4 April 2001 DRAFT proposal to NEC for "eMOLT
Phase II: Salinity"
(Due in the mail on ~21 April )
Now, as we look toward the future of operational oceanography in the Gulf of Maine, we propose to monitor another physical quantity of potentially-equal importance: salinity. Given recent findings of source waters entering our region from the north, there is an obvious need to assess the influx of the fresher (low salinity) water mass as it is transported into and around the Gulf of Maine. Is there a detectable increase in the Canadian ice-melt waters? Will climate change have a significant effect on the conditions of our coastal waters? For purposes of monitoring the influences of advective water masses, salinity is a far more effective tracer. Given a set of YSI6000 probes (measuring temperature, salinity, and pressure) that are available from a previous study, we are asking for a relatively small amount of funding to simply refurbish these probes and buy a few new instruments with updated technology. Using first year money, we have already tested four of the YSI units with satisfactory results. Hence, as a natural extension of the project funded in year 2000, we now propose phase II: salinity.
As noted in the Phase I proposal, the primary objective of eMOLT is to document changes in the physical environment of our coastal waters. The biological consequences of these changes, though certainly important, are secondary to the focus of our investigation. While we intend to record and archive pertinent indices of lobster abundance, our efforts are directed at collecting background environmental data throughout the Gulf of Maine region (Figure 1).
Where temperature is a common environmental variable to measure, salinity is a subtle but potentially-important parameter which has been historically overlooked due to the expense and difficulty in monitoring. Since the time the Phase I proposal was written, more evidence of remote source waters affecting our waters have been published (Loder et al., 2001; Smith et al.,2001; and Houghton and Fairbanks, 2001). These papers provide further indication of low-salinity episodes transported from north to south. As denoted from Figure 2 (taken from Smith et al, 2001) periods of low-salinity appear for several months at a time and can be tracked at several locations along the coast (Mountain and Taylor, 1998). The objective here would be to extend this idea to include a few dozen sites within the Gulf of Maine. If this advective hypothesis holds true, empirical data alone may then help in forecasting the arrival these anomalous events at downstream locations. The effect of local river runoff also plays an important role in the interannual variability of salinity at many locations off the coast of Maine (Mountain and Manning, 1994) and the inner Mid-Atlantic Bight (Manning, 1991). The challenge remains however in differentiating these advective influences from the heating/mixing processes that take place locally. Studies have found a near-equal contribution from each of these processes (Mountain and Jessen, 1987) .
Studies by UNH zoologist have investigated the influence of salinity on local Homarus americanus. The Jury et al. (1994) tank study, for example, documented the sensitivity of lobsters (females in particular) to changes in salinity. Howel et al (1999) have provided further evidence for the females sensitivity to salinity. More recent heart rate studies have documented the sensitivity of lobsters to both temperature (Jury and Watson, 2001) and salinity (Dufort etal, 2001). Experiments have also been conducted in the field where tagged-lobster migrations were shown to occur in response to seasonal changes in water mass properties within an estuary (Watson, et al., 1999). We have coordinated the eMOLT Phase II proposal with that of Watson et al. and intend to merge datasets in a collaborative effort (see Dissemination of Results section below for descriptions of other projects closely tied to eMOLT).
Most of the remaining paragraphs on eMOLT "rationale" are taken from the Phase I proposal. While modified very little, they are included here for completeness. As with the rest of the proposal, the most important words or phrases in each paragraph are highlighted in bold font.
A network of strategically-located bottom temperature (and now salinity) records in the Gulf of Maine/Georges Bank region would make an important contribution to operational oceanography. Recent numerical modeling efforts to characterize the important physical processes of our coastal ocean are limited by a lack of near-bottom data for both initializing and validating simulations. Just as weather forecast modellers need a large expanse of data to initialize and assimilate the atmosphere, oceanographers will require continuous readings of temperature (and salinity) to monitor the mixing and advection of multiple source waters. Recent observational programs like GLOBEC and ECOHAB have documented numerous "anomalous" events due to unexpected displacements of water mass boundaries. These "events" are episodic in nature. In the case of Georges bank (Manning et al, 2001; Bisagni et al, 1996) the episodic residency of two water masses (Gulf Stream and Greenland ice melt origins, respectively) results in very dynamic living conditions for organisms residing in this area. In the case of the Maine coast (Lynch, et al. 1997, Mountain and Manning, 1994; Schofield et al.1998) variability is often related to a combination of upwelling/downwelling, river runoff, and influx of remote source waters. A long-term inexpensive monitoring strategy is necessary to document the frequency and extent of these events. While satellite imagery has provided a mechanism to describe the spatial variability and complexity of the thermal structure in our coastal waters it is hampered by clouds and fog in these areas and only provides a temperature associated with the very skin of the ocean. Deep near-bottom temperature has less bias associated with short term processes making it better suited as an indicator of longer-term climate variability than the seasurface value.
