A Better Understanding of Coral Reef Ecosystems

Pelagic predators such as these barracuda, Sphyraena qenie, are part of the coral reef ecosystem in the U.S. Line Islands (NOAA Photo by Kevin Lino).
A team of scientists have embarked from Hawai'i on a three-month survey of coral reef ecosystems at Johnston Atoll, the U.S. Phoenix Islands, the islands of American Samoa, and the U.S. Line Islands in the tropical Pacific Ocean. The overarching objective is to better understand the coral reef ecosystems of these areas, many of which are seldom explored. The research expedition is part of a regular monitoring program, conducted by the Coral Reef Ecosystem Division (CRED), headquartered in Honolulu, Hawai'i. The expedition is supported by NOAA's Coral Reef Conservation Program and involves extensive cooperation among NOAA scientists and research partners, including the University of Hawaii Joint Institute for Marine and Atmospheric Research (JIMAR), the U.S. Fish and Wildlife Service, San Diego State University, and the Papahānaumaokuākea Marine National Monument.

The research expedition will be carried out from February 27 to May 24, 2012 aboard the NOAA ship Hi'ialakai. Under the leadership of Chief Scientists Dr. Jill Zamzow, Dr. Bernardo Vargas-Angél, and Jamison Gove, a diverse team of researchers will be conducting multidisciplinary coral reef ecosystem surveys, assessing the status of fishes, corals, algae, marine invertebrates, and the oceanographic conditions in which these organisms exist. The scientific data collected during the three-month research expedition will enable informed and effective implementation of ecosystem-based management and conservation strategies for coral reef ecosystems, helping to ensure their protection for generations to come.

Sunday, September 19, 2010

Giant Trevallys

By Kaylyn McCoy

My favorite part about visiting the Northwestern Hawaiian Islands is being able to see the giant trevallys, also known as uluas, or Caranx ignobilis. Luckily, I’m a member of the fish team, so it’s my job to watch these guys swim around. Living on Oahu, I don’t see too many big fish, but out here is a different story. These atolls are so remote that these fish thrive.
A school of Caranx ignobilis in the shallows at French Frigate Shoals.

These uluas, also known as jacks (family Carangidae) are very curious, and usually come very close. It’s quite impressive to see a meter plus long fish swim directly up to you and stare you down while it swims around you. These species are the largest of the genus Caranx, and can grow up to 1.7 meters and weigh over 60 kilograms; that’s a lot of fish!
A curious fish comes in for a closer look.


The juveniles spend most of their time in estuaries or lagoons, while the adults can be found on the forereefs. They are usually silver in color, but the older adults can be mostly black. Giant trevallys are apex predators, and eat smaller fish and a variety of crustaceans. They use a varitey of hunting techniques, and have been known to follow sharks to ambush their prey.
It seems this ulua got a little too close to a shark.

Part of the equipment we carry with us on our fish dives is a monopod, or a meter long stick that we use to position a camera for benthic photos. Yesterday, I had a fiesty Caranx ignobilis, or CAIG (fish team short-hand: first two letters of the genus name, first two letters of the species name) actually bite the monopod while I was taking photos!
Paula Ayotte takes pictures using the monopod while several giant trevally circle her.

These fish are usually attracted to shiny objects, thinking that the shiny object is a small delicious fish. I’ve seen one nip the top of my buddy’s head as it went for a shiny sticker on his snorkel. These fish tend to follow us around on a dive, as we swim from one transect to the other, and they even hang out with us on our safety stop.
Several giant trevallys circle a shiny reel as it bobs at our safety stop.

Rumor has it that the brave/crazy ones will actually try to bite the propellers on the small boats…while they are spinning! It’s never a boring dive with these guys around!
Posted by NOAA CRED at 8:21 AM

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