For decades, overfishing and trawling – dragging the ocean bottom with heavy nets – had been devastating parts of an underwater mountain range in the Pacific Ocean near Hawaii, wrecking deep-sea corals and destroying much of their ecological community.
But now, after years of protection, scientists see signs that this once-fertile area known as the Hawaiian-Emperor Seamount Chain is making a comeback. The practice of trawling has devastated seamounts around the world, and scientists have generally believed that an ecological recovery was unlikely. However, in the case of the Seamount Chain, there seems to be a glimmer of hope.
Trawling was substantially reduced in 1977 when the U.S. claimed the seamount as part of its Exclusive Economic Zone. The establishment of the zone in this region has provided protection for these sites for close to 40 years, providing a unique opportunity to look at recovery on a longer time scale.
Through multiple research visits, researchers sent an autonomous underwater vehicle to take photographs of the surrounding coral reefs. After analyzing 536,000 images, apart from seeing remnant trawling scars on the seafloor, the researchers also saw baby coral springing up in those areas. On top of that, they could see coral regrowing from fragments on fishing nets that were left on the seafloor.
Most importantly, they found evidence of a few precious areas that were not harmed by the trawling. These untouched areas are crucial to further populating the seamounts with a variety of fauna. It’s too early to say how long it took for the new coral to arrive and whether the area will return to its former glory, but the findings provide critical knowledge for policymakers examining the effectiveness of protecting such vulnerable ecosystems.