Deep seabed mining can devastate fish stocks by disrupting the seamounts they depend on
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Seabed mining could cause fish mortality, due to habitat loss and a decline in food sources. For example, phosphate extraction proposed in shallow water near Namibia is expected to impact fish populations through habitat and food source removal, with mining operations set to take place within migratory routes and spawning grounds.39
Similarly, within the deep sea, mineral deposits often occur in habitats that support important and diverse fish populations. For example, cobalt-rich crusts are often located on the flanks and summits of seamounts, underwater mountains that host a great abundance of species. These include slow-growing fish species such as orange roughy, grenadiers and redfish, the status of which – in the cases where data exist – is generally considered already overexploited or depleted by deep-sea fishing.40 In cases where seamounts have been severely destroyed by bottom trawling, there has been no sign of recovery of large bottom-dwelling fauna five years after trawling stopped, highlighting the vulnerability of these communities.41 Research suggests that it will take many decades or more for seamount communities to recover from such trawling.42 Greenpeace has been calling for a ban on deep-sea bottom trawling to stop the potentially irreversible impacts of this destructive fishing practice on sensitive deep-sea habitats and species. The impacts of mining in these areas would be even more devastating to the already threatened fragile ecosystems of the deep ocean.