Cephalopods – Page 3 – Learn to Dive Today Blog

Newsletter: The whales are coming

Hi divers

Weekend diving

Saturday: boat dives – 09.00 Atlantis / 11.30 Batsata Maze

Sunday: pool training with students

Dive conditions

So much bad weather for so long – too little diving and not enough sun. That’s my complaint for the week.

This weekend, Saturday is really the only option for diving. There is very little swell and not much wind, but it picks up in the afternoon. False Bay, however, has been hammered for the last few days by big swell, strong winds and lots of rain. The wind direction has been good for water clarity, but the swell stirs up everything and all the murky rain water ends up close to shore.

I drove the coast this morning to take a look. The Clan Stuart was a little murky from the swell, and Long Beach was clean, but from Ark Rock and down to Shark Alley the water was really dirty. A huge mudslide just north of Miller’s Point has also contributed to this. South of Millers towards the point the water looks clean and blue, so we will head off to Atlantis and Batsata Maze. If you are keen to dive, text me. We will meet at the Simon’s Town Jetty at 9.00 and 11.30.

There is a lot going on right now:

Whale entanglement

Yesterday I saw what I thought was a whale entangled in an octopus trap but lost sight of it after a while as the sea was extremely rough. Fortunately it was found again today and thanks to the the SA Whale Disentanglement Network it was freed. It has some serious cuts from the rope but they heal relatively quickly. There are octopus traps as well as whelk traps in False Bay between Glencairn and Kalk Bay, and in 2012 a 4.3 metre female white shark was caught in the ropes attached to the whelk traps and drowned.

We have been concerned about whale entanglement in these fisheries since they were announced; it appears our concerns were well founded. If you would like to ask some pertinent questions about the whelk and octopus fisheries, and raise an objection, I suggest you contact Dr C. J. Augustyn, Chief Directorate, Fisheries Research and Development at DAFF, by email at JohannAU@daff.gov.za or by mail at 5th Floor, Foretrust Building, Cape Town, 8000.

Brain food

Orca and dolphin talk

Simon Elwen and Ryan Reisinger are giving a talk on the Marion Island Killer Whale Project (on facebook here) and the Namibian Dolphin Project and soon to be Sea Search Africa in False Bay in a single evening. The talk is on Monday 16 June (a public holiday), at Bertha’s in Simon’s Town, at (about) 7pm. There is a cover charge of R25. Please rsvp on facebook! All are welcome.

Shark conference

There is a major shark conference taking place in Durban, out of which a constant stream of incredibly interesting information comes all day long thanks to a number of scientists live-tweeting the talks as they happen. Follow the tweets here.

Shark talk

Victoria Vásquez, a shark scientist at the Ocean Research Foundation and the Pacific Shark Research Centre in the United States, is giving a talk on shark conservation at OMSAC in Pinelands next Thursday evening, 12 June, at 7pm. If you would like to attend, rsvp here. She has been attending the Sharks International Symposium in Durban this week, so it’s a great opportunity to hear about the very latest shark research.

Finally, if you want to know how our own Department of Environmental Affairs plans to manage our marine resources, check out the recently published white paper here.

See you all soon!

regards

Tony Lindeque
076 817 1099
www.learntodivetoday.co.za
www.learntodivetoday.co.za/blog/

Diving is addictive!

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Video (TED): Edith Widder on filming giant squid

Giant squid – until very recently – are always seen dead, washed up on shore or floating at the ocean’s surface. This TED talk describes the Discovery Channel expedition that took place off Japan in 2012, which succeeded in filming a giant squid, alive, in the wild. The scientists used special, unobtrusive techniques to attract the squid so that they could capture it on film. You’ll hear about that, and see it in action, here:

[ted id=1684]

Yay science! And wow squid!

