Two Decades of Advancement in Flathead Catfish Research

We summarized advancements in Flathead Catfish Pylodictis olivaris biology, fisheries, and management published from 1999 to 2021. Our goal was to highlight recent advancements in Flathead Catfish research and address information needs for this species to encourage future research. We identified and reviewed 140 papers from 33 peer-reviewed journals, 27 theses/dissertations, and 13 technical reports on Flathead Catfish over the 23-year period. Most studies focused on introduced Flathead Catfish populations, age and growth, movements, diet, sampling methods, and human dimensions of Flathead Catfish fisheries. The number of studies published on riverine Flathead Catfish populations was greater than the number published on reservoir populations, and many studied negative effects of populations introduced outside of the species' native range. Flathead Catfish are most commonly found in shallow (<3-m) locations with large woody debris or riprap and substrates with a hard bottom. Flathead Catfish movement studies identified three distinct migration periods: overwintering, prespawn/spawn, and late summer/fall, with little movement between these migrations. Flathead Catfish are typically lightly exploited (0-19% annual exploitation) and have typical (for a long-lived species) annual total mortality rates of 11-37%, ranging as high as 62%. Flathead Catfish are most commonly sampled using low-frequency electrofishing. Despite an increase in published literature on Flathead Catfish, information remains inadequate such that most state agencies do not follow a standardized protocol for sampling Flathead Catfish and information to guide management approaches for the species is limited. Minimal research on Flathead Catfish reproduction and spawning has occurred since 1999. Additional research is needed on these and other topics to provide information critical to managing this important species.