CRD 04-01 Session II

Current fisheries research and future ecosystems science in the Northeast Center: collected abstracts of the Northeast Fisheries Science Center’s Eighth Science Symposium, Atlantic City, New Jersey, February 3-5, 2004. Northeast Fish. Sci. Cent. Ref. Doc. 04-01 SESSION II
Species-habitat characterization for the Georges Bank ecosystem	Session II, Abstract II-1 ORAL PRESENTATION
Sukwoo Chang¹, Peter Berrien¹, Donna Johnson¹, Joseph Kane², Jay O’Reilly² and Maureen Taylor³¹NOAA/NMFS/NEFSC, 74 Magruder Road, Highlands, NJ 07732 ²NOAA/NMFS/NEFSC, 28 Tarzwell Drive, Narragansett, RI 02882-1152 ³NOAA/NMFS/NEFSC, 166 Water Street, Woods Hole, MA 02543-1026
Field studies of the MARMAP (MArine Resources Monitoring Assessment and Prediction) program (1977-1987) provide observations on the changes of hydrographic and nutrient measurements, as well as zooplankton, ichthyoplankton, fish distribution and abundance in the shelf ecosystem. These results can be used in determining the impacts of temporal and spatial variability of biotic and abiotic components and in establishment of their associations as well. Association analysis of MARMAP data from Georges Bank (GB) utilized a multiple-tier, species-habitat characterization procedure. The first two tiers are time (i.e., month, season or Julian date) and space (i.e., sub-regions or distinct water masses) attributes. Bottom temperature ranges can be used as the third tier attribute. Species associations, trophic associations and habitat associations have been estimated for 80 habitat units (4 seasons x 4 regions x 5 temperature ranges) for three tiers. Extended analysis of associations including 8 subdivisions of Julian date over a year and 9 water masses has been performed. Using 5 bottom temperature ranges as a third tier, then 360 (= 8 X 9 X 5) habitat units can be created, and including 3 additional depth zones used as a fourth tier, results in 1080 habitat units created. The more attributes that are added as tiers in analysis, the more refined species-habitat associations can be estimated in the smaller habitat units, if data are available for those habitat units. These species-habitat associations provide important understandings of fish habitats as well as their populations and community structure of the GB ecosystem. Associations may further explain why some fish species are not only more abundant and flourish longer than other species, but also what are the contributing factors for essential fish habitat (EFH) of the species in the GB ecosystem.
Density-dependent habitat use in the Gulf of Maine and Georges Bank or what do Fretwell and Lucas know about fish anyway?	Session II, Abstract II-2 ORAL PRESENTATION
Jose J. Pereira¹, Eric Schultz²and Peter Auster³¹NOAA/NMFS/NEFSC, 212 Rogers Ave., Milford, CT 06460 ²University of Connecticut, 75 N. Eagleville Road, U-3043, Storrs, CT 06269-3043 ³National Undersea Research Center, University of Connecticut at Avery Point, 1080 Shennecossett Road, Groton, Connecticut 06340-6048
The addition of essential fish habitat (EFH) provisions to fisheries management plans by the Sustainable Fisheries Act of 1996 and the concern over the effect of fishing gear on the sea bottom have prompted much interest in more accurate definitions of fish habitat use. The effort to implement this legislation has identified four different levels of information that could be used for EFH designations: Presence-absence data Habitat-specific population densities Growth, reproduction or survival rates within habitats Habitat-specific production rates Many EFH designations rely heavily on the first two levels of information and provide little insight into which portions of the habitat are critical for the population. One way to improve the sophistication of these descriptions, when long-term records are available, is to take into account density-dependent habitat use as described by Fretwell and Lucas (1970)[1]. The Fretwell and Lucas model predicts that at low population densities, organisms should occupy only optimal habitats. Organisms colonize less desirable habitats only when higher population levels result in density-dependent degradation of optimal habitat quality. Trawl survey data collected by the NEFSC represent a long time series collected at many different population densities and provide a unique opportunity to look for evidence of density-dependent habitat use and perhaps to identify optimal fish habitats. I have examined a subset of this dataset, the abundance and distribution of cod (Gadus morhua) from 1970-1994 in the Gulf of Maine and on Georges Bank, for evidence of density-dependent habitat use by statistical and geostatistical methods. First, I examined the degree of aggregation at different population densities by modeling the data as a negative binomial distribution and examining the value of the k-exponent (an inverse measure of aggregation) at different overall population densities. I also examined the coefficient of variation of the trawl data and how it varied with density. Semivariograms were used to examine spatial relationships in the data. Preliminary results do not support the theory of density-dependent habitat use, at least at large spatial scales. [1] Fretwell, S. D., and H. L. Lucas Jr. 1970. On territorial behavior and other factors influencing habitat distribution in birds I. Theoretical development. Acta Biotheoretica 19:16-36.
