I'm pasting in the emails with Prof Tom Lauer at Ball State. You all can judge for yourselves.

The student author is now a fisheries biologist in Oregon, but she is out on medical leave after she broke her back in a helicopter crash doing a fish survey. I left a msg with her husband in the same office. I am removing the YP curves for now.



Dan
I haven�t measured the largemouth bass gape and couldn�t tell you how yellow perch relates. From your comments, you appear to be questioning our yellow perch measurements. Fair enough. Measuring a few hundred yellow perch and largemouth bass of the same size would provide you with your answer.
Tom Lauer

Thomas E. Lauer, PhD
George and Frances Ball Distinguished Professor of Biology
Director, Aquatic Biology and Fisheries Center
Department of Biology
Ball State University
Muncie, IN 47306
TX: 765-285-8825
Fax: 765-285-8804
Email: [email protected]

From: Nickolaus
Sent: Monday, April 21, 2014 8:43 AM
To: Lauer, Thomas
Subject: RE: Yellow Perch gape

Prof Lauer,
Below is a screenshot of the table upon which I based the plot. Yes, many say that gape is a theoretical maximum prey dimension. I seek the physical dimension of the YP gape, and am not considering prey size. The paper seems to say GHM is a perch gape measurement, but these equations indicate a YP gape larger than that of a LMB when compared to other literature.
Dan

Dan
You plotted the theoretical maximum of the prey species, not the actual ingested prey size. In general, most piscivores will consume prey up to 1/3 to � their length. The portion of figure 3 that you did not graph is the actual consumption size. I suspect when you eat, you could take a bigger bite. I also suspect you rarely, if ever, take a bite that fills your entire mouth (the theoretical maximum).
Tom Lauer


Thomas E. Lauer, PhD
George and Frances Ball Distinguished Professor of Biology
Director, Aquatic Biology and Fisheries Center
Department of Biology
Ball State University
Muncie, IN 47306
TX: 765-285-8825
Fax: 765-285-8804
Email: [email protected]

From: Nickolaus
Sent: Monday, April 21, 2014 7:33 AM
To: Lauer, Thomas
Subject: Yellow Perch gape

Good morning sir.
As the father of a BSU freshman, I was pleased to see a BSU paper on a topic I�ve been researching, namely piscivore horizontal gape. I own a pond South of Lake Monroe and have been gaining understanding in developing a stable ecosystem. I�ve gotten involved in a forum called Pond Boss that discusses pond management. I�ve been trying to catalog the gape data for different pond fish, both from academic papers and Pond Boss member measurements. I have found it very interesting but your data from Gape limitation and piscine prey size-selection by yellow perch in the extreme southern area of Lake Michigan, with emphasis on two exotic prey items, Table III has me puzzled. For the sake of discussion, I�ll add my current literature search plot. I did the calculations in mm and converted to inches- but you can see that YP end up above largemouth bass. We all know that isn�t the case, so I thought to seek your input on how I might have interpreted your paper incorrectly. I would expect YP to be around 9-10% GW/LT. If I could reach enlightenment on this quandary and find some smallmouth data, I�d be pleased.

Thank you kindly,
Dan Nickolaus