Series: Trawlermen, Series 1

Trawlermen is the British version of Deadliest Catch and the related spinoff series (Tuna Wranglers and Lobster Wars among them). The series (five episodes in this season) charts the activities of several fishing trawlers working in the North Sea out of Peterhead in Scotland. Having watched a lot of Deadliest Catch, we were well equipped to marvel at the restrained, unsensational voice-over narrative. The structure of the show is far more episodic, and each episode’s subject or arc is revealed early on.

The trawlers fish mostly for prawn, dragging huge nets along the sea floor. The bycatch from prawn trawling is significant, but I confess that I didn’t find it as horrific as I’d imagined it would be. Many of the fish are gutted and boxed for market, so not a lot of it seemed to go to waste. I do suspect that the full extent of the bycatch wasn’t shown. Trawling is incredibly, unbelievably destructive – for a scientific view on that, this article is a good start.

The trawlers also catch Greenland halibut, cod, squid, and a few other kinds of fish. They however are limited by EU regulations to a fish catch (technically bycatch) amounting to no more than 65% of their total catch, because they are prawn trawlers. Excess fish must be thrown overboard, whether it’s dead or alive. One of the boats pulls up a number of huge boulders, as well as a torpedo while fishing in Norwegian waters, which the crew swiftly decide is not live (it was full of sea water). They position the torpedo on deck, pointing away from the superstructure of the boat, just in case it goes off!

The boats are high-sided with deep holds in which there is a conveyor belt for sorting the catch. The smaller fish are gutted using a machine, while the larger ones are done by hand. Everything is flash-frozen in boxes, ready for market. The work on deck is dangerous as there are many moving parts, massive nets, and ropes all over the place. The crew are mostly quite reserved (with one or two camera-loving exceptions!) and speak in broad Scottish accents which – the producers of the series deem – occasionally require subtitles.

This isn’t a glamorous or easy job, and the conditions in the North Sea are rough and very cold. I didn’t find this at all to be a rehash of things I’ve seen in other fishing shows; it was fascinating to see how a trawler works, having seen crab fishing, lobster fishing, and tuna fishing. If the voice of Armageddon style presentation of most Discovery Channel productions annoys you, try this very civilised BBC production.

The DVD box set is available here or here.

Article: The Stranger on giant Pacific octopus

I think I prefer this article on octopus (the language is a bit less fruity, for one thing), but giant Pacific octopus are cool enough that even the most offensive writing about them can be interesting. A specimen has been weighed at 71 kilograms, but they usually weigh about 15 kilograms and can have arm spans of over four metres.

One octopus off San Juan Island grabbed a diver’s legs and held him underwater while he struggled, long enough that the diver used up most of the air in his tank and nearly died—as if the octopus knew that divers have only a certain amount of breathing time. Another octopus in Washington waters pounced on a diver, flaring its tentacles in a hunting gesture. The diver fended it off and swam away, but the octopus followed, crawling toward him on the ocean floor, and pounced again. Luckily, this octopus was small—but bizarrely aggressive for its size.

If you’re skeptical about the source of the above information, it’s from a Canadian Field-Naturalist journal article. An interview with Dr Roland Anderson, one of the authors of the journal paper, sheds further light on the “cold intelligence” of cephalopods (when kept in aquaria, they are notorious escape-artists), and their depressing sex lives (have sex once at the age of 3-5 years, then go mad and die). Anderson says giant Pacific octopus are not as smart as dogs or cats, but they are smarter than the average pet bird.

The article concludes with a discussion on cooking octopus. Kind of hard to contemplate after pondering their intelligence and remarkable physiology…

Read the full article here.

Series: Underwater Universe

The four episodes of this History Channel series cover waves, tides and currents, predators, and pressure – all powerful features of the ocean that can be sensationalised (some more easily than others) and presented for shock value and as imminent threats to human life. Full advantage is taken of this fact.

