Project Work Plan

Greater Everglades Science Program: Place-Based Studies

Project Work Plan FY 2003

A. GENERAL INFORMATION:

Project Title: Empirical Studies In Support Of A Pink Shrimp, Farfantepenaeus Duorarum, Simulation Model For Florida Bay
Project start date: October 1999 Project end date: September 2004
Principal Investigator: Michael B. Robblee
Email address: mike_robblee@usgs.gov
Phone: (305) 242-7832 Fax: (305) 242-7832
Mail address: c/o South Florida Natural Resources Center, Everglades National Park, 40001 State Road 9336, Homestead, FL 33034

Other Investigator(s): Clinton Hittle
Email address: cdhittle@usgs.gov
Phone: 305-717-5815 Fax: 305-717-5801
Mail address: 9100 NW 36^th St. #107 Miami, FL 33178

Project Summary: Florida Bay lies downstream of the Everglades ecosystem. Perceived deterioration of the Everglades over the last century - and Florida Bay since the mid-1980's - is generally viewed as linked to changes in freshwater flow and water quality associated with water management in South Florida. Concern for the decline of South Florida's natural systems has led to the development of the Federal and State Comprehensive Everglades Restoration Plan (CERP). CERP is a science-based restoration plan based on the concept of adaptive assessment, in which models and performance measures of ecological function are used iteratively to design projects, to monitor the effects of their implementation and, when need is indicated, to recommend design refinements.

A pink shrimp simulation model has been identified as a priority need in CERP by the South Florida Water Management District, NOAA, NPS and USGS. This model has been under development by a team of USGS, NOAA and University of Miami researchers since 1999. To date this project has been funded by NOAA's Coastal Oceans Program, DOI's Critical Ecosystem Studies Initiative and by USGS base funds. The purpose of the model is to assist in designing and refining restoration alternatives by predicting their impact on production of pink shrimp in Florida Bay and on shrimp recruitment from Florida Bay to the Tortugas fishery.

Focus on the pink shrimp is based on the following rationale.

1. The pink shrimp is a good indicator of the health and productivity of the Bay. Pink shrimp in South Florida spawn offshore near the Dry Tortugas about 150 km from Florida Bay. Larval stages develop offshore and postlarvae immigrate to Florida Bay, where juveniles settle for several months of feeding and growth before recruiting to the Tortugas fishery (Costello and Allen 1966). The pink shrimp is economically important because it supports the multi-million-dollar Tortugas fishery (Upton et al. 1992). Statistical relationships have been found between shrimp fishery catch rates and indices of freshwater inflow to Florida Bay and connected coastal embayments (Browder 1985, Sheridan 1996).
2. 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. The generally recognized response of macroinvertebrates to temperature and salinity (Kinne 1971), and the wide range of temperature (~12 °C to 45°C) and salinity (0 ‰ to 70 ‰) (Robblee et al. 2001) found within Florida Bay, suggest that these environmental variables will substantially influence pink shrimp abundance, growth and distribution in the Bay. Juvenile pink shrimp in Florida Bay are strongly linked to seagrass habitat (Costello et al. 1986). Studies by Sheridan (1992) and Robblee and DiDomenico (1991) document the influence of changes in benthic vegetation due to seagrass die-off on juvenile shrimp densities in the Bay.
3. 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).
4. Critical long-term databases exist for pink shrimp that are suitable for developing empirical relationships and baselines. NOAA has collected and maintained catch and effort data on this fishery since 1960. The National Park Service and USGS have monitored juvenile shrimp abundance in relation to physical conditions of salinity and temperature and seagrass habitat, principally in western Florida Bay, since 1981 (Robblee et al. 1991).

