Bookshelf: The Seabird’s Cry

The Seabird’s Cry: The Lives and Loves of Puffins, Gannets and Other Ocean Voyagers – Adam Nicolson

The Seabird's Cry
The Seabird’s Cry

This is such a wonderful book that I read it twice within the span of six months. In between my two readings, during the northern hemisphere spring, Tony and I visited Pembrokeshire in Wales. This is not the home of Mr Darcy, but rather the location of several islands on which seabirds breed. Seeing puffins, gannets and shearwaters in all their glorious breeding plumage animated Nicolson’s descriptions of their precarious lives. (I do plan to share some photos and details of that visit in future posts.)

Early in this book, Nicolson points out that seabirds are the only creatures on earth that are at home in the water, on land, and in the air. To most of us, albatross are perhaps the most familiar pelagic seabirds – Carl Safina’s Eye of the Albatross both introduced and immortalised these extraordinary ocean wanderers for a popular audience. Nicolson devotes a chapter to each of ten species of seabird, including albatross, and writes with such extraordinary lyricism that at at times it’s possible to mistake this book for something other than popular science.

This blurring of boundaries is quite intentional, and completely revelatory. Rather than sounding pretentious or foolish, as most of us would if we tried to channel Seamus Heaney while summarising scientific papers and interviewing researchers, Nicolson achieves a remarkable feat of science communication. He speaks of the wonder that comes not from ignorance, but from knowledge and understanding, and how powerful a thing it is to know the facts of these animals’ lives.

If the idea of trying to join the worlds of science and poetry (or literature, or culture) grabs you, you may enjoy this video of a conversation on the subject between Adam Nicolson and Tim Birkenhead, a professor of ornithology.

Seabirds are in trouble worldwide, more threatened than any other group of birds. They are facing – amongst others – challenges wrought by changing ecosystems as the climate warms and industrial fishing robs them of their prey. To help them, we need to act, and action comes after seeing and understanding. In this book Nicolson makes an appeal to a part of us other than the rational, fact-collecting, logical entity, and asks us to empathise with these strikingly “other” creatures. I urge you to read this book.

You can read rapturous reviews of this book on The Guardian’s website, on Literary Hub, and at the Financial Times.

Get a copy here (South Africa), or here. It is available for Kindle, but you’ll have to search for that one yourself!

Newsletter: Trawling

Hi divers

Weekend dive plans

No diving

Fishing trawler at work
Fishing trawler at work

Saturday morning looks to be the best time this weekend for a spot of diving. We are heading offshore on a pelagic birding trip / hunt for fishing trawlers which means no inshore diving for us until next week.

regards

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

Diving is addictive!

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Bookshelf: Beachcombing in South Africa

Beachcombing in South Africa – Rudy van der Elst

Beachcombing in South Africa
Beachcombing in South Africa

Why so quiet? What have we been doing? Working, mostly. Trying to stay alive. And a bit of reading, and some beachcombing. Enter this is marvellous little book from fish fundi Rudy van der Elst (A Field Guide to the Common Sea Fishes of South Africa).

Chapter by chapter, van der Elst describes the types of debris that one might find on a beach. After a brief orientation chapter covering the ocean current regime around South Africa, relevant regulations, safety, beach ecology, tides, pollution and more, we launch into a tour of washed-up treasures.

Predictably, many of the items to be found are organic in nature – plants, invertebrates of various types, eggs and egg cases, fishes, birds, and shells. There are also items such as oceanographic devices, tags from marine animals, fishing equipment, cyalumes, buoys – some of these (such as tags) should be returned to their owners, and others should be removed from the vicinity of the ocean (such as discarded fishing nets and lines).

The chapter on marine animals (resting, nesting and stranded) is exceptionally useful and it is almost for this alone that I’d like to put a copy of this book in every home in every coastal town in the country. Seals, whales, turtles and seabirds can end up on the beach, sometimes in difficulty and at other times not. It can be hard to tell, and well-meaning members of the public can unwittingly cause great harm while trying to assist. A list of useful contacts in this regard appears at the end of the book, such as the Two Oceans Aquarium and the SPCA (region-specific).

The final two chapters cover miscellaneous “treasures” such as fossilised sharks teeth, sea glass, logs, and actual treasure, as well as beachcombing through the ages in South Africa. Here we learn about tidal fish traps, coastal caves, and other historical coastal dwellers who made their living from the sea.

We’ve found some awesome things on the beach, from shipwrecks to goose barnacles to rare crabs. Beachcombing is an accessible hobby that requires nothing but time, observation skills, curiosity, and a beach to stroll on.

This is a beautifully illustrated, comprehensive little volume that deserves to come with you on your beach holiday. It’ll prompt more careful examination of the flotsam and jetsam on your local beach, and, probably, more early morning low-tide visits to find the best pickings!

Wild Card magazine featured this book when it was published. Get it online here if you’re in South Africa, or here for your Kindle.

Newsletter: Enough is enough

Hi divers

Weekend dive plans

No diving

There is a week of strong north westerly wind planned for us… Added to this is a fair amount of swell. As a rule wind from this direction will turn False Bay in to a viz wonderland. Once the swell fades, of course! I have no dives planned for this weekend, but I expect conditions next week to be very good.

