The Hong Kong Underwater Photo and Video Competition 2016, jointly organised by the Agriculture, Fisheries and Conservation Department (AFCD) and Hong Kong Underwater Association, announced its winning entries.
The Hong Kong Underwater Photo and Video Competition, in its 5th year now, received 443 entries this year, featuring marine ecology, habitats and marine life in Hong Kong waters.
An AFCD spokesman said, “Entries over the years have showcased the beauty of marine life and habitats in Hong Kong waters, and have helped promote the conservation of the marine environment.”
The event comprised a photo competition and a video competition. In the photo competition the categories were Macros/Close-ups and Standard/Wide Angle. In addition to prizes for champions and runners-up in each group, there were Special Prizes for Junior Underwater Photographers presented by the judging panel to encourage less experienced underwater photographers to participate in the competition.
The venomous Conus textile is one of the most abundant and widespread cone shell in Hong Kong waters. Easily recognized by the tent-shaped markings on the orange-colored cone-shaped shell with wavy chocolates lines, you are advised to stay away from these beautiful but dangerous reef predators. They like to hide in sandy patches under rocks and also occurs widely throughout the Info-Pacific and grow to a maximum of 15cm shell length. The danger they pose comes from a tiny venom-laden harpoon they can fire from their proboscis. They normally use this to hunt other sea snails by injection them with conotoxin through the harpoon-like needle teeth they can fire out of their proboscis. They can reach around to any point on their shell with this proboscis, and several human death have resulted from handling.
To see exactly how subtle and fast the venom injection is, I recommend this clip from YouTube of a textile cone in a tank hunting down a prey snail. The prey snail in the clip has actually sealed itself into its shell and shut the opening with a special door called an operculum – but apparently to no avail!
According to the Facebook page of the HK Juvenile Horseshoe Crab Rearing Programme, juvenile mangrove horseshoe crabs (Carcinoscorpius rotundicauda) were found at Tai Tam during this years HK Bioblitz programme. It is the First record of this species after many years of absence.
A BioBlitz is an intense period of biological surveying in an attempt to record all the living species within a designated area. Groups of scientists, naturalists and volunteers conduct an intensive field study over a continuous time period (e.g., usually 24 hours). This years HK BioBlitz was held at Tai Tam.
The giant clam Tridacna gigas which can grow to 120 in width and 200 kg in weight is one of a group of clams called giant clams – the Tridacnids. Although T. gigas is the biggest of them, there are others which are still pretty huge by clam standards. One of these giant clam species, the Maxima clam Tridacna maxima, used to occur in Hong Kong. It grows to about 40 cm width, though typically is only around 20 cm in width. But consult the IUCN records for this clam species and you will see that although it occurs throughout the tropical and sub-topical waters of the Indian and western Pacific Oceans, the entry for Hong Kong sadly reads ‘regionally extinct’. When did that happen? Why did they vanish? These are the questions I wanted to find answers to.
When did it go ‘regionally extinct’?
The first entry I could find for the Maxima clam being regionally extinct in Hong Kong is 1983. Unfortunately that’s about all I could find. But at it has been gone from Hong Kong since at least 1983. Unless of course it has returned….its a slow-growing animal but has a very wide dispersal through free-floating larvae that live in the plankton – that’s why it occurs over such a wide geographical area spanning nearly a quarter of the planet! So theoretically, if conditions are right (see more below) and larvae are swept over Hong Kong or are purposely introduced by humans, the Maxima clam could reestablish itself in Hong Kong. So the next question is why did it go extinct in Hong Kong in the first place?
What happened to the Maxima clam in Hong Kong?
Apart from the fact that the Maxima clam lived on coral reefs in Hong Kong waters, I can not find any more details of how big the population was, which exact areas in inhabited (obviously coral reefs, so that narrows it to Eastern and Southern Hong Kong waters) or whether it was harvested locally. It is however clear that Hong Kong used to be a big regional market for giant clam species in Asia. Giant clams were and still are a delicacy in Asia (mostly the meat big abductor muscle) and the shell was used for decoration (though not extensively). Even the UN Food and Agriculture Organization has no useful fisheries statistics for Tridacnids. So there is no information on how many – if any – were harvested from Hong Kong waters before they disappeared. The maxima clam like all clams is a filter feeder which suck in water, filters out and swallows edible particles and then ejects the water out again. As such it is quite vulnerable to toxic substances in the water. In addition, it harbors symbiotic microscopic algae called zooxanthellae (zoo-oh-zan-the-lay) in its tissue. These absorb the clams waste products like CO2 and photosynthesize turning them into sugars in the presence of sunlight and giving off oxygen for the clam.
