CINEMar/Open Ocean Aquaculture Annual Progress Report for the period 1/01/03 through 12/31/03

Principal Investigator(s): Larry G. Ward, Raymond E. Grizzle, David W. Fredriksson and James D. Irish

I. Accomplishments

A. Scheduled Tasks
The University of New Hampshire Open Ocean Aquaculture (OOA) Environmental Monitoring Program objectives and tasks for 2003 include the following.

1.) Routine field monitoring of the water column and substrate at and near the OOA field site to comply with permitting needs and to address environmental concerns. This includes quarterly sampling surveys to monitor: benthic infaunal characteristics (box coring); epifaunal characteristics (bottom videography); sediment organic levels; water quality (particulate matter concentrations, chlorophyll, and dissolved nutrients); and physical characteristics of the water column (e.g., salinity, temperature, dissolved oxygen, and light transmission,). Use this information to determine if there are impacts to the substrate, benthic community, and water column that can be attributed to aquaculture activities by assessing factors such as biodiversity and abundance of infaunal and epifaunal communities, sediment organic buildup, or detectable changes in concentrations of particulate matter or dissolved nutrients.

2.) Deploy, maintain and upgrade environmental monitoring instrumentation (in situ) at the OOA field site. This includes sensors that will provide high-resolution observations of critical environmental parameters (e.g., waves, water temperature, salinity, dissolved oxygen, or fluorescence) as required by the OOA program.

3.) Monitor occurrence of listed marine species in the OOA field area.

4) Develop and implement information transfer protocols that will make the environmental monitoring database readily available to all project participants, federal and state regulating agencies, and other interested parties.

5.) Develop new, streamlined, less expensive monitoring programs that will comply with permitting and environmental needs and be at a scale appropriate for private OOA enterprises.

B. Progress on Tasks
1. Assessment of Bottom Sediments, Benthic Infauna and Epifauna, Water Quality, and Physical Characteristics of the Water Column.

Bottom Sediments and Infauna
Four monitoring cruises at the aquaculture field site (Figure 1) were conducted during the 2003 reporting period (January 15th, May 7th, August 11th, and December 9th). During each cruise bottom sediment samples were taken at eight permanent monitoring stations (Figure 2) established in late 2001. These stations were set in an array that placed four sites in close proximity to the fish pens and mussel line and four control stations that had similar depth and sediment composition as the potentially impacted areas. During the last two cruises, slight adjustments were made to two stations due to the movement of the fish pens in late spring 2003. However, the changes were minimal and did not affect the overall sampling strategy or analyses. In addition to the quarterly monitoring of the seabed described above, a one-time sampling of 13 additional (to the fixed eight) sites was conducted in July 2002. This program was designed to provide information on spatial variation in benthos and sediments in the general study area in order to better assess the adequacy of the eight permanent monitoring sites. These samples were processed and the resulting data analyzed during 2003.

Bottom sediments from each station were sampled with a box corer (Wildco) with a design sampling area of 0.0625 m². Subsequently, the sediment sample inside the box corer was subsampled for infauna with a 10.4 cm ID (0.0085 m²) acrylic core tube. A portion of the remaining sediment was stored in a sterile plastic bag for particulate organic analysis and for archiving (for grain size analysis if needed in the future). The samples were processed for infauna in the field by washing the entire box corer sample contents (less subsamples) onto a 5 mm mesh sieve and each core subsample onto a 0.5 mm mesh sieve and fixing sieve residues in 3 to 5% formalin with rose Bengal. Subsequently, each sample was preserved in 70% isopropanol. In the laboratory the invertebrates were removed under 3x magnification, sorted by major taxa, identified (to family level in most cases), counted, and weighed (wet weight of preserved specimens). The organic content of the sediment samples was determined by loss-on-ignition (LOI). Each sample was dried, heated to 450° C for four hours and the weight loss determined (modified from Ball 1964).

Epifauna and Videography
Benthic epifauna was monitored in 2003 at the eight permanent stations (Figure 2) during four cruises (March 16th, May 14th, September 2nd, and October 18th) using a bottom camera system (Hubbard Camera). The Hubbard camera is composed of a video camera mounted on a frame with synchronized strobe lights. The camera can be towed near the bottom at slow speeds, as well as touch down, and obtain imaging of the surficial sediments and epifauna. Burrows and other indications of infaunal activity, as well as fish can also be obtained. Data recording and power supply are located onboard the research vessel.

