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RIC employee scopes out shrimp invasion

A Rhode Island College library technician made a surprising discovery last summer when he identified an aquatic intruder to Rhode Island’s waters – a creature whose presence could upset the ecological balance of the environment and even affect the economy.

Ray Hartenstine
Ray Hartenstine works in the Adams Library by day and is a research volunteer for several Rhode Island watersheds by night. While he normally specializes in freshwater invertebrates, he took initiative in this case to investigate saltwater areas to uncover the shrimp Palaemon macrodactylus.

The invader shrimp has the nasty habit of wiping out local shrimp populations in the other areas where it has been discovered. This, in turn, could affect the fragile ecological balance of the environments into which it has trespassed. Because other, larger aquatic creatures such as fish and eels rely on shrimp for sustenance, an all-encompassing swap-out of shrimp species could spell a severe change in the population’s dining habits. Should certain fish lose their primary food source, their numbers will either dwindle or they will relocate.

And, as if Palaemon macrodactylus’s presence wasn’t jarring enough, the shrimp is also known to carry a fungus that could cause disease among the local fish population. Because a large part of Rhode Island’s economy is based on fish and seafood, a decline in the numbers of fish could mean a dip in seafood sales overall.

Having heard reports that the shrimp had been found in the nearby Mystic River, Hartenstine acted on an educated hunch and decided to search the Providence River for the invasion. Both the Mystic and Providence rivers are brackish, estuarine environments – a perfect match for macrodactylus’s typical nesting areas, he explained. The proximity of the Mystic River also tipped the volunteer off.

Last August, Hartenstine’s efforts came to fruition. He used a simple umbrella net and a few chicken bones to bait the creatures. “After sitting there from seven o’clock at night to about midnight, I was able to catch what I was looking for,” Hartenstine said.

Thanks to the invasive shrimp’s relatively enormous size (in comparison to the local shrimp), they were easy to spot among the trawled creatures.

Hartenstine brought the samples of the shrimp he trawled to Jim Carlton, a professor of marine sciences at Williams College, who verified the intruder’s identity. Carlton is widely recognized as the world’s leading expert on aquatic invasive species.


Palaemon macrodactylus shrimp
Researchers can only speculate as to how macrodactylus was able to end up in Rhode Island’s waters, but there is one primary theory. John Torgan of R.I.’s Save The Bay organization suggests that the creatures hitched a ride on international shipping boats. “We think it (the shrimp) came in, in ballast water in ships,” he said.

Ballast water is water taken in by ships to balance them as they cross the oceans. Several sea creatures have the opportunity to hitch a ride, and when the water is dumped into the port of the boat’s destination, the transfer of species is a very realistic possibility.

The Rhode Island Coastal Resources Management Council (CRMC), an organization that manages aquatic invaders such as this, was grateful for Hartenstine’s efforts.

“On behalf of the CRMC, I’d like to thank Mr. Hartenstine for his diligence in discovering this new invasive species,” said CRMC Chairman Michael M. Tikoian. “Having dedicated volunteers like Mr. Hartenstine will ensure the effectiveness of our monitoring program.”

Hartenstine was surprisingly humble about his discovery. “This is something that didn’t require a lot of specialized equipment or technical know-how,” he said. “This was easy to do. Anybody could’ve done it. I just had the forethought to do so. I was lucky I was the first.”

The aftermath of the shrimp’s discovery has placed Hartenstine in the limelight of the marine community, but not overwhelmingly so. “I’ve had a few people contact me, interested in learning or having me do other things," he said. "All in all, it’s a flash in the pan. But I don’t do these things for the so-called glory. I do this stuff because I like to do it.”