Cooperative Fish and Wildlife Research Units Program: Florida
Education, Research and Technical Assistance for Managing Our Natural Resources

Quantitative research evaluating the effects of non-native freshwater fishes on native species in Florida is lacking despite the importance of this information for management. To address this knowledge gap, we will conduct a pond study evaluating the effects of one of the most widespread genera of non-native freshwater fish, Tilapia Oreochromis spp. (Oreochromis aureus, Oreochromis niloticus, and their hybrids), on two ecologically and socioeconomically important native fishes, Largemouth Bass Micropterus salmoides and Bluegill Lepomis macrochirus. Introduced in the 1960s, Tilapia spp. have become widely established throughout peninsular Florida. Previous research on the impacts of high densities of Blue Tilapia Oreochromis aureus demonstrated reduced age-0 production, recruitment, and growth of Largemouth Bass. However, these studies were limited in that they only evaluated the effects of high densities of Blue Tilapia on age-0 Largemouth Bass production and growth. We aim to build on these studies by evaluating the impacts of both low and high density Tilapia populations on age-0 and age-1 Largemouth Bass and Bluegill in 0.4-ha ponds (n = 9). The proposed study site is located near the current latitudinal limit of established Tilapia populations in Florida, which makes it an opportune location to study interactions of Tilapia with Largemouth Bass and Bluegill given possible Tilapia range expansion and/or population growth in north central Florida and the panhandle due to climate change.