Sperm Whales in Hong Kong, the Tai Long Wan Stranding and the Cruise of the “Cachalot” from 1899

On July 21st 2003 at about 9am, a sperm whale (Physeter macrocephalus) stranded alive on Tai Wan Beach in Sai Kung. The thought of any large whale in Hong Kong waters always surprises, but one as special and unique as a sperm whale is even more surprising.

Sperm whales are the largest toothed whales and get their unusual name from an oily waxy tissue in their head called “spermaceti”. They live in deep water and can dive deeper and longer than any other cetaceans – up to 2000m deep. They generally live offshore in water over a thousand metres deep where they feed on large squid and octopus. They tend to live in stable and long-term social groups, and they can live for up to 60-70 years.

Hong Kong waters are generally shallow and less than 40 m deep and not suitable for sperm whales. The sperm whale which stranded alive at Tai Long Wan Beach marked the first officially recorded sighting in Hong Kong. Previously the last recorded sighting in the wider Guangdong Coast was back in the 1950s.
With the help of Google and Project Gutenberg I have found much earlier record before 1899, though it is somewhat vague as to the exact location. In a book called ‘The Cruise Of The “CACHALOT”, Round The World After Sperm Whales’ by Frank T. Bullen, F.R.G.S., First Mate, published in 1899, the following mention occurs: “But, to the surprise of all, when we had arrived off the beautiful island of Hong Kong, to which we approached closely, we “raised” a grand sperm whale.”(Chapter 13). “Raised” here means caught and killed. It is not an official record, but I think the first mate of a whaling ship will have known how to recognize his primary target…

So sperm whales are no strangers to the offshore waters near Hong Kong and it shouldn’t surprise us too much that they may stray into shallow water. It is likely that the stranded animal at Tai Long Wan was sick, separated from its main pod, or drifted off course by the currents of two tropical depressions in the area at that time.

Chances of a rescue were slim from the outset as the whale probably already suffered from internal bleeding with its massive weight – no longer buoyed by water – exerting crushing pressure on the internal organs. Even if it had been successfully pulled out to sea again, it would not have been able to find food in the Hong Kong waters and would have been far from the deep water it normally lives in. A re-stranding would have been very likely. Sperm whales have hardly ever been rescued from beaches and released back to the ocean successfully.
The decision was made for a government veterinarian to euthanize the animal to prevent further unnecessary suffering.

A year after this stranding on the 24th January 2004, a sperm whale stranded on the coast of southern Taiwan, making headlines because the carcass famously exploded from the build up of decomposition gases while lying on a trailer on route through a small town (you can simply google: “exploding whale” for dozens of sites and archived news reports…). Five years later, on the 15th of January 2008 another sperm whale stranded on coast of Fujian (China Daily article with images) at a beach near Songxia Port in Changle. This was followed by a bigger stranding this year (2012) in Jiangsu Province where 4 sperm whales were stranded on March 16th. Let us all hope that this is not the start of a trend along the China coast.

All below images are courtesy of the Hong Kong Dolphin Conservation Society (HKDCS). If you enjoyed this article and the images, please consider a small donation to the HKDCS to support their excellent work. Oh – and please rate my blog and leave a comment. Thanks!

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…

Whale Shark at Sham Wan update

A whale shark Rhincodon typus was spotted at Sham Wan on Lamma Island on 27th of June 2012

The whale shark, Rhincodon typus, is a slow, filter feeding shark that is the largest living fish species in the world. It feeds on small shrimps, fish and plankton. The shark is found in tropical and warm oceans and lives in the open sea. The species poses no danger to humans.

