Blue button (Porpita porpita) spotted in Cochin estuary!

A fascinating group of blue buttons !

Have you ever seen these charming, fancy bluish critters? For sure, these wonderful animals will wake your curiosity for a while. Here we spotted some of them in Cochin estuary, Kerala, India.

Porpita porpita, commonly called as ‘blue buttons’, are smaller jelly buttons - the marine animals passively floating on the surface waters with the help of wind and waves. These free-floating animals are sometimes seen in thousands of colonies, whenever there is a bloom, and are often wrongly identified as jellyfishes. However, they are not true jellyfishes, instead belonging to the scientific class Hydrozoa, in which each individual species is composed of a hydroid made up of individual zooids and each function differently. Some perform stinging and defense, others are for predation, while only one group will be busy with reproduction. Therefore, they are not one creature but a group of animals collectively forming the entire animal!!

Central air filled disc allows them only to float not to swim deeper

Bluish tentacles surrounding their golden-coloured and gas-filled float have stinging cells (Nematocysts) along the margins. One of the popular closely related individual is Portuguese man o' War (Physalia physalis), which can deliver a venomous sting so powerful that it can kill fish, and even injure humans. Nevertheless, blue button stings are not powerful enough to harm humans; rather, they can cause skin irritation or a small rash. However, this is enough for these     carnivorous species to get their larval prey.

Not enough proof to blame that oil tanker behind!

They are supposed to be found in the surface waters of an Open Ocean and their presence in the low saline estuarine waters is suspicious. There could be a few reasons behind it. One possible reason is a ballast water discharge from the oil tankers to the estuarine waters, and the other reason might be the strong monsoon tides which brought these floating beauties along the margins of the estuary to show up in front of us. In essence, their survival in the low saline water is dubious!

Knobs of stinging cells are visible on the tentacle margins

Photo Credits©️: Ajin Madhavan