Lion’s manes, invisible barnacles, suicidal fish, and photoshop hoaxes

It’s definitely summer and the sea has seasons, too. With summer comes the dread of Hong Kong’s beach-goers, the season of the lion’s mane jellyfish Cyanea nozakii.
This large, flat-topped jellyfish can grow to 50 cm in width with 8 bunches of 70 to 120 stinging tentacles that can trail up to 10 m. These tentacles can still sting even when they break off or are torn from the main body (though they lose potency over time).
It is cream to pale yellow with a darker centre and transparent on the outside edge.

A lion’s mane jellyfish (Cyanea nozakii) drifts close to the surface off Lantau Island.

You start to see these guys arrive from late March onwards and they reach their peak in mid-summer and decline in numbers after that.

Although it occurs all over the Indo-Pacific, seasonal outbreaks of the lion’s mane occur in the Yellow and East China seas and the Gulf of Bohai where fisherman regard them as a nuisance : first because they clog up nets and even damage them, second because their presence is linked to the decline of the edible jellyfish Rhopilema esculentum. Although it used to appear sporadically in those areas, it seems to have become more and more of a problem. One Chinese researcher even said that more harm and damage was caused to the coastal waters of China by this species than by red tides. Personally I have not noticed any change in Hong Kong over the years, but maybe I am wrong. When I was a kid (in the 80’s) I remember trying to count the number of jellyfish we passed off Lamma Island in our boat and lost count after 100 in 5 minutes…on average adults weigh about 1.2-1.3 kg so we passed literally a tonne of jellyfish in 5 minutes (and it was a slow boat).
So what about the barnacle and the suicidal fish?
Well, remember symbiosis from high school biology? The jellyfish are sometimes accompanies by other creatures taking advantage of the bad-ass protection offered by the stinging tentacles. One interesting guy is a transparent, soft barnacle called Alepas pacifica that hitches a ride by attaching itself to the outer rim of the jelly’s bell with a stalk and spends the rest of its life in care free existence filter feeding particles out of the water – not a care in the world. Until the jellyfish dies, then it will, too.

Three Jellyfish Barnacles (Alepas pacifica) attached to a jellyfish.

And the other two creatures are two commercial fish: the Razorbelly Scad (Alepes kleinii) and the Malabar Trevally (Caranx malabaricus). Both fish as juveniles like to seek out a lion’s mane soon after they hatch from eggs which – with perfect timing – seems to coincide with the arrival of the jellyfish. Hanging around the jellyfish gives them protection from predators. Think this is perfect adaptation? You would be wrong. The fish might gain an advantage from hiding by the jellyfish but they have not evolved any mechanism to avoid or deal with the stinging tentacles! Think of a child hiding from the bogeyman on top of a high voltage electricity pylon and you get a good idea of the risk to the fish. They have to swim very, very carefully! And on top of all that they are very loyal or attached to this dangerous fortress, too. When a jellyfish are caught and handled the fish stay with the jellyfish until inevitably they are forced into contact with the tentacles and are repeatedly stung until the die. Suicidal fish.

You can find more information on Hong Kong marine symbiosis in the book “Partnerships in the Sea: Hong Kong’s Marine Symbiosis” by Brian Morton.

An adult razorbelly scad (Alepes kleinii).
An adult Malabar Trevally (Caranx malabaricus). As juveniles they use the lion’s mane for protection from predators.

And now – sex:

Jellyfish can reproduce sexually and asexually. And when they chose sex it’s between male and female jellyfish – not that you can tell the difference unless you have a microscope and a lot of time. But like most invertebrates they simply try to time their spontaneous ejection of sperm and eggs into the water and hope that some meet, fertilise and grow into larvae. The microscopic larvae, called planula, are tiny, hairy, slipper-shaped things that use their tiny hairs (called cilia) to propel themselves. The planula larvae  of the lion’s mane only last a day and a half before they settle on the seabed and turn into small polyps like coral except solitary instead of in big colonies. After that they bud off little 2-3 mm wide jellyfish which then grow into the adult 20-30 cm wide jellyfish we all fear coming into contact with while swimming.