Water Quality
Water samples were collected during each monitoring cruise at one or two locations (adjacent to the instrument buoy and close to the mussel line, Figure 2) and usually at two depths (5 meters and 45 meters). Each water sample was analyzed for total suspended sediment concentration, organic particulate content (LOI), and dissolved nutrients using similar methods as described in Strickland and Parsons (1968), Langan (1992), and Wolf and Langan (1992). During 2002, a new protocol involving sampling inside and downstream of the fish cages was conducted in an attempt to characterize the movement of organic material outside the cages. However, no differences were detected in any of the parameters measured. Therefore, in 2003 water quality was monitored as in previous years, adjacent to the buoy and the mussel line, but not inside the cages. During 2004, it is anticipated that a modified protocol of sampling inside and outside the cages will be conducted. The most effective protocol for characterizing the movements of materials through the cages is still being worked out.

Physical Characteristics
During each monitoring cruise physical characteristics of the water column (temperature, salinity, light transmission, fluorescence, dissolved oxygen and PAR - photosynthetically available radiation) were measured at the same stations water samples were collected to determine water quality characteristics. These physical parameters were measured with a SeaBird SBE-25 CTD data logger and associated integrated sensors. In addition, physical characteristics of the water column were observed near continuously at several critical depths via an instrumented buoy system (described below).

2. Moored Instrumentation Buoy
In order to provide higher temporal resolution than shipboard monitoring can provide an instrumentation buoy has been deployed at the field site since 1999 (Figure 2). During 2003 normal deployment and recovery operations and data collection activities occurred. However, progress to improve data quality and the capabilities of the instrumentation buoy to meet monitoring requirements remained as priorities. An updated schematic of the instrument buoy is given in Figure 3. The following lists improvements to the instrumentation buoy during 2003.

1. A SBE Dissolved Oxygen Sensor and pump was purchased and incorporated with the SBE16p located at a depth of 22 meters.
2. A flash card in the buoy data system was changed to 128 MB from 96 MB. This should increase the deployment time from 102 days of backup recording of wave and environmental data to 136 days (approximately 4.5 months), which exceeds the deployment time of the optical sensors without in-situ cleaning.
3. The wave measuring accelerometer was moved in the buoy down 13.5 inches so that it is closer to the center of gravity. This may help to reduce the effects of motion coupling when performing the data processing of the wave accelerations to obtain wave statistics. At the same time, it was noted that the Summit Instruments Accelerometer was not passing internal tests which indicated impaired performance. The accelerometer was replaced in Spring 2003 with a CrossBow sensor.
4. It was verified that the vertical acceleration channel of data was being transmitted over the radio after accelerometer rework.
5. A thermistor was added on the external cable that connects to the LiCor PAR sensor. However, during a test in the Spring 2003, it was determined that this system did work. A Gill style radiation shield was needed to remove the effects of direct solar radiation on the temperature. A radiation shield was borrowed from another project and will be mounted on the buoy on the radar reflector mount (about 2 meters above water level). Putting the radiation shield at the normal 3 meters height would add drag to the buoy. The additional drag would tilt the buoy, degrading the wave observations
6. A LiCor cosine Photosynthetically Active Radiation (PAR) sensor was attached to the buoy for a spring test. This sensor was mounted on the top of the mast (small weight and volume) to obtain first order estimates of downwelling irradiance (cosine collector aimed upward) that drives primary productivity (photosynthesis). However, no amplifier was attached to this device, and when converted to voltage with the suggested 2 k ohm resistor, the signal was in the millivolts range and not well matched to the data system A/D range. An amplifier has been constructed to make the PAR and the thermistor signals compatible with the 2.5-volt digitizer in the waverider, and these will be added during the winter 2003-2004 servicing.
7. A second serial channel was added to the buoy data acquisition system so additional instruments could be added to the data stream. The cabling was set up for this sensor, and an end cap with two underwater connectors were put on the bottom end cap. The data system is presently set up with four serial input port capability. One is used for the GPS receiver, one for the buoy mounted MicroCat, and one for engineering diagnostic output during software development. This channel and the fourth channel are available for additional data logging. This has been implemented in software and is now returning blank information in the second serial position as well as the air temperature and PAR channels.
8. Previously, the possibility of adding a coilcord around the elastic tethers to allow data below the elastic tethers to be incorporated in the telemetry stream was investigated. This is an engineering test of a developing technique that has not been tried before on elastic tethers, but has been successfully used in compliant rubber hose deployments. The components (coilcord and elastic tethers) are available from WHOI and need assembly, connectors, and system integration. The design was done several years ago (Paul and Irish 1998), the materials collected, but no project was appropriate for testing until this environmental observational mooring. The components were brought out of storage, and checked and appear in good shape.
9. Revision of the buoy data acquisition software so that the system will continue to transmit environmental data if it fills the flash card was a task slated for 2003. The accelerations will be lost, but data important for OOA operations will continue to be sent. However, this is now not critical because of the increase in the size of the compact flash card.
10. An additional acoustic “pop-up” release was attached to the bottom of the system on the ADCP frame (see Figure 3). The intent was to use this release so that during recovery operations the ADCP and anchor assembly could be pulled onto the vessel without having to detach any of the components. This makes the recovery operations simpler and safer. However, there is a problem with the floats that are released at the bottom of the mooring rising to the surface without tangling in the rest of the mooring. When this happens, the middle of the mooring release can be triggered.