The full concept of the model under development is shown in Figure 1. The modeling approach used emphasizes growth and survival in relation to salinity and temperature in the inshore Florida Bay nursery. Salinity was chosen because the influence of upstream water management is expected to express itself through changes in salinity associated with change in freshwater inflow to the bay and because sensitivity to salinity variation has been demonstrated in invertebrates (Kinne, 1971). Temperature was included because it affects growth and survival, varies spatially in the bay, and there can be salinity and temperature interactions (Dall et al. 1990). At present running the model using salinity and temperature data from different regions of the bay captures the landscape of Florida Bay. A dynamic landscape is being developed because other conditions, varying spatially in Florida Bay, may have to be favorable to pink shrimp in order that salinity affects growth and survival (Browder and Moore 1981, Browder 1991). Critical empirical information needs include:

1. abundance and size of juvenile pink shrimp in Florida Bay among bank, basin and near-key habitats, in relation to seagrass cover and in different regions of the bay;
2. information on the seasonal timing, abundance and distribution (thru the Florida Keys vs the Gulf of Mexico) of postlarval pink shrimp immigrating to Florida Bay;
3. information on the timing, abundance and size of juvenile pink shrimp emigrating from Florida Bay to recruit to the fishery;
4. physical data on patterns of water flow for transport of postlarval and juvenile pink shrimp in the bay.

Figure 1 Diagram of the pink shrimp simulation model.
[larger version]

Project Objectives and Strategy: A calibrated and verified model is the goal of this project as well as this project's chief organizing element. The process of developing the model has identified critical information needs for the model that, depending on priority, have become project objectives for empirical research. Current objectives include:

1. Quantify seasonal patterns in postlarval abundance and evaluate pathways of postlarval pink shrimp immigration to Florida Bay.
2. Quantify the distribution of juvenile pink shrimp in Florida Bay in relation to bank and basin habitats and seagrass cover.
3. Evaluate the relative accessibility of regions of Florida Bay to postlarval pink shrimp.
4. Quantify the seasonality and size of juvenile pink shrimp emigrating from Florida Bay.

Potential Impacts and Major Products: When completed the model will serve as an assessment tool in CERP for use by management to evaluate the effects of proposed water management alternatives. The empirical data collected will be central in continuing the development of a pink shrimp performance measure for Florida Bay and establishing appropriate restoration targets for the pink shrimp in various regions in the bay. The long-term juvenile pink shrimp data set will serve as baseline conditions from which to assess restoration and as the basis for designing a monitoring protocol for the pink shrimp in Florida Bay for CERP. The continuous flow data at six sites in the bay will extremely useful for the development of a hydrodynamic model for Florida Bay. Major products include:

1. A landscape-based simulation model of the pink shrimp for Florida Bay.
2. A pink shrimp performance measure for Florida Bay and targets for various regions of the bay.
3. An extension of the existing juvenile pink shrimp database in Johnson Key Basin. This is the longest (almost 20 yrs) and most continuous benthic biological record available for Florida Bay.
4. A two-year continuous record of water velocity, volume transport, salinity, temperature and depth at four sites on the outer boundary of Florida Bay and at two interior sites.
5. A comparison of juvenile pink shrimp in Johnson Key Basin, western Florida Bay in relation to the timing and magnitude of immigrating postlarval shrimp through the two principal pathways where by postlarval pink shrimp enter Florida Bay.

Collaborators:

Dr. Joan A. Browder
National Marine Fisheries Service
Southeast Fisheries Science Center
75 Virginia Beach Drive
Miami, FL 33149
305-361-4270
joan.browder@noaa.gov

Dr. Maria M. Criales
University of Miami
Rosentiel School of Marine and Atmospheric Sciences
4600 Rickenbacker Causeway
Miami, FL 33149
305-361-4073
mcriales@rsmas.miami.edu

Clients:

• Central Everglades Restoration Program
• National Marine Fisheries Service
• National Park Service

Literature Cited:

Browder, J. A. 1985. Relationship between pink shrimp production on the Tortugas grounds and water flow patterns in the Florida Everglades. Bulletin of Marine Science 37:839-856.

Browder, J. A. and D. Moore. 1981. A new approach to determining the quantitative relationship between fishery production and the flow of fresh water to estuaries. Pages 403-430 in R. Cross and D. Williams (eds.). Proceedings, National Symposium on Freshwater Inflow to Estuaries, Vol.1. FWS/OBS-81/04. U.S. Fish and Wildlife Service, Washington, DC.

