A study from an international team of ecologists and economists have predicted that by 2048 we could see completely fishless oceans. The cause: disappearance of species due to overfishing, pollution, habitat loss and climate change. The study was conducted in an attempt to understand what this loss of ocean species might mean for the world.
The Oceans and Us
50% to 85% of all the oxygen we breathe comes from “marine phytoplankton” in simpler terms, tiny ocean plants that photosynthesise and produce oxygen. This means that the oceans are the main lungs of our planet. Oceans also play a major part in regulating the temperature and climate of the earth after all 70% of the earth’s surface is covered with water. With oceans playing such a big role in how the world goes round it’s natural to wonder what this study proves in terms of the impact our current seafood production practices have on Biodiversity.
Bottom trawling is one of the two main methods used to capture wild fish, this method of fishing involves dragging heavy weighted nets across the sea floor in order to capture fish, this method is popular in the fishing industry as it can catch large amounts of fish in one go. However there are consequences to this practise…when dragging these weighted nets across the ocean beds everything and anything in the way of the nets get swept up too. This leads to masses of by-catch and also severely damages the ocean bed — distributing other aquatic life and their habitats.
Boris Worm who led the study, an assistant professor of marine conservation biology at Dalhousie University in Halifax, Canada states in the report — “Biodiversity is a finite resource, we are going to end up with nothing left if nothing changes…”
Oxygen Deficient Dead Zones
Aside from our current fishing methods causing critical biodiversity loss, the study found another problem has arisen known as oxygen deficient dead zones or areas where hypoxia has taken place. Dead zones are areas of large bodies of water that do not have enough oxygen to support marine life. Dead zones occur all around the world, but primarily near areas with heavy agricultural and industrial activity causing nutrient pollution — excess nutrients run off land or are piped as wastewater into rivers and coastal waters. The increase in chemical nutrients in the water, leads to excessive blooms of algae that deplete underwater oxygen levels.
Most sea creatures cannot survive in these zones and if current trends continue dead zones will lead to mass extinction among many forms of aquatic life. Ocean dead zones with zero oxygen have quadrupled in size since 1950, while the number of severe deprivation of oxygen sites near coasts have multiplied tenfold.
Worm says “It’s been a slow- motion disaster. It’s silent and invisible. People don’t imagine this, it hasn’t captured our imagination.”
Long Line Fishing
Long line fishing is another common practice the fish industry uses, this method involves trailing large lines of nets through the oceans with thousands of baited hooks attached to the nets. Similar to the bottom trolling method the lines are indiscriminate which means that by-catch is also a major problem. An estimated 50 million sharks are caught as a result of by-catch annually as well as every year around 650,000 whales, dolphins, sea lions and turtles are killed because of seafood production, this equates to more than one every minute. Our methods of fish farming are currently responsible for the mass killings of millions upon millions of other forms of aquatic life every year.
Worm talked about the effects of by-catch stating that tight-knit connections between ocean life and their habitats may explain why species diversity affects ecosystems so closely.
He used the analogy of the relationship to a house of cards in describing ocean communities — “Remove one species or habitat type within an ecosystem and the whole community completely falls apart”
Perhaps what’s more worrying is the consistent response the study found, the study examined the effects of species loss on 32 marine environments at local, regional and global scales in numerous different ecosystems.
Everywhere they examined they got the same results; the greater the loss of diversity, the greater impact on ecosystem services.
Worm says he was “shocked and distirbed” by how consistent these trends are — “beyond anything we suspected.”
What damage has already been done?
As a result of the seafood industry practices, somewhere between 10 to 40 percent of all fish caught are by-catch, furthermore there has been a 60% decline in the population of sharks in our oceans. This is continuing to have a huge impact on the biodiversity of our oceans and has already caused many species of aquatic life to be fished to the brink extinction as there continues to be an overwhelming demand for seafood.
Another study from The United Nations FAO stated that 87% of the world fisheries are either over exploited or fully exploited with nearly ⅓ of edible fish having declined by 90%.
Researcher from the study Beaumont stated “If biodiversity continues to decline, the marine environment will not be able to sustain our way of life. Indeed it may not be able to sustain our lives at all”.
Can we reverse this?
Regardless of the extent of Worm’s findings he believes that we can recover our oceans, “This can be done. It’s not beyond our reach at all.” he says.
Marine biologist from Oregon State University, Jane Lubchenco commended the study for giving hope to those invested that ecosystems can recover if immediate action is taken.
“The first conclusion about the downward spiral [of biodiversity] suggests that the rate of implementation of those recovery tools needs to be sped up quite significantly” she says. However “just making recommendations doesn’t make things happen, unfortunately”.
Ultimately the diversity of our oceans are the key to its survival — waters with the greatest biodiversity are the healthiest. The study strongly suggests that we need urgent management of ecosystems that sets aside some zones completely to free from any human activity, while opening others to certain uses, such as aquatic research and fishing. Worm also states that this needs to happen quickly, there is no time to waste.
The ultimate goal of this project would be to sustain marine ecosystems carefully, enough so we can still operate fishing practices in certain zones but not at the cost of all of our ocean life remaining at risk extinction.