Intersex prevalence and transcript abundance in Bass from Great Lakes tributaries and Pennsylvania

Session: Disease and Mortality in Fishes

Heather Walsh, USGS, [email protected]
Vicki Blazer, U.S. Geological Survey, [email protected]
Geoffrey Smith, Pennsylvania Fish and Boat Comission, [email protected]
Sean Rafferty, Pennsylvania Sea Grant College Program, [email protected]

Abstract

Intersex (testicular oocytes) has been identified in largemouth (Micropterus salmoides) and smallmouth bass (Micropterus dolomieu) from numerous sites in Great Lakes tributaries and the Susquehanna River basin.  In fish, intersex has been associated with endocrine disrupting chemicals in human wastewater, urban and agricultural runoff.  Typically, intersex prevalence in bass from Great Lakes tributaries has been found to be lower than bass from other drainages with significant agricultural land use.  For this study, male bass were sampled from Great Lakes tributaries in 2010-2012 and from the Susquehanna River basin in 2013-2016.  Intersex prevalence and severity was determined with histopathology and the transcript abundance of 40 reproductive genes was determined with Nanostring nCounter® technology.  The nCounter® produces quantitative data similar to qPCR and was used to identify transcript expression differences between intersex and non-intersex bass.  With this data, we can identify areas where endocrine disruption is of concern and identify associations with existing water chemistry data.  This information will be useful for management agencies to improve their understanding of where efforts should be focused to monitor and assess river conditions with the goal of reducing endocrine disrupting contaminants.