Hi Everyone! I'm new here, I found this thread while searching for information on how to collect Hemimysis anomala and thought I should come back and share my success now that I've found them. I breed seahorses, so I thought they may make a good food. I know that's not what you all would use them for but I thought you all might appreciate where and how to get them.
First, I'm a little slow on the uptake; I knew we had Mysis relicta (now Mysis diluviana) in Lake Michigan but I always thought they'd be much too hard to catch from shore. It wasn't until I had a seahorse that wasn't eating and I needed live mysis for that I stumbled across the article about Hemimysis anomala being in the great lakes.
Of course I had to go try and find it.
My first attempts with looking for swarms (supposedly common in late summer) and under piers did not work. I also tried blindly dip netting in dark places I thought they might be; under piers and along a break wall. This may work for some people, and it's one of the ways that NOAA has sampled them, but I have a medical condition that wears me down quickly, so I couldn't do that much so that might be why I missed them. I thought I'd include that so if anyone wanted to try that approach, it still might work.
The next attempts bore fruit. I looked at NOAA's sampling protocol guide:
http://www.glerl.noaa.gov/res/Programs/ ... ocols.html
And built the soda bottle trap. It wasn't exactly the same, but close enough. I found a pier at a park and baited the trap with squid and baby brine shrimp. The squid was used because it's supposed to be a natural attractant. I tied them off to the pier and left the traps overnight. The first time, someone messed with the traps even though I had written "Plankton Sampling Traps, please do not disturb" on them. I could see one being messed with, but not the second one so someone was being a jerk. But, the person that did it, placed them on shore with a few inches of water, and even so, I still managed to get some mysis! Somewhere around 20-30 between the two traps.
The next time I went, I brought 3 traps, and this time they were not disturbed. I caught around 100 this time. I had tried them at different depths, floating at 2ft, 4ft, and just off the bottom. The one that was just off the bottom appears to have had the best results. Though it was only one try, multiple tries would probably be needed to confirm this.
Right now, I'm keeping them in a 5 gallon bucket while I watch their behavior and decide what to do with them. I have the two groups in separate buckets. They are very light sensitive and do not like even small amounts of light. I haven't seen any young, though just recently noticed some gravid females. I don't know if they are cannibalistic or not; I've read that they're not as cannibalistic as other mysis, but not seeing any babies makes me wonder about that.
One thing I feel it's important to mention is that I'm not sure about the legality of collecting and owning these. Wisconsin has them on their prohibited list. I tried to find out the specifics of the law, and some parts say it's illegal to transport them period, others say it's illegal to transport them where they might accidentally or purposely be released into waterways. Still another part says that keeping invasive species as a pet is okay as long as there isn't a chance they'll be released BUT excludes fish and crayfish (but this is neither so?)? So I'm not sure. I decided to take the risk because these will never see anything outside a seahorses belly. But others should be warned.
You have access to Lake Michigan where a very interesting species of freshwater Mysis now lives. The species is called Hemimysis anomala and has been accidentally introduced from the Caspian sea. They would make perfect companions to shrimp. Here are some links to infos and videos (they are actually much nicer looking than it appears on the videos). The last video portrays the colors of H. anomala best, but you have to fast forward a little bit to get to them. The benthic shrimp in all the videos are the European/Mediterranean freshwater shrimp Atyaephra desmaresti:
) to feel happy (and not die on you). H. anomala obviously does not need a heater, but I'd say they should do just fine continuously at around 68-72 degrees. Only experience will tell. 
Remember, this is all part of your relaxation regimen. 