Exploring Mañagaha Island’s nighttime treasures

On Friday, April 26, two Northern Marianas College classes traveled to, and camped overnight on Mañagaha Island, exploring the island and its adjacent Marine Sanctuary ecosystems.

Camping overnight allowed the Marine Biology (BI 103) and Natural History (BI 201) students to view and appreciate the nighttime land and coral reef life, including the crabs, fishes, octopuses, and other organisms that emerged to feed, after hiding in coral crevices and sandy substrates all day.

Several of the trip’s participants were not only NMC students; there were also high school students attending the NMC-associated Northern Marianas Academy. The field trip was the capstone of these students’ 16 weeks-long semester science classes.

The Managaha Marine Conservation Area was passed into law in 2000. Instructor John Furey, who has taught marine biology courses at NMC since 1986, and all members of this semester’s classes, can readily affirm that the purposes for which the aquatic area around the island was made into a marine sanctuary are definitely being fulfilled.

Under the direct management and enforcement of the Division of Fish and Wildlife, the finfish resources of the MMCA have steadily improved since its inception. Large Mafute, large Hangun and Tataga, and other large fishes attest to the sanctuary’s lack of constant fishing. These commonly-targeted fishes, now able to reach adult size, will spawn hundreds of thousands of fish larvae that will drift with the currents into adjacent, non-sanctuary, fishing grounds. They also serve to entertain and fascinate each of Mañagaha’s tourists that are adventurous enough to don the needed mask, snorkel, and fins required to see and appreciate the area’s remarkable sea life.

The student observers took notes on the night’s net-captured and then released species, discussing each organism’s unique characteristics and the ecological roles they play in both the islands’ terrestrial and the marine environments. These records included nighttime shore organisms, including the hundreds of Ghost Crabs (Ocypode sp.) which came out from their holes to feed upon whatever that particular evening’s spring tide washed ashore. Also recorded were the island’s eerie nighttime crying calls from the young fledglings of Managaha’s nesting Wedge-tailed Shearwater birds (Puffinus pacificus), whose parents arrive after midnight to feed them after a long day’s catch of flying fish, squid, and other near-surface sea life.

Land plants observed and recorded included Cassythia filiformis, an interesting native parasitic vine similar to a common invasive plant called ‘Dodder’; Hernandia sonora, a large indigenous tree with interesting leaves and flowers commonly known as ‘Nonak’; and Neisosperma oppositifolia, a native tree whose parts are used medicinally throughout the Pacific and which is commonly called ‘Fagot’.

Fish life observed included one of the colorful and oddly-shaped Moorish Idols (Zanclus cornutus), a small poisonous but unidentified scorpionfish, the above-mentioned surgeonfishes, Hangun (Naso literatus) and Tataga (Naso unicornis), the above-mentioned emperor fish, the Black-spot Mafute (Lethrinus harak), and numerous and active, but unidentified Damselfishes.

The troop barbecued a variety of marinated dishes that they had brought and, to the accompaniment of a ukulele and a guitar, sang every song that anyone knew until about three in the morning. After a brief sleep, it was time to head back to Saipan to visit—and to shop—at this year’s fantastic CNMI Flame Tree Arts Festival. (John Furey)