Winter bee mortality rates seem to be dropping, according to data submitted to Health Canada by the Canadian Association of Professional Apiculturists.
The group told the Health Department, that has been heavily involved in a multi-stakeholder study into the issue, that all provinces either saw similar death rates, or lower death rates than the previous several years.
The national average of colony winter loss was 16.4 per cent for 2014-15, the latest season for which data is available, CAPA says. Overall, the reported national colony loss is one of the lowest levels since 2006-07 and represents a decrease of 34.4 per cent from 2013-14 winter losses.
Provincial averages ranged between 10.4 and 37.8 per cent. Colony winter loss in Ontario was 37.8 per cent, a decrease by 34.8 per cent compared to the 58.0 per cent loss reported in 2013-14.
“Bee health is complex and many factors are involved, including hive conditions, weather and starvation,” a Health Canada spokesman said. The department is one of a number of key government organizations and stakeholders participating in the effort to address bee losses.
CAPA, also a member of the Bee Health Roundtable, says it asked a set of harmonized questions of beekeepers across Canada who own 362,949 honey colonies. This represents 50.8 per cent of all colonies operated and wintered in Canada in 2014.
“Respondents reported considerable variation in identifying and ranking the top four possible causes of colony losses. Answers included starvation, weak colonies, poor queens, Nosema and weather conditions,” CAPA said.
CAPA has been tracking wintering losses of bee colonies and possible causes of bee mortality since 2007 “to consolidate provincial losses for a national representation, to present the possible main causes of winter losses, and to provide information for pest surveillance and control. These results provide information needed to identify gaps in current management systems, to develop strategies to mitigate bee colonies losses and to improve bee health.”
This set of data is considered one of the lowest average losses in the last eight years since the national survey commenced. It represents a 34.4 per cent reduction over the previous years’ winter losses (2013-14).
The Prairie provinces benefited from favourable winter and spring conditions and reported an average of 11.1 per cent winter losses in 2014-15. Overall, the 2014-15 winter loss in most of the provinces, except Ontario, were close to or better than what beekeepers reported as an annual acceptable long-term loss.
CAPA notes that several beekeepers in different provinces reported that they did not know why their colonies died. If beekeepers are unable to identify a possible cause for the mortality of their colonies, it may be because of multiple underlying problems, or a lack of monitoring colony health status throughout the season.
“In recent years, pest management has become a widespread practice by beekeepers to ensure keeping healthy honeybees,” CAPA points out. “Lack of monitoring bee health status and determining levels of infestation by pests can be a serious problem as reported in previous years. Therefore, this survey focused on asking beekeepers questions about management of three identified serious pests and diseases that could impact bee health and productivity.
“Varroa mite infestation continues to be considered by beekeepers and bee specialists as one of the main cause of honeybee colony mortality. Although very few concerns regarding varroa were cited by beekeepers in the 2014-15 survey, sustained monitoring and management of varroa in honeybee colonies have been widely recognized as most important factors to keep healthy honeybee populations in Canada.”
Educational programs delivered to beekeepers in Canada “have made a difference in the application of proper beekeeping management practices for varroa mites,” CAPA says. “Implementing surveillance and monitoring programs for varroa mites enables beekeepers to successfully adopt principles of integrated pest management (IPM) to determine the right timing and select the best treatment options for varroa mites.”