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SCUBA News (ISSN 1476-8011)
Issue 250 - April 2021
Welcome to the 250th issue of SCUBA News - thank you so much for subscribing.
We sent our first newsletter 21 years ago! During that time we have featured 107 marine animals and and one marine plant. We've reviewed scuba books and interviewed diving authors. Plus we've covered the diving in nearly 100 countries and territories. I hope you've enjoyed reading the newsletters - either as a new or long term subscriber. Any ideas for articles, or a creature of the month, e-mail firstname.lastname@example.org. Or just let me know how long you've been a subscriber. Really looking forward to hearing from you.
The Seychelles are protecting 210,000 square kilometres of its ocean, limiting their use to research and regulated tourism while prohibiting harmful activities like dredging and oil prospecting. With just six COVID-19 deaths in total they have now ceased the need to quarantine when visiting.
Great for wreck diving, Barbados is also said to be home to the second-largest hawksbill turtle nesting population in the Caribbean.
Maldives marine conservation trips for families
Book now for $500 Off diving liveaboard. Full refund if COVID-19 travel restrictions apply.
1. They are the most poisonous fish in the sea
The Puffer is harmless, unless eaten. The liver, intestines, gonads and skin are highly poisonous and cause death in around 60% of people who eat it. If prepared properly the puffer (or fugu) is edible and considered a delicacy in Japan and Korea.
The Puffer's toxin - tetrodotoxin - is produced within the pufferfish by bacteria. The fish acquire the bacteria by grazing on the reef and eating molluscs and other invertebrates. Weight-for-weight, tetrodotoxin is up to 100 times as deadly as the venom of the black widow spider and over 1000 times more deadly than cyanide. It is one of the most poisonous natural substances.
Guinean Pufferfish, Sphoeroides marmoratus, taken in the Azores by Tim Nicholson
2. They are the only bony fish which can close their eyes
But they don't have eyelids. Instead they pull their eyeballs deep within their sockets to a depth of 70 per cent of the eye's full diameter - among the greatest eye-sinking depths ever recorded in an animal. They then squeeze the skin surrounding the eye closed.
Eye of the pufferfish by Gray's Reef National Marine Sanctuary - CC BY 2.0
3. They are masters of self-defence
Not content with being one of the most poisonous animals in the sea, when threatened they greatly inflate themselves with water, making themselves look much larger than they usually are. They do this by rapidly gulping water into their extending stomach. This makes them into a spiny ball three to four times their normal size. It's not good for the puffer fish though, so they only do this when seriously threatened.
Photographer: Jerry Mclelland, Credit: Charleston Bump Expedition. NOAA Office of Ocean Exploration
4. Pufferfish don't have scales
Instead they generally have spines. These normally lie flat but when they puff up the spines erect.
Masked pufferfish, Arothron diadematus, by Tim Nicholson. This pufferfish only lives in the Red Sea.
5. One makes huge, beautiful nest patterns in the sand
Although the fish are only small, they make geometric nests 2 m across, and it takes them a week or more to do so. They even decorate their creations with shells. Male fish do this to attract a mate. They never reuse the nest, always constructing a new circular structure in spite of the time and effort it takes. It was only in 2015 that the fish that constructed these masterpieces were described as a new species, Torquigener albomaculosus.
6. They have just four teeth which continually regenerate
Adult pufferfish have just four teeth, fused together into one strong beak. They use this to open clams or mussels, and scrape algae off rocks. These teeth can regenerate indefinitely, so they never become completely ground down. The four teeth gave rise to the name of their family: Tetraodontidae.
7. Baby pufferfish are cannibals
The larvae of the tiger pufferfish, once it has grown its first teeth, starts attacking its siblings which haven't yet done so. As these baby fish have very small mouths, rather than swallowing their brothers and sisters whole would instead bite lumps out of them, causing plenty of deaths.
Larva by Allan Connell
8. There are over 200 species of pufferfish, living in either fresh or salt water
Two hundred of types of pufferfish make up the Tetraodontidae family.
Sharpnose pufferfish, Canthigaster papua, Dr. Dwayne Meadows NOAA/NMFS/OPR
9. Some pufferfish are over 60 cm long
Pufferfish range in size from the tiny freshwater pygmy pufferfish at 3.5 cm to the giant pufferfish, also found in freshwater, at 67 cm long.
Giant puffer by Chiswick Chap, CC BY-SA 3.0
10. Dolphins use them to get high
Footage from a BBC documentary series, "Spy in the Pod," reveals what appears to be dolphins getting high from pufferfish. The dolphins were filmed playing with the puffer, passing it between each other for 20 to 30 minutes at a time. Afterwards they're shown swimming "dreamily". The pufferfish are generally alarmed but unharmed.
Free pocket guides help shark identification and research
How can we conserve the Seychelles giant trevally?
Pandemic made 2020 the year of the quiet ocean
Bow of sunken 18th century ship found in Egypt's Red Sea
The new wave of e-boats taking to the seas
Regulators missing pollution's effect on marine life
Mussel fitbit shows noxious water
European tuna boats dump fishing debris in Seychelles waters 'with impunity'
SCUBA News is licensed under a Creative Commons Attribution 4.0 Unported License. This means we are happy for you to reuse our material for both commercial and non-commercial use as long as you: credit the name of the author, link back to the SCUBA Travel website and say if you have made any changes. Some of the photos though, might be copyright the photographer. If in doubt please get in touch.
Photo credits: Tim Nicholson, Jill Studholme, Kristin Riser, Jianye Sui
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