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
After a two-year tour of UK art galleries, community spaces and aquariums, the Shark Trust’s acclaimed Oceanic31 exhibition takes its final bow at the Royal Geographical Society later this month. And the unique collection of artwork, depicting 31 species of oceanic sharks and rays, donated by 31 artists, is now open for bids from art lovers and shark enthusiasts. The online auction, launched today, will close on the 7th December at 8pm (BST). The money raised will support the Shark Trust Oceanics Programme.
People can now bid on 27 of the artworks by visiting this website:
https://superstars-auctions.com/sharktrustauction
It is a chance to own a beautiful piece of original art and to support the Shark Trust. The timing of the auction also means that these would make a very special Christmas gift for any shark-lover.
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- Bigeye Thresher Shark by Janina Rossiter
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- Carcharodon carcharias by Jimmy Higgs
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- Croc VR 2030 by Tom Mead
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- Oceanic Whitetip by ATM
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- Silky Street by ScapaJoe
The diversity of pieces mirrors that of the sharks and rays they represent. You can bid on paintings, digital creations, sculptures, mixed media and more. You can pick your favourite artist or species of shark. Or you can select the perfect artwork to make a statement in your home or office. Whichever you choose, you will be supporting the work to protect these amazing animals.
One of the pieces of art has been selected to be auctioned live by Steve Backshall at the For the Love of Sharks event at the Royal Geographical Society in London on the 29th November. In addition to this, two further pieces will be raffled at this event, giving people a chance to win an incredible piece of shark art. For the Love of Sharks is the Shark Trust’s flagship evening. A night to celebrate sharks. Steve Backshall is the headline speaker at this event that will see other prominent shark advocates join him on stage.
Tickets for the event can be snapped up here:
https://thesharktrust.org.uk/Event/flos24
Those that would like to see the Oceanic 31 exhibition have one final chance. It is being displayed at the Pavilion at the Royal Geographic Society from 26th November until the 7th December. Entry is free.
Find out more here:
https://www.rgs.org/events/upcoming-events/oceanic-31
Paul Cox, Shark Trust CEO, Said “This exhibition has given us the opportunity to reach out to a new audience. And inspire more people with the wonderful sharks and rays on which our Big Shark Pledge campaign is based. We are immensely grateful to the 31 artists who have worked so hard to create these works.”
Bid for your favourite Oceanic 31 artwork here:
https://superstars-auctions.com/sharktrustauction
Banner Image: Smooth Hammerhead by Alicia Hayden
Until 28 November, prizes worth a massive £10,000 – including experiences, products and tuition – feature in a line-up of items that can be won for £5 in an online prize draw to celebrate Bite-Back Shark & Marine Conservation’s 20th anniversary and help generate crucial funds for the future.
Top of the list of prizes is the chance to spend time with adventurer and wildlife expert Steve Backshall, a workout session with Nat Geo star Aldo Kane, a kayaking trip alongside white-water expert and diver Sal Montgomery and a Zoom call with ‘shark whisperer’ Cristina Zenato.
On top of that, some of the most admired companies in the diving and scuba industry have been quick to support the charity with fabulous prizes that make the £5 ticket price worth more than just a flutter.
Master Liveaboards, BSAC, Midlands Diving Chamber, Go Freediving and Blue Shark Snorkel have all generously donated experience prizes, while celebrated photographer Alex Mustard has donated a print and artists Scott Gleed and Olivier Leger have donated a sculpture and illustration to help boost the fundraising pot.
Fourth Element has donated Ocean Positive gear and LA watch company Nodus has gifted the charity a stunning dive watch. For land lovers, the charity has included a five star London hotel stay at Bankside Hotel plus a family visit to Longleat Safari Park in the roster of prizes.
Campaign director for Bite-Back, Graham Buckingham, said: “We’ve been overwhelmed with support from companies and individuals that we truly admire and who have supported us on our 20 year journey and we’re truly grateful to them all. While we feel incredibly proud of our achievements over the past two decades – and we are super excited about the next chapter – this prize draw isn’t a vanity project. It represents a real lifeline to our work and important advancements in the global protection of sharks. So we hope divers, dive clubs and even bargain hunters grab some tickets to make this a massive success.”
The charity hopes that the prize draw will generate crucial funds to launch a brand new, ground-breaking, campaign to enrol the public and increase support for the protection of sharks around the world.
To enter the competition visit www.bite-back.com/prizedraw. The prize winners will be announced on 1 December 2024.
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