Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences

First Advisor

Sale, Peter,


Biology, Ecology.




In this work, I compared several existing methods of studying piscivory (predation on fish) with a new method. The new method, timed-tethering, allows one to measure how long a tethered fish survives before being eaten, as opposed to the previous non-timed tethering technique, which measured presence/absence of tethered prey after an interval as an index of predation risk (Minello 1991). I used these new timed-tethers to study survival of juvenile french grunts, Haemulon flavolineatum. This work was done in Tague Bay, St. Croix, U.S.V.I. Several tethering studies were done, one study in conjunction with censuses to determine what patterns existed in piscivore and prey numbers. Results of the censuses showed significantly more juvenile grunts on the back reef, and more piscivores on the fore reef. Results of a survival analysis of the timed-tether data revealed that piscivory was more intense on the fore reef than the back reef. These results suggest that higher densities of piscivores may result in higher predation pressure. The other tethering studies I ran showed no evidence of a pattern in predation with respect to distance from the reef. One did find a significant difference in predation with time of day (more predation during the nocturnal period than during the diurnal, the reverse of previously held ideas about the effect of time of day). (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1996 .H2. Source: Masters Abstracts International, Volume: 34-06, page: 2295. Adviser: Peter Sale. Thesis (M.Sc.)--University of Windsor (Canada), 1996.