Scientists still studying cause of Palawan jellyfish bloom

Published March 29, 2020, 12:00 AM

by manilabulletin_admin

By Ellalyn de Vera-Ruiz 

Jellyfish experts are seeking more answers to explain the sudden appearance of blooms of jellyfish in the waters of Palawan.


Photos and videos of the jellyfish surfaced on social media last March 11 and March 23, respectively.

In a video taken by Alimar Amor last March 23, an abundance of jellyfish can be seen in the waters of Corong Corong Beach in El Nido, Palawan.

Meanwhile, Dinel Aurello shared a photo captured earlier on March 11 showing “stranded” jellyfish along the coast of Sitio Ducul, Brgy. Buenavista in Coron, Palawan.

Sheldon Rey Boco, co-founder and chief investigator of the Philippine Jellyfish Stings Project, said the species in the video and photo are likely the same, which he initially identified as Crambione cf. mastigophora, commonly called “tomato” jellyfish and locally known as “labong-labong.”

It is a “true jellyfish” under a group of common species called Class Scyphozoa, he noted.

So-called outbreaks 

“These months probably have enough nutrients, abundance of jellyfish food and higher temperature that have ‘accelerated’ the production of ephyrae and or growth of medusae (its most conspicuous life stage),” Boco explained.

“These hundreds or thousands of medusae are probably present in late January or February but because of wind, current and tidal conditions, they only seem to appear during March in Palawan. The atmosphere (wind intensity and direction), water velocity, current, tide and even geological features of the bay or any body of water can influence the occurrence of medusae and their blooms.”

Boco pointed out that there is not enough data to make conclusions as to how and why jellyfish blooms occur.

“One thing is certain – that jellyfish numbers and occurrence of blooms follow a pattern of ‘natural oscillations,'” Boco said.

He said scientists are still trying to find out the cause of oscillations of numbers of jellyfish through time.

“There are years when blooms or populations of a jellyfish are high and there are also years when they are few or even almost absent.

“We, jellyfish scientists, also don’t know if climate change, ocean acidification, nutrient enrichment can affect jellyfish populations and the frequency and size of jellyfish blooms.”

He emphasized the need to conduct more tests and research to be able to make conclusions about the phenomenon and correct “misconception” that climate change is causing the blooms.

Benefits and disadvantages

The jellyfish, aside from having ecological benefits, are edible and fisheries-important, Boco said.

In many Southeast Asian countries, he said, some people “dry the jellyfish to be sold or exported to other countries like Japan and China, with jellyfish as food in their cuisines.”

However, Boco said that these blooms can be a nuisance for tourists who want to enjoy swimming or for people relying on fishing as source of livelihood “since large numbers can clog fishing nets or prevent them from spear-fishing, for example, due to the harmful stings, although they are not lethal compared to the stings of many cubozoans (box jellyfish).”