Article: The Atlantic on how much of the sea is fished

The proportion of the world’s oceans that are fished has recently been the subject of two papers in Science, both of which used the same data set to reach different conclusions. One study concluded that 55% of the ocean is affected by fishing, while a follow up (using the original data set, but at finer resolution) concluded that the number is closer to 4%.

A janbruin emerges from a school of fish at Atlantis
A janbruin emerges from a school of fish at Atlantis

Ed Yong of The Atlantic sets out the disagreement, and explains the subtleties and the points of view on each side of the debate. Far from being an insoluble  scientific crisis, the divergent findings show the iterative nature of the scientific process and the manner in which back and forth between scientists leads to progress. It brings to light important questions worth considering, ones that are more important than simply asking the original question of how much of the ocean is fished.

Instead, you have to ask different and more refined questions. How much of that fishing is sustainable? Which species are being targeted? How are they faring? Can they bounce back?

Read the full article here.

Bookshelf: Shark

Shark – Brian Skerry

Brian Skerry is a National Geographic photojournalist, with whose TED Talk you may be familiar. This book is a collection of articles – about sharks – that appeared in National Geographic magazine, accompanied by one magnificent shark photograph after another. Each chapter’s text is reasonably short. Here, the photos are the primary focus.

Shark
Shark

The chapters focus on four species of shark: great white, white tip, tiger sharks, and mako sharks. Additional text is contributed by several National Geographic writers, and experiencing the familiar editorial quality and stylistic approach of the magazine is like settling down for a chat with an old friend.

The final chapter of the book, written by Skerry, is an appeal for increased understanding of sharks and their vital place in ecosystems, and increased protection for them – in the form of marine reserves, and less fishing, for example. The photographs selected for this chapter makes it clear that in Skerry’s view, science (especially tagging studies) is vital to the endeavour of better understanding sharks, and protecting them.

Get a copy of the book here (South Africa), here or here.

Bookshelf: Manta

Manta: Secret Life of Devil Rays – Guy Stevens & Thomas Peschak

I found this book to fill a significant gap in my manta ray knowledge, which was (to be honest) virtually nonexistent. Author Guy Stevens is founder of the Manta Trust and a Save Our Seas project leader, and has spent 15 years in the Maldives studying these enormous, charismatic elasmobranchs. The Manta Trust co-ordinates global manta research efforts, with the aim of protecting and conserving mantas and their relatives.

Manta
Manta

The photographs in this book are by Thomas Peschak, co-founder of the Manta Trust, with whose extraordinary work you should be familiar. (If not, look here, here and here.)

Everything you might want to know about mantas is here, without being glib about the fact that there is still much we do not understand about these animals. The text covers their biology, life histories, threats to their survival, an identification guide, and numerous accounts by field scientists who study mantas and devil rays. (It was hard not to be envious reading some of the day-in-the-life bits!)

This is a beautiful, substantial book. Get it here.

Bookshelf: Between the Tides

Between the Tides: In Search of Sea Turtles – George Hughes

I have been late in coming to this book, which was published about five years ago. George Hughes is a world-renowned, South African turtle scientist whose work has done much to ensure protection for sea turtles in the southern Indian Ocean. He was the guest speaker at an event held at the Two Oceans Aquarium to celebrate the release of Yoshi, the loggerhead turtle who spent over 20 years at the aquarium and is now powering along the Namibian coastline in rude health.

Between the Tides
Between the Tides

Dr Hughes was CEO of the Natal Parks Board and then Ezemvelo KZN Wildlife, but Between the Tides relates his early career as a student looking for turtles along South Africa’s wild north east coast, in places that today support thriving dive and fishing charters. His legacy of turtle research continues.

Turtle surveys were conducted around Madagascar, the Comores, Reunion, the Seychelles, and on the Mozambique coast. The fact that the iSimangaliso Wetland Park now exists, offering a protected and well-regulated breeding environment for three species of turtles (loggerhead, leatherback and green – discovered there in 2014) is thanks to the early and persistent work of Dr Hughes and his colleagues. Turtles were first found nesting on this piece of coast in 1963, when it was still completely wild and mostly neglected by the authorities. In this book Dr Hughes recounts the development of the tagging program that he started, in which over 350,000 hatchlings were flipper tagged and/or marked over a period of 31 years.

