Jellyfish Lake, Eil Malk Island, Palau, Pacific Ocean

A significant reduction in the Jellyfish Lake medusa population had also been noted in 1987. This was previously attributed to turbulence generated by scuba diving that caused disturbance of the toxic layer. However, given that it occurred within the time frame when an unusually high sea surface temperature had been detected, it might reasonably be surmised to have been caused by a rise in water temperature that was the most likely cause of the 1998 die-off.
• Moon jellyfish
The moon jellyfish exhibited unusual damage in the 1998 time frame; however, the population seemed no smaller than usual.