Post by Schmidt Ocean Institute

🌊Deep-sea fish facts: grenadier edition 🌊 The #DeepWonders science team encountered this curious grenadier from the genus Coryphaenoides at a depth of more than 1,900 m, which is 2.3 times as deep as the height of the world’s tallest building, the Burj Khalifa in Dubai. Most grenadiers, also known as rattails, are considerably smaller; this individual was nearly 1 meter long. According to Marine Biologist @Beatriz Naranjo Elizondo, they are benthopelagic, swimming just above the seafloor while foraging. Scientists suspect their long, slender bodies enable slow, energy-efficient swimming, and their elongated shape accommodates a longer lateral line — a sensory organ running along the sides of a fish from the gills to the tail — enhancing their ability to detect vibrations in the surrounding water. This appears to be one of several adaptations that have enabled them to thrive in the deep sea, she writes. Rattails have large eyes to detect the faint glow of bioluminescent prey, along with highly developed sensory structures on their heads that help them locate food just above the seafloor. Most species also possess a chin barbel, a sensory organ that helps them detect prey in complete darkness. Beatrice adds that many male grenadiers also possess specialized drumming muscles attached to their swim bladder that can produce low-frequency sounds used during courtship or communication. Grenadiers are among the most abundant fishes in the deep, and they play a vital ecological role. As both predators and prey, they transport energy and recycle nutrients between the water column and the seafloor, helping shape deep-sea food webs and influencing the structure and dynamics of deep-sea communities. The #DeepWonders expedition team, led by Dr. Diva Amon of SpeSeas, is exploring the waters surrounding Trinidad and Tobago and the adjacent high sea, which the Trinbagonian team anticipates will inform future ocean stewardship in the region and beyond. Credit: ROV SuBastian / Schmidt Ocean Institute

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