Coral reefs are among the most biodiverse and valuable ecosystems on Earth, but they face severe threats from overfishing and unsustainable fishing practices. Here we highlight the main impacts of these harmful practices on coral reefs.
Fish that have made this place their residence
Fishing methods & bycatch
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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hot, acidified and turbulent oceans
Coral reefs are incredible underwater worlds that teem with life, but they are facing a serious threat from the changing climate. We will explain the three major ways how climate change is affecting these delicate ecosystems.
1. Warming oceans and coral bleaching
As our planet warms due to the accumulation of greenhouse gasses in the atmosphere, the oceans absorb much of this excess heat. This rise in ocean temperatures directly impacts coral reefs. When water becomes too warm, corals expel the tiny symbiotic algae (zooxanthellae) living in their tissues. These algae give corals their vibrant colors and provide essential nutrients through photosynthesis. Without them, corals lose their primary food source and appear white, a phenomenon known as coral bleaching. Bleached corals are more susceptible to stress, diseases, and death. They can recover when water temperatures decrease again, but this appears increasingly unlikely in a warming world.
2. Ocean acidification and dissolving homes
As we release more carbon dioxide into the air, the oceans absorb a lot of it. This makes the water more acidic. Corals and other marine life that build shells and skeletons from calcium carbonate will struggle to do so in more acidic water. This means their homes are at risk of dissolving, making it difficult for them to survive. Ocean acidification is a slow process, and therefore the impacts have only recently become visible. However as ocean acidification becomes more severe, it also becomes much more difficult to stop.
3. Extreme weather and storm damage
Warmer ocean temperatures can intensify tropical storms and hurricanes. These extreme weather events pose a direct threat to coral reefs. Powerful waves can break and dislodge corals, leaving them vulnerable to diseases. The debris from these storms can also smother the reefs, suffocating them and hindering their recovery.
Urgent climate action needed
In conclusion, climate change is having large and negative impacts on coral reefs. Additional, less understood threats such as rising sea levels and altering ocean currents can further harm reefs. The longer emissions continue, the worse these impacts become. For that same reason, any effort to reduce emissions will help to make a difference. By understanding these challenges and taking steps to reduce our carbon footprint, we can help ensure the survival of these and other vital ecosystems.
Together, we can work towards a healthier planet and a brighter future for coral reefs and all the life they support.