Egg hatching in the monogenean gill parasite Discocotyle sagittata from the rainbow trout (Oncorhynchus mykiss)

behaviour branchie branquias ciclo vital comportamiento comportement darkness ectoparasites fotoperiodismo freshwater fishes gills hatching helminthe helminths helmintos host parasite relations in vitro experimentation life cycle life history light regimes moco monogenea mucus obscuridad oncorhynchus mykiss ova ovule parasite parasites peces de agua dulce periodicidad periodicity photoperiodicity poisson d'eau douce rainbow trout regimenes de luz trout trucha truite