Saving Seafood

Deep-sea mining risks disrupting the marine food web, study warns

November 6, 2025 — Drilling for minerals deep in the ocean could have immense consequences for the tiny animals at the core of the vast marine food web — and ultimately affect fisheries and the food we find on our plates, according to a new study.

Deep-sea mining means drilling the seafloor for “polymetallic nodules” loaded with critical minerals including copper, iron, zinc and more. While not yet commercialized, nations are pursuing deep-sea operations amid rising demand for these minerals in electric vehicles and other parts of the energy transition, as well as for technology and military use.

The researchers examined water and waste gathered from a deep-sea mining trial in 2022.

What the study discovered

University of Hawaii researchers studied an area of the Pacific Ocean called the “twilight zone,” about 650-5,000 feet (200-1,500 meters) below sea level. Their peer-reviewed findings, published Thursday in the Nature Communications scientific journal, say mining waste could affect anything from tiny shrimp smaller than .08 inches (2 millimeters) long to fish 2 inches (5 centimeters) long.

That’s because, after mining companies bring the mineral-rich nodules up to the surface, they have to release excess sea water, ocean floor dirt and sediment back into the ocean. That creates a murky plume of particles about the same size as the naturally occurring food particles normally eaten by the zooplankton that swim at that depth.

Read the full article at the Associated Press

Global conservation body takes first step to protect ocean’s twilight zone

October 23, 2025 — The mesopelagic zone is the chilly, dimly lit layer of ocean found 200-1,000 meters (660-3,300 feet) below the surface, which scientists say plays key roles in the marine food web and carbon cycle. On Oct. 15, delegates to the IUCN World Conservation Congress in Abu Dhabi adopted a motion to protect it. The motion calls for any activities that could harm the mesopelagic ecosystem, including fishing, geoengineering and deep-sea mining, to be approached with caution and guided by the best available science.

The World Conservation Congress is a global forum focused on nature and conservation that takes place every four years. The motion is one of the first steps toward safeguarding the mesopelagic zone globally, although it is focused more on limiting future damage rather than repairing any harm already inflicted on this part of the ocean.

The mesopelagic zone, sometimes called the “twilight zone,” is home to an immense biomass of fish — 600 million metric tons, according to one estimate. Species inhabiting this zone include lanternfish, pearlsides and squid, which are crucial food sources for predators like dolphins, tunas, marlins and sharks. Research suggests this vast zone also plays an essential role in regulating the climate by facilitating a process called the “biological pump” that moves carbon from the atmosphere into the deep ocean for long-term storage.

For now, a commercial mesopelagic fishing industry remains largely speculative. Launching it would require overcoming difficulties in locating, catching and processing mesopelagic fish. Still, there’s considerable enthusiasm for finding a way to make it work. While mesopelagic fish have been pursued for possible human consumption, there is a particular interest now in harvesting them for fertilizers or aquaculture feed.

Read the full article at Mongabay

Changes to Earth’s ‘twilight zone’ could cripple the Ocean’s future

March 15, 2021 –Welcome to the Twilight Zone It’s a real place — but under the sea.

The mesopelagic zone, also known as the “twilight zone,” is a mysterious region of the ocean between 200 and 1,000 meters in depth. It’s sandwiched between the sunlit surface and pitch-dark deep ocean.

A new study shines a light on its formation over geologic time scales, revealing the process is intimately linked with global temperature.

Currently, this is a boon to the creatures that live there. But, as anthropogenic climate change heats up the ocean, this finding suggests the twilight zone and its integral role in the carbon cycle may be negatively affected.

This is bad news not just for the animals that live there, but for people too — a twilight zone in balance is essential for keeping billions of tons of carbon out of our planet’s atmosphere.

Read the full story at Inverse

The Ocean’s Twilight Zone can Feed the World, but at what Cost?

March 25, 2016 — Life in the twilight zone constitutes a huge potential source of fishmeal and Omega 3 fatty acids needed to feed the world population. However, it exists in a kind of “no man’s water”, where there are no rules for fishing. Critical for assessing the resilience of the community and thus develop sustainable management strategies is a lack of understanding of the biological processes in the twilight zone making it impossible to accurately estimate the fishing pressure the stocks can sustain.

There are huge untapped resources of protein in the deep sea, but any potential exploitation should be done with caution, states the research community.

An international research group last year estimated that the so-called twilight zone (200 to 1,000 meters), maintains a community of fish, squid and crustaceans whose biomass far surpasses all the world’s current fisheries.

Furthermore, it is currently estimated that there are more than 1 million undescribed species in the twilight zone. According to the study, the twilight zone contains up to 90 percent of the world’s total fish biomass. There are so many creatures here that if estimates hold, it would be equivalent to 1.3 tons of fish biomass per person on earth, and that excludes squid and krill.

Read the full story at Ocean News and Technology