The site fidelity of mummichogs (Fundulus heteroclitus ) in an Atlantic Canadian estuary: Implications for use as a sentinel species in environmental monitoring

Small-bodied fish were proposed for use as a sentinel species in environmental monitoring because they are usually more abundant and generally less mobile than large bodied fish, therefore increasing catch rate while also increasing their ability to reflect local conditions. The primary objective of this thesis was to describe the spatial and temporal movement patterns of mummichogs ( Fundulus heteroclitus) in a large river estuary and assess their usefulness as a sentinel species in environmental programs such as Environmental Effects Monitoring (EEM) for the Canadian pulp and paper industry. Experiments identified Visible Implant Elastomer (VIE) as the most suitable marking technique for mummichogs due to its high mark retention and lack of negative effects on growth and survival. Next, a two year mark-recapture study conducted along a ∼10 km span of the Miramichi River estuary concluded mummichogs in this region display distinct site-fidelity with the vast majority (96.6%) of specimens marked up to 16 months previously consistently found within 200 m of point of initial release from April-November. Subsequent stable isotope analyses (SIA) of samples from sites located upstream and downstream of multiple anthropogenic inputs into the same span of estuary confirmed the results of low mummichog mobility from the mark-recapture study. Simultaneously, these results demonstrated SIA was a useful method to determine the site-specificity of organisms along relatively small spatial scales (< 10 km) in areas receiving multiple anthropogenic inputs. With regards to mobility, these results add to the growing body of literature supporting the usefulness of mummichogs as a sentinel species in environmental monitoring programs for point source impacts in Canadian Atlantic estuaries.