Friday, June 17, 2011

not so undiscovered

The isolated water bodies of marine lakes are, like island systems, extremely vulnerable to threats from human activities. Particularly the highly isolated lakes could be irreversibly damaged. Some of the lakes near villages or the ‘resorts’ (camp accommodations north of Panah Panah for pearl farm workers) contained floating devices with cages. These were used to temporarily store recently caught fish. The introduction of fish or any other non-native marine species can radically change the diversity within the lakes. Introduced species can become invasive and dominant which could ultimately cause endemic lake species to go extinct. This actually also applies to us, so we always rinse all our gear in the evenings to make certain we do not unintentially bring in propagules of alien species.

Within Misool the most extreme form of exploitation was in a lake on the island Karwop. The whole lake had been transformed into an aquaculture containing fish such as tilapia. The density of fish was so high that the turbid water was literally bubbling with fish. The limestone rocks surrounding all lakes in Misool are porous and allow exchange of water with the adjacent waters. This means that the water from the aquaculture containing high nutrient concentrations and possible bacteria is a likely seeping to the surroundings, possibly causing harm to the coral reefs. It is a rather destructive practice that is also used in lakes of Vietnam; we sincerely hope it does not become common practice in Misool.

No comments:

Post a Comment