Invasive Blue Catfish in the Chesapeake Bay Region: A Case Study of Competing Management Objectives

Abstract

Freshwater fishes have been introduced outside their native range to establish recreational fisheries, but management conflicts arise when such introductions also result in potentially harmful effects on native species. In this case study, we focus on Blue Catfish Ictalurus furcatus, which were introduced in the Chesapeake Bay region and are now considered invasive. In many tidal tributaries, Blue Catfish have increased dramatically in abundance, expanded into high‐salinity habitats (up to 21.8 psu), and negatively affected native species, prompting calls for the development of an effective management plan. However, management of this conflict species is complicated by multiple competing objectives, including control of population size, maintenance of trophy fisheries, and expansion of commercial fisheries for Blue Catfish. Seven management recommendations were advanced by the Invasive Catfishes Work Group to control the spread and limit the ecological impacts of Blue Catfish on native species. We highlight opportunities for addressing these complex management issues and guide our suggestions using results from research on invasive Blue Catfish ecology and population dynamics, as well as management of invasive species in general. A formal approach, such as structured decision analysis, is required to resolve conflicts among user groups and to address the wicked problem of Blue Catfish in the Chesapeake Bay region.

OUP accepted manuscript

“…The competitive advantages conferred by these characteristics suggest that blue catfish are likely to outcompete native species resulting in declines in abundance of native species via suppression or displacement. Indeed, observed declines in relative abundance of the congeneric native white catfish ( Ameiurus catus ) in Chesapeake Bay subestuaries during the past few decades may have resulted from exploitative competition with blue catfish ( Fabrizio et al , n.d. ; Schloesser et al , 2011 ).…”

“…Recent studies suggest that pre-exposure to starvation events often induces adaptive responses such as reduced rates of mass loss, reduced metabolic rates and lower costs of digestion during subsequent starvation events (reviewed in McCue et al , 2017 ). In tidal tributaries of the Chesapeake Bay and, more specifically, in the James River from where the experimental fish were collected, the densities of the fish are high ( Fabrizio et al. , n.d. , 2018 ; Nepal and Fabrizio 2020a ), and thus fish used in our studies may have experienced starvation prior to capture.…”

“…A primarily freshwater fish native to large rivers in the Midwestern USA, blue catfish has been introduced throughout North America to promote recreational fisheries ( Fuller and Neilson, 2020 ). During the 1970s and 1980s, blue catfish were stocked in the tidal freshwater regions of three rivers in Virginia but have since become established in all major tributaries of the Chesapeake Bay (Fabrizio et al , n.d. ; Schloesser et al , 2011 ). Owing to the range expansion, increase in relative density and abundance and potential negative effects on native fish and shellfish resources, blue catfish are now considered an invasive species in the region ( Fabrizio et al , 2018 ; Nepal and Fabrizio, 2019 , 2020a ; Schmitt et al.…”

“…Blue catfish are also of concern in coastal rivers and lakes throughout the Eastern USA, including Delaware, North Carolina and Georgia ( Homer and Jennings, 2011 ; Bonvechio et al , 2012 ). As such, resource managers are now developing policies and regulations to limit their dispersal, population size and potential trophic impacts (Fabrizio et al , n.d. ).…”

Reproductive Characteristics Differ in Two Invasive Populations of Blue Catfish

“…One highly successful invasive species in the Chesapeake Bay region is the Blue Catfish Ictalurus furcatus (Fabrizio et al. 2021, this special issue), the males of which guard nests. Native to large rivers in the Midwestern United States, the Blue Catfish is a large (>50 kg), long‐lived (>25 years) freshwater fish that was introduced into Virginia tidal rivers of the Chesapeake Bay during the 1970s and 1980s to create a recreational fishery.…”