The life cycle of a jellyfish. Staring from planula larvae (1) to adult medusa (14). (From Schleiden M. J. "Die Entwicklung der Meduse". In: "Das Meer", A. Sacco Nachf., Berlin, 1869.)
The life cycle of a jellyfish. Staring from planula larvae (1) to adult medusa (14). (From Schleiden M. J. “Die Entwicklung der Meduse”. In: “Das Meer”, A. Sacco Nachf., Berlin, 1869.)

Photoshop hoax:

Some time ago the below image circulated online of a gigantic lions mane jellyfish dwarfing a diver.  This is actually a different species (Cyanea capillata) to our lions mane (Cyanea nozakii) even though it shares the same common name. Thanks to Google’s reverse image search the image was quickly exposed as a photoshopped fake as you can read in this Forbes article .

Photoshoped image of a lions mane jellyfish with a diver. L=Impressive sight, sadly a fake.
Photoshoped image of a lion’s mane jellyfish with a diver. L=Impressive sight, sadly a fake.
And finally some interesting recent research on the lion’s mane jellyfish:

– Researchers in Qingdao investigating the venom of the stinging tentacles found it was most stable for storage at -80 degrees Celsius and that it was more effective at killing human colon cancer cells compared with human liver cancer cells.

– Researchers in Lianyungang attempting to find some sort of use for the enormous unwanted by catch of lions manes in fisheries found that it is a good source of collagen and that compared to other sources of collagen it had lower levels of arsenic, mercury and lead.

– Researchers in Japan have tried to isolate the gene responsible for the lions manes production of an enzyme called endoglycoceramidase which is useful in synthesising some other molecules. Also in Japan researchers worked on the acoustic signature of different jellyfish species to develop an avoidance system for fishing boats. The acoustic signature is essentially the characteristics of the echo received from a pinger when the sound waves hit the jellyfish. Unfortunately they were not able to tell jellyfish species apart , which would have been a wonderful way to quickly measure their populations by just towing a pinger over a vast area and then estimating the population from the echo data.


Red Tides, Fish Kills and iPhone Apps

Here are some images of some pretty right red tide patches. But what on earth is it that makes the water go red like this and is it dangerous?

red tide in DB
Floating patch of red tide in Discovery Bay 4/6/2014

Red tide is the collective name for phytoplankton blooms that tend to colour the water. Phytoplankton is made up of microscopic plants that drift through the sea. When conditions are right (mostly when there is nutrient-rich water and a stable water column) some species of these micro-algae form red tides. Depending on the pigments, the massive growth of algal cells may turn the water into pink, red, brown, reddish-brown, deep green or other colours.

"Pink" Red Tide on Tai Pak Beach
“Pink” Red Tide washing ashore on Tai Pak Beach in Discovery Bay 4/6/2014


Red tides are a relatively common sight in Hong Kong with 20-30 reports a year. The immediate reaction from most people is to think that they are the result of some terrible pollution. In fact the phytoplankton species are perfectly natural and normally occur in Hong Kong waters, but under certain conditions they can grow faster and form patches on the sea surface which we call ‘blooms’. Phytoplankton blooms by different species occur all over the world and are often seen by satellites with colour sensors.

Bloom of the phytoplankton species Emiliania huxleyi in the English Channel as seen from space by a satellite. The light blue comes from the seawater and the white calcium shell of the algal species.

Some red tides produce natural toxins, and can cause depletion of dissolved oxygen or other harmful effects, and are generally described as harmful algal blooms (HAB). The most conspicuous effects of these kinds of red tides are the deaths of marine and coastal species of fish, birds, marine mammals, and other organisms. This happens either as a direct effect of the toxins produced or because of oxygen depletion (known as hypoxia) which happens when the algae die and bacteria consume all the oxygen in decomposing the dead algae.
Only some species involved in red tides however are toxin-producing and cause fish kills. The bioluminescing species Noctiluca scintillans which I wrote about in an earlier post, is not toxic but still can cause red tides.
For Hong Kong this is an economic concern because of the many fish farms and aquaculture areas. When a toxic red tide drifts into a fish farming zone only early warning will help the farmers avoid large economic losses from fish kills by temporarily evacuating their fish cages or transferring their fish to tanks.
The Agriculture, Fisheries & Conservation Department (AFCD) of Hong Kong runs a red tide monitoring network which relies partly on fish farmers and members of the public.  The AFCD follows up reports by taking samples from the red tides and identifying the contributing species under the microscope to determine the risk to aquaculturists and the public. The majority of the reports are caused by non-toxic species. If you would like to know more about the network, the AFCD now has a fantatsitc  app for iPhone and Android (pictured below) with weekly updates and the functionality to report red tide sightings (which I proudly did today) with this new app, including submitting  pictures. (I would also recommend some of the other Hong Kong apps for marine enthusiasts out there:  HK Geopark, Wetland Park, Reef Check, Red Tide Information Network and the WWF Seafood Guide).