Diving humpback whale
Diving humpback whale

Octopus fishermen strike again

UNBELIEVABLY, the octopus fishery in False Bay caught and killed another whale this week. If you haven’t signed the petition yet, please do.

Please also send an email to our new minster of Environment, Forestry and Fisheries, Minister Barbara Creecy. She has solicited suggestions for environmental policies that will shape the future of South Africa to the email address DEAMedia@environment.gov.za, and I reckon this is a good place to start.

The City of Cape Town put out an outstanding press release this afternoon calling for an immediate moratorium on the whale – sorry, octopus – fishery, which I encourage you to read. It pulls no punches: “We cannot expect ratepayers to keep on subsidising the bycatch of whales.”

I suggest letting your ward councillors know that this is unacceptable, even more so in a marine protected area, and that you are behind the City’s call to the government to put a stop to the whaling.

You could also send a letter to Herman Oosthuizen, South Africa’s representative (“commissioner“) on the International Whaling Commission. Dig around here for his contact details (a postal address), or try the email address listed on this paper – click on Author Information just under the list of authors’ names. It goes without saying that you need to be polite, reasonable and respectful when you contact people, no matter how emotional this issue makes you.

Abalone poaching – read all about it

Kimon de Greef, author of the outstanding book Poacher along with Shuhood Abader (the pen name of a former perlemoen poacher), will be discussing the subject next Thursday evening, 4 July, at Kalk Bay books. It’s bound to be a very popular event and rsvp is essential. Details here. (We’re reviewing the book on the blog on Monday.)

regards

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

Diving is addictive!

To subscribe to receive this newsletter by email, use the form on this page!

Newsletter: Making a difference

Hi divers

Weekend dive plans

Monday (public holiday): Leaving from  Simons Town at 9.30am and 12.00pm for Atlantis and Photographer’s Reef

We are in  a week long period of practically windless days, not quite winter temperatures and not too much of the dreaded, huge winter swells. You could choose to dive on any of the three days this weekend, or all of them, and I have picked Monday. We will launch from Simons Town at 9.30am and 12.00pm for Atlantis and Photographer’s Reef. Let me know if you’re keen to get out on (and in) False Bay.

Brydes whale showing his head
Brydes whale showing his head

Whale entanglement

It’s been a horrible week. A beautiful Brydes whale became entangled in the ropes of the experimental octopus fishery in False Bay, and drowned. Read about it here (there are some disturbing photos, so take care). In response, there’s a petition to end octopus fishing in False Bay – please sign it.

Can I also encourage you to amplify this issue outside of your usual social networks, who are probably ocean-loving people or friends of ocean lovers, and know about this already. Write an email or call the Department of Environmental Affairs, contact the provincial government, talk to your elected representatives, write to the newspaper. There are some other contact details to be found in one of the links we provided in this newsletter from 2014 that may or may not be useful – sadly this is not a new issue at all.

Beach cleanups

There’s a beach clean up in Cape Town practically every weekend, and it’s fantastic. To find out when they are, follow The Beach Co-Op (facebook / website), and Cape Town Beach Cleanup (facebook / website) to start with. Luckily South Africans are used to doing things themselves, and while the amount of trash recovered is eye-watering, it’s wonderful to see how many people are getting involved with looking after their environment.

regards

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

Diving is addictive!

To subscribe to receive this newsletter by email, use the form on this page!

Hello, Smith’s swimming crab!

One of the things I love about False Bay, and about Long Beach in particular, is the tendency for creatures from all over South Africa’s coastline to end up here, often tropical marine life that got caught in the warm Agulhas current, and then within the circulation of False Bay, ending up just behind the Simons Town harbour wall.

Smith's swimming crab (Charybdis smithii) Smith’s swimming crab (Charybdis smithii)

Thus it was, early in March, that we discovered several adult specimens of Smith’s swimming crab (Charybdis smithii) at Long Beach when we went for a dive. One or two were already dead, and the rest were struggling either on the sand, or in the shallows, looking unhealthy. The water temperature at the time was about 17 degrees.

The first hint that this unusual and rarely-seen visitor had arrived on our shores was a series of social media posts, from January, in one or two of the fishing groups I follow on facebook. (These are excellent places to keep tabs on what’s happening in parts of the ocean I might not routinely visit, and there’s a wealth of knowledge and experience among the members.) Here’s a conversation between local fishermen about seeing large numbers of adult Smith’s swimming crabs just off Cape Point (also facebook). You can also see some photos of one of the crabs from Sea-Change here (facebook), taken on 22 January in False Bay.

Smith's swimming crab (Charybdis smithii) Smith’s swimming crab (Charybdis smithii)

At the same time as these social media posts, there was an influx of small, red crabs on the other side of the Cape Peninsula, at Long Beach in Kommetjie. (But more on that in another post.) Two Oceans says that Smith’s swimming crabs were first described in False Bay in 1838, and then again in 1978, 1983, and 1993. This facebook thread suggests that they may have been last seen off Muizenberg around 2005-2006.

