Myxosporida of Macrourid Fishes from Southern California and Mexico

Abstract

Three species of macrourids yielded the following myxosporidans. From Coryphaenoides acrolepis (Bean) we recovered Ceratomyxa hokarari Meglitsch and Leptotheca informis Auerbach from the gall bladder; and Davisia coryphaenoidia sp. n., Myxoproteus californicus sp. n., and Sinuolinea magna sp. n. from the urinary bladder. The kidney of Coelorhynchus scaphopsis (Gilbert) was infected with Myxobolus mexicanus sp. n., and its gall bladder with Leptotheca informis. The gall bladder of Nezumia stelgidolepis (Gilbert) was infected with Myxidium coryphaenoidium Noble and a species of Ceratomyxa. Of the macrourid fishes studied to date, C. acrolepis possesses the richest fauna of myxosporidan parasites. The highest incidence of infection for this host was by C. hokarari (52% of 52 hosts), and the lowest incidence was by S. magna (6% of 17 hosts). Brief comments on multiple infections, parasite distribution, and host specificity are included. Little information is available concerning the role of parasitism in the biological organization of the deep ocean. This situation has largely been due to technical difficulties in obtaining suitable hosts from deep waters, and to inadequate numbers of parasitologists working in this area of research (Noble, 1973). We are presently engaged in an extensive study of animal parasites infecting fishes of the family Macrouridae, in hopes of gaining some understanding of the ecology of parasite-host relationships in a deep-sea environment. This paper deals specifically with the myxosporidan parasites inhabiting macrourids from waters off southern California and Baja California, Mexico. A study of Myxosporida from macrourid fishes of the North Atlantic, including a note on all previous reports of these parasites from macrourids, was made by Yoshino and Noble (1973). MATERIALS AND METHODS Collection data and autopsy dates are summarized in Table I. All autopsies were performed on specimens that had been fixed in formalin and preserved in alcohol, with the exception of Coryphaenoides acrolepis collected in April 1972, in which freshly extracted internal organs were fixed in alcohol-formalin-acetic acid and later transferred to 50% ethanol. Urinary bladders were found in only 17 of the 52 C. acrolepis examined in the present study. Removal of the gonads and urinary bladders by another investigaReceived for publication 13 March 1973. * This study was supported by NSF Grant GA 34144. tor, and the eating of these organs by sea birds before the fish could be recovered from freevehicle set lines, were the primary reasons for the absence of urinary bladders. Detailed examinations of the Myxosporida from these fishes were performed at the University of California, Santa Barbara, as described in Yoshino and Noble (1973). Dimensions of Myxosporida are given in microns.