Rise in Asian Tiger Shrimp sightings prompts scientific look at invasion
concerns
April 26, 2012
<http://www.noaanews.noaa.gov/stories2012/images/tigershrimp_10062011.jpg>
Asian tiger shrimp.
Asian tiger shrimp. (Credit / with permission from: Ryan Werner.)
The recent rise in sightings of non-native Asian tiger shrimp off the U.S.
Atlantic and Gulf of Mexico coasts has government scientists working to
determine the cause of the increase and the possible consequences for native
fish and seafood in those waters.
Researchers from the U.S. Geological Survey and National Oceanic and
Atmospheric Administration are working with state agencies from North
Carolina to Texas to look into how this transplanted species from
Indo-Pacific, Asian and Australian waters reached U.S. waters, and what the
increase in sightings means for native species.
"We can confirm there was nearly a tenfold jump in reports of Asian tiger
shrimp in 2011," explained Pam Fuller, the USGS biologist who runs the
agency's Nonindigenous Aquatic Species database. "And they are probably even
more prevalent than reports suggest, because the more fisherman and other
locals become accustomed to seeing them, the less likely they are to report
them."
NOAA scientists are launching a research effort to understand more about the
biology of these shrimp and how they may affect the ecology of native
fisheries and coastal ecosystems. As with all non-native species, there are
concerns over the potential for novel avenues of disease transmission and
competition with native shrimp stocks, especially given the high growth
rates and spawning rates compared with other species.
"The Asian tiger shrimp represents yet another potential marine invader
capable of altering fragile marine ecosystems," said NOAA marine ecologist
James Morris. "Our efforts will include assessments of the biology and
ecology of this non-native species and attempts to predict impacts to
economically and ecologically important species of the Atlantic and Gulf of
Mexico."
<http://www.noaanews.noaa.gov/stories2012/images/tigershrimp2.jpg> Asian
tiger shrimp.
Asian tiger shrimp.
High resolution
<http://www.noaanews.noaa.gov/stories2012/images/tigershrimp2.jpg> (Credit
/ with permission from: Bakenhaster at FWC.)
The cause of the rapid increase in sightings remains uncertain, Fuller
added. The non-native shrimp species may have escaped from aquaculture
facilities, although there are no longer any known Asian tiger shrimp farms
presently in operation in the United States. It may have been transported in
ballast water from ships or possibly arrived on ocean currents from wild
populations in the Caribbean or other locations.
Fuller's team at USGS has been tracking reports of Asian tiger shrimp since
they first came to the attention of marine scientists and resource managers
in 1988, when nearly 300 of them were collected off the coasts of South
Carolina, Georgia and Florida within three months. Scientists tracked the
cause back to an isolated incident that accidentally caused an estimated
2,000 animals to be released from an aquaculture facility operating at that
time in South Carolina.
It was not until 18 years later that reports of the non-native shrimp
resurfaced. In 2006, a commercial shrimp fisherman caught a single adult
male in Mississippi Sound near Dauphin Island, Ala. Within months,
additional specimens were noted in North Carolina's Pamlico Sound,
Louisiana's Vermilion Bay and other parts of Florida and the Carolinas. The
species was later reported off the coasts of Georgia, Mississippi and Texas
in 2008, 2009 and 2011, respectively.
Scientists have not yet officially deemed the Asian tiger shrimp
"established" in U.S. waters, and no one is certain what triggered the
recent round of sightings. With so many alternative theories about where
these shrimp are coming from and only a handful of juveniles reported, it is
hard for scientists to conclude whether they are breeding or simply being
carried in by currents.
<http://www.noaanews.noaa.gov/stories2012/images/tigershrimp3.jpg> Asian
tiger shrimp.
Asian tiger shrimp found in the Dominican Republic in 2006. (Credit / with
permission from: Cheryl Shew.)
To look for answers, USGS and NOAA scientists are examining shrimp collected
from the Gulf and Atlantic coasts to look for subtle differences in their
DNA, information that could offer valuable clues to their origins. This is
the first look at the genetics of wild caught Asian tiger shrimp populations
found in this part of the U.S., and may shed light on whether there are
multiple sources.
"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,
"If we find differences, the next step will be to fine-tune the analysis to
determine whether they are breeding here, have multiple populations, or are
carried in from outside areas."
Anyone who sees one or more shrimp suspected to be an Asian tiger shrimp is
asked to note the location and report the sighting to the USGS NAS database
at http://nas.er.usgs.gov/SightingReport.aspx.
If possible, freeze a specimen to help confirm the identity and contribute
to a tissue repository maintained by NOAA.
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