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Construction Crews – who digs those holes in the sand?

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Gliders, Mantis Shrimps and Gorgeous Prawns… Mouth filled with sand, the Pennant Glider emerged from his hole and expelled the sand onto the growing pile at the edge of the hole. His partner darted into the hole and emerged with another mouthful of sand that he too spat onto the pile. Their burrow was formed in a crevice in the sandy rubble bottom and they had simply taken up residence in it and kept it clear. But the varying currents kept filling it, shells rolled into it, and they maintained it by suction and jet expulsion. This simple method of clearing a hole is used by many fish species as a sort of undersea vacuum cleaning system.

Not all such undersea residences are natural however. Some of the most impressive burrows on the reef are made by the Mantis Shrimp. They have immensely powerful front claws, and some species are able to break a camera lens with a blow. They can easily dig out a substantial hole in the sand on the reef, and Mantis shrimp are largely responsible for the more impressive holes on the reef.

The Giant Mantis creates a fully lined, superbly constructed burrow for himself in soft sand. These holes seem to be lined with a cement made with spittle and bits of sea-grass, and they are extremely strongly built.

Smaller holes become the home of Commensual Partnerships between a prawn and a goby.

The Goby can see and hunt but can’t dig, and the prawn can dig but is blind and can’t hunt. So they team up, and form a mutually beneficial relationship.

The goby’s task is to find food, and the prawn shares his bounty. The goby acts as the attack alarm, and is incredibly sensitive to movement and light. Few people know to wait and watch their interaction but it can be hilarious.

The prawn’s job is to dig and shovel the debris out of their home as it accumulates, depositing it in the right place by following the spine of the Goby with a feeler. The goby moves to point in the direction where the prawn must shovel the next pile of sand. This works very well until an extra goby arrives, or another shrimp joins the team.

We watched for half an hour as a pair of industrious shrimp both shovelled sand, small coral pieces and bits of shell out of the hole under the direction of a rather harassed-looking goby. The problem came when they both shoved at the same long coral piece, and it got stuck in the mouth of the hole. Looking baffled, his line of retreat closed, the goby darted off and hid under a rock. The two prawns shoved vigorously until the mouth of the hole ruptured, and a full day’s work dropped back into the hole. The goby came home, and you almost hear him muttering with rage as he haughtily dived through the debris to seek sanctuary below.

Where there are two gobies and only one shrimp sharing a hole, it is even funnier, as the two gobies point the prawn in opposite directions. We watched a completely paranoid prawn shoving a pile of sand and shells out of the hole as directed by the first goby and then pushing the same pile of sand back into the hole by following the spine of the second goby. The hole never changed, and we left before the prawn gave up.

Look out for holes in quiet corners on rubble or sandy bottoms, duck behind a rock, and watch. It’s worth it.


Words: Jill Holloway

Pics: David Holloway

Copyright: Ocean Spirit

www.osdiving.com

Jill Holloway lives in Mauritius and at Sodwana Bay Isimangaliso Wetland Park in South Africa. A PADI qualified Nitrox diver with over 1,500 dives, she is a passionate observer and preserver of the marine environment, and has a database of over 35,000 fish pics and hundreds of Gopro videos on fish behaviour, which she shares with her readers.

Competitions

WIN a Beuchat Air Light Bag!!!

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beuchat-logo-1-300x58.jpgFor this week’s competition, we’ve teamed up with our good friends at Beuchat to give away an Air Light Bag!

The Air Light Bag from Beuchat is a practical travel bag that takes up minimum storage space.

  • Material: 600 denier and 1,000 denier nylon/PVC
  • Soft roller bag, easily stored in its mesh bag
  • Internal retaining straps
  • Zip fastener with eyelets for padlocks
  • Side compartment for fins
  • Outer document pocket with coated zip and carry strap
  • Backpack style straps concealed behind the foam back-plate
  • Drainage vents
  • Red over-moulded wheels; detachable wheel block

To be in with a chance of winning this awesome prize, all you have to do is answer the following question:

In a recent post on Scubaverse.com (which you can read here), we reported that Mexico is to host the first annual Cancun International Boat Show and Marine Expo this year. But when is the event due to take place?