3. Monitoring of Marine Mammals and Sea Turtles
In order to monitor the occurrence of marine mammals and sea turtles in the vicinity of the OOA field site, databases provided by the Isles of Shoals Steamship Company and the Newburyport Whale Watch Company were utilized. This method was used last year as well and was described in our 2002 annual report (Ward et al. 2002). Briefly, from ~May to ~October trained naturalists went on whale watch cruises to identify and record locations and other data on the species sighted. At a minimum, the species and its approximate location were recorded for each sighting. These data were manually transferred to spreadsheet files and mapped using ArcView GIS software. Observations made during 2002 are reported below. The 2003 data have not yet been obtained from the whale watch companies.

4. Environmental Monitoring Information Transfer
As pointed out in last year’s annual report (Ward et al. 2002), the environmental monitoring and site description program has generated a large volume of observations concerning the benthic environment and the water column since the beginning of the project in 1997. Much of this information has been synthesized in project progress reports (e.g., Ward et al. 2001, 2002), an internal technical report (Ward et al. 2001), and outside publications (e.g., Ahern 2002, Grizzle et al. 2003). The internal reports are available on the OOA web site. In addition, a data archive has been constructed that stores much of the environmental data collected to date. However, a significant amount of data validation remains to be done. Ultimately, we anticipate making segments of the data archive that would be of general interest (e.g., benthos data, salinity, temperature, etc.) available to all interested groups via the Internet. In addition, several changes in data processing, archiving protocols and real time data transmission are planned to enhance the efficiency of the overall monitoring program and to provide easier access to the information base.

5. Refinement of Monitoring Protocols
No major changes in sampling protocols occurred during the reporting period; all continued as per the New Hampshire Fish and Game permit requirements.

C. Important Results or Findings
Bottom Sediment Organic Content
As discussed in previous Environmental Monitoring annual progress reports and Ward et al. (2001), the bottom sediments in the vicinity of the OOA field site are largely composed of low organic (usually <3% LOI), muddy sands. However, a number of bedrock outcrops occur in and around the field site that range in size from 10 to 100 meters across with elevations usually less than 5 meters. The outcrops often have gravel and cobble immediately surrounding them. In addition, extensive bedrock outcrops occur to the south and west of the field site. During 2003, the organic content of the bottom sediments at the eight permanent stations was measured during each of the four monitoring cruises to determine if any changes (or buildup) in organics occurred in the sediment in and around the fish pens or mussel line. The results, as in past years, show that the particulate organic fraction of the sediment remained low (typically less 3 % LOI), indicating no buildup of organics from the aquaculture activities occurred.

Infaunal Benthos
The number of fish in the cages remained at relatively low numbers during most of the reporting period. Of the 1600 halibut put in the north cage in September 2001, approximately 1100 survived through 2003. Three thousand haddock were put into the south cage in late 2002 and remained through 2003. A third cage was added to the site in September 2003 and stocked with 32,000 cod. Hence, for most of 2003 (and for all of the benthic samples and data that have been analyzed), relatively small numbers of fish were at the site. And as in previous reporting periods, no detectable impacts on the seabed as measured by changes in benthos and/or sediments were expected or observed.

For example, Figure 4 shows the spatial patterns for three infaunal community characteristics based on samples collected from July 1999 through May 2003 at the eight permanent sampling sites. As organic input initially increases to the seabed in areas with relatively low organic content (such as the present study site), total community density, wet weight, and taxonomic richness typically will increase as a result of increased energy flow through the community. Consequently, if organic waste deposition from excess fish food and feces was affecting the benthos, a pattern of increased densities, biomass, and taxa richness would be expected at the four "impact" sites (3, 4, 5 and 7) nearest the pens and mussel line (Figure 2). No such trends are evident.

This type of spatial analysis (Figure 4) using the entire 4-year dataset potentially masks temporal trends. To examine spatial and temporal variations separately, the infaunal data were plotted over time after segregation into two groups: "impact" sites (3, 4, 5 and 7) and "control" sites (1, 2, 6 and 8). In nearly all cases for all three community characteristics from July 1999 through May 2003 the means from the impact and control sites had overlapping 95% confidence intervals (Figure 5). This suggests no significant differences between the impact and control sites during the 4-year monitoring period, and it corroborates the spatial analysis. Other temporal trends probably not related to aquaculture activities, such as strong seasonal pulses of recruits in spring and fall most years, continued during 2002 and 2003 and were discussed in previous reports.