Only about two out of every 1,000 hatchlings survive to return to the area in which they hatched, to breed. Female loggerheads are estimated to reach maturity around the age of 36 years, during which time they navigate an ocean of threats. This makes every surviving hatchling incredibly valuable.

The recovery of the number of loggerheads, in particular, has been quite spectacular, with more modest but noticeable gains in the leatherback population. More recently, as technology has allowed it, satellite tagging has shown their movements around the Indian ocean

If you find a baby sea turtle on the beach (this is the time of year when they start washing up), here is what you should do. The most important thing is to keep it dry, and to contact the aquarium as soon as possible.

Dr Hughes also discusses the sustainable use of sea turtles (for example, for food), something which I’d never thought about and which for that reason is fascinating – and very challenging to come at with an open mind, and appreciating the viewpoints of a scientist who has been steeped in turtle research for most of his life.  This is an excellent, proudly South African marine science book, written to be accessible even to those who aren’t turtle fanatics a priori. Highly recommended.

Get a copy of the book here (South Africa), here or here.

More stingrays under the boat

We spent quite a bit of time with the short tailed stingrays (Dasyatis brevicaudata) between dives this past summer. Here’s another short video of one under the boat in shallow water.

These rays can grow to over two metres in diameter and weigh a few hundred kilograms at their maximum. They are a popular target for fishermen.

Bookshelf: Life’s a Beach

Life’s a Beach: Your Round-The-Coast Guide To South African Beaches – Ann Gadd

Compliments of the season. If you’re contemplating which beach to head to for tomorrow’s traditional Boxing Day beach outing, a venerable South African institution, I have just the book for you. The product of a mammoth investment of time (which couldn’t have been all bad) and distance travelled, Life’s a Beach is a handy guide to (possibly, probably, almost) every single beach along South Africa’s coastline.

Life's a Beach
Life’s a Beach

Each pair of facing pages covers a stretch of coast, and beaches are rated for surfing, alongside information about swimming, kiteboarding, wake boarding, kayaking and canoeing, diving, fishing and hiking. The scuba diving information for the sites around the Cape Peninsula, with which I am familiar, is reasonable, but of necessity very abbreviated owing to the book’s format and primary focus. It goes without saying that you should seek out some local knowledge before diving in an area you haven’t visited before.

Unique experiences and best kept secrets (no longer – haha!) are highlighted, as well as the presence of braai and picnic facilities. Tips on where to go for sundowners are also included. Child friendly activities are mentioned where applicable, too.

Access tips, as well as warnings about rips, pollution, sharks (thank you Shark Spotters!) and whether a beach has Blue Flag status round off the comprehensive information that is provided in a handily concise manner. This book will be extremely useful when you’re visiting an unfamiliar stretch of South Africa’s coastline, and particularly invaluable when it’s a little known and less popular beach.

Get a copy of the book here, or here if you’re outside South Africa.

And if you’re going to the beach in Cape Town tomorrow, make sure you’ve downloaded the free Shark Spotters smartphone app. Get it here for your iPhone, and here for Android.

Biscuit skate on a night dive

We came across this small biscuit skate (Raja straeleni) while doing a night dive at the jetty in Simon’s Town, on the occasion of Diversnight 2017. They are found in the eastern Atlantic ocean all the way down to 700 metres depth, grow really slowly, and are frequent bycatch from hake trawling operations off the South African coastline. SASSI says don’t buy it. The species is data deficient on the IUCN Red List.

These skates have thorn-like stings along part of their tails, and this one seems to have a whole lot else going on in the tail region which looks as though it would help him camouflage among seaweed. (None of the biscuit skates pictured in our fish identification books have quite such fancy tail-gear.) Also watch how he flicks sand over himself for additional disguise when he stops moving.

Also, they can jump – perhaps a little known talent… Once, while Clare was on duty at the aquarium, a small one leaped right out of the shallow ray pool that used to be next to the touch pool, and landed on the floor. It was a quiet Sunday afternoon. A quick manhandle and he was replaced in his pool (and that exhibit was moved soon after)!

