This is the central local case. Researchers sampled four Choctawhatchee locations from 1997 through 2011, spanning the period before and after flathead catfish became established. A later 2024 survey provides an important new snapshot.
The invasion moved quickly
The long-term study documented more than 91 kilometers—about 56.5 miles—of range expansion in two years. At sampled locations, flatheads became the numerically dominant catfish within three years of first detection.
- Flathead catch rates increased significantly at all four long-term sites.
- Native spotted bullheads declined significantly at three of four sites.
- The flathead–bullhead relationship was negative except at the most recently colonized site.
The 2024 sampling result
A Florida Chapter of the American Fisheries Society abstract reports that FWC sampled 25 randomly selected Choctawhatchee sites in 2024. Flatheads were again the most abundant catfish collected, comprising about 61% of the sampled catfish community. No bullheads were observed or collected.
- Since 2005, flatheads reportedly ranged from 32% to 86% of sampled catfish.
- A 58-pound flathead was electrofished from the river in summer 2024.
Why it matters
The record shows a major community change after flatheads became established. It supports focused monitoring and removal discussions using Choctawhatchee data rather than relying only on examples from other states.