Child and Adult Knowledge of North American Invasive Crayfish Species Pacifastacus leniusculus

Abstract

The distribution of North American invasive crayfish species Pacifastacus leniusculus has rapidly extended to lakes and rivers in Hokkaido, Japan. In 2006, P. leniusculus was designated as a regulated living organism under the Invasive Alien Species Act by the Ministry of Environment of Japan because it may have negative effects on native animals, including the endangered Japanese native crayfish Cambaroides japonicus. The establishment of P. leniuculus is considered to be the result of introduction by humans, including children. Thus, children also need to be educated about the impacts of P. leniusculus, as well as other invasive species, on native ecosystems. However, our present school education has an inadequate educational curriculum on invasive species. In this study, we made a questionnaire survey of elementary students in the fourth grade (n=141) to clarify knowledge by children of P. leniusculus. We also made a questionnaire survey of a wide range of residents (n=100; 70% adults) living in an area around a river in Obihiro City, Hokkaido, where P. leniuculus is established, to compare the knowledge of P. leniusculus between children and adults. Both children and adults had an inadequate knowledge of P. leniusculus and often confused P. leniusculus with the native C. japonicus and the invasive crayfish Procambarus clarkii. The results showed that many children and adults release P. leniusculus into unspecific rivers, lakes or marshes after they stop rearing P. leniusculus in their homes, suggesting that such releasing of P. leniusculus by children and adults causes the continuing new establishments of P. leniusculus in Hokkaido. Thus, we need to educate children, as well as adults, using accurate knowledge of invasive crayfish in biological and environmental education in schools and communities.