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Explore21: Diving off Borokua Island

From the Field posts

This month, Museum Curator John Sparks is leading The Explore21 Solomon Islands Expedition. A part of the Museum's Explore21 initiative, this three-week research journey is headquartered aboard the Research Vessel Alucia.

Expedition member Chris Filardi, who is the director of Pacific Programs in the Museum’s Center for Biodiversity and Conservation, recently wrote in with this dispatch.

Chris Filardi Explore21

Chris Filardi


Now we are heaving to* along the edge of Borokua Island, an isolated, dormant volcanic cone poking up out of mile-deep tropical ocean. Uninhabited, with eerie whispers of winds that blow over this headhunter's waystation, the place is truly spectacular, a last wild island full of life and mystery.

Alucia hi-resolution image

The Research Vessel Alucia allowed Museum researchers to explore the waters, mangrove forests, and coral reefs of Solomon Islands in 2013

© AMNH/John Sparks


Strange bedfellows wonderfully texture Borokua’s natural communities. Pale Imperial Pigeons, huge canopy birds on the mainland, are here on the ground next to chicken-like megapodes, scuffing in the duff.

Imperial Pigeon Explore21 Borokua

Imperial pigeon, Borokua Island, Solomon Islands, 2013

© AMNH


Endemic goshawks, Osprey just like those around New York City, and Brahminy Kites, elegant raptors that range all the way to southern Asia, soar alongside countless hornbills pumping across the green outer slopes.

Hornbill Borokua Explore21

A hornbill photographed in the Solomon Islands by Museum researchers, 2013

© AMNH


Black cormorants trade over the central bay as crocodiles disappear among the coral heads, and then as the night curtain of real, far-away dark falls, a din of insects and frogs rises to a whir that goes on until dawn. A volcano that burst itself up from the lightless abyss created a land redolent of Eden.

And what we are experiencing above the waterline is literally the tip of a living (coral) iceberg.

Borokua Explore21 Coral

Coral cover across the reefs ringing Borokua Island is exceptionally dense, a reflection of the remote setting and coral ecologies that appear relatively resilient to oceanographic shifts in temperature and ocean chemistry that are killing corals around the world.  Whether this is the result of species richness and composition of the reefs, geography, evolutionary history, or some combination of factors is unknown.  Maintaining these areas for study, for the food and other resources they provide, and for wonder is a global priority.

© AMNH


Steep slopes that fall away from Borokua’s leafy ridgelines continue on and on into the depths. Near shore, in the moving light of the shallows, some of the richest and most vibrant coral gardens on Earth thrive. From the hill and cloud forests down into the reefs, there are terrestrial and marine protected areas. Programs by the Museum’s Center for Biodiversity and Conservation are supporting tribal owners’ efforts to conserve these rare coral-to-cloud forest linkages. 

Our research goes deeper, with the subs, but also with specialized deep diving that extends the limits of free-swimming human exploration. Because of risks inherent to our remote setting, we are only descending half of the 400-plus feet that deep divers can safely reach. Even so, getting 200 feet down in the Solomons is providing some of the first collections near or at the mesophotic zone, where light is filtered to pure, fading blue, and the ecological communities are from a a realm rarely surveyed by scientists.

Borokua, Solomon Islands

© AMNH


The bulk of marine science probes only a thin veneer of the vastness of the oceans.  Most work is done in recreational dive realms, with the majority not exceeding 60 feet below the surface. Marine biologists are just beginning to seek training, experience, and new technologies that deepen the envelope of SCUBA. The results are exposing new dimensions in marine ecology and a steady stream of new species that reflect poorly known living layers in the sea.

The degree of species turnover—the rate of species that drop out across depth (or any other gradient such as latitude or altitude) as other species are encountered—from the photic zone through the mesophotic and aphotic zones is very poorly known anywhere and is unexplored in the areas where we are diving. Describing new species from these deeper areas is a true realm of discovery that few scientists and institutions are equipped to probe. 

Once back at the Museum, observations, specimens, images, and ecological data will inform many months of expert comparative and molecular work that can result in a clearer understanding of ecological communities and the variety of life as one slips below the relative familiarity of coral reefs.

Ultimately, understanding these patterns in the complex and healthy systems of the Solomons can give us a sense of what we should strive for in management around the globe. Out here, even before we “know” all we have uncovered, rising from a deep dive in the evening to the timeless hum of life on Borokua is a reminder that the work of the Museum must bridge efforts of discovery with the hard work of conservation. Without this dual purpose, all of the wonder and energy of this trip may simply embellish an epitaph for what once was.

* “heaving to” in this context means we are drifting under power against the coast without anchoring, because the coast drops off quickly

Read more dispatches from the Explore21 researchers.

Tags: Explore21

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