A new survey of extinction patterns suggests the ocean's largest species are most likely to be wiped out by humans.

"We've found that extinction threat in the modern oceans is very strongly associated with larger body size," Jonathan Payne, a paleobiologist at Stanford University, said in a news release. "This is most likely due to people targeting larger species for consumption first."

Payne and his colleagues look at the relationship between risk of extinction and body size among mollusks and vertebrates over the last 500 years. The researchers then compared modern extinction patterns to prehistoric extinction patterns. Their analysis looked at the fossil record stretching back 445 million years, but focused most intently on the last 66 million years.

Their findings were detailed in a new paper, published this week in the journal Science.

"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 Noel Heim, a postdoctoral researcher in Payne's lab and co-author of the new study.

Specifically, larger species in the modern ocean are more likely to become extinct. Scientists calculated that over the last 500 years, a 10-fold increase in body mass corresponds with a 13-fold increase in the threat of extinction.

Previous studies have highlighted the role the ocean's largest creatures play in recycling nutrients throughout marine ecosystems. Therefore, scientists hypothesize that the disappearance of the ocean's largest species is especially damaging and disruptive to marine food chains.

The worrisome pattern recalls the disappearance of megafauna -- mammoths and saber-toothed tigers -- from the planet's continents at the end of the last ice age.

"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."

Researchers hope their findings instill urgency in the efforts to better protect and manage the ocean's largest species.

Obama declares new marine reserve at Oceans summit
Washington (AFP) Sept 15, 2016 - US President Barack Obama was to announce the creation of a new marine reserve on Thursday as Washington hosted a major world summit on protecting the planet's oceans.

The American leader was to address the first day of the Our Oceans meeting, where ministers and representatives of some 90 countries will meet with environmental experts and activists.

Building on two previous annual meetings, delegates will unveil measures to protect the marine environment from pollution, over fishing and the effects of climate change.

And one of the headlines on day one will be Obama's announcement of the 4,913-square-mile (12,725-square-kilometer) Northeast Canyons and Seamounts Marine National Monument.

This is an area off the Atlantic coast of New England with three undersea canyons deeper than the Grand Canyon and five submerged mountains, home to rare deep sea coral and whales.

Commercial fishing will be restricted in the area, where scientists have warned that warming ocean temperatures are a threat of stocks of salmon, lobster and scallops.

The new national monument follows Obama's recent expansion of the huge Papahanaumokuakea Marine National Monument off Hawaii, and several more countries are expected to declare new reserves.

The summit is to be hosted by US Secretary of State John Kerry, who himself hails from New England and has made ocean protection a priority during his three years in office.

"During our gatherings in 2014 and 2015, nations from across the world committed to designate over six million square kilometers of ocean as marine protected areas," Kerry said.

"We will build on those achievements by announcing over 120 significant ocean conservation projects, including almost $2 billion in new pledges and commitments to protect more than two million square kilometers in new or expanded marine protected areas."

US under secretary of state for economic growth, energy and the environment Catherine Novelli told reporters 90 countries would be represented along with NGOs and the private sector.

In addition to announcing new marine reserves, the delegates will discuss scientific advances in monitoring pollution and fishing and funding for clean-up measures and protection.