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Battling
the Curse of Marine Litter
International Coastal
Cleanup Singapore
The Curse of Marine Litter | Situation
in Singapore mangroves | What the data tells us
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Text
by N Sivasothi
Pictures by Victor Tan
Last
September, 400 students, teachers and volunteers struggled through soft
mud at low tide to reach various mangrove sites during the 10th International
Coastal Cleanup Singapore (ICCS). They found their pre-determined quadrats
and sectors with the help of guides, and started collecting and categorising
the marine trash in the mangroves of Kranji and Sungei Buloh. Trash bags
were weighed and stored at special points above the high water mark for
collection during the second phase of the operation ("wet ops') later that
day.
After about 90 minutes, they returned to discover that the stream
they had struggled through earlier had filled up again with the tide!
This was a carefully planned surprise to wash off the mud they had
been splattered all over with.
Guides in their bright orange-caps conducted the water crossing, shepherding
students and teachers through the high waters two at a time, keeping
a careful eye over each and every participant, and the precious data
sheets.
A week later, on September 15, more than 1,200 volunteers, mainly
students and their teachers and some organisations, tackled marine
debris on beaches all over Singapore. |
|
ICCS 2001: Low tide crossing
into Kranji mangrove
High-tide crossing to return to base
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Like
them, more than 750,000 people around the world in 77 countries and 54 states
of the USA took to the beaches, rocky shores and reefs in the same effort
to rid the sea of marine trash. Though impressive, this was a decline in
participation numbers due in part to the September 11th tragedy in the USA
that occurred just days earlier.
The Deadly Curse of Marine Litter
Why all the fuss? Besides being an eyesore, marine litter or debris can
suffocate marine organisms, both invertebrate (for example, crabs and worms)
and vertebrate (for example, fish, turtles, dugongs) animals and plants.
Post-mortems have revealed up to six square metres of plastic in an individual
mammal's stomach! Seals wear collars of plastic litter, marine turtles confuse
plastic bags for jellyfish and choke or starve to death, and in one study,
90% of albatross chicks on Midway Island in the Pacific Ocean had plastic
in their throats.
Fishing
nets can also be quite vicious - they trap all sorts of animals, and
over the years, I have come across crabs, especially horseshoe crabs,
snakes, birds and fish trapped in nets. All died slowly, either by
getting roasted in the sun during the low tide or by drowning during
high tide.
On several occasions since 1988, I encountered 20-50 invertebrates
(particularly the Forceps, Thunder and Mangrove Horseshoe crabs) all
trapped in a net at the surface of very soft mud, during low-tide
research trips.
These animals bear many jointed limbs, and become badly entangled
in nets. If time or tide is kind, I attend to them on the spot with
a knife (hence a reason for carrying a safety knife).
On one occasion, students helped me drag the net back to Sungei Buloh
Wetland Reserve, where the staff, equipped with scissors, helped to
unravel and cut away the fine fibres intricately woven among the many
joints of arthropods.
Park rangers tell me that they have also dragged nets out of mangroves.
These had been laid out by poachers or had floated in with the tide.
It is hard work, but it would be too cruel to leave behind.
In July this year, a group of us laboured away on the north bank of
Chek Jawa to release sting rays, Flower crabs and Giant horseshoe
crabs trapped in a discarded net before the tide rose too high.
One evening at Mandai Besar in the early 90's, a friend and I gingerly
approached a heron entangled in a net. Keeping well clear of the sharp
beak that it reared in preparation to stab me with, I threw my T-shirt
over the head of the frightened bird to calm it down. Quickly, we
sawed through the nets with the rusty parang we were carrying. Soon
it was scrambling off, saved from an inevitable drowning, if not for
the opportune crossing of our paths that day. |
|
Fish
net entanglement at
Pulau Seringat
Flower
crab
entangled in net
Releasing horseshoe
crabs from nets
Getting
rid of nets |
Plastic - the blessing and curse of modern history
Most of the material in marine debris are plastics, metal and glass, which
do not break down quickly, and this trash can pile up for decades and will
not be cleared but for concerted human effort.
Such is the
case in our mangroves. Nestled away in strand lines, often beyond the view
of the casual visitor, is a trash line that has accumulated over decades.
Hence the word trash line rather than strand line.
| The
trash load is so high, it prevents the re-growth of plants and colonisation
by animals. Here you can find almost all the components of an average
household - bottles, pots, toilets, refrigerator, washing machine,
oven, sofa, hats, shoes, clothes, steering wheels, tractor tyres,
and yes, even the kitchen sink! You are in greater danger of being
cut by a sharp piece of glass in our mangroves, than by being bitten
by a crocodile. |
|
Building
a living room from
marine trash in the mangroves |
Examine any spot on the trash line, and you will see plastic, plastic and
more plastic. Plastic has been both a blessing and a curse of the 20th century.
In recent times, there has been an explosive amount of plastic debris entering
seas and oceans. Recent research (Barnes, 2002) suggests that animals such
as bryozoans, hydroids, polychaetes and barnacles hitch a ride on the flotilla
of debris, a veritable shipping system for marine fauna - and this has more
than doubled recently. These animals become more widely distributed than
they would otherwise, and add to that very great threat of invasive alien
species, and now even to remote shores rarely accessed by man's shipping
traffic such as the poles of the earth.
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