Article: Buzzfeed on what to do with a giant squid

I can’t remember how this story crossed my path – I usually only visit Buzzfeed when someone sends me a link containing cat pictures – but it’s definitely worth your time. I thought I’d share it now, before we (hopefully eventually) move on from the cephalopod obsession that I have been nurturing for a while.

The article describes how the curator of molluscs (cool job) at London’s Natural History Museum came into possession of a giant squid, accidentally caught by fishermen in the Falkland Islands, and what it took to preserve it.

She measures 8.62 metres in length and remains the largest wet specimen the Natural History Museum of London has ever preserved. No one has ever captured and preserved a giant squid as complete as this one. That said, she’s missing part of a leg – but it’s not her fault. The fact that she was so fresh meant a section of one of her tentacles could be immediately frozen for DNA research before decay set in.

You, too, can see a giant squid, if you do a behind the scenes tour at London’s Natural History Museum. If you’d like to remind yourself what a giant squid looks like in real life, this talk is a good place to start. Read about giant squid here.

Read the full article here – the accompanying photos are probably even more gripping than the text

Newsletter: Colouring in

Hi divers

Weekend dive plans

No diving

Those dreaded purple crayons have been used on the weather forecast for the weekend, which mean 50+ kilometre per hour winds. Diving is sadly out of the question. Fortunately the direction is good for both improved visibility and some sorely needed rain. If the forecast holds we should have good rains and a week of northerly and/or westerly winds, which will translate into crystal clear water in False Bay once it drops off. Hold thumbs!

Table Mountain from Milnerton
Table Mountain from Milnerton

Dates for your diary

Don’t forget there’s a talk about South Africa’s inshore marine resources, scheduled for this coming Wednesday, 18 October, at 7.30 pm. More information can be found here.
The following (Thursday) evening, 19 October, there’s a talk about The Gantouw Project, which has reintroduced eland to conserve fynbos on the Cape Flats. Sound interesting? More details here.

regards

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

Diving is addictive!

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Bookshelf: Into a Raging Sea

Into a Raging Sea: Great South African Rescues – Tony Weaver & Andrew Ingram

I insensitively packed this book for Tony to read while we were aboard MSC Sinfonia for the BirdLife cruise we took in April. It’s a rip-roaring read about various rescues that the NSRI has been involved with over the years, but – perhaps unsurprisingly – Tony wasn’t keen to read about maritime disasters (even ones that ended well) while we were at sea.

Into a Raging Sea
Into a Raging Sea

The book was produced to commemorate the 50th anniversary of the NSRI. There is an element of history – describing the origins of the organisation, and some “sea rescues of yesteryear”. But the bulk of the book describes rescues that took place in the last 15 years. Some of them, such as the sinking of the whale watching boat Miroshga off Hout Bay’s Duiker Island, will be all too familiar from the ensuing press coverage. Others were less familiar, but no less interesting to read about.

One of the things I loved about this book was that it reveals the men and women behind the daring, often dangerous rescues. The rescuers are allowed to recount the events they experienced, using their own words, and this is revealing. These rescuers are not usually lionised by the general public or, as a rule, afforded prolonged media attention, and neither does this book glamorise them or romanticise their achievements. The challenge of the rescues – and occasional raw fear felt by the rescuers –  are vividly portrayed. The writing is beautifully matter of fact, without downplaying the seamanship, strength of character and perseverance required to do this (unpaid) work.

It reminded me fondly of the “drama in real life” stories that I used to devour from the pages of the Readers Digest magazines my grandmother used to bring whenever she came to visit. There are many, short chapters, each one offering its own little catharsis. The rescues span South Africa’s coastline, as well as a few other locations, and not all of them are maritime disasters.

Proceeds of this book support the NSRI. Get a copy for yourself, and all your friends. It will entertain anyone who loves a good story of heroism and adventure, and it will encourage anyone who’s feeling jaded about humanity’s capacity for good. It’s an excellent read.

You can find a copy on Loot if you’re in South Africa, otherwise here or here.