Latest news with #scientists
Irish Times
2 hours ago
- 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.
Yahoo
5 hours ago
- Science
- Yahoo
Earth's Rotation Is Speeding up This Summer—but Just for 3 Days
Here's what you'll learn when you read this story: Although the Earth completes one full rotation in 86,400 seconds on average, that spin fluctuates by a millisecond or two every day. Before 2020, the Earth never experienced a day shorter than the average by much more than a millisecond, but in the past five years, it's been more likely to see days during the summer than are nearly half-a-millisecond shorter than pre-2020s levels. In 2025, the Earth will continue this trend, and scientists predict that three days—July 9, July 22, and August 5—could be atypically short compared to historical averages. While many of the astronomical truths of existence feel like immutable facts compared to our relatively puny lifespans, the movement of the heavens is constantly changing and evolving. Take the Earth's rotation, for example. During the Mesozoic, dinosaurs actually experienced 23 hours days, and as early as the Bronze Age, the average day was 0.47 seconds shorter. 200 million years from now, a standard Earth day will actually be 25 hours long (and it remains to be seen whether or not humans will still complain about there not being enough hours in the day). While the Earth's rotation changes over cosmic timescales, it also fluctuates on daily ones. We all know that a day lasts 24 hours, or 86,400 seconds, but that's not perfectly accurate. Earthquakes, volcanoes, tidal forces, subterranean geology, and many other mechanisms can cause the planet's rotation to slow down or speed up, and those micro-adjustments can trend over time. Although Earth's overall rotational trend is to slow down, since 2020, scientists have noticed—thanks to the International Earth Rotation and Reference Systems Service (IERS) at the U.S. Naval Observatory in Washington D.C.—that Earth's rotation is speeding up. So much so, in fact, that experts expect we'll need to subtract a leap second for the first time ever in 2029. A new report from claims that this fast-rotating trend won't be slowing down in 2025, either. According to IERS data, the three shortest days (mathematically speaking) this year will be July 9, July 22, and August 5. These are the dates when the Moon will be furthest from the equator, which will impact the speed of Earth's rotation. Current predictions place the shortest day, August 5, at roughly 1.51 milliseconds shorter than average. That doesn't quite beat out the recent record holder—July 5, 2024, which clocked in at 1.66 milliseconds shorter than average—but it's still a full half-millisecond faster than when this rotational trend began in 2020 (and, technically, it could still break the record once scientists measure the actual rotation on the day). 'Nobody expected this,' Leonid Zotov, an Earth rotation expert from Moscow State University, told Zotov co-authored a study in 2022 analyzing the cause of Earth's recent rotational uptick. 'The cause of this acceleration is not explained […]. Most scientists believe it is something inside the Earth. Ocean and atmospheric models don't explain this huge acceleration.' Scientists will continue to study the reasons behind the Earth's rotational fluctuation, and we'll all endure at least one leap second skip before abandoning leap seconds completely by 2035. However, Zotov also tells that this acceleration is not a new trend. In other words, we're not traveling back toward back toward the Mesozoic in terms of rotation. The planet will eventually continue its steady deceleration—this is, of course, it's natural tendency, but surface changes like polar ice melt can also contribute to the Earth's rotation slowing down. The only constant is change. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
The National
12 hours ago
- Science
- The National
Pictures of the week: From a mosque in Oman to a mangrove in Indonesia
• Scientists estimate there could be as many as 3 million fungal species globally • Only about 160,000 have been officially described leaving around 90% undiscovered • Fungi account for roughly 90% of Earth's unknown biodiversity • Forest fungi help tackle climate change, absorbing up to 36% of global fossil fuel emissions annually and storing around 5 billion tonnes of carbon in the planet's topsoil
Telegraph
14 hours ago
- Health
- Telegraph
Why cats prefer sleeping on their left side
Cats prefer to sleep on their left side to protect themselves from predators, a study has found. The pets sleep for up to 16 hours a day and often curl up or stretch out for a snooze in opportune places. But the way the animal settles down is not random, and there is an evolutionarily hard-wired logic underpinning it, according to a study from the Ruhr University Bochum in Germany. Scientists found cats lie on their left side around two-thirds of the time, which shows that it was done deliberately. They looked at clips on YouTube of more than 400 sleeping cats and logged which side they were sleeping on. Data revealed that 266 of the cats (66.5 per cent) were on their left side, leaving scientists to conclude this was a survival trait from their history in the wild. Sleeping on their left side means when they wake, their left eye is able to see the local area unobstructed by the cat's own body. This visual information is then processed by the right side of the brain. This hemisphere is what processes threats and is responsible for escaping danger as well as knowing an individual animal's position. This puts the cat at an advantage compared to if it was to sleep on its right side – when the information is processed by the left side of the brain, which is less specialised to aid a swift escape. Anti-predator vigilance This leftward preference is just one of the many ways in which cats protect themselves. 'Sleep is one of the most vulnerable states for an animal, as anti-predator vigilance is drastically reduced, especially in deep sleeping phases,' according to the study. 'Domestic cats are both predators and prey (e.g. for coyotes) and sleep an average of 12–16 hours a day. 'Therefore, they spend almost 60-65% of their lifetime in a highly vulnerable state. To reduce predation risks, cats prefer to rest in elevated positions so that predators are more visible to them and the cats, in turn, are more visually concealed from predators. 'In such a spot, predators can access cats only from below. Thus, their preference for resting in an elevated position can provide comfort, safety, and a clear vantage point for monitoring their environments. 'We hypothesised that a lateralised sleeping position further increases the chances of quickly detecting predators (or to identify careless prey) when awoken.' Threat-processing leftward bias Pregnant cows are known to prefer their left side while sleeping for a similar reason, experts believe. The scientists also found that the pawedness of a cat, whether it preferred its left or right side, is likely not to blame for the sleeping preference. A 2017 study found that male cats tend to prefer their left paws and females are more right-paw dominant. 'We are inclined to believe that the significant leftward bias in sleeping position in cats may have been evolutionarily driven by hemispheric asymmetries of threat processing,' the scientists add in their paper, published in the journal Current Biology.
The Independent
18 hours ago
- Science
- The Independent
Why our chins remain an evolutionary mystery
Scientists are still trying to understand the evolutionary reasons behind unique human features, such as the chin and the relative size of testicles. The concept of convergent evolution, where a feature evolves multiple times independently, serves as a natural experiment to determine the purpose of body parts. Analysis of testicle size across various mammals, including monkeys, gorillas, chimps, and dolphins, reveals a consistent correlation between larger testicles and promiscuous mating behaviors. This correlation suggests that larger testicles evolved to facilitate sperm competition in species with multiple partners, with human testicle size falling in the middle. The human chin remains an evolutionary mystery because its uniqueness among mammals, including Neanderthals, prevents the use of convergent evolution to test hypotheses about its purpose.