This very American offering doesn’t boast the measured, mellifluous tones of Benedict Cumberbatch or Steve Toussaint as narrator, but the line-up of (mostly in-studio) guest narrators is quite impressive. Bruce Parker (The Power of the Sea), Susan Casey (The Devil’s Teeth and The Wave), David Gallo (scientist presenter of the TED Talk I mentioned here), Scott Cassell (student of the Humboldt squid), Richard Ellis (writer of a number of ocean history, art and science books), and Neil Hammerschlag (shark scientist) were familiar to me, as was big wave surfer Ken Bradshaw, from this article. The strange, uncomfortable way in which the studio narrators were filmed, with silent close ups interspersed with talking, was very annoying and must have been incredibly embarrassing to shoot. Or perhaps the cameraman took the footage when the narrators didn’t realise they were being filmed.

Unlike BBC documentaries, which tend to rely purely on incredible photography and fluent narrative to convey information, the History Channel favours a CGI-heavy approach that we encountered in Treasure Quest, Deep Sea Salvage, and also in the National Geographic Shark Men series. For the subject matter of this series – particularly the sections on waves, tides and currents – it was very appropriate and informative. The first episode, devoted to tsunamis, rogue waves and “monster waves”, made good use of CGI to illustrate the concepts as they were explained. The series was produced shortly before the Japanese tsunami of 2011 (there is a hastily tacked on “thoughts and prayers” disclaimer) and features interviews with a survivor of a tsunami in Samoa. I am fascinated by rogue waves – the whole episode could have been devoted to them but they don’t make for good television – we only have indirect evidence of their existence. Also, I could have done with more footage of giant ships battling storms, but that’s what youtube is for…

The least interesting and most irritating episode was the one devoted to the ocean’s top predators, which suggested that orcas are a serious threat to humans. As evidence, the cases of captive killer whales drowning and injuring their trainers at marine theme parks were cited. No mention was made of the psychosis that these whales suffer from as a result of confinement in a small, barren, completely unnatural environment. An incident in which orcas inexplicably rammed and sank a yacht in the Pacific Ocean is also described and re-enacted. Whether the orcas did what they did because they wanted to kill the people on board is highly debatable. There is also a half-hearted attempt to paint whales as potentially vicious killers, recounting incidents when sperm whales rammed whaling boats in the 19th century. More power to the sperm whales, I say.

The other dangerous predators were (predictably) white sharks, Humboldt squid, saltwater crocodiles and Australian box jellyfish. There was a small environmental message at the end of this episode, mentioning that squid will probably end up the top predators in our oceans if current trends – fishing out large predatory fish and global warming in particular – continue.

The third episode, on the immense pressures that objects in the deep ocean are subjected to, was very interesting to Tony and me as divers. A confusing interview with a diver whose brother got DCS on a wreck dive leaves (I suspect) much out. Were they even qualified divers? Why was he surprised that his brother felt unwell and confused as to the cause after he popped to the surface from 30 metres after a 30 minute dive?

The bulk of the third episode, however, recounts a 1981 experiment called Atlantis III in which three volunteers were taken in a saturation system to a simulated depth of 686 metres while breathing Trimix 10 (70% helium, 20% nitrogen and 10% oxygen). It took 31 days for them to decompress. The chief of the experiment, Peter Bennett, was the founder and former CEO of DAN. There’s a more information about the project here – worth a read (download the pdf slowly), and a briefer account here.

The series concludes with an episode on tides and currents, including rip currents. The massive tidal range of Morecambe Bay in the United Kingdom, is discussed at length. At low tide, up to 300 square kilometres of mudflats is exposed, and flooded again when the tide comes in. The guides who escort people out onto the mudflats when the tide is out seem like charming individuals – it is recommended not to wander around at low tide without local guidance. In 2004, the rising tide trapped and drowned 23 Chinese immigrants who were working the cockle beds – with such a large expanse of land to cover, the rising tide comes in at great speed. There is also a harrowing re-enactment of a father and his two sons getting washed out to sea in a rip current in Kauai that should make you think twice about swimming at beaches with warning signs on them.

