Ergasilids have unique lifecycle: eggs hatch into free-swimming naupliar phase, which comprises six stages, followed by first to fifth copepodids preceding the adult. First nauplius 0.003 in (0.08 mm) in length, sixth nauplius 0.01 in (0.29 mm). Only adult female is parasitic, seeking and attaching to a wide variety of freshwater fishes. Female attaches to gill filament of host, using clawed antennae that penetrate host gill epithelium. One, sometimes two, generations during the spring and summer; the population survives over winter as adult females on fishes.
Was this article helpful?