Anthropogenic activities are increasingly altering freshwater ecosystems, with rising specific conductivity serving as a widespread indicator of environmental stress. Changes in conductivity may be associated with shifts in life‑history traits that influence how species grow, reproduce, and persist under altered environmental conditions, shaping a species’ ability to adapt. This project aims to explore how ecological traits of freshwater fishes are associated with variation in specific conductivity across the Chesapeake Bay Watershed. We focus on two key life-history traits, maturity age and fecundity, to assess how species’ life-history strategies influence their responses to conductivity gradients, with the potential to incorporate additional traits in future analyses. Our primary goals are to (1) investigate species-specific abundance patterns across conductivity levels to identify thresholds at which fish species are no longer detected and (2) determine whether maturity age and fecundity exhibit trait-specific thresholds in response to increasing conductivity. We will analyze long-term water quality and fish assemblage data (1986 -2019) from the Chesapeake Bay compiled by U.S. Geological Survey. To quantify species‑ and trait‑level responses, we will apply Threshold Indicator Taxa ANalysis (TITAN; Baker & King, 2010) along with quadratic‑plateau and step models to identify conductivity thresholds beyond which sensitive taxa are unlikely to persist. We hypothesize that fish communities in high conductivity streams will be dominated by species with shorter lifespans and a greater number of offspring, reflecting earlier maturation and higher fecundity. Conversely, species with longer maturation times and lower fecundity are expected to exhibit stronger negative responses and lower conductivity thresholds compared to species with more opportunistic traits. By linking functional trait variation to environmental thresholds, this project provides a trait-based framework for assessing how freshwater fish communities may respond to environmental change in the context of specific conductivity. These findings may inform stream health indicators and conservation strategies, and can be extended to additional traits, such as spawning season and functional feeding guilds.