(The following is a short white paper we drafted for publication in a NOAA Technical Memorandum that will serve as the proceedings of a workshop that was hosted by the Mid-Atlantic Fisheries Management Council in December, 2010 on Habitat and Ecosystem Approaches to Management in the Mid-Atlantic Bight)
MARACOOS remotely sensed ocean data and several assimilation circulation models. |
However, the state of the art, Integrated Ocean Observing Systems (IOOS), now monitor and model the physical and primary production dynamics of the ocean at the broad spatial but fine time scales required to understand the ways water column processes affect the vital rates of marine organisms and dynamics of their populations. IOOS is an intergovernmental/inter-agency effort focused on the development of ocean observing and forecasting systems. IOOS themes range from public health and safety to marine operations and natural resource conservation. As part of the US IOOS program, partners in the Mid-Atlantic region along the US East Coast have developed a regional scale ocean observing network. The footprint of the Mid Atlantic Regional Ocean Observing System (MARACOOS=MARCOOS=MACOORA) stretches along 1000 km of coastline from Cape Hatteras, North Carolina to Cape Cod, Massachusetts and offshore to the continental shelf break. MARACOOS uses a multi-platform approach to characterize the fine scale structure and dynamics of the coastal ocean. The platforms include US and foreign satellites in space, a network of high-frequency (HF) radars deployed along the shore, and a fleet of robotic gliders flying beneath the ocean's surface (for more data see here). Satellites provide time series maps of surface temperature, chlorophyll A, and other ocean color products describing light absorption and backscatter. Ensemble clustering is applied to the satellite information to objectively identify and visualize water masses and the surface fronts between them. The HF radar network provides hourly surface current measurements from the edge of the continental shelf into estuaries. These current measurements can be processed to show near-real time and statistical forecasts of horizontal surface flows, upwelling and downwelling dynamics, and the evolution of surface fronts. Robot gliders that carry sensors measuring temperature, salinity, chlorophyll-A, and particle backscatter describe seasonal to inter-annual changes in the vertical structure of the ocean. Satellite, HF radar, and glider data are assimilated into an ensemble of numerical circulation models (UMD-HOPS, NYHOPS, ROMS) that are evaluated by comparing model realizations to field measurements. MARACOOS data and model forecasts provide spatially and temporally explicit descriptions of the physical forcing, flows of materials, and primary productivity that structures and regulates the mid-Atlantic Bight ecosystem. In addition to an extensive data archive, MARACOOS makes these data freely available in real time via Internet portals managed by trained operational oceanographers. Developments in high speed wireless communications and internet infrastructure now permit real time virtual collaboration between marine habitat and ecosystem ecologists in the field and operational oceanographers with expertise in IOOS data streams and forecasts. Access to IOOS data and expertise allows ecologists to easily consider processes in the water column as well as on the seabed in studies of the life history processes that ultimately determine recruitment and the dynamics of populations of ecologically and economically organisms in the mid-Atlantic Bight ecosystem.
Industry and scientific collaborators involved in finding a solution for the bycatch mortality of butterfish in the longfin inshore squid fishery. |
We have begun to extend IOOS our informed habitat studies in two directions. In a project recently funded by the NOAA/NEFSC Cooperative Network, we are collaborating directly with members of the Garden State Seafood Association to use the ecological knowledge of fishers to refine our habitat models in an effort to develop tools to reduce the bycatch of butterfish in the longfin inshore squid fishery. The goodwill required for this close collaboration between the fishing industry, government and academic scientists was developed in IOOS regional association meetings that serve as “neutral ground” for many stakeholders with diverse and sometimes competing interests in the services of the ecosystem.
Ongoing analysis of adult summer flounder abundance responses during autumn migration and spawning to features measured with IOOS remote sensing. |
In another project, we are using archived IOOS data along with NEFSC bottom trawl survey data of adults and egg collections from NEFSC MARMAP surveys made during the 1970s and 1980s to identify the characteristics of summer flounder spawning grounds in the mid-Atlantic region. Our preliminary analyses indicate that autumn spawning may be concentrated outside the mouths of several large estuaries where processes of nutrient enrichment from estuarine outflows and coastal upwelling, high phytoplankton productivity, and processes of particle concentration along water mass convergences may create pelagic habitats promoting the survivorship and growth of summer flounder larvae. Furthermore, we have been using MARACOOS assimilative circulation model nowcast and short-term forecasts to adaptively route surveys investigating habitat quality for fish larvae. On these cruises we have collected large numbers of summer flounder larvae that appear, based on estimates of larval age and particle tracking in surface currents measured with HF radar, to be derived from a specific spawning ground identified in the analysis of summer flounder spawning grounds described above. While this study is still in its infancy, we believe our IOOS informed approach that combines regional scale habitat analysis and modeling with adaptive process based field studies will allow us to develop broad scale habitat models that couple ontogenic habitats and important life history processes for this and other species in the mid-Atlantic region. This is just the kind of approach required for effective space based ecosystem management.