Smith's swimming crab (Charybdis smithii) Smith’s swimming crab (Charybdis smithii)

I read more about Smith’s swimming crab in two papers: this one (Romanov et al), from 2009, and this one (Van Couwelaar et al) from 1997. The more recent paper updates many of the findings of the earlier one. Both teams of scientists behind these papers used trawl data from pelagic cruises to learn about the distribution and life history of these crabs.

Smith’s swimming crab is a pelagic crab that spends the vast majority of its one year, monsoon-driven life cycle in the water column. They are endemic to the western Indian ocean, and are usually found in the area bounded by the Arabian sea (which is west of India) and the latitude of Dar Es Salaam in Tanzania (about 7 degrees south of the equator), and from the east African coast, across east to the Maldives. They may congregate in huge patches, larger than tens of square kilometres, and may reach a biomass of more than 130 kilograms per square kilometre. These swarms are densest between June and September. During July, their concentration can peak at more than 15,000 individuals per square kilometre.

Smith's swimming crab (Charybdis smithii) Smith’s swimming crab (Charybdis smithii)

The crabs congregate on the seafloor of the continental shelf during the months of September to December, mating late in the year. No adult crabs are usually seen between April and June (Van Couwelaar et al speculate that the adults die after breeding), at which time, after metamorphosis, the swarms again become apparent in the western Indian ocean. The crabs grow to about 7.5 centimetres carapace width.

The crabs seem to perform a diel migration, moving deeper in the water column during the day (down to 350 metres’ depth), and returning to the surface at night. They swim continuously and are voracious predators in order to support the high metabolic demand created by this constant activity. They are able to regenerate all their limbs except for their swimming legs (Van Couwelaar et al deduced this in much the same way as Abraham Wald decided which parts of World War II bombers to reinforce – no crabs with partially grown swimming legs were caught in their trawls).

These crabs are important prey for yellowtail, as for other pelagic fish species such as blue sharks, yellowfin tuna and bigeye tuna. The fishermen of False Bay observed that they made excellent bait.

Smith's swimming crab (Charybdis smithii) Smith’s swimming crab (Charybdis smithii)

So what brings Smith’s swimming crab this far south? False Bay is way out of their range. This paper (Chapman, 1988) suggests that prior arrivals of these crabs on our shores have co-incided with weaker than usual summer south easterly winds (which has definitely been a feature of late 2018 and the start of 2019 – we had a gloriously wind-still summer for the most part) and the westward movement of warm water containing the crabs. We did have a spell of unusual westerly wind just prior to these crabs’ arrival.

A fascinating 1984 paper by George Branch describes a temperature anomaly during the summer of 1982-83. This particular Cape summer was characterised by very little of the typical south easterly winds, leading to reduced upwelling, and relatively high sea temperatures (Duffy et al, Effects of the 1982-3 Warm Water Event on the Breeding of South African Seabirds, 1984). The exceptionally warm water on the south and west coasts of South Africa caused mass strandings of some tropical animals (such as portuguese man ‘o war), mortalities of others (such as black mussels), changes in abundance of some species, and extensions of some species’ geographic range. For example, an exceptional number of juvenile turtles washed up on the beaches of False Bay, several months before the usual start of the usual turtle stranding season (which is, very loosely speaking, March-July). Prof Branch records that large numbers of healthy, adult Smith’s swimming crab washed up at Cape Hangklip, and smaller numbers at Boulders Beach, Strand, Milnerton and Blouberg. About 62% of the crabs were female, and many of them survived in aquaria for some time after stranding.

In short, it seems that we had our own little temperature anomlay, however brief, in early 2019, and the pulse of warm water brought with it these rarely seen (in Cape Town) crabs. What luck to spot this unusual visitor!

There are some lovely pictures of Smith’s swimming crab, healthy and in mid water, taken off Tanzania, here.

Bookshelf: Eye of the Shoal

Eye of the Shoal: A Fishwatcher’s Guide to Life, the Ocean and Everything – Helen Scales

Eye of the Shoal
Eye of the Shoal

This is an absolutely wonderful book about fish. Everything about fish. Helen Scales is a marine biologist and the accomplished author of marine-themed books (I previously wrote about Poseidon’s Steedher book about seahorses).

Here, Scales delves into the world of an animal whose variety seems almost without limit. Her book overflows with wonders, and interweaves science, adventure and mythology to shed light on the under-appreciated inhabitants of the underwater realm.

Unsolicited (this is almost always the case), I read half of this book to Tony while I was busy with it, and it delighted both of us. We learned about bioluminescent fish, poisonous fish, the sounds fish make, and the colours of their skin. We learned about fish that use tools, fish cognition, and about the state of the science regarding whether fish experience pain. We even learned about moray eels and grouper hunting co-operatively.

As a scuba diver, Scales relates tales of dives on which she observed the behaviours and phenomena she describes, and I was inspired to pay more attention to the activities of the fish we see on dives around Cape Town. They may (almost) all be the same colour, but there are certainly things that they do, and fascinating ways of being, that I am failing to appreciate.

Scales provides a bibliography on her website with links to the open access scientific papers that she used to research the book.

Get the book here (South Africa), here (US) or here (UK).

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.