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NC - Lose the seagrass and lose the fisheries

Marine and estuary plant life on which North Carolina’s fish species depend are vulnerable to warming and rising seas, scientists say.

A small net dipped into a patch of grass submerged in shin-deep water near the edge of a salt marsh on the central North Carolina coast.

Retired National Oceanic and Atmospheric Administration scientist Jud Kenworthy of Beaufort lifted the net to reveal a colorfully striped juvenile pinfish, no bigger than a pinkie, among the strands of green and brown vegetation.

Pinfish are among dozens of fish species residing in estuaries for part of their lives, grazing on underwater grasses. Eventually, schools of the small fish, distinguished by a sharp dorsal fin, will spawn offshore in large groups and be hunted by predators: groupers, snappers and dolphins.

Their journey ends when hooked by a recreational angler from a pier or captured by a commercial fishing vessel to be used as bait for a bigger catch.

But the pinfish depends on the rich estuarine habitat that flourishes along the North Carolina coast — an ecosystem that relies heavily on a meadow of grass covered by 12 inches of salt water where land and sea merge. The threat of climate change to those seemingly mundane patches — which are seldom above water — is a threat to the entire oceanic ecosystem.

Indeed, the insidious impact of climate change on North Carolina’s coastal fisheries — the species in the water and the people who catch them, study them, sell them and eat them for dinner — may lie in murky meadows of submerged aquatic vegetation, or SAV.

The unnoticed foundation

Kenworthy anchored his small vessel in Back Sound, between Shackleford Banks and the mainland of Carteret County. The east end of the sound is framed by two barrier islands, separated by a narrow inlet, which meet at a 90-degree angle at Cape Lookout. The junction forms what looks like the apex of a tensioned slingshot, ready to blast its ammunition inland.  

“North Carolina is at this unique biogeographic boundary,” said Kenworthy, a thunderhead bulging over the Atlantic Ocean behind him. “There are probably only two or three places in the world like this, where major ocean current systems overlap and collide.”

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