Is it:

  • A) 9th – 11th July
  • B) 16th – 18th July
  • C) 23rd – 25th July

Answer, A, B or C to the question above:

Beuchat Air Light Bag February 2021

Competition
  • Enter the country you live in
  • Terms and Conditions: This competition is open to all visitors to www.scubaverse.com except for members of the Scubaverse team and their families, or employees of Beuchat and their families or employees of Suunto Diving UK and their families. A valid answer to the competition’s question must be entered. If no valid answer to the competition’s question is entered, your entry will be invalid. Only one competition entry per entrant permitted (multiple entries will lead to disqualification). Only one prize per winner. All prizes are non-transferable, and no cash alternative will be offered. In the event that the prize cannot be supplied, no liability will be attached to www.scubaverse.com. When prizes are supplied by third parties, www.scubaverse.com is acting as their agents and as such we exclude all liability for loss or damage you may suffer as a result of this competition. This competition closes on 07/04/21. The winner will be notified by email. The Editor-in-Chief’s decision is final.

  • The following fields are optional, however if you fill them in it will help us to determine what prizes to source in the future.

  • Date Format: MM slash DD slash YYYY
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Miscellaneous Blogs

Jeff chats to… Jill Heinerth – underwater explorer, author and presenter (Watch Video)

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In this exclusive Zoom interview, Jeff Goodman, Scubaverse Editor-at-Large, chats to Jill Heinerth.

Jill is one of the world’s premier underwater explorers, and the first person to dive inside iceberg caves. According to filmmaker James Cameron, “More people have walked on the moon than have been to some of the places Jill Heinerth has gone right here on earth.”

An acclaimed polar explorer, cave diver, author, speaker, filmmaker, and climate advocate, Jill is the first Explorer-in-Residence of the Royal Canadian Geographical Society. She is the inaugural recipient of the Sir Christopher Ondaatje Medal for Exploration and Canada’s Polar Medal.

Jill leads expeditions into extreme environments to advance scientific and geographic knowledge. Her projects have been broadcast on the CBC, BBC, PBS, Discovery Channel, and television networks worldwide. Jill was announced as the recipient of the William Beebe Award from the Explorer’s Club and was inducted into the International Scuba Divers Hall of Fame in fall 2020.

Her bestselling book INTO THE PLANET – My Life as a Cave Diver  has drawn acclaim from the New York Times, Wall Street Journal, NPR, and O Magazine. Heinerth details her journey into the extreme world of underwater cave exploration, where she has had to overcome fear in order to go where no one has gone before.

Find out more about Jill and her work at: www.intotheplanet.com


Rather listen to a podcast? Listen to the audio HERE on the new Scubaverse podcast channel at Anchor FM.

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Competitions

Explore the amazing triangle of Red Sea Reefs - The Brothers, Daedalus and Elphinstone on board the brand new liveaboard Big Blue.  With an option to add on a week at Roots Red Sea before or after. 

Strong currents and deep blue water are the catalysts that bring the pelagic species flocking to these reefs. The reefs themselves provide exquisite homes for a multitude of marine life.  The wafting soft corals are adorned with thousands of colourful fish. The gorgonian fans and hard corals provide magnificent back drops, all being patrolled by the reef’s predatory species.

£1475 per person based on double occupancy.  Soft all inclusive board basis, buffet meals with snacks, tea and coffee always available.  Add a week on at Roots Red Sea Resort before or after the liveaboard for just £725pp.  Flights and transfers are included.  See our brochure linked above for the full itinerary.

This trip will be hosted by The Scuba Place.  Come Dive with Us!

Call 020 3515 9955 or email john@thescubaplace.co.uk

www.thescubaplace.co.uk

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