403-DEC

400+ issues

digi tal

AUSTRALASIA

www.divelog.net.au

December 2023 | No 403

Nigel Marsh & Helen Rose Gotham City

William (Bill) Gladstone Mourning Cuttlefish

Mike Scotland Phinisi Liveaboard Thailand

SPOTLIGHT Kevin Coombs

Mike Scotland’s Fish ID Course Moray Eels

PAPUA NEW GUINEA

Dive the majestic reefs of Kimbe Bay and the Bismarck Sea with us. Choose from a resort stay at WALINDI RESORT or a trip on one of the two liveaboards, MV FEBRINA and MV OCEANIA .... why not combine land based and liveaboard diving.

Contact our friendly reservations staff for a package to suit you. reservations@walindifebrina.com reservations@mvoceania.com

Image © Kyu Furumi

MV FeBrina has been operating from Walindi Resort since 1991. Image © David Doubilet Bismarck Sea, inc. New Britain & Kavieng

Walindi Plantation Resort celebrates 40 years of operation.

Our newest dive liveaboard operating out of Walindi Resort since 2019. Diving Bismarck Sea and Milne Bay

Diving Kimbe Bay Reefs

Image © Grant Thomas

Image © Grant Thomas

A boutique, traditional style live-aboard catering for 10-12 guests in 7 cabins, including large and small singles.

Tropical bungalows in rainforest gardens with waterfront and garden views.

MV Oceania is a 27 metre catamaran catering for up to

16 divers in 8 cabins. Modern comfort with two guest deck levels.

Image © Darek Sepiolo

Image © Franco Banfi

Image © Scott Johnson

WWW.WALINDIRESORT.COM

WWW.MVOCEANIA.COM | WWW.MVFEBRINA.COM

ADVANCED TECHNOLOGY. CLASSIC STYLE.

GALILEO 3 DIVE COMPUTER Sharp Color Display for Easy Readability

NEW

Merry Christmas to all of our readers from Vikki and I.

2023 has been a successful year for us. Dive Log magazine is going from strength to strength and our readership is growing steadily. We do a great deal of work in creating a world class scuba diving magazine. Vikki always creates a wonderful and professional presentation in graphic design so you can appreciate the high standard of photos and stories. We would like to increase our readership so that more divers can enjoy the quality articles from our highly expert team of contributors. We ask you to share with your diving friends so that they can enjoy a great read, discover new travel destinations and learn more about diving and the ocean. Go to www.divelog.net.au and subscribe to have it delivered to your inbox. As part of our focus on saving the ocean, we feature an insightful article on the mating of Mourning Cuttlefish by Bill Gladstone. Bill has captured excellent photos of the courtship and mating of our local species. His observations reveal more of the hidden secrets of these little treasures. My feature article is on Moray eels. As I always like to say, learning about marine life certainly does enrich your diving. This article showcases many species of Morays, Serpent Eels and Garden Eels and delves into their fascinating lifestyles. Read on, learn and enjoy. We feature two excellent u/w photographers, Kevin and Ann Coombs, from Cairns in our Spotlight and front cover. They were both prominent prize winners in the Cairns Nautilus photo comp for 2023. Kevin has also sent us a great article on wreck diving from Cairns. The consistently high quality of David Mullins’ articles on Nudibranchs continues. This time he explores creatures that take on the appearance of sea slugs. As usual, David’s knowledge and enthusiasm impresses. Ken Hoppen’s Simply Magic article takes us on a diving trip to Bohol. Ken’s articles are supported by great photos and filled with his passion and love of diving. OUR COVER PHOTO OUR KNOCKOUT FRONT COVER this issue was taken by Kevin Coombs of a Bowmouth guitarfish taken on the RMS Quetta a few years ago. The Quetta sunk after striking an uncharted rock in the Torres Strait on the 28 Feb 1890. Divers in the background are Max Gleeson (with video lights) and Ann Coombs. Camera gear: Nikon D7000, Tokina 10-17mm fisheye lens, Ikelite strobes.

Nigel Marsh has a press release on his new book Top 100 Hot-Spots For Sea Fishes In Australia . It sounds like a great Christmas present for the avid diver and U/W photographer.

Same goes for my book, Marine Biology in the Wild . This is a marine biology course in a series of easy to read, highly informative articles. It is a stand alone high class coffee table book and will appeal to divers who are curious to learn about the sea. I put many, many thousands of hours into this valuable resource for divers. I always say that I can guarantee that you will learn one hundred things from my book because it is filled with cutting edge information about marine life. Read it, absorb it and enjoy the benefits of its knowledge on every dive. The book is a perfect resource for U/W photographers seeking to improve their skills. It has so many postcard standard photos that you can try to emulate so you can become better. We suggest that you try to figure out how each photo was taken as a most powerful learning technique to develop and improve your skills. Contact me at mike@divelog.net.au or Vikki at divelog@divelog.net.au to order this excellent diving resource as the perfect Christmas present. It is a bargain at $40 plus p&h. Issue 403 of Dive Log Australasia has many other great articles including the inspiring diving experiences of Syed from Dive Heart Malaysia helping disabled divers to conquer their fear of diving, a great interview by Steve Jones on mindful healing and spirituality in diving. We always look forward to a huge dose of much needed common sense from Simon Pridmore on what makes a good diver. Simon has so many awesome insights to help us become better divers. There are many other great reads from our many loyal contributors, which have been on this journey with us to create Dive Log Australasia bi-monthly for scuba divers. We are looking forward to 2024 to many great safe diving adventures. We thank you all for your support and good wishes. Dive Log wishes you a Merry Christmas and a happy and prosperous New Year.

