Direct observations of the association between a deep-sea fish and a giant scyphomedusa

Abstract

This is a report of evidence of a close symbiotic relationship between the scyphomedusa, Stygiomedusa gigantea and the fish, Thalassobathia pelagica. Images from remotely operated vehicles (ROV) were obtained of the fish swimming on and around the large scyphomedusa. This is the first ever documented symbiosis between an Ophidiform fish and a medusa.

Keywords:

• Symbiosis
• Bythitidae
• Thalassobathia
• Cnidaria
• Stygiomedusa
• Gulf of California, Mexico
• Range extension

Acknowledgements

We thank B. Seibel who kindly assisted us with the respirometry work. M. Murray generously X-rayed our fish specimen. C. Widmer (MBA) supplied gelatinous animals for the laboratory experiments. D. Cohen provided constructive comments on an earlier draft of this manuscript. We also thank the crew of the R/V Western Flyer and the pilots of the ROV Tiburon. We gratefully acknowledge the support rendered by the David and Lucile Packard Foundation.