Characterization by enzyme electrophoresis of specimens of the genus Helicometra (Trematoda, Opecoelidae) from fish caught off the coast of northwestSpain

Species within the genus Helicometra are difficult to distinguish on morpho logical grounds alone, and are best discriminated with the aid of biochemic al techniques. In the work reported here, the electrophoretic mobility of m alate dehydrogenase isoenzyme of the Mdh-1 locus was used to characterize 3 75 individuals of Helicometra obtained from various teleost species (Anguil la anguilla, Conger conger, Gobius niger or Ciliata mustela) caught off the coast of northwest Spain. The results suggest that all specimens belong to only one species, probably H. fasciata. Observed genotype frequencies did not differ from those expected under the assumptions of Hardy-Weinberg equi librium, even when the genic frequencies differ considerably respecting a M editerranean population.