By Emily Fisher
The Canary Islands are home to rich underwater ecosystems that are among the most vibrant in the world. Colorful gorgonians, black coral and rare sponge forests thrive here, thanks to a ban that has prevented bottom trawling in the region since 2005.
In 2009, the Ranger set sail for the Canaries, documenting this special place and many of the unusual species that call it home. Over two months, the crew found a dozen species never before seen in the Canary Islands, and filmed many rare species, such as three-foot-tall glass sponges, Venus fly-trap anemones and lollipop sponges.
The Canaries, a necklace of volcanic islands 60 miles off the coast of northwest Africa, were discovered in the first century A.D. by an explorer commissioned by Roman emperor Augustus. Centuries later, the seafloor surrounding the islands is still mostly unexplored.
The Ranger’s crew completed a total of 81 dives, including 32 with divers and 49 with an underwater robot (ROV) that dove as deep as 2,300 feet – a Ranger ROV record.
In another milestone, Oceana filmed the Saharan seamounts, the southernmost seamounts in Spain, for the first time in history. The crew used the ROV to gather images almost 2,000 feet below the surface of the sea. The seamounts rise from the ocean floor 13,000 feet below the surface.
The seamounts were decorated with caves, overhangs and cracks hosting deep-sea sharks, rays and wreckfish, as well as fields of sponges, gorgonians and corals. Especially common in the area were sixgill sharks, which are deep-sea sharks measuring up to 16 feet long and weighing up to 1,000 lbs.
The crew also spotted two rare species closely related to the famously overfished orange roughy: the Mediterranean silver roughy and the Darwin’s slimehead.
Not all of the crew’s discoveries were positive. The waters around the Canary Islands are oligotrophic, meaning they contain few nutrients to sustain life. As a result, any human
encroachment – coastal development or fisheries, for example – has a significant impact on the ecosystems. In shallow coastal areas, the crew found a surprising dearth of fish and a proliferation of lime urchins, one of the archipelago’s biggest threats. The urchins devour the island’s algae cover, which is food for many other species.
When the crew visited La Palma Marine Reserve, however, the contrast was visible.
“Once again we confirmed the benefits of creating protected areas or reserves,” photographer Eduardo Sorensen wrote in the expedition diary from that day. “As soon as you submerge into the reserve, a healthy ecosystem becomes evident.”
Not only are protected areas visibly healthier, they are also required by the U.N. Convention on Biological Diversity, which states that 10 percent of the global marine environment be protected by 2012. Only 0.15 percent of the islands’ sea surface is protected. Overall, 2.7 percent of the European Union’s waters are protected.
In order to mount a campaign to create new protected areas in the Canaries, it is crucial to first determine what’s at stake in the dark depths of the sea, according to Riki Aguilar, director of the expedition. "The lack of knowledge of the communities existing at great depths is one of the biggest problems when it comes time to decide which areas must be protected,” he said.
Now that the crew is back on the Spanish mainland, they are working on a scientific report on the state of Canarian marine ecosystems, drawing conclusions about the state of the seabeds and the threats they face.