Hydrogeomorphic Differences Between Proximate Rivers Affect Use by Large Predatory Fishes

David A. Blewett^1,*, Philip W. Stevens², Colin P. Shea², James C. Oliver³, and Eric R. Johnson⁴

¹Florida Fish and Wildlife Conservation Commission, 585 Prineville Street, Port Charlotte, FL 33954. ²Florida Fish and Wildlife Conservation Commission, 100 8th Avenue SE, St. Petersburg, FL. ³Department of Environmental Protection, 1843 South Tamiami Trail, Osprey, FL. ⁴Florida Fish and Wildlife Conservation Commission, 3900 Drane Field Road, Lakeland, FL. *Corresponding author.

Southeastern Naturalist,Volume 20, Issue 3 (2021): 477–497

Abstract
Resource managers can benefit from understanding how hydrology, geomorphology, and vegetation type affect fish populations and expectations of fishing quality at varying spatiotemporal scales. We used electrofishing to examine abundance and distribution of predatory fishes in 2 proximate rivers in southwest Florida for 4 years. We conducted a cross-site comparison to quantify relationships between habitat (e.g., geomorphological features, shore types, in-water structure), water conditions, and abundances of large predatory fishes. We found abundances of Centropomus undecimalis (Common Snook; euryhaline species) and Lepisosteus platyrhinchus (Florida Gar; obligate air breather) were comparable between the Peace and Myakka rivers, and low abundance of Micropterus floridanus (Florida Bass) was associated with low dissolved oxygen in the Myakka River. The lowest dissolved oxygen occurred just downstream of large in-stream marshes, where conditions become hypoxic following seasonal vegetation die-offs. Understanding how habitat availability and water conditions favor fishes within a waterbody will guide how interventions to improve fishing quality (e.g., stocking fish) can be successful or if angler expectations need to be adjusted.

Download Full-text pdf (Accessible only to subscribers. To subscribe click here.)