17. Jun, 2017

The sinking of the heavy cruiser  USS Indianapolis, at the tail end of World War II, was the worst at-sea disaster in U.S. naval history, surpassed only by Pearl Harbour.  The ship went on a secret solo mission from San Francisco to Tinian, a small island in the Pacific. The objective was to deliver two key components for the atomic bomb that would ultimately fall on Hiroshima.  Its secret mission over, the cruiser departed Guam and steamed for Leyte, an island in the Philippines, for training. Shorthly after midnight on  28 July 1945 the Indianapolis was hit by two torpedo’s  from the Japanese submarine I-52, and sank in just 12 minutes.   

The sinking. Of the 1200 saylors 800 went into the water but only 316 survived the nearly five-day ordeal. The survivors were not spotted until August 2  1945.   The US Navy had received alarm signals, but assumed that  they came from  the Japanese to lure their enemy.  The ship had no escort and no sonar for detecting the submarines. Part of the tragedy is that the Navy did not know of the sinking for a few days, when finally an anti-sub patrol airplane spotted an oil spill and survivors bobbing in the water. Every year end July the now remaining 31 survivors  used to get together for a reunion in Indianapolis to commemorate the event, remember the dead, and celebrate the lives they were lucky not to loose.

The Indianapolis is, albeit indirectly, connected with a significant event in my personal life. The ship delivered two key components for the atomic bomb that would ultimately fall on Hiroshima and  destroy almost  the entire populations of two Japanse cities. The bomb  put an end to the war in South East Asia, and  lead to the liberation of thousands of Dutch civilians emprisoned in Japanese camps in the Dutch Indies since 1942. This also included me, a little boy of 6 years, and my  mother,  staying in the women camp Banjubiru in middle Java. I can still remember that night end August 1945. The Red Cross packages were finally distributed, and in the darkness I spotted the red glowing cigarette ends of the women happily chatting and  celebrating the end of the war. That was only  one month after the sinking of the ship that contributed to our liberation.

The sharks  Another reason why the sinking of the Indianapolis continues to fascinate people, is the sharks story. It was re-ignited and spread over the World  by the blockbuster Jaws, when shark hunter Quint recounts of bobbing in Pacific waters for days while sharks circled him and his fellow sailors, waiting to see who would be the next victim. Quint described the sharks 'black, lifeless eyes, the blood-curdling screams, the ocean turning red’. His account probably chilled more people than the demonized great white shark itself. His, or rather Spielbergs description  of the eye could have been inspired by Cousteau, who also spoke of the Oceanics eyes as 'hard and cruel looking'. The story seems to be globally  correct since it follows  the vivid witnesses from survivors of the Indianapolis, but  it likely also exaggerated the number of victims that were  actually killed by sharks.

The sharks that were held responsible for the ‘massacre’ were probably Oceanic white tip sharks. Oceanics scavenge  and search the great empty oceans where it may often taken a month for them to find a decent prey. Along the Hawaii coast they often accompany groups of pilot whales for a still unknown reason. They are also known to follow ships and will get into action when they hear or sense a shipwreck. For that reason they were also called 'sea dogs' by sailors. Unfortunately for survivors of shipwrecks, hungry whitetips looking for food will take a bite out of sailors and passengers who land in the water. The initial target of sharks were probably  not the living victims of the Indianapolis,  but the hundreds of dead bodies floating in the ocean around the groups of survivors that wisely huddled together. It is also unlikely that the sharks consumed  their victims,  but rather bit parts of the body and  legs leading to the death of those that still lived by  blood loss.

The number of men that were actually killed by the sharks has been difficult to estimate,  but it probably amounted only a small  fraction of the 800 men, of which the greater part succumbed to burns, dehydration, exhaustion, and drowning. Some say  that around 150, others that  50 men were killed by the sharks. Most of the crew were able to get life jackets, but many of the vests became waterlogged or would tend to slide down the body, increasing fatigue. Some sailors grabbed on to floating nets, or the extremely fortunate got into a life raft.

