The Salmon bycatch mystery

We’ve all heard the theories about high-seas exploitation of wild Atlantic salmon, from boats ‘not at sea’ during the Covid pandemic leading to better salmon returns, to trawlers scooping up wild salmon on the high seas.

But when it comes to hard evidence, there’s not a lot to go on. The degree to which wild salmon post-smolts and adults are being intercepted at sea, purposefully or as bycatch, is a glaring knowledge gap. While conservationists work hard to get freshwater catchments producing as many fit and healthy smolts as possible in an environment of cold, clean water, they’re also pushing on governments to do much better for wild salmon at sea. This message came through loud and clear at the Missing Salmon Alliance’s Wild Salmon Connections conference held in London earlier this year.

What do we know, and what don’t we know, about bycatch?

Important research by the Game & Wildlife Conservation Trust has confirmed that wild salmon and sea-trout are being caught as bycatch in coastal gillnets in the English Channel. Further work by Missing Salmon Alliance researchers to gather and organise PIT (Passive Integrated Transponder) tagging data from salmon rivers across Europe and North America, enabled the identification of two French salmon smolts from the rivers Scorff and Bresle to be identified by a PIT tag detector in an Icelandic fish processing plant in 2023.

However, the question is: to what degree is bycatch happening on the high seas which could impact wild salmon at a larger population level?

The lack of oversight

At the London event, Dr Sophie Elliott of the Game & Wildlife Conservation Trust laid out some of the challenges facing us when it comes to filling this important knowledge gap. Only around 2% of commercial fishing vessels from the UK and Europe have scientific observers on board to monitor species caught as bycatch, with most of these vessels being ‘demersal’ operators, fishing on the seabed with methods such as bottom trawling, rather than ‘pelagic’ operators more likely to encounter migrating wild salmon. In reality, the number is less than 2%.

“There’s clearly under-reporting going on,” said
Dr Elliott, who referenced an example relating to the critically endangered European sturgeon. From 2003-2021, only 11 reports of sturgeon bycatch at sea were logged by French fisheries observers. However, within a dedicated project set up to look at sturgeon bycatch, with fishermen themselves asked to self-report, over 300 sturgeon were logged between 2012-2021.

Dr Elliott went on to highlight further shortcomings when it came to on-shore observers (checking for bycatch in fish markets), the underreporting of bycatch in vessel logbooks, as well as scientific studies that are overwhelmingly focused on bycatch in demersal fisheries rather than those where Atlantic salmon could be expected.

Where are vessels fishing and when?

So, in the absence of any real evidence, we’re left having to piece together other parts of the puzzle.  A study that involved ICES (International Council for the Exploration of the Sea) researchers, working within the Working Group on North Atlantic Salmon (WGNAS), was shown. This used pelagic fisheries landings data combined with smolt migration pathways to understand bycatch risk. Herring and mackerel fishing activity presented the highest risk, with potential cumulative impacts as post-smolts migrate north to their feeding grounds.

With freely available AIS (Automatic Identification System) vessel data, Dr Elliott also presented a visualisation of trawlers and gillnetters operating to the north of the British Isles in the same areas where salmon post-smolts are transiting.

Nonetheless, Dr Elliott noted that although some vessels can catch up to 250 tonnes in a single haul, the identification of salmon post-smolts would be nigh-on impossible as only a handful of hauls are even examined for bycatch. There is clearly a significant risk here it seems, but still nothing concrete to go on.

How Europe compares with North America

The comparison made by Dr Elliott between the level of salmonid bycatch monitoring in the Pacific for chinook salmon, versus the Atlantic, was stark. Compared to the 2% of vessels monitored for bycatch in the UK and Europe, in the US (including Alaska) and Canada, 50% of semi-pelagic hake vessels are monitored, while 100% of demersal vessels are monitored by either video or on-board observers. In the Pacific a widespread genetic sampling programme looks to identify evidence of salmonids in hauls, while there is no such programme in Europe, despite the fact that declines in Atlantic salmon have been observed for longer than that of chinook salmon.

Hannah Rudd from the Angling Trust followed Dr Elliott, and echoed the urgent need for better monitoring, stronger precautionary management, and the importance of wild salmonids being recognised as a marine species, as well as a freshwater one. Like Dr Elliott, Rudd drew attention to the lack of consideration for salmonids in marine planning. Of the 377 Marine Protected Areas (MPAs) in the UK, none are designated for wild salmon and sea-trout. Indeed, many still permit gillnetting and bottom trawling. In Rudd’s words, they’re more like ‘marine unprotected areas’.

So what about legislation?

What commitments must governments adhere to? Dr Tom Appleby from the Blue Marine Foundation wrapped up the bycatch section of the conference, and spoke of the international legal duties relating to salmon bycatch. The Bern Convention signed in 1979, the forerunner to the EU Habitats Directive, required there to be “appropriate legislative and administrative measures to ensure the protection of wild salmon”. The Habitats Directive itself however, which is translated in UK law by Habitats Regulations and still effectively applies in the UK post-Brexit, only protects wild salmon in freshwater SACs (Special Areas of Conservation). “You’ve got a crazy situation where the thing is protected for only part of its lifecycle,” remarked Dr Appleby, who then listed a raft of other legal obligations, before concluding that these are messy, overlapping, and with huge gaps in data that prevent action on fulfilling legal responsibilities.
“We have enough legislation,” he said, “we just need to apply it.”

Filling the knowledge gap

Governments who say they’re serious about saving endangered wild Atlantic salmon must step up. This is a matter of political will. It can’t always be left to the charitable sector – this task needs a national and even international approach, ensuring that wild salmon are also recognised as a marine fish, that bycatch monitoring is actually looking out for them, that onboard and onshore monitoring is increased, and that technologies like DNA and genetic analysis are put to use. This would mean going some way to fulfilling the existing legal obligations and doing better for wild salmon and sea-trout.

At the end of the Wild Salmon Connections conference, the Missing Salmon Alliance released a new set of policy asks for England and Scotland, both of which demand that policymakers urgently do more to understand bycatch and the role it may be playing in wild salmon decline, details of which can be found on the Missing Salmon Alliance website (missingsalmonalliance.org). Readers can also go there to view the event’s recorded presentations
in full, including those of Dr Elliott, Hannah Rudd and Dr Appleby.

So, for now at least, the knowledge gap remains; however, filling it is increasingly in the sights of conservation groups and their advocacy strategies.

It’s time the theories were either proven wrong, or right, and that the work is done to properly understand how significant a role bycatch is playing in wild salmon decline.