Why are jellyfish blooms increasing around the world?
Jellyfish have survived five mass extinctions, and now their populations are exploding as oceans change.
The answer
Jellyfish blooms appear to be increasing in many ocean regions, driven by a combination of overfishing their predators and competitors, rising ocean temperatures, nutrient pollution, and habitat modification. Some species like the Nomura's jellyfish in Japanese waters can grow to 2 meters in diameter and form blooms of millions of individuals, clogging fishing nets and power plant water intakes. Jellyfish thrive in degraded marine environments because they tolerate low-oxygen conditions better than most fish. Having existed for over 500 million years, they are among the oldest multi-organ animals, and some scientists worry that parts of the ocean could shift from fish-dominated to jellyfish-dominated ecosystems.
Source: Proceedings of the National Academy of Sciences
- jellyfish
- blooms
- overfishing
- ocean ecology
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