Man as bait or bait provider Sharks generally don’t eat human flesh but may bump and occasionally bite a human by accident, or to check out its smell or taste. Scuba divers and UW photographers can even dive safely with the Oceanics during supervised baited shark trips in the Bahamas or supervised unbaited trips in the Red Sea. Despite their bold and dominant behavior, there have sofar been no reports of sharks attacking or biting  scuba divers  on these occasions. But as said, drifting helpless in the open ocean without diving gear could be a life treathening situation when the Oceanics are around you. In the Oceanics instinctive brain there must be a line that separates a helpless human castaway from a scubadiver during a baited dive: the first is  potential bait the second  bait provider.

It is also dubious that sharks are attracted by the smell of human blood.  Its rather the blood spread by  a struggling fish, like a harpooned whale in the open ocean, that will trigger a frenzy of sharks. The shark attacks of the Indianapolis are also reminiscent of those of December 2010 when several tourists were seriously bitten by sharks (probably  also Oceanics) along  the beaches  of Sharm el Sheikh in Egypt. Although it still remains a mystery what triggered this rare event, a plausible  theory that emerged  is that the the dumping of sheep carcasses in the Red Sea by a livestock transport during the Islamic festival of Eid al-Adha had attracted the sharks to the shore.








 Jeremy Stafford-Deitsch. Shark. A photographer's story.Headline Book  Publishing 1987.

13. Jun, 2017

The dangers that threaten our natural environment is a recurrent theme in these blogs. Not so much because it is a pleasant subject to write about, but simply because it is something  that has to be repeated over and over again. Until society and its political and economical leaders realize that its destroyal could also imply the end of the human species. The natural environment concerns  miriads of species still living in the wild forests and  oceans. Which people  who care about nature and the under water world will not accept to be destroyed. But what can be done?

The Coral Triangle: an area  suffering most  from blast and cyanide fishing.

Expansion of responsible diving tourism and the establishment of Marine Protected Areas can help in creating an economical counterforce that concurrently will protect and conserve a wealth of marine life, including the splendid coral reefs. And it would also offer new employments for the local populations. But this can only succeed if local and national authorities accept to play a leading role in establishing and guarding these areas. 

Climate  change Many people feel troubled by the change of our climate, and its effects on the environment. The cause is believed to be massive fossile burning, leading to global warming of the earth. The Paris Agreement could be an important step to mitigate global warming. But its alarming manifestations, such as melting glaciers, permafrost and ocean ice are not something that can be restored in a couple of years or decades.  Global warming probably started already with the onset of the industrial revolution, some 200 years ago.  One reason why its effects are now so alarming, could be that global warming is not a linear (1,2,3,..,) but exponential (1,2,4,8,..) proces. Then there  are  the climate  ‘sceptics’. They may accept climate change but deny that the cause is environmental. They might even consider the environmentalists as   agitators from the left that are out to destroy capitalism. In an ironical way,  I hope that the sceptics are right, because when climate change is natural not environmental, there is nothing more we can do than lean back in our chair and accept the caprices  of mother nature.

Direct human interventions Climate change  however  should not be our only concern. The current damage of the natural environment is for the largest part caused by direct human interventions. The list seems to be without end. Oil platforms, massive oil spills, cutting down rain and mangrove forests, the ivory trade, finning of sharks, and last but not least massive pollution of the air as well as the oceans*. Tons of plastics drifting in the sea have now even reached  the most remote pristine areas in the world.  Even  the climate sceptics may  go along with this, although they will argue that industrial pollution is simply the price modern world has to pay for  for greater prosperity and a healthy economy.  Helping to protect parts of the environment that we cherish and want to preserve for future generations is something we can do on the short term. Its damage often results from blind search for profit. Or from bad management and illegal activities, such as the trade in wildlife were  criminal organizations cooperate with authorities and corrupt members of the policy forces.The same holds for destruction of the marine environment, of which some examples are given below.  