This video clip was made by a member of the public and posted on Youtube. I take no responsibility or credit for the content of this clip. You can see that the shark is struggling in the rocky shallow water just off the beach (ca. 5 to 10 meters by my estimate). Eventually it makes its way back to sea. Reports suggested that it may have been spotted again off Deep Water Bay on the 3rd of July, but could not be confirmed. Whale sharks are found in tropical waters world-wide, so its presence in Hong Kong is not surprising. In fact, on the 6th of June 2008 at about 2pm a trawler caught a 5m whale shark and after identification by the Agriculture and Fisheries Department in at the pier off the Aberdeen Wholesale Fish Market it was released back at to the waters of Round Island around 4.30pm (see AFCD press release linked here). Tragically it died and ended up in a landfill (WWF HK statement).

Given how much sharks fin is traded and eaten in Hong Kong its more surprising that the shark got away without being caught, mutilated and sold for sharks-fin soup. What is really interesting is that this beach is not just a turtle breeding spot with AFCD protection and a beautiful scenic spot thanks to the regular clean-ups done as part of the turtle protection, but it also has some nice hard coral areas in some places and now a whale shark! I think it should be declared a Marine Park. Who is with me?

More Cases of Necrotising Fasciitis from Vibrio vulnificus infection

Vibrio vulnificus
Obtained from the CDC Public Health Image Library: CDC/James Gathany (PHIL #7815)

Further to the last post about Vibrio vulnificus – a free living marine bacteria found in warm waters, the Department of Health has made three press releases over the last 7 days of further cases of necrotizing fasciitis (flesh-eating disease) caused by Vibrio vulnificus infections in Hong Kong. V. vulnificus causes infection by ingestion (seafood) or through open wounds when swimming or wading in infected waters or via puncture wounds from the spines of fish such as tilapia. It prefers warm seawater or brackish (mixed fresh- and seawater) and occurs worldwide in warm salt-bearing waters and can be present in infected shellfish. In people with compromised immune systems, V. vulnificus is more likely to spread into the blood stream, when it can cause severe symptoms including blistering skin lesions, septic shock, and even death .

All three cases reported by the Department of Health in August had underlying illnesses (this could be e.g. hepatitis, HIV, diabetes etc.) and all had a wound on an arm or leg which when swabbed tested positive for Vibrio vulnificus: 

9th of August 2012: a 56-year-old man from  Yuen Long with underlying illness developed pain over left ankle on August 5. After admission to North District Hospital on the same day, he was diagnosed as having necrotising fasciitis (flesh-eating disease). An amputation was performed, but the patient’s condition deteriorated and he passed away on the next day.

13th of August 2012: a 77-year-old man from Kwun Tong with underlying illness presented right forearm redness, pain and swelling on August 8, recalling a puncture injury to his right forearm by a sharp object, suspected to be a prawn. He was admitted to United Christian Hospital the next day where medical staff diagnosed necrotizing fasciitis. The man received intensive care and his condition is all stable.

15th August: an 80-year-old man from Kwun Tong with underlying illness presented fever and chills on August 11 and developed redness on his left lower leg the next day. He was admitted to United Christian Hospital and was diagnosed with necrotising fasciitis followed by an above-knee amputation of the left leg. The man is now in serious condition.

I know of one further case where a man developed swelling and redness in one leg which had an open wound and which came into contact with seawater. The patient fully recovered after a week-long hospitalization and treatment with antibiotics.

According to a spokesman for the  Centre Health Protection (CHP), necrotising fasciitis is a serious bacterial infection which can destroy tissue and cause death within 12 to 24 hours after infection. The CHP reminds people to adopt the following preventive measures:

* Avoid foot/leg contact with dirty water when visiting a 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.

Patients should seek medical advice promptly if they develop symptoms and signs of infection such as increasing redness, pain and swelling.

 

Red Tide Sighting at Mirs Bay and Tung Ping Chau Marine Park

AFCD Press Release

Red tide sighted
Friday, August 10, 2012A red tide was sighted in Hong Kong waters over the past week, an inter-departmental red tide working group reported today (August 10).

