Salinity and temperature influence on Scyphozoan jellyfish abundance in the Western Gulf of Mexico

Abstract

Increasing jellyfish abundance has been documented worldwide, though few studies have used standardized long-term data to examine jellyfish abundance across environmental gradients. Such datasets can provide an opportunity to analyze historical trends, document rates of change, and identify potential mechanisms of change. This study used standardized fishery monitoring data from Texas Parks and Wildlife Department from 1983 to 2013 to identify the abundance trends of three common scyphozoan jellyfish species in eight Texas bays that span environmental gradients. We hypothesized that jellyfish abundance would vary across the environmental gradient and jellyfish abundance would increase with increasing salinity and temperature. Although no strong abundance trends were observed, abundance peaks occurred in some bay systems. Salinity and temperature were found to be the most influential factors for jellyfish occurrence while dissolved oxygen ranked the lowest. Bell-curve functions generalized the relationship between salinity and scyphozoan abundance and identified abundance peaks at high estuarine salinities for A. aurita, and differing tolerance ranges for each species. Temperature relationships were generalized with a sigmoid function and highlighted tolerance at the highest water temperatures observed. These findings suggest that some jellyfish species may respond positively in Texas bays if climate change increases salinity and temperature regimes of estuaries.