We were quite surprised the other night, to pull up a cast net with several good sized shrimp for dinner, and a shrimp-like creature that completely dwarfed them. We wondered at first glance if it was a florida spiny lobster, or a mantis shrimp, and took photos for identification before we released it back to the impoundment. Which would have been a good idea, if it had been a rare or endangered thing. In fact, it was an Asian tiger shrimp, Penaeus monodon. When we got home, we googled it, and found quite a bit of information about this non-native species. Ted was particularly chagrined to find one news report that mentioned them fetching a purchase price of $8.00 per shrimp!
Like most other shrimp, the jumbo prawns are cannibalistic, Morris says, and because of their size, they can gobble up many of their smaller Gulf cousins and their larvae. They also compete for the native shrimp’s food supply and spread through their environs, disrupting the eco-balance. Tiger shrimp spawn between 50,000 and 1 million eggs a cycle, he says. Testing will determine whether the tiger shrimp are in the early stages of a population boom.
In 1988, a batch of Asian tiger shrimp escaped from a research lab off South Carolina’s coast, leading to a surge in numbers, says Pam Fuller, an invasive species biologist with the USGS’ Southeast Ecological Science Center in Gainesville, Fla. The species has been rarely seen since.
Just to be sure, (and to find out what we should do if we caught another one), Reggie immediately emailed Lori, the island ecologist, and a friend at DNR. He sent the photos and information on to Dr. Peter Kingsley-Smith, a marine biologist at DNR, who replied almost immediately with this information.
In terms of status for this species, the past two years have shown an increase in numbers of tiger shrimp reported to us. We suspect that this may have been partly due to the mild winters helping tiger shrimp to overwinter, but there is still a lot that we do not know about the life history of this species outside of its native range. Tiger shrimp were first reported from coastal waters in South Carolina in 1988 but then did not reappear again until 2006. There has been considerable media coverage in recent years due to concerns as to the impacts that tiger shrimp might have on native shrimp populations, both from an ecological and economic perspective, but at this time we are still working on determining just how abundant tiger shrimp are, and we still do not know what impacts they are actually having in South Carolina waters.
Given that there are still many unanswered questions about this species in the southeastern United States, together with colleagues across the region, I am working to coordinate reports of this species and where possible collect specimens of tiger shrimp in order to conduct genetic analyses. These analyses will hopefully help us to determine the geographic source of these recent collections of tiger shrimp, but will also help us to answer questions about the relatedness of animals collected in different states from North Carolina to Texas.
In terms of specific actions that you can take, I am pleased that I have had the opportunity to communicate with you and let you know that I am interested in collecting information on tiger shrimp. Attached is a standardized data card that we have been distributing and this will show you the types of information that we would like to gather in association with tiger shrimp collections. I am still happy to work with you to complete this information. You can also help us by spreading the word that SCDNR is working on this species. We have a designated e-mail address that folks can use for reporting (firstname.lastname@example.org), or folks can contact me directly. We have also been putting up the attached poster to help spread the word that we would like information and specimens of this species.
Completed information is entered into the database managed by USGS and I work with them directly to report tiger shrimp from South Carolina. You can check out this website here: http://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=1209
In regards to the genetic analyses and specimens, if you do collect any more tiger shrimp, we ask that if you are willing to contribute to our genetics research, that you keep the tiger shrimp frozen until arrangements can be made to drop off the specimen here at the lab at Fort Johnson or to have it collected from the donors.
I am sure we will hear more from Lori about this in the coming days! In the meanwhile, Reggie entered his report after finding the latitude and longitude and translating it into minutes and seconds. In case you ever wanted to know, the coordinates for the crab dock are N 32.833043, W –79.725812.
Dr. Kingsley-Smith is in New Orleans presenting his research serving as our State Representative for South Carolina on the Gulf and South Atlantic Regional Panel on Invasive Species, and we look forward to learning more about this from him as well.