The phenomenon of stranded marine animals can be very surprising to scientists and local residents. There has been an incident of thousands of Urechis caupo or phallic and better known as penis fish, washed up on the shores of Drakes Beach, California, United States.
Urechis caupo is actually a species of marine spoon worm that spends most of its life burrowing in the soft sediments of the seafloor. These worms can live under the sand for up to 25 years, surviving by eating plankton, bacteria, and other small particles that fall into their bodies that have mucus traps.
Its unique shape resembling a penis does make it attractive. However, history records that one of the phenomena that appeared in December 2019, caused an uproar among local residents. At that time, there were thousands of penis fish with an average size of 25 cm scattered on the beach.
This photo was taken by a local resident named David Ford, and immediately went viral shortly after he posted it on his social media account.
"I don't know what happened. These animals were scattered for two miles," Ford said as reported by IFL Science.
"I walked for half an hour and they were scattered everywhere. There were seagulls lined up on the beach, along the way they ate so much (penis fish) that they were so full they could barely stand," he said.
Ford then tried to contact Bay Nature, an environmental agency and provided a special column to ask experts and scientists about a strange phenomenon.
This may just be the weirdest thing you've seen today!
Thousands of these marine worms, called fat innkeeper worms—or "penis fish"—washed up on Drake's Beach after a recent storm. But why? https://t.co/MwY6xkN3kb pic.twitter.com/vGMpSvGoAT
— Bay Nature magazine (@BayNature) December 11, 2019
Biologist Ivan Parr explains, Urechis has four species of penis fish. U. caupo is the only species found in North America, the other three being found in Asia, where they are eaten as a delicacy.
This worm makes a U-shaped burrow in the sand or mud, then secretes a slimy web that runs from the entrance to its mouth to suck in food.
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"Using peristaltic contractions to pump water through their burrows, penis fish suck plankton, bacteria and other debris into these nets," explains Parr.
"When conditions are like any vacuum, the net gets clogged, then the worm sucks everything back into its mouth, picks up the particles it wants to eat and dumps the rest into the tunnel," he said.
According to Parr, these animals scattered on the beach may be caused by damage to the environment they live in, or because of bad weather.
"We see a risk of building nests out of sand, strong storms especially during El Nio years, very capable of encircling the intertidal zone, breaking up sediment, and letting their contents, like this penis fish, wash up on the beach," he concluded.