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Irish Times
05-07-2025
- Science
- Irish Times
Jaws at 50: the most significant piece of negative publicity sharks have ever received
The theme music alone of the classic film Jaws is scary but the dramatic footage of the giant fish itself, albeit a mechanical model, would be enough to give anyone nightmares. It is hard to believe that this iconic movie is half a century old this year but it is probably the most significant piece of negative publicity that sharks have ever received. Ask anyone you know what they think about sharks and the reply is rarely positive. The movie was based loosely on Peter Benchley's novel Jaws which describes a renegade great white shark on the east coast of the United States. Previously unknown in Irish waters, there are now confirmed records of this species as far north as the Bay of Biscay but reports around Ireland and the UK are confined to anecdotal sightings. Ireland is a globally recognised hotspot for other shark species, such as the basking shark, porbeagle and tope shark, but great whites have yet to be formally recorded here. Found throughout the world's oceans, great white sharks were historically common throughout the Mediterranean before overfishing caused major declines. In 2024, a team of scientists embarked on a major survey with the goal of documenting the presence of the great white shark in Irish waters. Dr Nick Payne of Trinity College Dublin, who led the expedition, said he was optimistic about the team's chances of confirming its presence off the Irish coast. I have never seen a great white shark but I have had an encounter with the largest fish in the Atlantic Ocean. I was sailing off the coast of Mayo when a pair of fins appeared in the water beside the boat, moving slowly on the surface. As the fins came closer, I realised that they were both part of the same animal, a basking shark. It moved sinuously across the sea with a large open mouth capturing the rich harvest of plankton. Basking sharks were once plentiful around the Irish coastline, migrating into our waters in summer and disappearing in the winter. The location of my sighting was not far from Keem Bay at the very western tip of Achill Island. This is a cliff-bound cove with a beautiful sandy beach at its head. Throughout the early 20th century this was the location for the capture and killing of basking sharks and large quantities of the valuable shark oil were exported to England. [ Eye on Nature: If bees can't see red, why is one drawn to this red poppy? Opens in new window ] A shortage of fuel after second World War led to an increasing market for shark oil for use in certain industrial products. The slow-moving basking sharks swam into the bay to feed on dense swarms of plankton near the sea surface. Here they became entangled in nets set by the islanders who then launched their lightweight curraghs and killed the struggling fish, stabbing them with scythe blades attached to long poles. Over a 30-year period up to the 1970s more than 12,000 basking sharks were landed on Achill – an average of at least 400 fish per year. Not surprisingly, catches declined markedly towards the end of this period and, with the availability of alternative mineral oils, the market for shark oil disappeared, allowing the few remaining animals to survive. Today, basking sharks are back, their population slowly recovering from this classic example of overfishing. READ MORE Other shark species are not immune from the pressures of overfishing either. These species fill ecological niches that are important in maintaining a balance within the ecosystem. Their removal can result in cascading effects that have a negative effect on marine biodiversity right down through the food chain. Irish waters are known to contain 71 cartilaginous fish species (sharks and rays), over half of the European list. Of these, 58 were assessed using the latest international categories in the Irish Red List. Six species were considered to be critically endangered – Portuguese dogfish, common (blue) skate, flapper skate, porbeagle shark, white skate and angel shark. For example, numbers of angel sharks recorded in tagging programmes show a decline of over 90 per cent since the 1980s. A further five species were assessed as endangered while six more species were rated as vulnerable. Sharks tend to grow slowly and produce small numbers of young each year, which can make them particularly vulnerable. [ How plans for new Guggenheim museum have triggered major biodiversity row in Spain Opens in new window ] While there are no longer any vessels fishing commercially for threatened cartilaginous fish in Irish waters, some are taken as by-catch in other fisheries, involving both Irish and non-Irish boats. Ireland is not unique in this as, since 1970, the global abundance of sharks and rays has declined by 71 per cent owing to an 18-fold increase in relative fishing pressure. Sharks could use some good PR to encourage better protection and recovery of the threatened species. Richard Nairn is an ecologist and writer. His latest book is Future Wild: Nature Restoration in Ireland .
