Bradley M. Richardson

• PhD - Forest Resources (Wildlife Fisheries and Aquaculture)
• Research Fish Biologist at Agricultural Research Service

Objective The myxozoan Henneguya ictaluri is the causative agent of proliferative gill disease (PGD) in Channel Catfish Ictalurus punctatus and hybrid catfish (Channel Catfish × Blue Catfish I. furcatus), which is a significant disease concern within the commercial catfish industry of the southeastern United States. Incidence of PGD occurs most fre...

Ictalurid herpesvirus 1 (IcHV1) is the most significant viral agent in U.S. catfish aquaculture. Little is known regarding the genetic stability and antigenic variability of IcHV1. Herein, the genetic and antigenic diversity of IcHV1 field isolates was assessed by restriction fragment length polymorphism (RFLP) analysis and serum neutralization ass...

Alternative protein ingredient Intestinal microbiota Brewers' yeast A B S T R A C T The use of corn fermented protein (CFP) can be a promising alternative ingredient to replace soybean meal (SBM) in aquafeeds, because of its attractive price and constant supply. In this study, the apparent digestibility of CFP was evaluated with channel catfish (Ic...

In the United States, catfish are primarily farmed in earthen ponds, resulting in an aquatic environment influenced both by management practices and natural ecological processes. Profiling pond water microbiota can be useful for understanding what conditions may lead to microbial communities associated with production issues and could inform manage...

Enteric septicemia of catfish (ESC), caused by the gram-negative enteric bacteria Edwardsiella ictaluri, is a significant threat to catfish aquaculture in the southeastern United States. Antibiotic intervention can reduce mortality; however, antibiotic use results in an imbalance, or dysbiosis, of the gut microbiota, which may increase susceptibili...

To prevent catfish idiopathic anaemia, diets fortified with iron have been adopted as a regular practice on commercial catfish farms to promote erythropoiesis. However, the effects of prolonged exposure of excess dietary iron on production performance and disease resistance for hybrid catfish (Ictalurus punctatus × I. furcatus) remains unknown. Fou...

Practical approaches that estimate farm-level use and efficiencies of major resources would measure both environmental and economic sustainability of aquaculture production along with providing inferences on improving both sustainability components. This study used U.S. catfish farm data to evaluate the economic sustainability of nine commercial ca...

Bolbophorus damnificus is a digenetic trematode causing significant economic losses within the United States commercial catfish industry. The indirect life cycle is complex, requiring piscivorous birds, aquatic snails, and fish to complete. With federal protections on many piscivorous birds and no FDA‐approved therapeutic treatment for trematode in...

Avian piscivores cause direct economic losses to the aquaculture industry through predation, as well as indirect losses through transmission of digenetic trematodes. Bolbophorus damnificus is a trematode parasite associated with significant losses in catfish aquaculture. The complex life cycle involves the American White Pelican (Pelecanus erythror...

Simple Summary Throughout the Great Lakes basin, infectious diseases likewise threaten wild and hatchery reared fishes, and often require management attention. The lake sturgeon (Acipenser fulvescens) is the only sturgeon species native to the Great Lakes, where it is the largest and longest living fish therein. Due to multiple known and unknown fa...

Rotenone application has been reported to cause significant declines in zooplankton populations with cladocerans and copepods being the most susceptible and possibly taking months to recover. Because copepods and cladocerans are preferred by catfish fry, rotenone application could have significant effects on nursery pond production. Effects of rote...

In the mid‐2010s, Edwardsiella tarda was reaffiliated into three discrete taxa (E. anguillarum, E. piscicida, and E. tarda), obscuring previous descriptions of E. tarda‐induced pathology in fish. To clarify ambiguity regarding the pathology of E. tarda, E. piscicida, and E. anguillarum infections in US farm‐raised catfish, channel catfish (Ictaluru...

Edwardsiella piscicida is a growing problem for catfish aquaculture in the southeastern United States, particularly in channel (Ictalurus punctatus) x blue (I. furcatus) catfish hybrids. Research has shown E. piscicida isolates recovered from farmed catfish in Mississippi form at least five discrete phyletic groups, with no apparent differences in...

Proliferative Gill Disease (PGD), caused by the myxozoan Henneguya ictaluri, is an important parasitic disease in US catfish aquaculture. Continuous exposure of Channel Catfish Ictalurus punctatus to the actinospore stage of H. ictaluri results in a severe inflammatory response at the gills, leading to morbidity and death. Previous work indicates c...

The ability of organisms to survive ingestion and digestion by their predators, or endozoochory, is a fascinating ecological phenomenon that can facilitate predator-mediated dispersal of prey and alter interaction strengths within ecological networks. However, the role of endozoochory in the context of invasive species is considered less often. Thr...

Characterising myxozoan taxa parasitising fish hosts in catfish aquaculture ponds is crucial to understanding myxozoan community dynamics in these diverse and complex ecological systems. This work investigated the myxozoan fauna of the western mosquitofish, Gambusia affinis, a common, incidental species found in catfish aquaculture ponds in the sou...

The bacterium Edwardsiella piscicida causes significant losses in global aquaculture, particularly channel (Ictalurus punctatus) × blue (I. furcatus) hybrid catfish cultured in the south‐eastern United States. Emergence of E. piscicida in hybrid catfish is worrisome given current industry trends towards increased hybrid production. The project obje...

A strain of atypical Aeromonas hydrophila (aAh) has caused issues within the channel catfish Ictalurus punctatus industry of the southeastern United States since 2009. These atypical pathotypes cause acute mortality events resulting in catastrophic losses, as opposed to more chronic mortality and lesions seen in typical infections of motile aeromon...

Monofilament gill nets have increased in popularity in recent decades and are often considered to be superior to multifilament gill nets; however, this claim is still contested by many researchers. Target species, habitat characteristics, and mesh characteristics can all affect the efficacy and selectivity of these nets. Increased angling interest...

The many advantages to using benthic macroinvertebrates in freshwater biomonitoring are now well known and utilizing them in water quality monitoring has become a common practice around the world. Their ubiquity, diversity, and sensitivity to water quality make them excellent indicators of stream health. A study has been performed to identify assoc...

Southern Brook Lamprey, Ichthyomyzon gagei, is a primitive, non-parasitic filter feeder that lives in sandy streams in the Southeastern United States. They experience three life stages: (1) ammocoete, (2) metamorphosis, and (3) adult. This study aims to assess the presence of Southern Brook Lamprey at nine sites within a small watershed, Panther Cr...

The ecology of many non-game fish species is understudied, thus little information is known about the life-history and population structure of diverse fishes. Very little is known about the spatial structure and abundances of Southern Brook Lamprey populations, and less is known about their early life-history and ontogeny outside of living for up t...

The southern brook lamprey (Ichthyomyzon gagei) is a primitive, nonparasitic, filiform fish that inhabits streams of the Southeastern USA. Little is known about the species, especially in their cryptic larval form (i.e., ammocoetes) which burrow into fine sediment. The presence of southern brook lamprey populations suggest good stream quality; they...

The Southern Brook Lamprey (Ichthyomyzon gagei) is a primitive, jawless, filiform fish that possesses two distinct life stages: larval (i.e. “ammocoete”) and adult. This species inhabits many streams of the southeastern United States and spends the majority of its life as an ammocoete. Adults are well studied, but burrowing behavior and unknown mov...