"We want to estimate in real time where sea nettles are, and when," said Christopher Brown, the co-author who initiated the project. Brown is an oceanographer at the NOAA/National Environmental Satellite Data and Information Service, in Camp Springs, Maryland. "If you know the habitat for a species you should be able to predict where it occurs," Brown said.
For instance Orbimage, an earth imaging company, produces "Fish Finding Maps" by tracking sea surface temperatures from government weather satellites and plankton concentrations from a private satellite, OrbView-2.
Brown's team takes a similar approach to find jellyfish. Using a computer program, they plug in data like freshwater inflow into the bay, wind speed, and water levels and temperature at the mouth of the bay. The program generates a "habitat model" for the Chesapeake that predicts salinity and water temperature throughout the bay and its tributaries.
Salinity and temperature most influence the jellyfish population. The saltier the waters, the better for the jellies. Using the habitat model they estimate where the jellies are.
Brown's original research goal was to track toxic algae blooms. But studies lag on the blooms, which depend on a complex interplay of factors.
By contrast, researchers know more about sea nettles and their habitats, which made the creatures a good target for the first forecasting.
Satellites can pinpoint some algae blooms but not necessarily determine the species that cause them. Often, people discover an outbreak by stumbling upon a fish kill.
The worst algae blooms wreak havoc on the fishing industry and on recreation along the coasts. Toxins can accumulate in fish and shellfishand sicken the people who eat them.
The number of blooms is growing as a result, experts believe, of nutrients and fertilizers in farm and sewage run-off.
"A model that could predict the occurrence of harmful blooms could target our monitoring," said Robert Magnien, director of the Tidewater Ecosystem Assessment of the Maryland Department of Natural Resources.
Predicting blooms would allow time to post warnings and curtail fishing. Eventually researchers hope to control the conditions that cause the blooms.
"Nowcasts" on the Chesapeake are a step toward safer waters everywhere.
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