In addition to community-level assessments, changes in taxonomic composition of the infauanal communities were also examined. For this analysis, the 4-year dataset was divided into two groups: July 1999 - October 2001 (when few fish were present), and February 2002 - May 2003 (when more fish were present). The intent was to determine if the relative rankings of taxa at the study sites had changed during recent months when more fish were present. Nine of the top ten taxa were the same for the two periods (Table 1). The relative orders had changed for some taxa, but otherwise the same families of polychaetes, mollusks, and crustaceans have dominated the infaunal communities for the entire 4-year sampling period. This suggests that there has been no shift in community taxonomic composition associated with the aquaculture activities.

The final infaunal assessment completed in 2003 was an "intensive spatial monitoring" aimed at characterizing spatial patterns to determine if the eight permanent sampling sites were representative of the general study area, and thus adequate for detecting trends. Twenty-one sites (the eight permanent sites plus thirteen additional sites) were sampled in July 2002, and the samples analyzed in 2003. When the full range of values for each of the community-level measures was spread across five or six intervals, the majority of the samples fell within one range for all three measures (Figure 6). Hence, they had a relatively narrow range of densities, biomass, and taxonomic richness, suggesting that the eight sampling sites are representative of the infauna in the general area.

Videography and Epifauna
In addition to trouble shooting the mechanical problems that existed earlier in obtaining bottom videography at the OOA field site, a great deal of effort in 2003 was directed at trying to maximize the potential of using videography as a tool to monitor general bottom conditions and epifauna. These efforts included developing methods to review and capture images of key sites, quantifying information on bottom habitat and epifauna, and displaying the results. For instance, we investigated methods to quantify abundances of worm tubes and burrows, trace markings (tracks and trails), mollusk shells, and other epifauna, as well as describing sediment characteristics. We anticipate expanding these efforts in the next reporting period.

Initial inspection of the video images indicated that the habitats and epifauna at the eight monitoring stations showed some variability between stations, but no obvious changes occurred at a station. However, these observations still have to be verified. Examples of bottom images that were extracted from the video from each monitoring station for the cruise conducted on October 18, 2003 are shown in Figure 7.

Water Quality
Water quality measurements made thus far in the monitoring program have been typical of nearshore Gulf of Maine waters (e.g. Townsend and Christensen 1992, Benway 1997). For example, particulate organic matter (POM) concentrations during 2003 ranged from <1 mg/L to 3.4 mg/L, and all chlorophyll a concentrations were <6 _g/L (Table 2). Highest concentrations in most parameters measured occurred in spring, reflecting the spring phytoplankton bloom typical in this area. The values for all parameters measured in 2003 were similar to measurements made in previous years, and again no impacts of the aquaculture activities were detected. It should be noted, however, that a modified water quality monitoring protocol is anticipated for 2004 to attempt to better characterize potential impacts of the increased numbers of fish at the site.

Water Column Physical Characteristics
Vertical profiles of several physical characteristics of the water column were taken during the monitoring cruises to provide more detail on variations with depth. In general, the vertical profiles taken in 2003 generally agree with the observations from the instrumentation buoy (discussed below). As expected, the water column in winter was cold (<5° C), salty (~33 psu), relatively clear (>75% light transmission) and vertically mixed as indicated by salinity, temperature, and transmissometer profiles on January 15th (Figure 8, Figure 9 and Figure 10). By May the surface salinity decreased and the surface temperature increased resulting in the water column becoming stratified. These changes were attributed to warmer air temperatures and higher freshwater discharge from coastal rivers. Also in May the clarity of the water column decreased with depth, likely the result of increased phytoplankton productivity. This was indicated by the flourescence profiles as well. However, flourescence is not reported here as calibration questions exist and absolute values are in question. Nevertheless, relative increases in flourescence with depth roughly co-vary with decreases in light transmission, indicating the role of primary productivity. The flourescence calibration will be assessed in the next reporting period. In summer, heating of the surface water continued. As a result the thermocline strengthened and deepened to ~18 meters. Surface temperatures on August 11th exceeded 17° C and salinities near the surface increased from May to over 31 psu. By December, the water column had cooled (~6° C), the salinity had increased (approaching 33 psu), and the water column had become vertically mixed. In addition, the light transmission profiles on December 9th were extremely low for the New Hampshire inner shelf decreasing well below 60% from surface to bottom. These very turbid water conditions were attributed to the strong winds that occurred for several days prior to the cruise, likely causing a resuspension event and increased shelf circulation. This event will be examined more closely in the next reporting period. During the four cruises in 2003 dissolved oxygen was measured with the SeaBird 25 system throughout the water column. Earlier work has shown that the sensor is experiencing calibration problems resulting in consistently underestimating the DO concentrations. Consequently, these data are presently being verified and the error being assessed. The results of this effort will be discussed in subsequent reports.

