Student Summan Mirza pets the tail of a flounder on an earlier night hike at Beaufort. [Katie Vo]
Student Summan Mirza pets the tail of a flounder on an earlier night hike at Beaufort. [Katie Vo]

Mucking Around

At the Marine Lab, students look at what lurks beneath the water after dark.
August 7, 2012

Dan Rittschof sweeps his scuba light across a sliver of the Neuse River. It’s 11:30 p.m., and he and his students are taking one last look across the water to see if any interesting creatures appear.

“I see an alligator eye,” Rittschof says, standing ankle-deep in water. Two students beside him ask him where, a twinge of anxiety in their voices. Rittschof points his light straight out into the water, where it catches a reflection about thirty yards from shore. An orb about the size of a quarter gleams red, lingering just long enough for the students to get a good look before it sinks beneath the surface.

“Okay, back to shore,” Rittschof says, his voice steady. “Let’s grab a few more sea nettles and then head home.”

It’s not the first time Rittschof and his students have seen an alligator on one of his nighttime excursions around the Duke Marine Lab in Beaufort, North Carolina. And alligators aren’t the only wild animals they’ve encountered. “In the twenty-eight years that I’ve been coming out at night, I see something new every couple of times,” he says. Rittschof takes his students on night hikes to teach them about the ecology and marine life of the waterways around Beaufort. Many of the area’s wild residents don’t appear during the day, when humans are out. “They’re too easily eaten,” he says.

But the hikes are also a kind of indoctrination. “Walking at night makes you alert,” Rittschof says. “You’re not secure in your surroundings or your footing, which gives you just the edge to observe what is in front of you a bit more clearly.”

Rittschof’s hikes usually take students either to the banks of the Neuse or to a small island a short canoe-paddle away from the marine lab. On this rare occasion, he takes students to both destinations. The first adventure, to the island, begins at 8:30 p.m., just as the sun is setting. Rittschof and four women taking his “Biochemistry of Marine Animals” course equip themselves with life vests, paddles, fishing nets, a few five-gallon buckets, and scuba lights duct-taped to wooden poles, and then head to the lab’s dock. They pile into two canoes and set off, thankful the winds from the approaching tropical storm Beryl have not yet reached North Carolina.

Lights from Beaufort, the nearby Coast Guard station, and a half moon put the strip of land into silhouette. Rittschof jumps out of his canoe as its bow lodges into the gooey muck near the shore. Students plunk into the mud and help carry the boat high enough on the island so that it won’t be swept away by the rising tide. By now, the students in the second canoe have arrived. The women splash into the mud. “I’m stuck,” one cries, and another gives her a hand to help pull her feet free. They drag their canoe up the beach, prompting Rittschof to remind them gently to lift it.

Creatures of the night

Creatures of the night: Under the glare of a scuba light, a female blue crab glides away from Rittschof. [Katie Vo]

With nets and lights in hand, the group paces across the island. Suddenly Rittschof stops. He switches on his scuba light and casts the beam a few dozen feet in front of him. Thousands, maybe millions, of inch wide fiddler crabs scurry along the shore, their asymmetrical claws and tiny legs waving rapidly as they feel around for food. “Let’s start getting some into the bucket,” Rittschof says. Students begin picking up crabs by hand, a few at a time. “Ooh, they’re pinching me!” one student exclaims, shaking her hand. “Stop!”

Rittschof uses a small fishing net to dump a scoopful of sand and crabs into the bucket. “That should be enough,” he says. Rittschof—whom most students call “Dr. Dan”—moves nimbly through the dark. The students stop at a tidal pool, where they see a sea anemone with its fleshy tentacles extended, feeling around for an evening snack. Its Medusa-like head is visible for a moment before retreating back into its tube-like foot.

As they continue along the shoreline, the students chatter, joking about the size of their toes. “Hanging out with twenty-yearolds keeps me young,” Rittschof mutters with a laugh. He may have even smiled briefly, though a crunching underfoot quickly shifts his attention. “Let’s walk a little higher so we don’t crush the crabs,” he says.

Rounding one side of the island, Rittschof splashes knee-deep into the water. When the students gather around him, he turns on his scuba light and dunks it underwater. The students follow suit, fanning out in a line along the shore. They spot blue crabs—females popping with eggs and even a mating pair. Rittschof jokes that the two crustaceans probably aren’t amused by the audience, and so the group leaves them to their cavorting.

The group isn’t looking for anything in particular. Like Annie Dillard in Pilgrim at Tinker Creek, they’re out just to discover. When a student talks about catching a flounder with her bare hands, a flounder hunt ensues. The search goes empty, but Rittschof does bare-hand a hogchoker, a three-inch, flat fish whose scales feel smooth when rubbed in one direction and rough in the opposite. “Hogchokers are my favorite,” Rittschof says, explaining that their slippery-yet-rough scales choke a predator when it tries to swallow them.

"Did you see that alligator's eye sink underwater?"

The hogchoker is barely back in the water when a student yells, “Squid! Squid! Squid!” Everyone freezes except Dr. Dan. He skitters over to where the student is pointing and maneuvers two nets back and forth like an ambidextrous chef, eventually pulling up the gelatinous creature to the light. He reaches into the net and tries to lay the squid out in his hand, but the critter is furious, its translucent skin turning spotty. The squid wriggles and squirts a stream of water from his bowels. “He’s trying to bite me,” Rittschof says, calmly dropping the cephalopod back into the net. They watch it squirm in the water for a few moments before letting it go.

Two students stay on for the second leg of the tour, which begins after a thirty-minute drive along a gravel road to the edge of the Neuse. They emerge into a swarm of mosquitoes, breaking the eerie nighttime calm with the occasional slap of palm against skin. Again, Rittschof shows no hesitation walking into the dark waters, and the students follow. Their lights reveal the long, red tendrils of sea nettles, a kind of jellyfish, jiggling through the water.

After a few minutes of walking downriver, the water gets deeper, and Rittschof suggests heading back to shallower depths. His experience tells him that deep water could mean alligators or sharks. But he hasn’t lost a student on a nighttime hike yet. Moving closer to the shore, they press on to a spot where a cold-water stream feeds into the river. Tall grasses surround alleys of muck, perfect alligator hiding spots. But they also are hoping to capture video of dancing fish, thousands of six-inch mullet that are known to leap and twirl into the air when scuba lights shine above them. Tonight only a few juveniles flip and jive. It’s a bit of a letdown, but “that’s how these walks go. You never know what you’re going to see, and no two experiences are the same,” Rittschof says.

Disappointed, the crew heads upriver again, toward the car. And that’s when they see the alligator’s eye. Rittschof seems surprised. He leads the students back to the riverbank and dumps a few more sea nettles into a bucket. It’s not until he gets the bucket, lights, nets, the two students, and himself safely back in the car that he asks, “Did you see that alligator’s eye sink underwater?” That was spooky, he says. “Glad I wasn’t here by myself. At night, things like that creep me out.”

Yeager is a science writer for Duke’s Office of News and Communications.