Is Climate Change Threatening the World’s Fisheries

Image by Revolve Solar
As if overfishing didn’t already exert enough extreme pressure on the supply of seafood, warming ocean temperatures are diminishing the ability for global fisheries to repopulate

January 12, 2016 —You know that whole climate change thing you’ve been herring so much about? Well, in addition to increased natural disasters, melting glaciers, and rising sea levels, the climate crisis is dolphin-itely threatening the world’s seafood supply. We apologize in advance for the fish puns, but you should know that if we don’t make them, salmon else will.

Let minnow if you think of another good fish pun we can use in future articles, and I’ll be sure to mullet over with the editor.

It might be time to say “Au Revoir” to your caviar.

But in all seriousness, the seafood we are used to eating might not be available much longer if the climate crisis continues to wreak havoc on the world’s fisheries. As if overfishing didn’t already exert enough extreme pressure on the supply of seafood, warming ocean temperatures are diminishing the ability for global fisheries to repopulate.

According to a recent study published in the Proceedings of the National Academy of Sciences, there is a clear decline in the number of younger fish. After looking at data from more than 260 commercial fish stocks around the globe, researchers believe the declining population is tied to a decrease in the amount of available phytoplankton (microalgae).

“This, as far as we know, is the first global-scale study that documents the actual productivity of fish stocks is in decline,” said Gregory L. Britten, a doctoral student at the University of California, Irvine, and the study’s lead author. “We think it is a lack of food availability for these small fish. When fish are young, their primary food is phytoplankton and microscopic animals. If they don’t find food in a matter of days, they can die.”

The World’s Major Fisheries

fish stocks
Percent Change in the World’s Fish Stocks (Red circles=decreasing populations, green=increasing populations)

The North Atlantic is one region that has been hit particularly hard by a decline in the amount of microalgae though overfishing complicates matters by reducing the number of larger fish capable of laying eggs. Around the South Pacific, near Australia and South America, the problem of a lack of phytoplankton was more pronounced and correlated with a floundering fish supply.

Are Warming Oceans Krilling the Fish?

Marine ecosystems (like all ecosystems) are extremely sensitive to changes in temperature. While it’s true climate phenomena like El Niño cause ocean waters to warm more than usual, many climate scientists believe the global temperature increase is causing El Niño temperatures to last longer. In turn this is adversely affecting marine life.

Researcher Rebecca Asch, for instance, studied the same 43 varieties of fish in coastal Southern California for 57 years. She found that the fish gradually changed their spawning season due to the warming waters. When the immature fish hatched, there was not enough food available and many died off.

Considering more than three billion people worldwide include fish as a major source of protein in the diet, this poses a huge problem for global sustainability.


But it goes beyond simply not having enough food to eat. The entire fishing economy is threatened as you can see from these few facts from the World Wildlife Fund:

  • Twelve percent of the world’s population depends on fisheries to make a living.
  • There are 18.9 million fish farmers on the planet.
  • Ninety percent of these fisheries are small-scale and from developing countries.
  • Roughly half of them are run by women.
  • Coastal fisheries account for 40 percent of the wild seafood caught in the world.

Avoiding Turtle Disaster

Scientists say that a ‘business as usual’ scenario for policy making won’t be enough to halt the impact that climate change is having on the world’s fisheries. In order to counteract a diminishing supply, Governments around the world cannot simply focus on overfishing as the sole issue. They must acknowledge the threat climate change poses to our oceans.

The problem comes down to a warming planet. We won’t be able to stem the rising temperatures immediately, but reducing carbon emissions is the best long-term solution. Rising ocean temperatures, especially along the world’s coastal areas, threaten the sustainability of fishing. Only through reduced emissions, combined with the sensible harvesting of seafood, can we prevent disaster. To ignore the issue would be a major missed-hake.

| Revolve Solar