In the ongoing effort to make the comings and goings of whales and dolphins more clear to ships and other boats, a new and ground-breaking set of maps has been created. The idea is to continue opening up saving routes in the busy waters of the U.S. East Coast and Gulf of Mexico.
The new maps are freely available online and show population densities as well as seasonal movements of 35 species of whales, dolphins and porpoises. Many of the animals are threatened or endangered.
"These maps show where each species, or closely related group of species, is most likely to be at any given time of year," Laura Mannocci, a postdoc researcher at Duke University's Marine Geospatial Ecology Laboratory (MGEL), said. "This makes it easier to monitor and manage them, and reduce the risk of harmful interactions."
The maps put together data from surveys covering almost 1.1 million linear kilometers of ocean area -- as well as from 26,000 sightings gathered over 23 years by five institutions' researchers.
"Though protected under U.S. law, many cetacean species still face persistent threats from accidental ship strikes, fishery bycatch, offshore energy development, pollution, climate change and underwater noise from human activities," lead researcher Jason J. Roberts at MGEL, said.
"Our maps give government agencies and other interested parties better tools to help protect these highly mobile animals and guide future ocean planning, including decisions about the siting of wind energy and oil and gas exploration along our coasts," Roberts said.
The work was recently published in the journal Scientific Reports.
Some things were revealed by integrating the data. For instance, it's clear now that any continental slope is an important foraging habitat on a seasonal basis for pilot whales and other large delphinoids. This is a group of toothed whales that includes belugas and orcas. Underwater canyons and seamounts are also preferred habitats for many beaked and sperm whales.
"Insights provided by these new maps can be very influential in shaping the outcomes of these decisions because population density estimates are used by U.S. government agencies to enforce the Marine Mammal Protection Act and Endangered Species Act," Patrick N. Halpin, director of MGEL in Duke's Nicholas School of the Environment, said.
Already, the new models are being used for planning by regional ocean management bodies in two East Coast regions, by the Northeast Regional Planning Body and the Mid-Atlantic Regional Planning Body. The system of planning bodies was established by Presidential Executive Order in 2010.
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