Canada’s honeybee winter losses attributed to poor weather
Five of the 10 provinces reported weather as the primary cause of honeybee winter loss in 2018-19
It’s no secret Canada’s weather was harsh at times this winter and spring, which was cited most frequently as the primary cause for honeybee winter losses in 2018-19.
This is according to the Canadian Association of Professional Apiculturists (CAPA), who, this week, released its findings of Canada-wide colony losses in this past winter season. CAPA works with provincial apiculturists to report on wintering losses of honeybee colonies and possible causes of bee mortality across the country.
The objective of the national document is to consolidate provincial honeybee losses across the country based on data collected through harmonized survey questions.
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The 536 sideline and commercial beekeepers who responded, representing 44 per cent of all surveyed targeted apiarists, were asked to identify and rank the top four possible causes of colony losses across the country.
In order, the most frequently cited causes were weather, starvation, poor queens and weak colonies in the fall. Five of the 10 provinces reported weather as the primary cause (B.C., Alberta, Ontario, Quebec and P.E.I.).
“Weather was considered an important factor for winter loss across the country, likely reflecting the very long and cold winter, in addition to the cold periods of weather well into April and May through many beekeeping areas,” CAPA said in the findings.
“In six provinces, weather was considered the No. 1 (five provinces) or No.2 (one province) factor contributing to reported winter losses. Similar to the previous year, beekeepers reported that a lot of bee colonies died in April and into early May.”
WINTER LOSS RATE DROPS
This year's national winter loss, including non-viable bee colonies, was 25.7 per cent with provincial numbers ranging from 19.8 per cent to 54.1 per cent. The latest figure decreased slightly from 2017-18, which had a loss rate of 32.6 per cent.
The most frequently cited causes for wintering losses in 2018-19 were weather, starvation, poor queens and weak colonies in the fall. Photo: Nathan Howes.
According to CAPA, the overall national colony loss reported in 2019 is considered to be in the middle range of reported mortalities since 2007.
"Through the hard work of beekeepers replacing loses and making increases, Statistics Canada reports show that the total colony count has increased by 35.2 per cent during the period between 2007 and 2018," the report said.
Most provinces reported a lower mortality rate in 2018-19 than the previous year, with the exception being Nova Scotia, which had similar losses to last year and had the lowest percentage of deaths this year at 19.8 per cent.
P.E.I. and Newfoundland reported higher mortality rates than last year, with their numbers reaching 54.1 per cent and 29.8 per cent, respectively.
NUMBER STILL HIGHER THAN ACCEPTABLE THRESHOLD, CHALLENGES CONTINUE
Although the loss rate improved slightly from last year, the figure is still considered to be higher than the long-term suggested threshold for winter losses, which is 15 per cent. It is a number that has never been reached since CAPA's survey began in 2007.
The national winter losses were highest in 2008, 2009 and 2018, which ranged from 32.6 per cent to 35 per cent. From 2010 to 2019, the national winter losses ranged from 15.3 per cent to 32.6 per cent, averaging 23.6 per cent.
The national 2018-19 winter loss of honeybees, including non-viable colonies, was 25.7 per cent with provincial numbers ranging from 19.8 per cent to 54.1 per cent. Getty Images.
Since 2007, CAPA said beekeepers have faced a number of challenges in keeping colonies thriving including pest management, climatic condition, bee nutrition and bee exposure to pesticides in hives and the environment. As well, another obstacle is the economics of beekeeping.
"It appears that stresses caused by parasites and a combination of other stressors warrants further studies to provide alternative management practices to maintain honeybee health," CAPA said. "At this time, beekeepers have few products to control Varroa [mites]. New options are important to mitigate the risk of developing resistances."
The report stated beekeepers will need more effective and additional options (miticides, antibiotics and non-chemicals) in order to continue effective, integrated pest management to maintain healthy bees.