Summary
Highlights
To understand the oarfish's presence at the buoy and its specific scent attraction, David enlisted deep-sea cameraman Roberto Rinaldi, using rebreathers for quiet, prolonged dives. They switched to another meteorological buoy ('Côte d'Azur') known for attracting more fish and started collecting mucus samples for genetic analysis, which revealed two potential species of oarfish.
The oarfish, often referred to as the "sea serpent" or "king of the herrings," is the longest bony fish in the world, known mostly through beached corpses. Its striking appearance, rarity, and size fueled ancient superstitions, portraying it as a fearsome sea monster.
Despite its historical notoriety, little was known about the oarfish's biology until recently. Off the coast of France, scientific equipment accidentally allowed high-tech divers to observe and study living oarfish, revealing their extraordinary habits.
In 2000, the Oceanographic Observatory of Villefranche-sur-Mer deployed 'La Boussole,' an oceanographic buoy, 40 miles off the coast of Nice. Anchored at depths exceeding 8000 feet, this buoy studying water color and plankton became an accidental gathering point for various ocean animals, including a great white shark.
During routine maintenance dives, scientific diver David Duke encountered an oarfish near the buoy. He observed its vertical swimming posture, contrasting with historical depictions. The encounter was brief, as the oarfish was sensitive to bubbles and retreated to deeper waters.
In Japan, the oarfish is known as 'ryugu no tsukai' (messenger of the palace of the gods), with beachings sometimes linked to earthquake myths. Dr. Tyson Roberts, a world expert, used MRI and X-ray technology on beached specimens to study its anatomy. Discoveries included its tiny brain and the unique position of its nostrils inside its mouth, allowing it to navigate by smell in the dark depths.
Observations of beached oarfish often show mutilated bodies. Dr. Tyson Roberts proposed 'serial autotomy,' where oarfish repeatedly self-amputate parts of their tail, similar to lizards. This is believed to be an energy conservation strategy, allowing the fish to focus resources on vital organs and reproduction. Fossil evidence from Italy supported this ancient behavior.
To understand their diet, researchers used special traps at different depths. Krill, a small shrimp, was found in abundance and its lipid signature matched that found in oarfish tissue. Krill's nocturnal vertical migrations to feed on plankton, and their bioluminescence, attract predators like the oarfish.
David and Roberto undertook dangerous night dives to observe oarfish feeding. They discovered that oarfish possess bioluminescent organs on their head, acting as lures to attract prey in the dark depths. These organs also serve as a signaling mechanism. The oarfish’s stunning beauty and unexpected behavior during these encounters posed a risk to the divers, as the fish would sometimes rapidly descend, pulling the divers with it.
The scientific efforts of David and Roberto unveiled the first secrets of the oarfish, transforming it from a mythical sea monster into a fascinating, albeit eerie and harmless, creature of the deep. Its unique adaptations, such as olfactory navigation, autotomy, and bioluminescence, highlight the mysteries still hidden in the ocean's depths.