While most commercial fishing occurs at sea, the seafood on our plates does not often start in the big blue ocean – it starts where the rivers meet the sea, says an article published in forbes.
Special Places
The special places where freshwater rivers mix with the salty ocean are known as estuaries. Even if you have never heard of an estuary, you probably know of a couple; Virginia’s Chesapeake Bay, Washington’s Puget Sound, Florida’s Tampa Bay, and California’s San Francisco Bay are all estuaries.
Twenty-two of the world’s 32 largest cities are located on estuaries. In the U.S. alone forty-three percent of the population lives by an estuary!
What are Estuaries
Estuaries are natural safe-havens for many animals. With the help of surrounding marshes, estuaries offer protection from the unabashed, energetic ocean making them natural nurseries for many marine animals. They support seagrass – an aquatic plant (not a seaweed!) that grows in shallow, protected saltwater and provides refuge for other marine life to forage, hide, and thrive.
Life-supporting nutrients
Estuaries are also are teeming with life-supporting nutrients. River water carries land-based nutrients into the estuary, and salt-water animals take advantage. The special features of estuaries make them an essential component of the seafood industry accounting for up to 75% of commercially-caught seafood.
Crabs, oysters, shrimp, and many fish are just some of the animals that rely on estuaries for part of their lifetime.
Dungeness crabs
Dungeness crabs, which support a multi-million-dollar fishing industry, are born in the open-ocean as larvae but relocate to estuaries once they are juveniles. Inside these river-mouths, the juvenile crabs can scavenge for food and hide from predators – including other Dungeness crabs. At about 4-years old, Dungeness crabs are large enough to catch and eat.
Similarly, oysters and mussels first start their lives as free-swimming larvae. They move with the ocean currents, on the hunt for microscopic algal cells known as phytoplankton. It’s not until these shellfish grow up to be ‘spat’ that they start to produce shells and settle on the estuary’s sandy floor.
Oyster spat settles on the shells of other adult oysters, which leads to the creation of oyster reefs.
Million-Dollar Industry
In the Chesapeake Bay, the largest estuary in the United States, oysters must be at least 3 inches long to harvest, which takes the oysters three to five years to achieve. Nonetheless, wild-caught oysters support a $34 million-dollar industry in the Chesapeake Bay.
Fish, too, rely on estuaries for their survival while growing up. From salmon to trout to flounder, many fish we eat live in estuaries before moving into deeper water as adults.
So if you enjoy seafood on your plate from time-to-time, thank an estuary.
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Source: Forbes