Three-dimensional visualization of fisheries’ acoustics data and models	Session II, Abstract II-3 ORAL PRESENTATION
David F. Chevrier and J. Michael Jech NOAA/NMFS/NEFSC, 166 Water Street, Woods Hole, MA 02543-1026
Fisheries’ acoustics methods are an efficient and effective approach for providing fisheries-independent estimates of densities and abundances of commercially important fish stocks. Acoustical data collected during fisheries surveys provide continuous coverage of the entire water column along the cruise track. Concurrent biological sampling from net hauls and underwater video systems allow verification of the sources of acoustical echoes. Typically the acoustical data are displayed as two-dimensional 'echo grams' - vertical dimension through the water column, and time along the horizontal axis. Traditional echograms are not suitable for viewing the data in a geographical context. We have developed three-dimensional visualizations of multi-frequency acoustical survey data to view the data in geographical space from small to large spatial scales. Acoustical data are commonly used to provide relative indices of species-specific abundance and biomass. In order to scale the relative indices to absolute estimates, we must incorporate a measure of the echo amplitude from an individual fish. Fish are complicated acoustical scatterers by nature of their complex anatomy and behavior. We have developed three-dimensional visualizations of the fish body and swimbladder from x-ray and Computerized Tomography (CT) images. These images are used in theoretical models to improve prediction of acoustical scattering over a wide range of frequencies and fish orientations. We will present three-dimensional visualizations of acoustical survey data and internal anatomy of selected fish species, and will discuss the utility and implications of 3D visualizations in fisheries management.
Plankton monitoring utilizing a MOCNESS mounted Video Plankton Recorder	Session II, Abstract II-4 ORAL PRESENTATION
Elisabeth Broughton NOAA/NMFS/NEFSC, 166 Water Street, Woods Hole, MA 02543-1026
Plankton identification and enumeration are a highly specialized, time-consuming part of the Northeast Fisheries Science Center's monitoring and research programs. In an effort to speed processing and provide the vertically stratified plankton data utilized by newly developed ecosystem monitoring models, a self-contained, analog Video Plankton Recorder (VPR) was integrated with the 1m MOCNESS. VPR data collected in May 1997 along a mooring line in the Great South Channel was compared to the net samples taken simultaneously by the MOCNESS to test the accuracy relative to conventional net samplers. The VPR data was then analyzed to show fine scale (1m) vertical variance and any significant changes between casts within a single haul. A detailed picture of the zooplankton assemblage along the mooring line was created. Currently we are working to automate the processing and identification systems. The computer will automatically extract every region of interest (ROI) as a Tiff file and tag it with a time code. ROIs can then be imported into a MATLAB based processing program that allows the user to identify the plankton and take multiple measurements. Utilizing the time stamp this data is then automatically integrated with the physical oceanographic data from the MOCNESS sensors. In the future, a slight change in mounting brackets and the self-contained VPR can be deployed on other oceanographic sampling gear such as CTDs, bongos, or a towed V-fin. The proposed computer software can append physical oceanographic sensor data from a variety of sources. The system will be converted to digital to reduce the size of the gear and further speed processing. With the addition of software developed by WHOI, the identification stage can also be completely automated. This would provide for a small scale vertically stratified, plankton profile to be completed within 2 hours or less of the sample being downloaded to the ship’s computer.
A comparison of organic nutrient levels in near-shore and offshore environments	Session II, Abstract II-5 ORAL PRESENTATION
John E. McCarthy, Vincent G. Guida, and Andrew F. J. Draxler NOAA/NMFS/NEFSC, 74 Magruder Road, Highlands, NJ 07732
Total Organic Carbon (TOC) and Total Nitrogen (N) levels were determined in marine sediments in support of a fishing gear effects study in Closed Area II of Georges Bank and a lobster mortality study in Long Island Sound. Trends in nutrient levels with sediment types and depths were examined. TOC levels were significantly higher in the finer Long Island Sound near-shore sediments (0.08% - 3.37%, average 1.18%) than in the sandier Georges Bank offshore sediments (0.005% - 0.218% average 0.055%). While there is a general trend for finer sediments to have higher TOC and N levels, the difference in the two areas is so large that the impact of human activity in the Long island sound area most likely outweighs any differences due to grain size variations. TOC/N ratios were determined when possible. The similarity in TOC/N ratios in the two areas suggests that the nature of the nutrient materials is similar despite the differences in overall levels.
