Kazuya Nagasawa

A COLLECTION OF FISH LEECHES (HIRUDINIDA: PISCICOLIDAE) FROM JAPAN AND SURROUNDING WATERS, INCLUDING REDESCRIPTIONS OF THREE SPECIES

Leeches were observed incidentally on fishes in collections made from 1975 to 2006 in Japan and surrounding waters, or from mariculture facilities or public aquaria in Japan. Seven species of leeches in 7 genera were collected—Crangonobdella maculosa, Johanssonia arctica, Limnotrachelobdella okae, Platybdella olriki, Stibarobdella bimaculata, Taimenobdella amurensis, and Trachelobdella livanovi. The transfer of Calliobdella livanovi to Trachelobdella is supported, and Trachelobdella livanovi and Taimenobdella amurensis are redescribed based on new specimens. Stibarobdella bimaculata is synonymized with Stibarobdella macrothela based on eyes, tubercle patterns, and sucker size ratios. Taimenobdella amurensis, C. maculosa, J. arctica, S. macrothela, and P. olriki are reported for the first time from Japan. New hosts are reported for L. okae, T. livanovi, S. macrothela, C. maculosa, J. arctica, and P. olriki. Stibarobdella moorei was not collected during this study, but a well-preserved specimen collected in Japan was discovered in the Muséum National dHistoire Naturelle, Paris, France, and it allowed a redescription of this species. Stibarobdella loricata is synonymized with S. moorei based on tubercle patterns and the presence of papillae and a marginal fringe on the oral sucker.

New Hosts, Including Marine Fishes Cultured in Japan, of Limnotrachelobdella okae (Hirudinida: Piscicolidae)

Abstract The piscicolid leech, Limnotrachelobdella okae (Moore, 1924), was found to be parasitic on Japanese seaperch, Lateolabrax japonicus (Lateolabracidae), from Tokyo Bay and on kusafugu, Takifugu niphobles (Tetraodontidae), from the Sea of Japan in Yamagata, Japan. This species was also collected from bastard halibut, Paralichthys olivaceus (Paralichthyidae), and Japanese pufferfish, Takifugu rubripes (Tetraodontidae), cultured in the Seto Island Sea, Okayama, Japan. These 4 fish species are new hosts for L. okae. Based on a wide range of fish hosts of different taxonomic groups (11 species in 7 families from 6 orders) including the present 4 new hosts, L. okae apparently shows no strict host specificity.

A case of infestation by Limnotrachelobdella okae (Hirudinida: Piscicolidae) on Japanese Amberjack Seriola quinqueradiata cultured in Kyushu, Japan

2001年1月に大分県津久見市四浦地先の津久見湾で養殖されていたブリSeriola quinqueradiataの体表にヒダビルLimonotrachelobdella okaeの寄生を認めた。1984～1986年と1990～2007年の21年間に実施された大分県沿岸の海産魚の魚病診断で14,000尾以上のブリが検査されたが，本例が唯一のヒダビル寄生であった。また，寄生を受けていたブリは2000年12月に瀬戸内海中央部にある養魚場から搬入されたものであった。これらのことから，ヒダビルはブリの移動に伴って津久見湾に持ち込まれたと推測された。