Assessment of the Middle Mississippi River Channel Catfish Population

Abstract

Harvest regulations are important for fishes that are both commercially and recreationally sought after such as Channel catfish (Ictalurus punctatus) throughout the Middle Mississippi River. Monitoring total harvest and understanding Channel catfish population dynamics (i.e., recruitment, growth, and mortality) are crucial for managing a sustainable population. Total commercial harvest and current harvest regulations in the Middle Mississippi River have not recently been evaluated. Thus, we evaluated total commercial harvest reports from 1945-2012 along with commercial fishing effort, population dynamics for the Middle Mississippi River Channel catfish population, and simulated the effects of various length limits on the reproductive potential and yield per recruit of the Channel catfish population. Overall, total commercial harvest has drastically declined from 1990-2012, while commercial effort has remained relatively constant. We speculate overexploitation as a possible cause to the decline in harvest given relatively constant commercial fishing effort. We collected 501 Channel catfish from the Middle Mississippi River during spring, summer, and fall of 2012-2013. Channel catfish were weighed, measured, aged (via lapilli otoliths), and egg samples were collected for fecundity estimates to obtain population level information. We used the static form of the spawning potential ratio (SPR) and the yield per recruit model to simulate variable exploitation rates at three different length limits (e.g., 356 mm, 381 mm, and 406 mm). Our yield per recruit simulation modeling results identified that a 381 mm length limit would not lead to growth overfishing until exploitation rates were between ,50 and 70%. Furthermore, simulation modeling predicted that the SPR was not below a critical minimum conservative threshold of 20% until exploitation rates reached between 50 and 70%; therefore, the population appears to be sustainable under the current length limit of 381 mm, if exploitation rates do not exceed 50-70%.

Evaluation of Recently Implemented Harvest Regulations in a Data‐Limited Catfish Fishery with Bayesian Estimation

“…Values of A for the lower Ohio River stock of Channel Catfish were similar to those reported by Donabauer (2009) for the commercially exploited Wabash River but were generally lower than those found for the commercially exploited middle Mississippi River (Table 2; Bueltmann and Phelps 2015) and for the Missouri River, which does not support commercial fishing (Table 2; Goble 2011; Eder 2014). Estimates of F for the lower Ohio River stock were low and statistically indistinguishable from zero (mean = 0.04, CRI = 0.00–0.19) but are the first estimates for this system.…”

“…Channel Catfish in the lower Ohio River had an L ∞ that appears to be consistent with the L ∞ of other regional populations and grew at a similar rate (Table 2; Colombo et al. 2008; Donabauer 2009; Eder 2014; Bueltmann and Phelps 2015; Stewart et al. 2016).…”

“…2008), as anticipated based on inverse correlations between these parameters. Even with the faster growth rate, Channel Catfish in the lower Ohio River reach the 33.0‐cm minimum size limit at about the same age as most stocks within the region (Hubert 1999), and vulnerability to the fishery occurs after maturity (Bueltmann and Phelps 2015), unlike the Blue and Flathead catfish populations in the lower Ohio River. However, an assessment of fecundity and age at maturity for the lower Ohio River population of Channel Catfish is needed to evaluate vulnerability to the fishery and recruitment overfishing.…”

Smallmouth Bass Population Demographics in Missouri Ozark Streams and an Evaluation of a Statewide 305‐mm Minimum Length Limit

“…Yield-per-recruit (YPR) models and spawning-potential-ratio (SPR) models are common tools used to assess growth and recruitment overfishing. These models have been used to effectively assess sportfish populations (Goodyear 1993;Slipke et al 2002;Bueltmann and Phelps 2015).…”

Using Population Dynamics to Model Harvest Regulation Impacts to Channel Catfish in the Monongahela River, West Virginia

“…The SPR represents the ratio of eggs produced over the cohort’s life span under fished conditions to eggs produced under conditions of no fishing. Critical SPR values for Channel Catfish have been found to vary among regions (Bueltman and Phelps 2015) but typically range between 10% and 30% (Goodyear 1993; Clark 2002; Slipke et al. 2002).…”