Fish-habitat relationships in Florida springs: Do submersed plants and filamentous algae influence the population structure and production of small-bodied fishes?
   William Pine, University of Florida

Abstract: The primary objective of this study is to evaluate whether differences exist in the composition, growth, and survival of small-bodied fish species associated with aquatic macrophytes (vascular plants) and filamentous algae in two spring-fed coastal rivers that have already exhibited signs of degradation, i.e. the Chassahowitzka and Homosassa rivers. Such differences would be indicative of tight linkages between specific habitat types and their associated faunal communities, supporting the FCWS management approach of protecting critical habitats to protect habitat associated species. A lack of evidence for strong couplings between the different habitat types and fish communities would be suggestive of functional redundancy, with obvious management implications. The results of this project will further our understanding of the role of submerged aquatic vegetation (SAV) in dictating the community structure of higher trophic level organisms. It will also provide resource managers insight into the broader ecological implications of shifts in SAV that extend beyond aesthetics and disturbance to human-related activities. Intensive throw trap sampling in discrete vegetative habitats will be employed to sample small bodied fishes. Catch composition and size distribution of individual species will be used in a modal length-frequency and Lorenzen survival function analyses to assess growth and survival patterns in each habitat type. Differences in population metrics will be tested using repeated-measures analysis incorporating a variety of spatial covariates to measure and account for spatial autocorrelation of samples and natural variation in habitat and fish distribution. Results of this project will fill several major information needs identified by FWC as part of the FCWS including: (1) evaluating whether differences exists in the composition, growth, and survival of small bodied fishes associated with aquatic macrophytes (vascular plants) and filamentous algae in spring-fed coastal rivers, (2) evaluating the functional role of filamentous algae in mediating population dynamics of small bodied fishes as compared to aquatic macrophytes, (3) begin to develop an understanding of the “ecological value” of filamentous algae vs. vascular aquatic macrophytes to aid in developing decision tools related to evaluating the ecological value of these habitats vs. human perceptions of their value.

Award Matching Funds Total
$133,314.00 $133,314.00 $266,628.00

Year Funded Starting Date Ending Date
2007 7/1/2008 11/15/2011

Location: Statewide