Protecting Alberta's Irrigation Infrastructure Against the Threat Of
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Protecting Alberta’s irrigation infrastructure against the threat of aquatic invasive species. For more information, please contact: Nicole Seitz, Water Research Specialist Water Quality Branch, Irrigation and Farm Water Division 403-382-4713 [email protected] Adult quagga and zebra mussels are about 15-20mm in size. 2 Introduction and Background Aquatic invasive species (AIS) are animal, plant, or pathogen species that are not native to Alberta and pose significant threats to the environment, economy, and society due to their high reproduction rates, ability to thrive in non-native environments, and the difficulty involved in controlling and containing them. Zebra and quagga mussels are small freshwater invasive mollusks which are two AIS of significant, immediate concern, particularly for the irrigation industry. Though not currently considered present in Alberta, once these mussels are introduced to a water body, they adhere to virtually any hard surface in the water, including docks, boats, and infrastructure such as water treatment or conveyance works. Zebra and quagga mussels spread quickly and are very resilient. In fact, one female mussel can produce up to one million eggs per year, and adult mussels in general can survive out of the water for up to 30 days. This makes them impossible to eradicate, and control options are very limited. Alberta boasts several thousands of kilometers of irrigation canals and pipelines which could become clogged or fouled should mussels be introduced to an irrigation reservoir (Figure 1). This would result in reduced pumping volume and water conveyance to crops, as well as increased costs to users. In fact, a conservative estimate states that an infestation of invasive mussels in Alberta could cost more than $75 million annually to control and manage on an ongoing basis- a large loss for the economy. Figure 1. Examples of mussel-fouled pipes. Invasive mussels are typically transported or ‘hitchhike’ on trailered watercraft from infested waters, whether they are as attached adults or as microscopic larvae in ballast waters and bait buckets. Because several of southern Alberta’s popular boating lakes also serve as irrigation reservoirs, the threat of an invasive mussel infestation is very real. Prevention is the only management strategy for invasive mussels because control options are limited and costly. The Government of Alberta recognizes this threat, and is developing a province-wide AIS prevention program lead by Alberta Environment and Sustainable Resource Development. Program partners also include Alberta Tourism, Parks and Recreation; Alberta Agriculture and Rural Development (ARD); and several other stakeholders. Key aspects of the program include education and outreach, developing rapid response protocols, boat inspections, changes to legislation, and monitoring. ARD has been actively involved in monitoring for invasive mussels in several irrigation reservoirs in southern Alberta over the past two years. Veligers are the microscopic, larval form of zebra and quagga mussels. They float freely in the water column until they filter enough mass to sink, settle, and attach to the nearest hard surface. Veliger monitoring requires the use of a fine filter net, as well as a boat in order to reach optimal locations for veliger sampling on the reservoir. All monitoring showed that results were negative 1 for the presence of veligers in Alberta in 2013 and 2014. Artificial substrates were also provided to irrigation districts and installed within several irrigation reservoirs beginning in 2013. The substrates were constructed of PVC pipe filled with cement, and were installed near easy access locations and infrastructure, namely docks and boat launches. The substrates provide a solid surface on which invasive mussels can attach. All substrate reports submitted indicated no detection of mussels in 2013 or 2014. In addition to monitoring, ARD has been proactive in getting the word out about the threat of invasive mussels to boaters and water users. As well, several irrigation districts have been invaluable and active partners to the provincial program by providing assistance by putting up signs at boat launches, and contributing to a provincial billboard campaign. These efforts are needed to change the attitudes and behaviours of boaters, and to ensure that Alberta remains free of invasive mussels. Recap of 2013 In 2013, 21 irrigation reservoirs were identified by Alberta Agriculture and Rural Development (ARD) and partners as high priority for aquatic invasive species (AIS) monitoring because of the recreational opportunities offered, such as boating and fishing, and associated implications of AIS being introduced by boat. Of these 21 reservoirs, 15 were monitored for veligers by ARD in September 2013 (Table 1; Figure 2). Veligers are the microscopic, larval form of zebra and quagga mussels. They float freely in the water column until they filter enough mass to sink, settle, and attach to the nearest hard