Benham Rise: A Call For Connectivity and Action

Beyond The Journey

Benham Rise, an undersea territory, is located east of Luzon where its shallowest part, Benham Bank, is at least 50 meters deep. Its name originated from the surveyor Andrew Benham who first mapped the region in 1933 [2].

April 12, 2012 marks the United Nations Commission on the Limits of the Continental Shelf (UNCLCS) validating the additional 13-million hectare extended continental shelf (ECS) of Benham Rise as part of the Philippines' continental shelf. Now, our maritime rights on the region stretched from the original 11.4 million hectares (within the 200 nm Exclusive Economic Zone) to 24.4 million hectares, nearly equal to our land expanse - currently at 30 million hectares [1, 2].

What is clear here is that Benham Rise is not considered a part of the Philippine national territory but the country is bestowed "sovereign rights" (less than "sovereignty") over the region, allowing it exclusive and superior authority to explore, develop and utilize its living and non-living resources [4]. 

Map of Benham Rise showing the acquired extended continental shelf (ECS).

It could have been a viewed as swift success. The claim, however, was pursued tenaciously, thanks to over a decade worth of work by a team of public servants, scientists and legal experts. What was once a workshop in 2001 forged the first major successful claim under the United Nations Convention on the Law of the Sea (UNCLOS) [1].

Recent Glimpse

Last May 2016, Oceana, Earth's NGO solely for marine conservation, joined government scientists from the Bureau of Fisheries and Aquatic Resources (BFAR), University of the Philippines, Philippine Coast Guard and Philippine Navy on an expedition in Benham Bank. They did oceanographic, benthic (study of the seabed) and microbiological surveys, and documented large marine life [1].

They were thrilled to discover 100% coral cover in the surveyed area, which, if highly unlikely, is rare in the Philippines. According to Oceana’s Marine Scientist, Marianne Pan Saniano, the bank had crystal clear waters (personal communication, March 23, 2017). Rightfully so, the team reported the bank to hold a diverse, multitude of marine organisms [2].

The Twilight's Promise

The team documented at 50 m depth a huge ‘mesophotic’ or deep-sea reef ecosystem laden with impressive coral cover and associated fauna.

A colony of foliose corals at a minimum depth of 50 meters in Benham Bank. (Oceana / UPLB)

As shallow water reefs continue to degrade, scientists turn their hopes to the mesophotic zone. It’s also called the “twilight zone” as it signifies the transition between brightly lit surface waters and dark, deeper depths. The mesophotic zone (30-150 m) is often deemed as extensions of shallow-water reef ecosystems, dominated by light-dependent corals, sponges and algae [6].

Though widespread and diverse, mesophotic coral ecosystems (MCEs) remain largely unexplored. The good news, though, is that new technologies allow deeper exploration of our oceans.

One hypothesis that incited the interest of studying the mesophotic zone is the ‘deep reef refugia’ hypothesis which underscores its potential for replenishing  or “re-seeding” damaged reef ecosystems [6]. In one study, MCEs, seagrass beds and mangroves are found to likely to provide brood stocks - replenishing and sustaining damaged, heavily exploited nearshore reefs. Such was the case in the spawning aggregations of the red hind grouper (Epinephelus guttatus) which re-seeded shallow waters when it produced larvae in deep waters off US Virgin Islands [10].

Studies in the Indo-Pacific MCEs have also shown the region to hold diverse benthic communities. They also serve as refuge to shallow-water coral reef species experiencing environmental stress like light-enhanced warm water bleaching [9].

Using an autonomous underwater vehicle (AUV), scientists surveyed, at depths of 50 to 65 m, anemonefishes at Viper Reef and Hydrographers Passage in the Great Barrier Reef. The findings show that at least some species of host sea anemones and anemonefishes occur across a wider bathymetric range, stretching from reef flats and slopes into the mesophotic zone. This supports the hypothesis that mesophotic reefs contain many species only thought to be common to shallow-water reef habitats [8].

