Crabs and fish could start acting weird during the eclipse

Ghost crab
Ghost crab

Ghost crabs may emerge from the beaches, fish could start feeding more and acting strangely—all during next Monday’s total solar eclipse, scientists say.

For those traveling to the Grand Strand to witness this rare event, there’s a good chance you will see some out-of-the-ordinary activity in the ocean and on the beaches, according to experts.

If you’ll be fishing on Monday, you might have a better chance of reeling in some fish.

“Fishermen have reported changes in how the fish hit their lines during an eclipse,” said Rob Young, a marine science professor at Coastal Carolina University. Marine predators that hunt mainly at dawn and dusk start to bite more, he added.

Eric Rosch, another CCU marine science professor, agrees. He said a lot of marine predators go on feeding binges during low-light periods.

“I would love to be on the water fishing during an eclipse,” Rosch said.

Rosch believes anything active during low-light periods will probably show an increase in activity, including sharks.

“Sharks and game fish are things I would expect to get excited with lower-light levels,” he said.

Some unusual things may happen on the beach too.

“Being a crab biologist, I wouldn't be surprised to see a lot of large ghost crabs coming out on the beaches,” Rosch said.

Ghost crabs are straw-colored or grayish-white crabs, measuring about 2 inches across the back at maturity, according to the South Carolina Department of Natural Resources. They are common on outer beaches and on more protected harbor beaches near coastal inlets along S.C.’s coast.

“There are thousands of ghost crabs on our beaches, especially in less developed areas,” Rosch added. “We rarely find them downtown near the boardwalk, but there are strong populations in the state parks and Waties Island. If you've ever noticed a decent sized hole, quarter-sized or larger on the beach, chances are that it is a ghost crab.”

Waties Island is an undeveloped island near North Myrtle Beach used primarily for research purposes.

Rosch said the ghost crabs are primarily nocturnal, so you typically don’t see them during the day and many of them cover up their burrows.

“During the eclipse, I would expect them to start to emerge and roam and hunt until the sun comes back out,” he said.

Fish that live in reef communities have also showed abnormal behavior during total solar eclipses.

According to Young, the reef reef includes a group of many species that are mainly active during the day, called diurnal, and a separate group that are nocturnal.

“During a full eclipse, diurnal species have been observed to stop feeding and seek shelter and some nocturnal species start to emerge and become active,” Young said.

“When the sun goes down, one group seeks shelter for the night and the other group comes out,” he added. “This can occur briefly during an eclipse, especially the diurnal species seeking shelter.”

Plankton and small fish may also react to the eclipse.

“Any species in the ocean whose behavior is sensitive to light cycles may be fooled briefly by an eclipse,” according to Young. “Plankton and small fish move up and down in the water column depending on light cycles.”

Rosch added zooplankton will probably go into “nighttime mode” during the eclipse.

“Zooplankton usually go deeper during the day to avoid being eaten, so I would bet they would start migrating toward the surface, ‘nighttime mode,’ during the eclipse.”

In addition to the marine life being affected by the eclipse, land animals also do some strange things.

“During a total solar eclipse birds will stop chirping, crickets will begin their evening chirps, and cattle are known to return from pasture thinking that it’s the onset of night,” said Louis Rubbo, an astronomy professor at CCU.

Young said day-active orb-weaving spiders start to take down their webs during an eclipse, then rebuild them again when the sun comes back out.

Michaela Broyles: 843-626-0281, @MichaelaBroyles