Wild Ocean Blue

The Pacific island nation, Palau, has announced a ban on shark fishing throughout it’s territorial waters. This bold show of commitment to curbing the global shark cull will put over half a million square km of ocean off limits to shark fishing. That’s an area slightly smaller than the whole of France.

In recent years we hear little but bad news about sharks. As experts work their way through the species, virtually every one is assigned a label of endangerment on the IUCN Red List, ranging from near threatened to critically endangered.

So is this at last some good news for sharks?

Young tiger shark (c) Terry Goss 2007/Marine Photobank

Surely yes, it is. It doesn’t matter one bit that Palau’s decision was sweetened by the prospect of tourist dollars pouring in from scuba divers desperate for shark encounters. Perhaps all the better that recognition is growing of the alternative price tag sharks carry, rather than as simply a pile of meat, cartilage and fins.

But I can’t help worrying about that enormous area of ocean we are talking about here in a region famous for it’s abundant shark populations. Does Palau have the resources to police such a vast area? How can they possibly keep out illegal fishing boats?

There’s no doubt that Palau are going to need some help if this is to be anything but a marine reserve on paper.

Other countries need to take steps to help stamp out illegal shark fishing and work out ways of cutting down the number of sharks killed unintentionally every year by long-lining and trawl fisheries.

One relatively straight-forward solution – or part of the solution – would be a world-wide ban on landing fins that are not accompanied by the sharks they grew on.

A shark thrown back without its fins. Nancy Boucha, www.scubasystems.org 2005/Marine Photobank

The greatest incentive for shark fishing these days is to sell their valuable fins into the shark fin soup trade. Forcing fishermen to give up at-sea finning could help cut down the number that of sharks are killed every year. A single boat can carry thousands of fins, but far fewer whole shark carcasses.

Pile of shark fins. Jessica King/Marine Photobank

President of Palau, Johnson Toribiong, told BBC News “…the need to protect the sharks outweighs the need to enjoy a bowl of soup.”

Absolutely it does.

Whatever happens next, Palau has made a radical and admirable step in declaring shark fishing out of bounds. It raises the bar in terms of the level of commitment we need to see all around the world if the oceans are to be anywhere near as shark-infested as they should be.

On this week’s Naked Scientists we had behavioural ecologist Rebecca Kilner in the studio telling us about the extraordinary things cuckoos get up to. Duping other species into rearing your babies for you is undeniably a crafty way of going about life. But it’s not just cuckoos that do it, she told us. Fish do it too.

Namely the cuckoo catfish, a beautiful spotty fish from Lake Tanganyika.

Cuckoo Catfish. Photo by Johnny Jensen

Obviously, its name is a bit of a giveaway. And yes, technically this is a freshwater species – not an ocean inhabitant – but I was so amazed when I found out more about this fish that I decided they deserve space on wild ocean blue (and don’t they look a bit like goat fish?).

For starters, cuckoo catfish hang around cichlids, those famously diverse inhabitants of the great lakes of the African Rift Valley. And they get rather excited by the sight and smell of mating cichlids. So excited in fact, that male and female catfish rush in and cast their own eggs and sperm among the cichlid eggs on the lake floor (where they live as far down as 100m below the surface). The catfish also gobble up a few of the cichlid eggs while they are at it.

Lake Tanganyika as seen from space

The unlucky cichlids are mouth brooders, which means that seconds after the eggs are fertilized the female cichlid slurps them all up and incubates them inside her mouth. Cichlids can’t distinguish their own eggs from the impostors’ so they all get scooped up together.

Can she still eat with a mouth full of growing babies? Apparently not very well. By the time the babies have vacated their mother’s mouth, they  leave her underweight and hungry.

And it is not simply that the wily catfish leave their young in the care of the cichlids. They go one step further.

The cuckoo catfish young have evolved to hatch earlier than the cichlids. When they do, they instinctively eat the cichlid eggs and any cichlid fry that have hatched, eventually leaving nothing but catfish fry in the duped cichlid’s mouth.

The cichlid mother is so oblivious to the fraudsters she is nurturing that she will suck the young catfish back into her mouth if they wander outside.

Cuckoo Catfish. Photo by Johnny Jensen

Cuckoo catfish are popular with aquarium keepers, who have discovered that they don’t have to pass their eggs on to cichlids. Their eggs get on perfectly well if they are simply laid on their own on the tank floor.

why, why, why?

It might like seem like a foolish plan to trust your offspring to a total stranger. Imagine the human equivalent! But it obviously does make sense because so-called brood parasitism has evolved in several different groups of animals.

And the reason it works is because for many animals raising youngsters is difficult and costly: feeding them, keeping them safe without risking your own neck, all sorts.