Mike and Vikki

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CONTENTS

digital

N o. 403 NEXT ISSUE DEADLINE : Issue 404 February 2024 Advert bookings 7th Jan Artwork due 17th Jan Editorial material : 7th Jan December 2023 EDITOR Mike Scotland | mike@divelog.net.au Production Editor/Designer Vikki Ryan | divelog@divelog.net.au PUBLISHER Mike Scotland | mike@divelog.net.au ADVERTISING Mike Scotland | mike@divelog.net.au MENTOR Barry Andrewartha | barry@motpub.com.au Tel: + 61 0415158168 mike@divelog.net.au www.divelog.net.au Editorial and photographic contribution guidelines: divelog@divelog.net.au The views expressed by contributors are not necessarily those of the publishers or its editors. REPRODUCTION OF CONTENTS No part of the contents of this publication may be reproduced without the prior written consent of the publisher. All images are copyrighted by the authors and photographers.

Features

022 Gotham City - Nigel Marsh & Helen Rose 026 Magic Oceans - Ken Hoppen SE Experience 030 Cairns Best Kept Secret - Kevin Coombs 034 Reclamation - Pink Tank - PT Hirschfield 038 DYWT Swim with Whales - Tonga- Pete McGee 042 The Phinisi Liveaboard- Thailand - Mike Scotland 048 SPOTLIGHT Photographer - Kevin Coombs 050 Limitless by Name - Oshim Somers - Steve Jones 056 Disabled Conquer Scuba Diving - Sabah - Diveheart 066 Mourning Glory (Cuttlefish) - William (Bill) Gladstone 072 MB Fish Identification - Moray Eels - Mike Scotland 082 Moray Eel Feed Report - Mike Scotland 084 EudiArt 2023 EudiShow Bologna - Risso/Mazzocchi

Regulars

07 - View from the Bridge - Mike Ball Exp. 10 - DAN News 12 - PNG Resort Listings 18 - Nudi Notes - David Mullins 53 - Counter Strike -David Strike 54 - Book Release Nigel Marsh 55 - Dive 2000 - Kevin Deacon 58 - Paul Watson Foundation News 60 - Diving Medicine - Simon Mitchell 62 - Historical Diving Society - Des Williams

64 - In Deep - Simon Pridmore 70 - Book Review - Mike Scotland 86 - Environmental News 88 - Boat Directory 90 - Southern Waters - Steve Reynolds 91 - SDFSA - Heather Creech 92 - Shipwrecks - Steve Reynolds 93 - Your Shot 94 - Parting Shot

DIVE LOG Australasia #403 - December ‘23 06

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Great Barrier Reef on the December

View from the Bridge Trevor Jackson - Spoilsport Skipper www.mikeball.com/blog

PHOTOS FROM SEPTEMBER/OCTOBER

by Trevor Jackson “Hello?’… “It is time.” Knock Knock

These are the first sounds of the morning. The night watchkeeper is telling me its 0600….Anchor’s about to come up. 5 steps and I’m on the bridge. A cup of black coffee fogs up the window just in front of the engine panels. Port engine start. Starboard engine start. On the front deck, two crew in beanies and long sleeves watch for the signal. A tiny nod and the anchor chain begins its 5 minute ‘clunk clunk’ on board. Once its locked away, our twin hulled magic carpet does a slow turn to face directly downwind. Moving now. Revs slowly increasing. Our next adventure is 20 minutes away. Through the door the sounds of breakfast being set up. Mostly it’s the clink of cutlery and the hum of a vacuum cleaner. The crew are busy now. On the closed circuit tv, the dive deck are checking that tanks are topped, water tubs are full. A gentle roll has them sloshing about. “What is the tie up skip?” Each time we come to a different mooring, we secure the boat to best suit the terrain and condi tions. Each one is unique. “Port side bridle”, I reply. Divers away now. I’m watching the descent from the wheelhouse windows. The water is sapphire blue, viz must be 40 of 50 metres, it gets like that out here…A lot. Little grey torpedoes are darting there and about. They know what’s coming. Some of them are not so little. All of them are ready for the excitement. The dinghy hovers above. A drum filled with tuna heads duck dives into the coming frenzy. The lid is popped, 30 seconds of mad action and its over…the torpedoes go about their business. Some got a feed, many didn’t. We don’t feed them so much that it affects the natural balance. The divers on the bottom fan out. There’s so much to see here at North Horn, all within reach if we don’t dawdle. And always there is that sapphire visibility that shakes our sense of reality. On deck an hour later, the place is humming like a nightclub. It’s all smiles and ‘WOWS’. Happy people in paradise. For me it’s a day at the office. Another knock at the door. Another cup of coffee fogs up the window. Port engine start. Starboard engine start…. our next adventure is 20 minutes away.

1st. Andrii Slonchak

2nd. John Edmondson

3rd. Jon Visser

Coral Sea & Great Barrier Reef! The Best Diving on the Dive with giant potato cod, explore deep walls, witness shark action at Osprey Reef.

New Special Expeditions! Check out our website for details.

