The rain and melting snow that runs off factory farms and animal feed croplands dumps more pollution load into our waterways - lakes, streams, and estuaries than all other human activities combined.
The cropland runoff contains soil particles, salts, organic debris, fertilizer, and pesticides. Soil particles smother fish eggs and bottom-dwelling organisms and block stream flow. Salts, primarily sodium and potassium chloride and sometimes referred to as “dissolved solids,” raise salinity of the water, rendering it unsuitable for certain organisms. Organic debris feeds microorganisms that deplete the water's oxygen supply and kill the fish. Fertilizers, mostly nitrates and phosphates, spur algal blooms that smother or actually attack aquatic organisms. Pesticides kill all living organisms.
Animals raised for food in the US produce 130 times the amount of waste that people do. The waste, containing vast amounts of nitrates, pathogens, and hormones, is stored in huge open cesspools, euphemistically dubbed by the meat industry as “lagoons.” Eventually, all this waste winds up in the nearest waterway, killing aquatic organisms directly or through formation of algal blooms. Some of the waste leaks into the ground, poisoning vital groundwater supplies.
Animal agriculture's insatiable demand for land to grow feed crops presses into service arid lands that require irrigation. Irrigation now accounts for more than 80 percent of all water available for use in the U.S. and leads to critical water shortages and bitter conflicts among water users, particularly in the Western states.
Waste from mid-Atlantic pig and poultry factory farms has destroyed fish populations along the Eastern seaboard and in the Gulf of Mexico. Every summer, a “dead zone” in the Gulf, sometimes as large as Massachusetts, becomes void of life due to hypoxia – severe depletion of oxygen.
Commercial fishing is wiping out the oceans’ biodiversity, as miles of long lines and trawling nets sweep up huge numbers of “non-target” aquatic organisms in their path. Shrimp trawlers discard as much as 85 percent of their catch, making shrimp arguably the most environmentally destructive fish flesh a person can consume.
Many marine animals are caught and killed for animal – not human – consumption. Fish meal is a primary source of protein in aquaculture and other types of factory farming.