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Blue whale numbers bounce back to near historic numbers

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Researchers believe that California blue whales have recovered in numbers and the population has returned to sustainable levels.

Scientists say this is the only population of blue whales to have rebounded from the ravages of whaling.

The research team estimate that there are now 2,200 of these giant creatures on the eastern side of the Pacific Ocean.

But concerns remain about their vulnerability to being struck by ships.

At up to 33m in length and weighing in at up to 190 tonnes, blue whales are the largest animals on the planet.

The California variety is often seen feeding close to the coast of the state, but they are found all the way from the Gulf of Alaska down to Costa Rica.

Writing in the journal Marine Mammal Science, researchers from the University of Washington say the California blue whales are now at 97% of their historical levels.

Working out that this species is now back at its traditional numbers required some dogged scientific sleuthing.

Whaling nations concentrated their hunting efforts on the colder waters of the Antarctic and until the practice was banned in 1966 some 346,000 of the animals were killed by harpoon.

The numbers of blue whales caught in the Pacific was much lower, approximately 3,400 between 1905 and 1971.

Much of this hunting was carried out by Russian fleets.

However most of the data on the catches was kept secret under the Soviet regime. Scientists have only recently been able to get access to this information in the archives.

However the location and size of the catches didn’t give any clues to the types of blue whales that had been caught. There are two distinct populations, the California group and others that live near Japan and Russia.

To figure out which whales were which, the scientists turned to song.

“We were trying to separate the catches into east and west, but we didn’t know the boundary between the two,” said Dr Trevor Branch from the University of Washington.

“So we used the current locations of where they sing to figure out the dividing line. Their repetitive calls are different.”

By being able to accurately work out the numbers lost to whaling, the research team was able to calculate a historic population.

Now back at 97% of their past numbers, the team believes that a rise in population has slowed down as these whales have reached the capacity of what the ocean system can support.

One concern for the scientists at present are ship strikes.

Most of these happen off the coast of California, and so worried are the authorities that they are now paying merchant shipping to slow down.

“Our perspective is that we’d rather there were no ship strikes at all, and they are over the legal limit,” said Dr Branch.

“They have to do something to stop it, but 11 per year is so much lower than historic catches.”

This new data suggests that there could be an 11-fold increase in ships before there is a 50% chance that the population will drop below what is considered “depleted” by regulators.

“My impression is that they are fairly robust,” said Cole Monnahan, also from the University of Washington and the lead author on the paper.

“If you can whale them pretty extensively for 50-70 years and they are able to recover I think that says a lot about moving forward.

“In terms of things like climate change, it is hard to predict but I don’t think we would expect a precipitous drop off.”

While applauding the success of the conservation efforts in the California region, the scientists are well aware that not all whale populations have managed to rebound. In Antarctica, blue whales are at approximately 1% of their historic numbers.

“California blue whales are recovering because we took actions to stop catches and start monitoring,” said Cole Monnahan. “If we hadn’t, the population might have been pushed to near extinction – an unfortunate fate suffered by other blue whale populations.”

 

Source: www.bbc.co.uk/news

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Spooktacular Underwater Adventure: Oyster Diving’s First Halloween Scuba Party at Mercers Lake

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halloween

Last Thursday, Oyster Diving transformed Mercers Lake into a hauntingly unforgettable underwater realm for their inaugural Halloween Scuba Party. Approximately 20 intrepid divers plunged into the darkness, weaving through a mesmerising scene of spectral decorations, glow sticks, and eerie underwater pumpkins.

halloween halloween

After the thrilling night dive, participants gathered to feast on a ghoulish spread of pumpkin soup, chilli con carne, and decadent fudge brownies, perfect fuel for the frightful festivities.

halloween

With a resounding success, Oyster Diving is excited to announce plans for this event to become an annual tradition. Next year, look forward to a fully licensed bar and live music, promising an even spookier celebration under the moonlit waters.

halloween

Join us next Halloween for an experience that promises to be a haunting delight!

Find out more about Oyster Diving at oysterdiving.com.

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Marine Life & Conservation

Shark Trust launches Oceanic 31 Shark Art Auction

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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.

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

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