It’s not often an abyssal predator is christened “cute,” but the ocean’s midnight zone has just done just that. This newly found creature, initially photographed in unparalleled beauty by advanced submersible imaging capability, is not merely stunning in its small, cuddly demeanor, but stunning in a set of adaptations which render it viable in one of our planet’s most extreme habitats.
The fish initially appeared in a remotely operated vehicle (ROV) survey, the round body and abnormally front-facing, large eyes combining to make it irresistibly cute-looking. But hiding behind the cuteness are a series of very specialized features for living thousands of meters beneath. Similar to most bathypelagic animals, it is lined with dark pigmentation to remain inconspicuous, and its mouth contains hard, curved teeth to make certain that whenever it engulfs prey, it’s caught forever. Biologists observed a characteristic bioluminescent organ on its chin, an ornament such as the fancy barbels of the dragonfishes, to entice prey into the bottomless void.
These were virtual impossibilities to observe without today’s technology for deep-sea exploration. New ROV-mounted cameras can now function at depths greater than 6,000 meters, facilitated by cutting-edge low-light sensors and stabilized 4K imaging optics to observe natural behaviors without disturbing animals. LED arrays made to reproduce the pale illumination of the deep enable scientists to see animals in normal behavior, detecting the subtle movement and interactions lost or scattered away by earlier lighting technologies.
The research was also helped by a new method in species determination. Instead of the old, decade-plus routine of specimen collection, preservation, and global comparison, scientists applied a “cybertype” approach. In minutes of encountering the fish, the researchers obtained high-definition 3D images, morphometric data, and archived tissue samples for genomic sequencing. As URI Professor Brennan Phillips put it, The current workflow is not appropriate. It’s a major reason why we have so many undescribed species in the ocean. Through robotics, imaging, and molecular biology being integrated, the researchers reduced the identification process from decades to days.
The bioluminescent organ of the fish provides an indicator of its function in the ecosystem. Far down in the ocean, where close to 90% of animals below 1,500 feet produce light, light production is a general function predation, communication, and camouflage. How bright and what wavelength the light is implies that it could be an attractant for tiny crustaceans and also for signaling to possible mates. All these specializations are because of convergent evolution, and bioluminescence arose independently in ocean animals at least 40 times.
Analyses of these characteristics in context are significant as well, since deep-sea creatures tend to lose their normal characteristics when taken out of water. The ROV’s highly sensitive bioluminescence detection equipment, employing cooled CCD cameras and extremely sensitive photomultiplier tubes, detected the organ’s soft pulses without disturbing them. Multi-spectral imaging also enabled researchers to analyze the emission’s spectral profile, giving insights into the fish’s likely prey and predators.
Its wider importance is in what it tells us about ocean science. Oceanographers believe that between 700,000 to 1 million species of organism live in the oceans, at least two-thirds of which are undescribed. They occupy extreme environments such as the bathypelagic zone, where elevated pressure, low temperature, and scant food stimulate extraordinary evolutionary creativity. Without today’s exploration ability autonomously operating underwater vehicles with artificially intelligent navigation, environmental origin DNA samplers, and long-duration sensor systems such species would go unknown to science.
With climate change, deep-sea mining, and pollution threat to these delicate environments, the capacity to record as quickly as possible biodiversity is more than an intellectual exercise. If you want to know what has been there before it’s gone, this is a new way to do that, Phillips said. The “adorable” deep-sea fish is thus not simply an oddity it is a warning of the necessity to explore, understand, and conserve the vast, dark realms of our planet before their inhabitants are extinguished in the dark forever.
