ABSTRACT: The antipatharian black coral Antipathes fiordensis is endemic to south-western New Zealand, where most of the population biomass occurs in shallow water throughout a network of fiords and inlets. The planulae larvae of A. fiordensis arenegatively buoyant, weak swimming and short lived. These factors, coupled with hydrographic observations of restricted water movement in the fiords, suggest that larval dispersal and gene flow will be limited in this species, and that separate fiords mayrepresent genetically isolated populations. This study tests the hypothesis of limited larval dispersal in A. fiordensis by examining the genetic variation and population subdivision both within and among fiords. Allozyme electrophoresis at 10polymorphic loci revealed an unusual population genetic structure in A. fiordensis. Significant genetic variation was found among sites (mean F_ST = 0.046, p < 0.01), suggesting larval dispersal is restricted even at distances of10 to 15 km. Interestingly, most genetic differentiation occurred between sites within fiords (F_ST = 0.034), rather than among fiords (F_ST = 0.02) which is contrary to the pattern expected if the fiord populations werereproductively isolated. Furthermore, regression of gene flow with geographic distance showed no evidence of isolation-by-distance between populations (r² = 0.017), as might be expected in a species with limited larval dispersal. Asexualreproduction was apparent in populations of A. fiordensis, as evidenced by genotypic diversity ratios <1, as well as significant departures from random mating associated with a combination of heterozygote deficits and excesses at the majority ofsites. I propose that the atypical genetic structure observed for A. fiordensis in Fiordland represents a population that has not yet reached equilibrium due to a combination of the effects of recent colonisation, asexual reproduction and thepotential longevity of individual coral genotypes.