Browder, J.A. 1991. Watershed management and the importance of freshwater flow to estuaries. Pages 7-22 in S.F. Treat and P.A. Clark (eds.), Proceedings, Tampa Bay Area Scientific Information Symposium 2. 27 February-1 March 1991; Tampa, Florida, 528 pp.

Browder, J. A., V. R. Restrepo, J. K. Rice, M. B. Robblee, and Z. Zein-Eldin. 1999. Environmental influences on potential recruitment of pink shrimp, Farfantepenaeus duorarum, from Florida Bay nursery grounds. Estuaries 22:484-499.

Browder, J. A., Z. Zein-Eldin, M. Criales, M. B. Robblee, S. Wong, and T. L. Jackson. 2001a. Dynamics of pink shrimp recruitment potential in relation to freshwater inflow. Invited oral presentation at the 16th Biennial Conference of the Estuarine Research Federation. 4-8 November 2001, St. Petersburg Beach, FL.

Browder, J. A., T. L. Jackson, M. M. Criales and M. B. Robblee. 2001b. Immigration pathways of pink shrimp postlarvae into Florida Bay. In: Proceedings 2001 Florida Bay Science Conference, Key Largo, Florida, April 23-26, 2001, p 34-36.

Costello, T. J., D. M. Allen, and H. Hudson. 1986. Distribution, seasonal abundance, and ecology of juvenile northern pink shrimp, Penaeus duorarum, in the Florida Bay area. NOAA Tech. Memo. NMFS-SEFC (161):83 p.

Costello, T. J. and D. M. Allen. 1966. Migrations and geographic distribution of pink shrimp, Penaeus duorarum, of the Tortugas and Sanibel Grounds, Florida. U. S. Fish and Wildl. Serv., Fish. Bull. 65: 449-459.

Enos, P. and R. D. Perkins. 1979. Evolution of Florida Bay from island stratigraphy. Geol. Soc. Am. Bull. 90: 59-83.

Fourqurean, J. W, and M. B. Robblee. 1999. Florida Bay: a history of recent ecological changes. Estuaries. 22(2B): 345-357.

Kinne, O. 1971. Invertebrates. Pages 821-995 In: H. Barnes (ed.), Marine Ecology, Vol. 1, Part 2. Wiley-Interscience, New York.

Robblee, M. B. and W. J. DiDomenico. 1991. Seagrass die-off threatens ecology of Florida Bay. Park Science 11:21-22.

Robblee, M., S.D. Jewell and T.W. Schmidt. 1991. Temporal and spatial variation in the pink shrimp, Penaeus duorarum, in Florida Bay and adjacent waters of Everglades National Park. Annual Report, South Florida Research Center, Everglades National Park, Homestead, FL. 29 pp.

Robblee, M.B., G. Clement, D. Smith and R. Halley. 2001 Salinity Pattern in Florida Bay: A synthesis (1900-2000). In: Proceedings 2001 Florida Bay Science Conference, Key Largo, Florida, April 23-26, 2001, p 34-36.

Sheridan, P. F. 1992. Comparative habitat utilization by estuarine macrofauna within the mangrove ecosystem of Rookery Bay, Florida. Bull. Mar. Sci. 50:21-39.

Sheridan, P.F. 1996. Forecasting the fishery for pink shrimp, Penaeus duorarum, on the Tortugas grounds, Florida. Fish. Bull. 94:743-755.

Upton, H. F., P. Hoar, and M. Upton. 1992. The Gulf of Mexico Shrimp Fishery: Profile of a Valuable National Resource. Center for Marine Conservation, Washington, D.C.

B. WORK PLAN

Title of Task 1: Quantifying juvenile pink shrimp abundance in Florida Bay
Task Leaders: Michael Robblee
Phone: 305-242-7832
Fax: 305-242-7855
Task Status (proposed or active): ACTIVE
Task priority: HIGH
Task Personnel: Michael Robblee, Andre Daniels, Vin DiFrenna, Joel Conlin, George Gallegos

Task Summary and Objectives: This task extends a long-term juvenile pink shrimp data set from Johnson Key Basin, western Florida Bay. Critical restoration questions in Florida Bay involve linking salinity and upstream water management with the ecological function of the bay for the purposes of evaluating proposed management alternatives and for assessing the effect of their implementation. This database is ideal for these purposes because it: 1) quantitatively tracks juvenile pink abundance and size in western Florida Bay, 2) links pink shrimp abundance to environmental conditions, macrohabitat (bank, basin, near-key) and micro-habitat (seagrass and algal cover) and, 3) extends a long-term, 1984 to present with gaps, baseline data set against which patterns of pink shrimp abundance can be judged in relation to change. 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.