So even if you occasionally get caught out, it can pay off in the long run to palm your babies off on someone else while you head off and make more babies elsewhere.

I give you the cuckoo catfish. All in all, a crazy and wonderful animal. And yet another perfect example of natural selection driving the evolution of something brilliantly adapted to a certain way of life.

In detail:

• Cuckoo catfish, Synodontis multipuncata, can live for up to 15 years.
• Females grow bigger than males, up to about a foot long.
• They are the only fish known to be brood parasites.
• Fishbase entry

Biofuels and the growing areas of ‘dead’ ocean may seem worlds apart.

But a new study warns that boosting biofuel crop production in the US could thwart attempts to reduce the expanse of the northern Gulf of Mexico (GOM) that becomes oxygen-depleted every year.

In 2008, a dead zone the size of Massachusetts (over 27,000 square km) formed in the Gulf of Mexico threatening marine wildlife, fisheries and tourism.

The Mississippi River carrying fertilizers into the Gulf of Mexico

why?

Because much of the fertilizers added to cropland – including biofuels – end up washing into rivers and eventually the ocean, causing a phenomenon known as eutrophication that triggers algal blooms. The algae die and sink to the seabed where they are broken down by bacteria. This uses up available oxygen, something that many marine species rely on. An earlier study in 2008 uncovered just how fast these dead zones are spreading.

what’s new?

A computer model of the southern US under various future scenarios suggests that no-matter what crops are grown – even grasses which require fewer artificial fertilizers – if federal plans to produce 36 billion gallons of biofuel by 2022 come to fruition, there may be little hope of curbing the area of the GOM that becomes seasonally inhospitable to wildlife.

This not only has implications for the US and its surrounding seas but also other countries that are considering boosting biofuel production as a way of trying to combat climate change.

biofuel or no biofuel?

This study undoubtedly adds another strand to the debate over whether biofuels can provide a sustainable solution to carbon dioxide emissions, demonstrating how important it is to consider all the potential ecological consequences of biofuels.

But the authors of this study point out that there are ways that biofuel crop production can be rendered less harmful to the aquatic environment:

• plant vegetation along river courses to promote nutrient uptake
• create wetlands
• promote the precise application of fertilizers.

In detail:

The study, Impact of Biofuel Crop Production on the Formation of Hypoxia in the Gulf of Mexico by Costello et al is published in the journal of Environmental Science and Technology.

Last night I attended this year’s Galapagos Day talk at the Royal Geographical Society in London.

And what with this being the 200th anniversary of Charles Darwin’s birth, and 150 years since he completed On the Origin of Species, it is obviously quite an exciting year for the group of islands he made so very famous.

Satellite image of the Galapagos Islands

Guest speakers were Sir David Attenborough (who sat all evening next to a beautiful giant photograph of a seahorse!) and Felipe Cruz (from the Charles Darwin Foundation). In the chair was Andrew Marr.

In an animated half-hour discussion, these three reflected on what makes Galapagos so special and the problems the archipelago faces today.

Sir David spoke of how Galapagos – thanks to its geographic isolation – is ‘a geological world without humanity’. Human visitors to the islands are alien observers, perhaps like no-where else on earth. And the archipelago is all the more magical for it.

In front of a packed audience, virtually all who have visited Galapagos, the speakers tackled the thorny issue of who should be allowed to go to the hallowed archipelago.

Cruz believes that restricted numbers of high-paying tourists is the only way to make Galapagos tourism work. Forget huge cruise ships. Sailing boats are the way to go.

Marr was concerned this would cut out the young, idealistic people – like Darwin himself, perhaps – for who Galapagos could be a great source of inspiration.

Cruz’s solution was to offer scholarships to the brainiest kids.

Unfortunately, Sir David admitted, ‘we can’t all go to Galapagos’. What’s most important is protecting the islands.

All three agreed on the importance of Lonesome George – the last known Pinta Island tortoise, a subspecies of the giant Galapagos tortoise – as a Galapagos icon for us all to reflect on. With George we are staring extinction in the eye.

I was thrilled when Andrew Marr steered the conversation towards the bits of the Galapagos that lie underwater.

Being a barren volcanic outcrop, everything on Galapagos comes from the sea, Sir David told us. The sea birds eat fish, their guano fertilises the plants, and so on.

‘So, if something goes wrong in the ocean, Galapagos is heading for catastrophe,’ Sir David said, reminding us that it’s not just the local issues that must be addressed but the global problems of climate change and ocean acidification.

Marr revealed his love of the oceans, when he admitted that the recent studies predicting that the world’s coral reefs may be wiped out within a few decades, was ‘the most depressing piece of journalism I’ve ever read’.

Sir David echoed some ideas I wrote about in my book Poseidon’s Steed, mentioning a paradox of our modern world, namely, that we know more about the natural world than ever before, and yet we are also more cut off from nature than we ever have been.

