Marine Life & Conservation
Great white sharks can ‘live for 70 years’, new study claims
Great white sharks live far longer than was previously thought.
Using a new technique to age the tissues of these impressive creatures, scientists have identified a male great white that lived into its 70s.
The researchers say the finding has important implications for the animals’ protection.
Knowing the longevity of a species, how fast it grows and when it reaches sexual maturity is vital information for designing conservation programmes.
“These creatures are amazing and it’s fascinating to study them,” said Li Ling Hamady, who is part of a joint programme between MIT and the Woods Hole Oceanographic Institution in the US.
“Everyone thinks they know these animals so well, and the public perception is that they’re either loved or hated. But in terms of the science, we’re only just now beginning to understand what they eat, where they go and how long they live.”
Scientists have tried to age the spectacular predators by counting annual growth rings in their tissues, such as in their vertebrae. But the sharks’ cartilage skeleton makes the division between these rings hard to discern even under the microscope.
Now, Ms Hamady and colleagues have said that they made these rings easier to read by looking for a known radioactive marker.
This is a type, or isotope, of carbon atom that was produced in the fallout from the atmospheric nuclear bomb tests in the 1950s and 1960s.
It would have gone into the ocean and been incorporated into the tissues of marine animals living through that period. The scientists used the easy-to-detect radioactive carbon as a kind of date stamp to help them count and calibrate the growth layers better and thus determine the age of their test samples.
“I always think the vertebrae are remarkably small for such a big animal,” explained Ms Hamady.
“Also, as they get older and larger, the sharks either stop laying down material or the layers become so thin they’re really difficult to see. It’s very fine work. I’m using a microscope and a razor and even then it’s hard to get annual resolution.”
Previous studies on Indian and Pacific Ocean animals – not using the A-bomb marker approach – had suggested great whites were certainly capable of living into their twenties. With the bomb markers, age estimates for the MIT-WHOI animals were up to 73 years old for the largest male in the study, and 40 years old for the largest female.
All these animals came from the Atlantic, but the researchers do not think there are any significant differences between the lifespans of the sharks living in the three big ocean basins.
Assuming they do live into the 70s in a normal lifetime, white sharks may now be considered among the longest-lived of all cartilaginous fish.
These icons of the sea have suffered some bad press down the years, very often unfairly, and like many of the world’s sharks have come under increased hunting pressure.
According to the IUCN list of threatened species, great whites are considered “vulnerable”.
But if, as now seems likely, they are slower growing and later to mature than was previously recognised, it means also that great whites would find it harder to recover their numbers if populations are depressed because of fishing, environmental and other pressures.
Ian Fergusson, a founding patron of the Shark Trust, commented: “White sharks have a fairly low fecundity in terms of litter size. Typically, females might have a handful of pups per litter, and we’re not sure how often they even get pregnant in a lifetime.
“It puts a spotlight on the need for the conservation of white sharks to be considered on a par with the conservation we have – and take for granted – for marine mammals, which also have low fecundity, long lifespans and late maturity. The conservation of sharks is not like the conservation of trout in a river, and that’s something people in the fisheries business don’t always understand.”
Source: www.bbc.co.uk/news
Photo: Greg Skomal / MA Marine Fisheries
Marine Life & Conservation
Paul Watson Released as Denmark Blocks Japan’s Extradition Bid
Renowned anti-whaling activist Paul Watson has been released from custody in Greenland after spending five months in detention. Denmark’s Justice Ministry rejected Japan’s request for his extradition, citing insufficient guarantees that his time already served in custody would be credited against any potential sentence.
The 74-year-old Canadian-American was arrested on July 21 in Nuuk, Greenland’s capital, when his ship docked to refuel. His arrest was based on a 2012 Japanese warrant related to a 2010 encounter in Antarctic waters. Japan alleged Watson obstructed operations and caused damage to a whaling research ship during efforts to disrupt illegal whaling. Watson has consistently denied these claims, maintaining his commitment to marine conservation.
Denmark, which oversees extradition matters for Greenland, concluded that while the legal conditions for extradition were met, the lack of assurances from Japan regarding time-served credit made extradition untenable.
In a video shared by his foundation, Watson expressed gratitude and relief, saying, “After five months, it’s good to be out… and good to know they’re not sending me to Japan.” He added that the most difficult part of his time in custody was being separated from his two young sons.
Watson is a pioneering figure in marine conservation, known for founding the Captain Paul Watson Foundation in 2022 after decades of activism with the Sea Shepherd Conservation Society. His bold efforts to defend marine life have earned him widespread support, including from celebrities and conservationists. His work has also been featured in the acclaimed reality TV series Whale Wars.
Watson’s lawyer, Jonas Christoffersen, praised the decision, stating, “We are happy and relieved that Paul Watson is now free.” He added that Watson is eager to reunite with his family and continue his vital work.
The arrest occurred while Watson’s vessel, the M/Y John Paul DeJoria, was en route to the North Pacific with a team of 26 volunteers to intercept a Japanese whaling ship. His foundation described the arrest as politically motivated and emphasized that Watson’s actions were focused on ending illegal whaling practices.
