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A series of monitoring or empirical studies either have been completed or are ongoing. The NMFS continues to monitor Tortugas pink shrimp harvest and develop the simulation model and has completed pink shrimp salinity/temperature tolerance experiments. USGS is continuing to monitor pink shrimp distribution and abundance in relation to environmental conditions and habitat in Florida Bay and to measure water flow in order to estimate postlarval transport within the Bay. With UM a critical collaborative study to identify and quantify the seasonality and magnitude of pathways of postlarval immigration to Florida Bay is continuing. Statistical studies of these and other data are ongoing relating pink shrimp to salinity, temperature and habitat in Florida Bay.
The pink shrimp is a good indicator of the health and productivity of the Bay. The effect of salinity and temperature on pink shrimp growth and survivorship and of habitat on juvenile density provide a basis for predicting the abundance of pink shrimp juveniles in Florida Bay and thus the magnitude of recruitment to the Tortugas fishery. A landscape model is needed to express pink shrimp performance measures as functions of spatially complex factors acting across the Bay. Florida Bay is a complex shallow water ecosystem with distinct zones of different physical and biological characteristics (Fourqurean and Robblee 1999) that differ in their potential to support pink shrimp. The influence of upstream water management on pink shrimp recruitment from Florida Bay is expected to express itself principally through changes in salinity and seagrass habitat associated with changes in freshwater inflow. Predictions of the effect of these changes on the Bay’s productive capacity require consideration not only of the resulting salinity and seagrass changes but also the resulting change in the area of overlap of these factors favorable to the pink shrimp (Browder and Moore 1981; Browder 1991). Critical long-term databases exist for pink shrimp that are suitable for developing empirical relationships and baselines.
U.S. Department of Agriculture - Natural Resources Conservation Service (NRCS) Department of the Interior - U.S. Geological Survey Department of Commerce - National Oceanic and Atmospheric Administration (NOAA) Environmental Protection Agency (EPA) Smithsonian Institution - National Museum of Natural History (NMNH)
40001 State Road 9336
Patino, Eduardo; Zucker, Mark
Boulger, Jr, R. W.; Oblinger, C. J.; Smith, B. A.
accessed as of 5/25/2011
Morlock, S. E.; Caldwell, W. S.
accessed as of 5/23/2011
Simpson, M. R.
available online only; accessed as of 5/23/2011
Robblee, M. B.
The full text is available as a free download
Restrepo, V. R.; Rice, J. K.; Robblee, M. B.; Zein-Eldin, A.
Nguyen, H. T.; Ross, J. H.
Analysis of this data set will provide the pink shrimp simulation model with seasonal timing, size frequency data as well as abundance and size of juvenile pink shrimp in relation to bank, basin and near-key habitats seagrass cover. Specific objectives include:
1. Quantify density and size of juvenile pink shrimp in relation to bank, basin and near-key habitat in Johnson Key Basin, western Florida Bay. 2. Implement Braun Blanquet cover estimation as a means of associating pink shrimp abundance to seagrass and algal habitat. 3. Evaluate the existing benthic database in order to develop a monitoring protocol for assessing juvenile pink shrimp abundance and distribution in Florida Bay in relation to changes in salinity.
Using established methods nine stations (3 bank, 3 basin, 3 near-key habitat) in Johnson Key Basin will be sampled on a six-week interval for a total of 9 collections during FY2003. A one m2 throw-trap is used to quantitatively collect seagrass associated fish and invertebrates including the pink shrimp. Each throw-trap is swept three times to remove organisms. Four throw-trap samples are collected at each station as well as a suite of environmental and habitat variables. Previously habitat estimates have been made based on biomass estimates of seagrass and algae associated with throw-trap collections. Braun Blanquet is a categorical cover estimate technique currently used in seagrass monitoring programs in Florida Bay and the Florida Keys. In the laboratory samples will be sorted, all fish and shrimp (caridean and pink shrimp) will be identified to species and enumerated. Data will be stored in the Everglades National Park Oracle Database.
40001 State Road 9336
1. Quantify the seasonality and magnitude of postlarval pink shrimp immigration to Florida Bay. 2. Compare timing and magnitude of postlarval pink shrimp immigration from the Gulf of Mexico and the Atlantic Ocean. 3. Assess accessibility of inner Florida Bay to postlarval pink shrimp by comparing the timing and magnitude of Gulf of Mexico stations to Conchie Channel; of Atlantic Ocean stations to Panhandle Key Cut. 4. Assess sampling protocols by comparing postlarvae catch in relation to tidal phase and depth. 5. Participate in the development of a transport module for the pink shrimp simulation model.
Post larval pink shrimp sampling was initiated in January 2000. Channel nets (0.75 m2 opening, 1-mm mesh net, 500-micron mesh in the cod end) are used. The nets are attached to fixed moorings in the evening and samples are collected the following morning having passively collected postlarvae over night. The top of the channel net is set at .5 meter deep. At present paired channel nets sample six channels on two nights of the new moon; thus, four samples are obtained from each site each month for a total of 24. Pink shrimp postlarvae are sorted from the sample, identified, and preserved in 95% ethanol. The raw catch in each sample is standardized to density per 1,000 m3 of water filtered. Mean monthly density is calculated as the average over the two sampling nights. Densities are tested for normality and homogeneity of variance. Two experiments will be conducted to evaluate the current sampling methods. The present method of drifting the channel nets over night will be evaluated by sampling on a two-hour interval with the object of understanding when post larvae are most abundant. A second experiment will evaluate the relationship of depth and postlarval pink shrimp abundance by comparing catch in nets drifted at the surface, .5 meter and 1 meter. Experimental results will be used to aid in interpretation of catches or alternatively to modify sampling protocols.
