This study used field data of echeneid and ectoparasite associations with free-swimming whale sharks ( Rhincodon typus ) and captured mako sharks ( Isurus oxyrinchus ) to test whether (1) echeneid presence was positively correlated with ectoparasite presence; and (2) the number of ectoparasites was negatively correlated with the number of echeneid fish. Data from whale and mako sharks do not support the first hypothesis whereas data from mako sharks yields support for the second hypothesis. The results indicate that echeneids do regulate the number of ectoparasites on at least some host species, but these benefits may be contingent on the echeneid species.
Mucientes, G. R., Queiroz, N., Pierce, S. J., Sazima, I., & Brunnschweiler, J. M. (2008). Is Host Ectoparasite Load Related to Echeneid Fish Presence? Research Letters in Ecology, 2008, 1–4. https://doi.org/10.1155/2008/107576