Understanding the relationship between bottom water properties and behavior of Homarus americanus off the coast of New England may be an important byproduct of this study. What are the scales of variability and what degree of variability can initiate a migration of the lobster population? Given the economic importance of Homarus americanus, very little seems to be known about what factors govern the distribution and migration of the New England stock. As reviewed by Factor (1995), there are only a few studies in the past decades that have specifically examined the dynamics of lobster habitats in the vicinity of the shelf edge. References are made to Cooper and Uzmann (1980), for example, who demonstrated an on-shore migration to warmer waters in the summertime after releasing several thousand tagged lobsters and recapturing 12%. These studies were conducted nearly thirty years ago. The hydrographic data that was used to correlate with lobster migration was a monthly-mean bottom temperature record averaged over a few decades (Colton and Stoddard, 1973). They conclude that the lobster migration maintains a 8-14 oC thermal regime. Can we resolve that range more accurately?
Much of the migration apparently is driven by the animal's life history and reproductive cycle. Peak hatching of stage 1 larvae occur at temperatures in the vicinity of 11-13.6o C bottom water (Fogarty and Lawton, 1983) resulting in planktonic surface concentrations in May through September. Harding et al. (1983) noted a 12.5o C surface temperature associated with the first arrival of stage 1 and other, more detailed, conclusions in all areas of its range. Larval release occurs in burst of up to 2000 individuals and results in swarms within the top two centimeters of the water column (Herrick, 1895). After about four molting cycles/stages the animal will reach its juvenile stage with carapace length increasing from 2-5mm. The rate of growth depends largely on temperature (faster in warm conditions) but this transformation generally occurs in less than a few months. MacKenzie (1988), for example, finds that stage 5 lobsters reared at 15o and 18o C had significantly greater dry weights and carapace lengths than those reared at 10o , 12o , and 22o C. In the wild environment, the highest survival rate is associated with rapidly increasing surface temperatures which provide a relative short planktonic period of life. While, "temperature is the most important factor affecting growth and survival of larval and postlarval lobsters" (Factor, 1995), high salinities >30PSU may be detrimental to lobsters in warm >20 water (Sastry and Vargo, 1977). The optimal salinity reported by Templeton (1936) is 30-31 ppt. Post-larval lobsters, however, have a tremendous swimming ability and are able to move to different environments with speeds of 15cm/s for up to five days resulting in 65 km excursions(Cobb et al, 1983).
What regulates the abundance and distribution of adult lobsters? Relationships of lobster concentrations to environmental factors cover a wide range of natural variability. Some reports such as Boudreau 1991, show relationships with windy conditions just after hatching and year class strength 8 years later. On the other hand strong stratification and thermocline trapping may expose post-larval lobsters to longer periods of predation. The dominant factor is not clear. Lobsters can sustain a wide range of temperatures -1 to 30 o C and abrupt changes of 16 o C (Harding, 1992). The temporal variation of lobsters at a single location is governed by the degree of movement. Movements come in the form of migrations, homing, and nomadism. Much of the information on migration of offshore lobsters comes from Cooper and Uzmann reports on tagging experiments in, for example, 1971 and 1980. as well as Fogarty et al. (1980). The overwintering strategy offshore tends to keep the animals in preferred temperature range of 8-14 oC. Uzmann et al. 1977 estimates migratory speeds of these lobsters of 7.4-9.3 km/day. While there is little doubt that the animals migrate great distances, the unknown parameter is what triggers the initial response.
Hence, we hypothesize that there is an annual migration of lobsters that is triggered by oceanographic events. The two-fold objective of this study is to better understand 1) the frequency and degree of thermal regime shifts in the Gulf of Maine/Georges Bank region and 2) what effect these shifts may have on the migratory lobster populations in that area.
The multiple scales of variability in both time and space necessitate
a multi-year data set to make conclusive arguments. Given
the relatively minor expense of the monitoring equipment relative to traditional
oceanographic moorings, a multi-year deployment is feasible. The intent
of this project however, is to simply introduce lobstermen to the probe
technology so that over the course of a few years they become familiar
with using the probes and comfortable with the operation. In years subsequent
to the funded period, it is anticipated that some fishermen will continue
to use probes, buy new probes, and contribute to an ongoing data pool.
