They sound like a shrimp-lover’s dream. Nearly-foot-long creatures that are beautifully marked and absolutely delectable.
However, Asian tiger shrimp are proving a nightmare for researchers. The invasive specie is being found with increasing frequency in the Gulf of Mexico. Since they have never reached the Gulf previously, scientists and the shrimping industry are worried and are calling on the public for help.
“We’re definitely in unchartered waters,” said Mike Pursley, aquatic invasive species coordinator and field project manager at the Mississippi Department of Marine Resources (MDMR). “We don’t know what these creatures’ impact will have on the environment, especially our native shrimp.”
The Asian tiger shrimp, native to Southeast Asia, Australia and The Philippines, was first discovered in 2006 in U.S. waters, including the coasts of Alabama and Louisiana. Three years later, it was found in the Mississippi Sound near Pascagoula.
How they got here remains a mystery. Pursley and other sources say the creatures escaped from an aquaculture facility in the Caribbean, perhaps in 2005 due to Hurricane Katrina and/or Hurricane Rita. Others believe the shrimp were set loose in South Carolina back in the 1980s.
However they got here, since 2006 the number of Asian tiger shrimp sightings has increased. Last summer, the creatures were found in the Mississippi Sound near the East Biloxi Channel. After having no reports on Asian tiger shrimp catches in 2010, the MDMR has received reports of 13 discoveries in 2011. During that same time, Louisiana officials received reports of approximately 100 sightings.
A striking creature that gets its name from its distinctive black stripes, it can grow to more than 10 inches long, weigh better than a half-pound and can live up to three years.
They are also voracious predators, which has researchers concerned. Studies on the diet of Asian tiger shrimp in their native waters revealed more than 50 percent of its diet is other shrimp. Another important food source is crustacean larvae.
There is also concern that they could spread diseases to native shrimp that have no natural protection from bacteria, viruses and fungi carried by Asian tiger shrimp.
Thus, Asian tiger shrimp pose a potential threat not only to Mississippi shrimping industry, but also crabbers and other commercial fishermen.
The number of sightings in Mississippi waters trailed off after September. But, Pursley said that is typical. Asian tiger shrimp can only tolerate water down to 50 degrees Fahrenheit. They move off to warmer water in the fall, and disappear entirely in December.
Pursley said scientists are hopeful that this means Asian tiger shrimp will never get a firm foothold in the northern Gulf. But, uncertainty reigns.
“Everybody is cautiously optimistic,” he said. “But, we still have no idea what the potential impact might be. Only time will tell.”
Despite the uncertainty, the MDMR is trying to be aggressive in heading off a potential crisis to the shrimping industry that has been rocked recently by hurricanes, the economy, imports and the BP oil spill.
In October, the MDMR sent notices on Asian tiger shrimp to members of the shrimping industry. It is asking fishermen to report any catches of Asian tiger shrimp.
The agency is also asking the public to aid in the research. Those wanting to report Asian tiger shrimp can send an email to email@example.com or call (228) 374_5000.
While scientists attempt to get more information on Asian tiger shrimp, they are also cautiously watching the spread of two more invasive species – the lionfish and silver carp.
Lionfish are also voracious saltwater predators that lurk on reefs. With no natural predators, scientists are watching to see what damage they might cause to the ecology.
Lionfish have been discovered in Mobile Bay, in Louisiana waters and up the Eastern Seaboard.
Of a larger concern are silver carp. Another invasive specie from Asia, the freshwater fish can grow to more than 50 pounds, damage water bottoms when feeding and are a public threat — boat motors excite the fish, causing them to leap from the water and injure boaters.
The recent Mississippi River flood had researchers worried that the silver carp would spread quickly. Currently, there is no evidence that the flood further spread the silver carp here in Mississippi, threatening such rivers as the Pearl and Wolf. Still, state officials are staying vigilant.
The MDMR has released a flyer titled “Have You Seen This Fish?” It asks individuals to report all sightings with location to firstname.lastname@example.org.
There are also other invasive Asian species threatening South Mississippi from the land — the Chinese tallow tree and cogongrass.
The Chinese tallow tree, or popcorn tree, is deciduous, and can reach 60 feet in height. It is a rapidly growing tree that colonizes by root sprouts and seeds that are spread by wind, water and birds. The tree invades riverbanks and upland sites and is shade and flood tolerant.
Yet another Asian invader is cogongrass. As reported by the Mississippi Business Journal last July, cogongrass poses a threat to the environment by squeezing out native species, and is a threat to the economy because it crowds out pine tree seedlings.
Additionally, cogongrass is a threat to public safety and property. The weed burns like a fuel fire, and can consume 50 acres in less than an hour on a windless day.