It’s the fascinating new Netflix documentary everyone’s talking about. Seaspiracy, the dramatic investigation into the environmental impact of the global fishing industry and the threat it poses to our precious oceans, has become a must-see. But alongside the hype there’s been the inevitable backlash. For some clarity, we spoke to one of the UK’s leading marine biologists Dr Bryce Stewart, a fisheries biologist from the University of York who has spent his whole life researching ‘sustainable solutions to ocean management’, to get his take on the documentary and find out how we can all help do better by the world’s fish (including whether we need to stop eating it). 

Seaspiracy has been rather controversial - what’s your view on the doc?

It highlighted the problem of overfishing to a new audience. Millions of people have watched it – a huge number who haven’t really thought about these issues before. Most scientists would agree overfishing is the biggest threat to the ocean ecosystem. There are other interlinking threats out there too of course, such as climate change and pollution, but if you had to focus on one, it’s overfishing.

There’s been quite a backlash. Why do you think that is?

One of the main conclusions from the film seemed to be that sustainable fishing doesn’t exist which isn’t true. Yes, overfishing is definitely a threat – a third of the world’s fish stocks are overfished – but that means two-thirds are sustainably fished. If you went back 20 years, this would be a different conversation because management authorities were often setting catch limits too high. They weren’t considering the wider environmental impacts, but now there are lots of initiatives coming not only from the government but also from the seafood industry itself.

The film also discredited the MSC label through selective interviewing and editing, but I can’t think of a single organisation that’s done more for sustainable fishing than the Marine Stewardship Council!

Seaspiracy would have been much better if it had presented not just the problems, but also some of the solutions. It did contain misleading, at times inaccurate and outdated science. It needed to be more scientifically rigorous and contain a broader range of perspectives. There were almost no interviews with people of colour. 

What are your thoughts on plastic pollution?

Seaspiracy said what’s known as the Great Pacific Garbage Patch [a collection of debris in the North Pacific Ocean] was mostly fishing gear but in reality fishing equipment only contributes to about 10% of all debris in the ocean. Instead, 80% of it comes from land-based sources – in other words, from us! It comes from people not disposing of their rubbish properly, overflow from landfill sites and from people not having the means to manage their rubbish properly in some parts of the world. They might throw it into a river, but then it ends up in the sea. Saying the fishing industry is responsible for most of the ocean’s plastic pollution just isn’t true.

Many people will stop eating fish after watching Seaspiracy. Ultimately, do you think that’s necessary to save our oceans?

No and it’s also not a realistic option for billions of people. In our world it’s estimated that around 3.1 billion – nearly half the world’s population rely on fish and shellfish as their main source of protein. If you consider people living in coastal communities or island states, for example, many don’t have alternatives.

I do some work in the Seychelles, where there’s very little land and the land they do have is mountainous and covered in rainforest mostly, so the ocean is vital to them and people there eat fish every day. If they were to stop, what would they do instead? Either fly supplies in causing a huge carbon footprint or cut down their rainforest to use the land for crops?! That’s not a realistic option and saying they should give up fish shows no respect for their culture, tradition or history.

So what’s the first thing we should look for when we’re shopping for fish?

Check for the eco label from the Marine Stewardship Council – the little blue fish with a tick on it. The MSC is a not-for-profit organisation that certifies seafood products as being sustainable via a rigorous, independent process.

There’s also the MCS Good Fish Guide App from the Marine Conservation Society which ranks seafood on a one to five rating. Choose fish with a green rating and steer clear of those in the red zone.

Which fishing methods really are the baddies to be aware of?

The reality is there’s always going to be an impact from fishing, as there is with any food production system, but we need to try and minimise that impact.

There are many different fishing methods but bottom trawling and scallop dredging (where fishing gear is towed along the seabed) tend to get bad press. For some species though that’s the only way to catch them or to catch any sufficient quantity.

It’s crucial to make sure those methods are only used in the sea’s most resilient environments and to avoid areas where the seabed is rich in biodiversity and might contain seagrass, corals or any other sensitive species. Areas of the sea that have naturally strong currents and where the sands are naturally mobile tend to be more resilient and less susceptible to the impact of fishing gear.

And which ones are better for the fish and the marine environment? 

If you get diver-caught scallops where a diver is literally going down and picking them up, one by one, that has very little effect on the wider ocean environment. Even farmed shellfish like farmed scallops, oysters and mussels have very little impact because generally they’re grown in nets or on ropes. They can actually filter the water, absorb carbon and even provide habitats for other species, so shellfish farming is one of the best choices.

So are farmed fish generally a good option?

It’s complicated. At one end of the scale, you have farmed shellfish which is a good choice. But at the other extreme, you have salmon farming. In the UK pretty much all fresh salmon is farmed, but there are several issues. These include:

1. You need to feed the salmon other fish (e.g. a special feed made from anchovies) for them to grow at the rate they need to.

2. You have to use certain chemicals and antibiotics to try and keep them healthy and those do spread into the water around them.

3. The waste from the fish can affect the seabed around the farms.

4. They can spread parasites.

5. If the salmon escape from the farm (which does sometimes happen) they could breed with any wild fish and affect their genetics.

So, in your view, instead of giving up fish, what should we be doing instead?

There are lots of things you can do to help the ocean. Many of them start at home. Reducing your carbon footprint is really important. Use public transport more, walk, ride your bike, heat your house efficiently and reduce your waste. In the UK no one lives more than 70 miles from the sea. Most of us go to the sea at least once a year – or far more often. You could take part in an organised ‘beach clean’ or just pick up any litter yourself while you’re there. Get out there and educate yourself too, using reliable sources of facts.

What other docs should we all be watching?

A Netflix adaptation is in the pipeline of an award-winning book called The Outlaw Ocean and there’s a pretty shocking 2009 film called The Cove where a group of activists go on an undercover mission to expose dolphin hunting in Japan. Full disclosure: one of my ex-students made a film called Troubled Waters about the impact of overfishing which is available on YouTube. It’s a very balanced, scientifically accurate film. It’s only cost him £500 to make, but it’s had over 100,000 views!