Destructive fisheries Destructive, often illegal  fishing  practices  are  currently  the most acute danger for  the marine environment. Many fishing boats still carry on with these practices, despite the fact that national legislations have identified and banned many of them. This list also seems to be without end. One  is  overfishing which means that  more fish are caught than the population can replace through natural reproduction. Its is driven by what is called Tragedy of the commons  each of many fishers is self-interested and benefits financially from a large common pool of fishes. The fishers assume that the resource pool is so large that each of their large-quantity harvest is seen to be of little harm to the resource pool. Hence they behave in ways that advance their own interest by fishing as much and fast as they could each time they fish. But catching too many fish harms the balance between marine species and will reduce  fish stocks to below acceptable levels for populations that depend mainly on fish for their proteins. Bycatch often occurs  when ship use driftnets or gillnets that catches non-target species like sharks, turtles or dolphins.  Another is bottom trawling, a nasty industrial method  used by  big  boats in the high seas. Enormous nets weighed down with heavy ballast are dragged along the sea floor, raking up or crushing everything in their way, from fish to ancient coral.  Then there is ghost fishing, which are  nets made of long lasting synthetic material that are accidentally or intentionally left in the sea. These nets continue to trap fish and even  large marine mammals, which die of exhaustion or suffocation and struggling to get to the surface to breathe. Most of these methods result from poor fishery management leading eventually to financial losses through depleted stocks. 

Blast fishing occurs primarily in Southeast Asia, the western Pacific, and eastern Africa. The Coral Triangle  (see insert)  is the area that suffers most from this aggressive fishing method. For example, a study conducted in 2002 reported that fishing with explosives had caused the degradation of about 70% of Philippine coral reefs and reduced annual fisheries production by about 177,500 metric tons in the 1990s. This biological wonderland – which spans Indonesia, Malaysia, Papua New Guinea, the Philippines, Solomon Islands and Timor-Leste –  not only contain numerous splendid coral reefs, but also  thousands of  islands rich in mountain forests and woodlands.  Blast fishing is often used  by local fishermen in smaller boats that find the techniques to be easier and more productive than traditional methods. Home made bombs consisting of a mix of  kerosine and fertilizers  are most popular.  After the bomb explodes, the fish killed or stunned by the shock wave from the explosion are collected. Underwater shock waves produced by the explosion stun the fish and cause a desolate gray moonscape. Even coral gardens that were among Asia's most spectacular dive sites like Mabul and  Komodo National Parkhave have been  the victim of bomb blasting. 

Poison or cyanide fishing is another method often used in the South East Asia triangle. In many places the use of poison to catch fish is a traditional technique, but negative effects have multiplied since plant-based substances were replaced by chemical poisons. Sodium cyanide tablets are dissolved  in a bottle to form a toxic liquid  that is squirted on the fishes in the vicinity of a coral reef. The mixture stuns the fish without killing it, making it easy to catch in a net, or even by hand.It started in 1960 in the  Philippines to supply the international aquarium trade. But since the early 1980s, a much bigger business has emerged: supplying live reef fish like coral groupers for the restaurants of Hong Kong, Singapore, and, increasingly, mainland China. Cyanide kills  organisms in the ecosystem, including the corals forming the reef. It has devastated many reefs of the Philippines  and eastern Indonesia – where an estimated 65 tons of cyanide are poured into the sea each year.

Counter measures. Luckily some counter measures were also taken to protect the area.  In 2012, the director of the Philippine Bureau of Fisheries and Aquatic Resources declared an “all-out war” against dynamite fishing and other illegal fishing practices. In 2014 the Reef Defenders began an aggressive program to create a network of Background Blast Monitoring (BBM) equipment throughout South-East Asia. BBM equipment has also been installed at Mabul Island in Sabah, Malaysia. Another initiative was the  decision made in 2014 by the government of the Raja Ampat islands in North Western New Guinea to ban the harvesting and trade of sharks and manta rays from its marine waters. 













27. May, 2017

Killing rare animals that live in the wild has become a lucrative trade that cleverly responds to primitive instincts as well as ancient traditions. It could  imply selling permits to rich Americans for hunting lions, elephants or rhino's on an African safari, or killing endangered species and trading their organs to Asian countries. A key role here is played by Traditional Chinese Medicine (TCM). TCM is based on the belief in the curing power of acupuncture and herbs, as well as dried organs of rare animals.

Left: Upper panel: Dried  totoaba swim bladders for sale at Asian market. Lower panel: the Vaquita, a small porpoise often killed as bycatch in the gillnets

But to date, unbiased scientific studies* have not been able to confirm its medical claims. For example, rhino horn contains mainly keratine, meaning that eating your finger nails would probably be equally effective. Unfortunately, a dangerous spin-of this old cultural tradition is the growing illegal smuggle on the black markets that still make huge profits in Asian countries.