Observations From The Instrumentation Buoy
Over the past year the instrument buoy was deployed five separate times. The deployment and recovery dates are provided on Table 3. These deployments represent data sets 4 through 8 since the system was first established in December 2001. A typical deployment period is approximately three months. The first deployment of 2003 was relatively short (1/23/03 - 1/31/03) because of telemetry issues most likely due to icing causing the data system to malfunction (see Figure 11).

The individual instruments deployed during 2003, along with their position in the water column, sample rate and real-time transmission capabilities are provided on Table 4. For the third deployment (data set #7) all of the instruments were setup with a higher sampling rate to attempt to capture internal wave events that were occurring at the site.

Temperature and Salinity
During the 2003 deployment period, temperature and salinity information was obtained from depths of 1 meter, 22 meters and 50 meters (Figure 12). In general, the data shows that the water column was well mixed from December, 2002 to the beginning of March, 2003. In March, the winter subsides and the surface waters become warmer with a lower salinity. One possible cause of the lower salinity is the winter melt and runoff of fresh water into the Piscataqua and other rivers in the region. By mid-July, the water column is fully stratified. Steady cooling of the water column begins in August. By October, the surface and mid-water column temperatures are similar and by November, the water column, is again fully mixed. Variability in the surface salinity throughout the year could be the result of a combination rain events and/or air entrainment in the conductivity cell.

Fluorescence and Turbidity
The SeaCat SBE16p deployed at a depth of 22 meters recorded the optical backscatter (turbidity) and chlorophyll-fluorescence. The data sets obtained from both the Sea Point fluorometer and turbidity sensors are shown on Figure 13. The techniques to measure fluorescence and turbidity in the water column are not as straightforward and robust as those for temperature and salinity. Since both of these measurements are performed using optical techniques, any growth (bio-fouling) and/or obstructions of the instruments can affect the measurement. An example of bio-fouling on the instrument is shown on Figure 14. It is difficult to correct for this kind of measurement with post-cruise calibrations. Typically, field calibration is required to obtain quantifiable results. Some discrete fluorescence samples were taken at 5 and 45 meter depths and are also shown on Figure 13.

Dissolved Oxygen
In January, 2003 a SBE dissolved oxygen (DO) sensor was purchased (S/N 0385) as part of the OOA Monitoring program for use with the SBE 16plus instrument deployed at a depth of 22 meters. The DO sensor was connected to a SBE 5M submersible pump plumbed to the conductivity cell so that fresh samples of ocean water were available during measurements. The first deployment of the instrument was on January 23, 2003. Refer to the 2003 deployments particulars on Table 5. Due to telemetry system malfunctions, the buoy was recovered to investigate the problem. At that time, data from all of the instruments were downloaded and examined. It was found that the DO sensor (S/N 0385) was consistently reading about 35% too low. Since the buoy was scheduled to be redeployed in a matter of days, the same DO instrument was used. In the meantime, a replacement DO sensor (S/N 0090) was obtained from SBE. In late April, the buoy was recovered and DO sensor S/N 0385 was replaced with sensor S/N 0090. The faulty instrument was sent back to the manufacturer and it was determined that the sensor membrane was bulged out due to overpressure from freezing just prior to deployment. The data collected with the instrument, however, was processed using post-deployment calibration coefficients. The DO sensor S/N 0385 was returned fully functional and redeployed on July 31, 2003. Note that during this deployment, the sampling rate was increased from every 900 seconds to every 60 seconds in an effort to capture information regarding internal solitary waves that were moving through the system. The DO data for 2003 are shown on Figure 15.

Acoustic Doppler Current Profiles
Also included on the mooring for the past year was an upward looking, 300 kHz, RD Instruments (RDI) Workhorse, Acoustic Doppler Current Profiler (ADCP). The ADCP was programmed to measure Northgoing and Eastgoing (and Vertical) velocities at 2 meter bins ranging from the depth of 3.3 to 49.3 meters. The basic statistics including the maximum, minimum, mean and standard deviation for each of the Eastgoing and Northgoing components at each depth are provided on Table 6. The information from data set #7 was not included since the sampling frequency on the ADCP was different in an attempt to capture possible internal waves occurring at the site. Notice that the top 6 bins show data sets that were “noisy”. Keep in mind that the individual data sets can be edited, however, so not all of the information is lost. A major source of the “noise” is sidelobe reflections off the water surface and buoy which can contaminate the Doppler velocity estimations. Also, the range of the instrument is dependent on the tides that go up and down relative to the instrument, which is somewhat fixed relative to the bottom.

Surface Waves
Accelerometers, located in the well of the buoy, are used to infer surface characteristics of the waves, assuming that the system follows the wave in the vertical direction (see Ahern 2002). The accelerometer measurements are processed in a similar manner as the data sets obtained from the wave buoys of the National Data Buoy Center (NDBC). For 2003, the significant wave heights measured at the OOA site are shown on Figure 16.