When open, the bright blue, green or brown mantle of the clam is exposed and obscures the edges of the shell which have prominent distinctive furrows. The attractive colours of the mantle are the result of pigment cells, with a crystalline structure inside. These are thought to protect the clam from the effects of intense sunlight, or to bundle light to enhance photosynthesis of the zooxanthellae.
This is essentially what corals do, too, which is why they share the same habitat – coral reefs. And like most reef corals the maxima clam also gets most of its nutrients from its zooxanthellae . Coral reefs suffer enormous damage from smothering by sediment that washes into the sea from rivers and rainfall and from clouding of the water and smothering by excessive algal blooms. Both of these were and still are to some extent big problems for Hong Kong waters, whereas in the past this was not the case. Algal blooms and sediment runoff increased a lot as a result of the increase in human population in Hong Kong and as a result of rapid industrialization and the associated water pollution. This combined with harvesting seems to be the most likely reason for the disappearance of the Maxima clam from Hong Kong waters before 1983.
Will there ever be giant clams in Hong Kong again?
I hope so. Like I said earlier, if conditions are right, any of the wide-ranging planktonic larvae of the clam that stray into Hong Kong waters could settle and grow to adulthood. Failing that humans could also try to establish them by attaching cultured juveniles to appropriate spots on reefs – but this is more complicated and costly, although Singapore has attempted this with initial success using another giant clam species Tridacna squamosa. But the main criteria is suitable conditions for a population to establish and grow – in other words we need clean seas again. Hong Kong has improved a lot on this front up until very recently, when the increased coastal development in southern China started to create a lot of water pollution which somewhat diminishes the results. There is still a long way to go. But I would say that divers should keep an eye out. In fact, the ReefCheck 2015 recorder forms even have a section for giant clams (Tridacna sp.), so its not just me that is hopeful! You never know. you could be diving some coral reef in Sai Kung, Tung Ping Chau, Hoi Ha Wan or the Ninepin Islands and come across a maxima clam. It might be an old dead one stuck in a reef with just the wavy outline of the two shell valves (probably) or it could have the fat, bright blue or green mantle of a live clam – in which case 1) hooray for Hong Kong and 2) please report your finding to the AFCD and Reef Check!
Sea spiders? Sounds like a B-movie horror story: ‘Sharkrantula”, maybe? Not at all. Sea spiders is the common name for pycnogonids (pik-noh-go-nids) which are a type of marine arthropod (joint-legged animal) which includes crustaceans like crabs, lobsters, shrimp and prawns, but also insects. But pycnos have actually got more in common with horseshoe crabs and spiders in terms of anatomy, so the name sea spiders is not too far from the truth.
The occur in seas all over the world from tropical reefs to frozen polar seas and from shallow water to depths of over 7,000 m. Most are tiny although some deep-sea species can grow to 90 cm. Pycnogonids have extremely reduced bodies in which the abdomen has almost disappeared, while the legs are long and clawed. Muscles are in some cases reduced to a single cell! They can even breathe and absorb food through their skin. As you can imagine their dietary needs are therefore very small. And yet they are predators that prey on corals and worms. The head has a long proboscis with an unusual mouth at the end and several simple eyes on a tube-like stalk. The head also has a pair of claws and a pair of attachments on which the eggs can be carried. All in all, it can be very hard to tell just which end of a pycnogonid is the head!
You might think so what? Spiders are creepy and yucky and iffy. But marine biologists love pycnos – they are just so strange and fascinating biologically.
But what has all this got to do with Chinese takeaways And taxonomical jokes?
Earlier this year I received the sad news that the head of the department I used to work in the Natural History Museum in London passed away. Roger Bamber (tribute by Dr. Tammy Horton) was a legend of a man and also an expert on pycnogonids – a pycnogonid taxonomist. Unlike the more familiar taxidermist (who stuffs and preserves dead animals), a taxonomist is an expert on the certain groups of animals or plants and decides what is and is not a new species – but come to think of it and they also work with dead animals and need to preserve them…sometimes they stuff them too…but its much more complex and tricky, I promise. There is a difference honestly!
