Vaughn Fonlyewauee of Bog Walk High winning heat 7 of the boys' Class Two 150m in 17.8 at the Excelsior High School Development meet at the School on Saturday. Fonlyewauee was ninth overall in the time-final event won by Mario Haughton of Edith Dalton High in 17.1 seconds. - Ian Allen Photo

There are several activities, primarily human activities, which are responsible for the destruction of the coral reef. I have already discussed nutrient pollution, sedimentation, over-exploitation by fishermen and disease. Other damaging activities are inappropriate fishing methods, chemical spills, and global warming resulting in increasing hurricanes and coral bleaching. Today's lesson will discuss these.

1. Fishing Methods. Damaging fishing methods are a threat to coral reefs. These methods are varied and many. Here are some:

(a) Dragnet fishing - There are two types, namely, the use of beach seine where the net is dragged by hand, and trawl netting where the net is carried by two boats on either ends of the nets. In both cases, the net is dragged along the bottom of the sea. This scrapes off everything along the sea floor, overturns corals and uproots sea grass.

(b) The use of dynamite. The explosion not only kills the fish but destroys the reefs as well.

(c) Spear fishing - where the Spear goes into the reef and damages it.

(d) Many divers using tanks or hooka(h) use a sledge hammer and chisel to physically break open the reefs to obtain fish and lobsters hidden inside them.

(e) The use of certain chemicals to irritate the fish and lobster so that they are easily caught. These chemicals in turn kill the reef.

(f) Anchors badly placed or placed on the reef itself will destroy the reef.

(g) Fish pots set on top of the reefs will rub against the reefs with the swell, killing the coral animals. Fish pots when placed on sand between the reefs are easily moved against the reef by storm currents.

2. Chemical Spills. Many types of spill can cause problems for the reefs. Examples are:

(a) Oil spills. Oil is not poisonous but when it coats the reef it will prevent them from breathing. Unfortunately, the occurrence of oil spills is fairly frequent, occurring about five times a year.

(b) Caustic soda spills. These can occur at the bauxite ports. The problem created by this is that it changes the acidity/alkalinity of the sea, and will attack the coral tissue directly. The occurrence of this is less frequent than oil spills, and has happened in recent times.

3. Unsustainable Recreational use of reefs. The activities of snorkellers, divers and boats, may have a negative impact on the reefs. The divers/snorkellers may bounce the reef, damaging the corals, and, if sand is kicked up, corals may become covered and stressed due to suffocation. The collection of coral souvenirs may eventually lead to the destruction of the natural habitat of the coral. Improperly anchored dive boats may cause physical damage to reefs.

4. Global warming. In his text The Contemporary Caribbean, Robert B. Potter informs us that 'Small rises in sea temperatures caused by global warming have resulted in episodes of coral bleaching. Tiny algal plants live inside the coral polyp tissue in a symbiotic relationship with the corals, and a rise in sea temperature of only 1 - 2 ºC is enough to expel them from their host into the ocean, causing the corals to lose their colour pigmentation. Bleaching has increased in frequency and intensity over the last two decades and although reefs can recover, mortality of corals has long-term negative impacts on reef biodiversity.' Since global warming has a human origin, coral bleaching is a human impact. The problem of coral bleaching is getting worse annually.

5. Hurricanes. These natural phenomena seriously damage coral reefs, but in the past the reefs have been able to recover. The additional human stresses already mentioned (nutrient pollution, sedimentation, over-fishing, chemical spills, unsustainable recreational use and coral bleaching) which are relatively recent in time, may have made it difficult for reefs to recover naturally. Global warming in recent years has increased the frequency and intensity of hurricanes. There is therefore a human cause to the additional stress caused by hurricanes.

Although the concept is not fully tested, it is felt that the coral reef is also threatened by an increase in the levels of carbon dioxide in the seawater. This slows down the growth of the coral, and may also make the seawater slightly more acidic.

In the next lesson, I will go on to another topic, that of Coastal Pollution. Please do some reading on it.

Study Tip: ' If you fail to prepare, prepare to fail.'