Dr. Stuart R. Gelder, Emeritus Professor of Biology at the University of Maine at Presque Isle, recently traveled to Japan to conduct research with one of his international colleagues and take part in an international symposium. Dr. Gelder is one of the world’s leading researchers of branchiobdellidan annelid (crayfish worms).
During his trip, he collaborated with his long-time colleague, Professor Akifumi Ohtaka, at Hirosaki University, Aomori Prefecture, in northern Honshu Island, before travelling on to Sapporo, Hokkaido, to attend the 20th International Association of Astacologists Symposium. Astacologists are people who study crayfish.
At Hirosaki University, he discussed branchiobdellidan projects that students were pursuing as part of their degree program, and presented a seminar to both students and faculty. However, the primary aim of the visit was to collect and describe a new species of branchiobdellidan that Dr. Ohtaka had discovered 16 years ago. The delay in publishing the species description stemmed from the difficulty in observing its internal organs, which is essential to justify that the worms are new to science. After a successful collection of Japanese crayfish, two worm specimens were found and the required details obtained. A manuscript naming the species after a local volcano has been submitted to the Japanese journal, Species Diversity.
Two years ago, Dr. Gelder was invited by Dr. Tadashi Kawai, Wakkanai Fisheries Experimental Station, Hokkaido, Japan, to write a chapter on branchiobdellidans for a book entitled Freshwater Crayfish: Global Overview, and edited by T. Kawai, Z. Faulkes, and G. Scholtz. This he completed with his coauthor, Dr. Bronwyn W. Williams, Southern Illinois University, Carbondale, at the beginning of this year.
Following the chapter’s completion, Dr. Kawai invited him to make an oral presentation at the International Astacology Association’s 20th symposium in Hokkaido, Japan. The symposium drew about 50 members from North and South America, Australasia and Europe in addition to Asia. Dr. Gelder’s talk was entitled, “Distribution of acceptable hosts by ectosymbiotic branchiobdellidans (Annelida: Clitellata)”.
His talk reviewed the distribution of branchiobdellidans on crayfish and on less well known hosts such as freshwater shrimps, isopods and crabs. Crayfish worms are not parasites but must deposit their cocoons on a live host for the embryos to grow and hatch. The mechanism and reason for such a phenomenon is unknown. The presentation was very well received and members urged Dr. Gelder to submit the information as a manuscript to the peer-reviewed journal, Freshwater Crayfish.