You can get the DVDs here if you’re in South Africa. Foreigners, go here or here.

Bookshelf: The Log from the Sea of Cortez

The Log from the Sea of Cortez – John Steinbeck

John Steinbeck was the author responsible for some of the best known works of American 20th century fiction – you may have read The Grapes of Wrath (or The Wrath of Grapes, as my sister is occasionally wont to call it) at high school, for example. The Log from the Sea of Cortez is a non-fiction work, recounting a marine specimen collecting trip that Steinbeck and his friend Ed Ricketts made in the Gulf of California, in 1940. This extremely biodiverse piece of ocean has been the site of studies of Humboldt squid, Shark Men expeditions, and studies of whales.

Ricketts was a biologist, and inspired some of Steinbeck’s fictional characters. The two of them chartered a fishing boat, and sailed from Monterey Bay and spent six weeks making various stops in the Gulf, anchoring the fishing boat and using their unreliable tender to travel to shore and back. They concentrated chiefly on the intertidal zone, and collected samples of as many species as they could find.

To most modern readers, accounts of them trying to spear manta rays and eating dolphin will be upsetting, but in general the curious delight that Steinbeck and his companions took in their discoveries is infectious. More than this, however, I enjoyed the way Steinbeck evoked life on board the fishing boat, the warm evenings, the companionship of the crew, and the sun-baked, sleepy towns they encountered en route. Steinbeck was distressed by Japanese shrimp trawlers wreaking havoc on the ocean floor, and horrified by the tons of bycatch (specimens, to him!) that was thrown back into the ocean, dead and dying.

In between accounts of their life on board the ship, and their forays to shore searching for specimens, Steinbeck ruminates beautifully and gently on man’s connection to the ocean and to everything else, materialism, contemplation, politics, love, freedom, and any number of other lofty themes.

We have thought often of this mass of sea-memory, or sea-thought, which lives deep in the mind. If one asks for a description of the unconscious, even the answer-symbol will be in terms of a dark water into which the light descends only a short distance.

A group of scientists reproduced Steinbeck and Ricketts’s journey in 2004; while the website that recorded their voyage has disappeared from the internet, a description of their expedition has not.

This is a book to be read during a summer holiday, or when one wishes to invoke the feeling of summer, and with ample time to hand for slow-paced philosophical musing. It’s a travelogue that says much about the interconnectedness of things, and more.

You can get a copy of the book here if you’re in South Africa, otherwise here or here.

Newsletter: Good mileage

Hi divers

Weekend launches

The weekend does not look all that rosy. A rather large swell is forecast and a little rain for tomorrow and Saturday, and then a fair amount of south easter for Sunday, but it blows later in the day so this is the plan:

Saturday 9.30 and 12.00, to Outer Photographer’s Reef and Maidstone Rock.

Sunday 8.00 and 10.30, to Spaniard Rock and the Brunswick / Caravan reef

All launches will be from False Bay Yacht Club. As usual, text me if you want to dive. We have Advanced students for Saturday and need to start early on Sunday as the wind picks up after lunch. These launches are subject to a final call early on the day as the swell may or may not affect us. It is always a sign of bad weather to come when big boats seek shelter in False Bay; at present two large ships have come into the bay, presumably to hide from the wind and swell.

Recent dives

We have had a good run of late and last weekend we were out on the boat on Sunday, Monday and Tuesday. The weather was not nearly as bad as the forecast so we had some good diving, as well as encountering a large number of extremely frisky whales. It was also good to see some new and old faces on the boat. The viz was not spectacular, but there was not too much wind or swell. Today we had 4-5 metre visibility at Long Beach.

We had really good mileage out of the white shark encounter two weeks ago and were fortunate to have the story run on a few local blogs, from which the Sunday Times got hold of it, and that led to a short radio interview on Cape Talk on Monday morning. That kind of exposure doesn’t come around very often, so thank you False Bay, Christo, Craig, the Russians and of course the shark. If you haven’t heard what happened, click here.

