Zoosymposia 17: 141–158 (2020) ISSN 1178-9905 (print edition) https://www.mapress.com/j/zs ZOOSYMPOSIA Copyright © 2020 · Magnolia Press ISSN 1178-9913 (online edition) https://doi.org/10.11646/zoosymposia.17.1.13 http://zoobank.org/urn:lsid:zoobank.org:pub:0CF40724-A8DF-45C6-8472-3F383F7D4F0C An ongoing saga: Endemic branchiobdellidans (Annelida: Clitellata) on translocated commercial North American crayfish STUART R. GELDER Department of Biology, University of Maine at Presque Isle, 181 Main Street, Presque Isle, Maine, USA. E-mail:
[email protected] Abstract Over the last 130 years demand for crayfish has exceeded regional supplies around the world, so stocks, primarily from North America, have been imported to satisfy this need. These demands are human based and include gastronomy, sport fishing bait, food for rearing animals, educational aides, ornamentation in waterbodies, and more recently a significant increase in pet crayfish sales. The three most common commercial species from North America are Pacifastacus leniusculus, Procambarus clarkii and Orconectes limosus, although four other species are increasing in importance as they become more widely distributed. All of these crayfish in their endemic range have been reported to carry branchiobdellidan annelids. Therefore, when the crayfish are translocated, their ectosymbionts likely accompany them. Eighty-six potentially transportable branchiobdellidans are recognized in this paper, along with the distribution of six species known to have been translocated. Moreover, branchiobdellidans endemic to the translocation regions have adopted introduced crustacean hosts, which demonstrates that branchiobdellidan host species specificity is not as restrictive as many researchers believe. On the evidence to date, these translocated branchiobdellidans appear to have the same relationship and cause the same amount of damage, if any, as those on their endemic crayfish hosts.