THE MICROHABITAT AND MORPHOLOGY OF GRUBEA-COCHLEAR ON THE GILLS OF MACKEREL FROM LYME BAY, SOUTHERN ENGLAND

The microhabitat and morphology of Grubea cochlear (Monogenea), a rare gill parasite of Atlantic mackerel (Scomber scombrus), were investiga ted for a sample of fourteen parasite individuals obtained from Lyme B ay, southern England. Grubea cochlear showed a preference for the inne r hemibranch of the fourth gill arch, this localization contrasting wi th that of the related and sympatric species Kuhnia scombri. The morph ology of G. cochlear in this sample differed slightly from some of the previously documented specimens, especially with regard to the number of small genital hooks and the relative size of the haptor. It is sug gested that geographical morphological variation may occur in this spe cies.