Ribbon Reefs Suited to both Divers and Snorkelers.

www.mikeball.com #spoilsportlive #mikeballdive T:+61 7 4053 0500 E: resv@mikeball.com

Check out availability of Expeditions on Spoilsport www.mikeball.com/availability

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“ The reef systems here are some of the most pristine I have seen anywhere in my dive travels around the globe, and Wakatobi resort and liveaboard are second to none. The diversity of species here is brilliant if you love photography.” ~ Simon Bowen

Alternobaric Vertigo

T he sheer number of unique conditions that can trouble divers

Physiologically the symptoms are the result of the several factors. The pressure differential can lead to unequal stimulation of the fluid

filled semicircular canals of the vestibular system, which interprets head motion and orientation for balance. Differences in pressure on the right and left cochlea, which use sound stimuli to provide balance and source localisation, can also result in vertigo. Prevention The good news is that alternobaric vertigo is rarely serious and many cases resolve quickly and go unreported. It can also be prevented easily, and the chances of a serious injury are small if symptoms are recognised early. If, however, a diver fails to recognise the condition during onset, it can be easy for them to lose control of their position in the water, and a serious incident may result. The risk of alternobaric vertigo increases with any condition that causes inflammation or congestion of the ears and sinuses or difficulty equalising. This risk can be minimised by ensuring easy equalisation and adequate sinus function before a dive, combined with equalising early and often during the dive. Symptom onset is usually rapid, but in most cases the symptoms will disappear nearly as quickly as they came on — extended periods of serious vertigo are rare with alternobaric vertigo. Divers who experience symptoms during a dive should focus on staying still, maintaining their position in the water column and gently equalising. Symptoms should subside in a matter of seconds or minutes. Vertigo lasting more than a few minutes may indicate a more serious condition, such as a barotrauma of the inner ear or an eardrum perforation. DAN is here for you if you have any questions about your fitness to dive. And, as always, don’t hesitate to call if you experience symptoms after diving.

underwater is enough to make your head spin. From decompression sickness to gas embolisms to marine envenomations, there are plenty of problems to prepare for, and it takes effort to keep up with the latest research and treatment protocols. Conditions both rare and commonplace can put divers at risk, and it’s important to know how to identify those most likely to cause injury if they do occur. Alternobaric vertigo is one of the less-common conditions that can put a diver in danger quickly. Here’s what you should know about this pressure-related condition that can cause you to become disoriented at depth. surroundings spinning around you (vertigo), caused by a difference in pressure between the two middle ears. The condition most often arises during ascent or descent as ambient pressure changes, and the pressure in one or both middle ears is not equalised. This means that the condition can be caused by failure to equalise during the dive, although it’s worth noting alternobaric vertigo most often appears during ascent rather than descent. Audiovisual symptoms, including the perception that the body or its surroundings are spinning, involuntary rhythmic movements of the eyes, and nausea and vomiting can occur. A feeling of fullness, ringing, or muffled hearing in one or both ears may occur before symptom onset. Hissing or squeaking (indications of inadequate equalisation) often occur as well, and incident data indicates that women may be slightly more susceptible than men. Cause and Effect Alternobaric vertigo is the feeling of your

For more information about alternobaric vertigo, visit World.DAN.org/Health-Medicine .

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DiveA + World + 24/7 +

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over atment C ency Medical Medical Servic

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WORLD EVERYDIV

g D.DAN.or E VER SHOULD B ADANMEMBE

R

PACIFIC OCEAN

• Diving is possible all year round with the optimal season typically from mid April to mid June, and mid September to mid December.

KAVIENG

NEW IRELAND

MANUS ISLAND

VANIMO

BISMARCK SEA

• Water temperature from 26º along the edge of the Coral Sea and up to 31ºC in the Bismarck Sea. • Visibility ranges from 50 to 150 ft • PNG has a hyperbaric chamber maintained to international standards • The use of permanent environmental moorings ensures minimal anchor damage to reefs. • Weekly flights to Port Moresby from Singapore, Hong Kong, Tokyo, Manila, Kuala Lumpur, Honiara, Nadi. Daily flights from Cairns, Brisbane, Sydney. • For the best dive and air package pre-book your complete tour with a recognised PNG dive travel specialist.

RABAUL

WEWAK

KIMBE BAY NEW BRITAIN

MADANG

TARI

HOSKINS

MT HAGEN

GOROKA

PAPUA NEW GUINEA

BOUGAINVILLE ISLAND

LAE

SOLOMON SEA

GULF OF PAPUA

TUFI

PORT MORESBY

MILNE BAY

ALOTAU

www.walindiresort.com

www.lissenung.com “Instruction, gear rental, 8 rooms (6 with ensuite, 2 with semi ensuite), free WiFi, full resort facilities. A visit at Lissenung Island Resort is truly exclusive! info@lissenung.com

Instruction, gear rental, Nitrox, 12 bungalows, 8 plantation house rooms, all ensuites, internet, pool, full resort facilities, English. Voted the 'Best diving from a resort anywhere in the world', Walindi comprises fern-draped bungalows set in tropical rainforest gardens on the shores of Kimbe Bay.

resort@walindifebrina.com

MV OCEANIA LIVEABOARD www.mvoceania.com

www.mvfebrina.com

Gear Rental, Nitrox, 10-12 passengers, English MV FeBrina cruises from Walindi Resort, diving Kimbe Bay, Witu Islands, Fathers Reefs, Rabaul and New Hanover. febrina@walindifebrina.com

