Morphometric comparisons of the Gulf sturgeon (Acipenser oxyrinchus desotoiMitchill, 1815) in western and eastern population extremes

Abstract

Summary The Gulf sturgeon, Acipenser oxyrinchus desotoi Mitchill 1815, is an anadromous fish native to the Gulf of Mexico (GOM). This threatened species ascend northern GOM rivers ranging from the Pearl River, Louisiana to the Suwannee River, Florida. The drainage fidelity seen within this species coupled with the complex migration patterns create many unknowns concerning the functionality between drainages and size classes. Being a threatened species that cannot be sacrificed, morphometric measurements are difficult to acquire due to minimized handling times and non‐lethal data collection methods. Seven morphometric measurements of Gulf sturgeon were compared between western and eastern GOM rivers and multiple size classes (juvenile, sub‐adult, and adult). Principal Component, Discriminant Function, and Maximum Chance Criterion analyses were conducted and identified differentiating morphometrics and classified groupings among size classes and rivers of Gulf sturgeon. This morphometric approach has the potential to be used in parallel with molecular findings and should allow managers to identify sub‐populations for a variety of threatened and endangered species.

Growth Estimation of Western Population Segment Gulf Sturgeon Using Length‐at‐Age and Mark–Recapture Data

“…) and morphometric (Mickle et al. ) studies have distinguished distinct populations: a western population segment (WPS) composed of fish natal to the Pascagoula River (Mississippi) and the Pearl River; and an eastern population segment (EPS) comprising fish from drainages east of the Mobile–Tensaw River delta. Based on gill‐net surveys, Sulak et al.…”

“…Habitat alteration and fragmentation, river impoundments, and commercial fishing led to declines of Gulf Sturgeon and their subsequent listing as threatened under the Endangered Species Act in 1991. Molecular ) and morphometric (Mickle et al 2014) studies have distinguished distinct populations: a western population segment (WPS) composed of fish natal to the Pascagoula River (Mississippi) and the Pearl River; and an eastern population segment (EPS) comprising fish from drainages east of the Mobile-Tensaw River delta. Based on gill-net surveys, Sulak et al (2016) stated that populations natal to the Pascagoula and Pearl rivers have the lowest abundances across the extant range of Gulf Sturgeon.…”