Comparative Mortality of Juvenile Channel and Hybrid Catfish Exposed to Bolbophorus damnificus Cercariae. (26th July 2021)

• Record Type: Journal Article
• Authors: Gunn, Mackenzie A.; Allen, Peter J.; Graham Rosser, T.; Wise, David J.; Griffin, Matt J.
• Is Part Of: North American journal of aquaculture. Volume 83:Number 4(2021)
• Page Start: 346
• Page End: 353
• Publication Date: 2021-07-26
• Subjects: Aquaculture -- Periodicals; Fish culture -- Periodicals; Fishes -- Physiology -- Periodicals; Electronic journals; 639.80973
• DOI: 10.1002/naaq.10202
• Languages: English
• ISSNs: 1522-2055

Abstract

Abstract: The trematode Bolbophorus damnificus (Digenea: Bolbophoridae) has caused significant economic losses since the late 1990s, with deleterious effects on production efficiency in farm‐raised catfish. Previous work has demonstrated that even mild outbreaks, which may go unnoticed by producers, can result in over 60% reduction in net economic returns. Although transmission rates in Channel Catfish Ictalurus punctatus and hybrid catfish (Channel Catfish × Blue Catfish Ictalurus furcatus ) are similar in controlled studies, anecdotal industry reports imply that the impacts of B . damnificus on hybrid catfish are less severe. In this study, mortality in juvenile Channel and hybrid catfish exposed to B . damnificus was evaluated in two discrete, replicated infectivity challenges. Mortality curves in Channel and hybrid catfish were consistent with trends previously established for B . damnificus in Channel Catfish, although in both challenges cumulative mortality was significantly lower in hybrids. All exposed fish presented clinical signs consistent with B . damnificus infection—namely lethargy, exophthalmia, distended abdomens, and metacercariae grossly visible below the skin. No mortality occurred and no parasites were observed in control fish. The biological and economic implications of these findings on catfish production are unknown but suggest that hybrid catfish are less susceptible to the deleterious effects and reduced productivity elicited by B . damnificus in Channel Catfish.