Two Decades of Advancement in Flathead Catfish Research

Abstract

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.

Accuracy, Precision, and Optimal Sampling Duration of Low‐Frequency Electrofishing for Sampling Reservoir Flathead Catfish Populations

“…Flathead Catfish are one of three ictalurid species in North America with large size potential and are of particular interest for trophy-sized angling (>864 mm TL; Vokoun and Rabeni 1999;Arterburn et al 2002). Where introduced, Flathead Catfish can negatively alter native fish communities due to their large sizes and piscivorous feeding behavior (Thomas 1995;Bonvechio et al 2009;Flowers et al 2011;Montague and Shoup 2021), frequently out competing native fish assemblages and establishing themselves as the apex predator (Brown et al 2005;Kwak et al 2006;Schmitt et al 2019). Because of their potential as a sport fish and the ecological harm they cause where introduced, accurate and precise sampling methods for assessing Flathead Catfish populations are a priority for fishery managers.…”

“…Despite the increase in research related to the management of Flathead Catfish over the past few decades (Brown 2007;Bodine et al 2013;Montague and Shoup 2021;Porath et al 2021), there are still significant information gaps, primarily because there is insufficient information about how to sample these species efficiently, accurately, and precisely (Brown 2007;Bodine et al 2013;Montague and Shoup 2021). Flathead Catfish are the least studied of the three ictalurid species with large growth potential (i.e., compared with Blue Catfish Ictalurus furcatus and Channel Catfish Ictalurus punctatus) and are in greatest need of gear performance studies (Bodine et al 2013;Montague and Shoup 2021).…”

“…Despite the increase in research related to the management of Flathead Catfish over the past few decades (Brown 2007;Bodine et al 2013;Montague and Shoup 2021;Porath et al 2021), there are still significant information gaps, primarily because there is insufficient information about how to sample these species efficiently, accurately, and precisely (Brown 2007;Bodine et al 2013;Montague and Shoup 2021). Flathead Catfish are the least studied of the three ictalurid species with large growth potential (i.e., compared with Blue Catfish Ictalurus furcatus and Channel Catfish Ictalurus punctatus) and are in greatest need of gear performance studies (Bodine et al 2013;Montague and Shoup 2021). Gear performance studies help quantify gear biases and the conditions under which precision and accuracy varies for specific sampling gears, allowing for the development of standardized protocols to minimize these biases and maximize sample precision (how reproducible versus variable the measurement is) and accuracy (how closely the data collected reflects what is actually there).…”

“…of Flathead Catfish data collected by LFE are unknown (Quinn 1986;Cunningham 1998Cunningham , 2004. Gear bias has been a consistent concern of Flathead Catfish managers and researchers for over two decades (Michaletz and Dillard 1999;Brown 2007;Bodine et al 2013;Montague and Shoup 2021). Quantifying a gear's bias is also important because when gear bias is well characterized, it can often be accounted for (i.e., corrected) to provide more accurate data (Pierce et al 1990;Bayley and Austen 2002;Shoup and Ryswyk 2016).…”

Evaluating Single‐ Versus Chase‐Boat Low‐Frequency Electrofishing for Assessing Flathead Catfish and Blue Catfish Populations in a Large River

“…However, low‐frequency electrofishing methods vary greatly among studies (Brown 2009; Bodine et al. 2013; Montegue and Shoup 2021) and are poorly described in fisheries methodological texts (e.g., Bonar et al. 2009; Zale et al.…”