Ocean Policy · Mesopelagic Conservation

Fiji and Panama Launch Global Challenge to Protect the Ocean’s Twilight Zone

Two governments have become the first to join the Mesopelagic Zone Conservation Challenge, a voluntary pledge covering the water column between 200 and 1,000 meters. The layer feeds the fisheries above it and moves carbon into the deep, and almost nobody has agreed to manage it.

By SEVENSEAS Media | Ocean Conservation

Two governments have put their names to the first international pledge written specifically for the ocean’s twilight zone. At the Our Ocean Conference in Mombasa, Kenya, on 18 June 2026, Fiji and Panama launched the Mesopelagic Zone Conservation Challenge, a voluntary commitment covering the water column that runs from roughly 200 to 1,000 meters (220 to 1,100 yards) beneath the surface. Signatories agree to apply a precautionary approach to fishing and other extractive activity in that layer, and to fund the science needed to understand what is down there before deciding what to do with it.

The initiative is led by Ocean Conservancy alongside the Marine Conservation Institute and the Environmental Defense Fund. Portugal and Vanuatu did not formally join at launch but publicly endorsed the challenge’s goals. It follows Resolution 035 on mesopelagic ecosystem integrity, which Ocean Conservancy says was adopted at the 2025 IUCN World Conservation Congress.

The framing matters. The twilight zone is not remote in the way the abyssal plain is remote. It sits directly beneath the fisheries that coastal economies already depend on, and its inhabitants come up to meet the surface every night. Ocean Conservancy’s vice president of conservation, Chris Dorsett, described it in the launch materials as a gateway between the surface ocean and the deep sea, and argued that climate pressure and commercial interest in fish meal and health supplements have made it a zone that urgently needs attention.

The layer that feeds the fisheries above it

Whales, dolphins, seabirds, sharks and large predatory fish all draw on twilight zone prey. Tuna and swordfish are particularly dependent on the lanternfish, squid and shrimp that populate it. That dependence is not abstract for the country that hosted the conference. Ocean Conservancy analysis cited at the launch found the mesopelagic zone to be the primary food source for Kenya’s tuna and swordfish fisheries, with twilight zone species making up as much as 81 percent of swordfish diets and 46 percent of yellowfin tuna diets. The organization reported the Kenyan industry earning 3.3 million US dollars in 2023 and supporting hundreds of local fishermen.

Those figures come from Ocean Conservancy’s own analysis and have not been independently verified by SEVENSEAS Media. The broader scale of the zone carries a similar caution. The mesopelagic accounts for about 20 percent of the ocean’s volume, and by some estimates holds upwards of 90 percent of all fish biomass in the sea. That estimate is widely repeated and comes with a wide margin of uncertainty, which is itself part of the argument the challenge is making.

The carbon pump nobody manages

The second case for protection is climatic. Every night, mesopelagic animals migrate upward to feed and return before dawn, carrying carbon downward in their bodies and their waste. It is one of the largest daily movements of biomass on the planet, and it functions as a biological pump.

Everyday, billions of mesopelagic animals migrate to the surface to feed, transporting carbon back down, creating the ocean’s biological carbon pump.

Lance Morgan, President, Marine Conservation Institute

Morgan put the transfer at an estimated two to six gigatons of carbon per year moving from the surface into the deep sea, and said the low end of that range is roughly double the annual emissions of every car on Earth. Most of that carbon, he said, stays in the twilight zone or sinks further, keeping it out of the atmosphere. The width of the range, a threefold spread between the low and high estimates, is a reasonable indication of how poorly constrained this flux still is.

Why the fishing industry is looking down

Commercial pressure on the zone is not hypothetical, and it is partly a knock-on effect of climate change higher in the water column. Populations of small surface fish such as anchovies are expected to decline in a warming ocean, and the feed industry is already scanning for substitutes.

Lanternfish are the obvious candidate. Smaller than a pencil and rich in omega-3 fatty acids, they account for around 60 percent of all deep-sea fish, with a global biomass estimated at roughly 600 million tons. Aquaculture feed, pet food and human health supplements are the markets driving interest. Improving gear and vessel technology is closing the gap between interest and capacity. Alongside fishing, the zone faces warming waters, deoxygenation, and the prospect of deep-sea mining operating through it.

The knowledge gap is the argument

What distinguishes this initiative from most conservation asks is that it is not built on a settled body of evidence. It is built on the absence of one. Kristin Kleisner, associate vice president of ocean science at the Environmental Defense Fund, said the alarming part of rising commercial interest is how much remains unknown: only a fraction of the species living in the layer have been catalogued, and their role in ocean food webs and carbon cycling is not fully understood. Her position is that enough is known to justify caution, not enough to justify extraction.

That is a precautionary argument, and precautionary arguments have historically fared badly against commercial ones in fisheries governance. Getting the language into a UN General Assembly resolution, as the challenge intends, is the point at which it would begin to carry weight.

Portugal and Vanuatu signal support

Beyond the two founding governments, Portugal and Vanuatu acknowledged the importance of the zone and backed the challenge’s overarching goals without formally joining. Salvador Malheiro, Portugal’s secretary of state for fisheries and maritime affairs, called leading by example the only effective route to advancing international ocean governance, and said Portugal expected to work with partner nations on turning the challenge’s goals into routine ocean management.

Samson Vilvil Fare, director general of Vanuatu’s ministry of fisheries, oceans and maritime affairs, framed the zone as both a biodiversity reservoir and a climate mechanism, describing the transfer of carbon to deep water as a function whose protection is critical to the planet’s future. Eduardo Carrasquilla, administrator general of Panama’s aquatic resources authority, put his country’s position more bluntly, saying that without a healthy twilight zone the health of the entire ocean is at risk, and that Panama is committed to safeguarding every ocean layer from the surface to the deepest trenches.

Sivendra Michael, Fiji’s permanent secretary for environment and climate change, tied the commitment to the Pacific directly, saying that as an island state dependent on healthy marine ecosystems, Fiji sees protection of the twilight zone as bound up with the long-term health of the ocean and the well-being of Pacific communities.

What the challenge does not do

It is worth being clear about the instrument. The Mesopelagic Zone Conservation Challenge is voluntary. It sets no quota, creates no protected area, and carries no enforcement mechanism. Governments that join are committing to a management posture rather than to a binding limit, and two signatories is a coalition of two.

What it does offer is a marker planted before the fishery exists at scale, which is an unusual position for ocean conservation to be in. Most marine governance arrives after the extraction. Whether this one holds will be visible in specific places: in the decisions of regional fisheries management organizations, in the text of the next UN Sustainable Fisheries Resolution, and in how many more governments have added their names by the next Our Ocean Conference.

Full details of the initiative are available on the Mesopelagic Zone Conservation Challenge page, and the launch announcement is available in Ocean Conservancy’s press release of 18 June 2026. Statistics and quotations in this article are drawn from materials issued by Ocean Conservancy and its partners and are attributed to them throughout. They have not been independently verified by SEVENSEAS Media.

SEVENSEAS Media · Conservation Journalism for the Ocean