Asian Tiger Shrimp on the East Coast: How Did They Get Here, and Do They Matter?

A shrimp that belongs in the Indo-Pacific is turning up along the southeast and Gulf coasts of the United States, and nobody is sure why. Asian tiger shrimp, native to Indo-Pacific, Asian and Australian waters, have been reported in small numbers in U.S. waters for years — and sightings have increased notably. Scientists are now trying to find out where they come from and whether they pose a threat.

An Asian tiger shrimp. Researchers are investigating the origin and possible impact of this invasive species. Credit: NOAA.

The questions

Researchers from the U.S. Geological Survey (USGS) and NOAA are working with state agencies from North Carolina to Texas to find out whether these shrimp carry disease, compete with native shrimp for food, or prey on native shrimp directly — and how they reached U.S. waters in the first place.

Where could they be coming from?

Scientists have not yet officially declared the species "established" in U.S. waters. Several routes are possible:

• Escape from aquaculture — though no Asian tiger shrimp farms are known to be operating in the U.S. now.
• Ballast water carried by ships.
• Ocean currents, bringing them from wild populations in the Caribbean, or even from Gambia in West Africa, where they are known to be established.

With so many possible sources, and only a handful of juveniles reported, scientists cannot yet say whether the shrimp are breeding here or simply arriving on the currents.

Reading their DNA

NOAA and USGS scientists are examining shrimp collected from the Gulf and Atlantic coasts for subtle differences in their DNA, which could reveal where they came from — and whether there is more than one source. It is the first look at the genetics of wild Asian tiger shrimp in this part of the U.S. NOAA is also studying the shrimp's biology and how it might affect native fisheries and coastal ecosystems. As with any non-native species, there are concerns about new routes for disease and competition with native shrimp, especially since this one grows and spawns faster than other species.

How you can help

If you see a shrimp you suspect is an Asian tiger shrimp, note the location and report the sighting to the USGS. If you can, freeze the specimen: it helps confirm the identification and adds to a tissue collection kept by NOAA scientists.

Sources

Based on "Why are scientists concerned about Asian tiger shrimp in East Coast waters?" from NOAA's National Ocean Service, a work of the United States government in the public domain.