A
resplendent isle with much to boast about, Sri Lanka is fast losing its most
valuable resources to neglect and irresponsibility. While most of us are too
busy berating the authorities, we conveniently forget our individual roles in
the protection of our environment.
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| Death by dynamite |
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| Coral rubble |
The
mere existence of mankind has had an impact on global marine environments. The
oceans are seen as ‘bottomless’ sources of food and natural resources,
convenient repositories for trash and poisonous waste, or something to be
dredged, filled, or drained when deemed necessary. Although we know better in
these environmentally-aware times, misuse continues at home and all around the
world, while areas with improving attitudes and practices will remain scarred
for years to come.
The Sri Lankan context
Sri
Lanka has a total land area of 65,000 km2 and maritime rights to an
area of 230,000 km2. Its 1,585 km coastline comprises of 300km of
beaches and sand dunes. Fisheries are the major economic use of the maritime
area, and the fishery sector contributes nearly 3 percent to the GDP and is an
important source of employment and foreign exchange to the country. Of this,
coastal fisheries constitute about 72 percent of the total marine fish catch
and support nearly 90 percent of employment in the fishery sector while fish
provides 65 percent of the protein in the Sri Lankan diet. 100 percent of Sri
Lanka’s population lives within 100km of the coast and are directly or
indirectly dependent on it.
The threats
The
threats faced by the marine environment are both anthropogenic and natural.
Some of the primary threats include climate change, fragmentation and habitat
loss, overexploitation and pollution.
Natural threats:
Natural
threats include coral bleaching, storms and predation. The environmental
imbalance caused by human activities has exacerbated climate change effects
that have increased the frequency with which coral bleaching episodes and
storms occur. However because of the intangible nature of our impact, humans
are quick to shirk off responsibility. Moreover, the tangible destruction
caused by humans has meant that when natural events such as tsunamis occur, the
damage caused is far more prolific.
Coral
bleaching which is caused by unusually high sea surface temperatures is the
process by which corals lose their colouration either due to stress-induced
expulsion of symbiotic unicellular algae or due to the loss of pigmentation
within the algae. The massive 1998 global bleaching event had an impact on many
of our reefs including those within Hikkaduwa National Park and Bar Reef Marine
Sanctuary. Recovery of the former has been much slower than at the Bar Reef
because of the added anthropogenic pressure resulting from unregulated
visitation.
Anthropogenic threats:
Dynamite
fishing is a prime cause of reef damage and mass fish kills, most of which go
to waste due to non-collection. Dynamite is also used in the ‘laila’ net
fisheries which involve the surrounding of large shoals of fish with nets that
hang vertically in the water column and in recent times has led to the demise
of pods of Spinner dolphins that associate with the target fish species. Other
destructive fishing methods include the use of synthetic vs. cotton nets. Because
these nets are visually and acoustically undetectable, by-catch of charismatic
species such as dolphins and turtles are frequent. In addition to being
undetectable, the fibers are strong and nearly unbreakable thereby preventing
animals from escaping once caught. Nets that are lost at sea continue to kill
marine life for hundreds of years because of the durability of the synthetic fiber
– a process known as ‘ghost fishing’.
The
dugong, a large-bodied herbivorous marine mammal, which was once common along
the north western coastal waters of Sri Lanka, was taken at a rate of 100-150
individuals per year in the 1950s. They are now rarely seen due to a continued
harvest and as a result of the destruction of their primary food source – sea
grasses. The illegal harpooning of dolphins around the coast of the country has
also led to a decreased inclination to ‘bow ride’. ‘Bow riding’ is the
behaviour of dolphins in which they frequently swim or ‘ride’ the crests of
ocean waves. As dolphins are frequently used as ‘back up’ species (an
attraction in the absence of the target whale species) by the whale watching
industry, this reluctance towards a natural behavior may prove disadvantageous.
Coral
mining for lime spelt the demise of many of Sri Lanka’s southern reefs. In
place of the once live and flourishing corals that provided habitats for fish
and numerous other marine organisms lie vast tracts of coral shards and empty
spaces. The future for these areas is bleak and the protection of the reefs which
once provided the coastline against the high energy waves, is now lost. A
direct result of this destruction was the unfortunate loss of lives in Peraliya
on the south west coast during the 2004 tsunami.
Harvesting of fish without consideration of sustainable
yields has shifted the future of our protein source into the hands of aqua-culturists.
Although aquaculture is not without its own problems, it will form the only
alternative as more fish stocks begin to collapse. Collection of reef fish and
seahorses, also known as ‘cut flower’ species because of their short life span,
for the ornamental fish trade also occurs freely around our coastlines and such
activities may cause an imbalance in the reef ecosystem. The prolific and
unsustainable collection of chank and sea
cucumber over the years has lead to the sequential demise of inshore stocks and
led to the exploitation of the deeper off shore stocks.
Upstream activities also have an impact on the marine
environment. Deforestation inland is one such example. Although the marine and
inland terrestrial systems seem so disparate,
they are not. The denuding of forests in the upstream catchment areas causes
erosion and unusually large amounts of soil to
enter the rivers and eventually exit through the lagoon mouths into the sea.
Corals being living organisms, are suffocated by the sediment that settles on
them and die. Coral destruction causes the loss of habitat for fish and also
sources of food.
Garbage and pollutants absent mindedly or purposely
tossed into the oceans have many detrimental effects on marine life.
Contaminants such as heavy metals and PCBs used in upstream areas also enter
the sea via rivers and lagoons and result in a change in water quality. Wastes
such as acids, radioactive materials, matter used for biological and chemical
warfare and other highly toxic substances are also regularly dumped directly
into the ocean despite the introduction of the Ocean Dumping Act in 1972 that renders
such actions illegal. Despite
being dumped into ‘isolated’ oceans their sheer interconnectedness and global
circulation patterns ensure that the wastes end up on everyone’s doorstep and
are incorporated into the food webs. As coral reefs are biological assemblages
adapted to waters with low nutrient content, the addition of nutrients in this
manner favors species such as algae that disrupt the balance of the reef
communities. Pollution such as plastics and polythene are documented to cause
the death of many organisms. Many species of marine turtles that feed on
jellyfish are known to mistakenly consume polythene bags which block the mouth
and throat and inhibit breathing and feeding. Furthermore, if they are ingested
they inhibit digestion due to the extended stomach sending confusing signals to
the brain causing the turtle to stop eating and ultimately die of starvation.
Entanglement in marine debris also inhibits surface breathing of turtles and
marine mammals, foraging, predator escape and
mating behavior.
All
these threats acting individually or in combination result in severe impacts on
the biological production of the world’s oceans and the services they provide
to billions of people today. With the acceleration of climate change, the
impacts on marine life from other stressors will become severely exacerbated
and the ability of ecosystems to recover will be impaired. We now live in a
world that has to contend not only with so called natural threats, but those
posed on the system by our everyday actions. It is imperative that when we live
by the philosophy of ‘leave only footprints, take only memories’. Is it not up
to us to make the right decisions in an attempt to save our marine life for
future generations?
Do you know how long it takes for the following
items to degrade?
Glass
bottle – 1 million years
Fishing line – 600 years
Plastic bottle – 450 years
Aluminium can – 80-200
years
Plastic cup – 50 years
Plastic bag – 10-20 years
Cigarette filter – 1-5
years
Newspaper – 6 weeks
Now sit back and reflect on the
impact they have over their lifespan. Dispose responsibly.
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