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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 V
Indirect age estimation of butterfish (Peprilus triacanthus) based on otolith weights:  preliminary results	Session V, Abstract V-1 ORAL PRESENTATION
Sandra J. Sutherland, Nancy Munroe, Elizabeth O’Neill, and John Burnett NOAA/NMFS/NEFSC, 166 Water Street, Woods Hole, MA  02543-1026
In this study, we investigated the feasibility of using otolith weights to predict age in butterfish (Peprilus triacanthus). Our goal was to develop a simple and efficient method capable of providing acceptable age estimates for stock assessment modelling, yet which could be done by less highly-trained technicians than traditional age determinations. Butterfish are a short-lived species, attaining a maximum age of six years and a length of about 25 cm. The Northeast Fisheries Science Center has aged butterfish using whole otoliths for over 25 years. However, due to increased demand for age data in recent years, this lab is currently seeking methods to increase our efficiency in generating age data. Using otolith weights as a proxy for aging has been successful in various other fish species, and butterfish appear to be a good candidate for this approach. Preliminary results (n = 75) indicate that there was no difference between the weights of left and right otoliths within a fish. Otolith weight appears to be independent of fish length, and slightly decalcified otoliths did not affect the otolith weight significantly. Therefore, most underlying assumptions necessary to using this method have been met.  A preliminary linear regression explained 70% of the variability. Further work will include measuring additional otoliths and accounting for any a priori growth differences between inshore and offshore groups of fish, and effects of fish length, sex, and sampling year. The predicted age distributions will then be compared to those obtained from traditional age determinations. A cost-benefit analysis will also evaluate the trade-off between increased efficiency and age determination accuracy.
A model to estimate growth rate in young-of-the-year tautog, Tautoga onitis, based on RNA/DNA ratio and seawater temperature	Session V, Abstract V-2 ORAL PRESENTATION
Renee Mercaldo-Allen1, Catherine Kuropat1, Elaine Caldarone2 and Ronald Goldberg1 1NOAA/NMFS/NEFSC, 212 Rogers Ave., Milford, CT  06460-6490 2NOAA/NMFS/NEFSC, 28 Tarzwell Drive, Narragansett, RI  02882-1152
This study defines the relationship among RNA/DNA ratios, seawater temperature, and weight-based instantaneous growth coefficient (G) in young-of-the-year (YOY) tautog, Tautoga onitis. Correlation results showed a significant positive relationship between RNA/DNA and weight-based growth (r = 0.68), and a significant negative relationship between RNA/DNA and temperature (r = -0.51), and RNA and temperature (r = -0.57). Multiple linear regression analysis indicates that RNA/DNA ratio and seawater temperature explains 60% of the variability in growth of young tautog. These results were used to develop the following equation: G= 0.01391 (RNA/DNA) + 0.0005(T) -0.03155. This RNA/DNA - temperature model can be used to evaluate recent growth in YOY tautog under field conditions and may prove useful in assessing growth of fish in aquacultural systems.
Growth of juvenile black sea bass, Centropristis striata, in a recirculating seawater system	Session V, Abstract V-3 ORAL PRESENTATION
David A. Nelson1, Dean M. Perry1, Robin Katersky1, Stephen Metzler2 and Dylan Redman2 1NOAA/NMFS/NEFSC, 212 Rogers Ave., Milford, CT  06460-6490 2End to End Technical Services Inc., Portsmouth, VA 23704
The black sea bass, Centropristis striata, is currently being investigated as a potential aquaculture species.  Although black sea bass show great potential for aquaculture, studies have not yet demonstrated the time required to produce a market-size fish.  Our goal is to grow black sea bass from larvae to market size adults (454-680 grams) in 24 months or less.  Adult black sea bass broodstock collected from the wild were naturally spawned in the laboratory by photothermal manipulation.  Embryos were then hatched in cone-bottom tanks that are part of a closed, recirculating seawater system.  Fish remained in this system for 3-4 months and were culled by size before being transferred to three grow–out tanks that are also part of a recirculating seawater system.  Fish are measured and weighed on the day of transfer and then every two weeks thereafter.  Fish produced in 2001 were culled into two size groups that had mean lengths of 245.6 and 196.5 mm, and grew to mean weights of 284.2 and 203.7 g. after 24 months.  Fish spawned in 2002 were culled into three size groups.  These fish had mean lengths of 160.7, 190.7 and 225.1 mm and grew to mean weights of 73.0, 121.0 and 206.8 g after 19 months.  To further understand factors that control growth, future research efforts should investigate temperature, lighting, reproductive physiology, and nutrition.