40001 State Road 9336
1. Estimate volume transport in the six channels being sampled for postlarvae. 2. Construct rating curves at each station under a variety of tidal flow conditions in order to improve volume transport estimates. 3. Compare volume transport among the six stations in a comparison of postlarval immigration into Florida Bay. 4. Participate in the development of a transport module for the pink shrimp simulation model.
Measurements of flow, stage, and salinity will continue in FY 2003 in the six channels being sampled for post larvae. In collaboration with Dr. Joan Browder of NOAA these data will be applied to the construction of the larval transport module for the pink shrimp simulation module. Methods developed to date and in other studies will continue to be employed. Acoustic Doppler Velocity Meters (ADVM) have been installed at the instrumented sites and are used to measure continuous (15- minute) water velocity. A boat-mounted Acoustic Doppler Current Profiler (ADCP) is used to calculate total discharge along a transect of the channels during inspections. The ADCP also measures water depth, boat speed, and direction of boat movement using acoustic reflections from the streambed. Discharge and flow direction are both calculated from data collected with the ADCP. The mean velocity for the creek section is calculated by dividing the total discharge measured with the ADCP by the cross-sectional area corresponding to the water level at the time of the discharge measurement. The cross-sectional area is computed by using site-specific stage-area ratings. A velocity rating between the mean ADCP velocity and the in situ ADVM velocity is calculated by regression analysis. This rating equation is then used to calculate continous discharge using the velocity data. Stage measurements are made acoustically and through water pressure in the ADVM and Salinity instrumentation respectively. Stage is used to define the cross-sectional area over which flow measurements are made, and are used in the regression analysis between flow and stage. Salinity measured near the surface and bottom of each channel to quantify the vertical stratification present at each site, which could be detrimental to acoustic signals. Additionally, temperature is measured to monitor possible vertical temperature gradients that could be detrimental to acoustic signals and as a necessary parameter to calculate salinity from conductivity.
Field data collection of water level, temperature, salinity, and discharge: Data collected at instrumented sites included continuous (15-minute or hourly) measurements of water level, water velocity, salinity/specific conductance, temperature, and periodic measurements of discharge for index velocity calibrations. More information on index velocity techniques is discussed in Hittle and others (2001) and Morlock and others (2002), and Ruhl and others (2005). Non-transmitting sites are routinely serviced and field data is manually uploaded to the USGS database.
Boat mounted acoustic Doppler current profilers (ADCP) were used to measure discharge at the estuarine monitoring stations. The ADCP uses the Doppler shift in returned acoustic signals reflected by particles suspended in the water to determine the velocity of moving water (Simpson 2002 and Oberg and others 2005). The ADCP also has the capability to measure water depth, flow direction, and speed of the boat based on acoustic reflections from the streambed. Discharge and flow direction were both calculated from information provided by the ADCP and computer software. The mean water velocity was calculated by dividing the total measured discharge by the cross-sectional area corresponding to the water level at the time of measurement (Sauer 2002 and Ruhl and others 2005). Acoustic velocity meter (AVM) and acoustic Doppler velocity meter (ADVM) systems were used to measure continuous water velocity. The velocity measured by the ADVM systems represents an "index" of the mean water velocity. The index velocity is a measured velocity at the instrumented sites that can be used to compute the mean channel velocity.
A boat-mounted Acoustic Doppler Current Profiler (ADCP) was used to calculate total discharge along a transect of the channels during inspections. The ADCP also measured water depth, boat speed, and direction of boat movement using acoustic reflections from the streambed. Discharge and flow direction were both calculated from data collected with the ADCP. The mean velocity for the creek section was calculated by dividing the total discharge measured with the ADCP by the cross-sectional area corresponding to the water level at the time of the discharge measurement. The cross-sectional area was computed by using site-specific stage-area ratings. A velocity rating between the mean ADCP velocity and the in situ ADVM velocity was calculated by regression analysis. This rating equation was then used to calculate continous discharge using the velocity data. Water level data were used to determine water depth and to calculate the stage-dependent cross-sectional area. Water level data were collected an incremental shaft encoder equipped with a pulley, stainless-steel tape, weight, and float inside an 8 in. polyvinyl chloride pipe stilling well (Sauer 2002), pressure sensors, or acoustic transducers. Corrections to water level data followed USGS quality assurance quality control protocols (Rantz and others 1982 and Sauer 2002).
Salinity was measured near mid-depth help determine the presence of freshwater flow and to examine potential effects on the acoustic signals caused by salinity stratification. Continuous salinity measurements are important for describing the seasonal patterns of freshwater flow (wet/dry season) and for identifying bi-directional flow. Elevations of the continuous monitors are available upon request. Temperature was measured to monitor possible vertical gradients that also could affect acoustic signals. Due to biological fouling and electronic drift, the continuous monitor requires routine cleaning and calibration to maintain data quality. During the period of record, continuous monitors were calibrated during site visits to ambient conditions using a reference probe (USGS National Field Manual). Ambient salinity conditions were measured with a portable reference probe that was calibrated and or verified against a range of laboratory specific conductance standards. Reference temperature probes are verified against a NIST thermometer prior to field trips. When in situ temperature measurements differed by more than 0.2 deg. C when compared to the reference temperature probe, the in situ probe was replaced.
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