Dolphins, turtles and birds don’t have to die in fishing gear – experienced anglers can avoid it

Editor’s Note: The authors of this article are currently reviewing some of the data used in their Nature paper to investigate a potential flaw. If there is an error, this article will be updated and a correction will be issued.

In 1987, a biologist went undercover on a commercial tuna fishery. A video he made made headlines around the world: hundreds of dolphins surrounded in purse seine nets, drowning in distress.

Before then, few people had given much thought to bycatch—the fish and sea creatures caught when trying to catch something else. It was out of sight, out of mind. But now everyone could see the shocking images.

In the decades since, some of the most confrontational bycatch problems have been resolved. Yet bycatch remains one of the most difficult obstacles to making the world’s seafood more sustainable.

So if better nets and better rules aren’t the complete answer, then what is? Our new research suggests that some of it is the human factor. The more skilled fishermen are, the more likely they are to avoid accidental bycatch.

Videos of dolphins like this one trapped in nets drew the world’s attention to bycatch.
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We need more than technology and top-down solutions

Until now, bycatch solutions have been mostly technical or regulatory. Think of adapted fishing gear to allow non-target animals to escape, or closing high bycatch areas to fishing during certain seasons or when bycatch exceeds a threshold.

While they can work, these approaches are often expensive, especially for small or less valuable fisheries. They also require increased supervision and enforcement to ensure that fishing fleets comply with the rules.

Top-down regulatory approaches often meet with stubborn resistance from fishermen. Commercial fishing boat operators may feel that they are being targeted by experts who do not understand the challenges they face.

Technology and regulations have so far failed to address the most challenging bycatch problems.

For example, it has proven very difficult for trawlers to stop catching endangered sharks, rays and sea snakes at unsustainable rates – although the same trawlers now have smart devices to exclude turtles that could reduce the deaths of sea turtles in the shrimp fishery in northern Australia. have reduced.

shrimp fisherman Australia
Australian shrimp trawlers have adopted turtle exclusion devices.
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Or think of gillnets, which still catch and kill endangered sawfish, dugongs and sharks in Australia. When fishermen change techniques to avoid catching one type of bycatch, they often find that bycatches of other species increase.



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


Occasionally, bycatch resurfaces in public opinion. As part of a new bycatch campaign, you may see grotesque images of lovable sea creatures mutilated in nets that are spreading through social media channels.

There is progress, but it is slow, expensive and there is a risk of relapse. The prevailing attitude of the industry is that bycatch should be reduced where possible, but some of it is unavoidable.

How improving the skills of fishermen can 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 in their fleet. And they know that most compliance issues are usually traced back to a small number of problem vessels.

We put these assumptions to the test in our new study of Australian fisheries, and we found it to be true.

We found a clear pattern between different locations and gear types, where specific fishermen were able to catch high target species with lower bycatch. In short, experienced fishermen can avoid catching dolphins, seabirds, sharks and other bycatch species.

Bycatch shark
Sharks can still be caught as bycatch.
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It was surprisingly difficult to test the managers’ assumptions with data. So how did we show this?

Fishing ability is known to vary. As a result, some fishermen and boats are consistently more profitable. If fishermen have varying skills in catching their target species, it follows that they have varying skills in avoiding bycatch species.

The pattern of varying skills had never been tested against bycatch figures. In part, that’s because we need a lot of data to isolate individual behaviors and skills from many other factors influencing bycatch. Fishermen, for example, often link high bycatch to environmental factors, such as specific fishing grounds or breeding seasons.



Read more: There aren’t enough fish in the sea, so let’s eat everything we catch


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

We found a clear signal in the data. In general, individual vessels caused more differences in bycatch than fishing location, season or year. In each of the five fisheries, we found high-performing operators who could consistently achieve high target catches and low bycatch, as well as low-performing operators that did the opposite. This even applies to fishing gear known worldwide for high bycatch, such as bottom trawls and gillnets.

We don’t know exactly what fishermen do to prevent bycatch. Fishing “skill” is likely to be a mix of experience and environmental knowledge, the ability to effectively lead a crew, operate and maintain equipment, and respond quickly to changing sea conditions. These nuanced behaviors are not recorded in logbooks and are difficult to describe, meaning we have to work directly with fishermen to really untangle the vessel effect.

Can we retrain our fishermen?

Now that we know that the skills of our fishermen are so important, we have the opportunity to keep bycatch even lower than thought possible. We can challenge the belief that bycatch is an unavoidable part of fishing.

Harnessing the skills and knowledge of high-quality fishermen can motivate behavior change in ways that are more likely to succeed than top-down regulation or new technologies.

We can look at incentives to encourage skilled and experienced fishermen to spread their knowledge and skills. This would raise the bar for underperforming fishermen and help the industry avoid penalties for the actions of some very damaging boats.

Working closely with high-quality fishermen, we could see even more innovation in bycatch cutting, as well as other long-standing issues such as waste management and abandoned “ghost nets” that can continue to kill for years.

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