Myxobolus aeglefini found in the skeletal muscle of poroushead eelpout Allolepis hollandi from the Sea of Japan

Abstract

A myxosporean parasite was found in the skeletal muscle of porous-head eelpout Allolepis hollandi (Zoarcidae: Perciformes) caught in the Sea of Japan. White pseudocysts, about 3 mm in size, were distributed randomly over the musculature, and gave a negative impact on the appearance of fish products. Fresh spores of the myxosporean were subspherical in shape, 12.0 (11.2-13.5) μm long, 11.0 (10.5-12.0) μm wide, and 7.7 (6.9-8.4) μm thick. Two almost equal polar capsules were 4.8 (3.9-5.4) μm long. A mucous envelope was present around the posterior part of spores. Histological observations revealed that the plasmodia were encased by the host's cartilaginous tissue. Based on spore morphology, tissue-preference and ecological characteristics, we identified the myxosporean as Myxobolus aeglefini Auerbach 1906. This is the first record of a myxosporean infection in porous-head eelpout.