A large deep-water fish that was previously identified in the Southeastern Pacific has recently been found around the Hawaiian Islands and off the coast of Central California, according to a team of marine biologists from the Monterey Bay Aquarium Research Institute (MBARI), the Pacific Shark Research Center and the California Academy of Sciences.
This pointy-nosed blue chimaera (Hydrolagus trolli) was videotaped by MBARI’s remotely operated vehicle Tiburon near Hawaii at a depth of 5,384 feet (1,641 m). Image credit: Amber N. Reichert et al, doi: 10.1186/s41200-016-0095-5.
The fish in question is called the pointy-nosed blue chimaera (Hydrolagus trolli).
Also known as the abyssal ghostshark, this species is a large deep-water ghostshark, probably up to 4 feet (1.2 m) in total length, usually found at depths ranging 2,000-6,500 feet (610-2,000 m).
“The pointy-nosed blue chimaera is a highly distinctive chimaera species, often identified by a combination of the following characteristics: an even blue-gray to pale blue color, a pointed snout, a dark margin around the orbit with dark shadows along edges of the lateral line, and preopercular canal and oral canals usually sharing a common branch,” the researchers said.
“It is a large, although slender bodied species with a narrow head that evenly tapers to a whip-like tail.”
“It is often caught with the giant black chimaera (Hydrolagus affinis), and the range of these two species may overlap in some areas, but the pointy-nosed blue chimaera is readily separated by its distinctive blue coloration and more acute snout.”
First named in 2002, the pointy-nosed blue chimaera is known to live in waters around Australia, New Zealand, and New Caledonia.
But until a recent paper in the journal Marine Biodiversity Records, it had not been officially identified anywhere in the Northern Hemisphere.
In 2009, MBARI researchers worked with marine biologists at the Pacific Shark Research Center and the California Academy of Sciences to identify a new species of ghost shark in the Gulf of California.
Some of these same scientists had also seen ghost sharks during remotely operated vehicle dives off Central California.
They weren’t sure about the exact species, but they knew the fish did not look like either of the two species of ghost sharks previously identified from off the California coast.
In the recent paper, the authors presented evidence that the unidentified ghost shark they were seeing around Monterey Bay was, in fact the same species that had previously been identified only in the Southwestern Pacific.
The paper cited three different chimaera experts who viewed the video from MBARI remotely operated vehicle dives and said that they believed the fish was the pointy-nosed blue chimaera.
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Amber N. Reichert et al. 2016. First North Pacific records of the pointy nosed blue chimaera, Hydrolagus cf. trolli (Chondrichthyes: Chimaeriformes: Chimaeridae). Marine Biodiversity Records 9: 90; doi: 10.1186/s41200-016-0095-5
This article is based on a press-release from the Monterey Bay Aquarium Research Institute.
