Marine Life & Conservation
Hatchlings’ Drift Experiences Determine Sea Turtle Migration Patterns
New research has found that adult sea-turtle migrations and their selection of feeding sites are directly influenced by their past experiences as little hatchlings adrift in ocean currents.
When they breed, adult sea turtles return to the beach where they were born. After breeding, adult sea turtles typically migrate several hundreds to thousands of kilometres to their feeding habitats. However, there has been little information about how turtles chose their feeding sites. For example, some turtles migrate to feeding habitats thousands of kilometres away, while other turtles don’t migrate or feed in the open ocean.
The study, which involves the University of Southampton, looked at what habitats the turtles would have experienced as juveniles. New-born hatchling sea turtles are too small to track with satellite tags. However, when they emerge from their eggs, they head to the ocean and drift with ocean currents to their juvenile development habitats. The researchers combined all the available satellite tracking data on adult turtles with models of how the world’s sea water moves past nesting sites to study where the hatchling sea turtles drift to.
By comparing global patterns in the migrations of all satellite tracked sea turtles with global hatchling drift patterns, they showed that adult sea turtle migrations and foraging habitat selections were based on their past experiences drifting with ocean currents.
Dr Rebecca Scott, who led the study soon to be reported in the journal Ecology, says: “Hatchlings’ swimming abilities are pretty weak, and so they are largely at the mercy of the currents. If they drift to a good site, they seem to imprint on this location, and then later actively go there as an adult; and because they’re bigger and stronger they can swim there directly.
“Conversely, if the hatchlings don’t drift to sites that are suitable for adult feeding, you see that reflected in the behaviour of the adults, which either do not migrate or they feed in the open ocean, which is not the normal strategy for most turtle species,” explained Dr Scott, who is based at the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany.
Many animal groups undertake great migrations, and the process of learning where to go on these travels can take several forms. For example, some juvenile whales and birds learn migration routes by following their mothers or more experienced group members, whilst other bird and insect species seem to be born with the information or a map sense that informs them where they should migrate.
However, neither of these strategies works for turtles. Once the adult female has laid her eggs on a beach, her involvement in her offspring’s development ends. When the hatchlings crawl down the beach into the water, they are on their own; there is no experienced turtle to follow, and they go where the ocean takes them.
Dr Bob Marsh from the University of Southampton, who was Dr Scott’s supervisor and co-author of the study, said: “Although it is known that ocean currents have a large influence on the dispersion of small planktonic organisms, these findings reveal ocean currents also directly shape some the migrations of some of the largest, most powerful long distance migrants in the animal kingdom.”
Source: www.southampton.ac.uk
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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