Session VIII: Posters
Bascuñán, James Manning, Maureen H. Taylor, and David
Water temperature has been collected on a near-daily basis for over a decade at nearly a dozen locations along the New England coast by various state, federal, and commercial institutions. These records have now been archived in a common ORACLE database and are available on the web. While NMFS labs have made a significant contribution to this set with time series from Woods Hole beginning in ’60's, Milford in the ’70's, and Narragansett in the ’80's, there are several other non-NMFS sites maintained, for example, by the Northeast Utilities power plants and the states of Massachusetts and Maine. The Division of Maine Resources in Boothbay Harbor now has nearly a century of data.
Now that these datasets are merged, how should we analyze the collective set? What does it say about long-term variability of our coastal waters? Can we track the transport of Canadian source water as it enters into and out of the Gulf of Maine and how important is the influx of remote sources relative to the local runoff and surface heating? These are questions that we can now begin to address and, while we have barely begun, there are some interesting preliminary results. The inter-annual variability of temperature anomalies (after removing seasonal cycles) is fairly coherent throughout the New England region. The sites mentioned above all recorded warm periods in ’84, ’91, and ’95 and cold periods in ’87/88, ’93, and ’96. There are some indications of warming in recent decades that are most evident in the early ’90's and during the winter months but this trend falls off in very recent years.
Sheila Stiles1, and Jessica Vinokur2
In the course of bay scallop aquaculture research conducted at the National Marine Fisheries Service Laboratory in Milford, CT, excess scallops were donated to Connecticut municipal shellfish commissions for free planting in area waters. The practice of free-planting or tossing seed scallops (10-40 mm) directly into the water has come under scrutiny because of the observable decreasing return in the number of adults (>60 mm) caught by recreational fisherman in the towns that have such policies. Field studies of bay scallops have suggested a variety of causes for population fluctuations including habitat loss, genetic inbreeding depression, and predation. It is generally known that crab predation can be a major factor in survival and growth of bay scallops for reseeding or stock enhancement efforts, especially in sites devoid of eel grass which can serve as a refuge for small scallops.
To evaluate crab predation on scallops and to test the influence of shell color on predator selection of prey, an experimental study was conducted with green crabs (Carcinus maenas) and blue crabs (Callinectes sapidus) in the laboratory. Six treatment aquaria with ambient flowing seawater were established with a single crab and 10 scallops. A seventh aquarium, with 10 scallops and no crab to check for non-predator related mortality, was used as a control.
Four separate trials were run with scallops in each of the following size classes: 10, 20, 30 and 40 mm shell height. Trials were duplicated with a second set of crabs and scallops. Observations were made at 1, 6, 20, and 48 hours for each study. Results indicated that larger-sized scallops had higher survival rates, indicating some degree of refuge from predation by green crabs.
The availability of scallops with different shell colors from our genetic lines provided an opportunity to conduct predator preference experiments. With scallops of similar size (~ 15 mm.) but with shell colors of white, yellow, stripe or brown there was a tendency for the lighter colored scallops to become the early meals. This tendency could have a prominent impact on restocking efforts and is being studied further.
The inclusion of the blue crabs to the experiments was due to a visual increase in the population by divers where we have found our broodstock. The blue crab showed to be as aggressive a predator as the green crabs and through its size, allowed very little refuge for any of the scallop prey.
In addition, damage to scallop shells was manifested in a characteristic appearance which could be used in identifying mortality by crab predation in the field.
Gary H. Wikfors and Mark
Experiences encountered in aquaculture research can provide unexpected insight into the principles of fisheries science. One such experience began with the introduction of a non-native species into an aquaculture environment – brine shrimp (Artemia) appeared mysteriously in a mass culture tank of microalgal strain UTEX2341, Nannochloropsis sp. The vector for this introduction may have involved human error, but we will attribute it to “The Brine Shrimp Faerie” to avoid controversy. We viewed the presence of a population of predators in our algal culture as an opportunity to explore the potential for polyculture, i.e., would it be possible to manage algal growth, algal removal by feeding brine shrimp, and brine shrimp population growth and harvest sustainably? Does this question sound vaguely familiar to anyone?
