Date of Award

5-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

College/School

College of Science and Mathematics

Department/Program

Biology

Thesis Sponsor/Dissertation Chair/Project Chair

Paul A. X. Bologna

Committee Member

John J. Gaynor

Committee Member

Robert S. Prezant

Abstract

Coastal development in estuaries is altering abiotic and biotic factors that encourage the propagation of populations of Chrysaora quinquecirrha. Extensive coastal development results in the proliferation of vinyl bulkheads and plastic floating docks in the Barnegat Bay estuary system. The purpose of this study was to determine if the increase in artificial vinyl substrate can affect density of C. quinquecirrha polyp recruitment. Oyster shell and vinyl settling plates were submerged at ten sites in Barnegat Bay for six, two-week periods during the summer of 2014. Polyps showed a greater affinity for settling on vinyl plates (0.337 polyps/cm2) than oyster shell settling plates (0.179 polyps/cm2, P < 0.0248). Settling density was greater for under hanging surfaces and C. quinquecirrha settled more often on vinyl undersides, (0.515 polyps/cm ) than oyster shell undersides, (0.233 polyps/cm2, P < 0.0001). There was no detectable difference between the settlement on vertical and top surfaces of either substratum. The densities of C. quinquecirrha medusa were also measured to determine if the presence of medusae was linked to the presence of polyps. A regression analysis revealed a significant positive relationship between the density of C. quinquecirrha medusae in the lagoon and the density of polyps on settling plates (r = 0.6660; P < 0.0187). Nudibranchs are potential predators of C. quinquecirrha polyps and were observed feeding on polyps in a laboratory setting. Nudibranch density was measured for each set of plates to determine if nudibranch predation affected the polyp density. A regression analysis did not show a significant relationship between the density of nudibranchs and the density of polyps (r = -0.1263; P < 0.8099], but the negative relationship suggests the potential that they could contribute to polyp reduction in some lagoons. Artificial substratum in the form of vinyl bulkheads and floating docks provides habitat for polyps and this increase in substratum is likely to enhance populations of C. quinquecirrha in Bamegat Bay, New Jersey. My results indicate that there are hotspots of polyp recruitment in Bamegat Bay and are related to the presence of reproducing adults in the area. Since the biphasic life history of this species requires hard, non-toxic substrate to overwinter and proliferate, the increasing use of these materials in coastal communities is bound to lead to greater numbers in the future. Potential solutions for limiting their proliferation include improving water quality, which could lead to greater competition for space or the introduction of polyp predators to interrupt the life history cycle leading to fewer adults being generated.

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