Gear Rental, Nitrox, 16 passengers, English

MV Oceania is the most recent liveaboard addition to Kimbe Bay. A 27 metre catamaran, Oceania began operation in 2019 with itineraries including Kimbe Bay, Witu Islands and Fathers Reefs as well as further afield at select times of year. reservations@mvoceania.com

Image credit David Doubilet

LOLOATA ISLAND RESORT www.loloataislandresort.com

NIUGINI DIVE ADVENTURES www.niuginidiveadventures.com

The only dive company established within ‘beautiful Madang’; the PADI certified facility, NDA is one of the most experienced dive operators in Papua New Guinea. NDA offers resort courses taught by our team of multi-lingual, PADI certified instructors and dive masters. The crystal clear waters surrounding Madang offer some of the world’s best diving experiences for divers to discover. Most

Luxury Island Resort with 68 rooms/villas, two restaurants and bar, a swimming pool, recreational beach, fully equipped dive shop, spa and conference centre. Importantly, it sits on the edge of the Papuan Barrier Reef and 29 dive sites around the island where experienced divers can explore its reefs, spectacular sea life and shipwrecks. There are also excellent snorkelling sites. Loloata’s PADI-certified dive and activities centre is opened now, so learning to dive is also now an option. t: +675 7108 8000 / 7914 3966 e : reservations@loloata.com

dive sites are only 5-10mins away! Underwater peaks climbing from 600m to 4m and sheltered lagoons where old wrecks, dating back to World War II, are waiting to be explored...Contact info: nda@madangresort.com

KARAWARI LODGE www.pngtours.com

TUFI RESORT www.tufiresort.com

AMBUA LODGE www.pngtours.com Fly across mainland Papua New Guinea to remote and magical Karawari Lodge. The lodge overlooks the Karawari River whose waters flow towards the Sepik River. Stilted villages line the edges of the waterways. Dugout canoes glide by. Lodge guides introduce guests to the complex and mysterious tribal culture. Conversations with villagers are fascinating. Photo opportunities abound. Explore mainland Papua New Guinea based from eco-friendly Ambua Lodge. The lodge is nestled in the highlands, overlooking the magnificent Tari Valley, home of the famous Huli Wigmen. Visit their traditional lands and learn about their fascinating culture. Follow walking trails through mid-montane forest, over traditional vine bridges and along clear mountain streams to secluded waterfalls. Watch for Birds of Paradise.

Discover Tufi in a boutique resort with 180 degree panoramic views over the sea and the only fjords in PNG. Experience diving in a secluded paradise with abundant sea life, coral reefs and wrecks. The warm crystal clear waters of Tufi are a divers paradise. Gear rental, water activities, village stays, cultural and land tours. 24 air conditioned ensuite guest rooms, pool, full resort facilities. reservations@tufiresort.com

service@pngtours.com

RONDON RIDGE www.pngtours.com

In the mountains of mainland Papua New Guinea, above the town of Mount Hagen, sits Rondon Ridge. Rising mists enhance the lodge’s panoramic views of the historic valley below. Orchids thrive here. Hours of walking trails offer opportunities to spot exotic birds, including Birds of Paradise. Lodge

guides share the history and traditions of the Melpa people. Rondon Ridge is conveniently accessible on scheduled flights between Port Moresby and Mount Hagen. service@pngtours.com

service@pngtours.com

TAWALI RESORT www.tawali.com

Instruction, gear rental, Nitrox, 22 ensuite rooms, Broadband, full resort facilities.Where it all started, discover the dive sites that place PNG into the world class map of scuba diving. Situated on a limestone bluff backed by densely rain

forested hills overlooking the clear and protected water of Milne Bay, Tawali offers travellers a unique location to dive, relax and enjoy the unspoiled wonders of this magnificent part of the world. reservations@tawali.com

SketchLight Action Camera Tray

Made in Melbourne

ACTION cameras are extremely popular with scuba divers, from the entry level Open Water diver through to the

most Technical of divers. The action

camera can be simply hand held, or attached to dive masks, scooters, helmets or anything you can imagine. Unlike still photography, where often large camera enclosures are attached to large camera trays that support extension arms holding strobe lights at a distance, most action camera

when someone sits their tank on your equipment.

SketchLight has prototyped and tested several different materials to

design a compact, super strong camera tray. Polyoxymethylene, also known as acetal or by its brand name Delrin®, was selected for its strong and seemingly unbreakable characteristics. The design of the camera tray is unique in the market place, sized to comfortably fit an action camera or small digital camera, with handles spaced adequately apart to provide additional image stabilisation. The camera is positioned forward of the hand grips to ensure your hands are never in the shot and ball mounts are provided at the top of the handles to attach the video lights. There is ample room to reach the camera controls and the camera mount allows the camera to tilt up and down. The camera tray has been designed by divers,

divers especially those shooting video, are usually not lucky enough to have a compact camera tray let alone have a couple of wide angle video lights. SketchLight has designed a camera tray specifically for a small action camera. Most

economical camera trays on the market are poorly designed, with multiple fasteners and other

components that you end up losing. They can be heavy and not overly robust and break easily, like

