A Mortality Event Involving Endangered Pallid Sturgeon (Scaphirhynchus albus) Associated with Gyrodactylus conei n. sp. (Monogenea: Gyrodactylidae) Effectively Treated with Parasite-S (Formalin)

In January 2020, a mortality event was documented in endangered Pallid Sturgeon (Scaphirhynchus albus) at the Neosho National Fish Hatchery (Neosho, MO, USA). Moribund fish appeared emaciated, with hemorrhages on the fins and rostrums. Mortality steadily increased, prompting an investigation into the cause. No viral or bacterial pathogens were detected; however, a high number of the novel Gyrodactylus sp. was identified on the fins and body surface of the affected fish. Treatment of the parasites with a formalin product was effective, and mortality decreased. Herein, we describe the novel species Gyrodactylus conei using a combination of morphological and molecular data. Due to the listing of the host as an endangered species, the concept of parasite conservation is also discussed.