Female Asian tiger shrimp can grow to 12 inches in size and have voracious appetites, feeding on native shrimp, bivalves, crustaceans, and fish. It’s not clear exactly how they arrived in the area, but researchers suspect several pathways, including escape from aquaculture during tropical storms and hurricanes. They may also have been released from ballast water in ship, or simply migrated from wild populations in the Atlantic and Caribbean.
To learn more about the, government scientists are trying to determine the pathway of introduction, where they are established, and what this may mean for native fish and other organisms.
“We can confirm there was nearly a tenfold jump in reports of Asian tiger shrimp in 2011,” said Pam Fuller, the USGS biologist who runs the agency’s Nonindigenous Aquatic Species database and lead author of the 2014 article in Aquatic Invasions. “And they are probably even more prevalent than reports suggest, because the more fishermen and locals become accustomed to seeing them, the less likely they are to report them.”
Fuller’s team at USGS has been tracking reports of Asian tiger shrimp since they first came to the attention of marine scientists in 1988, when nearly 300 of them were collected off the coasts of South Carolina, Georgia, and Florida within 3 months. Scientists tracked them back to an aquaculture facility operating at that time in South Carolina that accidentally released an estimated 2,000 Asian tiger shrimp. It was not until 18 years later that reports of the non-native shrimp resurfaced.
To better understand where this resurgence came from, USGS and NOAA scientists are examining shrimp collected from the Gulf and Atlantic coasts to look for differences in their DNA—information that could offer valuable clues to their origins. This work might shed light on whether multiple sources are contributing to the new invasion.
“We’re going to start by searching for subtle differences in the DNA of Asian tiger shrimp found here—outside their native range—to see if we can learn more about how they got here,” said USGS geneticist Margaret Hunter, co-author of the article. “If we find differences, the next step will be to fine-tune the analysis to determine whether they have multiple populations, or are carried in from outside areas.”
Ongoing studies to examine the environmental DNA of Asian tiger shrimp in the southeast United States will help determine the extent of the invasion. Finding eDNA in the water will help researchers quickly locate new populations—especially populations of smaller individuals that are less likely to show up in commercial trawl nets. This is the same technology being used to track the spread of Asian carp in the Mississippi River and Great Lakes basins.
NOAA, USGS, and state scientists are also investigating the biology of these shrimp as it differs from native shrimp species. As with all non-native species, there are concerns over the potential for new avenues of disease transmission and competition with native shrimp stocks, especially given their high growth rates and spawning rates compared to other species.
“The Asian tiger shrimp represents yet another potential marine invader capable of altering fragile marine ecosystems,” said James Morris, marine ecologist at NOAA and co-author of the Aquatic Invasions article. “Our research efforts include assessments of the biology and ecology of this non-native species. We’re also working to predict impacts to economically and ecologically important species of the Atlantic and Gulf of Mexico.”
For more information on federal involvement in aquatic invasive species management, visit the Aquatic Nuisance Species Task Force website.