Threathened species Examples of products used for medical or culinary purposes are powdered rhinoceros horn, shark fins and  the pangolin. The disastrous effects of shark finning on the shark population have been extensively described in various media. The pangolin is a small, scaly, insect-eating mammal been plucked from the wild across Asia and Africa for consumption almost exclusively in China, where their scales are used to treat everything from rheumatoid arthritis to inflammation.  But the  list of products contains  much more examples  of dubious cures based on body parts from endangered wild animals. A bizarre  example  is  Mong La, in northernmost Burma (officially now called Myanmar)  where tiger penis is served as a special expensive dish on the menu. Tiger penis is also avalaible in Guolizhuang – Beijing’ Famous Penis Restaurant that serves cooked yak penis or sheep gonads. Tiger penis has to be ordered months in advance. Some conservationists  fostered the hope that Viagra would reduce the poaching of  animals  of which  body parts are  used as aphrodisiacs. Alas,  not  so in Asian countries.

One of the reasons of the booming wildlife trade is China’s growing industry with its rapid expansion of a middle class. This  raised  hundreds of millions  of Chinese from poverty up into the middle class, giving them now access to exclusive culinary or ‘healing’ medical products. But it also stimulated a new highly profitable but less riskful illegal market for former drug traffickers.

Marine species: the totoaba and vaquita. An  example of a marine species  that is on the verge of  extinction due to Chinese  trade is the totoaba (Totoaba macdonaldi). It is the largest member of the family Sciaenidae that is endemic  in the upper Gulf of California.  The fish is caught by pirate Mexican fishermen with their gillnets. The totoaba, a highly endangered species, is caught for its swim bladders which are smuggled to China for sale on the black market.  Here the swim bladders are sold  at an average price of $20,000 per kilogram (see picture upper panel). The dried bladders  were previously used by wealthy Chinese that used such bladders or “fish maws,” to make soups thought to smooth the discomfort of pregnancy and cure joint pain.  Signs of the totoaba slaughter  began showing up in the upper Gulf of California around 2011.  A circular drumlike device that is set to the side of the motorized vessels draws in the nylon nets much faster, thereby revolutionizing the size of the catch and the fishing industry.

The totaoaba however, wasn’t the only victim of the Chinese bladder boom.  So was the vaquita (Phocoena sinus), a rare species of porpoise about 1.5 m long and endemic to the northern part of the Gulf of California. The word vaquita is Spanish for "little cow". It is distinguishable by the dark rings surrounding their eyes (see picture lower panel), patches on their lips, and a line that extends from their dorsal fins to their mouths. Their backs are a dark grey that fades to white undersides. According to recent IUCN report  only  less than 300 are left in the northern Gulf of California today. Although it is not a target for fisherman, its population decrease is largely attributed to bycatch from the  nylon gillnet fishery used for shrimps as well as the (illegal) totoaba for the Chinese trade. These gillnets  are particularly treacherous because their mesh is about the same size as a vaquita’s head and are  hardly visible underwater. This type of fishing is now counteracted  by  the  Mexican government, that launched a two-year ban on the use of gillnet fishing in the area.  

Sources  and links

*Unbiased in this context means: with no national or cultural interest favoring studies with a positive outcome. This excludes a.o. the Journal of Chinese Medicine, but not the bona fide  Chinese Journal of Medicine.







15. May, 2017

The recent fatal shark accident in SW Australia where 17 year old surfer  Laetitia Brouwer died after a bite in the leg by a Great White Shark has ignited the culling debate in Australia. Hard liners in the debate have blamed the government to  listen to much to the ‘insane shark conservation policies that have cost another life', and insist on measures to bring down the number of  great whites sharks at the beaches.

Left:  A sonar buoy emitting signals in a shark protected environment*

But what measures should be taken by the  government to effectively protect swimmers and surfers along such an extended coastline comprising south west, south as well as south east Australia?  The primary cause  of the increased fatalities of the  last decade seems to be the increasing numbers of  beach visitors, not of the great white sharks. The favorite beaches of surfers and swimmers are spread over a large stretch of coastline in Australia, many of which  are unsupervised. Unfortunately, there still is no effective warning system signaling  the areas where  a visit of great whites could  be a potential hazard in the holidays season or  -even better-  on a certain  day or  week-end.

