some stuff about chironomids. http://lakes.chebucto.org/ZOOBENTH/BENTHOS/xiii.html
I’ve heard of this occurring on depth finders before and hearing the explanation of a chironomid hatch. First time I have seen video of it though. Pretty cool.
Note new e-mail address is in effect
Joel Stiras
Metro Catfish Project Lead
1200 Warner Road
St Paul, MN 55106
651-259-5806September 8, 2011 at 1:30 pm #993589asian carp fry? that is actually pretty darn cool just goes to show there is lots of fish food in the river. nice work
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