American movie star Leonardo DiCaprio unveiled Thursday a free technology that allows users to spy on global fishing practices, in a bid to curb illegal activity in the oceans and rebuild imperiled fish stocks.

The technology, known as Global Fishing Watch, was officially released to the public during the Our Oceans Conference hosted by US Secretary of State John Kerry in Washington on Thursday and Friday.

"Today, this unprecedented technology is available to everyone in the world. I encourage everyone to go check it out," DiCaprio told the conference.

"This platform will empower citizens across the globe to become powerful advocates for our oceans."

Available at GlobaFishingWatch.org, the technology aims to offer a crowd sourced solution to the problem of illegal fishing, which accounts for up to 35 percent of the global wild marine catch and causes yearly losses of $23.5 billion, according to the UN Food and Agriculture Organization.

Overfishing is also a growing problem worldwide, with about two thirds of fish stocks in the high seas either over exploited or depleted, said the FAO.

Some of the planet's largest fish, including tuna and swordfish, are below 10 percent of their historical level.

Using satellite technology combined with radar aboard boats, the platform allows people to zero in on areas of interest around the world and trace the paths of 35,000 commercial fishing vessels.

"It gives the public an opportunity to see what is happening, even out in the middle of the ocean," said John Amos, president and founder of SkyTruth, one of three partners in the project along with Google and Oceana.

"We need the public to be engaged to convince governments and convince the seafood industry that they need to solve the problems of overfishing," Amos told AFP.

"If you can't see it and can't measure it, you are not going to care about it and it is not going to get solved."

- DiCaprio-funded -

The project has cost $10.3 million over the past three years to build, with $6 million of those funds contributed by the Leonardo DiCaprio Foundation in January.

In order the make the data available for free, Oceana and its partners negotiated a deal with the satellite company Orbcomm to use its three-day old data, which is described as "near real-time," along with historical records.

Although the delay means that any criminals won't be nabbed instantaneously, advocates say the technology will open the world's waters to public watchdogs in a way that has never been done before.

"We think it is going to have a lot of impact, first of all just the deterrent effect of vessels knowing that we could see them if they are doing something they are not supposed to be doing," Savitz said.

"You can look at an area you are interested in, zoom in and see what data we have."

- Possible uses -

For instance, users could zero in on a marine protected area and see if any boat tracks have crossed into waters where they should not have been.

One could scan the map for any evidence that large vessels are fishing in areas that are reserved for small-scale fishermen.

Vessels can be tracked by name or by country, or by traffic inside exclusive economic zones.

The paths of ships are visible, including zigzag paths that could indicate vessels are avoiding shore to offload their catch on to other ships undetected, or that other illegal operations or human rights abuses may be under way.

Savitz said some capacities may be beyond the ability of the average Internet user, but that experts are available via the website to help with specific questions.

Future versions of the technology may even include tagging data for marine animals, so that the paths of whales and sharks and other fish might be visible alongside the vessel activity, she said.

Currently, Global Fishing Watch does not include every vessel, only those that broadcast data from the Automatic Identification System, collected by satellite and terrestrial receivers and meant mainly as a safety mechanism to avoid collisions.

Many of the world's largest fishing vessels are required by the International Maritime Organization to use AIS.

AIS can be turned off if the boat operator is doing something illegal, but Savitz said that such an on-off action would likely be apparent by tracing the boat's appearing and disappearing tracks.

Already, the government of Kiribati has used Global Fishing Watch data to unmask illegal fishing in the Phoenix Islands Protected Area, declared off-limits to commercial fishing on January 1, 2015.

The owners of the vessel had to pay a $1 million fine and also made a "goodwill" donation of another $1 million grant, Oceana said.

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

Obama addressed the first day of the Our Ocean conference, where ministers and envoys from some 90 countries met with environmental experts to announce conservation measures.

Building on two previous annual meetings, delegates brought plans to protect the marine environment from pollution, overfishing and the effects of climate change.

And they heard Obama's announcement of the 4,913-square-mile (12,725-square-kilometer) Northeast Canyons and Seamounts Marine National Monument.

This is an area in the Atlantic off the coast of New England with three deep undersea canyons 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 to stocks of salmon, lobster and scallops.

"I grew up in Hawaii. The ocean's really nice there," Obama said.

"If we're going to leave our children with oceans like the ones that were left to us, then we're going to have to act, and we're going to have to act boldly."

The new reserve follows Obama's recent expansion of the huge Papahanaumokuakea Marine National Monument off Hawaii, and 20 other countries are to declare new areas.

"These are problems we can solve. And part of the power of conferences like this is to insist on human agency, to not give in to hopelessness," Obama said.

"Nature's actually resilient if we take care to just stop actively destroying it. It'll come back."

Britain was one of the first to show its hand, announcing a plan to double the area of protected ocean around its far-flung overseas territories.

Fully protected marine reserves are to be set up around the Pitcairn Islands in the South Pacific and St Helena, Tristan da Cunha and Ascension in the South Atlantic.

The plans impose a permanent ban on commercial fishing in an additional one million square kilometers (386,100 square miles) of ocean, according to Britain's Foreign Office.

Meanwhile, the Global Environment Facility, the Wildlife Conservation Society, the Blue Moon Fund and the Waitt Foundation announced $48 million to help developing countries create and expand tropical marine reserves.

Delegates hope that by 2020, 10 percent of the world's oceans will become protected reserves, with fishing and oil exploration banned or tightly restricted.

And American movie star Leonardo DiCaprio unveiled a new crowd-sourced technology, Global Fishing Watch, to help concerned people track illegal fishing by satellite.

- Ocean protection -

The conference was hosted by US Secretary of State John Kerry, who hopes the Our Ocean summits that he pioneered will continue after he leaves office next year.

The first Our Ocean summit was held in Washington in 2014, followed by Valparaiso in Chile last year. Next year's meeting will be hosted by the European Union.

"I think Kerry will continue to be a champion of the oceans because this is his strong passion," UN Environment Program executive director Erik Solheim told AFP.

"But they have also institutionalized it, the EU and Malta will host it next time ... This is gaining speed in so many different ways now."

Kerry recalled that at the previous summits, nations from across the world committed to designate over six million square kilometers (2.3 million square miles) of ocean.

Kerry said over two days the delegates would announce 120 preservation projects and $2 billion in new funding to protect more than two million square kilometers of sea.