A direct invasive intervention  measure  that has proven sofar to be relatively effective is shark culling via shark nets and drumlines  with baited hooks  that are anchored to the  sea floor.  Larger sharks that are caught are killed, smaller ones released. In  both Queensland and New South Wales  culling  is  permitted in cases where sharks are deemed to present a serious threat to public safety.  Opponents  however have  expressed  concerns about  the impact  of culling on on both targeted and non-targeted threatened sharks species,  and as ‘bycatch’ of species like dugongs, dolphins, turtles and other fish.   Many sharks  caught since 2001 were not great whites,  or were caught in areas where no fatalities have ever occurred. In addition, culling  may only be effective for  more territorial shark species. But great whites are not territorial,  except in areas that lie  in the vicinity of their favorite hunting grounds such as islands harbouring colonies of seals or sea lions. Although they show some fidelity to sites meant for pupping and mating, much of their time seems to be spent with following long migratory routes in the open seas. Human surfers and swimmers on a beach  may occasionally attract their attention when they are patrolling the coastline, but are not on their menu.

Only  a minority of  the population in Australia including New South Wales seems to  support culling of sharks, and among Australians there is a rising trend toward greater balance between wildlife, marine life and national values. It still remains a curious fact that a fatal accident caused by a wild animal elicits much  more emotion and publicity than a fatal traffic  accident. Apparently  the hazards of  our modern industrial  society are accepted more easily by mankind  than an occasional  attack of  a great white  mistaking a human for a  prey entering its territory.

Alternative  non invasive  measures  labelled as Shark Mitigation  that are now in development include  technologies such as sattelite and acoustic signaling  of the presence of sharks in  certain risk areas. For online measures of shark movements battery operated SPOT (Smart Position and Temperature Transmitting)  tags are attached to the sharks dorsal fin. These tags transmit a signal  or ‘ping’’ to a satellite array whenever  the dorsal fin breaks the surface of the water. The New South Wales Government has even developed  software like the Shark Smart app to provide beachgoers with real-time data of sharks' movements. Shark tagging  and related shark tracking devices have proven to be  higly useful tools to study migratory patterns of individual sharks. Some  amazing results have recently been obtained by researchers  working with great whites at Isla Gualape in Mexico (See: http://www.marinecsi.org/). But to make it work as a accident prevention tool will require tagging  of numerous great whites, which may not be feasible considering  the enormous size of their habitat.  

Online shark tracking could work however as a supplementary  tool to  use in  combination with other techniques. An interesting and perhaps more feasible   option  are strings of sonar buoys that are stationed in potential danger areas like beaches often  visited by swimmers or surfers. These solar-powered surface buoys provide power as well as communication functionalities. A buoy or chain of buoys will constantly emit sonar signals. When the sonar detects a large fish entering  the guarded area, it will tranmit the signal to a satellite receiver which in turn relays it to a beach station  (see insert).

On the longer term shark mitigating technology  aims to develop a  shark monitoring  network that  relies on several parallel  sources of  information,  including not only  data  derived from tagged shark detection  but also from local sonar buoys, air  patrols and sight detection by beach guards. This information  would  finally become assembled and  digitally mapped on a shark activity map.  Visitors could inspect  the map with their Sharksmart  app to check  any recent activity before using the beach or going out to surf. 









21. Apr, 2017

In the great oceans of the world plastic debris accumulates in five great circular currents called gyri. These Five gyri are driven mostly  by Westerly winds and influenced by  the Coriolis  effect  causing  a bend  of 20-45° to the right, on the northern hemisphere.  On the southern hemisphere the gyre moves counter clockwise.

Pacific and Atlantic garbage patches. Two notorious gyri lie the Pacific: the North Pacific Gyre and South Pacific Gyre. The North Pacific Gyre became known as the ‘Great Garbage Patch’, because of its accumulation of large quantities of plastic. Most is runoff from highly populated coastal cities, and from maritime activities such as fishing and shipping. Its estimated to  consist of 100.000 billion  tons of garbage. Mostly larger pieces, but also smaller pieces. The smaller pieces pulverize under the influence  of salt water and photo degradation, and enter the food chain of marine mammals, fishes,  tortoises and the albatros. These high density particles  are difficult to spot with the naked eye and can sink  to lower layers of the oceans. The South Pacific gyre is now on its way to beat the Northern gyre, pollution wise: 18 tons of plastic recently reported on Henderson island a part of the Pitcairn group. This beats all records.  


