3b. Background

1969/12/31 - 20:00

3b1. Species, Community, and Habitat Information Requirements for Ecosystem Approaches to Management

Ecosystem approaches to management (EAM) of shelf seas will involve meeting multiple goals based on objectives set within various management and legal regimes, and will require information on the status and trends of ecosystem elements at nested spatial and temporal scales.  Elements will include attributes of species, communities, habitats, and landscapes as well as oceanographic factors such as primary and secondary production, and water column structure (e.g., frontal zones). Existing laws illustrate the disparity in goals. For example, fisheries goals seek to exploit wild populations of a limited number of (primarily) dominant species in a sustainable way, while natural heritage marine protected areas (like most National Marine Sanctuaries [NMS]) are concerned with conservation of rare species and the effects of allowing various types of human uses. Existing legal frameworks already include many elements that will be integrated into EAM. The Sustainable Fisheries Act of 1996, and recent reauthorization of the Magnuson-Stevens Fishery Conservation and Management Act (MSFCMA), requires designation of Essential Fish Habitat (EFH) whereby under the authority of the Secretary of Commerce, the National Marine Fisheries Service and the eight regional Fishery Management Councils shall (1) Describe and identify EFH for each managed species; (2) Minimize to the extent practical the adverse effects of fishing on EFH; and (3) Identify other actions to encourage the conservation and enhancement of EFH. Conversely, the National Marine Sanctuaries Act (NMSA) requires protection of resources (i.e., biodiversity) while allowing multiple use. While complete knowledge of our offshore resources including biological, chemical, geological, and physical interactions would allow the most enlightened identification and management of EFH and NMS, the magnitude of such an undertaking is beyond our reach. Thus, we must of necessity select a small number of priority areas for study, and correctly understand and select the useful variables to be measured over specific time scales, in order to produce results applicable to the greater continental shelf area.

EAM requires knowledge of the overall productivity and sustainable yield for a geographical area, which is dependant on inter-relationships between human activity, biological processes, chemical dynamics, geological formations, and physical oceanography in the water column. Fundamental to EAM is understanding how these inter-relationships change over time in response to both anthropogenic and natural factors. The development of an ecosystem approach to fisheries management is a subset of the EAM strategy and entails defining Fishery Ecosystem Plans (FEP) for particular regions. The NMFS Ecosystem Principles Advisory Panel (Fogarty et al. 2006) suggests the following steps to defining a FEP: 1. Delineate the geographical extent of the ecosystem by characterizing the biological, chemical and physical dynamics; 2. Develop a conceptual food web for the ecosystem; 3. Describe habitat requirements for life history stages for all significant components of the conceptual food web; 4. Calculate total mortality, both natural and through fishing in relation to standing stock, production, optimum yield, and trophic structure, and estimate uncertainty; 5. Develop indices of ecosystem health as targets for management; and 6. Develop long term monitoring of key variables and show how they should be used in management. Here we propose to develop capabilities for integrated survey methods using a suite of advanced tools to act as a mobile observatory for reconnaissance to selected, sentinel areas, and begin to craft the tools necessary to integrate the collected datasets into information readily understood and useable by both fishery and ecological scientists, and fishery managers towards ecosystem based management practices.

3b2. Oceanography and benthic community structure

A variety of oceanographic features directly impact benthic communities. The degree of stratification controls vertical mixing and delivery of nutrients and particularly oxygen to the benthos. Shallow regions of Georges Bank remain well-mixed even during summer while regions of the Mid-Atlantic Bight become strongly stratified and, at times, experience oxygen depletion and anoxic conditions. Sharp discontinuities between water mass characteristics form frontal boundaries, which provide a mechanism for high mixing rates, concentration of plankton and fish, and enhanced productivity. The 60m isobath around Georges Bank and the Shelf/Slope break off of New Jersey are two examples of bathymetric features where water column productivity is greatly enhanced due to thermal fronts. The benthic community below fronts benefit by and indeed are structured by this enhanced water column production by delivery of larvae, phytoplankton and other forms of carbon, nitrogen, and energy and through enhanced mixing. For example, the most productive areas for many of the regions’ fisheries are along frontal boundaries in and around Great South Channel, the Northern Edge of Georges Bank, and along the shelf break south of Hudson Canyon (Fig. 2. Appendix). Moreover, water column processes are key to recruitment and survival of many benthic and demersal fin fish, shellfish, and other organisms with meroplanktonic larvae. Together with benthic habitat, delivery of food and energy from the water column to the benthos to a large extent is what controls carrying capacity of a region.

