The Red Banded Lobster (Justitia longimana previously known as Justitia longimanus), also known as the Long-Handed Spiny Lobster, is widely distributed and occurs in all tropical and subtropical water of the world, but rarely encountered by recreational scuba divers due to its obscure habitat: very deep waters where ambient or sunlight is virtually absent, typically below 60m/200ft and extending far beyond 275m/900ft, or concealed deep within submerged caves and caverns shielded from any form of light.
This lobster which grows a maximum length of 15cm/6inch or so, is believed to feed on small reef invertebrates or scavenge on larger animal carrion.
When illuminated by our underwater video lights, the lobster’s body appears vividly orange-red with white and red banding on its antennae. However, without illumination, these colours appear dark grey to black, providing excellent camouflage for life in the more concealed parts of our oceans. The lobster’s large and darkly pigmented eyes are also well adapted for life in a dark environment, and similar to all lobster relatives, their long antennae provide important sensory information about their surroundings.
The Red Banded Lobster displays sexual dimorphism: the males’ first legs or “chelipeds” possess a pair of claws with a downward-closing tip, somewhat resembling a snap-carabiner, while females lack this claw-like appendage, having a simple pointed leg tip instead. The true function of this unusually shaped atypical claw is not yet clear to scientists. Due to their deep and dark habitat, studying these lobsters proves to be exceptionally challenging for marine scientists.
Being illuminated by large, bright submersible video lights is an experience the small lobster, which is light-shy and prefers the obscurity of the cave where it was filmed, would never have encountered in its tranquil and shadowy habitat. The abrupt intrusion of brilliance likely sent shivers through its delicate sensory receptors, prompting it to retreat further into the crevices of the cave, seeking solace in the familiar darkness it had known since its early days. The unfamiliar radiance cast eerie and elongated shadows on the rocky walls, distorting the recognisable shapes into surreal forms that seemed to dance with an otherworldly energy. In simple terms, the lobsters in this underwater environment must have been shocked by my sudden brightly illuminated appearance in their obscure submerged habitat.
To minimise the lobster’s stress in such situations, it is advisable to employ red lights prior to filming. Red light is invisible to sea creatures, allowing the underwater videographer or photographer to position themselves, set up their equipment, and frame the subject accurately without unduly distressing the animal. Once all preparations are complete, the video lights can be turned on to commence filming the creature. By doing so, the subject's stress is reduced, leading to a more natural depiction and insight into the animal’s natural behaviour. Underwater photographers can also use red light in the form of a focus light, enabling them to achieve precise focus and framing for a photo. They can then counteract the red lighting with a burst of flash from the underwater camera’s strobes.
For more information on the other denizen that inhabit this cave please go to vlog posts 67 or click this link https://www.beyondscuba.com/post/ghost-boxer-shrimp-stenopus-pyrsonotus
and vlog post 45 https://www.beyondscuba.com/post/the-variable-thorny-oyster
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