Transportation of plastic debris (in green) accumulated in the North Atlantic garbage patch to polar regions. Polar ice cap in August 2013 is shown in white area.(Source:  Science Advances)


In the Alantic ocean we find two similar circular currents:  the Southern and Northern  Atlantic gyri.  Originally documented in 1972, the North Atlantic Gyre is another area of man-made floating marine debris. This patch is estimated to be hundreds of kilometres across in size,with a density of over 200,000 pieces of debris per square kilometer (see picture above). Which means that it contains plastic marine pollution in a pattern and amount similar to what has been found in the Great Pacific Garbage Patch.

A sixth garbage patch: the North pole Plastic accumulation at polar latitudes was sofar considered as  unlikely,  because of the lack of nearby pollution sources (I  am not considering the pollution caused  by oil rigs in the Nordic seas  here).   A different picture was  presented by  a recent study* that extensively sampled the Arctic Ocean for floating plastic debris. Although  human population north of 60° latitude is relatively low, and  plastic debris was scarce or absent in most of the Arctic waters, it reached high concentrations (hundreds of thousands of pieces per square kilometer) in the northernmost and easternmost areas of the Greenland and Barents seas. The fragmentation and typology of the plastic suggested an abundant presence of aged debris that originated from distant sources, most likely  Western Europe and  Eastern US.  

The source of the  plastic is the North Atlantic  garbage patch, which is transported northward by  a gulfstream known as   thermohaline circulation, also called ‘conveyor belt’ (see insert). The oceanic pathway was tracked back from the Arctic using satellite observations and floating buoys. This showed that the poleward branch of the thermohaline circulation transfers floating debris from the North Atlantic to the Greenland and Barents seas. Areas  which would be a dead end for the plastic conveyor belt.  When the warm water of the gulfstream reaches Nordic seas it sinks to lower layers of the water, while the plastic particles accumulate  in the colder surface layers in  the northern part of the Nordic areas. Areas that are already in the red zone due to global warming of the earth and massive melt down of glaciers in Greenland, and the sea ice at the North Pole.

What to do? Stopping with the  production of plastics altogether appears to be the  most radical solution. Another is to  stop using single use plastic: plastic bagsplastic bottlesplastic to-go containersplastic takeaway cups, and plastic straws. Which means: practically all articles sold in our Super Markets. Stop buying that stuff would perhaps  be a sensible thing to do. Unfortunately, in our modern society ''anything that interferes with one's personal feeling of comfort and well being is regarded as suspicious. What  feels nice is accepted blindly.  But any type of information -including expert reports- suggesting that we should change our life style or bring sacrifices, is often set aside as manipulation or hysteria''(1). Then there is of course  also the Prisoners Dilemma  explanation: 'why should I make sacrifices by changing my life style, if my fellow citizens (also reasonable people) do not have that same intention?  Why to be soft in a tough world?'  But, as far as plastic is concerned there are better alternatives, such as  mass production of biobased instead of oil based polymers, called PEF (or polyethylene furanoate) a next generation plastic.

A third solution is to clean up the mess in the oceans, which at first sight seems to be an impossible task, considering the extent of the infected areas in the immense oceans. A promise however lies in a clever and ambitious plan masterminded  by a young Dutch engineer Boyan Slat and  hydrodynamic specialists from  the Technical University of Delft. Their project aims to clean up the garbage patches.  Basic elements are long distance barrier segments floating in the sea, and a central platform collecting the garbage.**

But for the near future it looks like  the world  has to face  the reality of a plastic soup  that degrades life in the oceans, and possibly will further  accumulate  and  spread to seas that have so far been spared.

Sources and links

R. W. Obbard, S. Sadri, Y. Q. Wong, A. A. Khitun, I. Baker, R. C. Thompson, Global warmingreleases microplastic legacy frozen in Arctic Sea ice. Earth’s Future 2, 315–320 (2014)




(1) Here I quote Bas Heijne, in his weekly NRC column of April 22.