Protecting the ocean may have benefits. Scientists found that if we protect 30 percent of the ocean from human influence, it's possible we may be able to help fish stocks rebound and create a better oceanic environment.

"There's been huge interest and controversy over how much of the sea we really need to protect in order to safeguard life there and the benefits it provides to humanity," Callum Roberts of England's University of York said. "The science says we should raise our ambitions to protect something of the range of 30 to 40 percent of the oceans from exploitation and harm."

The United Nations currently has a target of 10 percent for protection by 2020. However, in 2014, the World Parks Congress made a recommendation of at least 30 percent.

In this latest study, researchers identified studies that asked how much of a particular ocean area should be in Marine Protected Areas (MPAs) to achieve a particular management goal. The scientists grouped them according to five goals: protecting biodiversity, ensuring population connectivity among MPAs, avoiding fisheries and population collapse, maximizing or optimizing fisheries value or yield and satisfying multiple stakeholders.

"What we've done is to extrapolate from their results, to blend the results for a whole variety of different approaches that people have taken, and to come up with a big-picture figure," Roberts said. "The answer isn't a few percent of the sea, which is what we have protected right now. It's a few tens of percent of the sea. The U.N. 10 percent by 2020 target is politically ambitious, but it is only a waypoint, not the endpoint for effective ocean management."

The findings show that 10 percent is too low in order to safeguard marine life and have sustainable fisheries in the long term.

"While at first glance the figures we have presented seem large, they are not surprising," Bethan O'Leary, one of the researchers, said. "Wildlife and habitats evolved in the absence of human industrial exploitation so it is only to be expected that intensively exploiting a large fraction of the oceans is not a viable option in the long term. The natural world needs substantial space free from significant human impact to thrive. The fact that we currently exploit far too much of the sea is one of the root causes of recent fisheries decline and environmental degradation."

The findings were published in the March edition of the journal Conservation Letters.