The Two Oceans Aquarium has decided to release Yoshi the loggerhead turtle back into the ocean later this year. This will be as soon as the summer months have warmed the water around Cape Point – probably some time in December 2017, explains Ingrid Sinclair.
We have already begun preparing Yoshi for release by giving her lots of exercise in the I&J Ocean Exhibit – come feeding time you might see her swimming back and forth between two targets.
Come and watch feeding time at the I&J Ocean Exhibit (12h00 and 14h00 daily) to see Yoshi’s target training
She will be fitted with a satellite tag soon and we hope to be able to track her journey for up to three years. Of course, we will share the entire process with you right here on our website.
Yoshi the Queen of the Two Oceans Aquarium
Yoshi is undoubtedly one of the Aquarium’s most famous and most loved inhabitants. She’s on first-name basis with many of our regulars, she loves swimming to the front of the exhibit to say hello to visitors, loves a good photo opportunity, and can be a bit of a bully to the other fish. In short, Yoshi has been the star of our Aquarium for many years.
We’ve all grown extremely attached to her, but all signs are there that it is time to return her to the wild. Nothing will make us happier than to see this beloved animal thrive in the open ocean, even though the farewell will be bittersweet.
Yoshi was confiscated from a boat in Table Bay Harbour by local authorities in 1996, after getting caught in a trawler’s fishing nets. When she arrived at the Aquarium, she was the size of a dinner plate and we estimate that she was about three to five years old at the time, making her between 24 and 26 now.
Why are we releasing Yoshi now?
Considering Yoshi’s age, and certain new behaviours that she is exhibiting, our curatorial team, led by Curator Maryke Musson, has decided that it’s time for Yoshi to be released.
She is within the sexual maturity range now – which is between 18 and 30 years for loggerhead turtles – and we have observed her scratching at the sand in the I&J Ocean Exhibit, possibly mimicking nest-digging behaviour that one might see in the wild. Loggerhead turtles live for between 80 and 100 years, and being confident that Yoshi is fit and healthy, there is no reason for us to keep her with us any longer.
“Did you know? Loggerhead turtles are found in oceans all across the world and can live for up to 100 years – they all outlive their turtle researchers. Their average weight is 135kg but they can range from 80 to 200kg. The heaviest loggerhead ever recorded weighed a whopping 545kg! ”
We were very encouraged by the results of a research study that showed that a captive-bred loggerhead turtle successfully returned to its birth beach after spending 10 years in captivity.
We also shared our plans with renowned South African turtle expert and author of Between the Tides – In Search of Sea Turtles (Jacana, 2012) Dr George Hughes during the decision-making process. “I am pleased to hear that Yoshi is due for release,” was Dr Hughes’ response.
“Yoshi is a splendid representative of the fact that in South Africa disinterest is not a factor that will threaten her survival. Yoshi is the embodiment of all the care and concern that South Africans, and especially the staff of the Two Oceans Aquarium, uShaka Marine World in Durban and Bayworld in Port Elizabeth, have lavished on her species when mischance has placed them in their hands. Once she is released what goes with her are our hopes that she will avoid misuse and exploitation during the long swim to her eventual feeding and nesting grounds and our wishes that her success will help contribute to the legendary survival of her kind. We wish her luck.”
Will Yoshi find her way?
Loggerhead turtles are found in oceans across the world, so we do not know where exactly Yoshi is from. Our plan, like we did with the hawksbill turtles Otto and Winston in 2015, is to release her about 30 nautical miles off Cape Point when the water is warmer, later this year. This will afford her the best chance to find her way back to her preferred location.
“Did you know? Loggerhead turtles usually dive for 15 to 30 minutes at a time but can spend up to four hours under water by holding their breath. In the wild they can swim for an average of 38km a day at an average speed of 1.6km per hour. They use currents to their advantage: they are very smart swimmers, only actively swimming for about two hours per day. ”
Scientists have been confounded as to how sea turtles like Yoshi are able to navigate the vast migratory distances that they do. It is believed that these turtles are able to detect the earth’s geomagnetic field and so determine longitude and latitude. This mechanism helps female sea turtles return to their natal beach (the beach where they hatched) so that they can lay their eggs there. We are very confident that Yoshi will return to where she’s from to carry on her lineage.
“Did you know? Loggerhead turtles breed every two to three years, they can lay eggs four to five times per breeding season and their clutches contain up to 120 eggs. Loggerheads practice “multiple paternity”: there can be up to five contributing males per clutch (which is great for genetic diversity).”
“Yoshi arrived at the Aquarium broken and lost, and it is amazing to know that we contributed to giving her that one in a 1 000 chance of reaching reproductive age,” says Two Oceans Aquarium Curator Maryke Musson. “She is an absolute legend, and has been part of our turtle conservation and rehabilitation story for many years. Through tracking the hawksbill turtles, Otto and Winston, post-release we gained confidence in knowing that our rescue turtles can continue life successfully in their natural environment. Otto swam to Madagascar, Winston swam to Gabon – I cannot wait to see where Yoshi goes!
She is ready to cross oceans. We will follow her every move as long as we get satellite transmission (hopefully for a few years), and yes, the NSRI is on standby should she need any assistance.”
What threats will Yoshi face out there?
Like all sea turtle species, loggerheads are endangered animals. Despite the deluge of eggs that they produce, only about 1 in 1 000 loggerhead turtle hatchlings survive to maturity. Natural threats to hatchling survival include predation by other animals, but we humans are posing the greatest hurdles of all: entanglement in fishing gear; poaching and illegal trade of turtle eggs, meat and shells; coastal development and habitat loss; rising sea temperatures and ocean pollution – specifically plastic – all represent the biggest factors counting against these wonderful ocean dinosaurs.
Knowing how much you love Yoshi, we know that releasing this sexually mature female adult loggerhead turtle will hopefully not only result in potentially hundreds of little Yoshis, but will also mean we have a loggerhead turtle ambassador who can help tell the story of turtles and their fight for survival all over the world.
Please share your Yoshi moments with us
We promise to keep you up to date with all Yoshi news as and when it becomes available.
In the meantime, we would love to receive and publish your memories, photographs, funny stories and general feelings about Yoshi. Yoshi will get her very own page on our website, as well as exhibit space in the Aquarium dedicated to her story, and we will use those spaces to create a shrine of sorts, made up of your pictures and words.
Please share Yoshi with us – you can email newsletter@aquarium.co.za to submit photos and memories, or if you have any questions.
News from Ingrid Sinclair at Two Oceans Aquarium