If we make the mistake of thinking that we are independent of the natural world, then we are heading, very swiftly, for disaster.

I couldn’t agree more.

Galapagos marine iguana

Then, on a lighter note, the speakers were asked by a member of the audience to name their favourite Galapagos species. Marr chose the boobies. Cruz picked Galapagos petrels. Sir David picked the marine iguanas, because there is ‘nothing like them in the world’

‘Except for the spitting,’ added Marr to a tittering audience.

‘It’s a nasal discharge!’ Sir David corrected him.

In detail:

Tomorrow I’ll be attending the annual Galapagos Day talk at the Royal Geographical Society, hosted by the Galapagos Conservation Trust. I look forward to hearing what the guest speakers Sir David Attenborough, Andrew Marr and Felipe Cruz have to say about the status and future of the islands, including the underwater world.

And hopefully it won’t be all doom and gloom. Just last week, some good news shone through from Galapagos with the discovery of several new coral species including one that was thought to have been wiped out by the 1997-98 coral bleaching event.

Perhaps reefs are more resilient to rising temperatures and coral bleaching than we previously thought?

Bleaching coral inside the Galapagos Marine Reserve. David Jacobsen-Fried/Marine Photobank

Symbiotic algae living inside corals in the Galapagos are showing signs of thermal tolerance, thanks to studies since 1998 by Andrew Baker of the Rosenstiel School of Marine and Atmospheric Science in Miami.

The 3-year Darwin Initiative study brought researchers to the northern Wolf and Darwin Islands for the first time since the 1970s.

Team leader Terry Dawson, from Southampton University, has plans to return to Galapagos on the trail of a gaggle of magnificent pelagic species – including whale sharks and hammerhead sharks.

Could it be that these and other marine migrants are cruising an oceanic highway across the eastern reaches of the Pacific, between Cocos Island off Costa Rica through to the Las Perlas and Coiba Islands in Panama and Malpelo Island off Columbia? Dawson and his team hope to find out.

You can follow up on the latest results of the Galapagos coral reef surveys in the journal Galapagos Research.

They say ‘eat more fish’.  And we are.

But with dwindling populations of large, tasty wild fishes, we are now getting more than half of our global annual omega-3 fix from fish farms.

So says a study in the journal PNAS, by a team of researchers led by Rosamond Naylor from Stanford University in the US.

Wild fish catch in Sabah, Malaysia by Helen Scales

Are farmed fishes a problem? They are when they are fed on the millions of tiny fish that are scraped up from the seabed every year and made into fishmeal and fish oils.

And most farmed fish (and crustaceans) are avid fish-eaters. That goes for shrimp, salmon, tuna and many of our favourite eats.

For every kilo of salmon on the supermarket shelves, around 5 kilos of smaller wild fish are used (or 1 to 5 pounds for US readers!).

Far from taking pressure off wild populations, this merely shifts the focus of exploitation to a different point in the oceanic food web.

Can’t we eat vegetarian fish instead? Well yes, we can. Tilapia and Chinese carp are traditionally raised on plants.

But (why is there always a but?), since the early nineties, fish farmers – including many in China – have begun boosting yields by adding fishmeal to tilapia and carp diets.

Now, at a global scale, farms rearing vegetarian fish use more fishmeal than shrimp and salmon farms combined.

So, is there an answer to this fishy issue? Clearly health-conscious seafood lovers will still want their fish.

Naylor and colleagues recommend that the amount of fishmeal used by fish farms could be cut down without harming the product or productivity too much.

Part of the solution will be tighter regulations on fisheries that contribute to fishmeal production, like anchovies and sardines.

And there could also soon be alternatives to fishmeal and fish oil on the market, including extracts from grains, live-stock by-products, as well as GM plants and microorganisms that could be harvested for that all-important long-chain omega-3 fatty acid.

Hello everyone and welcome to my blog.

I’ve named this site wild ocean blue after the personal website I ran for years (until helenscales.com took it’s place). My plan is to post up-to-the-minute snapshots from the marine world – scientific studies, conservation programmes, photographs etc – that encapsulate the diversity, fragility & beauty of the oceans.

Ultimately, I hope this site will go some way towards answering the question: Why do the oceans matter?

And in addition, now that my first book has been published, I will also put on my writers’ hat and cast a literary eye over the oceans to hunt down other people’s words – both old and new – about the marine realm.

I will begin by offering up what I think are the some of most interesting and important aquatic papers being published (in particular, ones that aren’t making it into the wider press), and then I will take it from there.

Your thoughts and ideas are always most welcome. Thank you for visiting and I do hope you enjoy reading my blog.

All best wishes,

Helen