A new study co-authored by a University of Hawaii at Hilo professor says the world faces an unprecedented mass extinction of marine life unless there’s a dramatic shift in ocean management with constraints on fishing and hunting.
The study, published Wednesday in the journal Science, suggests that the catastrophe would exceed any of the worst extinctions of the past.
“Even under the most optimistic business-as-usual scenario, vertebrate extinctions could far exceed those of any other time since the planet was struck by a meteorite leading to the extinction of the dinosaurs 66 million years ago,” said Matthew Knope, assistant professor of biology at UH Hilo.
Knope collaborated with lead author Jonathan Payne and Noel Heim of Stanford University, Andrew Bush of the University of Connecticut and Doug McCauley of the University of California, Santa Barbara.
The study compared the ecological traits and extinction-threat level of animals in oceans today to the ancient past, which experienced five major periods of mass extinction.
While no preference for body size was seen in previous extinctions, the greatest threats in modern oceans are to creatures of larger body size.
That’s bad news, according to the study, because larger animals — whales, sharks, tuna, giant clams — are critical to ecosystem function because they are usually found at the top of the food chain. They are also important for nutrient cycling and for turning over the sediments on the seafloor.
The study suggests that commercial fishing and hunting are currently the major threats to marine animals.
“Humans tend to target large things first,” Knope said.
The study concludes: “Without a dramatic shift in the business-as-usual course for marine management, our analysis suggests that the oceans will endure a mass extinction of sufficient intensity and ecological selectivity to rank among the major extinctions” of all time.
Is it inevitable?
“It’s up to us,” Knope said.
The northern elephant seal, for example, was brought back from the brink of extinction, he said. One hundred years ago, only about 100 animals were left. Today, thanks to protections and recovery efforts, there are an estimated 200,000 northern elephant seals, and they are a species of least concern on the International Union for Conservation of Nature’s Red List of threatened species.
The study’s publication comes in the wake of President Barack Obama’s announcement of the expansion of the Papahanaumokuakea Marine National Monument, which placed as off limits to fishing and other commercial activities an area twice the size of Texas.
The World Conservation Congress, meeting in Honolulu earlier this month, also voted to support the protection of 30 percent of the world’s oceans in a move to fight diminishing biodiversity, overfishing and damage to coral and unique underwater geological features.
This week, government officials, business leaders and scientists will attend the third Our Ocean conference in Washington, D.C., hosted by U.S. Secretary of State John Kerry. The conference is expected to address a variety of issues, including marine protected areas, sustainable fisheries, marine pollution and ocean-related climate change.
Knope said he and his colleagues hope that Obama’s move to expand Papahanaumokuakea will encourage other countries to make similar conservation actions in an effort to curtail the mass extinction.