The experience proceeded as follows: Milford personnel using brine shrimp to feed larval fish harvested both algae and brine shrimp on an “as needed” basis, without benefit of statistical analysis of data. Harvesters recorded removal of algal culture and brine shrimp, while we recorded additions of new water and algal nutrients. Fishing mortality (f) and catch per unit effort (CPUE) were calculated with appropriate modifications for algal and brine shrimp population dynamics and tracked for 14 weeks. For the first 3 weeks, f remained below 0.2, and CPUE remained stable in the range of 0.35-0.75 Artemia per liter of algal culture. When removal of brine shrimp was accelerated (f>0.2), CPUE fell accordingly. One ten-day period with no brine shrimp harvest seems to have resulted in some recovery of the population, but several subsequent large harvests (f>0.4 in a short time span) resulted in a local extinction of the brine shrimp. In our case, the tank was drained, washed, re-filled, and re-inoculated with algae. If only it were this simple everywhere...
David D. Dow
In 1993 the U.S. Environmental Protection Agency (EPA) and the Waquoit Bay National Estuarine Research Reserve (WBNERR) established a partnership to develop a watershed-based ecological risk assessment case study for this coastal embayment on Cape Cod, MA. The Waquoit Bay watershed is 53 sq km in size, while the bay itself encompasses 4 sq km. A conceptual model of the watershed linked human activities to ecological stressors and their ecological impacts, identifying the endpoints for evaluating these effects. For example, residential development (activity) leads to increased nutrient enrichment (stressor) from septic systems and fertilizer usage which results in the loss of eelgrass beds/bay scallop populations (ecological effects) in the bay, with eelgrass habitat being the assessment endpoint and % eelgrass cover being the measurement endpoint.
Fuzzy set analysis was utilized to qualitatively evaluate the 8 water-based assessment endpoints (migratory fish, freshwater biota, wetland habitat, pond trophic status, toxic contamination, eelgrass habitat, estuarine invertebrates, and estuarine fish) in relation to the 6 dominant manmade stressors (toxic chemicals, altered flow, suspended sediments, nutrients, physical habitat alteration, and harvest pressure). This analysis identified nutrient enrichment, dissolved phosphorus in the freshwater ponds and dissolved nitrogen in Waquoit Bay, as the dominant stressor within the watershed. The Risk Analysis Phase of this project contracted with the Boston University Marine Program (BUMP) to develop a coupled Nutrient Loading Model (NLM)/Estuarine Loading Model (ELM) which predicted dissolved inorganic nitrogen (DIN) concentrations in the bay from nitrogen loading from the watershed based on nitrogen input from the atmosphere, fertilizer use, and septic systems.
A hypothetical management application of the NLM/ELM models suggested that nitrogen loading from the watershed would have to be reduced from the current 28 Kg N/ha yr to 21 Kg N/ha yr in order to achieve the 30% coverage of eelgrass in the bay proper which occurred in the early 1970's. Another potential management application examined the impact of nitrogen loading on the disappearance of the bay scallop populations in the early 1980's. It appears that eelgrass cover is a more sensitive indicator of nitrogen enrichment than is bay scallop harvest levels.
D. Ford1, Sharon A. MacLean2, and Jerome Prezioso2
Measurements of salp (Tunicata, Thaliacea) populations on the Northeast Continental Shelf have revealed information about the spatial and temporal trends of these grazers. A long time series of plankton measurements taken by the National Marine Fisheries Service provided an unprecedented collection of observations to analyze. Abundance and distribution of salps (enumerated as Salpidae and Thaliacea) has been determined from an approximately 24-year time series, from 1977 to the present, of species abundance measured by Bongo net tows taken on the Northeast Continental Shelf. Monthly, the highest concentrations of salps occurred between July and November. The Northeast Continental Shelf study area (approximately 35N-46N, 66W-77W) was divided into four regions (Middle Atlantic Bight, Southern New England, George's Bank, Gulf of Maine). A meridional trend is revealed with higher concentrations in the southern regions. We find several events of extreme salp concentration throughout this time series. Some events had a peak salp concentration of ~1 x 104 specimens * m-3. The dynamics (location, magnitude, and duration) of these events are explored as well as the relationships between accompanying physical oceanographic measurements.
