Page 43 - Coral Reef Teachers Guide

Coral Reef Teacher’s Guide Benefits, Threats, and Solutions

and more fisheries are collapsing
(species of fish are disappearing
from many areas) due to damag-
ing fishing techniques and over-
fishing (more fish being harvested
than the area can reproduce).
In many places, traditional fishing
methods have been replaced with
super-efficient modern technolo-
gies, often with damaging long-
term effects. The introduction
of motorized boats and SCUBA
gear, such as masks and fins,
has increased the catch, often
to unsustainable levels. Biode-
grad- able traps and nets woven
from vegetable fiber or coconut
fronds have been replaced with
non-bio- degradable nylon, metal
and wire.
Figure 3-5. Massive coral broken in half by boat anchor. (Photo: Jim Thomp-
son)
When lost they often become dangerous: en- wild stocks. Giant clams, fish, conch, seaweed and
tangling and injuring or killing marine life shrimp are among the many farmed species.
(Figure 3-4), break- ing corals, or continuing Unfortunately, while mariculture provides a
to catch fish that will never be collected. means of employment and reduces pres- sure
on overexploited stocks, it can have a negative
Cyanide poison is used by fishers in Indone- impact on the reef. In many areas, entire man-
sia, the Philippines, and other island nations grove forests have been bulldozed to make
to stun fish, making them easier to catch. shallow ponds for these farms, eliminating
Chlorine bleach and quinaldine are used in juvenile fish nurseries and habitat for marine
the United States. Hunting for food or aquar- birds and animals. In addition, these farms
ium fish, the fishers shoot the chemical solu- siphon already short fresh water supplies, poi-
tions at reef fish or into coral enclaves where son the water with chemicals and antibiotics,
they live. The poisonous residue kills coral, and cause a decrease in wild fish populations.
invertebrates, and other fish. Ultimately, the coastal people are left with lit-
Fishers in the Pacific and southeast Asia of- tle protein source since they are unable to af
ten blast reefs with dynamite or other ex- ford the mariculture product.
plosives that rupture fishes’ air bladders so • Damage from Boats
they can scoop them up as they float to the
surface. The explosions destroy reef forma- In areas that are popular with recreational,
tions, kill non-target fish (by-catch), and of- diving or fishing boats, the reef is subject to
ten kill or maim the fishers themselves. damage from acci- dents and carelessness.
Anchors tossed on coral break the fragile
Some fishers also use ‘Muro-Ami’, which is animals (Figure 3-5), and the chains drag a
the name of the net that fish are driven into swath of destruction around them. Boats and
when hundreds of boys pound on the cor- ships that run aground on the reef can de-
al and wave white plastic streamers. Again, stroy hundreds of corals in an instant. Pro-
this technique damages the coral and results pellers churn up sediments that smother the
in huge quantities of by-catch. reef. Boat bilges and toilets are discharged,
• Mariculture dumping an overload of algae-causing nutri-
ents into the water. Some cruise ships and recre-
Mariculture, the farming of marine plants ational boats have been documented dumping
and animals, is becoming more popular in their trash overboard, despite laws against
the tropics, often in response to the loss of ocean dumping.

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