What are the primary threats to coral reefs?

The primary threats to coral reefs include overfishing, climate change, pollution, and destructive fishing practices, which collectively impact the health and resilience of reef ecosystems. Overfishing can lead to an imbalance in the marine ecosystem, as key species that help maintain coral health are removed. Climate change is particularly significant, contributing to rising sea temperatures that can cause coral bleaching and increase the frequency and intensity of coral diseases. Pollution, including nutrient runoff from agriculture and urban areas, can lead to algal blooms that smother corals and compete for space and resources. Destructive fishing practices, such as the use of dynamite or cyanide, directly damage coral structures and can decimate local fish populations essential for maintaining healthy reefs.

In comparison, while the other options highlight issues that can affect marine environments, they don't encompass the main threats faced specifically by coral reefs. For instance, invasive species and oil spills can also harm marine ecosystems but are not as universally recognized as the primary threats to coral reefs as those listed in the first option.