Hi Dave. Reasonable questions, but I'm not sure I can provide better answers. You are asking for reasonable explanations of what seems to be an unreasonable observation. :-) The problem is that I did those food habits samples every month -- we tubed their stomachs and released them. I've got to admit that I was surpised as well. I may not have been as surprised if it had been big aquatic insects. However, the story is even further from that. Most of those big crappies had a ball of zooplankton in their stomachs in most months. They were plump, and growing fast. It may not seem right, but it was. That's why I started my response right upfront saying that crappies eat fish prey, when available. After we did that study, we were reading papers and talking to various people, trying to figure out how it could even be possible. The zooplankton were big, I'm guessing most between 0.5 mm and 1.5 mm, which is typical in a predator-dominated fish community. However, these were 12 inch black crappies, with all that zooplankton in the stomachs. One crappie "expert" we found suggested that black crappies could somehow collapse their gill rakers to strain the zooplankton, but we never found any evidence to support that theory.
So, there you are. I can only report what we observed, and can't give a satisifying explanation. Sometimes with Mother Nature, things just are?? I don't know. :-)
Dave
