Beautiful Creatures of the Night ...
In this blog series we will be giving scuba divers, the layman marine gazers, and even non-divers a little insight to the creatures we encounter underwater.
Let's introduce the Giant Basket Star - perhaps missed by the day-time diver in its curled up sleepy state, however illustrating its majestic beauty at night as it comes out for a twilight supper ...
Animal, fish, plant? What is it ...
The Giant Basket Star can be found in abundance in the Tropical Atlantic and Caribbean Sea.
The Gorgonocephalic, or better known as the Giant Basket Star, can be seen in its full glory practically everywhere on a night dive in the Caribbean seas of Martinique. The ones photographed here were taken in Anse Dufour.
Found from between 6 m and 30 m, during the day it nests in the crevices of reefs, giant sponges or barrels, or can be found attached, folded into a tight ball, to alcyonaria, gorgonians or corals. At night it glues itself to the top of a support and unfolds into its full fan-like beauty. Larger individuals, too heavy to be supported by alcyonaria, unravel on the top of hard corals and rocks.
The tight ball begins to unfold as night falls
A central disc gives way to 5 arms, each dividing into four branches, two of which are not as branched as the others, allowing the animal to cling to a support and move, and two long, much more branched, thin at their ends allowing the animal to feed.
Colours range from dark brown to yellow brown, to cream and as you can see in the photos really add to the dramatic ambiance of a night-dive!
The central disc can measure up to 8 cm, and its arms can span up to 1 m which is in stark contrast to what you see during the day when it remains curled into a tight ball protecting itself from predators. As night falls this fascinating sea-creature fans out to form its unmistakable basket-like shape, hence its given name, and faces into the oncoming current like a parabola.
The Basket Star is a suspensivore - a suspension feeder. Just after dusk, the moment plankton ascends to the surface, the basket star attaches itself to the nearest support and comes out to feed. The thin branches, armed with many small hooks, create an efficient trap. The food is passed down to the disc part of the body where the mouth can be found and supper is devoured. The basket as well as feasting on plankton is also capable of preying on other small organisms and even manages to entrap small fish!
Basket stars reproduce via a behaviour known as broadcast spawning, which is where females release eggs and males release sperm into the water column at the same time. This method increases the likelihood that eggs will become fertilised and that they will not be eaten by seafloor predators.