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Development of an operational model for predicting the near real time distribution and abundance of the scyphomedusa, Chrysaora quinquecirrha, in the Chesapeake Bay(2005)

Project Description:
Development of an Operational Model for Predicting the Near-Real Time Distribution and Abundance of the Scyphomedusa, Chrysaora quinquecirrha, in Chesapeake Bay. This project is part of the CSCOR ecological forecasting program (EcoFore). Jellyfish blooms influence plankton dynamics in coastal waters worldwide. These blooms can reduce food available to higher trophic levels and fish, and they negatively impact tourism in the coastal eastern U.S.A., yet factors that affect bloom development and distribution are not well understood. The stinging Chrysaora quinquecirrha has the potential to control the flow of energy and nutrients through the food web due to its seasonally high abundance and consumption rates. The impact of Chrysaora on the Chesapeake ecosystem and fisheries might be better understood if their presence could be predicted. Chrysaora is an ideal target species for ecological forecasting because abundant distribution data have been collected over many years and the primary factors that control its occurrence can be predicted with models. Chrysaora abundance, temperature and salinity were collected from he Bay and its tributaries during 1987-2000, and these data were used to develop a model that describes the preferred habitat of the medusan form of Chrysaora. This emperically-derived model predicts the near-real time probability of Chrysaora encounter as a function of surface temperature and salinity. This method, currently operating in a demonstration mode) allows nowcasts to be generated in order to predict the distribution and likelihood of Chrysaora occurrence in Chesapeake Bay by identifying locations where conditions coincide with Chrysaora's preferred habitat. These nowcasts are staged on a website for the public.

Expected Outcome:
This proposal is a multi-investigator, multi-institutional effort which is developing a capability to operationally model nowcasts and forecasts of the abundance and distribution of a jellyfish species (Chrysaora quinquecirrha) in Chesapeake Bay. It is also furthering the understanding of the role that jellyfish play in the Chesapeake Bay ecosystem as predators and competitors of fish species. This goal will be accomplished by refining and validating an existing habitat model in order to more accurately forecast the distribution of Chrysaora in the Chesapeake Bay and to expand the use of nowcasting capability. In particular, the project will: (1) evaluate the accuracy of the habitat model and the nowcasting to predict the probability of medusa distributions in Chesapeake Bay and its tributaries, (2) determine variables that are key in defining the habitat of Chrysaora, (3) conduct retrospective examinations of medusa distributions in Chesapeake Bay, (4) predict how climate changes may affect future medusa distributions, (5) provide predictions of Chrysaora for input into Chesapeake Bay ecosystem management models, and (6) implement an improved, operational hydrodynamic model. The research will synthesize information on factors that influence the distribution and abundance of Chrysaora in order to better understand how this top predator affects energy flow through the Chesapeake Bay system, focusing in particular on potential impacts on the other top predators (i.e., fish). This effort will also provide documented skill assessments and a reconfiguration of the model codes and data throughout to meet NOS standards, which will prepare the model for transition to NOAA/NOS operational status. Components of the model include salinity, satellite-derived sea surface temperature and field observations. The real-time distribution of surface salinity in Chesapeake Bay is generated by running a real-time, three-dimensional hydrodynamic model. This hydrodynamic model, called C3PO (Chesapeake 3-D Physical Oceanographic Model), solves a set of mathematical equations using the existing conditions such as observed freshwater inflows, winds and water levels to predict currents, salinity and temperature distributions in the Chesapeake Bay. C3PO was designed by the NOAA Coast Survey Development Laboratory (CSDL) as the next generation water level and tide forecasting tool to replace Chesapeake Bay Operational Forecast System. Sea-surface temperatures (SST) used in this project are processed and distributed by the NOAA CoastWatch Program. A weekly SST composite is created from daily images of the Bay. Daily images are derived from data collected by the NOAA Advanced Very High Resolution Radiometer (AVHRR). Field observations of the relative abundance of sea nettles are required to evaluate the nowcast maps. Nowcasts will be evaluated by comparing them against field observations of nettles in the bay. Currently, we are using observations collected by scientists and volunteers of the Alliance for Chesapeake Bay.