Satellite data and migration models are used to identify areas that are dangerous to marine life. Whales especially are prone to being hit by passing ships or becoming entangled in fishing gear. Scientists are analyzing their movements in an effort to avert such harm.
WhaleWatch project leader Dr. Helen Bailey of the University of Maryland Center for Environmental Science said: "We will be analyzing the largest satellite tracking dataset for large North Pacific whales and combining it with satellite-derived environmental data to provide us with key information on where and when the whales are found and why." She gets close enough to her work to get the wonderful photo image that introduces this article.
Dr. Bruce Mate, professor of fisheries and wildlife at Oregon State University said: "We know, for example, that the West Santa Barbara Channel off California is a place where blue whales feed and it is right in the middle of shipping lanes to the Los Angeles harbor. Identifying the seasonal trends, as well as the geographical movement, may help policymakers find ways to better protect the whales." Gray whales migrate more than 10,000 miles between feeding grounds and breeding grounds where they also give birth, from the northern Bering Sea to the coast of Baja California, Mexico, navigating dangerous situations all along the way.
Tracking our fine finned friends is not a new phenomena. Attempts to track Atlantic salmon migration first occurred as early as 1873 in Maine?s Penobscot River. By the 1950?s, SONAR (SOund Navigation And Ranging) acoustic tags improved the results. Forty years ago, data loggers which measured time, depth internal temperature, swim speed and heart rate greatly enhanced scientists? understanding of life in the waters. Finally, the 1990?s brought advances in computer and satellite technology which virtually eliminated the need to recapture a fish to obtain the data archived in its tag.
The archival tags posed a logistical problem. An improved version, pop-up archival tags (PAT) are set to drop off the animal in 30-90 days and float to the surface. The tag then sends data to the polar orbiting Argos satellite until its battery runs out, in about two weeks. The data, however, remains intact, so it can be retrieved if the tag happens to be found. Finding it could be like looking for a needle in a haystack. The floating mini PAT is only 115mm long, not including the antenna, by 40mm wide and weighs 53g.
Another design, the SPOT (Smart Position or Temperature Transmitting Tag), sends its data to a satellite when its antenna breaks the surface of the water as the animal comes up for air. It turns off when a saltwater switch senses it has gone under water again. The tag collects and sends information regarding pressure, speed and water temperature. Doppler shift between transmissions helps determine location. The life of the SPOT tag, made by Wildlife Computers, is about two years. The company works out of offices in Redmond, Washington and St. John’s, Newfoundland, Canada. Wildlife Computer?s software, called WC-DAP, decodes, summarizes, visualizes and exports data collected by their tags.
Depth and temperature illustration of data collected from tagged animals? activity
Not only the movements of the marine life, but the environment in which they find themselves is studied. The University of Maryland Center for Environmental Science was doing research about oysters in 1925. The Center has a unique statutory mandate to conduct a comprehensive scientific program to develop and apply predictive ecology for the improvement and preservation of Maryland?s physical environment. An SRDL, Satellite Relay Data Logger compresses larger sets of data for transmission through the Argos satellite. Their CTD tags record salinity, temperature and depth for identifying ocean currents. These tags go on elephant seals, sea lions and leatherback sea turtles.
The National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NOAA) is involved with WhaleWatch in the current project scheduled to run three years. Results will be posted on the NOAA website.
All this human activity is guided by the thought expressed by Peter Benchley, the author of the haunting thriller Jaws: "If we kill everything in the ocean, and if we pollute the ocean to a point where it can’t sustain life, we’re committing suicide."