3b3. The importance of time scales

To address EAM, and more specifically multi-species FEPs, we need to understand the critical of scales for processes driving ecosystem structure and dynamics extending from climate on scales of 1000km and decades to predator-prey interactions on scales of mm and minutes. One index of climate change is the North Atlantic Oscillation (NAO), the difference in sea level between the Azores and Iceland in winter. A high NAO generally means increased storm activity across the Atlantic, low water temperatures off Labrador and relative high temperatures off the US coastline. The reverse is true during low NAO. During the past several decades NAO has been generally positive, but we are entering a negative NAO at this time. How this affects the oceanography and hence productivity of the region in an area is debatable, but it’s clear that penetration of cool, fresh, nutrient poor, Labrador-Subarctic Slope Water to the south displacing Atlantic Temperate Slope Water off Georges Bank could have a direct impact on benthic fauna and flora, persisting for decades or longer. For example, as noted above, oceanographic features such as frontal boundaries are critical components of ecosystem productivity. If these features are displaced or modified in some way due to climate-based processes, EAM strategies need to incorporate measures of how productivity changes on these relatively long time scales. Moreover, persistent changes in temperature, the degree of thermal and density stratification, mixing, and nutrient injection have a direct impact on faunal boundaries between tropical, temperate and boreal conditions. The general warming of the ocean in the Georges Bank region correlates with a northern migration of many sub-tropical fish species (Mountain and Murawski 1992).

Cyclical processes occurring at shorter time scales such as inter annual, seasonal, lunar, diel, and tidal provide a specific structuring force on benthic communities as a function of frequency. Very short, episodic impacts such as storms are critical ecosystem drivers by providing mixing, resuspension, nutrient injection, and fresh water run off. A comprehensive description of an ecosystem and how it changes over time must take into account a multiplicity of driving forces and their wide ranging time and space scales.

3b4. Human impact on benthic structure and diversity

Humans impact benthic communities in a variety of ways. Our interest in restricting  bottom trawling in certain areas by closing areas to fishing in the northeast is an attempt to limit effects to essential fish habitat. Heavily trawled regions of the bottom typically have low species diversity and are thought to provide poor habitat for fin fish such as cod and haddock, which require fairly complex habitat. Anthropogenic sources of pollution such as mercury, viruses, and excess nitrogen can destabilize benthic communities and decrease diversity by altering predator-prey interactions and forcing enhanced production of unwanted plant species. Tracking and incorporation of human activity and its impact on benthic community structure into socio-economic fisheries models, as proposed here, is necessary to predict ecosystem change.

3b5. Current Approaches to Obtaining Data for EAM

The diversity of measurements required for EAM necessitates a variety of approaches for data acquisition. Historically, the NMFS has relied on ship based monitoring of the plankton, fish and benthic communities using nets and bottom trawls, but more recently tools include hydroacoustics for herring surveys and benthic habitat studies, satellites for observing large scale patterns of hydrography and primary production, GPS transponders on fishing vessels to observe fishing pressure, optical imaging systems to quantify plankton abundance, moored buoys with meteorological and hydrographic sensors, aerial surveys and acoustic tags for large marine mammals and turtles.

The IOOS program promises to fundamentally revolutionize the way we collect data from the ocean and how we think about multi-scale processes. By adding the capability to provide sustained, high frequency measurements of key ecosystem variables from a variety of geographic locations and integrate disparate data sets to create a 4-Dimensional view of the ocean and its properties, IOOS, including NERACOOS, NEBO, and MACORA, will provide the context necessary to address issues of direct societal need such as improved climate predictions, improved safety at sea, mitigation of the effects of natural hazards, improved homeland security, reduced public health risks, protection and restoration of coastal ecosystems, and enable sustained use of ocean resources through intelligent management practices.

3b6. Variables needed to be measured and indices developed for EAM

There are several key concepts required for EAM; for example, sustainable yield, species-specific total allowable catch, recovery time, bentho-pelagic coupling (energy flow), and habitat functional value. Variables needed to be measured include species abundance, distribution, substrate composition, water column properties (temperature, salinity, nutrients, phytoplankton, zooplankton). Indices needed to be developed include: patchiness indices, inter-species and inter-substrate type relationship indices, species diversity in relation to substrate at multiple spatial scales, water column processes, assess community composition including dominant and rare species across habitat types and over time, assess habitat associations of key fish taxa based on variations in size and density, and habitat classifications that include attributes of grain size and biogenic components. Most importantly, collaboration is required for the purpose of developing data products for use by NMFS and the New England Fishery Management Council for fisheries management (including Essential Fish Habitat) and Stellwagen Bank National Marine Sanctuary and the Sanctuary Advisory Council for management of a multiple use natural heritage marine protected area.

3b7. Status of the fisheries with regard to habitat and habitat issues

Rebuilding spawning biomass and stock size have been the central issues of recent fisheries management plans. Simultaneously with major changes in the laws regarding fisheries, mobile bottom tending fishing gear used extensively in the commercial groundfish and scallop fisheries in US waters have been the subject of increasing scrutiny (Auster and Langton 1998, Pederson and Dorsey 1998). Repeated trawling is indicated as a major component in reduction of structure of the ecosystems necessary for the production of  fishery resources (National Academy of Science 2000). Given the lack of long term documentation of bottom habitats, the supposition is that fishing gear in use for the past 80 years may have potentially far-reaching consequences (Lindholm et al. 2001). Our existing knowledge of habitat dynamics and the dynamics of seafloor communities (and patterns of diversity) in general, and species of economic importance in particular, is limited. Currently, we do not have spatially comprehensive baseline or time series data over sufficiently large areas to understand habitat and community state and dynamics, at scales relevant to management, with a high degree of certainty  (but see Collie et al. 2005, Knight 2005, Tamsett and Auster 2006 for specific sites off the northeast U.S.). We have only patchy information on substrates, less for associated fauna, and we are just beginning to understand the scope of variation in recovery dynamics from perturbations at various space and time scales.