How different light regimes and intensities affect growth rates and nutrient uptake in Tetraselmis chui (PLY429)	Session V, Abstract V-4 ORAL PRESENTATION
Shannon L. Meseck and Jennifer Alix NOAA/NMFS/NEFSC, 212 Rogers Ave., Milford, CT  06460-6490
Mass culturing phytoplankton in large volume tanks (i.e., 18,000-L) is a practical way to produce live feeds for aquaculture.  To reduce culturing costs, greenhouses can be used to minimize the amount of artificial light needed for algal growth; however, with natural sunlight there is much more variation in the light intensity and the day length than what would be found in a controlled laboratory environment.  Light intensity, day length, and nutrient concentrations are important in regulating the growth of phytoplankton.  This study investigated how different light intensities and day lengths affect the growth and nutrient uptake of Tetraselmis chui (PLY 429) an algal strain used widely as an aquaculture feed. Tetraselmis chui cultures were grown aseptically in E/4 media (similar macro-nutrient concentrations as f/2) at a temperature of 18oC.  Four different light-dark cycles and three different irradiances were used, in a factorial experiment, to determine the relative importance of total light energy input and day length in controlling nutrient uptake and growth.  Longer light-dark cycles and higher light intensities resulted in higher biomass production and complete utilization of nitrate and phosphate in less time, as compared with shorter days and lower intensities.  Cultures exposed to 8 hours of light per day had minimal growth and nutrient uptake at all intensities.  This finding that day length is important in determining growth and nutrient uptake in PLY429 suggests that, in New England during the winter months, artificial light will need to be added to algal cultures in a greenhouse.
The effects of shell hash on the survival and transport of juvenile Spisula solidissima	Session V, Abstract V-5 ORAL PRESENTATION
Shannon Newby Institute of Marine and Coastal Sciences, CMER program, Rutgers the State University
Shell hash is one of the structural elements in sandy sediments of New Jersey’s continental shelf.  Structural elements frequently affect predation rates and transport distances of juvenile bivalves by altering the near bed flow regime.  Atlantic surfclams, Spisula solidissima, settle in areas both with and without shell hash in high densities, which are subsequently reduced.  Predation on the newly settled juveniles is considered to be the major cause of loss, however, transport of the juveniles from their initial settlement site could also be a factor.  Laboratory flume experiments conducted at Rutgers University examined how predation on, and transport of juvenile S. solidissima were impacted by the presence or absence of shell hash.  The near bed flow was compared between a flat bed and a shell hash bed, to determine how the physical environment altered when structure was present.  Other experiments examined the predation success of the omnivorous hermit crabs, Pagurus longicarpus, on juvenile (0.5 – 2 mm) S. solidissima and the transport distances of larger (3.5 – 7.5 mm), juveniles in flat and shell hash beds.  These experiments indicated that the presence of shell hash reduced near bed flow velocity, and increased near bed turbulence.  Ripples formed at high (30 cm s–1) free stream velocities when shell hash was present.  Predation rates on 0.5 – 2 mm S. solidissima by P. longicarpus were unaffected by the presence of shell hash.  Larger, 3.5 – 7.5 mm, S. solidissima were transported shorter distances in shell hash beds compared to those in flat beds.  While shell hash may not alter predation rates on S. solidissima, it does decrease their transport to potentially unsuitable locations.  It is expected that larger numbers of S. solidissima would be found in sandy environments containing shell hash and/or ripples in the field compared to areas with little or no habitat structure.
The Mid-Atlantic Fishing Communities Project	Session V, Abstract V-6 ORAL PRESENTATION
Bonnie J. McCay, Kevin St. Martin, Bryan Oles, Brent Stoffle, Johnelle Lamarque, Katie Broskey, Satsuki Takahashi, and Teresa Johnson Dept. of Human Ecology, Cook College, Rutgers the State University, New Brunswick, New Jersey
National Standard 8 of the Magnuson-Stevens Fishery Management Act creates a new requirement in fisheries management planning to take into account the needs of fishing communities, within the framework of conservation objectives.  It poses a challenge in determining which communities are ‘fishing communities’ under the act and in developing adequate baseline descriptions of the communities that can be used in federal fisheries management.  There are other legal requirements for similar work, which we agreed to do through a CMER grant.  We focused on the Mid-Atlantic region, from Montauk, Long Island, to Cape Hatteras, North Carolina.  I will present an overview of the fishing communities of the region and comment upon the changes that are taking place that influence their exposure and vulnerability to changes in the regulatory environment.  One of the defining characteristics of fishing communities of the Mid-Atlantic region is that they are typically embedded in communities primarily oriented in other ways, for example tourism or urban-suburban residential development.  Many are undergoing ‘gentrification’ processes, which result in changing values and political relations that can pose difficulties for water- and waterfront-dependent enterprises such as commercial and recreational fishing.  We argue that this does not diminish their importance as fishing communities under the Magnuson-Stevens Act but rather highlights their increased vulnerability (or decreased resilience) to the short-term effects of environmental and regulatory changes.