Mangroves Fight Climate Change, but Shrimp Farming Threatens Them
Climate•6 min read
How commercial fishing is destroying ecosystems around the world.
Words by Juliana Roth
While many socially and health-conscious consumers imagine fish consumption as an eco-friendly alternative to eating meat, the environmental damage caused by the fishing industry is inescapable. Overfishing ravages marine ecosystems by inciting a domino effect of species collapse. And commercial fishing pollutes oceans with discarded plastic gear, disturbing ocean floor sediments and killing vulnerable creatures.
By understanding the impacts of overfishing on marine habitats and human economies, we plainly see the need for sustainable solutions for our global reliance on overfishing. Divesting from industrial fishing operations offers the opportunity for a renewed relationship between the earth’s atmosphere and the sea.
Let’s take a look at what overfishing is, why it’s so destructive, and what can be done to stop it.
Just like eating too many handfuls of popcorn quickly leads to an empty bag, overfishing occurs when fish are harvested at a rate that is too fast for the natural regeneration of a population to occur. The current unsustainable speed of fish extraction creates a ripple effect throughout the ecosystem, including releasing CO2 into the atmosphere and destroying biodiverse coastal communities. It also leads to an inequitable financial and health burden placed on the most vulnerable workers and global communities.
The causes and effects of overfishing emerge from a complex web of industrial forces that have a strong interest in profiting off of the market for fish, which is composed of billions of consumers around the world. Even as scientists warn of the dangerous impact of the climate crisis on ocean health and the role of overfishing in intensifying its effect, the fishing industry continues to operate as a nearly impenetrable organization supported by government subsidies and illicit activity.
Most of the ocean is unprotected; there is little accountability for ensuring ethical and sustainable standards are upheld when fishing boats are out at sea. The fishing industry is a significant employer, with nearly 60 million workers. While you might assume such a flush industry would have strict regulations and control over their operations, most of the fisheries around the globe are overfished. Estimates suggest over $36 billion is generated annually in illegal fishing activity, with little intervention by governments who continue to subsidize the organizations responsible.
The fishing industry has historically been the recipient of government support that reduced the cost of operations in order to keep up with global demand for fish, which also supports the continued employment of many vulnerable workers. While this may seem like a noble cause, governments are essentially investing in an environmentally destructive industry and working against their purported claims to offer lasting solutions for the climate crisis.
Without careful analysis, and with continued pressure from fishing companies for more governmental support, the industry swelled to a size that is too large to be sustained. With nearly 80 percent of the world’s life making a home in the ocean, the continued subsidization of overfishing may eradicate marine biodiversity.
There are fishing communities in coastal regions that have sustainably run small-scale fishing operations that continue today. These operations are also threatened by the decimation of overfishing. Unlike corporate entities who enlist vessels out to sea to bring fish to global markets, small fishing communities are often providing an essential food resource to their home and neighbors. When a fish population is overharvested at the site of their business, one potential consequence may be that an entire community is forced to relocate.
The destruction of community-based fishing operations can create a huge cultural void, removing spiritual, historical and scientific knowledge unique to the practitioners. Social systems and identities formed around fishing practices are lost when overfishing eliminates their access to their cultural practices.
The majority of industrial fishing operations are located in the Mediterranean Sea. There are almost a 100,000 thousand fishing boats scouring the ocean for fish annually, with at least 75 percent of fish populations overfished (this increases to 93 percent once crossing into EU territory). As a result, the Mediterranean Sea’s population of fish has declined by a third. Bluefin Tuna, one of the most desirable species in the ocean, nearly went extinct due to the impacts of overfishing. A similar pattern was detected in the Pacific Ocean’s stock of Bluefin Tuna.
While some of the obvious harms of overfishing may be the mass killing of sentient beings or the degradation of ocean biodiversity, there are more subtle impacts of overfishing, like the erasure of cultural traditions around fishing practices.
There are also many long-term effects of overfishing that may take years for us to feel the impact of, but remain significant. These range from trophic cascade — when the removal of a predator (like sharks or cod) results in an imbalance in the food web — to reduced access to ocean recreation, impacting local tourism. The ocean is responsible for storing more than 50 times the amount of carbon dioxide (CO2) than the atmosphere, and by destroying such precious marine ecosystems, climate change and the acidification of oceans is exacerbated.
In order to target desired fish species, industrial fishing boats deploy a large net that is dragged along the ocean floor in search of creatures like crabs and shrimp. This invasion of an intricate ecosystem, an artwork created by centuries of complex biological processes, is often torn apart in seconds. Bottom dragging harms sea turtles and entangles marine mammals, like dolphins and whales, in their nets.
Practices like bottom dragging, dredging for clams and blast fishing usually result in the unintended capture of non-market species, like sea lions, dolphins, stingrays and chimeras. Overfishing resulting in extreme quantities of bycatch leads to sea creatures risking extinction.
Overfishing, along with aquaculture, is a serious threat to coral reefs. Coral reefs are crucial for marine ecosystems: they protect against floods for coastal communities, provide a home for many ocean creatures and create jobs for the ecotourism industry. Blast fishing, a common industrial fishing practice, breaks apart coral reefs. With the reduction of grazing fish who clean coral reefs of suffocating algal overgrowth, overfishing is a significant driver behind the destruction of coral reefs.
