Why do jellyfish bloom in huge numbers?

Jellyfish blooms are mass increases in population that can happen when ocean conditions favor them. Many blooms are linked to warmer water, nutrient changes, and reduced competition or predation after overfishing removes species that normally eat jellyfish or their competitors. Some jellyfish can also reproduce quickly, either sexually or asexually, which helps populations expand fast. Blooms can affect fisheries, tourism, and power plants if large numbers clog intake systems. Although jellyfish are ancient animals, their sudden outbreaks are often tied to modern changes in marine ecosystems.