Durban — While taking a stroll along the uShaka Beach shoreline at lunchtime on Thursday, the South African Association for Marine Biological Research (Saambr) staff stumbled on bluebottles and velellas along the shoreline.
The bluebottle is also known as Portuguese-man-of-war while the velella is known by the much gentler name of by-the-wind sailor.
Saambr said that in KwaZulu-Natal, it is more common to come across bluebottles than the smaller, lesser-known velella.
As a result, Saambr decided to explore the differences and similarities between bluebottles and velellas.
“They both belong to the group of animals known as Cnidaria which includes jellyfish,” Saambr said.
Exploring their colonies, Saambr said a bluebottle is not a single animal but a colony of individual modified organisms each doing a different job attached to a soft gas-filled float while velella is also made up of a colony of tiny individual animals but, instead of a gas-filled float, they sport a delicate air-filled raft.
“A bluebottle regularly dips its soft float into the ocean to prevent it from drying out while the velella are unable to manipulate their upright triangular sails,” Saambr said.
“Bluebottles possess long threads with coiled stinging cells inside them which they use to catch prey such as small fish and zooplankton. Their stings can be extremely painful to humans.”
Saambr continued: “The velella, on the other hand, relies on a central feeding gastrozoid beneath the raft which is surrounded by a fringe of short stinging tentacles. In most cases, their stinging cells are not harmful to humans.”
A similarity the two share is that they have no means of locomotion other than their “sails” which render them at the mercy of the prevailing winds to move around.
“It is probable that both these animals were brought ashore by the recent strong onshore winds,” Saambr said about their presence on the shoreline.
A hint Saambr shared was that next time you are strolling along the shoreline and see bluebottles perhaps look a little closer and you might see a velella.
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