Aug 31

By protecting just four percent of our oceans, we could protect the majority of the world’s marine mammals, say researchers.

According to scientists at Stanford University and the National Autonomous University of Mexico, protecting this small percentage of ocean would protect enough critical habitat to help conserve many of our ocean-dwelling mammals.

Photo of blue whale calf breaching

Blue whale calf breaching

Paul Ehrlich, co-author of the study and a professor at Stanford University, said, “It’s important to protect marine mammals if you want to keep the ocean’s ecosystems functional. Many of them are top predators and have impacts all the way through the ecosystem. And they’re also beautiful and interesting.”

Some of the world’s most charismatic conservation icons are marine mammals, such as the polar bear and the world’s largest animal, the magnificent blue whale. In total, there are 129 species of marine mammal living in our oceans; however, around a quarter of these are currently facing extinction.

Polar bear swimming, photo

Polar bear swimming

Mapping marine mammals

The researchers looked at areas where conservation measures could protect the most species, as well as those that are most vulnerable to extinction. To do this, the team used maps which showed where each mammal was found, and overlaid them to produce one big map. They were then able to pinpoint which locations had the highest numbers of different marine mammal species in the same area, the first study to do so on such a large scale.

According to co-authors Sandra Pompa and Gerardo Ceballos of the National Autonomous University of Mexico, the researchers were surprised to find that most species of marine mammal were found in relatively few key locations.

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”.

The researchers identified the 20 conservation sites based on three main criteria – how many species were present at the site, how severe the risk of extinction was for each species, and whether any species found in the area were unique. They also considered whether an area held habitats of special importance, such as breeding grounds or migration routes.

Californian sea otter swimming, photo

Californian sea otter swimming

Nine key sites

After compiling and analysing their data, the scientists discovered that protecting 9 out of the 20 sites that they had identified would protect habitat for 84 percent of the world’s marine mammals.

The nine sites are located off the coasts of Baja California (Mexico), eastern Canada, Peru, Argentina, north-western Africa, South Africa, Japan, Australia and New Zealand. Although they cover just four percent of the ocean, each of the 9 sites have particularly high species richness, and together they provide habitat for a grand total of 108 marine mammals.

Having identified the nine key conservation sites, the researchers also looked at how threats such as pollution and shipping affected the numbers of species that were found at each location.

According to Pompa and Ceballos, “At least 70 percent of the richness areas coincide with regions highly impacted by humans. This is powerful information that obliges us to enhance marine conservation.”

Although the study identified 9 key conservation sites, the researchers are keen to emphasise that the remaining 11 sites also harbour numerous marine mammals, including species which are found nowhere else in the world. Protecting these sites will be just as important to ensure the future of many unique species.

Read the full article at Science Daily

Read the paper in the Proceedings of the National Academy of Sciences.

Find out more about marine mammals on ARKive

Helen Roddis, ARKive Species Text Author

  • Anthony Davis (September 4th, 2011 at 7:50 pm):

    I find Arkive to be interesting and in-depth, as one would expect from Sir David. I have been a fan of his for years. I live in Barbados where the Hawksbill and Leatherback turtles nest and we were having problems with the nest sites until a group of people joined together to protect them.

    I wish you all the best in your endeavour to protect wild life, because when one species goes it has a ripple effect.

    Anthony Davis

  • Katie (September 8th, 2011 at 1:17 am):

    I’m glad to say that my area, Central California, has begun implementing a suite of marine protected areas to address this problem. I do wonder if it will be enough though. The article has listed the threats in this area as “oil and gas exploration, waste dumping and other discharges, fisheries”. These problems can affect marine mammal populations with our without officially protected habitat plots. Some habitats, especially those with endemic marine mammals such as the sea otter, will require other measures to prevent extinction.