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SCUBA News 251
(ISSN 1476-8011)

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 news@scubatravel.co.uk. Or just let me know how long you've been a subscriber. Really looking forward to hearing from you.

What's New at SCUBA Travel?

Whale shark

Seychelles opens up to divers

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.

Hawksbill Turtle

Bajan Diving

Great for wreck diving, Barbados is also said to be home to the second-largest hawksbill turtle nesting population in the Caribbean.

Eco Blue...

Maldives marine conservation trips for families

Eco diving in the Maldives

Book now for $500 Off diving liveaboard. Full refund if COVID-19 travel restrictions apply.

Get Deal…

10 Fascinating facts about pufferfish - the most poisonous fish on the planet

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
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
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.

Puffed up pufferfish
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
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.

Masked pufferfish

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 puffer
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
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.

Dolphin with pufferfish
Giant puffer by Chiswick Chap, CC BY-SA 3.0


Diving News From Around the World

Our round up of the best underwater news stories of the past month. For breaking news see our Twitter page or RSS feed

black tip reef shark

Free pocket guides help shark identification and research
CITES has published two downloadable guides to help identify shark and ray species common in the Southeast Asian region.

Dolphin in boat wake

How can we conserve the Seychelles giant trevally?
To protect giant trevally throughout their lives, the nursery areas of this iconic predator need protection.


Pandemic made 2020 the year of the quiet ocean
Noise pollution from ship engines, trawling activities, oil platforms, subsea mining and other human sources declined significantly last spring - good for whales and other creatures.

Diver in Red Sea

Bow of sunken 18th century ship found in Egypt's Red Sea
Archeologists have uncovered the bow of the sunken ship on Saadana Island

Electric boat

The new wave of e-boats taking to the seas
Electric boats of all shapes and sizes are beginning to make a splash in the maritime sector.

Rubbish on the beach

Regulators missing pollution's effect on marine life
Chemicals and plastics, not just overfishing, threaten aquatic food chain with 'disaster', report warns

Mussel wired up

Mussel fitbit shows noxious water
When mussels feed, they open their shells; but if there's something noxious in the water, they immediately snap shut all at once. New fitbit for mussels gives early warning of toxins.

Seychelles fishing map

European tuna boats dump fishing debris in Seychelles waters 'with impunity'
Tuna love to congregate around objects adrift at sea, so industrial fishing vessels release thousands of man-made plastic-heavy fish aggregating devices (FADs) into the sea every year to round up the tuna.

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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