Google EarthĪs a result, estuaries are highly productive. In the United States, 50-75% of the total “marine” fish harvest comes from estuaries. But most importantly, from the perspective of productive fisheries, they are where rivers dump their nutrients into the oceans.Ĭhesapeake Bay, the largest estuary in the United States, illustrating how estuaries are where river. Estuaries encompass a range of habitats distinct to the swirling dance of water and sediments that occurs when river blends with ocean-mudflats, marshes and, in tropical latitudes, mangrove forests-that are crucial for fish spawning and rearing.
What are estuaries? They are defined as the places where rivers meet the ocean, where freshwater and saltwater mix. Nutrients drive productivity, and nutrients are in scarce supply across much of the open ocean – but they are abundant in estuaries. Rivers also exert a strong influence on a significant portion of ocean fish harvests. now represents about half of all fish consumed globally (Statista) Lower left: rivers and other freshwater systems produce about 19% of global capture fisheries (WWF) Lower right: Adding capture fisheries and aquaculture, freshwater systems produce more than 40% of all fish consumed globally. Upper left: 68% of global aquaculture production is from freshwater (WWF) Upper right: aquaculture. Freshwater fisheries also employ at least 60 million people worldwide, more than half of them women. Because about half of all fish consumed come from aquaculture, that means that rivers and other freshwater systems produce more than 40% of all fish consumed globally each year, equivalent to about 7% of all animal protein.įor hundreds of millions of people in rural regions of the world, freshwater fish are an essential source of protein – and also a range of micronutrients.
Because of this, experts believe the harvest from freshwater systems could be more than 60% higher than what is officially reported, or approximately 19% of global capture fisheries.įurther, most aquaculture production (68%) is from freshwater species-dominated by carp, catfish and tilapia-raised in water from lakes and rivers.
Many freshwater fisheries are quite small scale with catches that are never recorded or sold within formal markets. However, they almost certainly haul in a lot more than 12 million tons. In fact, floodplains and wetlands are among the most diverse and productive habitat types on Earth, and the most productive freshwater fisheries come from rivers connected to extensive floodplains, such as the Amazon, Irrawaddy, and Mekong.įrom these rivers, lakes, and associated floodplains, fishers haul in approximately 12 million tons of fish per year, about 13% of all capture fisheries around the world, and enough to feed nearly 200 million people. Within these shallow habitats, the sun can drive food webs to support diverse species of plants and animals. That tiny volume is spread across various types of freshwater habitats, and while the oceans are incredibly deep-and so, by volume, most ocean water is dark and unproductive-most freshwater habitats are relatively shallow. The first question you may ask is: how can so many fish come from such a tiny (globally speaking) volume of water?
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