We sampled fish during the summer of 1999, in Caney Bayou on the campus of the University of Arkansas at Pine Bluff, Jefferson County, in order to study the feeding relationship between the western mosquitofish (Gambusia ajfinis) and the blackspotted topminnow (Fundulus olivaceus). We identified and enumerated the diet items of 56 blackspotted topminnows and 28 mosquitofish that were captured using electroshocking, seining, and dipnetting. Pooled diet items for each species were analyzed using a variety of approaches: percent of diet composition, frequency of occurrence, Levins' measure of diet breadth, and Morisita's measure of diet overlap. Twenty-one percent of mosquitofish and 8.9% of the blackspotted topminnow had empty stomachs. The mean number of individual prey items in mosquitofish stomachs was 2.5 (SD = 2.1), while the mean number of items for blackspotted topminnows was 72.5 (SD = 118.68). Detritus (37%), terrestrial insects (34%) and chironomids (16%) were the three major components of the western mosquitofish diet. Cladocerans comprised 96% of the blackspotted topminnow diets. The diet breadth for the western mosquitofish (0.51) was relatively broad compared to the blackspotted topminnow (0.01). Diet overlap between these species was low (0.01).
Neely, Allyson R. and Pert, Edmund J.
"Feeding Relationship Between Two Synoptic, Morphologically Similar Fishes, the Western Mosquitofish (Gambusia affinis) and the Blackspotted Topminnow (Fundulus olivaceus),"
Journal of the Arkansas Academy of Science: Vol. 54
, Article 14.
Available at: http://scholarworks.uark.edu/jaas/vol54/iss1/14