Date of Award

Summer 2021

Document Type

Open Access Thesis

Department

Biological Sciences

First Advisor

Joshua Stone

Abstract

The cannonball jellyfish, Stomolophus meleagris, is commercially harvested throughout its range in the tropical and sub-tropical Americas, including in the South Atlantic Bight, where an estimated 4,000 tons (less than 2.4% of the estimated stock in South Carolina during the spring) are harvested annually. Like many Scyphozoan jellyfish, cannonball jellies have high interannual variability and little is known about the environmental drivers of their distribution and phenology. To better understand the ecology of this targeted species, we used fisheries-independent abundance data of cannonball jellyfish from 2001 to 2019 collected by the Southeast Area Monitoring and Assessment Program (SEAMAP) throughout the coastal zone of the South Atlantic Bight. Average biomass is highest in the spring off the coast of Georgia and lower South Carolina (south of Charleston), and the largest jellyfish occur during the spring months. The lowest biomass occurs in the summer months when smaller jellyfish occur. This could indicate that adult cannonball jellyfish occur offshore in the spring, move inshore toward estuarine habitats to release larvae, then juvenile cannonballs move out of the estuaries as they mature throughout the summer and fall, and finally the surviving adults are detected offshore again the next spring. The seasonal and spatial variability described does not appear to be connected to temperature, salinity, chlorophyll-a concentration, or river discharge, but is perhaps influenced by distance from estuarine habitats and wind direction. Interannual variability in biomass is evident in the cannonball jellyfish of the South Atlantic Bight, but no long-term trends or strong correlations with the aforementioned environmental parameters were detected. Further analyses remain necessary in order to pin-point the drivers behind the variability seen in the cannonball jellyfish of the South Atlantic Bight.

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