The AFCD’s “Red Tide” App for iPhone (also for Android). You can get weekly updates and also report red tide sightings. Available in Chinese (traditional and simpliefied) and English.


The AFCD started to record the occurrences of red tide since 1975. From 1975 to 2013, a total of 875 red tide incidents were recorded in Hong Kong waters. Amongst these incidents, only 27 were associated with fish kills.

77 algal species have formed red tides in Hong Kong, but majority of them are harmless. 19 of these species are considered harmful or toxic. Amongst these harmful/toxic algal species, only 5 of them caused fish kills and the other two caused contamination of shellfish by toxin in Hong Kong. The red tide associated fish kill events were mostly recorded in the 80’s and early 90’s.

So are there dangers to human health? If a red tide is identified as a harmful algal bloom (HAB) – then, yes, there is a risk:
The consumption of shellfish (e.g. mussels, clams) is one of the most common ways for algal toxins to impact human health. Each species has it’s own toxin so the health effects they cause are also varied. One example is Ciguatera fish poisoning. This type of fish poisoning is caused by eating fish that contain toxins produced by a the marine microalgae Gambierdiscus toxicus, which has been recorded in Hong Kong waters. Barracuda, black grouper,blackfin snapper, king mackerel, groupers and any large predatory fish can carryciguatoxins. People who haveciguatera may experience nausea, vomiting, and neurologic symptoms such as tingling fingers or toes. They also may find that cold things feel hot and hot things feel cold.Ciguatera has no cure. Symptoms usually go away in days or weeks but can last for years. People who haveciguateracan be treated for their symptoms. In Hong Kong with its rapacious appetite for seafood, ciguatera fish poisoning occurs quite frequently. For example, in 2004 it made up 7.9% of all food poisoning cases recorded that year. In June 2013, fourteen men and five women, aged 23 to 71, fell ill with ciguatera poisoning after eating coral reef fish at a restaurant in Sok Kwu Wan (Lamma Island). The fish in this case actually came from the Pratas/Dongsha Islands out in the South China Sea. Ciguatoxin’s is very stable, so cooking, drying or refrigerating fish will not destroy the poison. There is also no effective way to test fish for ciguatoxin, yet. If you want to play it safe avoid large predatory fish like tuna, grouper and others alltogether (they are mostly overfished already, especially blue-fin tuna, so you would be doing the planet a big favor).

So eating shellfish or fish which has been exposed to HABs is the main danger to humans. There are instances of skin irritations and breathing difficulties after direct human exposure to HABs but these are rarer and not as well understood. So to be absolutely safe, I would advise you to avoid contact with red tides – no swimming in, diving under or touching them!

Toxic Algae and Man-Sized Jellyfish

Once a swampy backwater of fewer than 20 million people, the Pearl River Delta—the southern swath of mainland China above Hong Kong—now has three times that population. Tens of millions more humans in the Pearl River Delta means many more toilets a-flush, pumping a steady gush of human waste into the South China Sea.
Read the full story at Quartz

SCMP: Mainland sewage fuelling Hong Kong’s ‘red tides’

According to the SCMP, sewage from the mainland is fuelling an increase of harmful algal blooms – known as red tides – in Hong Kong waters.

Professor Ho Kin-chung, dean of the Open University’s school of science and technology and an expert on algae, told the SCMP the red tides were “fed” by nutrients flowing in from mainland waters to the east and west of Hong Kong.

“The economic boom across the border leads to more sewage discharge into the sea and rivers, and in the right seasons [the nutrients] come down to us. So this is no longer a local phenomenon but a regional one,” Ho said.

Within the last fortnight brown algae been spotted across the territory – off Lamma Island, Cheung Chau, Lantau and within Victoria Harbour.

Agriculture, Fisheries and Conservation Department staff said they had spotted red tides at fish culture zones within Tolo Harbour, Sha Tau Kok and Tai Mei Tuk, while a member of the public reported another at Pak Sha Wan in Sai Kung.

