No evidence for seasonality in the ectoparasitic fauna of slimy mackerel, Scomber australasicus

Abstract

Fifteen (or sixteen) species of ectoparasites-6 monogeneans, 4 (or 5) trematodes, 2 copepods, 1 isopod, 1 cestode, and unidentified cysts -were collected from 428 Scomber australasicus individuals caught at Eden, New South Wales, Australia, between November 1988 and June 1992. Neither common nor rare parasites of slimy mackerel showed seasonal variation in abundance or prevalence. Only the copepod Brachiella magna occurred more frequently on larger (older) fish than smaller (younger fish). Two monogeneans (Kuhnia scombri, Pseudokuhnia minor), 2 didymozoids, and unidentified cysts occurred more frequently on smaller than larger fish. The intensities of the remaining monogeneans (Kuhnia scombercolias, Kuhnia sprostonae and Grubea australis), 1 didymozoid, 1 copepod (Peniculus sp.), the isopod (Ceratothoa imbricata) and a trypanorhynch cestode were not significantly correlated with fish length.