Healthy coastal fisheries, which are crucial to coastal livelihoods and food security for billions of people worldwide, depend on good water quality.

Water quality is critical to fisheries health given its impact on abundance, location, and size of fish, all of which can affect costs, fishing effort, and revenue. Reef-associated fishes are particularly sensitive to changes in water quality, and impaired waters can lead to declines in abundance and shifts in species composition. Coastal low-income countries in the tropics, women, and Indigenous communities are the most reliant on healthy nearshore fisheries and coastal habitats globally. In particular, small-scale fishers are one of the most vulnerable sub-groups who rely on healthy fishery resources given their high dependence on fisheries for food and livelihoods. Coastal pollution must be managed to protect these vital nearshore fisheries and the livelihoods of all those who depend on them.

Wastewater is a key threat to coastal water quality globally.

“Wastewater” is a term that refers to used water and can encompass a variety of pollutants, including those originating from residential, commercial, and industrial uses as well as urban stormwater runoff. Sewage (wastewater from municipal sources) is a significant part of wastewater in many cases, and is a major driver of coastal ecosystem impacts. Sewage itself can contain nutrients, organic matter, bacteria, viruses, parasites, pharmaceuticals, endocrine disruptors, micro and macro plastics, industrial chemicals, sediments, and heavy metals. Sewage makes up the greatest volume of waste released into the marine and coastal environment, posing significant threats to nearshore fishery habitat and health. While wastewater treatment plants have become more efficient in removing many contaminants, they are not designed to filter everything.

Coastal fisheries and shellfish are exposed to an array of land-based pollutants through the discharge of wastewater and sewage into the ocean, including nutrients, endocrine disruptors, pathogens, heavy metals, and other toxins. Pollutants discharged into coastal waters can travel more than 100 miles from land and disperse into adjacent waters, which can affect entire fisheries and coral reefs. A recent global review revealed that sewage is polluting nearly every coral reef geography around the world.

Read the full article about how wastewater affects coastal fisheries at Our Shared Seas.