Our oceans are home to complex and interconnected ecosystems, and even the tiniest forms of life play an essential role. For example, did you know that phytoplankton produce around half of the world’s oxygen?

It’s critical that we fight animal agriculture and aquaculture’s destructive impacts on the sea this World Oceans Day (June 8) and beyond.

Read on to learn four ways that factory farming—of terrestrial and aquatic animals alike—is devastating our oceans and what you can do about it.

Factory farms produce enormous waste, 940 billion pounds of manure annually in the U.S. alone. Much of this waste is stored in manure lagoons, and when these seep or overflow, excessive nutrients like nitrogen and phosphorus can end up in our waterways. This can lead to what’s known as a “dead zone,” areas of the ocean where no life remains. 

Aquaculture (the farming of marine life) is intensifying worldwide, as the industry accounts for around half of the world’s seafood production. Some fish farms are in the ocean, where animals are severely crowded into open nets and pens—and from these marine factory farms, pollution can seep into surrounding waters and impact wild fish. This includes animal waste, parasites, pathogens, antibiotics that can contribute to treatment-resistant illnesses, and more.

Around half of the world’s wild-caught fish are used in fishmeal or oil, mainly feeding farmed animals—including carnivorous farmed fish, like salmon, one of the world’s most commonly farmed aquatic species. It takes an estimated 440 wild-caught fish to raise just one farmed salmon.

Animal agriculture is one of the biggest drivers of climate change and greenhouse gas emissions. As our oceans absorb more carbon dioxide from the atmosphere, their waters become more acidic. This puts many species at risk and can even dissolve the shells or exoskeletons of clams, lobsters, crabs, and other sea life. Plus, acidification is threatening our world’s coral reefs, which offer vital habitat to around 25 percent of marine life.