In 1987, a biologist went undercover aboard a commercial tuna fishing vessel. A video he took made headlines around the world: hundreds of dolphins circled in purse seines, drowning in distress.

Before that, few people had given much thought to bycatch – the fish and marine animals caught while trying to catch something else. It was out of sight, out of mind. But now everyone could see the shocking images.

In the decades that followed, some of the toughest bycatch problems were solved. Even so, bycatch remains one of the toughest obstacles to making the world’s seafood products more sustainable.

So if better nets and better rules aren’t the complete answer, what are? Our new research suggests that part of this is the human factor. The more skilled the fishermen, the more likely they are to avoid incidental catches.

We need more than technology and top-down solutions

Until now, solutions to bycatch have tended to be technical or regulatory. Think of modified fishing gear so non-target animals can escape, or closing high bycatch areas to fishing during certain seasons or when bycatch exceeds a threshold.

Although they can work, these approaches are often expensive, especially for small or low-value fisheries. They also require increased monitoring and enforcement to ensure fishing fleets follow the rules.

Top-down regulatory approaches are often met with stubborn resistance from fishermen. Commercial fishing vessel operators may feel like they are being targeted by experts who don’t understand the challenges they face.

Technology and regulation have so far failed to solve the most difficult bycatch problems.

It has proven very difficult, for example, for trawlers to stop catching endangered sharks, rays and sea snakes at unsustainable rates – even though the same trawlers are now sporting smart tracking devices. exclusion of turtles which have reduced sea turtle mortality in the northern Australian prawn fishery.

Or think of gillnets, which in Australia continue to catch and kill endangered sawfish, dugongs and sharks. When anglers change their technique to avoid catching one type of bycatch, they often see an increase in bycatch of other species.

Read more: Buying Australian oysters and farmed barramundi: 5 tips to make your summer seafood feast sustainable

From time to time, bycatch will resurface in the minds of the public. You might see grotesque images of adorable sea animals mangled in nets spreading across social media as part of a new bycatch campaign.

Progress is there, but it is slow, costly and at risk of being pushed back. The prevailing attitude in the industry is that bycatch should be reduced wherever possible, but some is unavoidable.

How increasing the skills of fishers could further reduce bycatch

Many fisheries managers intuitively understand the importance of the human factor in managing environmental issues, such as bycatch. They know the ships and captains of their fleet. And they know that most compliance issues can usually be traced to a small number of problematic vessels.

We put these assumptions to the test in our new research on Australian fisheries and found that to be true.

We found a clear trend across different locations and gear types, where specific anglers were able to maintain high target species catches with lower bycatch rates. In short, skilled anglers can avoid catching dolphins, seabirds, sharks and other bycatch species.

It was surprisingly difficult to test managers’ assumptions with data. So how did we show this?

It is well known that fishing skills vary. As a result, some fishermen and boats are consistently more profitable. If fishers have varying skills in catching their target species, it follows that they will have varying skills in avoiding bycatch species.

The variable competence model had never been tested against bycatch rates. This is partly because we need a lot of data to isolate individual behavior and skill from many other factors affecting bycatch. For example, fishermen often associate the high number of bycatch with environmental factors, such as specific fishing areas or breeding seasons.

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While these factors affect bycatch levels, we were able to determine the effect of individual vessels using robust datasets collected by scientific observers in five major commercial fishing areas in Australia.

We found a clear signal in the data. Overall, individual vessels caused differences in bycatch rates more than fishing location, season, or year. In each of the five fisheries, we found high performing operators able to consistently achieve a high catch of target species and low bycatch, as well as low performing operators, who did the opposite. This even applies to fishing gear known to have high bycatch globally, such as bottom trawls and gillnets.

We don’t know exactly what fishers are doing to avoid bycatch. Fishing “skill” is likely a mix of experience and knowledge of the environment, the ability to effectively manage a crew, use and maintain gear, and react quickly to changing conditions at sea. These behaviors nuances are not recorded in the logbooks and are difficult to describe, meaning we will have to work directly with fishermen to really untangle the ship effect.

Can we improve our anglers?

Now that we know that the skills of our anglers matter so much, we have the opportunity to reduce bycatch even more than we thought possible. We can challenge the belief that bycatch is an inevitable part of fishing.

Harnessing the skills and knowledge of successful fishers can motivate behavior change in ways that are more likely to succeed than top-down regulations or new technologies.

We can consider incentives to encourage qualified and experienced fishermen to spread their knowledge and skills. This would raise the bar for poorly performing fishermen and help the industry avoid penalties due to the actions of a few very damaging boats.

If we work closely with successful fishermen, we could see even more innovation in reducing bycatch, as well as other long-standing issues such as waste management and abandoned “ghost nets” that can keep killing for years.