1. Overfishing: losing keystone species

Overfishing occurs when so many fish are caught from a reef, that the natural rate of reproduction is exceeded. This can be true for targeted fish species, but also for species that are caught accidentally and die as bycatch. This results in declining fish populations and disruption of the reef ecosystem.

For example, overfishing can lead to the depletion of key herbivores, such as parrotfish, which are essential for controlling algae growth on reefs. When these herbivores disappear, algae can overgrow and smother corals, harming the reef’s health.

Removing certain other species from the reef ecosystem can also have cascading effects. For example, the removal of predators like groupers, snappers and sharks can lead to an increase in fish that eat corals. The loss of specific species can disrupt the delicate balance of the reef, impairing its overall health and resilience.

2. The damage by destructive fishing

Certain fishing techniques, like blast fishing and cyanide fishing, can be highly destructive to coral reefs. Blast fishing involves using explosives to stun and kill fish, also causing extensive damage to the reef structure. Fishing with the toxin Cyanide not only harms the targeted fish, but also the surrounding corals. These practices harm both the reef’s inhabitants and the corals themselves.

Also more conventional fishing gear, like nets and traps, can physically damage coral reefs. When these materials get caught on the reef, the corals can break or be smothered, leading to their death. This habitat destruction not only harms the corals but also the fish and other animals that rely on the reef for shelter and breeding.

Striking a balance

Coral reefs are extremely important for local fishermen,but fishermen can undermine their own livelihoods by using harmful fishing methods. As more and more people depend on fishing, it becomes increasingly important that those fisheries are well managed. When managed sustainably, fishing can provide long-term income and food to many coastal people. A healthy reef would not only continue to support fisheries, but also all other benefits such as tourism opportunities and coastal protection.

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