Dive 05: Jarvis Island
May 5, 2017
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Dive 05: Oreo Fish

This oreo fish, seen while exploring near Jarvis Island, gets its common name not from the cookie, but from its scientific name, as it belongs to the family Oreosomatidae. While these fish appeared abundant at the dive site, they unknown from this part of the world before 2005. Video courtesy of the NOAA Office of Ocean Exploration and Research, Mountains in the Deep: Exploring the Central Pacific Basin. Download (mp4, 24.9 MB)

Today we dove near Jarvis Island, a 4.5 square kilometer (1.7 square mile) uninhabited island just south of the Equator. We investigated a ridge off of the southeast side of the island. From the moment we entered the water until the remotely operated vehicles Seirios and Deep Discoverer (D2) returned to the surface, we were surrounded by rich biodiversity.

On our descent, we observed an exceptionally high number of pelagic animals – indicating that there may be some local upwelling around the island. Midwater fish were abundant, especially around 500-700 meters. We also saw numerous arrow worms, some comb jellies, shrimp, and mysids during the descent. Throughout the dive, we saw some pelagic animals near the seafloor as well, including numerous siphonophores and many pelagic holothurians that appeared to be stuck on seafloor features.

The dive transect crossed several high-density communities including a low-diversity community of scleractinian coral; multiple instances of crinoid, urchin, holothurian, and ophiuroid communities; a landscape of polychaete tube mounds; and fields of primnoid sea fans. The dive closed on an unusual umbrella-shaped pedestal that was densely covered with corals and sponges, with a large school of Randall's snappers nearby. Other highlights of the dive were a sand tiger shark and observing a group of ophiuroids capture and eat a squid.