New research suggests significant impacts of deep-sea mining on Pacific tuna fisheries

Matěj Moleš
Matěj Moleš

A recent study suggests climate change is pushing eastern Pacific tuna fisheries closer to the emerging deep-sea mining industry in the Pacific. Predictive climate models indicate significant shifts in tuna distribution in the near future. In the expansive Clarion-Clipperton Zone (CCZ) of the Pacific — home to deep-sea mining exploration contracts covering 1.1 million square km — the biomass of bigeye, skipjack, and yellowfin tuna populations is projected to increase by 10-31%, posing complex and uncertain challenges at the intersection of mining, fish populations, and climate change.

If the three deep-sea mineral companies currently holding exploration licenses in the Cook Islands move toward commercial mining, conflicts with fisheries are likely to arise, with several potential negative impacts:

  1. Mining operations will generate plumes from stirring up sediment at the seafloor and by discharging water and materials from the surface mining vessel. These plumes could disrupt filter-feeding apparatuses, like gills, as well as visibility for communication, increasing stress hormone levels.

  2. Noise generated during mining activities could also affect tuna and their prey, altering feeding and reproductive migrations and potentially reducing catch rates. Furthermore, metal concentrations in the discharge plume may lead to toxin accumulation in tuna, disrupting the seafood supply chain.

Alarmingly, current research on the environmental impacts of deep-sea mining is primarily conducted by mining companies, raising concerns about the quality and accessibility of the data. Recognizing the significant scientific gaps regarding the effects of deep-sea mining on fisheries and marine ecosystems, 21 countries already called for a halt to deep-sea mining.

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Matěj Moleš

Campaign Manager

Born in the snowy Czech mountains, Matěj’s thirst for knowledge brought him to sunny South Africa. Equipped with political savvy, oceanic wisdom, and a surfboard, catch him in the water hanging ten/on for dear life, smiling either way.

Cape Town, South Africa

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