Most algae absorb nutrients such as phosphates or nitrates that are commonly found in cities’ wastewater. At the right temperature, well-fed algae will proliferate in a short period of time.

Ho said Hong Kong was sandwiched by the Pearl River in the west and Mirs Bay in the east and these were the two key origins of red tides in local waters.

As a result, Tuen Mun, Lantau, Tolo Harbour and Sai Kung were becoming increasingly prone to the phenomenon.

Recent reports of large amounts of seaweed being washed onto beaches in South Lantau should not be confused with red tides. Red tides are composed of free-floating (planktonic) algae, seaweed however are larger marine plants normally growing attached to the seabed, reefs or rocks.

A spokeswoman for the Agriculture, Fisheries and Conservation Department said it would announce today whether tests had found the algae off Lamma Island to be toxic.

Four red tides were also spotted in Hong Kong waters last week.
Three red tides at fish culture zones within Tolo Harbour, Sha Tau Kok fish culture zone and Tai Mei Tuk were observed by staff members of the Agriculture, Fisheries and Conservation Department (AFCD) during April 8 to 10. Another red tide was spotted on April 9 by a member of the public at Pak Sha Wan, Sai Kung.

None of the red tides were associated with the death of fish in these occurrences.  “The red tides at fish culture zones within Tolo Harbour and Tai Mei Tuk were formed by Gonyaulax polygramma, Prorocentrum minimum and Heterosigma akashiwo. The one at Pak Sha Wan, Sai Kung, was formed by Gonyaulax polygramma whereas the one at Sha Tau Kok fish culture zone was formed by Heterosigma akashiwo and Prorocentrum minimum. All the above algal blooms are commonly found in Hong Kong waters. Gonyaulax polygramma and Heterosigma akashiwo are non-toxic. Studies have shown that Prorocentrum minimum may produce toxin, but no such reports or associated fish kills have been recorded in Hong Kong,” a spokesman for the working group said.

Red tides are a natural phenomenon. The AFCD’s phytoplankton monitoring programme will continue monitoring red tide occurrences to minimise the impact on the mariculture industry and the public.

In 1998, a red tide killed 80 per cent of the stock at Hong Kong fish farms.

 Source: SCMP 17/04/2014 and AFCD Press Release 11/04/2014

Beach Blobs

Recently a reader sent me some pictures of yellowy-green blobs at Pui O beach and asked me if I knew what they could be. Beach blobs turn up on beaches all over the world and are actually a pretty interesting topic. Type ‘beach blob’ into a google image search and you will find a range of blobs from tiny and inconspicuous to giant and downright frightening blobs.


Blobs can be or be produced by any number of organisms including the egg cases of marine polychaete worms, dead jellyfish and any number of other partly decomposing marine animals.

After I looked at the pictures closely it seemed to me these particular blobs are most likely the remains of small jellyfish. The tentacles have either already decomposed and broken off or we’re very tiny to begin with. Only the “bell” is left.  The bell of the jellyfish is made of two firm layers of skin-like tissue sandwiching a layer of connective tissue called mesoglea. 

This mesoglea is a translucent, non-living, jelly-like substance  and is mostly water. Other than water, it contains several other substances including fibrous proteins like collagen. The mesoglea also contains muscle bundles and nerve fibres. It acts like an internal skeleton, supporting the bell and its elastic properties help restore the shape after it is deformed by the contraction of muscles when the jellyfish swims. If you have ever watched a jellyfish swim you’ll know it moves by opening and flattening the bell to draw water in, followed by contracting and closing of the bell to expel the water.
When I zoomed in on the pictures I could just make out 4 faint circular structures arranged in a cross in the middle of some of the blobs. These I am pretty sure are the gonads or sex organs of the jellyfish.

Anatomy of a jellyfish

The gonads are the cross-shaped circle-like structure in the center of this jellyfish.
The gonads are the cross-shaped circle-like structure in the center of this jellyfish.

Look very very closely and you may be able to spot 4 tiny circle outlines inside some of the yellow-green blobs. These are the gonads or sex organs of the jellyfish.

Unfortunately without the actual blobs in my hand or under a microscope I can’t say anymore than that. Jellyfish come in all sorts of sizes from microscopic to more than 2 m across so these could be juveniles or they could be adults.

