Tagging Pacific Sea Nettle Jellyfish

February 2013

Tagging Pacific Sea Nettle Jellyfish

As we kicked off the New Year and the RRCT working groups were planning their new action plans, there was another project happening in the background, a collaborative effort. In February, the RRCT, the Fishtracker project, commercial fishermen and Samantha Zeman, Graduate Student of the University of Oregon, collaborated to tag two Pacific Sea Nettle Jellyfish with acoustic transmitters and track their movement patterns using the array of acoustic receivers established at the Redfish Rocks Marine Reserve. Here you will find what happened and how we did it.

One mild morning we all boarded the F/V Top Gun, captained by Jeff Miles. It was an early morning departure, as usual. As we were lowered from the crane and headed out to sea, we took time to photograph the jellies, take in the fresh sea air, and enjoy the purr of the Top Gun as she brought us into the Redfish Rocks Marine Reserve. Shortly, we arrived to the acoustic array. Relying upon Captain Miles’s knowledge of the sea, we made a determination of which way the currents were moving and found a desirable location to release the jellies back into the wild.

The jellies about to be released were collected just days before by a crew of commercial urchin divers on the F/V Mach I. They had heard this project needed some fresh healthy organisms, as the ones previously acquired were rather old and defeated. So, on a dive trip, a couple of days before we were to complete the jelly tagging project, the crew kept an eye out while harvesting their urchin. Happily, they were able to capture two good specimens and provide them to Samantha’s project!

After ensuring the transmitters were properly relaying their signals to a receiver that we had aboard the Top Gun, they were released into the array. The release locations were recorded by GPS. The rest of the day was spent replacing and servicing equipment of the array. On our return to the Port of Port Orford, we stopped by one of the receivers that were likely to have picked up the signals from the jelly transmitters to see if anything was recorded. As the data was downloaded, we found it to be a success! They were floating freely and transmitting there locations.

Two questions are usually asked when talking about this project. Why are you tagging jellyfish? And, How do you attach a tag to a jelly?

Samatha’s project was implemented to learn more about the movement patterns of the Pacific Sea Nettle jellyfish. However, this research is a part of a larger research initiative that is being investigated by Samantha’s professor, Kelly Southerland. Kelly is working to learn more about the Leather Back Sea Turtle and its dietary habits. The Leatherback’s have a soft beak and jaws, they feed almost exclusively on jellyfish, which are made of mostly water and are nutrient poor. Kelly is working to figure out how these turtles can possibly find enough jellyfish to sustain the dietary needs. Hence, Samantha’s part of this project is to find out what she can about the jellyfish the turtles feed on, in hopes that the jellyfish’s movement patterns may give some clues as to how sea turtles are able to find enough of them to survive.

The logistics of tagging jellies is rather genius, and yet simple. The transmitter is squeezed into a rubber tube. A zip tie is slipped in between the transmitter and rubber tube, which makes a secure connection. The zip tie is then attached to the jelly by a natural hole in jelly’s structure that is located under its bell. That’s it!

We would like to thank everyone who committed their time and energy to this truly collaborative project! It couldn’t have happened better or gone any smoother. Thank you!