Key Threats
KEY THREATS TO THE DEEP SEA
A range of human activities pose a risk to life in, and the health of, the deep sea. Key among these are deep-sea fishing, the possible start of deep-sea mining, and a range of geoengineering plans proposed as solutions to the climate crisis that could impact deep ocean areas
The principal drivers of threats to the deep sea are the same across all these activities: governments prioritizing exploitation over ocean protection, failure to honor commitments, lack of transparency, and inadequately regulated exploitation and extraction. Many of these problems are rooted in the fundamental flaws of the current global economic model, where short-term gains for the powerful few override longer-term benefits for the many. Both individually and collectively, these failures are allowing and enabling the degradation of vulnerable deep-sea ecosystems.
Deep-sea mining to source metals including nickel, manganese, cobalt and copper could result in one of the largest impacts of any industrial activity on our planet. There is widespread concern about the potential threats to the ecosystems and habitats of the deep if mining is allowed to go ahead. Increasingly urgent questions are being asked about whether deep-sea mining is necessary, desirable, or economically viable.
The threat posed to deep-sea biodiversity by destructive fishing is comparable to the devastation of tropical rainforests. Vulnerable deep-sea ecosystems stand no chance against the ruthlessly effective weighted nets dragged by bottom trawlers, and they can also be impacted by longline fisheries. Thousands of species are at risk, most of them still unknown to science and many not existing anywhere else on Earth.
As coastal and open-water fisheries become ever more depleted and overexploited, industrial fishing fleets have turned to deep-sea species. Many use highly destructive bottom trawling techniques.
To capture a handful of “target” species, deep-sea bottom trawl fishing vessels drag huge nets equipped with steel plates and heavy rollers across the seabed, pulverizing sea life in their path.
These vessels fish on seamounts, in deep-sea canyons, and on the rough seafloor – areas that were once avoided for fear of damaging nets. They plow through biologically rich and diverse ecosystems, crushing corals, sponges, marine life and habitats as they go.
Many species of unwanted fish are caught as “bycatch” and thrown back dead into the ocean. In a matter of a few weeks, bottom trawl fishing can destroy what took nature many thousands of years to create.
Specifically, the damage caused by deep-sea bottom trawl fisheries has led to pervasive concern about the conservation of fragile seabed habitats. The 2015 United Nations World Ocean Assessment found that bottom trawling has caused widespread, long-term destruction to deep-sea environments globally, stating that it may take “centuries to millennia” to recover from the impacts. It also reported that the “vast majority of deep-water fisheries have been carried out unsustainably … This has led to the serial depletion of dozens of stocks.”
Deep-sea bottom trawling is an especially indiscriminate fishing method, with high bycatch and discard rates compared to other types of fishing gear. Many species, including some that are highly endangered, are accidentally caught and thrown back into the sea dead.
As the search for solutions to the climate crisis intensifies, governments, industry and scientists are looking increasingly to the ocean. As a result, several “ocean-based climate interventions” are currently being developed that propose deploying geoengineering manipulations and technologies to remove and store CO2, manage solar radiation, or generate renewable energy.
