Brown Bullhead as an Indicator Species: Seasonal Movement Patterns and Home Ranges within the Anacostia River, Washington, D.C

Abstract

Elevated liver and skin tumor prevalence has been reported in brown bullhead Ameiurus nebulosus from the tidal Anacostia River, Washington, D.C. Movement data are needed to effectively use tumor prevalence as an indicator of habitat quality. We used ultrasonic telemetry to verify the residency of 40 adult brown bullheads (250–310 mm total length) in the Anacostia River during summer 2000, spring 2001, and fall–winter 2001–2002. During summer (10 fish tagged), fish remained within 500 m of their capture–release location, and their mean 95% minimum area polygon (MAP) and linear home ranges were 4.5 ha and 0.50 km. During spring (12 fish tagged), most fish traveled upstream of the capture–release location as water temperatures increased; they were approximately 1 km upriver by the end of the season. Mean 95% MAP and linear home ranges in spring were 19.7 ha and 2.1 km. During fall–winter (18 fish tagged), fish released in the river remained within 4.2 km upstream and 3.1 km downstream of their capture– release location, and their mean 95% MAP and linear home ranges were 15.9 ha and 2.1 km. In comparison, the 95% MAP and linear home ranges of fish released in Lake Kingman (a tidal freshwater impoundment of the Anacostia) were 5.8 ha and 0.58 km. No fish were located outside of the Anacostia River. We conclude that adult brown bullheads were resident in the system throughout the year.