Preserving nine specific marine habitats could protect eighty-four percent of marine mammals, but those same areas are also heavily effected by humans.
The nine areas make up only four percent of the ocean, but are home to 108 of the 129 known marine mammal species, one-quarter of which face extinction, according to a study recently published in the Proceedings of the National Academy of Sciences.
Researchers at Stanford University and the National Autonomous University of Mexico overlaid maps of each marine mammal's ranges to find places where at least 10 percent of the species' habitats overlapped. They found 20 areas that included all species.
"This is the first time that the global distribution of marine mammal richness has been compiled and presented as a map," said co-authors and ecologists Sandra Pompa and Gerardo Ceballos of the National Autonomous University of Mexico in a press release. "The most surprising and interesting result was that all of the species can be represented in only 20 critical conservation locations that cover at least 10 percent of the species' geographic range."
Of those 20 areas, nine had particularly high numbers of species living together. The areas are off the coasts of Baja California in Mexico, eastern Canada, Peru, Argentina, northwestern Africa, South Africa, Japan, Australia and New Zealand. The other 11 areas were home to species found nowhere else and therefore highly vulnerable: Hawaiian Islands, Galapagos Islands, San Félix and Juan Fernández Islands, the Amazon River, Mediterranean Sea, Indus River, Yang-tse River, Baikal Lake, Caspian Sea and Kerguelen Islands.
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The researchers also looked at how pollution, local climate disruption and commercial shipping overlapped with the critical habitats.
"At least 70 percent of the richness areas coincide with regions highly impacted by humans," said Pompa and Ceballos. "This is powerful information that obliges us to enhance marine conservation."
"It's important to protect marine mammals if you want to keep the ocean's ecosystems functional," said study co-author and biologist Paul Ehrlich of Stanford University. "Many of them are top predators and have impacts all the way through the ecosystem. And they're also beautiful and interesting."
The researchers did not look at other human impacts such as overfishing or global climate change. But the researchers believe these impacts could make the conservation of the critical habitats even more difficult. And the situation will get worse as more people compete for fewer resources in the future.
"The next 2 billion people we're going to add to the planet are going to do much more damage to the ocean than the previous 2 billion did," said Ehrlich. "Humans reach for the low-hanging fruit first, so to speak, but for the ocean that's gone now."
"We need to conserve what's left of the biota of the planet, both on land and in the sea," said Ehrlich. "We need to know where the biodiversity is before we can take many of the necessary steps to conserve it. This is just a start on the mammals of the sea."
IMAGE 1: Adult female Bottlenose Dolphin with two young at side, Inner Moray Firth, Scotland May 2005 (Peter Asprey, Wikimedia Commons)
IMAGE 2: Humpback Whale (Octavio Aburto)