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UNCP scientists peer into the black waters of the Lumber River

July 9, 2009

Over the years, odes to the Lumber River have been sung by poets, outdoorsmen and Native Americans before them.


Under the microscope

But it took a pair of scientists from The University of North Carolina at Pembroke to get a close look at one of the little known creatures lurking beneath the black water.

“Shrimp in the Lumber River?” said Andrew McMillan, a UNCP senior Environmental Science major “I’d never heard of it before.”

“I’ve never seen a one until we started this project,” said Dr. Patricia Sellers, an environmental science professor in UNCP’s Biology Department.

Two years ago, McMillan was taking the course “Freshwater Ecosystems and Watershed Management” from Dr. Sellers, when they hauled in their first freshwater shrimp, he said.

“Later, when she said she wanted to look into it a little further, I volunteered,” he said. “We didn’t know a lot about freshwater shrimp and wanted to learn more.”

Collecting trips on the river sounded like fun to an avid hunter and Eagle Scout from the Wakulla community of Robeson County.

When a scientific inquiry is launched, investigators never know what they’ll find until they start down the road, or river in this case. Finding the first shrimp was a start.


Andrew McMillan and Dr. Patricia Sellers work the river bank off Deep Branch Road

The first hauls produced not one shrimp but two separate species – Palae- monetes paludosus and Palae- monetes kadiakensis, both commonly known as grass shrimp (and sometimes referred to as glass shrimp). More secrets began to unfold.

McMillan sent lab photos to Dr. Horton Hobbs, a noted expert on freshwater shrimp at Wittenberg University. Dr. Hobbs verified the separate species.

“Dr. Hobbs noted that it was ‘certainly unusual’ to find the co-existence of two separate species,” Dr. Sellers said.

With little prior research to guide them, the project launched an inquiry into the frequency of this co-habitation of species.

“We did have access to surveys from 1980s by the (state) Department of Environment and Natural Resources’ Division of Water Quality that found one of these species,” Dr. Sellers said. “We have the state’s unpublished data on shrimp from their periodic benthic invertebrate monitoring.”

There were more surprises in store as the investigation moved forward, she said.

“This morning, we thought we found a new species, but we won’t know until it is verified,” Dr. Sellers said on March 16. “It is unlikely.”

Armed with a seine and sweep nets, McMillan and Dr. Sellers set out last winter to learn more about shrimp stocks, distribution and habitat at different locations on the river.

“We didn’t know where we would find them,” McMillan said. “We considered factors like salinity, water depth and current.


Every dip of the net teamed with life

“We found shrimp like low flows and calm water and grassy banks,” he said.

Back in the lab, McMillan photo- graphed and examined the shrimp which appear very similar to their much larger salt water cousins. Dr. Sellers said there is more to learn.

“When the state sweeps, they say that 10 or more shrimp is an abundant supply,” she said. “We’ve had difficulty at some sites and the water has been very high at times.”

Rivers and shrimp are relatively new to Dr. Sellers, who studied Canadian lakes for many years.

“I am more familiar with microbial life in water more than organisms the size of shrimp,” she said. “This project started with an idea in a classroom.”

Dr. Sellers and McMillan collected samples all semester, and they often found themselves up to their necks in the work.

“The water is cold,” McMillan said with a grin. “We went on the day it snowed in January.”

On a warm afternoon in March, the search took them to a location off the Deep Branch Road. The poets are right about the Lumber River; even in winter, its beauty is magical.

In waders, McMillan and Dr. Sellers searched in a grassy area along the bank with no luck at first. The tan grass teams with life - fish, crayfish, spiders, dragonfly larvae and tiny crustaceans wiggled and squirmed in their catch.


One the banks, they sorted the catch of the day

“These beds are interesting,” Dr. Sellers notes. “You get something from every group of organisms.”

They spilled the catch on the bank, and a crayfish headed off one way and a spider tried to crawl up McMillan’s hand. He was having fun.

“There’s a lot of cool stuff,” he said. “If you find the usual suspects, you usually find shrimp.

“I think I’ve got one,” McMillan said, as he sortied through mud and grass. “It’s like fishing; sometimes you get lucky.”

“Yea,” Dr. Sellers said. “They look almost silver and usually they jump.”

The total haul at the first site was five tiny shrimp that went back to the lab in the Oxendine Science Building for further examination under a microscope.

The project wass part of an independent study course and resulted in a poster presentation at the Undergraduate Research and Creativing Forum last spring.

McMillan graduated in May and aspires to continue his studies.

“I am applying to ecology grad schools in New Mexico and Arkansas,” he said. “If that doesn’t work out, I’d like to work with the forestry service.”

Until graduation, McMillan continued collecting and making poster presentations.

“I  titled the project, ‘Shrimp in the Lumber River,’” he said. “I think that’s enough to surprise people.”


McMillan holds the prize, a tiny grass shrimp