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ORCID
N/A
Access Type
Open Access Thesis
Document Type
thesis
Degree Program
Wildlife & Fisheries Conservation
Degree Type
Master of Science (M.S.)
Year Degree Awarded
2016
Month Degree Awarded
September
Abstract
Beginning in the early 1600s, dam construction in New England obstructed anadromous fish access to spawning grounds during migration. As a result, anadromous forage fish populations have declined, which has impacted freshwater, marine, and terrestrial ecosystems. To determine the impacts of dams on anadromous forage fish and freshwater ecosystems, I used historical and current data to estimate population changes in alewives (Alosa pseudoharengus) from 1600-1900. A significant reduction in spawning habitat occurred in New England as a result of 1,642 dams constructed between 1600 and 1900, resulting in 14.8% and 16.6% lake and stream habitat remaining by 1900, respectively. In eight New England watersheds, this translates to an estimated cumulative annual loss of 30 B juvenile alewives available as freshwater forage and 538 M year 1, 2 and 3 alewives available as marine forage. The cumulative annual lost number of adult return spawners was conservatively 17 M fish, or 3,642 metric tons. Lost marine-derived nutrients from adult return spawners were 11 T phosphorus, 64 T nitrogen, and 410 T carbon. A comparison of predator fish growth and condition in alewife and non-alewife lakes showed that white perch (Morone Americana) and yellow perch (Perca flavescens) have higher condition in early summer in lakes with alewives. Predator growth rates (length-at-age) were significantly higher in early life stages (ages 1 and 2) when alewives were present, but significantly lower in late life stages (ages 3 and older). Results indicate a greater maximum length obtained by mature fish when alewives are absent, and an earlier age and length at maturity when alewives are present. These results indicate significant ecosystem impacts of lost anadromous forage fish, with bottom-up trophic effects across multiple time scales and biological processes. An ecosystem-based management approach should be used by inland and marine aquatic managers, and ecosystem connectivity and trophic interactions should be considered when managing migratory fish and prioritizing restoration goals.
DOI
https://doi.org/10.7275/8854734
First Advisor
Adrian Jordaan
Second Advisor
Allison Roy
Third Advisor
Michelle Staudinger
Fourth Advisor
Michelle Staudinger
Fifth Advisor
Eve Vogel
Recommended Citation
Mattocks, Steven R., "Ecological Consequences of Lost Anadromous Forage Fish in Freshwater Ecosystems" (2016). Masters Theses. 433.
https://doi.org/10.7275/8854734
https://scholarworks.umass.edu/masters_theses_2/433
Included in
Aquaculture and Fisheries Commons, Fresh Water Studies Commons, Natural Resources and Conservation Commons, Natural Resources Management and Policy Commons, Oceanography Commons, Other Life Sciences Commons, Population Biology Commons, Terrestrial and Aquatic Ecology Commons