As new technologies continue to be introduced to further mine our oceans for fish, in particular when the fishing industry integrated radar and sonar, the increase in the rate and quantity of fish extracted from the ocean shook the entire ecosystem. Pollution from fishing gear and fuel (not to mention oil spills) also creates toxic environments for aquatic creatures. These changes to the ecosystem influence marine animals’ reproduction rates and access to essential resources.
As the composition of fish changes as a result of stocks of species being harvested through overfishing, regime changes — or the overtaking of one species by another — often occur, which then affects the chemical composition of the oceans. This can lead to an ineffectiveness of the ocean in sequestering CO2, or changes in salinity that may threaten the survival of other animal species.
Animals who live above the ocean’s surface are also affected. Seabirds are regularly captured and killed as a byproduct of overfishing. Commercial fisheries are also responsible for the capture and harm to nearly a quarter of a million sea turtles every year.
Fish play a crucial role in the chemical processes continuously at work under the ocean’s surface. Fish targeted by overfishing, like Baltic Cod, eat a smaller fish called sprat — who then eat an even smaller creature, zooplankton, who then eat algae. As cod disappear from their environments, sprat proliferate and result in less zooplankton to play their part in culling algae. This leads to algae blooms and eutrophication, or the depletion of oxygen from water, creating a “dead zone.” As oxygen levels reach dangerous lows, vital underwater plants and marine animals die off.
Just between the sunlit region of the ocean and the complex ecosystems below rests what might be the most significant area of the ocean for the removal of carbon dioxide (CO2) from the earth’s atmosphere, where CO2 is stored at the bottom of the ocean. This area is known as the twilight zone, home to most of the earth’s fish population. Were the twilight zone to continue to be disturbed and shifted, the atmosphere’s CO2 would rise by approximately 50 percent.
Ultimately, oceans are essential for carbon-sequestration and maintaining a stable atmospheric composition. Protecting marine environments is essential for slowing or possibly reversing the speed of the climate crisis. With a majority of the ocean stressed by overfishing, paired with the destruction and pollution of the marine ecosystems responsible for this important filtration, the loss of the ocean as a carbon hub is just one of the many long-term effects of overfishing.
While overfishing depletes fish populations, it is assumed that doing so is best for business. While there are short-term gains in hauling in large harvests of fish, overreliance on a species and ecosystem that is threatened creates instability and invites a serious risk for businesses. Once a species does collapse, the resource is no longer available to exploit, and businesses may need to shut down operations overnight, leaving mass unemployment in the wake.
Given that over half of the protein sourced from the ocean feeds populations in the most vulnerable countries, a collapse of the ocean ecosystem would have disproportionate effects on human life. Many communities also generate a significant percentage of their economy from tourism and international trade, which is threatened by climate change and overfishing’s impact on our oceans.
Just as there are opportunities to restore the ocean to a healthful and potent ecosystem that could more efficiently store CO2, there are opportunities to reverse or prevent the harm done by overfishing. The UN’s 2030 Agenda for Sustainable Development offers a blueprint for ending subsidies that lead to overfishing, but accountability is essential for seeing these policies bloom.
The 2021 documentary Seaspiracy was released to mixed reviews, causing debates between experts over the narrative presented in the film. Even so, the social impact of the film was strong, leading to increased public awareness of overfishing. Several other films have been made on the topic, and savvy consumers are increasingly aware of the cost of overfishing.
Attempts to regulate the entities that govern industrial fishing operations have historically been unsuccessful, but new research is being funded to introduce technologies that may monitor, track or prevent bycatch — and incentivize practices that cause less harm in marine environments. While the abolition of overfishing practices may be the most impactful, many scientists suggest there are avenues to regulate the industry.
The Good Food Institute compiled a list of nearly 200 seafood alternatives on the market. Common foods like watermelon, carrot, oyster mushroom and hearts of palm are also easily used to reimagine seafood-oriented recipes.
Government initiatives may continue to be introduced that could reorient labor employed by the fishing industry. Employees could use their skills in service of developing marine energy sources that harness tidal areas to create a crucial source of green energy. Resources may also be directed to replenish the cultural heritage of coastal communities that have been depleted due to overfishing.
Not only are fish harmed by the toxic runoff into water systems from industrial agriculture practices, but an extreme amount of suffering is caused for the fish who are bred, raised and killed through aquaculture, or fish farms. Marine animals — like oysters, salmon, yellowtail, trout and sablefish — are kept in cages in freshwater, marine and tank environments. While the practice was introduced as an efficient alternative to fishing on the open water, many risks are associated with this practice.
Similar to factory farm environments, aquaculture results in increased parasitic disease in fish, with the result an increase in resistance to antibiotics and antimicrobials that may lead to the proliferation of stronger diseases threatening both fish and human health. Farmed fish are also more likely to be disease carriers.
Farmed fish, who live in extremely crowded and stressful conditions, are also fed low-nutrient foods that they might not naturally eat in their native environments. The way the fish are raised results in a reversal or undermining of the potential nutritional benefits of fish for consumers.
Leading scientists continue to warn of a mass extinction of sea life. If current overfishing practices persist, research suggests we are almost certain to see an increase in species collapse in our oceans. Environmental advocates are urging a massive shift in our relationship with ocean life, and the fish who call the sea home.
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