Winds, Tides and Weather

Bill Trandum

Bill Trandum

The ‘Ghosts’ of Key Pen Beaches

You stroll across a Key Peninsula beach, the tide is out but is not particularly low. Suddenly your foot plunges nearly 2 feet deep through the sandy surface into a sort of quicksand. Maybe you plunge all the way to your thigh. When you try to pull your foot out, your boot or shoe on that foot comes off and your other foot sinks and it feels like you’ll never escape. If you have a walking stick, you push it down, hoping to find a purchase for it, but it sinks a good 4 feet and you never feel it bottom out.

Finally you pull the stick out and lay it crosswise across your path. You bend to it and place both hands on it, shoulder width apart, and struggle like crazy to get either foot free. Eventually, with both shoes or boots buried, you practically lay yourself down on the stick and try to worm your legs back to the surface.

Now, you try to stand up to find that both shoeless feet keep slipping back through the liquified sand. Finally, unless someone with solid footing helps pull you out, you lie on your back and squirm your way to solid gravelly beach.

Maybe you go back later with a square of plywood to stand on and a shovel to try to recover your boots or shoes, which may be as much as 4 feet deep, and every shovel full of sandy slurry you try to dig simply slides back into the quicksand pit.

So what’s going on? Is it an evil result of some nearby aquaculture project? An unseen outflow of subterranean water from a creek or lagoon?

Most likely none of the above. Burrowing sand shrimp, also known as ghost shrimp or mud shrimp, seeking to dine on plankton, have populated sandy intertidal zones all over the world. Their tunnel systems are reminiscent of anthills and may extend as deep as 16 feet. They can live as long as 20 years and grow as large as 4 inches long. Except for the “sinky” sand pits they create, they (and their poop) are harmless to humans.

Surface-cultivated oyster beds often sink out of sight, never to be seen again. Oyster farmers have tried and trued to defeat ghost or mud shrimp, even employing insecticides to kill them.

Environmental concerns have stopped that practice, at least here in America. So far no one has come up with a safe way to get rid of them.

They are sometimes used by fishermen as bait and are a significant food source for gray whales.

And these critters have been around a long time. Fossilized ghost shrimp and tunnels date back to the Pleistocene epoch. And apparently they favor beaches fed by a supply of fresh water.These little shrimps love west coast U.S. beaches from Alaska to San Diego as well as Australian and New Zealand intertidal zones. So no, the soupy soft beach condition is not caused by some man-made intervention.

Bill Trandum, a resident of Vaughn, is a retired U.S. Navy captain and a self-described student if all things winds, waves and waters. He has sailed, fished, crabbed and shrimped pacific coastal waters from Alaska to California.