The study from Oregon State University says a quarter of teachers who use live organisms as teaching tools release the species into the wild when the classroom unit is finished, but only 10 per cent of them do it through a planned release program.
Principle investigator Sam Chan says teachers who don't follow a planned release program may accidentally be helping the spread of invasive species.
The survey found many of the most popular species used in classrooms, including crayfish, amphibians and various aquatic plants, have been identified as potentially invasive when not growing in their native climate.
Chan says the effects of releasing species outside of their original territory aren't always well-understood, and teachers should exercise caution.
He says live organisms are a valuable learning tool that teachers shouldn't hesitate to use, but says more thought needs to go into what happens once class is dismissed.
"We need to work through the whole chain and educate both the teachers and suppliers about the potential damages – both environmental and economic – that invasive species may trigger," Chan said in a statement.
Many of the nearly 2,000 teachers surveyed in the study were horrified when they learned of the problems they may have inadvertently caused, Chan said, adding the suppliers of the live organisms should shoulder some of the blame.
About 50 per cent of the species used in classrooms are provided by biological supply houses, with the remainder usually coming from pet stores and aquariums, Chan said.
Several suppliers consulted for the survey said it wasn't their job to educate the teachers, Chan said, adding the ones that did acknowledge the problem said they would be willing to look into ways to provide more local organisms for study.
We don't want to discourage the use of live organisms in teaching because they can provide focus, enhance student interest, and foster responsibility and care," Chan said. "But there are consequences to using them and both teachers and suppliers should consider what will become of these organisms when the classroom lessons are over."
The survey included teachers working in eight U.S. states, as well as those in Ontario and British Columbia. The findings were presented on Tuesday at the national meeting of the Ecological Society of America in Portland, Ore.