Jan, thanks for the explanation. That paints a very complete picture of the process. I live 1000 miles from any ocean, so how long they will live is interesting, as I know someone who has offered to send me some samples. I am worried about keeping them alive long enough to make the trip in a truck.
I bought a nice long handled dip net with a micromesh net last summer that I use to collect samples from the Mississippi river a couple miles from the house. It has proven to be a very valuable tool.