Over the years, the idea of the zone’s emerging importance has taken momentum. Take Papahanaumokuakea Marine National Monument in Hawaii where divers used mixed-gas dives. The study revealed that its mesophotic reefs host an unprecedented rate of endemism. At depths of 30 to 90 m, about 46% of reef fishes are endemic, significantly higher than previous shallow water surveys in the area, and almost two-fold higher than in any other tropical region [7].

It is possible to unearth high endemism rates as well in other protected, uncharted mesophotic regions such as that of Benham Rise, suggesting the importance of spreading awareness of its existence. 

MCE research is slowly gathering speed and with its rise, comes the critical need to better understand biodiversity patterns across depths, the connectivity of oceanic regions, and consequently create an  informed, holistic future reef policies and management practices [8, 10].

Bold is Now

Recently, the Philippine Department of National Defense disclosed that Chinese vessels' were spotted in the area, whose unusual movement pattern suggests survey activities rather than merely passing through the region [5].

Aside from this pressing concern, the region is also vulnerable to climate change, urging the Philippine government to assert its rights over the region through biodiversity research, creating a management framework, and consequently declaring Benham Rise as a ‘no-take’ zone [2]. 

We don’t know yet but it might be the last pristine waters we’ll ever lay eyes on. 

Oceana has an online petition urging everyone to declare their support for the protection of Benham Rise. If you are for it, then make your voices heard and put your thoughts into action!

A lone Philippine flag sits in front of a Sarcophyton soft coral at a deepwater reef in Benham Bank. (Oceana / UPLB)

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[1] Batongbacal, J. L. & Carandang, E. P. (2012). Benham Rise: How the Shelf Was Won.  National Mapping and Information Authority (NAMRIA).

[2] OCEANA (2016). Now is the Time to Protect Benham Rise [Press Release]. Retrieved from http://bit.ly/2o8NDX9 

[3] Perez, A. (2016). Exploring Philippines' Benham Rise Region for Fisheries Development and Management [PowerPoint slides].

[4] Francisco, K. (2017, March 18). Rappler IQ: Fast facts: What you should know about Benham Rise. Rappler. Retrieved from http://bit.ly/2o8Dzxf

[5] Batongbacal, J. (2017, March 14). Opinion: Understanding the issue about Chinese survey vessels in Benham Rise. GMA News Online. Retrieved from http://bit.ly/2nfaoU8

[6] Baker, E. K., Puglise, K. A., & Harris, P. T. (Eds.). (2016). Mesophotic coral ecosystems – A lifeboat for coral reefs? The United Nations Environment Programme and GRID-Arendal, Nairobi and Arendal, 98 p. Retrieved from http://bit.ly/2oemgrf

[7] Kane, C., Kosaki, R. K., & Wagner, D. (2014). High levels of mesophotic reef fish endemism in the Northwestern Hawaiian Islands. Bulletin of Marine Science, 90(2). http://dx.doi.org/10.5343/bms.2013.1053

[8] Bridge, T., Scott, A., & Steinberg, D. (2011). Abundance and diversity of anemonefishes and their host sea anemones at two mesophotic sites on the Great Barrier Reef, Australia. Coral Reefs, 31, 1057-1062. doi: 10.1007/s00338-012-0916-x

[9] Bridge, T. C. L., Fabricius, K. E., Bongaerts, P., Wallace, C. C., Muir, P. R., Done, T. J., & Webster, J. M. (2012). Diversity of Scleractinia and Octocorallia in the mesophotic zone of the Great Barrier Reef, Australia. Coral Reefs, 31, 179-189. doi:10.1007/s00338-011-0828-1

[10] Bridge, T. C. L., Hughes, T. P., Guinotte, J. M., & Bongaerts, P. (2013). Call to protect all coral reefs. Nature Climate Change Volume, 3(6), 528-530. Retrieved from http://bit.ly/2nflb0v