Thanks to my reader for sending me this fun little mystery. If anyone else out there has any mystery pics that need identifying, please leave a comment and I’ll get in touch.

Global Citizen Science – Introducing the Secchi App

Screenshots of the Secchi App
Screenshots of the Secchi App

SecchiApp2Calling all budding marine biologists!
The University of Plymouth has developed an app that let’s you directly contribute to science by recording phytoplankton densities with the aid of a simple device called a Secchi disk – which you can make at home – and their free iPhone or Android app.
Phytoplankton are tiny floating algae that soak up carbon dioxide and nutrients and use sunlight to convert them into carbohydrates, proteins and fats to grow and release oxygen at the same time. Phytoplankton is very important for climate change because when they die they settle down to the sea bed either directly or by being eaten and then pooped out by animals. This process of binding carbon dioxide from the ocean and burying it layer upon layer of sediment on the ocean floor is often called a carbon sink.
Quite apart from this phytoplankton is also the basis of the marine food chain, so almost all other ocean creatures depend on it.
But many researchers have claimed to find a decrease in phytoplankton levels. But now you can help in what may become the worlds biggest phytoplankton study and help find out what is really happening with phytoplankton worldwide.
The app shoes you how to make a simple device called a Secchi disk – basically a flat circular disk lowers into the water by a rope. You then lower thie disk down into the water until it just disappears from view and record this depth – this is the ‘Secchi depth’. So basically you are measuring underwater visability in the vertical dimension.

how a secchi disk works
The Secchi disk measures the visibility of the water column in the vertical plane and this measurement serves as a crude measure of plankton density.

This is a so-called proxy for phytoplankton density in the water – it’s not the actual measurement of phytoplankton density but a measurement that is very strongly correlated to it, because phytoplankton is the main cause of visibility levels. So by measuring the visibility we can indirectly infer how dense the phytoplankton is in the water.
The app has full instructions on how to make a Secchi disk and how to make the measurements. So if you have access to a boat, download the app, and get busy as doing some ‘citizen marine biology’!

A brief history of marine flesh-eating disease in Hong Kong

Flesh-eating disease – or necrotizing fasciitis as its known medically – is fast, nasty and often fatal. The fact that you can get it from contact with seawater makes it even more scary! Should we not swim in the sea anymore? Avoid all seafood? Stay away from beaches, boats and wet markets? These are the sort of questions raised recently. This thread from concerned residents on the Discovery Bay Forum is a good example.

But hold on a minute! The case discussed in the forum actually turned out to have nothing at all do with beaches, seawater, shellfish fish or anything else marine. A common Streptococcus bacteria which lives all around us on our bodies and in our guts was the cause of that infection.

So don’t panic! It’s a fascinating topic, and I want to look at the facts and the data first and then bring things into perspective with a look at the history of marine flesh-eating disease in Hong kong. What exactly is the danger? How worried should we be?

What is flesh-eating disease?
It is a serious bacterial infection of the soft tissue. The bacteria don’t actually eat flesh but the toxins they release while multiplying kill off living cells around them. This can cause death within 12 and 24 hours and about 20 to 30 percent of cases are fatal.

Several different bacteria can cause it. The most common cause is group A Streptococcus, which lives in people’s throats or on their skin. The man in Discovery Bay who recently died actually contracted a type of Streptococcus. But other bacteria can also cause it, including some which naturally live in your guts, on your skin, in marine sediment and seawater, soil, decaying plants and other places. One type called methicillin-restistant Staphylococcus aureus – best known from the news as MRSA – has also become important in the last 10 years because it is resistant to almost all antibiotics and is a major problem in hospitals. And it doesn’t have to be one type of bacteria that causes flesh-eating disease, they can also act together in what is known as Type II or polymicrobial necrotizing fasciitis.

So you can’t avoid these bacteria as they are everywhere in the environment. However, to cause an infection with flesh-eating disease they need a way into your body, because skin will not let them in, but an open wound will give them a chance to grow. Even once inside, your immune system is a great defence, as long as the bacteria do not enter your bloodstream directly. The majority of reported cases are in people who for several possible reasons have a weakened immune system: e.g. underlying illness, chronic diseases, tumours, diabetes, alcoholism or immuno-surpressing drugs and these cases are most likely to be fatal if the infection enters the blood stream. In fact one of the test of Vibrio vulnificus involves injecting the bacteria into the blood stream of mice to see if they die….sometimes science is a bit grim…but still, it saves lives.