Habitat science in the service of ecosystem management could focus on processes that affect many species rather than just a few. Andrew Bakun described the triad physical of physical processes in his book "Patterns in the Ocean". We are finding that distributions of summer flounder adults during autumn migration and spawning and eggs appear to be associated with these processes and they are likely to be important to many species. |
We believe our IOOS informed approach to habitat science will be most useful for the development of tactical tools for ecosystem assessment and management. There are several pathways toward the development of habitat science in the service of ecosystem management in the region. The first of these is to develop single species models focused on ecosystem keystone species indentified in ecosystem modeling efforts in the Northwest Atlantic 3,4. The rational behind this an approach is that the identification and conservation of habitats maintaining the resilience of ecosystem keystone populations should be translated across a level of ecological organization to promote the resilience of the ecosystem as a whole. By resilience we mean the tendency of populations and ecosystems to return relatively rapidly to healthy states following significant perturbations 5. One potential flaw with this approach is that rapid changes in climate are producing rapid changes in the distributions of animals, particularly in regions of faunal transition like the mid-Atlantic Bight 6,7. If this is the case, the identity of ecosystem keystones may also be changing and thus targeting at a few individual species could fail to meet the goal of promoting ecosystem resilience. What is most intriguing about our study of summer flounder spawning grounds is that the hydrographic processes and structures we have identified that may promote nutrient enrichment, concentration, and larval delivery are the same “triad” of processes that appear to define important spawning grounds for pelagic species in the eastern Pacific Ocean and Mediterranean Sea 8,9. Thus, we may be able to shift focus from habitat studies of individual keystone species, toward investigations of “keystone habitats” where physical and biological processes in the water column and on the seabed promote the survival of critical life history stages of many species rather than just a few. This approach focused on habitat processes will be essential if the ecosystem is changing rapidly with climate change. No matter what approach we take, habitat science in support of ecosystem assessment and management will require close, honest and open collaboration between physical and chemical oceanographers, habitat ecologists and ecosystem scientists, as well fisherman who arguable have the most intimate and practical understanding of the ecosystem as a whole.
1 Manderson J, L Palamara, J Kohut, MJ Oliver. (in review) Using an ocean observatory to identify habitat associations of species with different vertical habitat preferences in the coastal ocean.
2 Palamara L, Manderson J, J Kohut, Oliver MJ & J Goff (in review) Improving Models of Covariation Between Marine Communities and their Habitats by Incorporating Pelagic Features Captured by Coastal Ocean Observatories
3 Link J, Overholtz W, O'Reilly J, Green J, Dow D, Palka D, Legault C, Vitaliano J, Guida V, Fogarty M, Brodziak J, Methratta L, Stockhausen W, Col L, Griswold C (2008) The Northeast U.S. continental shelf Energy Modeling and Analysis exercise (EMAX): Ecological network model development and basic ecosystem metrics. Journal of Marine Systems 74:453-474
3 Link J, Overholtz W, O'Reilly J, Green J, Dow D, Palka D, Legault C, Vitaliano J, Guida V, Fogarty M, Brodziak J, Methratta L, Stockhausen W, Col L, Griswold C (2008) The Northeast U.S. continental shelf Energy Modeling and Analysis exercise (EMAX): Ecological network model development and basic ecosystem metrics. Journal of Marine Systems 74:453-474
4 Link JS, EA Fulton, RJ Gamble (2010) The northeast US application of ATLANTIS: A full system model exploring marine ecosystem dynamics in a living marine resource management context. Progress In Oceanography 87: 214-234
5 Levin SA & J Lubchenco. (2008) Resilience, Robustness, and Marine Ecosystem-based Management. BioScience 2008 58 (1), 27-32
6 Sorte CJB, SL Williams, JT Carlton (2010). Marine range shifts and species introductions: comparative spread rates and community impacts. Global Ecology and Biogeography
19(3): 303–316.
7 Nye JA, Link JS, Hare JA, Overholtz WJ (2009) Changing spatial distribution of fish stocks in relation to climate and population size on the Northeast United States continental shelf. Marine Ecology Progress Series 393:111-129
8 Bakun A.(1996) Patterns in the ocean: Ocean processes and marine population dynamics. California Seagrant System
9 Agostini VN & Bakun A. (2002) ‘Ocean triads’ in the Mediterranean Sea: physical mechanisms potentially structuring reproductive habitat suitability (with example application to European anchovy, Engraulis encrasicolus). Fisheries Oceanography 11(2): 129-142
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