New research reveals an unprecedented pattern of extinction in the oceans: larger marine animals face a higher risk of extinction (thanks primarily to humans) than smaller ones.
“We’ve found that extinction threat in the modern oceans is very strongly associated with larger body size,” Jonathan Payne, a paleobiologist at Stanford’s School of Earth, Energy & Environmental Sciences, said in a news release. “This is most likely due to people targeting larger species for consumption first.”
Payne and his colleagues studied the extinction threat level and ecological traits (like body size) of vertebrates and mollusks over the past 500 years and compared it with ancient times.
“We used the fossil record to show, in a concrete, convincing way, that what is happening in the modern oceans is really different from what has happened in the past,” said study co-author Noel Heim, a postdoctoral researcher in Payne’s lab.
“What our analysis shows is that for every factor of 10 increase in body mass, the odds of being threatened by extinction go up by a factor of 13 or so,” Payne said. “The bigger you are, the more likely you are to be facing extinction.”
This pattern has dangerous implications for the overall health of marine ecosystems because things that happen at the top of the food web tends to trickle down to other groups.
Why are humans to blame? Well for starters, while this pattern of extinction is new to the oceans, it’s been seen before on land.
“We see this over and over again,” Heim said. “Humans enter into a new ecosystem, and the largest animals are killed off first. Marine systems have been spared up to now, because until relatively recently, humans were restricted to coastal areas and didn’t have the technology to fish in the deep ocean on an industrial scale.”
But that has changed.
“It is consistent with the tendency for fisheries to first exploit larger species and subsequently move down the food web and target smaller species,” said study co-author Matthew Knope, a former postdoc in Payne’s lab who is now an assistant professor of biology at the University of Hawai‘i at Hilo.
The good news, Payne said, is that it’s not too late.
“We can turn this situation around relatively quickly with appropriate management decisions at the national and international level.”
Watch the video to learn more about mass extinctions:
For more information:
- Read the Stanford news release: Larger marine animals at higher risk of extinction, and humans are to blame, Stanford-led study finds
- Read the full study: Ecological selectivity of the emerging mass extinction in the oceans
Copyright © 2016 by Marine Science Today, a publication of Marine Science Today LLC.