Staff of the Agriculture, Fisheries and Conservation Department (AFCD) sighted the red tide at Mirs Bay and Tung Ping Chau Marine Park on August 6. The red tide dissipated yesterday (August 9). No associated death of fish has been reported by mariculturists so far.

“The red tide was formed by Scrippsiella trochoidea, which is common in Hong Kong waters and non-toxic,” a spokesman for the working group said.

The AFCD urged mariculturists at Sha Tau Kok, Ap Chau, Kat O, O Pui Tong, Sai Lau Kong, Tap Mun, Kau Lau Wan and Sham Wan to monitor the situation closely.

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

Ends

For the original article click here.

Golden-Thread, See-Through Fins and a lot of Nasty Little Bones – It’s Fish No.3

Scientific Name: Nemipterus virgatus
Common Names: Golden-Thread, Golden Threadfin Bream, Hung SamNemipterus virgatus - do not eat!
Origin: China
Date: 7th Aug 2012
Where: Fusion in Discovery Bay
Weight: 0.294 catty (178 g)
Cost: $22.90 (78$ per catty)
Recipe: Steamed with some herbs
WWF Sustainable Seafood Guide: Think Twice

Named Golden-Thread – I presume – because of the golden thread-like line down its sides. This is a smaller fish and according to WWF not so sensitive to fishing pressure because they are fast growing and reach maturity at 15 months, but still overfished. Quite honestly I do not know why, because I am certainly not going to bother with this fish again, but more on that later. Although fishing of Golden-Thread is by small-hooked long lines which does not produce a lot of by-catch the management measure in place in Hong Kong are apparently weak. So the stocks have been declining in the South China Sea, with catches being mostly young fish.

Herklots & Lin – my 1962 guide to this project – actually just give the genus Nemipterus sp. for this fish in their book, so I figured N. virgatus is as good as any Nemipterus, right? You probably don’t care either….anyway…

The Golden-Thread by Herklots & Lin (1962)

Wikipedia tells me that it occurs “in the Western Pacific, from Southern Japan to Northwest Australia and the Arafura Sea. It is one of the most popular commercial and food fish in the East China Sea and northern South China Sea.” Once again I have no idea why its popular. Maybe because it can be made into fish balls?

Computer Generated Map for Nemipterus virgatus (un-reviewed). http://www.aquamaps.org, version of Aug. 2010. Web. Accessed 8 Aug. 2012.

It has a maximum length of 35 cm….mone were about 15 cm (I had to buy 2, as one couldn’t have fed a mouse), which is roughly the length at first maturity, too. So it seems WWF are right: basically this fish is being caught as soon as it hits maturity, probably even a bit before, which is very bad for conserving the fish stock. If you eat them before they reproduce, guess what? There won’t be any left soon.

Its non-migratory and spends its time between 18-33 m depth but can go down to 220m. Its a demersal fish (lives new the seabed) and inhabits muddy or sandy bottoms and feeds on crustaceans, fish and cephalopods (squid, cuttlefish and octopus).

So much for the science…here is the culinary part: what a rubbish fish! Take my advice, if you don’t want to spend 1 hour picking through the tiny bones and bits of what is size-wise a large goldfish, don’t bother with this fish. Fish balls are the only way to make this palatable: puree the sucker(s) in a blender to chop the bones into pulp and you have something resembling a meal…but thats not my idea of eating a fish…

I give it a score of 1/10. And that one point is just because the actual taste of the flesh which was just average. Everything else about it was a pain in the neck (literally…I smaller one bone that scratched all the way down my throat for about 5 minutes).

I never even asked the wife….she just said it’s too small and makes the whole house stink of fish….which is true this is one of the fishiest fish I have ever tried! Here is a picture of the worlds most pathetic fish meal.

a pittyful plate of Nemipterus virgatus - steamed

Hong Kong Underwater Photo & Video Competition 2012

Hong Kong Underwater Photo & Video Competition 2012 Poster

For more information click here to get to the AFCD website’s article.