Work to be undertaken during the proposal year and a description of the methods and procedures: Using established methods (Robblee et al 1991) 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 estimatews 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.

Planned Outreach: USGS Fact Sheet will be developed for the long-term data set. Using these data in collaboration with Dr. Joan Browder of NOAA the development of a pinks shrimp performance measure and appropriate restoration targets will be continued for CERP. Project results will be present at the Annual Florida Bay Science Conference and at a scientific meeting.

Title of Task 2: Quantifying postlarval pink shrimp immigration to Florida Bay
Task Leaders: Michael Robblee
Phone: 305-242-7832
Fax: 305-242-7832
Task Status (proposed or active): ACTIVE
Task priority: HIGH
Task Personnel: Michael Robblee, Joan Browder, Maria Criales, Tom Jackson, Andre Daniels, Vin DiFrenna, Joel Conlin, George Gallegos

Task Summary and Objectives: The timing, distribution and magnitude of postlarval shrimp immigration to Florida Bay were identified as critical information needs required for development of the pink shrimp simulation model. To address these needs a field study is ongoing to estimate and compare monthly postlarval immigration to Florida Bay through six defined channels: two from the Gulf of Mexico (Sandy Key, Middle Ground) into western Florida Bay, two from the Atlantic Ocean (Whale Harbor Channel, Indian Key Channel) through the Florida Keys into southwestern and central Florida Bay, and two interior channels that connect Florida Bay sub basins, Conchie Channel near Flamingo in western Florida Bay and Panhandle Key Cut in south central Florida Bay. While this project to develop a pink shrimp simulation model is a joint effort involving a team of scientists this task is where this relationship is most clearly evident. Sampling postlarval pink shrimp at these six stations involves the closely coordinated efforts of NOAA, responsible for sampling the Florida Keys stations, and UM and USGS personnel with responsibility for sampling the western Florida Bay stations. Specific objectives include:

2. Quantify the seasonality and magnitude of postlarval pink shrimp immigration to Florida Bay.
3. Compare timing and magnitude of postlarval pink shrimp immigration from the Gulf of Mexico and The Atlantic Ocean
4. 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.
5. Assess sampling protocols by comparing postlarvae catch in relation to tidal phase and depth.
6. Participate in the development of a transport module for the pink shrimp simulation model.

Work to be undertaken during the proposal year and a description of the methods and procedures: Post larval pink shrimp sampling was initiated in January 2000. Channel nets (0.75 m² opening, 1-mm mesh net, 500-µ mesh in the cod end) are used. The nets are attached to fixed moorings. The nets are connected to the 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 were 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 was calculated as the average over the two sampling nights. Densities were tested for normality and homogeneity of variance. This sampling routine will be continued in FY2003. Two experiments will be conducted to evaluate our current sapling methods. Our 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.

Planned Outreach: USGS Fact Sheet will be developed for the long-term data set. Using these data in collaboration with Dr. Joan Browder of NOAA the development of a pinks shrimp performance measure and appropriate restoration targets will be continued for CERP. Project results will be present at the Annual Florida Bay Science Conference and at a scientific meeting.

