The Impact of Climate Variation on the Golden Jellyfish, Mastigias papua etpisoni, in Jellyfish Lake, Palau: a Twenty-Year Perspective

The marine environments of the western Pacific archipelago of Palau and its iconic Jellyfish Lake are sensitive to conditions associated with climate driven ENSO events; these conditions include changes in water temperature, rainfall levels, sea level, and dysoxic events. Since the strong El Niño of 1997/98, we have been monitoring changes in Jellyfish Lake water conditions and its Golden jellyfish, Mastigias papua etpisoni, population to understand how climate events affect this unique ecosystem. Our data indicate an inverse relationship between seawater temperature and the estimated size of the Golden jellyfish population. Strong El Niño’s have a more pronounced effect, with two occurrences (1997/1998 & 2015/2016) of a subsequent total population crash of the medusae, most likely related to extreme drought conditions, dysoxic events and eventual rising water temperature. For both events, the medusae returned following polyp strobilation of new jellies once conditions were favorable. Data from our long term monitoring indicates the resilience of Jellyfish Lake and its Golden jellyfish population as they respond and adapt to extreme climate driven events.