Survey of intersex largemouth bass from impoundments in Georgia USA

Transactions of the American Fisheries Society
By: , and 



Intersex fish are increasingly being reported worldwide, primarily in rivers that receive treated wastewater, but few studies have investigated intersex in waters that do not receive wastewater. In a recent reconnaissance survey of intersex fish in North America, a high rate of intersex was reported for Largemouth Bass Micropterus salmoides in some southeastern U.S. rivers; however, the occurrence of intersex in impoundments has not been well described, especially on a statewide scale. Therefore, our objective for this project was to survey the occurrence of intersex Largemouth Bass in a variety of impoundment habitats across Georgia. Largemouth Bass were collected from 11 impoundments without direct municipal or agricultural wastewater inputs. Gonads from all male Largemouth Bass were evaluated for the incidence and severity of the intersex condition based on presence and arrangement of testicular oocytes. Overall 48% of male Largemouth Bass collected from impoundments were intersex, which was found in 9 of the 11 impoundments. Among impoundments, incidence of intersex ranged from 0 to 82% of the males sampled and surface area of the impoundment was a significant predictor of intersex incidence. Intersex fish were smaller than normal males, but population-level effects of intersex and causative factors of endocrine disruption in the impoundments remain unknown. The high incidence of intersex males in small impoundments demonstrates that the condition is not confined to rivers and suggests that factors other than those previously associated with intersex (i.e., municipal wastewater) may be involved.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Survey of intersex largemouth bass from impoundments in Georgia USA
Series title Transactions of the American Fisheries Society
DOI 10.1080/00028487.2013.824922
Volume 143
Issue 3
Year Published 2015
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Atlanta
Description 8 p.
First page 565
Last page 572
Country United States
State Georgia
Online Only (Y/N) N
Additional Online Files (Y/N) N