Irish Times
28-06-2025
- General
- Irish Times
Wild salmon are on the brink of disappearing from Irish waters
It's difficult to grasp two truths when only one is in plain sight. Take a walk down the chilled section of any supermarket and you'll spot rows upon rows of Atlantic salmon for sale. Whether it's fresh, poached, smoked over peat or skinless, canned, in pots flavoured with lemon and herbs, or ready-made sushi rolls wrapped in rice, farmed salmon might not be cheap, but it's abundant, in high demand (Irish production has risen by 51 per cent in the past few years) and everywhere. The other reality, underwater and hidden from our view, couldn't be more different. In the past five decades, wild salmon numbers in Irish waters have dropped by 90 per cent – and that's from an already low level in the 1970s. They are now on the brink of disappearing. Earlier this month, scientists from Nasco, an international body set up in 1984 to protect these iconic fish, met in Cardiff. Known for their cautious, measured tone, the boffins' latest warning is anything but: wild Atlantic salmon are in crisis , and only 'urgent and transformative' action can save them. Wild salmon are born in freshwater, travel to the sea, and then return to their birthplace to spawn, making them a clear sign of how well we're managing to coexist with other life. They need cold, clean and free-flowing waters, but right now we're offering rivers and oceans that are too warm, polluted, exploited or physically altered, making life impossible for these fish. On top of that, many rivers are blocked by man-made structures like weirs, culverts and dams, preventing salmon from completing their journey. READ MORE Nasco scientists say that salmon farming is a significant threat . Along Ireland's west coast – from Donegal to Mayo to Cork – tens of thousands of salmon are raised in circular open-net cages that float just offshore. For sea lice, the crustaceans about the length of a small button that feed on salmon, these pens are like a giant seafood banquet. The lice attach themselves to the fish using their clawed limbs, then crawl across their skin, feeding on them and eventually eating through to the muscle and fat before releasing eggs into the surrounding waters. Without treatment, an infested farmed salmon won't survive long. For young wild salmon leaving their home river for the first time, the journey to sea is full of danger. A female adult salmon lays thousands of eggs, but only a few will survive to become adults. As the young salmon swim by the salmon farms along the coast out into the Atlantic, they can pick up sea lice. These parasites can cause serious harm; scientists say it only takes a few lice to kill a young wild salmon. However, some experts sharply disagree over how much blame sea lice from fish farms deserve for the decline in young wild salmon. This debate really matters because, by law, every fish farm must have an aquaculture licence to operate. The rules are clear: if the science raises any reasonable question that sea lice from a farm could cause serious damage to wild salmon, then granting a licence becomes very difficult for the authorities to justify. 'Unless a salmon conservation programme is initiated, Ireland could be looking at a situation where we will have little or no salmon left in the wild,' according to Declan Cooke of Inland Fisheries Ireland Scientists can use a simple method to determine how sea lice affect wild salmon. They take two groups of young salmon; one group is given a special chemical treatment to protect them from lice; the other is left untreated. Both groups are then released into the same river, go to sea and face the same conditions. A year later, researchers count how many fish from each group return. If more of the treated salmon come back than the untreated ones, it shows that sea lice have a serious impact. Between 2001 and 2009, scientists from the Marine Institute carried out this 'paired release' research at eight sites in Ireland. Their conclusions, published in 2013: while sea lice cause a 'significant' number of deaths among young wild salmon, the overall impact is 'minor and irregular'. This paper has been used to support the granting of fish farm licences as evidence that sea lice from farms aren't a significant threat to wild salmon survival. [ Wild salmon are an Irish icon. Now they're almost gone Opens in new window ] Not everyone agrees. Scientists from Canada, Norway and the UK raised serious concerns about the paper and, last month, researchers from Inland Fisheries Ireland published a new study looking at 18 years' worth of data from paired released experiments. They found that, on average, an 18 per cent drop in survival among young salmon that weren't treated for lice, and the more lice on the farms, the greater the losses. Their conclusion is clear: sea lice from salmon farms pose a real threat to wild salmon. Why does this matter? Because 12 rivers along Ireland's west coast flow into legally protected areas where salmon farms operate. If scientists are now saying that these farms are killing young wild salmon due to sea lice infestations, then the law leaves little room for inaction. Authorities are obliged to act to move the farms to new locations, revoke their licences or find a way to ensure that there are no lice on the farmed salmon during the critical time when the young wild salmon are heading out to sea. There is no single solution that will save Ireland's wild salmon. If emissions remain high, our waters will continue to heat up. But not everything is hopeless – there are things in our immediate control. We can remove our barriers, free our waters from pollution and, if the science shows it will help wild stocks survive, change how or where salmon farms operate. Holding on to the reality of wild salmon in our waterways is one we should cling to – for future generations if nothing else.
