This is Part II of a three-part series on the global overfishing crisis and the sustainability of seafood.
Overfishing is a grave environmental concern. In a recent Care2 guest post series on overfishing in the U.S., Lee Crockett, the Director of Federal Fisheries Policy at the Pew Environment Group, explained that for decades now, humans have been catching more of certain species of fish than can be replaced by reproduction, causing populations of several popular seafood species to plummet. Crockett noted that, despite recent efforts to manage local fish populations more sustainably, nearly one fifth of fish species economically important to people in the U.S. are still being caught at unsustainable levels; some populations have dropped to less than 20% of numbers measured in the 1970s.
Fish, mollusk and crustacean species in seas around the world are suffering similarly from overfishing and habitat loss caused by unsustainable commercial fishing methods like bottom trawling, a wasteful fishing method that kills many more fish than can be sold to consumers, destroys coral reefs and drastically damages the sea floor.
Overfishing seriously threatens the supply of seafood species humans like to eat, but the potential effects of upsetting the balance of the ocean ecosystem go far beyond the dinner table. The ocean covers more than two-thirds of the Earth’s surface, and the condition of the marine environment affects life on land. Ocean life plays a key role in the Earth’s crucial carbon cycle. Just as trees and grasses absorb carbon dioxide on land, phytoplankton and marine plants in the water absorb carbon dioxide from the air; at least half of the oxygen we breathe comes from marine plant life, and marine plants absorb about half of the carbon dioxide currently produced by humanity’s industrial activities.
Already the world has seen signs that overfishing is drastically changing the ocean environment. The removal of so many top ocean predators, like sharks and tuna, from the seas has resulted in a population boom for jellyfish. In the past few years, jellyfish blooms have clogged harbors, sunk boats and even recently shut down several nuclear power plants. Overfishing has also been linked to an increase in algal blooms — overgrowths of algae that choke the sea’s surface and block out oxygen and sunlight, killing plants and fish below.
As in any ecosystem, in the ocean, the welfare of species is interconnected. When humans remove threads from the ocean food web by devastating certain marine species through overfishing, the entire ocean ecosystem is put at risk. We do not yet understand what the long-term consequences of overfishing may be for the planet as a whole, but the immediate consequences have already been severe.
The increased public interest in the sustainability of seafood is a positive development. But will a general public opinion shift in favor of eating less threatened, more sustainably harvested seafood species be enough to allow the ocean environment — and overfished seafood species — to begin to recover?
Consider this: in January of this year, the United Nations Food and Agriculture Organization reported that global per capita fish consumption reached a record high of 17 kilograms (about 37 pounds) of fish per person per year. According to the World Health Organization, global per capita fish consumption has been growing at the rate of 3.6% a year since 1961. And as individual seafood consumption has been on the rise, the number of people eating fish has also been growing: according to the U.S. Census Bureau, the world’s human population recently topped 6.9 billion.
In 1950, humans were harvesting about 20 million metric tons of fish each year. To supply the increasing, massive global demand for seafood in the 21st century, last year, global fisheries harvested more than 145 million metric tons of food from the sea: an increase of more than 700%.
Though consumers are beginning to be more conscious about picking more sustainably harvested seafood, the crux of the overfishing problem is that humans are eating too much seafood, period.
Read Part I of the Is Seafood Sustainable series. Part III coming soon.
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Photo of jellyfish at Monterey Bay Aquarium by Mila Zinkova, from Wikimedia Commons. Used under Creative Commons license.