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Marine Life & Conservation

Great white sharks can ‘live for 70 years’, new study claims

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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

Scubaverse meet the Ullapool Sea Savers

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On a recent trip to the Highlands of Scotland we met up with an amazing bunch of ocean conservationists called the Ullapool Sea Savers. They are a passionate group of young people based in the beautiful coastal town of Ullapool who are working to protect the marine environment around them and it was a real pleasure to hear their ideas and to witness just how committed they are to their cause.

They are a group run by kids for kids, in response to the inspirational work of local marine campaigner Noel Hawkins. Their core premise is that people will protect what they love and they aim to show people just how much there is to love about the sea. The Ullapool Sea Savers keep things positive and work to inspire those around them and each other.

Each Sea Saver is a Species Champion, and they nominate their preferred species, learn all about them and then present a “fact fie” to the rest of the group. This ties in with the Species Champion Initiative launched by Scottish Environment LINK which asks Members of the Scottish Parliament (MSPs) to lend political support to the protection of Scotland’s threatened wildlife by becoming ‘Species Champions’. This has led to some great support from MSPs when it comes to campaigning, such as Maree Todd MSP and Minister for Children and Young People (who is also from Ullapool which helped!) becoming the Flameshell Species Champion and working closely with Caillin who is Flameshell Ambassador for the Ullapool Sea Savers. Similarly, Gail Ross MSP for our region, took on the role of Seagrass Species Champion and helped USS campaign against plans to allow Mechanical Kelp Extraction (Dredging!) to be given the go ahead in Scotland. There are plenty more example of this great partnering scheme here.

On top of this, the Ullapool Sea Savers have formed pods, and each small group selects a local campaign to work on, with the “New Wave” working on a “Drain Campaign” to educate people that litter dropped on the street ends up in the surrounding sea. They recently surveyed the litter by the first drain in the campaign and found over 300 cigarette butts that would have all washed out to sea during the next rainfall.

The “Blue Starfish” are working on a crisp packet recycling campaign, starting at the local school with hopes to widen the scale going forward. There is now also the newly formed Seal Pups Pod and we look forward to seeing what campaign they decide to focus on.

Many of the group have passed qualifications in snorkeling, diving, boat handling and they are currently learning to operate an ROV that they plan to use to mark underwater litter and ghost nets so it can be retrieved by divers. The group are also regularly found litter-picking along the coastline. As a group they have a powerful voice and recently won the Sunday Mail, Young Scot Awards 2021 for the Environment Category.

The older kids mentor some of the younger ones that are new to joining the group and what really struck us on meeting the group was how keen they were to pass on their wealth of knowledge and their passion for ocean conservation. We chatted to them about what we do and told them about some of our favourite marine life encounters from around the world. I hope we inspired them just a fraction as much as they inspired us! 

To find out more about the Ullapool Sea Savers you can visit their website by clicking here.

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Marine Life & Conservation

Discover Whale Sharks in the Galapagos tomorrow with Regaldive

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Regaldive are inviting divers to join them next Wednesday for a virtual tour of the Galapagos Islands.  Marine biologist Sofía Green will give an insight into her incredible encounters with Whale Sharks.

An expert on Whale Shark behaviour, Sofía has been part of the Galapagos Whale Shark Project since 2017 and is at the forefront of global Whale Shark research. She will also be leading Regaldive’s exclusive Whale Shark Expedition in September 2022, timed to visit during prime Whale Shark season. Founder of the Galapagos Whale Shark Project, Jonathan Green, will also be joining the Zoom event taking questions so do join them to find out more.

  • Date: Wednesday, 16 June
  • Timings: 7-8 pm (UK time)

Register via email here to book your place and let the team know if you have any questions you would like to ask Sofia and Jonathan.

www.regaldive.co.uk

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Explore the amazing triangle of Red Sea Reefs - The Brothers, Daedalus and Elphinstone on board the brand new liveaboard Big Blue.  With an option to add on a week at Roots Red Sea before or after. 

Strong currents and deep blue water are the catalysts that bring the pelagic species flocking to these reefs. The reefs themselves provide exquisite homes for a multitude of marine life.  The wafting soft corals are adorned with thousands of colourful fish. The gorgonian fans and hard corals provide magnificent back drops, all being patrolled by the reef’s predatory species.

£1475 per person based on double occupancy.  Soft all inclusive board basis, buffet meals with snacks, tea and coffee always available.  Add a week on at Roots Red Sea Resort before or after the liveaboard for just £725pp.  Flights and transfers are included.  See our brochure linked above for the full itinerary.

This trip will be hosted by The Scuba Place.  Come Dive with Us!

Call 020 3515 9955 or email john@thescubaplace.co.uk

www.thescubaplace.co.uk

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