Ever since the onset of this project, the eMOLT results have been posted at emolt.html under a section called "Results from the field". On entering this site, users are presented with a map of the Gulf of Maine. By clicking on small blue dots representing approximate deployment sites, links to a set of plots are listed. The user can then view either detailed plots of actual time series or filtered summary plots of the temperature time series for that particular site. In the case of the summary plots, a climatological seasonal cycle and its standard deviation (based of past NOAA-collected CTD data) is plotted as a background reference. In this way, users can immediate tell how current temperature relates to historical conditions. Examples of this summary plot for one two offshore lobstermen is presented in Figures 3a and 3b. At these sites, for example, the observed temperature was warmer than normal at the beginning of the year but colder than normal during the later part of the year. These particular lobstermen wonder now if this unusually cold water might partly explain their drastic reduction in catch in recent months. While catch data is available for all these sites on a near-weekly basis, they are, of course, not presented on publicly available web sites. Plots of catch records are made for individual lobstermen and the data is discussed privately off-line.
Calibration and comparison of the various probes was conducted in a
series of four control experiments in the past year. Multiple probes
from various manufacturers (VEMCO, ONSET, YSI, and SEABIRD) were deployed
together either in a tank at the NEFSC Aquarium or off the dock in Woods
Hole Harbor in order to validate the relative response of all the thermistors.
The results of these test with complete details and plots are posted on
web site. Biases between probes were often more than twice the value
specified by the manufacturer. As a consequence of this result,
we contracted the ONSET corporation to engineer a probe specifically for
our needs. The new probe designed specifically for eMOLT applications,
delivered in March 2001, has a temperature range of 0-20 degC and a 0.09
degC accuracy. Since the variability of interest are often
less than 1 degC, it is essential that eMOLT continue to carefully monitor
the performance of these probes. As part of our routine procedure
with each allotment of new probes and again at the end of each sampling
season, probes will be gathered, deployed together in controled environments,
and tested for biases and sensor drift.
As noted above, the primary objective of eMOLT is to document the spatial and temporal variability of water mass properties off the coast of New England. By monitoring the temperature and salinity at dozens of fixed sites around the Gulf of Maine region, we hope to quantify the scales of variability. One of the long-term scientific goals is to distinguish between advective and locally driven events that influence the bottom water conditions. Given multiple time series along the coast and within different basins, we expect to track the influx and transport of remote source waters. In subsequent years, with enough empirical information, one may build confidence in predictive models. While we envision a time in the future when eMOLT data will be used by local numerical modellers to both initialize and validate their simulations, our initial goal is to prove the concept: lobstermen can collect consistent and accurate data.
In addition to the physical oceanographic perspective, eMOLT
also provides important environmental information to New England lobstermen.
Do changes in bottom water temperature and salinity explain the migration
patterns and activity of Homarus americanus? Our hypothesis
regarding this aspect of eMOLT has evolved slightly from its initial form.
In Phase I we were interested in "weekly-to-monthly events" but, after
a year experience, we have shifted the Phase II time scale of interest
to a longer "seasonal-to-interannual" viewpoint. As depicted
in figures 3a and 3b, there are several episodic events over the course
of the year but the dominant feature in this series is the longer trend.
After further investigation of historical temperature records (Figure 1),
it has become clear that the interannual and even decadal changes
in temperature may be the more significant influence on lobster populations.
While episodic events may certainly be important in understanding the displacements
and redistribution of lobster abundance, the coverage of data necessary
to resolve these smaller scale phenomenon would be cost prohibitive.
We are now committed to maintaining the eMOLT sampling and have consequently
adjusted the focus of our investigation to both longer time scales and
a larger region.
The Atlantic Offshore Lobster Association, however, will conduct an independent eMOLT operation with their own budget and strategy. Since practical issues and scientific questions associated with the offshore fishery are often unrelated to those in the shallower waters, AOLA will coordinate their own involvement with eMOLT and will be funded for their effort. The eMOLT protocol for the offshore boats is necessarily different and does not apply to inshore fleet. Despite the independent operation however, the environmental data series will all be stored in a common eMOLT database and will be available to all participants.
The Brookhaven National Lab will provide the equipment and expertise to conduct the sampling. Individuals from the BNL Physical Oceanography Department, under the direction of Dr. C. Flagg, will refurbish and calibrate their existing set of YSI6000 (or will fund the YSI to do so).