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for divers and was tested here in Australia before bringing it to market. SketchLight has a passion for Australian Made products with the camera tray being manufactured in Melbourne and the stainless-steel fasteners sourced locally. SketchLight has teamed up with OrcaTorch to offer the lowest priced package deal possible for the entry level video enthusiast. Offering the SketchLight action camera tray with two OrcaTorch D530V video lights and butterfly clamps, all you need is to add your action camera and you are set to record some excellent footage. For a limited time, SketchLight is offering all DIVELOG readers 10% off the entire range of products (including items on sale) by using the coupon code “ divelog ”.

www.sketchlight.com.au

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DIVE LOG Australasia #403 - December ‘23

The August and October NudiNotes discussed sea slugs that look like other sea slugs, for a number of complex reasons, and all the confusion that it causes taxonomists, the publishers of identification guides and us lowly sea slug aficionados. Sneaky, sly sea slugs indeed. Now we turn our attention to other forms of marine life that take on the appearance of sea slugs, mimicking them to various degrees of similarity. Those of you who are dedicated Nudi hunters will have, no doubt, been temporarily deceived by them at some point. The term mimic is used here in the loose sense of similar appearance rather than the strictest scientific meaning. FAKE - FRAUDULENT - FALLACIOUS

We often speak of defensive mimicry in nature as if it is something that the animal is trying to achieve in order to protect itself. This is incorrect. Mimicry is actually an undirected, random, evolutionary process brought about

by a combination of genetic changes (germline mutations) occurring during DNA replication, creating a different appearance, which are then passed onto successive generations, together with selection pressure

Mimicry by a juvenile ovulid (allied cowrie), Ovula ovum , of the toxic phyllidiid nudibranch, Phyllidia madangensis . This is a very close likeness given the different body forms of model and mimic. Left: The juvenile Ovula ovum . Centre: The phyllidiid nudibranch Phyllidia madangensis . Right: A pair of adult Ovula ovum illustrating the change wrought with maturity from a colourful mimic to an almost plain black mantle with minute papillae carrying a white tip.

Left: The polyclad flatworm Pseudoceros imitatus exhibits an uncanny resemblance, by colour, pattern, texture and size, to the extremely toxic and common nudibranch, Phyllidiella pustulosa on the Right. To the casual observer the only clues are a flatter appearance and the more easily discernible movement of the flatworm compared to the nudibranch. There are no dorsal gills to simulate and the marginal pseudotentacles formed by upfoldings of the anterior margin do an excellent job of appearing like phyllidiid rhinophores. The dorsal surface of its body also has a lumpy texture like the sea slug it seeks to mimic. This is not to suggest that this flatworm does not have its own store of toxic chemicals within its body. Although not yet proved, this may in fact be the case because if the visual deterrence fails then by having distasteful or toxic flesh usually the worst damage is limited to a bite mark. Additionally not all potential predators have the faculty of sight. It is certainly a better outcome to be only just bitten rather than completely devoured.

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Left: This Pseudoceros sp. is another flatworm with an appearance mimicking a phyllidiid nudibranch this time with an orange margin and also some tinting to some of the dorsal “pustules”. Right: Phyllidia exquisitia is one example of a probable model for this mimic.

within the habitat whereby those with a favourable mutation have a higher rate of survival. Selection pressure in the habitat related to mimicry is mostly derived from predator choice of prey. That selection process is influenced by prey mimicry confusing or deceiving the predator thus making that mimicry an anti predator adaptation. The evolved mimicry serves to either protect the animal from predation because it appears to be a form that a predator does not recognise/prefer or it appears to be a form that the predator thinks is noxious/distasteful. It is ironic that it is actually the predator, through that avoidance therefore, that eventually causes the creation of a mimic population. Mimic, model and predator are the three corners of the triangle driving this process. Of

course mimicry can also be used by predators to deceive prey but this is not relevant in this discussion about sea slugs. If we are talking about the appearance or resemblance of a mimic it is not just limited to colour and pattern but also shape, size and behaviour. The phyllidiid nudibranchs have proven to be a most successful model for mimics given their highly noxious and distasteful bodies, exposed presentation in the habitat and that the family contains many very similar looking species. Some polyclads (flatworms), polychaetes (scale worms), holothurians (sea cucumbers) and juvenile ovulids (allied cowries) utilise the colours and patterning and sometimes texture of the phyllidiids to their protective advantage. This

Left: This is the juvenile stage of the sea cucumber Pearsonothuria graeffei . As it grows into the adult its features change and gradually looks less and less like the toxic nudibranch it is mimicking during its most vulnerable stage. Right: The noxious nudibranch Phyllidia varicosa with blue to grey ridges carrying yellow-tipped pustules. The sea cucumber is certainly thinner and the “pustules” are more pointy but as in many cases of mimicry, presentation of certain features to a predator can be just as effective as a perfect match.

