Zebra mussel control using Zequanox® in an Irish waterway

Abstract

Due to the invasion of zebra and quagga mussels in European and North American waters, there is a need for an environmentally benign mussel control method to replace chlorine and other currently used control products. Zequanox ® is a natural product comprised of Pseudomonas fluorescens strain CL145A, which effectively controls zebra and quagga mussels. The objective of this study was to demonstrate an effective method of zebra mussel control in inland waterways using Zequanox. Water quality was monitored to determine any negative impacts and to observe product dispersion. A curtain made of an impermeable material was placed in the Grand Canal at Tullamore Harbour sealing off two 8  0.5 m sections of canal wall under the bridge, and a control site was chosen further down the docking area. Both sections were treated with Zequanox at a concentration of 150 mg active substance/L for an 8 hour treatment period. Water quality was monitored in the treatment area and in the selected control area before, during, and after treatment. Naturally settled and seeded adult zebra mussels were observed for mortality in the treatment and control areas and juveniles were monitored for survival in both the treatment and control areas. Naturally settled adult mussel numbers were reduced by approximately 46% in treatment side 1, and 65% in treatment side 2, seeded adult mussel mortality reached 75% in treatment side 1 and 56% in treatment side 2. These results demonstrate that under the optimum conditions Zequanox effectively controls zebra mussels in open water.