The core of the EFH mandate is the correlation of substrate type and associated fauna with habitat or ecosystem value, e.g. the function of the local area in providing increased survival to (commercial) fishes, in order to develop a metric for the level of ecosystem functioning for sympatric taxa. Five recent efforts have proceeded beyond substrate description and classification (Theroux and Wigley 1998, Todd et al 2000, Auster et al 2001, NMFS 2001, Valentine et al. 2005) moving us closer to understanding species associations and thus the functional aspects of marine habitats.

In this proposal, we address these needs by combining the efforts of fishermen with existing knowledge of what and who is where, with the expertise of scientists and engineers who are developing the most advanced imaging technologies available today. The issues addressed here are: 1. Multi-scale processes affecting habitat and species composition; 2. Recovery rates and dynamics of impacted habitats; and 3. Scale dependent distribution of micro habitats within regional areas. Our dearth of knowledge underscores the need to begin high resolution, wide area repeated surveys of bottom habitat that will document the current status and trajectories for system change so that we can develop future management actions and predict their effects on essential fish habitat and marine protected areas.

3b8. Avalable sources of habitat information

Central to our dilemma of both conservation and exploitation of marine resources is our lack of specific knowledge about what lives where, when, and why. The NMFS trawl survey time-series is the most comprehensive spatial information currently available, sparsely covering a wide area over three seasons. However, this survey was not designed to delineate or classify seafloor habitat at the resolution needed to link to community dynamics, patterns of diversity and species productivity needed to strategically manage human activities and impacts. With the large mesh gear in use, sampling efficiency is poor, and tow lengths are often so long that samples from diverse habitats are combined in a single haul. To address these issues we have developed the HabCam (Gallager et al. 2005; Howland et al, 2006), a towed habitat mapping camera system designed to collect very high-resolution color images of the seafloor and accurately locate each image captured along its path, providing explicit maps and accurate statistical descriptions of habitat and distribution of key taxonomic groups.

Unlike the seafloor, the land surface of the Earth can be analyzed on a daily basis via remote sensing using a variety of instruments that can measure critical habitat attributes over large areas with high resolution: e.g. elevation, wind speed, precipitation, temperature, optical imagery and reflected radiation at numerous wavelengths. However, the relative opaqueness of the ocean to electromagnetic wavelengths prevents a similar approach to the classification of benthic characteristics at synoptic scales. Several technologies have demonstrated utility for seafloor characterization at various scales: Light Detection and Ranging (LIDAR), Laser Line Scan (LLS), and acoustic technologies such as sidescan and multibeam sonars. We have chosen to integrate multibeam into this project in order to generate maximum coverage and information during reconnaissance transects.
Recently Fonseca and Mayer (in press) have introduced a physics-based approach to seafloor characterization using multibeam sonar data. This approach takes advantage of the wide swath coverage of multibeam echosounders and uses the angular dependence of the acoustic response of the return in concert with a physics based model to extract quantitative information about seafloor properties. The parameters extracted from this model (at a scale that is on the order of the swath-width) are acoustic impedance, rms-roughness and grain size, all factors that are relevant to seafloor habitat.  This project will quantify organism distribution on scales of mm to 100’s km, substrate type, and oceanographic features within the benthic boundary layer and in the water column, in collaboration with NERACOOS.

3b9. Existing IOOS-related organizational structure

The NOAA sponsored Coastal Observation Technology System (COTS) was developed to coordinate a series of Regional Coastal Ocean Observing Systems (RCOOSs) as part of the IOOS development plan (http://www.ocean.us/ioosplan.jsp).
The Northeast region has four COTS programs underway:  the Long Island Sound Integrated Coastal Observing System (LISICOS, http://www.lisicos.uconn.edu), the NOAA-UNH Joint Center for Ocean Observing Technology (JCOOT, http://www.jcoot.unh.edu), the Coastal Ocean Observing Center at UNH (COOA, http://www.cooa.unh.edu), and the Gulf of Maine Ocean Observing System (GoMOOS, http://www.gomoos.org/). In addition, WHOI built and operates the Martha’s Vineyard Coastal Observatory (e.g., http://4dgeo.whoi.edu/vpr) which provides a continuous data stream of water column properties south of Martha’s Vineyard.

The Northeastern Regional Coastal Ocean Observing System (NEARCOOS) is being developed to integrate the four COTS projects and the MVCO under one umbrella. However, none of the existing IOOS related projects have a program for sustained, repeated measurements of benthic community structure aimed at EFH and multi-species ecosystem based management. NEBO provides a benthic component for NERACOOS while water column observations provided by the northeast and mid Atlantic bight RCOOS will provide the oceanographic context to evaluate benthic habitat change. The current NEBO proposal, therefore, is highly complementary to all IOOS activities.