Here is another study ewest. I can scan it and send it to you if you want. Just to warn you, the edges are a little fuzzy from when I originally photocopied it.
Behavioral interations between fish predators and their prey: effects of plant density. Jacqueline F. Savino* & Roy A. Stein
Ohio Fish & Wildlife Research Unit, Department of Zoology, The Ohio State University, Columbus, Ohio
Animal Behaviour
Volume 37, Part 2, February 1989, Pages 311–321
http://www.sciencedirect.com/science/article/pii/0003347289901206
