Assessing the Biological Control of Atlantic Bay Nettles (Chrysaora chesapeakei) by Nudibranchs: Research Project Summary
Date
2020-09
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Publisher
Trenton, N.J. : New Jersey Department of Environmental Protection, Division of Science and Research
Abstract
A multi-year study was conducted to assess nudibranch predation as a means of controlling Atlantic Bay Nettle (Chrysaora chesapeakei) and other cnidarian polyps, which can successively mitigate the production and abundance of adult medusae in coastal waters. Nudibranchs collected from Barnegat Bay and the Shrewsbury Rive demonstrated selective predation and consumption of C. chesapeakei polyps in laboratory and field settings, though several factors may influence their effectiveness in controlling populations. Laboratory studies indicate that while complete predation of polyps did occur, incomplete or partial predation of polyps was also common. Under the latter conditions, nudibranchs consumed polyp tentacles, but failed to consume whole individuals. Another extenuating factor in nudibranch control of polyps is predation by nudibranchs on sea anemones observed in choice experiments. In the laboratory, predation potential was investigated using bay nettle polyps and the non-native sea anemone Diadumene lineata, a co-inhabitant of the man-made structures preferred for settlement by C. chesapeakei. The results showed a significant predation preference for C. chesapeakei. However, nudibranchs may be limited in their ability to act as efficient predators on bay nettle polyps if D. lineata are present in high numbers. The presence of other cnidarian species comprised in the diet of wild aeolid nudibranchs was also assessed. Nudibranch cerata were collected and 16S rDNA sequences of cnidarian DNA amplified from grouped individuals. Results showed that cnidarian DNA was present in over half of the samples with positive identification of Obelia bidentata, Moerisia spp., and C. chesapeakei. While nudibranchs possess the potential to control C. chesapeakei polyps, substantial aquaculture of individuals would be needed to seed coastal communities sufficiently to act as an effective biological means of managing cnidarian populations.
Description
Prepared by Joseph Bilinski.
Keywords
New Jersey, Atlantic bay nettle, Chrysaora chesapeakei, Bay nettle, Nudibranchs as biological pest control agents, Sea nettle - Biological control