Internal Solitary Waves
Over the past couple of years, operational staff working at the OOA site observed conditions characteristic of internal solitary waves. To capture the effect, the buoy instruments sampling frequency were increased to once every minute for deployment #7 during summer 2003. The following discussion describes the results and provides an explanation of possibly what is occurring at the site.

In the coastal ocean it is common to see interfacial waves on the pycnocline where the density structure may be nearly two layered ­ an upper mixed layer and a bottom mixed layer with a sharp interface between. In strong tidal regimes around sharp topographic relief, a special kind of interfacial waves - internal solitary waves, or solibores, are observed. These waves are generated at sudden bathymetric features such as the shelf break or over banks. At the UNH OOA field site the nearest generation site could be Jeffrey’s Ledge where the shelf drops off into Wilkinson Basin. The vertical component of velocity created by continuity as the flow diverges with increasing depth, distorts the density field converting the kinetic energy of tidal flow to a potential energy “depression” in the density field. When the tidal velocity is greater than the group velocity of these disturbances, the energy can not propagate back onto the shelf, so the disturbance grows. When the tidal velocity does reverse, the depression propagates up onto the shelf. Due to non-linear effects, these single depressions grow steeper on the front, and less steep on the back with a series of “bumps” and eventually develop into a series of rank ordered depressions.

The velocity structure associated with these is onshore in the upper layer and offshore in the lower layer, which is preceded by downward velocity and followed by upward velocity as each pulse passes. At the OOA site, the upper layer is generally thinner than the lower layer so the waves will be waves of depression (downward pulses). Therefore, a temperature record at mid-depth would show spikes of warmer water caused by the downward velocity carrying warmer, surface water. Sometimes the return to pre-soliton conditions takes several hours, indicating some more lasting effects (mixing) due to the non-linear nature of the solitary waves.

After an analysis of tidal velocities (Irish and Paul 2003) it was thought that solitons would not be generated near the site as the 5 cm/sec tidal velocities were much lower than the 50 to 100 cm/sec solitary wave group (packet) velocities (based on the typical density structure in the Gulf of Maine). However, divers and ship operators reported observing strong surface currents (several knots) for short periods of time. Therefore, during August 2003 (when the density stratification and internal solitary wave signals would be the strongest), the environmental monitoring mooring was deployed for one month with all sensors sampling at 1-minute intervals (as fast as possible for the ADCP and mid-water SeaCat). The resulting data were then analyzed for internal solitary waves.

To address the question of generation site, satellite images were studied (Figure 17, Sawyer and Appel 1976). It soon became obvious that the generation site is across the Gulf of Maine along the Northern flank of Georges Bank. There are strong tidal currents (near 1 m/s) there due to the near resonance of the Gulf of Maine/Bay of Fundy system with the semidiurnal tide (Garrett 1972, Moody et al. 1984). The steep northern flank contributes to a strong downward velocity (due to continuity) that creates a strong internal solitary wave that propagates up onto the bank and also NNW across the Wilkinson Basin to the OOA site. Therefore, the small local tidal currents over Jeffreys Bank have little to do with the generation of the observed solitary waves. The propagation velocity calculated by the distance between packets of solitary waves from the satellite photos is about 0.75 m/s, which is in good agreement with the velocity as estimated from oceanographic conditions in the Gulf of Maine.

The observed temperatures (Figure 18) from the three SeaCats on the environmental mooring at the start of the deployment show no indication of warm ”pulses” of water at the top and bottom, but at the 22 meter depth do show significant pulses (up to 5° C) of warm water. This mid-water sensor is ideal to capture the vertical motion as observed by vertically advected water. Warm water implies internal solitary waves of depression, which is consistent with the historical density profiles in the region (Ward et al. 2001). The velocity records from 11 meter depth during the same period (Figure 19) show velocity pulses at the same time as the temperature pulses. The Northgoing (red) is the strongest while the Eastgoing (blue) is slightly weaker and negative indicating the upper layer is moving NNW, which is consistent with the direction of the wave front propagation as observed from the satellite photo in Figure 17. There are also stronger vertical velocities at the times of the solitons, although much smaller than the horizontal.

A blowup (Figure 20) of the packet of pulses observed on the morning of August 3, 2003 (containing the strongest velocities observed) indicates a typical, but “clean” suite of pulses. They are ordered with the largest pulse and longest wavelength first. The individual pulses in the packet are about 25 minutes apart and about 8 minutes in duration with something like 6 pulses per packet. A velocity profile of the first (and largest) pulse (Figure 21) shows the typical largest velocities in the thinner upper layer and smaller velocities in the thicker lower layer, with minimum velocities at the pycnocline. In this case, the depth of no horizontal motion occurs about the depth of the mid-water SeaCat (22 meters). The minimum velocities are located about the depth of the moored fish cages. Consequently, the drag will not be as large as if the cages were located at the surface or deeper in the water column. Extrapolating the velocity curves to the surface (not measured reliably by the ADCP because of sidelobe reflection interference from the surface) results in velocities on the order of 0.75 m/s or greater, which is consistent with observations.

