Behaviour 2019
Interference of fish cleaning at anemone cleaning stations
Stephen G Ratchford. University of the Virgin Islands, St Thomas, VI, United States

Cleaning symbioses may have major impacts on reef fish populations, but little is known about the types of activities that interrupt or disturb cleaning interactions. I quantified rates and types of disturbance to fish cleaning centered around corkscrew anemones Bartholomea annulata and associated cleaner shrimp Ancylomenes pedersoni and Periclimenes yucatanicus. In >600 hours of video captured over 35 weeks in nearshore waters in St Thomas, USVI, I identified >2800 fish visits to anemones covering just 4% of the time and resulting in ~900 shrimp cleaning encounters. Given the potential predation risk to cleaner shrimp when they leave the safety of anemones to clean fish, it is not surprising that fish visits do not always result in cleanings. Shrimp cleaned fish only rarely when another fish was present. I documented >500 cases of interference by other fish potentially competing to be cleaned, as well as by fish feeding nearby or swimming by the anemone while a fish was posing to be cleaned. 200 additional cases involved damselfish, anemone symbionts and abiotic factors. The cleaning of fish by these anemoneshrimp appears to be rare, brief, and easily disturbed.