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A couple more mimics. Left: The polychaete scale worm Lepidonotus melanogrammus presenting a reasonable imitation of a phyllidiid nudibranch with the grey and white pattern and yellow-tipped swellings. The colour of this species can be variable depending on habitat/region. Right: Another polyclad flatworm - Pseudoceros sp. This flatworm has a more generalised mimic colour and patterning. It would seem to be “covering its bases” by mimicking several models belonging to the black-striped group of noxious Chromodoris nudibranchs. Chromodoris magnifica would be the closest model but as mentioned previously the mimic does not have to be a perfect match to deceive or confuse a predator. Exhibiting a few strong features = strong signals, to the predator can often be sufficient.

encompasses species from four diverse animal groups mimicking the one group of nudibranchs. There are also several flatworms that have developed the black striped notum common to the Chromodoris nudibranchs. Often these are not a perfect match to any one nudibranch species but are of a generic presentation that could be considered similar to several of the Chromodoris species with noxious dermal glands, in the habitat - “playing” therefore, the percentage game. As mentioned in the previous article, and it is worth repeating, the mimicry need not necessarily be perfect. Often a vague resemblance to a highly noxious species can bestow significant protection. It may be that the mimic is evolving towards the perfect look (evolutionary lag). Also, only certain traits may be necessary to deceive a predator and we, as humans, may perceive the mimicry different to how a predator perceives it. Other factors that might work against obtaining perfect mimicry include: the limit to the degree of change possible in their genomic structure and also the cost to the mimic, e.g. degree of change verses efficiency. The above is merely a brief introduction with some known, oft quoted examples. As with most biological subjects mimicry is a complex phenomenon. In fact it is quite difficult to establish that two animals with a similar appearance are the consequence of a lengthy mutation/selection process. However this does not diminish the likelihood of the similar appearance conferring a degree of protection. - References relating to this article will be appended to a related article to be placed on NudibranchDomain.org in the near future.

Upper: There are a number of Goniobranchus nudibranchs that present with a white mantle and variously coloured mantle margins. Lower: By sending the same generalised signal to predators this flatworm tunes into all the similar nudibranch anti-predator signals.

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Updated book for divers free online

Get it at: https://adsf.org.au/r/education

The Australasian Diving Safety Foundation is a charitable organisation created to enhance diving safety and does so by funding research, safety promotions and education. Over the past 4 years we have spent over $450,000 on various projects including subsidies for dive operators for oxygen units and AEDs, scholarships for doctors to study dive medicine, educational materials, and research projects. Information available at: https://adsf.org.au

Introducing the Brand New ADEX Australia Dive Show In Conjunction with OZTek Advance Diving Conference March 15/16, 2025 will see the inaugural ADEX Australia recreational dive and travel show in combination with OZTek Advanced Diving Conference. To be held at the Sydney International Convention and Exhibition Centre Darling Harbour Hall 2, on March 15/16, 2025 on the foreshore of Sydney City itself in the heart of the entertainment hub. ADEX Australia – an established and trusted show will open its doors to welcome divers, non-divers, students and families, with its specially curated programmes and festivities designed to entice more and more people to take an interest in our oceans. At the same time the show, in combo with OZTek will continue to serve as an invigorating platform for the diving community – giving them a voice and providing a space they can meet, foster relationships, exchange ideas and receive recognition for their achievements. ADEX celebrates 30 years in 2024 Learn more at: https://ozdiveshow.com.au/ADEX-Australia

An Australian Health Promotion Charity encouraging the prevention and control of diving related illness and injury through Research or Diving Safety Promotion Grants.

APPLY FOR A GRANT NOW www.adsf.org.au

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BRISBANE’S AMAZING GOTHAM CITY

:: text and images by NIGEL MARSH www.nigelmarshphotography.com

Helen Rose exploring the amazing Gotham City.

B risbane has dozens of fabulous subtropical dive sites located in the Moreton Bay Marine Park. Most of these dive sites are rocky reefs that are covered in corals, tropical fish and invertebrates, and are also a great place to encounter turtles, sharks and rays. Many of these sites are world class, but one stands out from the crowd as an epic dive – the amazing Gotham City. Located north-east of Moreton Island, Gotham City is a giant lump of rock that rises from 36m to 20m. Surrounded by a sandy desert, this isolated rock attracts marine life like a magnet, so is always an incredible dive. The site is famous for its fish life, including schools of pelagics, however it is also a great location to see squadrons of spotted eagle rays. Gotham City was only discovered about twenty years ago, and being a site for experienced divers only, it is not dived very often. The site is in open water and is often prone to very strong currents, so conditions have to be good to dive Gotham City. Brisbane Scuba are one of the few local dive operators that visit Gotham City several times a year on their 11m charter boat Voyager.

The strong currents that wash Gotham City make it a hard spot to dive at times. I have only dived the site five times, and had another five attempts abandoned by the strong currents. However, when the current isn’t too bad and you can get to the bottom, what awaits is mind blowing. That first view of the Gotham City monolith in clear water is stunning, a giant lump of rock rising straight from the sand and standing 16m high. I am not sure how big the rock is, as I have never had enough bottom time to reach the far end and tend to get side-tracked by all the marine life, but it is oval shaped and about 20m wide by maybe 80m long. Sheer walls can be explored on every side of this pinnacle, and these are riddled with many cracks and crevices. The centre of the rock is also cut by a gutter with several large overhangs to explore. The Invertebrates One of the most striking things about Gotham City is its corals. The top of the rock has a few hard corals and gorgonians, but coating the sides of this pinnacle are soft corals, gorgonians, sea whips, sponges and some very large black coral trees. The overhangs and ledges are a golden colour from a complete covering of tubastra corals. The sea whips here are very unusual as most a coiled like a giant spring. A close inspection of the black coral trees will also reveal a few tiger anemones, with this the only dive site in the area that I have seen these pretty rare anemones.

