Document Type

Article

Department/Program

Virginia Institute of Marine Science

Publication Date

10-2019

Journal

Canadian Journal of Fisheries and Aquatic Sciences

Volume

76

Issue

10

First Page

1808

Last Page

1818

Abstract

This is the accepted manuscript version of the article.

American eels (Anguilla rostrata) are infected by the non-native parasitic nematode Anguillicoloides crassus, which can cause severe swim bladder damage. We investigated epidemiology of A. crassus to better understand its population-level effects on American eels. Nematode prevalence, abundance, and intensity and swim bladder damage were quantified in glass eels, elvers, and yellow eels from the lower Chesapeake Bay and related to season of capture, river system, and total length. Age-variant force-of-infection and disease-associated mortality were estimated using a three-state irreversible disease model, which assumes recovery is not possible. Results showed glass eels have very low infection prevalence and severity compared with elvers and yellow eels. Nematode abundance varied by season, river, and eel length, whereas swim bladder damage varied by season and eel length. Nematode abundance and swim bladder damage were weakly positively correlated. Force-of-infection, based on swim bladder damage, peaked at age 2, and disease-positive eels had an estimated lower annual survival probability of 0.76 compared with disease-negative eels. Full understanding of American eel population dynamics will require broader knowledge of cryptic disease-associated mortality throughout North America.

DOI

10.1139/cjfas-2018-0136

Keywords

Anguillicola-crassus Nematoda; Swimbladder Parasite; Dracunculoidea Infection; Regression-Models; Paratenic Hosts; Chesapeake Bay

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