What Is Overfishing & How Does It Impact The Environment?

A scene of overfishing, with large nets catching unsuspecting wildlife.

Things work a little differently at sea – most life is found within animals and microorganisms, not plants.

The ocean may appear alien, but your everyday choices impact how well our planet’s marine ecosystems can adapt to climate change.

Eating seafood comes with a price of out of control overfishing, and our oceans are struggling to keep up.

But the seas of our world also show a remarkable ability to bounce back, as long as they’re given a chance to recover.

So what is overfishing, and how does it affect our oceans?

What is overfishing?

You may imagine a few different scenarios when someone mentions the overfishing crisis.

In general, overfishing refers to unsustainable fishing methods used to catch a wide variety of marine animals. The consequences of overfishing are quite severe, as many overfished species play key roles in some of the most important ecosystems on our planet.

A fleet of fishing vessels, ready to get some overfishing work done.
Image by William M. via Flickr

Not only are depleted fisheries becoming more common, taking so many fish out of the sea impacts all other species that thrive in these ecosystems. In some cases, areas on opposite ends of the ocean are impacted – as many oceanic species travel great distances to search for food or find a mate.

This may all be obvious to you. After all, what ecosystems have been spared from human greed? To illustrate just how insane the fishing industry is, let’s go over a few key examples of overfishing:

Examples of overfishing

It’s good to know how overfishing works before discussing issues that may arise from it, so we’ll go into the effects of overfishing a bit further down.

Much worse than your average person fishing along the shore, the scale in which fish are taken from the ocean is hard to wrap your mind around, so here are some easy to follow examples of overfishing:

Bottom-trawling. This is when huge weighted nets are dragged along or near the ocean floor, with the goal of catching fish and other animals like squid who live at the bottom of the sea. Around 25% of all fish are caught this way, at an estimated 20 million tons per year.

An illustration of otter-trawling, a form of bottom-trawling.

These animals are caught by the huge nets and may even be attracted to the noise and disturbed sediment that clouds the water, leading to a massive amount of them being swept up and eventually hauled aboard a fishing vessel.

Ghost nets. Fishing gear is often accidentally lost at sea, or intentionally dumped if it’s old or damaged. Sometimes this plastic waste ends up in oceanic landfills like the Great Pacific garbage patch, but you can find drifting nets all over the place.

A NOAA diver examining a large clump of ghost nets.
Image by NOAA via Flickr

Animals can easily mistake plastic trash for food or simply become caught in it while moving about, with an estimated 50 kilotons of fishing equipment accidentally lost each year – not including intentionally discarded gear.

Cyanide fishing and blast fishing. Reserved for only the most desperate of those looking for ways to profit from fishing, these two methods are particularly harmful to the ecosystems they take place in.

Cyanide fishing involves dumping or spraying sodium cyanide into ecosystems like coral reefs, and it results in the incapacitation of fish and other animals who are then easily collected for food or to be sold as pets.

Like its name implies, blast fishing is when fish are caught using explosives such as dynamite; powerful underwater shockwaves stun fish which then float to the surface – although a majority of fish are simply killed and sink to the ocean floor once their swim bladders erupt.

Accidental bycatch. A side effect of the methods mentioned above, fish and other animals that are caught, killed, or stunned by accident are called bycatch.

bycatch: non-commercial marine species caught while fishing

Contrary to popular belief, the environmental impacts of whaling pale in comparison to bycatch, in terms of whale population decline.

Baby sharks for sale in Somalia.

It’s impossible to control exactly which species are caught when fishing, so millions of your favorite sea animals are killed and tossed overboard once more valuable fish have been processed, such as:

  • Sea turtles
  • Whales and dolphins
  • Seals, sea cows, and sea otters
  • Sharks and rays

What are the causes of overfishing?

Each of the methods mentioned above have one thing in common: they’re indiscriminate. Meaning, the impacts of overfishing reach all life in our oceans – but this is kind of a vague concept if you aren’t a marine biologist.

So you may still be wondering: how and why is overfishing happening?

Here are the main causes:

Growing consumer demand for seafood. Wealthier nations like the US and Japan have traditionally consumed a lot of seafood – but emerging economies like Brazil, China, and other regions of Asia and Africa are starting to catch up.

Gutted, frozen tuna for sale in a seafood market.
Image by Stewart Butterfield via Flickr

When people start to make more money and elevate themselves to a higher standard of living, they tend to eat more seafood and meat in general; after all, corporations are always on the lookout for more mouths to feed.

Corporate sponsored industrial fishing operations. Around 60% of the ocean lies beyond enforcement by individual nations – with the high seas being a prime area of exploitation by industrial-level commercial overfishing.

100 corporations are responsible for around 35% of all fishing in the high seas, with the main states involved being China, South Korea, and the US.

Fishery lobbying, subsidies, and government involvement. Fish industry lobbyists are infamous for advocating for more generous subsidies, similar to how other kinds of animal industries work. These fishing subsidies artificially lower the cost of fishing – making it easier for overfishing to occur.

Inaction and indifference from governments around the globe also drives overfishing, with fleets from nations like China starting to spread beyond their home-waters in search of valuable fish stocks to satisfy consumer demand.

Because much of this occurs on the high seas, it can be nearly impossible to enforce, and illegal fishing operations are often ignored or even encouraged by governments themselves.

