The exciting thing about science is we still have so much to learn about the natural world, new discoveries are being made all the time. Rita Mehta at UCSC has been studying eels, specifically their pharyngeal jaws (see a video here), which are a second set of jaws that help the eels eat larger prey. Recently MLML helped UCSC researcher Rita Mehta and others to determine how many California moray eels are in an area of Catalina Island, part of the channel islands archipelago. Further, they are interested in growth of individuals and movement. They had help from people at the National Oceanic and Atmospheric Administration (NOAA) with using Passive Integrated Transponder (PIT) tags, acoustic tags and acoustic receivers to address eel growth and movement.
UCSC researchers Ben Higgins and Leith Miller measure a California moray.
Using traps, eels would be raised to the boat then a series of body measurements and total weight were taken, they would be PIT tagged and released in the area of capture. If they caught an individual again who had previously had a PIT tag, they could use the body measurements from before and compare them to the current measurements to learn how much they grew in that time period.
Eels were caught and then brought to the boat for measurements using these traps.
To learn more about eel movement, a subset of eels had an acoustic tag surgically implanted into them. Acoustic receivers were deployed at each cove which would detect the surgically implanted acoustic tags in the eels, if they were nearby. They believe that moray eels may go out to feed during night but not much is known. In two weeks, with over 300 unique eels measured and PIT tagged, you could imagine how dramatic and important an impact they have on the ecosystem!
Acoustic receivers were deployed in each cove to aid in understanding moray eel movement.