Title of Task 3: Estimating volume transport continuously at postlarval pink shrimp stations
Task Leaders: Clinton Hittle
Phone: 305-717-5815
Fax: 305-717-5801
Task Status (proposed or active): ACTIVE
Task priority: HIGH
Task Personnel: Clinton Hittle, Grant Poole

Task Summary and Objectives: In October of 2001, a study began to determine the volume transport at each of the six stations where postlarvae are being sampled. Acoustic Doppler technology has been installed at the four defined channels connecting Florida Bay with the Gulf of Mexico (Sandy, Middle Ground) and the Atlantic Ocean (Whale Harbor, Indian Key) and the two interior channels (Conchie, Panhandle) that connect to Florida Bay interior sub basins where monthly postlarval sampling occurs. These estimates of volume transport facilitate the direct comparison of the six stations being sampled for postlarvae and are essential to an assessment of the relative importance of the two known pathways of larval immigration into Florida Bay - west from the Gulf of Mexico and from the Atlantic Ocean through passages in the Florida Keys. These continuous measurements are also essential in developing a larval transport module for the pink shrimp simulation model. A significant additional benefit of the data being collected is that it will be very useful in the development of a Florida Bay circulation model, a high priority of CERP. Specific objectives include:

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.

Work to be undertaken during the proposal year and a description of the methods and procedures: 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.

Planned Outreach: A USGS Fact Sheet will be developed describing this joint NOAA/USGS project. Task results will be presented at the Annual Florida Bay Science Conference. Continuous 15-minuted data of these physical parameters will be available on the USGS SOFIA web page.

Title of Task 4: Quantifying juvenile pink shrimp emigration from Florida Bay
Task Leaders: Michael Robblee
Phone: 305-242-7832
Fax: 305-242-7855
Task Status (proposed or active): PROPOSED
Task priority: HIGH
Task Personnel: Michael Robblee, Joan Browder, Maria Criales, Tom Jackson, Andre Daniels, Vin DiFrenna, Joel Conlin, George Gallegos

Task Summary and Objectives: Understanding the mechanisms, timing and distribution of juvenile and sub-adult pink shrimp emigration from Florida Bay is the least understood major process occurring in nursery habitats supporting the Tortugas fishery. Just as understanding the basic dynamics of immigration is critical to the pink shrimp simulation model the basic dynamics of emigration are critical. Anecdotal information associates pink shrimp "runs" with winter and early spring cold front passage. The assumption is that shrimp, able to sense water movement and direction, ride the strong water flows associated with frontal passage to leave the bay. It is proposed here to conductan exploratory study to modify existing channel nets to sample juvenile and sub-adult pink shrimp and to evaluated the timing distribution and magnitude of shrimp movements to leave Florida Bay. Specific objectives include:

1. Modify existing channel nets to passively sample juvenile and sub-adult pink shrimp and develop an effective sampling protocol.
2. Sample juvenile and sub-adult shrimp exiting Florida Bay during the winter at Conchie Channel.
3. Characterize pink shrimp emigration in relation to relevant physical, environmental and climate variables such as tide, wide, temperature, salinity, wind, etc.

Work to be undertaken during the proposal year and a description of the methods and procedures: In FY 2003 existing nets will be modified to sample juvenile and sub-adult shrimp and exploratory sampling will be conducted in Conchie channel near Flamingo. Currently postlarvae are sampled using channel nets (0.75 m² opening, 1-mm mesh net, 500-µ mesh in the cod end) are used. The nets are attached to fixed moorings. The nets are connected to the 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. Initially these nets will be modified to sample juvenile and sub-adult shrimp by increasing the mesh size to 3mm and adding a light source. Experiments will be conducted to evaluate the effect of presence/absence of a light source and depth on sampling characteristics. A mobile mooring system using Danforth boat anchors will be developed so that the modified channel nets can be easily moved to facilitate exploratory sampling. Pink shrimp will be sorted from the sample, identified, sized and preserved in 95% ethanol. The raw catch in each sample will be standardized to density per 1,000 m³ of water filtered. Between December and May three nets will be deployed on the new moon in conjunction with postlarval pink shrimp sampling. These collections will be supplemented with additional samples. First, the nets will be deployed on a series of randomly determined nights to compare catch with moon phase. Second, nets will be deployed during inclement weather associated with frontal passages to evaluate this transport mechanism. Physical and environmental variables, water velocity, volume transport, salinity, tide and temperature will be collected continuously when shrimp are being collected. Wind speed and direction data is available for Flamingo from Everglades National Park.

Planned Outreach: These results will be reported on at the Annual Florida Bay Science Conference.