A size‐based stock assessment model for invasive blue catfish in a Chesapeake Bay sub‐estuary during 2001–2016

Abstract

Management of biological invasions can benefit from estimation of population dynamics to understand population characteristics, predict population responses to control efforts, and assess invasive species impacts. Assessment of population trends can provide insights on the status of invasive populations and form the basis for feedback on prior management actions (Robinson et al., 2013).

Predatory impacts of invasive Blue Catfish in an Atlantic coast estuary

“…Total abundance for 2015 was estimated by Hilling et al (2023) as 5,825,787 (95% credible interval = 4,102,352-8,794,919), with fish less than 150 mm being most abundant (Figure 3). Estimated biomass via conversion of numerical abundance to weight was estimated as 1105.82 metric tons (95% CI = 839.79-1630.75).…”

“…Estimates of total population food consumption by Blue Catfish from the James River, Virginia, based on the product of Hilling et al (2023) abundance estimates converted to biomass and consumption‐to‐biomass ratios. Consumption in 2015 was estimated as 3997 metric tons (95% CI = 3037–5890).…”

“…The model integrates information from fishery‐independent surveys, commercial harvest, and Blue Catfish life history to estimate abundance by length‐class. Given that the statistical catch‐at‐length model estimated numerical abundance (i.e., numbers of fish), we converted abundance estimates to biomass based on the expected weight of “typical” fish in length‐class l in 2015 (Table S5 in Hilling et al 2023). Length‐classes were specified in the statistical catch‐at‐length model based on total lengths corresponding to 11 size‐classes (0–149, 150–249, 250–349, 350–449, 450–549, 550–599, 600–699, 700–799, 800–899, 900–999, and ≥1000 mm).…”

“…Length‐classes were specified in the statistical catch‐at‐length model based on total lengths corresponding to 11 size‐classes (0–149, 150–249, 250–349, 350–449, 450–549, 550–599, 600–699, 700–799, 800–899, 900–999, and ≥1000 mm). The specified typical lengths were generally the midpoints of the length‐classes, with the exception of the smallest and largest length‐classes, where median survey values were used (Hilling et al 2023). Given that the statistical catch‐at‐length model was fitted using a Bayesian approach, random sampling from posterior probability distribution of 2015 abundance estimates with replacement permitted inclusion of abundance uncertainty in the estimation of population‐level consumption.…”

“…No fish were collected in the 0–15‐cm length‐class in diet surveys, as they are selected against by electrofishing gears (Buckmeier and Schlechte 2009; Bodine and Shoup 2010; Hilling et al 2023). Consequently, we assumed diet composition for the species of interest examined here would be negligible due to gape limitations.…”