Intellectual Merit: The importance of fluxes across ecosystem boundaries is a characteristic of marine ecosystems that differentiates them from their terrestrial counterparts. From this viewpoint, any comparative analysis of marine ecosystems should address the patterns and degree of connectivity among ecosystems to be of highest utility. Here the investigators will conduct a suite of analyses that seek to quantify the sources, patterns and consequences of connectivity among 10 marine fishery ecosystems that together from the northwest Atlantic coastal shelf ecosystem. By conducting analyses in a hierarchical fashion with smaller ecosystems nested spatially within larger ecosystems they hope to identify scaling relationships in the ecological processes that characterize the dynamics of key species within these ecosystems. This work seeks to quantify the patterns and degree of connectivity among ecosystems in the Northwest Atlantic. Specifically, the investigators will conduct statistical analyses of empirical data from each ecosystem to quantify patterns in univariate, distribution and multivariate descriptors of their structure. They will also undertake time series analyses to describe relationships in the responses of different taxa and groups within each ecosystem. They will use the results of analyses conducted on the highly studied nearshore ecosystems as hypotheses to be tested on the somewhat sparser data of the offshore ecosystems. These analyses will delineate patterns of functional connectivity among ecosystems. They will also construct dynamic models of differing complexity to understand the principal consequences of the connectivity demonstrated in the first two objectives on ecosystem function. Models will include biomass dynamic and coupled predator-prey simulations that will consider the impacts of removals from the overall region globally and more specific patterns of localized spatial depletion.
Broader Impacts: Agencies, at all levels, are seeking to develop ecosystem-approaches to management (EAM) of fisheries in efforts to ensure long-term sustainability of the exploited marine resources and ecosystems. Central to EAM are Integrated Ecosystem Assessments (IEAs), which provide the societal, legal, and scientific basis to examine marine ecosystems at multiple scales -spatially, temporally, and jurisdictionally - and to coordinate the management of coastal ecosystem resources across multiple sectors. The open nature of marine ecosystems is a challenge for IEAs and EAM and particularly so for the Northwest Atlantic Coastal Shelf (NWACS) ecosystem. Key to management in this open ecosystem is assessment of the connectivity among key biota across space and time in the different regions. Here, the investigators will analyze ecosystem structure and function at a range of scales in a suite of interconnected regional ecosystems to support IEA development.
The world’s marine ecosystems are changing due to the impacts of climate change, harvest of natural resources, nutrient pollution, and contamination. In recognition of these threats, The Joint Subcommittee on Ocean Science and Technology of the National Science and Technology Council of the White House Office of Science and Technology Policy (JSOST) recommended a new course for the nation’s ocean policy. Within this framework, JSOST identified a near-term need of undertaking comparative analyses of the structure and function of marine ecosystems to improve indices of ecosystem health and the stewardship of natural resources. In support of this goal, our research team conducted a series of mathematical and statistical modeling studies to understand the sources, patterns and, consequences of connectivity among nine marine fishery ecosystems that together from the northwest Atlantic coastal shelf ecosystem from Cape Hatteras, NC to the Canadian border. Together these ecosystems support production of over 6.5 million metric tons of finfish and shellfish, provide $1.3 billion of economic benefit to local communities and provide recreational opportunities and direct experience of marine ecosystems for the 52.6 million people who lived in coastal states from Maine to Virginia as of 2003. Our analyses were conducted in a hierarchical fashion with smaller ecosystems nested spatially within larger ecosystems. By taking this approach, we worked to identify the key ecological processes that describe the growth and survival of valuable fish species within these ecosystems, and the relative importance of those processes when compared to human activities such as harvesting. In particular, my role in the larger project focused on three specific areas: 1) a data driven multispecies fish modeling project designed to quantify interactions (predation and competition for food) among 15 fishes in multiple areas - Gulf of Maine, Georges Bank, and southern New England; 2) a simulation modeling project based on fishes linked by a predator-prey relationship in the mid-Atlantic and structured to characterize the effects of spatial areas with low predation impacts (refugia) on the sustainability of harvesting; and 3) a simulation modeling project of a migrating predatory fish species frequently encountered in the Chesapeake Bay and nearby coastal areas that was designed to compare the relative roles of pulses of food production (higher prey availability) against harvesting on the rebuilding timeline from a depleted state. The first study, which is in the final stages of preparation for publication, showed convincingly that the strength of interactions among fish species varies considerably across spatial areas. This result brings to the forefront the idea that ecological processes involving fishes are highly variable across spatial areas, and that the boundaries of those areas generally do not match the jurisdictional borders of our current management system (e.g., state lines). The second study, which is also nearly ready for publication, demonstrated that spatial areas largely free of predation were vital to the future sustainability of prey species that experience both high levels of predation and harvest. Although not originally intended to do so, this result importantly highlights the need for thoughtful spatial management of marine ecosystems. And finally the third study, which is currently being reviewed for publication, showed that while higher food availability was beneficial to the predator, recovery time from a depleted state was far more related to harvest control than ecosystem processes. Agencies, at all levels, are seeking to develop ecosystem-approaches to management (EAM) of fisheries to ensure long-term sustainability of the exploited marine resources and ecosystems. Central to policy development are Integrated Ecosystem Assessments (IEAs) because they provide the societal, legal, and scientific basis for management. Our project directly feeds the needs of IEAs, and in addition to the aforementioned publishable manuscripts, our project also facilitated numerous oral presentations at national and international scientific conferences and the development of human resources in STEM education by supporting the completion of an M.S. and Ph.D. program and providing new and emerging research for that has been and will continue to be routinely incorporated into graduate student classroom instruction.
