At the "Our Oceans" conference in Chile - which aimed to insure the health and sustainability of the ocean for future generations - both Chile and the United States announced creation of new marine sanctuaries.

New Zealand also recently declared a huge swath of ocean as off-limits for fishing, while US President Barack Obama announced new measures to combat illegal fishing.

DW's environment desk caught Pew Charitable Trusts' illegal fishing project director Tony Long fresh from the conference in Chile, to take a closer look at ocean conservation.

Deutsche Welle: How significant are these announcements when it comes to protecting the oceans for future generations?

Long emphasized the effectiveness of marine preserves

Tony Long: I think the announcements are very significant. The leadership shown by Chile and the US set an example for other countries around the world to follow. Marine reserves are an excellent way of protecting marine habitat and ensuring pristine seas. And when you add that to the US idea of leading the world on the most appropriate use of technology through their Sea Scout announcement, you really start to get a good package for ocean protection.

The problem with illegal fishing is it is global. And it's not only global through localized illegal fishing - it's distanced water fleets, and fleets moving across boundaries. So the only way to really combat it is to share information and work together.

So how big is that problem?

The figures that tend to get used are that around one in five fish is likely to have illegal activity linked to it. That's 23 million tonnes of fish per year - which is the equivalent of up to $23 billion (20 billion euros) worth of fish a year.

Sea Scout uses technology and surveillance to allow countries to share information and counter illegal fishing

Which areas are worst hit?

It tends to be the countries with the least resources to protect their economic zones, and those countries that are rich in fish resources - so typically coastal states of west and east Africa - but also in the Far East, around Indonesia, Thailand and the Philippines. These archipelagos are extremely difficult fisheries to monitor.

What form does the illegal fishing take?

The type I'm looking at is the industrial size vessels that tend to come from far away, fishing the economic zones of countries that don't have the resources to protect them. Generally, they will not have a license or will use a duplicated license, or overfish and underreport. Or they transship - exchange fish at sea, so effectively "launder" fish, in the same way money is laundered. This is why it's a very complex problem to solve.

African coastal states are short on resources to protect their waters from illegal trawling

Should governments in the consuming countries be doing something about this?

There are several ways to tackle illegal fishing: traditional enforcement methods, vessels out at sea patrolling, trying to capture these vessels red-handed. But that's extremely expensive and inefficient when you consider the size of the ocean and the amounts of assets that would need.

So markets are actually a key area. Any country that wants to import fish and then export it again should ratify the Port State Measures agreement. This is a UN protocol that allows countries that suspect illegal fishing is happening to simply turn the vessels away. This a very effective measure that costs these illegal fishers money.

Is there anything the ordinary consumer can do?

They have got a problem. It's extremely different at the moment to trace where the fish is from. Most people will simply see something as straightforward as Indian Ocean or Pacific Ocean written on the fish they are buying. I think the first thing consumers can do is start to ask more questions of the retailers and restaurants where they buy their fish.

The Pacific jack mackerel is a fish stock newly emerging as overfished

President Obama announced a new campaign to combat illegal fishing. How successful can a campaign like that be, and what will decide its success?

This kind of campaign and announcement of protected regions are key and link in with what European Union is doing. Commissioner Vella has put a very strong hand into protecting countries against illegal imports. So when you have the US and the EU working together - the two largest markets, and the EU has one of the largest fleet - you can start to make a change. And we hope to see the next-biggest market, Japan, joining those two.

There's a huge focus on the impacts of climate change right now, with the Paris conference coming up at the end of the year. Does that detract attention from the need to protect our oceans against overexploitation?

Climate change, over-fishing and illegal fishing are all linked in one way or another. The bad practices that occur from illegal fishing can damage the ecosystem - whether it be trawling and ripping up corals, or fishing the wrong species at the wrong time, or taking the wrong catch. It all has an effect on the broader ecosystem. And with ocean acidification and the changes that are taking place now scientifically proven, that's going to reduce the amount of fish people can catch, if we don't start to look after it. So actually it should all be seen as one.

Tony Long directs the Pew Charitable Trusts' work to end illegal fishing.

Interview: Irene Quaile