*The outer shelf of the mid-Atlantic:Terra incognita* at our doorstep**	Session II, Abstract II-6 ORAL PRESENTATION
Vincent G. Guida¹, Page C. Valentine², Frank Almeida³, Michael Fahay¹, Joseph J.Vitaliano¹, Maureen H. Taylor³, Martha S. Nizinski⁴, and Lauren Pandolfo⁵¹NOAA/NMFS/NEFSC, 74 Magruder Road, Highlands, NJ 0773 ²USGS, Woods Hole Field Office, 384 Woods Hole Rd., Woods Hole, MA 02543 ³NOAA/NMFS/NEFSC, 166 Water Street, Woods Hole, MA 02543-1026 ⁴NOAA/NMFS, National Systematics Laboratory, National Museum of Natural History, Washington, D.C. 20560-0153 ⁵Roger Williams University, Dept. of Biology and Marine Biology, Bristol, RI 02809
The outer continental shelf and upper slope around Hudson Canyon is heavily fished, but little explored. Combinations of hydrology and sedimentology create a haven for resident deepwater and overwintering inshore-offshore migrant species. Details of habitat nature, distribution, and use have been scarce until recently, when NEFSC Benthic Habitat cruises began exploration. Issues addressed include: Defining the extent and density of habitat islands associated with tilefish burrows; Realizing the prevalence of previously underestimated and/or overlooked benthic megafauna and demersal forage species; Discovering previously unexplored fish habitats, including boulder piles, Bolocera gardens, and canyon margins; Revealing northerly range extensions for several southern species; Discovering a rich and unique benthic infauna; Finding the first known colonial deepwater corals on the US Atlantic shelf; Investigating damage from mobile fishing gear; Revealing deepwater temporal activity patterns such as crepuscular swarming and feeding; Revealing large-scale spatial patterns in organism distribution; and Utilizing new technologies like video, still photo and sonar analysis for defining meso-scale patterns. The extent to which new discoveries thus far have been made “by accident,” i.e., not by way of a well-planned, focused, hypothesis-driven sampling scheme, suggest that there is still much to be revealed by further field exploration. Near-term goals for continued work include more rigorous sampling to determine the extent and character of coral areas and other rich habitats, developing better field and lab methods for the characterization of resource-habitat relationships, and investigating sediment biogeochemistry as an indicator of system condition. Long-term goals include habitat characterization using multi-beam mapping.
*Preliminary Observations on the Diversity of the Invertebrate Fauna Associated with Lophelia* Banks off North Carolina**	Session II, Abstract II-7 ORAL PRESENTATION
Martha S. Nizinski¹, Steve W. Ross², and Kenneth J. Sulak³¹NOAA/NMFS, National Systematics Laboratory, Smithsonian Institution, PO Box 37012, NHB, WC-57, MRC-153, Washington, DC 20013 ²Center for Marine Science, University of North Carolina-Wilmington, 5600 Marvin Moss Lane, Wilmington, NC 28409 ³U.S. Geological Survey, Biological Resources, 7920 NW 71st St., Gainesville, FL 32653
Extensive reefs of Lophelia pertusa occur on the middle continental slope (350-700 m) of the Blake Plateau off the southeastern United States. Submersible observations revealed that these deep reefs support a diverse fish and invertebrate community. Preliminary analysis of data from collections, still photos, and videotapes to assess the invertebrate fauna associated with these deep reefs indicates that crustaceans and echinoderms are the numerically dominant components of the invertebrate fauna. Additionally, for some invertebrate taxa, species diversity is relatively low, however, numerical abundance of a particular species can be very high. For example, four species of galatheid crabs have been identified to date. One of these species, Eumunida picta, is a conspicuous and dominant member of the Lophelia associated fauna, while other galatheids are represented by few specimens. Community structure of these reefs remains poorly studied. However, several habitats (e.g., living coral, dead coral, coral rubble, sand) within the reef system have been identified. Aspects of the reef associated invertebrate assemblage observed at the North Carolina sites with regard to habitat utilization will be discussed and compared with that reported for associated invertebrate fauna observed at other Lophelia reefs in the Atlantic. Whether species within this community are unique to reef habitats, or are species of more widespread distribution that utilize reefs opportunistically, is still largely unknown. We will attempt to assess whether Lophelia reefs function as a primary habitat for these invertebrates, or if these reefs function only as alternative habitat that is occupied opportunistically by these species.