Vast and seemingly limitless, we traverse its edge on foot, its waves on ships and occasionally dive to its shallower depths. Our oceans cover 70% of the world’s surface and 99% of the world’s habitable space for life. However what resides within those endless blue waters for the most part remains out of sight and, sadly, too often out of mind.

The most recent scientific projections suggest that in around 30 years’ time—if current trends continue—marine fisheries will collapse. Essentially, this will be the point of no return, where the ocean’s fish will simply cease to exist in any meaningful way to us. As a result, over a billion people will be deprived access to their primary source of protein and a further three billion others one of their primary sources of protein. It also means hundreds of millions of jobs and livelihoods in jeopardy right across the entire planet.

In this article, we take a look at what’s happening to the world’s fish populations, how this will affect ecosystems both under the water and on land, what will happen if—and at this rate, when—the fish are gone.

A fishing trawler
Photo by Martin Dörsch

The tragic decline of global fish stocks

Globally, fish stocks are being over-exploited at an alarming and unprecedented rate. Each year we fish, dredge, trawl and sieve close to 100 million tonnes of marine life from the oceans to feed an ever-expanding and always-hungry human population.

A large proportion of these hauls produce significant amounts of bycatch, that is fish and other marine life caught up accidentally in the same nets. For every kilogram of shrimp that ends up on our supermarkets shelves, 4kg of bycatch has also been caught, then—more often than not—thrown back overboard, dead. It’s a modern and utterly ruthless approach to fishing, one where enterprises, companies and nations pursue short term agendas without full consideration of balancing the long term impact of their actions.

Currently only 10% of the world’s fish stocks are under exploited, with over two thirds being ranked as over exploited, depleted or recovering from depletion. After decades of over exploiting wild fish stocks, ships were having to venture further and further offshore for increasingly smaller hauls. As a result, intensive ocean-situated fish-farming has grown up, to the extent that it now accounts for around half of all fish used for human consumption.

But don’t be fooled into thinking that these farms have solved the fishing crisis. Aquacultures are most often located in the most vulnerable habitats—shallow coastal waters—and the waste produced by the pens can create harmful toxic algal blooms, degrading the surrounding environment.

Added to that, we tend to farm fish eating species high up the food chain, such as salmon and tuna. These species require a lot of fish to feed on, nourishment that often come from the normal methods of offshore fishing. So whilst the tuna or salmon on our plates might be farmed, the process is still causing havoc to our marine ecosystems by fishing just a little bit further down the food-chain, essentially sucking our oceans dry of smaller marine life.

But if the fish go, what happen next?

Photo by
Photo by

An ecological disaster already underway

The total loss of wild fish from the oceans would be catastrophic. If wild stocks of fish were to cease at a functional level we would be looking at mass extinctions in the marine environment. But the devastation would reach further than that, all the way up onto dry land.

As a species, we literally live and breathe the oceans; half of our oxygen comes from the ocean ecosystem, and the oxygen producers within it would quickly be the victim of the desertification process in much the same way as soil quality would suffer and become barren if nothing died and decomposed into it.

The death of fish would spell the end—or at least drastic upheaval— of many of our beloved natural land-based ecosystems. Take the salmon run in the North Eastern Pacific as an example. Nearly all salmon only make the journey back to freshwater once and once they’ve spawned, they die—their rotting carcasses adding much needed nutrients to otherwise nutrient poor alpine soils. As much as 80% of nitrogen in some soils comes from the decay of salmon carcasses.

On top of that, the salmon run bonanza forms the staple diet of a host of carnivores, including grizzly and black bears, wolves and a whole plethora of marine creatures. Without these pristine marine and terrestrial habitats functioning optimally together, it’s clear that every link in the chain would be on a very rocky road towards ecological disaster.

Wherever the location, the disappearance of fish would likely lead to a huge imbalance in the natural world. It is likely that vulnerable habitats such as coral reefs and kelp forests would be overrun first and only the most adaptable, resilient species will remain, in a far less dynamic and diverse ecosystem.

It could be that fish are displaced by more energy efficient jellyfish and the very nature of the marine ecosystem shifts, with these resilient ocean wanderers thriving in the absence of predators. Once this happens, it may be the point of no return for fish stocks, which will struggle to re-establish their once long-held dominance under the waves.

Photo by Brianna Fairhurst
Photo by Brianna Fairhurst

What this means for us

So what does the future look like? Well, there are some reasons for hope. First and most importantly, we are aware of the scale of the problem. Secondly, measures are coming in (albeit slowly) which are trying to address and reverse these declines.

More marine protected areas have been created in the last decade then in all the preceding years put together. There are some remarkable success stories both on a small scale such as Lundy Island and on a larger scale, such as the US led Pacific Remote Islands scheme. Customer led schemes are also taking hold and you can now choose to make a difference by eating locally caught fish, or from MSC certified fisheries.

Unfortunately however the response is slower than it currently needs to be. Ultimately, the final twist may be that the modern technologies, which developed so fast and left no species/stocks of fish safe from exploitation, may also be the saviour of the oceans. Fish farming, despite its current flaws, must be integrated more sustainably into our future fish consumption.

If we can find ways to farm fish in the least productive areas of the oceans, well away from vulnerable coastal waters and switch to farming less intensive fish-gobbling species like salmon, we may yet allow global fish stocks recover whilst still having enough fish to consume ourselves.

We all have a part to play in conserving the oceans. If we don’t we not only risk losing the heart and lungs of the earth, but we’ll all be on a jellyfish diet in the not too distant future too.