Two red sponge nudibranchs at Spaniard Rock

There are two red sponge nudibranchs in the photo above. See if you can see them: a bigger one just above the snail, and a smaller one to the right of the image. They are perfectly camouflaged!

Dates to diarise

The next ScubaPro Day is on Saturday 26 October. On that day we will be spending some time in airports on our way back from the Red Sea, so unfortunately our boat won’t be participating. If you’re keen to do some cheap boat dives and maybe try out some ScubaPro gear, however, diarise the date. More information will be provided in the next few weeks.

The next Cape Town Dive Festival is on 2-3 May 2014. More information on that will be revealed in the coming months, I imagine.

regards

Tony Lindeque
076 817 1099
www.learntodivetoday.co.za
www.learntodivetoday.co.za/blog/

Diving is addictive!

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Series: Shark Men, Season 2

Season 2 of Shark Men is more of the same as Season 1 – shouting, HOO-HAAing, chest slapping, and manly bleating. It’s not all complete, unmitigated suffering for the patient viewer, however. There is less focus on the manly art of extreme angling than there is in Season 1, which was a welcome relief.

The first two episodes are filmed at the Farallon Islands, a location off California that swarms with white sharks, and with which Tony and I are familiar from reading The Devil’s Teeth (recommended, with reservations). The team has a permit to capture and tag white sharks there, the first time anyone has been allowed to do this kind of work at the Farallons. Not everything goes according to plan, and the team’s research permit is suspended.

Attempting to tease out the entire life cycle of the southern Pacific white shark population, the Ocearch vessel drops anchor off Malibu in southern California. There they fish for juvenile white sharks, in view of the busy beaches. Surfers and swimmers are largely unaware that they are sharing the water with a white shark nursery. The researchers also return to Guadalupe Island off Mexico, and capture and tag more sharks there.

The final few episodes of this season are the most fascinating – a trip is made to the Sea of Cortez, a squid-rich ecosystem teeming with terrifying Humboldt squid, pods of sperm whales, and other cetaceans. There is a long history of white sharks of various sizes being caught in the area, which makes the researchers suspect that it is a pupping area. It is, however, a popular long lining location, which puts the white sharks in danger of being caught by fishermen.

This season of the show was dogged by controversy. The Farallon Islands permit revocation was of serious concern, and repercussions were felt long after filming completed. A shark known as Junior (or Lucky) was badly hooked and spent a long time out of the water on the Farallon Islands trip while the team attempted to remove the hook from deep in his throat. The shark was later filmed with a terrible injury to the side of his face. The Ocearch team were subsequently exonerated from any blame for the wounds, as Junior’s injuries were from another shark (and sharks bite each other frequently and indiscriminately).

There’s an interview with Chris Fischer and Brett McBride about this season of the show, here. Episode guide here. Get the series here, otherwise try here or here. You may have trouble getting them shipped to South Africa.

Series: Shark Men, Season 1

After the controversy, drama, self examination, and ultimately very interesting research that came out of the Ocearch expedition to South Africa early in 2012, we had to watch the television show that made Chris Fischer (amongst others) famous for working with white sharks.

Enter Shark Men, a National Geographic series featuring television personality Chris Fischer (who had something to do with getting the funding, or the boat, or both – try to disentangle it here if you’re so inclined) and Dr Michael Domeier, a respected white shark researcher. The researchers fish for white sharks off Guadalupe Island in Mexico, and then lift them out of the water in a specially modified cradle attached to the Ocearch boat. Water is pushed across the shark’s gills while they’re out of the ocean. The team measure and tag the sharks, and take samples for genetic testing. The sharks are released after 15-20 minutes out of the water.