The training will be accomplished during scheduled sessions prior to association meetings and/or fishermen forums at various New England locations. Training will be absolutely required for each individual that may be responsible for the handling the instrumentation. Participants will be taught to take water samples, upload data, email data, change batteries, clean cells, and setup electronics for subsequent deployments. Trained participants will be outfitted with salinity recording units, the appropriate software, battery supplies, and a download cable. The trainers will be paid personnel (see budget) and will be tasked specifically with a) training the participants and b) conducting the instrument calibration exercises.
The quality control of the data is conducted in three phases. First, the instrumentation are thoughoughly tested both prior to and after each season to determine any offsets/bias of the sensors (the conductivity cell in particular). These multi-probe experiments are conducted under controled conditions and the results are reported. A series of five multi-probe test deployments, for example, were conducted in Phase I of eMOLT. Even more testing and care of the sensors will need to be done in the case of salinity (Taylor, 1992). Second, calibration of the instruments will be conducted with water sampling at least once per year. To supplement these samples all other projects conducting CTD samples in the study area will be notified of eMOLT locations and asked to conduct cast in those locations. The NMFS and the ECOHAB surveys are two sources of potential calibrative sampling. It will be mutually beneficial to all projects to collaborate in this effort to obtain the maximum amount of sample overlaps. Finally, the data will be quality controlled in a post-processing mode after it is loaded into the ORACLE database.
The database management will be conducted by Jim Manning using ORACLE and web based forms. The data structures have already been developed but will undoubtedly evolve as the project progresses. There are currently four separate ORACLE "tables" setup to house the various levels of information. The first table, for example, stores all the information about the participants (email, home port, etc). The second table stores the information about the fixed sites (id, nominal lat/lon, depth). This later table includes the set of "historical" sites such as Boothbay, Woods Hole, and the Mass DMF sites. The other two tables include information about particular deployments and the data collected on those deployments. Since this is a relational database, each of the four tables have "key" variables in order to link to each other. The AOLA tables of site and set are independent from others but have the same basic structure.
The protocol to be followed by the actual participants has been developed over several years. It is fully documented in a web served "getting started manual" with various details on setting up the probe, where to deploy the probe, documenting the deployment, downloading the data, and emailing the data. The protocol has been designed to minimize the effort on the part of the lobstermen but, at the same time, to obtain accurate and consistently useful forms of data. In many of these steps there are multiple options to the protocol. In "documenting the deployment", for example, there are three methods to enter data. 1) Lobstermen using the Thistle Marine electronic logger do NOT have to maintain a spreadsheet documentation of their hauls. We have developed a protocol for merging the eMOLT/Thistle datasets which is transparent to the user. Most of the data that was formally recorded with method 2) on a spreadsheet with several columns (Serial number, Consecutive Probe setting, Consecutive site/haul code, Lat, Lon, time (in&out), Seasurface temp (in&out), Water depth, Number of pots, total pound kept, total pounds of shorts, are total pounds of eggers) are now recorded electronically. These records are then transferred electronically to NEFSC to be merged with the eMOLT database. The final method 3), currently under development, involves entering data on a web-served ORACLE form which gets automatically loaded into the appropriate database without human intervention. All eMOLT participants are required to attend at least an hour training session each year. As noted above, these training sessions will be offered on a quarterly basis and will likely be scheduled on the same day as the association meetings.
Probes are deployed to maximize the following parameters: length
of deployment at fixed sites, depth of deployment, distance between deployments,
and likelihood of returning to the site in subsequent years.
The first parameter , "length of deployment", is probably the most difficult criteria for lobstermen to follow since they often move their gear. Despite this restriction, we have found that some lobstermen do maintain some fixed sites for months at a time (see figures 3 above). All interested participants have been informed of this limitation and are encouraged to comply with it as much as possible. In the end, we expect to have some fixed sites, especially in the coastal waters of Maine, that may have less than a month of data from a particular location but that these exact sites will be revisited in subsequent years.
As a government agency, the NEFSC is mandated to collect, process, and serve information associated with local fisheries. As an oceanographer employed by that agency for the past 14 years, Jim Manning , while primarily occupied for the last decade with the Georges Bank GLOBEC project, is now responsible for managing NEFSC datasets associated with the physical water mass conditions. He is now tasked with developing an integrated operational oceanographic system. With help from a few others at the Woods Hole Lab, the physical oceanographic sampling on research cruises by NOAA vessels (including observations with Conductivity, Temperature and Depth recorders, the Acoustic Doppler Current Meter (ADCP), and various other shipboard sensors) are processed, analyzed, and web-served. An effort is underway to load all of these on-going data collections together with historical archives into the same ORACLE database. The computing power and support is provided by the NEFSC Data Management Systems. While maintaining both hardware and software for the entire center, DMS continually integrates the newest technological advances. The latest developments include an upgrade to ORACLE 8i which has more internet-serving capabilities.
