No abstract

No abstract

The morphology of the genus Salmincola is reviewed and its relationship to the genus Achtheres examined. Four species of Achtheres are transferred to Salmincola: A. coregonorum, A. extensus, A. strigatus, and A. corpulentus. The taxonomy of the genus is based on new and more reliable criteria, mainly on the details of the appendages. The structure of the second antenna and of the maxilliped, as well as the type of the bulla, are regarded as best recognition marks. All species of Salmincola are redescribed with these criteria in mind and the genus is recognized as having 15 species. A key to the species is given.The genus is divided into two subgenera. Subgenus Salmincola (Salmincola) is parasitic mainly on Salmonidae and is distinguished by the well-developed claw of the maxilliped. Subgenus Salmincola (Brevibrachia) is parasitic exclusively on Coregonidae and is distinguished by the vestigial claw of the maxilliped.Species of Salmincola fall into one of three categories: circumpolar, continental, and bicontinental. The first category comprises five species: S. carpionis, S. edwardsii (parasites of Salvelinus), S. thymalli (parasite of Thymallus), S. extensus, and S. extumescens (parasites of the coregonids). The continental species are subdivided into Palearctic and Nearctic. There are seven Palearctic species: S. coregonorum, S. stellatus, S. lotae, S. cottidarum, S. nordmanni, S. strigatus, and S. jacuticus. Only one Nearctic species is known, S. siscowet. Two species are bicontinental: S. salmoneus has a distribution straddling the Atlantic Ocean and S. californiensis is a Pacific species, found in North America and Asia.

Two samples of hake, Merluccius productus (Ayres, 1855), one taken SW off Vancouver Island, the other in the Strait of Georgia, were examined for muscle parasites. The offshore hake is infected with two species of Kudoa Meglitsch, 1947 (Myxosporea): K. thyrsitis (Gilchrist, 1924) and K. paniformis sp.nov. Only K. thyrsitis occurs in the Strait of Georgia. The new species is described and illustrated. Host–parasite relationships of both species are discussed and reasons for their differences in this respect are speculated upon.

The distribution of the parasitic copepod, Salmincola californiensis, on two size-groups (fry, fork length 3.2–5.8 cm; juveniles, fork length 10.2–27.0) of the sockeye salmon, Oncorhynchus nerka, is described. The existence of preferred sites for both groups is established. The distribution on the smaller fish differs from that on the larger in that on the former the copepods are most abundant in the region of pectoral and pelvic fins, whereas on the latter they are by far most common in the branchial cavity. Macroscopic and microscopic mechanical damage to the fish tissues, resulting from the presence and activity of the copepod, comprises injuries to gills, skin, muscle, and even bone. The "burrowing phenomenon" (failure on the part of the copepod to cease excavation of a completed cavity of implantation, resulting in perforation of body wall and penetration of the viscera) is reported upon for the first time.