The Ocearch boat also makes a trip to the Shared Offshore Foraging Area, or SOFA, where white sharks are believed to feed. A (giant) squid-rich ecosystem inhabited by sperm whales is found, and Domeier theorises that the sharks subsist on squid while they’re here. I found the two episodes covering the SOFA trip to be fascinating. There’s nothing special demarcating this piece of ocean – just the patterns made by the migrating white sharks, which show evidence that the sharks move between Guadalupe and the SOFA. Domeier believes that their time at Guadalupe is for breeding, and aims to take sperm samples from mature males to verify this theory.

The science is very interesting. During the course of the filming a couple of improvements in the handling of the sharks is made, of which I approved. There is magnificent footage of huge white sharks in crystal clear water. Unfortunately there is also a lot of testosterone-fuelled shouting, posturing, and remarkably inane commentary from a variety of sources. By the end of the series we wanted to watch with the sound off, it was that bad. The only person who comes off well at the end of it all is the captain of the Ocearch vessel and chief angler, Brett McBride, and it seems to be largely because he shuns the limelight and doesn’t say much.

I hate sport fishing. I think it’s pathetic that humans need to prove their mastery of the natural world by shooting or fishing the earth’s most amazingly put together predators. This show is mostly about fishing, and so I found it mostly repugnant. I understand that good television wouldn’t be the expected result from a quiet, respectful treatment of the shark while it’s being brought to the cradle – which leads me to question whether I think that something like this should be televised at all.

If you want the DVDs, get them here. They’ll only ship to the US, so make a plan (mine involved a friend, and a plane). Episode list here.

Dive sites: Brunswick

Tony and students on the surface over the wreck of the Brunswick

The Brunswick is a historical wooden shipwreck that lies a few hundred metres off the northern end of Long Beach in Simon’s Town, directly opposite the northern end of the white apartment buildings overlooking the Main Road. Like HNMS Bato, she is infrequently dived. Having lain underwater since 1805, she is heavily overgrown and much of her decking and hull is covered by sand. She used to be a shore entry (with a precipitous climb over the railway line), but in recent years a large number of boulders have been added as a breakwater between the ocean and the railway line, and climbing over in dive gear is no longer possible. For this reason we do the dive from the boat. Close to shore and in shallow water, the Brunswick is an ideal site to get used to boat diving.

The Brunswick was a British East Indiaman, which means she carried men and goods between Britain and the East Indies – (south)east Asia and India. She was carrying a cargo of cotton and sandalwood from China back to Britain when she was captured by some French vessels off Sri Lanka, and brought to Simon’s Bay. In September 1805 her anchor rope parted, and she ran aground during a south easterly gale. Most of her cargo was salvaged, as she lies in shallow (less than six metres deep) water.

Tags on the wreck from a prior archaeological survey

Some of the metal is worn smooth or recently uncovered

Side view showing how thick the planks are

Christo approaches the boat after the dive

We found the dive site to be similar to HNMS Bato, which was also a sturdily built wooden ship of similar vintage. The Brunswick was 1,200 tons, and her wreckage is spread out quite extensively. There are many thick, wooden planks, laid out as they would have been to form her decks, as well as much evidence of the bronze bolts that secured parts of the ship together. There are also many copper bolts, rivets and what could be small amounts of rolled up copper sheathing in evidence on the site.

Anemone among feather stars and papery burnupena

The highests parts of the wreck are covered with feather stars, anemones, sea cucumbers, and kelp. There are many octopus, and peering under the wreckage with a torch yielded a couple of very large pyjama catsharks. We were lucky to dive the site most recently on a day with lovely visibility, and the shallowness of the water means that there’s a lot of light penetration which improves things enormously.

The highest parts of the Brunswick wreck

Before diving this site, you should call the SA Navy Ops Room on 021 787 3818, to ask for permission and to tell them how long you’ll be. Same procedure as at Long Beach.

Dive date: 13 July 2013

Air temperature: 19 degrees

Water temperature: 15 degrees

Maximum depth: 5.4 metres

Visibility: 10 metres

Dive duration: 42 minutes

Mark helps Christo at the boat after the dive