Research identifies huge potential solution in deep-sea fishing but warns of environmental risks

The amount of biomass in the ocean’s so-called twilight zone is greater than previously thought

A Danish scientist is the lead author of research that suggests there could be a deep-sea answer to the global food shortage, but not without risk to biodiversity and the environment, reports.

Michael St John, a DTU professor at the National Institute of Aquatic Resources, along with a number of other researchers have published an article in the International Journal Frontiers in Marine Science exploring the potential of fishing in the ocean’s so-called twilight zone – the part of the ocean that ranges in depth from 200 to 1,000 metres.

Risks and rewards
“There is huge potential in the twilight zone. The indications are that there are resources of such a size that they alone could feed the whole of the world’s population,” St John told

But he emphasises that more study is needed before exploiting these resources, in order to avoid overfishing and potential damage to the sea’s ecosystem. There are also potentially catastrophic implications for climate change if deep-sea overfishing were to take place.

“It looks like 70 percent of the organic carbon reaching the deep ocean, an amount greater than that created by the burning of fossil fuels, is transported by this community. Thus, beyond their importance as food for other fish and humans, overexploiting this community could have serious impacts on climate change, limiting the amount of carbon dioxide the ocean can take up and thus increasing global warming.”

The future of fishmeal?
The article cites new research that points to there being a significantly greater quantity of organisms, or biomass, in this part of the sea than was previously thought. It is suggested that there may be as much as 10 billion tonnes – ten times more than past estimates. Some deep-sea fish are suitable for direct human consumption, while others can be used for feeding livestock and for aquaculture in the form of fishmeal.

“It’s incredible the amount of food we can produce with fishmeal. If we, as an academic exercise, imagine that we can fish five billion tonnes without overfishing stocks, that equates to food output of 1.25 billion tonnes,” St John said, pointing out that this community is rich in omega-3 fatty acids essential for human nutrition and growth.

Currently fishmeal production relies on fishing from coastal waters that already suffer from overfishing, so responsible deep-sea fishing could contribute to protecting biodiversity in these waters.