The details of the observed internal solitary waves can be seen in Figure 20. The red trace is the Northgoing velocity, and the blue the eastgoing velocity at 11 meters depth (in the upper layer). The cyan curve that nearly agrees with blue eastgoing, is really the northgoing component in the lower layer (41 meters depth). Therefore, the lower layer is going in the opposite direction as the surface layer, and with lower speed as should be because the layer is thicker (conservation of velocity transport). The magenta curve just under the red one is the temperature time series from the mid-water SeaCat and indicates the vertical displacement. The vertical velocity is shown by the green line. As the first pulse approaches, there is first a downward velocity which is accompanied by an increase in temperature as the warm water is advected downward. Then the NNW velocity in the upper layer and SSE in the lower layer increases. As the vertical velocity downward reverses and becomes upward, the temperature starts back down, and the maximum horizontal velocity (and shear) is observed. The same pattern is observed in the next few pulses. It is interesting that the velocity record shows a stronger signature of the internal solitary waves than the vertical displacement as indicated from temperature (or density) records.

This study shows that there can be strong internal solitary wave currents at the site, with maximum velocities much greater than 1 knot at the surface. There is a shear with deeper waters moving the opposite direction of the surface. These waves are strongest in the late summer when strongest stratification exists, and nearly non-existent in the winter when the water column becomes well mixed and cannot support freely propagating internal waves. The density profile has the pycnocline at the depth of the fish cages, indicating that they are located near the minimum horizontal velocity, so the effects on the fish cages at their down position will be much less than if they were at the surface. Although these are waves with oscillating movement, they are still low enough frequency (25 minute period) so that the fish cage and mooring will move to an equilibrium position (drag on the fish cage equaling mooring tension in disturbed position) before the wave has passed. This is unlike the surface waves which just move the fish cage about in its mooring with little translational result. Therefore, internal solitary waves can provide high currents at shallow and deep depths, they are observed on most coasts of the world, and their effects can be stronger than the tidal and wind driven currents (as was the case at the OOA site), and need to be considered for offshore aquaculture.

Listed Marine Mammals and Sea Turtles
The occurrence of listed marine mammals and sea turtles in the region and the OOA field site from early spring to fall 2002 are shown in Figure 22 and Figure 23. During this period, only two sightings of any listed species were made within 5 km of the study site. Fin and humpback whales were frequently sighted in the general area, but most sightings were 5 km or more from the aquaculture site. Data from 2003 have not been processed, but thus far it appears that listed whales and turtles do not frequent the study area.

D. Difficulties Encountered
Difficulties with the calibration and reliability of the dissolved oxygen sensor on the SeaBird SBE25 CTD system remains a problem. We intend to alter our monitoring methods for DO in response to these issues. In addition, maintaining and trouble shooting the real-time telemetry system on the instrumentation buoy has presented some problems that are being addressed.

E. Anticipated Success in Meeting Project Objectives on Schedule
We expect to accomplish all tasks and objectives of the project within the scheduled time frame.

F. Reports, manuscripts, and presentations resulting from the project
Grizzle, R.E., L.G. Ward, R. Langan, G.M. Schnaittacher, J.A. Dijkstra, and J.R. Adams. 2003. Environmental Monitoring at an Open Ocean Aquaculture Site in the Gulf of Maine: Results for 1997-2000. Pp. 105-117. Open Ocean Aquaculture: from Research to Reality. Eds: C.J. Bridger and B.A. Costa-Pierce. The World Aquaculture Society, Baton Rouge, LA, USA.

Irish, J.D. and D.W. Fredriksson. 2003. Compliant Mooring Technology to Separate Buoy Motion from In-line Current Meter Observations. Proceedings of the IEEE Seventh Working Conference on Current Measurement Technology, San Diego, California, USA.

Ward, L.G. 2003. Sedimentologic and stratigraphic studies on the New Hampshire inner shelf. Geological Society of America Abstracts With Programs, volume 35, number 6.

II. Tasks and Activities for Next Reporting period

A. Tasks for the next reporting period
The objectives and tasks discussed in section I.A. of this report will continue through the next reporting period. However, it is anticipated that all monitoring protocols will continue to be refined within the requirements of the existing New Hampshire Fish and Game permit to more effectively detect any environmental impacts from the aquaculture facility. In addition, the monitoring program is in the process of being reviewed for permitting by the Unites States Environmental Protection Agency. The existing program will be modified, if necessary, to meet any new permitting requirements.

Below are some of the areas where we are considering modifications to the 2003 program.

