Population demographics of American eels Anguilla rostrata in two Arkansas, U.S.A., catchments that drain into the Gulf of Mexico

Abstract

The goal of this study was to compare American eel Anguilla rostrata life history in two inland river systems in Arkansas, U.S.A., that ultimately discharge into the Gulf of Mexico via the Mississippi River and the Red-Atchafalaya catchments. From 21 June 2011 to 24 April 2014, 238 yellow-phase A. rostrata were captured in the middle Ouachita River and tributaries using boat electrofishing and 39 in the lower White River using multiple sampling gears. Most of them were caught downstream of dams in both basins (61%). Medium-sized A. rostrata ranging from 225 to 350 mm total length (LT ) were the most abundant size group in the Ouachita River basin, but they were absent from the White River. Mean LT at age 4 years (i.e. youngest shared age) was 150 mm greater for the White River than the Ouachita River basin. Anguilla rostrata appeared to have a greater initial LT (i.e. minimum size upon arrival) in the White River that allowed them to reach a gonado-somatic index (IG ) of 1·5 up to 4 years earlier, and downstream migration appeared to occur 5 years earlier at 100 mm greater LT ; these differences may be related to increased river fragmentation by dams in the Ouachita River basin. Growth and maturation of A. rostrata in this study were more similar to southern populations along the Atlantic coast than other inland populations. Adult swimbladder nematodes Anguillicoloides crassus were not present in any of the 214 swimbladders inspected. Gulf of Mexico catchments may be valuable production areas for A. rostrata and data from these systems should be considered as range-wide protection and management plans are being developed.

Survival and Habitat of Yellow‐Phase American Eels in North Carolina Tidal Creeks

“…It is possible that yellow‐phase American Eels in the southeast USA truly have lower survival rates than more northerly populations; however, Cox et al. () used a catch curve to estimate annual loss rates of about 30% in an Arkansas river draining into the Gulf of Mexico. Another explanation for lower loss rates in these other studies is the greater yellow‐phase eel sizes compared to those in our study (Hudson River: 260–700 mm TL; Chesapeake Bay: 213–647 mm TL; Arkansas: 332–803 mm TL; our mark–resight survival modeling: 188–406 mm TL).…”