Date of Award

6-2022

Degree Type

Honors College Thesis

Academic Program

Biological Sciences BS

Department

Biological Sciences

First Advisor

Jacob F. Schaefer, Ph.D

Second Advisor

Jacob F. Schaefer, Ph.D.

Third Advisor

Sabine Heinhorst, Ph.D.

Advisor Department

Biological Sciences

Abstract

The Southeastern United States is home to high levels of aquatic biodiversity and was recently named one of the Earth’s biodiversity hotspots. Within this region, growing human populations continue to place pressure on aquatic ecosystems and the resident species. Darters (Percidae: Percina) represent a large proportion of the freshwater fish diversity in the region. However, for some species the fundamentals of age, growth, reproductive timing and effort, and ecology remain poorly understood. That said, understanding the timing, duration, and effort allocated to reproduction is vital to successful management of any species. The pearl darter, Percina aurora, has been recently listed as threatened due to its contracting range, likely due to anthropogenic pressure on the Pearl and Pascagoula River Systems. This species has been extirpated from the Pearl River, cutting its known distribution in half. Overall, little is known of pearl darter life history as surprisingly few reproductive adults have been captured. Thus, there remains a major knowledge gap in terms of the life history and reproductive ecology of this species.

The purpose of this project was to examine the age, growth, and reproductive ecology of pearl darters (Percina aurora) and other coexisting Percina species in the Pascagoula River Basin. Four Percina species were collected and the gonadosomatic index (GSI) was calculated over time to better understand the reproductive effort and timing. The Percina species collected included P. aurora, P. vigil, P. sciera, and P. suttkusi. The goal was to find the spawning window of each species as there may be some overlap with the pearl darter. This overlap could lead to larval competition for resources, placing another stressor on the threatened pearl darter. To better understand the age and growth of this species, growth was modeled using the Von Bertalanffy Growth Model (VBGM) based on size measurements of previously collected and vouchered pearl darter specimens throughout the range. Lastly, future directions of the research on the life history of the pearl darter were discussed.

Keywords: Pascagoula River basin, Percina, Reproduction, Life History, Threatened Species

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