Most but not all of the cases reported in Hong Kong recently were all caused by a marine bacteria Vibrio vulnificus, a relative of the bacteria that causes cholera (Vibrio cholerae).

What is the danger from Vibrio vulnificus?

The bacterium is everywhere, both geographically and in a variety of environments, although it occurs in relatively low numbers. It is naturally present in warm seawater and is not linked to pollution, although some studies have found higher numbers of this bacteria in tar balls (e.g. washed up tar balls from the Deep-water Horizon Oil spill), which attract many kinds of bacteria. It likes brackish (mixed fresh and seawater) and so is more common in estuaries and near river mouths. Because it likes warm water, it is more common in the summer months. Infection occurs through open wounds or through eating raw or undercooked shellfish or fish, but is not transmissible between persons. Anyone can be affected by wound infections, but persons with underlying medical conditions, especially liver disease, are at increased risk of blood stream infection and serious complications.

Vibrio vulnificus infections happen worldwide: the US, Japan, Southern Europe etc. In Taiwan, an annual number of 13-26 cases were reported during 1996-2000. The incubation period is usually 12 to 72 hours and the symptoms are intense pain, redness, swelling and rapidly developing tissue destruction usually associated with some form of wound. In persons with underlying medical conditions, especially liver disease, it can cause bloodstream infections with fever, chills, decreased blood pressure, blistering skin lesions and even death in severe cases. In healthy persons, it can cause diarrhoea, vomiting and abdominal pain. Sometimes, the swelling starts at the site of minor injury such as a small cut or bruise, but in other cases there is no obvious source of infection. Bloodstream infections in persons with liver disease are fatal about 50% of the time.

The infection is treated with antibiotics to kill the bacteria as soon as possible, but patients may also need surgery to cut away infected dead tissue or amputate the affected limb. Other than that, those who recover suffer no long-term consequences.

What is the dangerous it in Hong Kong?

In the last 7 years (since May 2005), there have been 51 reported cases of Vibrio vulnificus infections in Hong Kong – 37 Men and 14 women – an average of about 7 cases a year. To put this into perspective, in 2011 there were 6 reported cases of leprosy and in 2010 there were 124 reported snake bites in Hong Kong.

Infections occur predominantly in the summer months from May to October when the water is warm and conditions are right. Isolated cases also appear in colder months, but this could simply be because fish or shellfish is often kept in warmer tanks or because fresh seafood is now globally traded and flown  around the world and imported from warmer regions.

Reported Vibrio vulnificus infections in Hong Kong 2005-2012
Seasonal pattern of reported Vibrio vulnificus infections per month from 2005-2012. Infections peak in July and occur predominantly in the summer months from May to October.

Although the fatality rate is high at 27%, with 32% for men and 14% for women. The average age of infected persons was 66 for men and 71 for women.

From about July 2011 the Department of Health also reported if cases had underlying illnesses, and this shows that at least 53% of cases had underlying illness (3% did not have underlying illness and for the remaining cases the Centre for Health Protection’s press releases did not have enough information). I have compiled the data as a spreadsheet which you can download for free by clicking this link.

So basically, if you are older and/or weakened by illness or chronic disease you are at risk if you suffer a wound from handling seafood or have an open wound that comes into contact with uncooked seafood or seawater. Otherwise, there is no need to worry yourself greatly.

You should of course follow the CHP’s advice on prevention, which is more or less common-sensical:

* Avoid foot/leg contact with dirty water when visiting wet market;
* Avoid exposure of open wounds or broken skin to seawater or salty water;
* Wounds should be thoroughly cleaned and properly covered; and
* Wear thick rubber gloves when handling raw shellfish.
* You should seek medical advice promptly if you develop symptoms and signs of infection such as increasing redness, pain and swelling.

As V. vulnificus is so fond of warm brackish water, consider this: climate change is a leading cause of warming seas around the world, as well as of increased freshwater run-off from more erratic and heavier rain storms caused by the higher evaporation of seawater. This means that one of the effects of climate change could be an increase in infections, because the ideal conditions for V. vulnificus are becoming more widespread. There is a very direct and personal reason to cut your carbon foot-print, especially if you like shellfish and beach holidays…