Donna L. Johnson
Gear comparisons were made of the catching efficiencies between the 1m2 Multiple Opening-Closing Net and Environmental Sensing System (MOCNESS) and the paired 0.61m Bongo sampler, as part of the GLOBEC Broadscale surveys on Georges Bank. Monthly surveys were implemented from January through June of 1996 and 1997. The bank-wide assessment provided the necessary information on distribution, abundance, growth and mortality/survival estimates of key ichthyoplankton species.
Differential rates of capture by year, season, depth, and light regime revealed significant differences between the two samplers. Ratios of the mean standardized catches under 10 m2 of sea surface area indicate a 4:1 difference in capture between the MOCNESS versus Bongo sampler. For all survey stations in which both sampling gears were deployed, larval fish were captured at 350 MOCNESS stations (97% occurrence) while the Bongo stations contained larval fish at 345 stations (96%) occurrence. Analysis of individual taxa revealed significant differences in the catch ratios in 13 of the 15 species examined.
Zooplankton plays a key role in marine ecosystems, both as a link between primary producers and higher trophic levels and as a major prey item of larval fishes. This poster presents information describing the distribution, annual cycle, and interannual variability of zooplankton biomass within the Northeast Shelf ecosystem for the years 1977 – 2000. Additionally, early spring zooplankton standing stock levels from 1972 -2000 were compared to the North Atlantic Oscillation (NAO), an index of atmosphere variability over the North Atlantic Ocean.
Catherine A. Kuropat1,
Renee Mercaldo-Allen1, Elaine M. Caldarone2,
Ronald Goldberg1, Beth A. Phelan3, and Frederick
This study evaluates white muscle tissue RNA concentration as an indicator of short-term fish growth. Young-of-the-year winter flounder (Pseudopleuronectes americanus) and tautog (Tautoga onitis) were grown in short-term caging experiments (1994-1995) within three north Atlantic estuaries and five habitat-types. RNA concentration (mg/mg wet tissue wt.) was significantly correlated with instantaneous growth rate in winter flounder, measured as length (r=0.83) and weight (r=0.79) and in tautog, measured as length (r=0.69) and weight (r=0.73). Estuary-and habitat-specific differences in growth rate, as determined by RNA concentration, were similar to those determined by measuring instantaneous growth. These results validate the use of RNA concentration as an indirect measure of growth in young-of-the-year winter flounder and tautog.
Amy Renner1, Tim
V.N. Cole1, Dana L. Hartley2, Blair
Mase3, and Pat Gerrior2
The Critical Sightings Program (CRISP) placard has been developed to facilitate more comprehensive and real-time reporting of offshore sightings of right whales, and entangled or dead whales of any species. The placard was designed primarily for use by the U.S. Coast Guard. However, it is available to other federal and state agencies whose activities are likely to encounter marine mammals, including the Department of Defense Marine Mammal Awareness Program (where the placard is posted on their website). The placard is not intended for use by merchant or other civilian vessels.
The placard is laminated with information on both sides about reporting strategies and identifying whales. We have an agreement from the U.S. Coast Guard to keep the placard on the bridge of all Coast Guard vessels and Coast Guard Stations from Maine to Texas. The placard is also being distributed to any interested state and research organizations.
Erin Livensparger and
Ruth E. Haas-Castro
Accurate age and growth information
is essential for the successful management of any fish population.
The NEFSC's Atlantic Salmon Research and Conservation Task (ASRC) uses
Optimas 6.5.1 to efficiently extract growth and age information from
Atlantic salmon scales. Optimas is an image analysis software program
that enables measurements to be extracted from digital or real time
video images. For endangered Atlantic salmon populations we typically
age the fish using scales and
First observed in bivalve mollusc larvae at Milford over forty years ago this phycomycetous fungus appears to be endemic in cultures of bay scallop larvae at this laboratory. It completes its brief life cycle in affected larvae. Biflagellate zoospores released from mature thalli are infective. Clonal cultures have been obtained from scallop larvae and maintained successfully on enriched seawater agar. In limited experiments, this fungus appears to cause heavy mortality under simulated hatchery conditions.