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Rarely seen tiger anemone at Gotham City.

The Fishes Fish are everywhere at Gotham City. Milling around all sides of the rock are schools of sweetlips, coral snappers, barracuda, rainbow runners, fusiliers, batfish, trevally and surgeonfish. I generally like to start a little deeper at Gotham City as it is the only spot in Brisbane

More common sea anemones decorate the top of the pinnacle and are home to Great Barrier Reef anemonefish. Other invertebrate species seen here include nudibranchs, sea stars, brittle stars, fire urchins, shrimps, hermit crabs, spiny lobsters, slipper lobsters, octopus and snake stars wrapped around the branches of the black coral trees.

Spiral sea whips are common at Gotham City.

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Crimson soldierfish under a tubastra covered ledge.

where you can see pearl perch. These fish are normally found in deep water, and being prized by fishers their numbers are low, so it is nice to see them mixed in with the schools of grey sweetlips. There are probably many interesting fishes on the sand at Gotham City, but being 36m deep doesn’t allow much time to explore this area. However, on a recent dive I was very surprised to see a pair of flagtail blanquillo, which are a type of tilefish that live in the sand. Stingrays and gropers are also commonly seen on the sand at the base of the pinnacle. Gotham City is also home to a great variety of reef

fishes. Commonly seen are butterflyfish, angelfish, wrasses, goatfish, hawkfish, soldierfish, squirrelfish, leatherjackets, morwongs, rock cods and scorpionfish. Some large goldspotted gropers shelter in the ledges, and this is also a good spot to find moray eels, trumpetfish and schools of bullseyes. The most colourful fish seen at Gotham City are the basslets, with dense schools of both orange and red-stripe basslet swarming around the rock and feeding on plankton. Spotted Eagle Rays are regularly seen at Gotham City, soaring around the top of the pinnacle. Large spotted and banded wobbegongs rest in the many ledges, and

Lyretail hawkfish are common at Gotham City.

The painted rainbow wrasse is rarely seen at other sites off Brisbane, but is common at Gotham City.

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Head out on the sand to see the uncommon flagtail blanquillo.

Gotham City is the only place I have seen pearl perch.

grey nurse sharks often visit the site in winter. However, divers have also seen sandbar sharks and schools of spinner sharks at this amazing dive site. I always enjoy diving the spectacular Gotham City, and one day I might even reach the far end! Brisbane Scuba dive all the wonderful dive sites off Brisbane each weekend. I also teach regular weekend NAUI Underwater Photography and Underwater Naturalist Courses for them.

For information and bookings visit Brisbane Scuba’s website at www.brisbane-scuba.com.au

Schools of orange basslets swarm at Gotham City..

Banded wobbegong at Gotham City.

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Simply

The diving at Magic Oceans is very diverse. There is a wide range of wall diving sites, backed up by some sandy slopes and some true muck dives thrown in. Most are less than a ten minute trip from the jetty by boat, the most about half an hour. We started with a shore dive from the jetty, where a short swim took us past two turtles to a shallow wall. Nice start! Magic! :: images and text by SE Experiences KEN HOPPEN L ocated on the south-eastern corner of the Philippine Island of Bohol, there is a resort that takes things to a new level. Magic Oceans takes some getting to, but it’s well and truly worth it!

After a ten-hour flight to Manila from Australia, an hour and a half flight back to Bohol, assorted stopover times, and a two-hour car drive from the airport, our little group expected nothing more than to be poured into our rooms at our 11pm arrival time. However, the staff at Magic Oceans were to prove for the first time, and not the last, that they are in a league of their own! We were promptly sat down to a three-course meal, which we were definitely not expecting, but on starting found we were really appreciative of! The entire kitchen staff, waitresses, administration and half the dive staff were all still up to greet us and make sure our stay started well. The resort is centred around its own swimming pool, with most of the rooms facing the pool, with those that don’t facing the ocean. A large bar leads towards the spacious eating area, and only ten metres on from there is the dive centre. After a sleep in and a morning gathering dive gear and setting up cameras, we ventured down to the water to start the week’s diving. We had managed to cop the tail end of a hurricane that was crossing into China, so the weather conditions for the first few days of our trip were a little on the windy side, dropping the viz a little and making boarding the boat from the jetty a little tricky. That didn’t stop us though!

A grey norse god Nudibranch was one of the more interesting nudibranchs we saw.

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Lamark’s angelfish is a common sight on the wall dives around Magic Oceans.

Close to the resort are Turtle Point and Magic Point, two wall dives that offer different vistas. Magic Point has a lot of sea whips, with zebra anemones prominent. Leopard shrimps are commonly sighted here, though no luck on that front for me this time. We did have a wide variety of xeno crabs and shrimp, with a plethora of colourful fish trying to obscure the reef wall. Turtle Point lived up to its name, with eleven turtles sighted on the wall dropoff. Seahorse Point brought gorgonian fans full of pygmy seahorses, often several to a fan. Mostly Bargibanti, with some Denise’s, all pygmy seahorses are a special find. The weather nearly defeated us for a couple of days, and we had to take a car for a half-hour drive eastward to Lamanok Point to pick up the banca boat and dive from

this new location. The diving from here was primarily muck diving, with fantastically coloured and large nudibranchs taking centre stage until we came to one dive site in particular. Larry’s Corner is a muck dive not to be missed. We did two dives here. The first one was notable for the number of wonderpus found. Six different individuals on the one dive makes this a wonderpus hot-spot in my opinion. One was easily the smallest I have ever seen, with a head less than 5m in length. It didn’t hand around long, and dove straight into the sand soon after it realized it was noticed. Two mimic octopus were also sighted on this dive, just not by me unfortunately. Swimming to catch up to my buddy I noticed a strange sight. A wonderpus was standing virtually straight up, looking a lot like some of the seagrass

Wonderpus are a great find at any time, six in one dive however will take some beating!