Anyway, one of Hong Kong’s pycnos (there at least 6 species locally) was discovered by Roger. Tanystylum sinoabductus was identified in Hong Kong’s only marine reserve at Cape D’Aguilar where the Swire Institute of Marine Science is located. (Note: a marine reserve, unlike a marine park, does not allow any sort of anchorage or fishing, so its is completely protected – except for water pollution of course.) This particular pycno was found in exposed mussel beds. But at only roughly 1/2 a mm in size you will only see it with a magnifying glass and only recognize it under a microscope.
And now the for long awaited joke: the species is part of the genus Tanystylum, but the specific (species) name that Roger chose – sinoabductus -is the taxonomical joke. Sino in latin means chinese (duh!), and abductus – if you have not already guessed it – means ‘taken away’, thus sinoabductus is the “Chinese takeaway’. OMG, I hear you say. What an unfunny joke! You have to understand there is not much opportunity for humor in science (except in the pub after the work) and marine biologists spend a long time in the lab staring down a microscope or hours pouring data on a computer and reading and writing scientific papers any chance to get away with even a bit of humor is appreciated!
And just in case anybody in this era of social justice warriors and political correctness thinks that this species name could be racist: the other reason for the name is that the type species – that is the 1 animal that was selected as typical of the species and which represents the ‘gold standard’ for that species – now resides in the National Museum of Wales in Cardiff, UK. Thus this Chinese sea spider species was in fact ‘taken away’ to a noted museum for that group of animal (which is standard practice as well, so no accusations of kidnapping or robbery please!).
According to a recent FT.com article the company responsible for most of the destruction of coral reefs and reef habitat in the disputed Spratly Islands is listed on the Hong Kong stock exchange and is planning an overseas listing.
China Communications Construction Company (HK:1800), a large state-owned infrastructure group, announced in March that it was integrating its three dredging assets into a new company, CCCC Dredging, which it would eventually list overseas. That entity was set up in Shanghai’s Free Trade Zone on Wednesday.
China’s dredging programme has created about half a dozen islands in the South China Sea with deepwater harbours and at least one airstrip.
In the past 18 months, according to the US defence secretary, at least 2,000 acres of land have been reclaimed — more than has been done in 60 years by other claimants to the territory, including Vietnam, Malaysia and the Philippines.
Satellite images analysed by IHS Jane’s, the defence consultancy, show that Tianjin Dredging Company, one of CCCC Dredging’s three subsidiaries, operates most of the giant barges that have been digging sand from the seabed and piling it on remote coral atolls with names such as Mischief Reef, Suba Reef and Fiery Cross.
The flotation plans are curious for secretive Tianjin. A listing would require greater transparency and focus more attention on its activities.
In March CCCC said in a filing to the Hong Kong Stock Exchange, where it has been listed since 2006, that it “intends to seek listing of CCCC Dredging overseas at an appropriate market timing”.
Hongkongers and potential overseas investors should be aware that CCCC is not an ethical investment.
It is not just China destroying reefs in the South China Sea by reclaiming land to form island outposts to boost territorial claims. Vietnam is also reclaiming land by dumping enormous amounts of sand on two reefs destroying coral communities and changing the local ecology and likely adversely affecting fish stocks.
The photographs, shared with Reuters by Washington’s Center for Strategic and International Studies (CSIS), show an expansion of the land area of Vietnamese-controlled Sand Cay and West London Reef in the Spratly archipelego and the addition of buildings.
The director of CSIS’s Asia Maritime Transparency Initiative (http://amti.csis.org/), said the work included military installations and appeared to have started before China began a flurry of reclamation projects last year. “On one site, it has constructed a significant new area that was formerly under water and at another it has used land reclamation to add acreage to an existing island,” Rapp-Hooper said.
The images showed that Vietnam had reclaimed about 65,000 square meters (699,654 square feet) of land at West London Reef and 21,000 square meters (226,042 square feet) at Sand Cay. This compared to 900,000 square meters (9.6 million square feet) reclaimed by China at a single reef, Fiery Cross.
Satellite images show that since about March 2014, China had conducted reclamation work at seven sites in the Spratlys and was constructing a military-sized air strip on one artificial island and possibly a second on another.
It appears that claimants to the South China Sea have entered into a land building race that destroys ecology and depletes fish stocks as a result. There can be no real winners in such a race – everybody will lose.