Ecology of elasmobranch cleaning stations and the effects of tourism activities in Bateman bay, Ningaloo Reef

Fish cleaning in the marine environment is a mutualistic interaction where one participant, the cleaner, removes parasites, scales and mucus from the other participant, the client at sites called cleaning stations. Most studies of cleaning station client communities have focused on ray-finned fish while elasmobranchs have received less attention. As wildlife tourism commonly targets cleaning stations as sites to swim with manta rays and sharks, there is a need to improve understanding of how elasmobranchs use cleaning stations. Additionally, little work has been done to assess if and how tourism has impacts on manta rays or their ecosystems. A resident population of manta rays forms the basis of a manta ray tourism industry Bateman Bay, Western Australia which uses manta ray and shark cleaning stations as sites for interactions. This makes Bateman Bay an ideal area to address the current gaps in understanding of elasmobranch cleaning station use and the effects tourism may have on manta ray cleaning behaviour. This study assessed the species composition and cleaning behaviours of the client community of the Point Maud and North Reef cleaning stations in Bateman Bay, Western Australia. Focus was given to the visitation frequency and cleaning behaviours of elasmobranch clients. The frequency of boat traffic and tourist presence at these sites and the proximity of manta ray tour interactions to cleaning stations was also studied. Using a remote underwater video system, 413 cleaning events involving 45 client species from 22 families including ray-finned fish, elasmobranchs and turtles were observed. Scaridae, Carcharhinidae, Labridae, Lethrinidae and Mobulidae clients contributed to 77.97% of the observed cleaning events. Differences in client community composition appeared to be driven more by season than site. Visitation rates and cleaning behaviours varied between elasmobranch families. Sharks and manta rays had the highest visitation rate for Point Maud in autumn, stingrays were the most frequent elasmobranch client at North Reef. No elasmobranch cleaning events were observed in winter. Manta ray cleaning events had the longest average duration, followed by stingrays and sharks. Manta rays were most frequently observed circling around cleaning stations while sting rays and sharks more commonly cruised past the cleaning stations. Boat traffic and tourist presence was more frequent at the Point Maud than North Reef. Of the observed tourist interactions, 16% occurred with cleaning manta rays. The behaviours of two manta rays before and during the interactions suggest that manta rays change their cleaning behaviours in response to tourists. This study showed that the Point Maud and North Reef cleaning stations supports a diverse range of clients. The high contribution of families valued for tourism and for recreational fishing to the client community at these sites suggests their function is important in maintaining the ecological, social and economic values of Bateman Bay. As such, protecting megafauna cleaning stations in Bateman Bay may help sustain the tourism industry and recreational fishing in the area. The results of the boat traffic and tourist presence data suggest that making the code of conduct a condition of tour operator licenses, which has been recommended in other studies, could assist in reducing the impacts of tourism on manta ray cleaning behaviours