What are the effects of overfishing?

Fleets of fishing vessels are moving further and further out to sea, as profits from coastal fishing dwindle due to ecosystem collapse, one of the main climate tipping points we’re now facing.

With nearly 4 million fishing vessels in existence, aquatic ecosystems are never truly allowed to recover, unless located in protected marine zones.

Let’s take a look at some of the main environmental impacts of overfishing:

Overfishing leads to ecosystem destruction. The lower levels of our oceans aren’t just barren, sandy deserts – they’re incredibly diverse ecosystems teeming with life. Methods of fishing like bottom trawling and blast fishing physically destroy habitats like coral reefs, the most biodiverse ocean ecosystems.

A frenzy of sharks, a common victim of bycatch from fishing.
Image by Manoel Lemos via Flickr

The sodium cyanide used by some fishing communities also harms both fish and coral – in fact, both cyanide and blast fishing destroy more reef habitat than coral bleaching does in certain areas of the world like the Indo-Pacific.

Biodiversity loss means a less resilient ocean. The point for many employed in the industry is to catch high-value fish like tuna, or to capture beautiful tropical fish to be auctioned off in the illegal wildlife trade for aquariums. In doing so, countless other important species are killed.

A graph showing the decline in tuna stocks worldwide between 1960 and 2016.

All animals play a part within complicated oceanic food webs, and the staggering amount of biodiversity loss due to overfishing means that, overall, our oceans are less able to adapt to climate change.

Future generations are weaker and smaller. A decline in animal body size is one of the most recognizable signs of overfishing. Lobsters are a prime example, with lobsters of the past reaching over 25 lbs – much larger than what you’ll find at a supermarket today.

A captive lobster staring back into the camera.

Not only do animals shrink when species populations aren’t allowed to mature, but their general health and ability to fight off disease is also negatively impacted with less genetic diversity to go around.

It causes immense pain and suffering. There is a growing body of evidence that fish can feel pain, a relatively new concept previously dismissed by some experts and scientists, similar to recent developments in the study of animal culture!

Regardless of whether individual species feel pain the same way we do, the fact remains that sea-faring mammals like whales are also victims of overfishing – and it’s no secret these are some of the most intelligent and sensitive animals on earth.

Exhausting fish stocks doesn’t make financial sense. A perfect example of what happens when a lucrative species is overfished would be the Atlantic cod, although these cases are now common everywhere.

A net full of unsustainably harvested cod.
Image by Derek Keats via Flickr

This apex predator was hunted so ferociously by humans, that in 1992 a ban was placed on catching them – and their populations still haven’t recovered. Not only have cod not bounced back, but entire communities of people who previously relied on the Canadian and US cod industries were forced to find new sources of income.

Even ghost nets destroy profits, with a 2014 study estimating over $4 million in annual losses from ghost crab-traps along the coast of Louisiana, USA alone.

What are the solutions to overfishing?

Solutions do exist for overfishing, on a large and small scale, starting with changes in your lifestyle.

Removing fish and seafood from your diet. When it comes to your personal impact, it’s remarkably easy to distance yourself from marine-based products. Compared to something like reducing your plastic use, eliminating fish from your diet and life is simple.

Mud crabs for sale on ice at a supermarket.

Learning how to go vegan has never been easier with a wide variety of plant based meat brands found in most supermarkets – and even lab grown meat coming to market soon in places like the US, including seafood!

If you’re interested in doing more, you may even want to check out some of the marine environmental organizations working to make a real difference.

Marine protected areas and reserves. Areas in the ocean that are specifically set aside for the restoration and preservation of oceanic habitats and animal species have already proven to be a highly effective tool for conservationists.

A chart showing the amount of marine protected areas as of 2021.

No-take marine reserves in particular are seen as an excellent solution; the basic idea of these protected areas is to provide a safe area for species to live in, migrate to or from, and exist as they would in an ocean free from industrial fishing.

Strict management of fisheries through government regulations. Actions taken by individual nations like the US have had mild success in rebuilding fish stocks – but more comprehensive plans that include international cooperation are desperately needed.

Industrial fleets overfishing our oceans directly leads to fewer opportunities for small-scale fishers – which forces them to take drastic measures like blowing up coral reefs with explosives. Ironically, marine protected areas can make the financial situations of smaller fishing communities worse, regardless of the spill-over effect they can have on fish stocks.

Experts have recently begun calling for a global ban on high seas fishing, a logical train of thought when you consider the notion that harmful fishing subsidies increase CO2 emissions.

Aquaculture and seafood farming innovations. Wealthier nations are able to develop more sustainable and economical methods of farming fish, while also exploiting the cheap price of wild-caught fish from developing regions.

While farmed fish comes with its own issues, it also has around a 90% smaller carbon footprint than beef and a 50% reduction in land needed compared to poultry. Addressing these issues now, not decades from now, would enable more communities dependent on sea-based protein to reach their sustainability goals.

Final thoughts

The impact of overfishing extends beyond the seas; as socio-economic problems go hand-in-hand with the depletion of fisheries worldwide.

With so many fish being caught and so few solutions offered up, the recovery of our oceans will require cooperation amongst every nation and individual – our way of life depends on it.

Do you feel confident enough to stop eating seafood?

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