Didymo Control: Increasing the Effectiveness of Decontamination Strategies and Reducing Spread

ABSTRACT

Nuisance algal blooms formed by the benthic diatom Didymosphenia geminata (didymo) have been spreading rapidly, with negative ecological and economic effects. This microscopic alga is transported on fishing equipment, and controlling the spread of didymo involves proper cleaning of gear. Our study experimentally tested several common decontamination treatments and determined the response of state agencies and fishermen to decontamination procedures. In testing decontamination products, we found that dish liquid detergent was the most effective, followed by bleach, Virkon, and salt. Decontaminants were more effective on cells that were not still attached to their stalks. From the fishermen's perspective, didymo was the aquatic invasive species of highest concern, but there was a wide range of approaches to didymo control. Our final recommendations concentrate on the importance of comprehensive information sources and standards for didymo decontamination and education, specifically, and for invasive/nuisance species more generally.

RESUMEN

Los afloramientos nocivos generados por la diatomea Didymosphenia geminata (didymo) se han expandido rapidamente, provocando efectos ecológicos y económicos negativos. Esta alga microscópica es transportada en equipos de pesca y su control implica una limpieza adecuada de los artes. En este estudio experimental se prueban varios tratamientos descontaminantes y se estudia la respuesta de las agencias estatales y de los pescadores ante los procedimientos de descontaminación. Al probar los productos descontaminantes, se encontró que el líquido detergente para trastes fue el más efectivo, seguido por los blanqueadores, el Virkon y la sal. Los descontaminantes probaron ser más efectivos en las células que aun no se encontraban fijas a su tallo. Desde la perspectiva de los pescadores, didymo fue la especie acuática invasiva de mayor cuidado, pero hubo una enorme variedad de enfoques para el control del alga. Las recomendaciones finales se concentran, de manera general, en la importancia de fuentes de información comprensibles, estándares para la descontaminación por didymo y educación, y de manera particular en el control de especies invasivas/nocivas.

ACKNOWLEDGMENTS

The authors would particularly like to thank Dave Kumlien at Trout Unlimited for facilitating the survey; David Richardson at SUNY New Paltz for getting us involved in didymo research on the Esopus Creek, New York; Cathy Kilroy at the New Zealand National Institute of Water and Atmospheric Research for early discussions regarding our results; and Anna Paltridge at the New Zealand Department of Conservation for providing information about New Zealand's decontamination stations. Laura Achterberg, Molly Redfield, and Sean Steeneck helped with fieldwork. Funding was provided by NSF REU #0851022 (PI: Chowdhury), WRI/HREP Grant 2010 (PI: Richardson), and the Bard College Biology Program.