Meeting Abstract

P2-136   -   Effects of urbanization on life-history traits and hormones of Western mosquitofish Romero, EA*; Gabor, CR; Aspbury, AS; Texas State University; Texas State University; Texas State University Ear205@txstate.edu

Urbanization has led to the increase of impervious covering. These anthropogenic changes to the environment transform streams by altering channel morphology, increasing nutrients and contaminants, and altering hydrology which selects for more tolerant species in increasingly urbanized areas. However, little is known about the consequences of urbanization on freshwater fish. By analyzing the morphology, life-history traits and cortisol levels we can understand the coping mechanisms linked to the success of tolerant species in places of high and increasing land use conversion. The Western Mosquitofish (Gambusia affinis), is a live-bearing fish abundant in North America. We examined cortisol levels and life-history traits across six populations with different percentages of urbanization. Using water-borne hormones we measured cortisol release rates at baseline, stress induced, and recovery. We also counted and weighed embryos and egg for each individual to explore reproductive allocation and life-history trade offs. We found reduced stress response in fish from more urbanized areas as well as higher reproductive allocation, suggesting tolerant fish populations may cope with urbanization by flexibly altering both reproduction and hormones. These results provide information about the mechanisms affecting community structure in freshwater systems in urbanized areas.