As a former employee for the Massachusetts Division of Marine Fisheries, David McCarron (now with GoMLF) has extensive experience with large ORACLE databases. His primary task at DMF for XX years was to provide ORACLE/SQL programming assistance. He has worked with Manning in designing and implementing the eMOLT data structure during eMOLT Phase I. Now, as director of the GoMLF, David has very close contact with the lobster industry. His primary task now is to maintain communications between the various lobster associations and ensure that projects like eMOLT are merged with related efforts around the entire Gulf of Maine Region.
Dr. C. Flagg, now at the Brookhaven National Laboratory, has been involved with nearly every large-scale physical oceanographic investigation of New Englands coastal waters since the mid-1970's. As lead oceanographer on several projects in the past three decades, he has written extensively and especially on physical water mass properties. He joins our effort as an expert on collecting, processing, and archiving physical oceanographic data. As an example of that effort, he has compiled and posted the entire collection of ADCP data from GLOBEC cruises. Along with Manning, he is actively involved with integrating observations with numerical circulation models in an effort to provide hindcast simulations.
Finally, Bonnie Spinazzola, the executive director of the Atlantic Offshore
Association, has been involved with all aspects of fisheries for
over a decade. Well aware of the needs and concerns of the
lobster industry, she represents dozens of individuals. She
is involved with research efforts other than eMOLT and is committed
to integrating projects on order to maximize the benefit for her constituents.
All eMOLT participants will contribute to the same centralized database regardless of association or project affiliation. Many of the AOLA/eMOLT participants may be involved in other projects (such as the "Automated Monitoring of Offshore Lobster Fishery") and many of the MLA/eMOLT participants may be involved with in other projects (such as the "Ventless Traps Survey"), but the environmental monitoring information will be stored in a common archive. The lobster catch information will NOT be shared between projects or individuals. The data will be served by users entering information on a web-served ORACLE form. Specific criteria such as time or position (lat/lon) will be used to extract user-selected portion of the time series. Prepared plots as well as user-requested plots has been and will be generated with a combination of ORACLE, perl, and MATLAB programming.
Individual lobstermen will have the opportunity to meet with eMOLT representatives
on a quarterly basis at their respective association meetings.
As participants, they are required to do so on at least an annual basis
for training purposes. Individual lobstermen will meet with Jim Manning
at least once per year (either at the annual forums/weekends or
some other prearranged locations) to discussed catch data and review results.
Annual reports for each lobstermen will be prepared for this meeting in
Unlike the first phase of eMOLT, individual lobstermen will be directly reimbursed for their efforts (~$2k/each, see budget). Given that salinity probes are larger and more delicate than the temperature probes, they require more care and maintenance. Individuals that deploy these units will need to spend significant time to be properly trained. A limited number of individuals (<12) will be paid for their first successful deployments. It will be understood that this is a one-time payment to selected individuals awarded for their pioneering effort to develop the system protocol. These individuals (like Palombo, Colbert, and Cote of the AOLA in the case of the temperature probe methodology) will be selected by each association as leaders in the industry's drive towards technological improvements. Subsequent routine deployments in later years will be unpaid.
Dr C. Flagg (Brookhaven National Lab) will be funded ($4k, see budget) for insurance coverage of the borrowed instrumentation. It is understood a) that the instruments belong to BNL , b) that if two of the YSI units are lost at sea, the remaining six will be immediately returned to BNL immediately, and c) that their funding will be provided for both the trouble of packaging them up and, more importantly, in case there is significant loss of the instrumentation.
Thistle Marine is reimbursed for the database support. They are contracted ($2.5k) to extract the data sent by eMOLT participants to NEFSC in emailed files with specified formats.
Jim Manning (NEFSC) whose salary is covered by NOAA/NMFS will be funded (~$2k) for travel to annual association meetings and fishermen forums and miscellaneous office expenses.
Each of the four lobster associations (AOLA, Mass, Maine, and Downeast)
as well as the GoMLF will be funded $5k for salary support and office
expenses. Much of this support is for training the lobstermen to
intialize/care for instrumentation, collect data, and, most important,
to document their deployments.
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