surface. Veliger monitoring requires the use of a fine filter net, as well as a boat in order to reach optimal locations for veliger sampling on the reservoirs (Figure 3). Alberta Environment and Sustainable Resource Development (ESRD) also performed veliger sampling at several Alberta lakes beginning in 2013 as part of their annual water quality monitoring efforts. ESRD’s annual water quality monitoring efforts involves monitoring a selection of lakes across the province, which changes on a rotational basis annually, so that different lakes are monitored each year. In 2013, six waterbodies included on ARD’s list of priority waterbodies were monitored by ESRD (Table 1). Between ESRD and ARD, approximately 55 waterbodies altogether in Alberta were monitored for veligers. All monitoring showed that results were negative for the presence of veligers in 2013. Artificial substrates were also provided to irrigation districts and installed within several irrigation reservoirs beginning in 2013 (Figure 4). The substrates provide a solid surface on which invasive mussels can attach. The substrates were constructed of PVC pipe filled with cement, and were installed near easy access locations and infrastructure, namely docks and boat launches. Monitoring of the substrates included a reporting procedure where data was gathered by completing an inspection report form. The forms were to be faxed or emailed to ARD. The results were then forwarded to ESRD. Substrates were installed in August, and checked in mid- August and mid-September. All substrate reports submitted indicated no detection of mussels in 2013. 2 Figure 2. Map of locations where ARD performed veliger sampling in 2013. 3 Figure 3. Biological sampling for veligers requires the use of a fine filter net and a boat for lake access. Figure 4. A PVC substrate. Monitoring in 2014 Methods. In addition to ESRD and ARD, other government ministries and non-government stakeholders monitored veligers in additional lakes and reservoirs within Alberta in 2014 (Table 2). These stakeholders include Alberta Tourism, Parks, and Recreation (TPR); The City of Calgary; and the Alberta Lake Management Society (ALMS). In 2014, ESRD’s monitoring rotation included only two of ARD’s identified high priority irrigation reservoirs, and TPR monitored one of ARD’s identified high priority irrigation reservoirs (Table 1; Figure 5). This meant that instead of six out of the 21 reservoirs that were monitored by other stakeholders in 2013, only three were monitored in 2014. Because ARD only had the capacity to monitor 15 reservoirs, 18 out of the 21 high priority irrigation reservoirs were monitored for veligers in 2014. ARD chose the 15 reservoirs to monitor for veligers in 2014 based on highest boating activity (Figure 6). 4 Figure 5. Map of locations where ARD performed veliger sampling in 2014. 5 Figure 6. Different types of boating activities observed during 2014 veliger sampling at irrigation reservoirs, including fishing/angling, and recreational (sailing, water skiing). In 2014, two veliger monitoring events were performed by ARD, as opposed to only one in 2013. The first veliger monitoring event began on July 2nd, and the second event began on August 21st. Each sampling took about 10 days to complete. Veliger sampling sites in each reservoir included an open, deep-lake reference site, as well as at two additional sites such as docks, boat launches, and irrigation outlets (Figure 7). In some instances, lakes that were very small and shallow, such as Park Lake and Chestermere Lake, warranted performing a horizontal tow, during which the sample net was attached to a pole and pulled through the water for a specified speed and distance. All samples were preserved and sent to the lab for analyses. Figure 7. Examples of veliger sampling sites at an irrigation outlet (left) and a boat launch (right). The artificial substrates used in 2013 were re-installed in early May 2014 at the same locations. Substrates that were installed in reservoirs in 2013 that were damaged or went missing were replaced in 2014. The irrigation districts were asked to report on a monthly basis using the same reporting procedure as in 2013. Results In 2014, all veliger samples that were sent to the lab were negative for the presence of veligers. As well, none of the substrate reports indicated the presence of juvenile or adult invasive mussels. 6 Monitoring Challenges. The strong winds that can occur in southern Alberta often influenced ARD’s field plans. It was found that anything above 20 km/hr was not only too dangerous, but made it near impossible to accurately perform veliger sampling. Often the monitoring staff were forced to wait for a day when the wind was calm, and this delayed sampling events. The substrate monitoring program had its challenges as well. Irrigation districts found that in some cases, the rope connecting the substrate to the infrastructure in the water had been severed, whether it be from beavers/muskrats, or vandals. At least 150 substrates had been distributed to 10 irrigation districts during the last two seasons, which included many replacement spares.