A little-noticed part of the ocean — the mesopelagic, better known as the “twilight zone” — is suddenly being priced into global ocean policy. At the Our Ocean Conference in Mombasa, Fiji and Panama launched a voluntary Mesopelagic Zone Conservation Challenge that asks governments to apply precaution before mid-water fishing expands and before seabed mining ambitions harden into permits.
The economics are the subtext. The mesopelagic sits roughly 200 to 1,000 meters below the surface and has long been treated as a biological black box. But improving gear, rising demand for fish protein, and the market for omega‑3 inputs are pushing industry to look deeper. Ocean Conservancy says emerging commercial interest is tied to products such as fish meal and health supplements, even as climate change and deoxygenation reshape the layer’s ecology (Ocean Conservancy).
A carbon pump with a policy gap
What makes the initiative notable is not that it creates new marine protected areas, but that it tries to set “rules before the rush.” In the Ocean Conservancy statement, Chris Dorsett, the group’s vice president of conservation, describes the twilight zone as “a gateway between the ocean’s surface and the deep sea,” warning that the layer is “under threat from climate change” as well as “growing commercial interests” (Ocean Conservancy).
Panama positioned the challenge as part of a whole-water-column approach. “Without a healthy, functioning twilight zone, the health of the entire ocean is at risk,” said Eduardo Carrasquilla, administrator general of Panama’s aquatic resources authority, adding that protecting the mesopelagic “helps the ocean to lock away carbon” (Ocean Conservancy).
Food security, not just biodiversity
For coastal states, the twilight zone is also upstream of everyday protein. Ocean Conservancy’s analysis highlighted a fishery linkage in the host country: species from the mesopelagic zone can make up “as much as 81% of swordfish diets and 46% of yellowfin tuna diets,” tying the layer to Kenya’s offshore catches and associated incomes. Fiji framed its support through community dependence. “As a Pacific island state deeply dependent on healthy marine ecosystems, Fiji strongly believes in the critical importance of protecting the ocean twilight zone for the long-term health of our ocean and the well-being of Pacific communities,” said Sivendra Michael, Fiji’s permanent secretary for environment and climate change (Ocean Conservancy).
What countries are committing to
The challenge is designed as a checklist for “good governance before new extraction.” Participating governments commit to applying a precautionary approach to expanding fishing and other potentially harmful activities, advancing scientific understanding, building management frameworks, and advocating for recognition of the mesopelagic’s importance in international decision documents, including the UN General Assembly’s Sustainable Fisheries Resolution (Ocean Conservancy).
Portugal and Vanuatu also signaled support, and one reason the pledge is likely to resonate is uncertainty: Kristin Kleisner, associate vice president of ocean science at Environmental Defense Fund, warned that commercial interest is rising even though researchers “have only cataloged a fraction of the species living in this layer” (Ocean Conservancy).
Science and global governance, in parallel
The Fiji-Panama pledge tracks closely with a separate move at the institutional level. The International Union for Conservation of Nature’s World Conservation Congress adopted Motion 035 on the protection of mesopelagic ecosystem integrity, which urges members to apply “a precautionary pause on any expansion of mesopelagic fishing or other ocean activities potentially impacting mesopelagic species and ecosystems” until structure-and-function, governance frameworks, and biodiversity safeguards are in place. The motion records that the mesopelagic comprises only 20% of the ocean by volume yet sustains an estimated 50–90% of its fish biomass, and that vertical migrations move an estimated two to six gigatons of carbon a year — “double the emissions produced by cars worldwide annually.”
The science backbone for that policy push has been built largely by the Woods Hole Oceanographic Institution (WHOI), whose multi-year Ocean Twilight Zone project was set up to inform high-seas decision-making before commercial extraction scales. “We need to get those answers quickly because the twilight zone is under threat,” said WHOI senior scientist Heidi Sosik, lead investigator on the project, in a WHOI announcement. “We can’t turn back the clock on decades of overfishing in regions of the ocean that once seemed inexhaustible. But we can take a different path this time. Smart policies arise from sound data.” The Fiji-Panama challenge effectively asks signatory governments to act on that principle now, rather than after extraction.
OceanVines exists to illuminate the inner sparks of every life we touch through our efforts in ocean conservation and education. For Asia, the twilight zone debate is a reminder that stewardship is no longer just about protecting coastlines — it is about governing the full vertical ocean, from the sunlit surface down to the layers that quietly stabilize the climate system.
Together, we celebrate The Greatest Good.