Biological studies on the hemoflagellates of Oregon marine fishes and their potential leech vectors

Of 2,122 marine fishes belonging to 36 species collected in thevicinity of Newport, Oregon, 541 belonging to 8 species were infectedwith hemoflagellates. Four species of trypanosomes and three speciesof cryptobias were found in offshore fishes, but no hemoflagellateswere observed in fishes from Yaquina Bay.Trypanosoma pacifica was found in 177 of 1,102 Parophrysvetulus, 3 of 84 Citharichthys sordidus, and 1 of 35 Lyopsetta exilis,and survived in 10 other species after intraperitoneal injection. Thehost-specificity observed in nature was probably the result of selectivefeeding by the leech vector, possibly Oceanobdella sp. or Johanssoniasp. Division stages of T. pacifica were observed in the fish host anddescribed. The growth rate of juvenile P. vetulus injected with T.pacifica was less than that of uninfected individuals for a 10 weekperiod, after which the growth rates of the two groups wereequivalent.Trypanosoma gargantua was found in 3 of 7 Raja binoculata andthe vector was shown to be the leech Orientobdella sp.Two unidentified trypanosomes were observed, one from 21 of1,102 P. vetulus, 24 of 303 Eopsetta jordani, and 6 of 61 Microstomuspacificus, and the other from 4 of 35 L. exilis.A small, active cryptobiid was found in 106 of 303 E. jordani,51 of 1,102 P. vetulus, and a similar but larger flagellate in 9 of 35L. exilis. After intraperitoneal injection flagellates from E. jordanidid not survive in P. vetulus, but did survive in other flatfishes;flagellates from L. exilis survived in P. vetulus, but not E. jordani,indicating the possible presence of two species, one in E. jordani andone in P. vetulus and L. exilis.A larger, sluggish cryptobiid was found in 134 of 1,102 P.vetulus.An extremely large cryptobiid, grossly different morphologicallyfrom previously described species, was observed in 1 of 5Scorpaenichthys marmoratus. The developmental cycle in the leechvector Malmiana sp. was described; the leech Trachelobdella sp. wasalso shown to be a potential vector.Leeches belonging to the following genera were collected duringthis study: Johanssonia, two species; Malmiana, three species;Trachelobdella, Oceanobdella, Orientobdella, and Ostreobdella. Ofthese, one species of Malmiana and one of Orientobdella were experimentallyshown to be vectors of hemoflagellates.