Reestablishing a host–affiliate relationship: Migratory fish reintroduction increases native mussel recruitment

Ecological Applications
By: , and 



Co‐extirpation among host–affiliate species is thought to be a leading cause of biodiversity loss worldwide. Freshwater mussels (Unionida) are at risk globally and face many threats to survival, including limited access to viable host fish required to complete their life history. We examine the relationship between the common eastern elliptio mussel (Elliptio complanata) and its migratory host fish the American eel (Anguilla rostrata), whose distribution in the Chesapeake Bay watershed is limited, in part, by dams. We examined population demographics of E. complanata across locations in the Chesapeake Bay watershed, primarily in the Susquehanna River in the absence of American eels, and conducted experimental restocking of eels to assess potential impacts on mussel recruitment. Compared to surveys completed ~20 yr prior, E. complanata could be experiencing declines at several historically abundant sites. These sites also had extremely limited evidence of recruitment. Restoration of host fish improved recruitment, but results were not equivalent between stocking sites, indicating that host reintroduction alone may not be fully effective in reestablishing mussel populations. One site where eels were introduced (Pine Creek, Tioga County, Pennsylvania, USA) experienced an increase from 0 juveniles found during quantitative surveys prior to eel stocking to 151 (21% of individuals collected during quantitative surveys) E. complanata juveniles found four years after stocking. A second site (Buffalo Creek, Union County, Pennsylvania) experienced a more moderate increase from 2 to 7 juveniles found during 2010 and 2014 quantitative surveys, respectively. Continued examination of other potential interacting factors affecting recruitment, including water quality or habitat conditions, is necessary to target favorable sites for successful restoration.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Reestablishing a host–affiliate relationship: Migratory fish reintroduction increases native mussel recruitment
Series title Ecological Applications
DOI 10.1002/eap.1775
Volume 28
Issue 7
Year Published 2018
Language English
Publisher Ecological Society of America
Contributing office(s) Leetown Science Center
Description 12 p.
First page 1841
Last page 1852
Country United States
State Maryland, Pennsylvania
Other Geospatial Buffalo Creek, Pine Creek, Susquehanna River
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