Videography
We will continue to develop and use bottom videography to assess epifauna and general bottom conditions. We anticipate we will utilize this technology more extensively for monitoring purposes during the next reporting period.

Water Quality
We intend to modify the sampling protocol implemented during the present reporting period by sampling inside and outside downstream of the fish cages. The aim is to better characterize dispersion of materials from the site under different combinations of conditions.

Instrument Buoy
The instrument buoy and data management protocols are still being developed and upgraded. Therefore, a number of modifications are planned. Anticipated improvements and upgrades during the next reporting period include the following.

• Addition of air temperature at 2 meters elevation in radiation shield
• Addition of PAR down-welling irradiance sensor on the mast
• Testing of coil cord telemetry of the 22 meter observations
• Improvement of the telemetry link with new radios, high gain directional antennas, and synchronized shore based radios allowing hourly data to be reliably displayed on the Web.
• Recalibration all of the instruments

B. Brief work plan to accomplish tasks
Anticipated funding levels should allow us to implement the changes described above as part of the routine monitoring program.

C. Anticipated concerns or difficulties
None.

III. Expenditures
All expenditures for the reporting period were within anticipated levels.

References
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Benway, H.M. 1997. An Investigation of the Nutrient Dynamics of Jeffreys Basin: a Seasonal Nutrient Trap. M.S. Thesis, University of New Hampshire, Earth Sciences.

Garrett, C.J. 1972. Tidal Resonance in the Bay of Fundy and Gulf of Maine. Nature, 238: 441-443.

Grizzle, R.E., L.G. Ward, R. Langan, G.M. Schnaittacher, J.A. Dijkstra, and J.R. Adams. 2003. Environmental Monitoring at an Open Ocean Aquaculture Site in the Gulf of Maine: Results for 1997-2000. Pp. 105-117. Open Ocean Aquaculture: from Research to Reality. Eds: C.J. Bridger and B.A. Costa-Pierce. The World Aquaculture Society, Baton Rouge, LA, USA.

Irish, J.D., and W. Paul. 2003. Monitoring of Offshore Aquaculture Systems, Phase I. In CINEMar, Open Ocean Aquaculture Demonstration Project, Annual Progress Report, Calendar Year 2002, January.

Langan, R. 1992. UNH JEL Standard operating procedure for water sampling for suspended solids, chlorophyll, and nutrients. JEL SOP 1.05. In: Standard Operating Procedures and Field Methods Used for Conducting Ecological Risk Assessment Case Studies. Mueller et al. (eds.) USEPA, US Navy (NRaD) Technical Document 2296.

Moody, J.A., B. Butman, R.C. Beardsley, W.S. Brown, P. Daifuku, J.D. Irish, D.A. Mayer, H.O. Mofjeld, B. Petrie, S. Ramp, P. Smith, and W.R. Wright. 1984. Atlas of Tidal Elevation and Current Observations on the Northeast American Continental Shelf and Slope, U.S. Geol. Survey Bul. 1161.

Paul, W. and J. Irish. 1998. Providing Electrical Power in Conjunction with Elastomeric Buoy Moorings. Proc. Ocean Community Conf. ’98, pp. 928-932.

Sawyer, C. and J.R. Apel. 1976. Satellite Images of Ocean Internal-Wave Signatures. U.S. Dept. of Commerce, NOAA Pub. NOAA S/T 2401.

Strickland, J.D.H. and T.R. Parsons. 1968. A Practical Handbook of Seawater Analysis. Fisheries Research Board of Canada, Ottawa.

Townsend, D.W. and J.P. Christensen. 1992. A nutrient trap in the Western Gulf of Maine. Proceedings of the Gulf of Maine Scientific Workshop, Woods Hole Oceanographic Institution.

Ward, L.G., R.G. Grizzle, and D.W. Fredriksson. 2001. UNH OOA Environmental Monitoring Program Annual Progress Report. UNH/NOAA CINEMar OOA Internal Report.

Ward, L.G., R.G. Grizzle, D.W. Fredriksson, and J.D. Irish. 2002. UNH OOA Environmental Monitoring Program Annual Progress Report. UNH/NOAA CINEMar OOA Internal Report.

Ward, L.G., R.E. Grizzle, F.L. Bub, R. Langan, G. Schnaittacher, and J.A. Dijkstra. 2001. Site Description and Environmental Monitoring: Report on Activities from Fall 1997 to Winter 2000. UNH/NOAA CINEMar OOA Internal Report Internal Document.

Wolf, J. and R. Langan. 1992. UNH JEL Standard operating procedure for water sampling for analysis of seawater samples for phosphate using wet chemistry. JEL SOP 1.08. In: Standard Operating Procedures and Field Methods Used for Conducting Ecological Risk Assessment Case Studies. Mueller et al. (eds.) USEPA, US Navy (NRaD) Technical Document 2296.