Japan resumed commercial whaling in 2019 after leaving the International Whaling Commission, asserting that whale meat is a cultural tradition. Conservationists, however, continue to challenge these practices, highlighting their impact on marine ecosystems.
Despite the challenges, Watson remains steadfast in his mission to protect marine life and bring attention to whaling practices. His dedication to ocean conservation has made him a globally respected advocate for the environment.
Marine Life & Conservation
12 Days of Zero-Waste Fish-mas
This holiday period, the Marine Conservation Society, the UK’s leading ocean membership charity, invites you to make some simple changes to eating fish this Christmas to help our seas.
Dr Kenneth Bodles, Head of Fisheries and Aquaculture at the Marine Conservation Society, said, “During the festive season, our consumption increases, but so does waste. Sustainability isn’t just about where food comes from – it’s also about how you use it. By reducing waste and making the most out of your seafood, you’re not only taking steps to be more ocean-friendly, but can also help to cut costs during what is often one of the most expensive times of the year”.
The Marine Conservation Society has compiled twelve tips on how to consume seafood sustainably with zero-waste this Christmas:
Buy whole fish instead of fillets
Instead of fillets, consider buying whole fish such as salmon, hake, or lemon sole. By adopting a “nose to tail” approach with cooking, whole-baked fish not only feeds a crowd, but also helps to minimise waste and maximise sustainability by using up every part of the animal, including bones, skin, and fat.
Make fish stock
Leftover fish bones or shells can be put to good use by boiling them to make a nourishing fish stock or bisque. This can be frozen and preserved for later use and makes for a flavourful base in a soup.
Make your own fish pâté
Avoid waste by turning leftover fish, such as smoked mackerel or salmon, into a delicious pâté by blending with cream cheese and lemon. Perfect when paired with crackers.
The sustainability of salmon and mackerel varies depending on where and how it is caught or farmed. For more information on green-rated options, check the charity’s Good Fish Guide.
Buy frozen
By purchasing seafood that is frozen or vacuum-packed, this helps to reduce waste by extending the shelf life of your food.
Fish pie
If you’re wondering what to do with leftover cooked fish, why not opt for a classic fish pie with mashed potatoes, leeks, and a cheesy sauce? A sure crowd pleaser on Boxing Day.
Use the head
Don’t forget the fish head! The meat is incredibly tender and flavourful. The charity recommends a cod’s head curry or recreating Fallow’s renowned cod’s head in siracha butter.
By stretching your ingredients further, not only is this a more sustainable way to enjoy seafood, but also cost-effective by repurposing leftovers and cooking creatively.
Boxing Day brunch
Mix leftover kippers or smoked salmon with scrambled eggs for a tasty, zero-waste, Boxing Day brunch.
For best choice, make sure you buy kippers, or herring, from the North Sea and the North Irish Sea.
Zero-waste storage
A top tip from the Marine Conservation Society to avoid waste is freezing fish offcuts to save for future use.
Crisp up the skin
Even leftover fish skin can be turned into a quick savoury snack by crisping it up in an air fryer with a little olive oil and salt.
Anchovies two ways
Leftover anchovies can either be blended with butter to make a delicious anchovy butter or tossed into pasta for a hit of umami flavour.
The charity recommends opting for anchovies caught in the Bay of Biscay for best choice.
Fishcakes
For an easy, zero-waste meal, leftover seafood trimmings can be mixed with mash and fried in breadcrumbs to make fishcakes.
Pickled mussels
Try pickling mussels in 1:1 vinegar and water, with a dash of sugar for a sustainable, zero-waste snack that can be enjoyed well beyond the festive season.
Mussels farmed in the UK are a seafood superhero. Grown using low-impact methods and harvested by hand, they get all the food they need from the sea around them. This makes them one of the most sustainable, ocean-friendly, and cost-effective seafood options.
Players of People’s Postcode Lottery have raised £6.6M towards the Marine Conservation Society’s vital work in making seafood more sustainable.
Laura Chow, Head of Charities at People’s Postcode Lottery, said: “Fish is a festive favourite for many, but making sustainable choices when it comes to how we buy and eat seafood makes all the difference for our ocean. Support from players of People’s Postcode Lottery has helped the Marine Conservation Society further its sustainable seafood work, so that we can all enjoy healthier, better protected seas.”
The Marine Conservation Society encourages you to make sustainable seafood choices a year-round habit, not just for Christmas. To check how sustainable the seafood on your plate is, you can visit the charity’s Good Fish Guide. The Guide helps consumers and businesses identify the most sustainable seafood using a simple traffic light system, based on where and how species are caught or farmed. Green is the best choice, amber means improvements are needed, and red indicates fish to avoid buying.
Zero-waste gift idea
Why not embrace a zero-waste Christmas by gifting a membership to support marine conservation? It’s a meaningful, low-waste gift that helps protect our ocean for generations to come. Memberships start from as little as £5 a month – the price of a sandwich and drink from your local coffee shop.
Find the latest sustainable seafood advice for wild-caught and farmed seafood on the Good Fish Guide, downloadable to your phone from www.mcsuk.org/goodfishguide.
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