David B. Packer1,
Joseph J. Vitaliano1, and Carl Alderson2
Few scientific studies have focused on restored salt marshes (restored because of a severe environmental impact) as opposed to created or constructed marshes (created in response to mitigation). In 1990, a 576,000-gallon oil spill seriously damaged marshes of the Arthur Kill, the strait separating Staten Island, NY from NJ. The Salt Marsh Restoration Team of NYC Parks implemented a multi-year restoration and monitoring project to restore marshes directly impacted by the 1990 spill. To date, restoration activities included the successful reintroduction of over 9 acres of Arthur Kill-propagated salt marsh cordgrass, Spartina alterniflora. SMRT has been monitoring several parameters in oiled marshes that were replanted and oiled marshes left for natural recovery, including Spartina biomass/density, ribbed mussel (Geukensia demissa) density, fish abundance/diversity, frequency/duration of feeding of wading birds, and sediment total petroleum hydrocarbons (TPH) in replanted and unplanted sites. In 1996 the National Marine Fisheries Service’s James J. Howard Marine Sciences Laboratory extended the study by characterizing and assessing the structure and function of replanted, unplanted, and reference marshes. Studies included sediment chemistry, contaminant analyses, macrobenthic surveys, and stomach content analyses of mummichogs (Fundulus heteroclitus). Results are presented from the two investigations. A quantitative assessment of these marshes may allow us to evaluate our ability to restore this habitat’s functional attributes, and identify indicators of habitat and living resource health and recovery within a heavily urbanized and degraded estuary.
Jerome Prezioso and Joseph
Seasonal abundance of Temora longicornis from four regions of the northeast continental shelf were plotted with Surfer using MARMAP and Ecosystem Monitoring Bongo tow data from the years 1977-2000. Maximum abundance for this neritic species was in the coastal waters of the Middle Atlantic Bight (MAB) in the late spring. Temora longicornis also reached peak abundance during late spring in Southern New England, (SNE) Georges Bank, (GB) and Gulf of Maine, (GOM) but with the numbers decreasing with increasing latitude. The lowest abundances were found in early autumn in the MAB and SNE, in winter on GB and in early spring in the GOM.
For 11 years, the NOAA CoastWatch Program has processed and distributed NOAA’s satellite remote sensing products to researchers and environmental managers throughout the continental U.S., Alaska and Hawaii. Given the wide range of environmental conditions and ecological issues that occur within U.S. coastal waters, 8 regional CoastWatch nodes were established where the further development of remote sensing products would address local management concerns.
With advancements in computer hardware and software, and the cumulative expertise within the CoastWatch Program, environmental satellite data and image products have reached a high level of quality, versatility and timely production. This poster presents a sample of the products that have been developed for the northeast U.S. coastal ecosystem and descriptions of how they are being used.
John J. Ziskowski1,
Holly Hansen2, Jose J. Pereira1, Marianne Farrington3,
Jay M. Burnett4
An X-ray study of 390 winter flounder collected from Boston Harbor and Georges Bank in 1989, 1992, and 1995 has revealed the presence of eight types of deformities of the vertebral columns of affected fish: accessory processes, spinal curvature, complex-vertebrae, reduced-accessory processes, fused vertebrae, deformed centra, deformed accessory processes, and reduced centra. LOGISTIC REGRESSION testing of the overall axial skeletal anomaly prevalence, done simultaneously for the predictor variables: LOCATION, SEX, AND AGE shows that the 33.1% prevalence in Boston Harbor flounder is significantly higher than the 14.7% prevalence found in Georges Bank fish (P = 0.000). Only the first four deformities listed above, however, occur at significantly higher prevalences within Boston Harbor fish; i.e., at P < 0.05 levels. Although an excess number of deformed flounder were found in Boston Harbor, we explored the contributions of SEX and AGE as predictor variables since flounder catches from both locations were composed of fish with differing ages and sex, introducing statistical bias. Fitting a CLASSIFICATION TREE to this multi-variate date base elucidated relationships between DEFORMITY OCCURRENCE, LOCATION, SEX AND AGE, showing that older female flounder from Boston Harbor were most affected by axial skeletal deformities. A DISEASE INTENSITY INDEX based on the deformity “counts” and “types” for affected fish was determined. Using POISSON REGRESSION testing as well as fitting REGRESSION TREES to this multi-variate data base, it was found that DEFORMITY INTENSITY INDICES are not necessarily higher within Boston Harbor flounder compared to fish collected on Georges Bank. Index values are higher in younger males from Boston Harbor, but the magnitude of the deviance of the POISSON REGRESSION is too great and the variables DISEASE INDEX, LOCATION, SEX, AND AGE are not well-modeled, in this case.