There’s an unseen foreign invasion going on in the Gulf of Mexico. Its stealth and speed are matched only by the uncertainty it has created among scientists and the people who make their living from the Gulf’s waters, warn scientists with the Texas Sea Grant College Program, based at Texas A&M University.
Lionfish and black tiger shrimp are only two of more than 40 species of non-indigenous sea life known to be spreading through the Gulf of Mexico from their native waters, but they are seen by many resource experts as the most threatening. Lionfish have been a growing problem in the South Atlantic Ocean and Caribbean area for most of a decade, but black tiger shrimp are a relatively new phenomenon. A few were captured in the Gulf of Mexico each year beginning in 2006, but the numbers rose significantly in 2011.
This year, more than 60 of the shrimp were brought by shrimp boats to one dock alone in Louisiana and the first captures off Texas’ coast were reported to the federal government. Three black tiger shrimp were caught in Aransas Bay, one was caught in Sabine Lake and one was caught in federal waters about 70 miles offshore from Freeport.
Lionfish are strikingly colored, brightly striped and venomous fish that can quickly populate an area and decrease native populations through either eating them or chasing them away. Black tigers are the largest species of shrimp in the world. Females are slightly larger than males and can grow to an average of about a foot in length and weigh close to three-fourths of a pound. Black tiger shrimp eat the same types of food as native shrimp species, but as they grow they also eat their smaller cousins.
Invasive species often find themselves in foreign ecosystems devoid of the natural predators and diseases that kept their populations under control in their native ranges. Free of these challenges that plague native wildlife, invasive species can turn all of their energy toward feeding and reproducing, Sea Grant officials explain. In some cases, the manner in which invasive species live can physically damage their adopted ecosystems to the point where it becomes poor habitat for native species.
“We just don’t know what the long-term impacts are going to be,” says Gary Graham, Texas Sea Grant’s fisheries specialist. “I don’t know whether these shrimp will establish themselves in the Gulf of Mexico or play themselves out, but I think they could become a more serious problem than anyone originally thought.”
“The biggest concern we have is what are the ecological impacts of these invasive species?” says Dr. James Morris, an ecologist with the National Oceanic and Atmospheric Administration (NOAA) who has been working with lionfish for about 10 years and is now taking the lead in NOAA’s efforts to study black tiger shrimp. “When you look across the history of invasive species, there have been some very extreme impacts that have resulted from invasions.”
For more of this story, go to the Sea Grant website.