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A three spot angelfish pauses to look at me.

A larger female tomato clownfish poses with the smaller male.

structures in the area, and was happy to pose for a series of shots before lowering itself back onto the sand. I can only assume that it was surveying the area to see what was around, but I’ve never heard of this behaviour before or seen it in any octopus species. Not to be outdone, an unidentified sole, pretending to be a toxic nudibranch made a very welcome appearance. This was a fish I never thought I’d find, so to see one was something special. An hour’s surface interval saw us dive in exactly the same spot for a completely different experience. No octopus at all this time. Small thorny seahorses stole the show, as did a zebra crab on a small sea urchin. A small rocky bommie in the middle of the sand desert proved to have a wealth of critters on it, from a large blenny that wasn’t afraid to show its face, to both juvenile and mature dwarf lionfish, Djibouti shrimp, and quite a few goldspotted sweetlips. Sleeper gobies were out in force, as was a leatherjacket pretending it was a leaf, and a harlequin snake eel that was far less shy than most. One of our days here was spent on a trip around the southern parts of the island. Whilst here there are many things to see and the Chocolate Mountains are top of the list. We dropped in on a tarsier rehabilitation facility to see these small primates, and also to a long-tailed macaque sanctuary. For the more adventurous there was the opportunity to zip line across a canyon and back, as well as spending an hour on quad bikes zooming around a large reserve. There is plenty to do for non-divers here too! Whale sharks are on the agenda here too. They are often seen on the wall dives here, passing as the divers complete their daily dives. Down the coast at Tagbilaran there is a whale shark encounter that works the same as that in

Most of the turtles in the area that we sighted were green turtles, with an occasional hawksbill thrown in.

The colours and variety of nudibranchs in this area is

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Oslob, where the whale sharks are fed small amounts of shrimp to keep them interested in coming in the morning hours. Our trip here had dirty water, but still the whale sharks were visible to our group of snorkellers. Mention must be made here of all of the staff that made our visit here special. Dive guides Ailyn and Lee Ann, ably supported by Larry, Jay-R and all of the boat crew. Evelyn ably looks after the bookings, and Ester and Ian do a great job at the bar. The entire kitchen staff have to be applauded for their efforts as the standard of the meals here was nothing short of excellent, and we had a chef who could sing too! Three of our party had birthdays during the trip, and the kitchen managed a superb cake, and an even better rendition of ‘Happy Birthday’. These are the things that make a holiday stand out. The best way to describe the diving and the resort here is to make a simple statement. We’ve already decided to go back. ☼ Some of our group enjoying lunch on a river cruise in Bohol. Left : A beautifully patterned warty frogfish hides in a nook on a wall.

The zip line spans over half a kilometre over a river. About 180m over the river!

Lemonade and sunsets at Magic Oceans Resort in Bohol. Photo Credit Madhi Mahakumbura.

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CAIRNS’

A fter years of diving on the reefs off Cairns I started to feel a desire to do something different, so in January 1994 I set out to find the wreck of the “Trinity Bay” sunk in deep water in between Euston and Flynn Reefs in 1981. It was supposed to have gone down over the continental shelf but remained defiant and stayed afloat, originally intended as target practice for the Airforce, the Navy had been called to the rescue, as the old dredger then converted to a floating restaurant refused to give up the ghost. BEST KEPT SECRETS ::images and text by KEVIN COOMBS

By this stage, she had drifted back into shallower water but at 56 metres was not considered a shipping hazard. At about 30 nautical miles offshore, lying-in open water conditions are only favourable for diving the “Trinity Bay” in the calm summer months. It is far from being a dive for novices due to the depth and often swept by northerly currents though being so far offshore the visibility is often good, one can make out the shape of the wreck at about 30 m. The deck is almost void of growth but along the sides of the boat is decorated with many Gorgonians, Sponges and Sea Whips and has an assortment of Aquarium fish not found in the shallower reefs. Baitfish are the constant source of food for the pelagics, cod and coral trout which inhabit the wreck. Planned correctly and with a good supply of air, pony and stage tanks “Trinity Bay” can be an extremely rewarding diving experience.

After being inspired by my first experience I gained knowledge from local fishermen of another object, this time only about one nautical mile off Green Island known by local fishermen for many years as a shipping container fallen off a boat. I decided to do a dive and investigate for myself. My son Simon and I set out to find the shipping container armed with co-ordinates given to me, it was not difficult to locate using a GPS and sounder. . At just 40 metres to the bottom it was an adventurous dive but one that will be the greatest highlight of my diving career. I will never forget my first dive on this wreck in September 1995. The sight that confronted me as the dark shape that loomed out of sightly murky water and materialised in front of my eyes sent my heart beat racing and it wasn’t only the swim against the steady current down the wreck. We were greeted by a gigantic marbled ray that had had its tail

Green island wreck (fish)

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