ASPECTS OF THE REPRODUCTIVE-BIOLOGY OF THE CONCHA WRASSE, NELABRICHTHYS ORNATUS, AT TRISTAN DA CUNHA

The reproductive biology of the concha wrasse, Nelabrichthys ornatus, at Tristan da Cunha in the South Atlantic Ocean is described. Histolog ical evidence shows that the species is a monandric protogynous hermap hrodite. N. ornatus displays full permanent sexual dichromatism with a ll males occurring in the upper size classes of the population. Size s pecific habitat preference is described. Aspects of the mating system of the species resemble a lek although the possibility of mating site selection by females is not discounted. Spawning groups have a sex rat io of between 4 and 7 females per male.