The Role of Connectivity and Spatial Structure on the Population Dynamics of Marine Fishes

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dc.contributor.advisorSecor, David Hen_US
dc.contributor.authorArai, Kohma Herberten_US
dc.contributor.departmentMarine-Estuarine-Environmental Sciencesen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2023-10-12T05:35:06Z
dc.date.available2023-10-12T05:35:06Z
dc.date.issued2023en_US
dc.description.abstractMigrations regulate population structure, which can play an important role in conferring stability at aggregate scales via asynchronous responses of population sub-components to perturbation; however, little is known about the importance of spatial structure in population persistence in fishes. My dissertation aims to explore the role of spatial structure on the population dynamics of marine fishes. Two species that exhibit different types of population structure were considered: (i) Atlantic mackerel (Scomber scombrus) in the Northwest Atlantic, comprised of two components that have distinct spawning regions off Canada (northern contingent) and the US (southern contingent); and (ii) striped bass (Morone saxatilis) in the Hudson River (HR), which exhibit early-life partial migration whereby a portion of juveniles remain in their natal freshwater habitats, while others migrate into higher salinity habitats. In Chapter 2, I used otolith stable isotopes (d18O/d13C) to understand contingent mixing of the Northwest Atlantic mackerel over two decades (2000–2019). Prevalent contingent mixing occurred within the US waters, indicating that the northern contingent may provide subsidies to the US mackerel fishery. In Chapter 3, I combined machine learning with otolith d18O isoscapes to predict the geographic origin of the Northwest Atlantic mackerel spanning four decades (1975–2019). Contingent mixing occurred over four decades, including the 1970s when intensive foreign fisheries took place in US waters. Nursery hotspots were detected within spawning regions, but shifted over time. In Chapter 4, for HR juvenile striped bass, I explored the influence of early-life conditions and environmental drivers on partial migration. Otolith chemistry uncovered four dominant early migration modes. Partial migration was associated with larval growth, albeit facultatively controlled by environmental conditions. In Chapter 5, I evaluated how HR striped bass early-stage partial migration influenced recruitment patterns to the adult population over a 3-decade span. As an outcome of partial migration, adults recruited from a variety of nurseries, which exhibited asynchronous dynamics in response to climate variables. Through a comparative analysis of two species that exhibit different types of population structure, I demonstrated how spatial structure can play key roles in the population dynamics of marine fishes, with implications for management and conservation.en_US
dc.identifierhttps://doi.org/10.13016/dspace/65rj-h0vx
dc.identifier.urihttp://hdl.handle.net/1903/30955
dc.language.isoenen_US
dc.subject.pqcontrolledEcologyen_US
dc.subject.pqcontrolledAquatic sciencesen_US
dc.subject.pqcontrolledEnvironmental scienceen_US
dc.subject.pquncontrolledAtlantic mackerelen_US
dc.subject.pquncontrolledFisheries ecologyen_US
dc.subject.pquncontrolledFisheries managementen_US
dc.subject.pquncontrolledOtolithen_US
dc.subject.pquncontrolledStable isotopesen_US
dc.subject.pquncontrolledStriped bassen_US
dc.titleThe Role of Connectivity and Spatial Structure on the Population Dynamics of Marine Fishesen_US
dc.typeDissertationen_US

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