Coming to a close

We arrived back in Saipan on May 7, concluding a monumental expedition to Wake, Guam and the Commonwealth of the Northern Mariana Islands.  We all have mixed emotions.  On the one hand is it nice to sleep in our own beds, see our loved ones, and spend some time on dry land again.  On the other hand we all miss the water and the islands we have come to know and love so  much.

We will spend the next several weeks error checking all the data we collected and putting together our reports of all that we saw and discovered.  Our final cruise report should be ready in a month or so.  Stay tuned for a link to that and follow along both here and on our FaceBook page for continuing research and future expeditions.

Where are all the little guys?

Did you know that a coral reef ecosystem contains thousands of creatures besides fish and coral? We just can’t easily see them because many are cryptic, nocturnal, or simply too small to easily see.   And yet, these invertebrates make up most of the diversity in a coral reef system. So how do we monitor and assess all the organisms that we can’t see? Our answer is the Autonomous Reef Monitoring Structure, otherwise known as ARMS.

ARMS were developed as a long term sampling and monitoring device to detect, measure, and monitor the diversity of cryptic invertebrates in reef systems over time. They are designed to simulate a reef environment.  The layers of the ARMS have both open and closed spaces which provide both hard settlement areas and small hiding holes for various kinds of small organisms. Our ARMS are installed by two divers and remain on the sea floor for 2 years collecting organisms before we remove them an analyze their contents.

Overtime, critters will start to colonize the ARMS. Sessile invertebrates such as sponges, tunicates, and bryozoans, will recruit to and settle on them. Small motile critters such as majid crabs, squat lobsters, polychaetes, brittle stars, and nudibranchs will eventually make their way within the layers and call the ARMS their new home. It’s like a little reef apartment building.

An aspiration of the ARMS project is to create indices of biodiversity across diverse habitat gradients around the world. ARMS currently exist in Moorea, Australia, Brazil, Hawaii, American Samoa, and the U.S. Pacific Islands and will soon be deployed in Papua New Guinea, Panama, Cayman Islands, Puerto Rico, and the Seychelles. MARAMP 2009 added Wake Atoll, Guam, and Saipan, Pagan, and Maug in the Marianas to the ever growing list. This global ARMS effort is a part of the Census of Marine Life, CReefs project.

Fishy Fun at Farallon de Pajaros

The island of Farallon de Pajaros (aka Uracus), is the northernmost island in the Mariana Archipelago. It is also considered the most volcanically active. Although, the last major eruption was recorded in 1967, undersea vents and the nearby Makhahnas seamount are still reportedly active. Its steep slopes are stark, but populated by thriving seabird communities, which nest on the platforms created by past lava flows.

Underwater, the relatively young reef ecosystem is populated by scattered coral colonies. In some areas, the corals are attached to boulders surrounded by black sand, but in others they are attached directly on the dark volcanic rock substrate along steep walls. While the reef here is not as well developed as others in the chain, the fish population here was surprisingly robust and interesting. (Photo: R. Schroeder)

The Fish Team was able to document two important findings at this island: the continued presence of the endemic yellow-crowned butterflyfish, Chaetodon flavocoronatus, first noted during the 2007 MARAMP, and a species of fish previously not recorded in the Marianas, the saddleback hogfish (Bodianus bilunulatus).

Yellow-crowned butterflyfish (Chaetodon flavocoronatus) Photo: M. Nadon

Black Jack (Caranx lugubris) Photo: V. Brown

White-tip Reef Shark (Triaenodon obesus) Photo: M. Ferguson

Those were not the only interesting finds of the day, because every REA site provided close encounters with curious large predators from friendly black jacks, Caranx lugubris, to more intimidating great barracuda (Sphyraena barracuda), white-tip reef sharks (Triaenodon obesus), and gray reef sharks (Carcharhinus amblyrhynchos).

Great barracuda (Sphyraena barracuda) Photo: V. Brown

But clearly, the highlight of our day had to be the entertainment we received during our safety stop, as we were visited by a school of more than a hundred Spadefish, also known as Batfish, or Platax teira to the scientists on the Fish Team. These beautiful, somewhat goofy fish surrounded us as we floated at fifteen feet. They swam in circles around us, first one way, then another, boldly approaching close enough to stare into our eyes, almost close enough to touch. Their antics amused and delighted us, bringing a bright ray of light into an otherwise cloudy, overcast day. The evening was spent sharing pictures and stories of our encounters. It was definitely a memorable experience for both the Oceanography and REA teams who encountered these gregarious fish.

Spadefish (Platax teira) Photo: M. Ferguson

Spadefish School Photo: R. Schroeder

Thanks for Visiting! Photo: V. Brown