The snailfishes, family Liparidae (Scorpaeniformes), have found notable success in the hadal zone from ~6,000 – 8,200 m. These are the dominant fish group in at least five trenches worldwide. The hadal fish community is distinct from the surrounding abyss where solitary, scavenging fishes such as rattails (Macrouridae), cutthroat eels (Synaphobranchidae), eelpouts (Zoarcidae), and cusk eels (Ophidiidae) are most common.
Little is known about the biology of these deepest-living fishes, nor the factors that drive their success at hadal depths. Using recent collections from the Mariana Trench, Kermadec Trench, and neighboring abyssal plains, my research investigates the role of trophic ecology, pressure adaptation, and life history in structuring fish communities at the abyssal-hadal boundary.
In 2014, our international team of researchers discovered two new species of hadal snailfishes in the Mariana Trench. We described this new species using morphological and genetic data and gave it an official scientific name, Pseuodoliparis swirei Gerringer & Linley 2017. Check out the full taxonomic description of the Mariana snailfish here.
Stomach content and amino acid isotope analyses suggest that suction-feeding predatory fishes like hadal liparids may find an advantage to descending into the trench – where amphipods are abundant. More generalist feeders and scavengers relying on carrion, such as macrourids, might not benefit from this nutritional advantage at hadal depths. Read more here.
Hadal fishes have developed many adaptations to cope with high hydrostatic pressure. Some metabolic enzymes in hadal snailfishes from the Kermadec and Mariana trenches are adapted to function best at in situ pressures. This has implications for studies of trends of metabolic capacity with depth. Some enzymes may require additional stabilization to function under high pressure, such as with the osmolyte TMAO. Read more here.
Gelatinous Tissues in Deep-Sea Fishes
Deep-sea fishes have many adaptations to life in their deep-dark world. Some deep-sea fishes are gooey, having a gelatinous layer of tissue below the skin or around the spine. In a study published at Royal Society Open Science, we investigated the function of these gelatinous tissues. Why be made of goo? Read the full paper here. This one involves a robot snailfish!
Otoliths, small calcium carbonate bones in the inner ear of fishes, can give us insight into the life and times of an individual fish. As the fish grows, new opaque rings are deposited in these bones. When we cut the bone, we can see rings like the rings of a tree, allowing us to estimate the age of the fish. Otoliths also retain