The Canadian Association of Professional Apiculturists (CAPA) has just issued its final report on overwintering losses of honey bees in Canada, and the picture is not a pretty one — although New Brunswick beekeepers fared a bit better than we have in the past few years.

Nationwide honey bee losses of 35% over the winter of 2007-2008 are up from last year’s mortality rate of 29% of colonies, and more than double the long-term “normal” of 15% that Canadian beekeepers were accustomed to seeing before the arrival of the Varroa destructor mite in this country.

“Successive annual losses at levels exceeding the long-term average are unsustainable by Canadian beekeepers,” CAPA warns, “and are likely to lead to decreased honey production and shortages of colonies available for pollination. Indeed, more demand than supply was evident for pollination in British Columbia during the spring of 2008, where some blueberry pollination contracts were not entirely fulfilled.”

Honey Bee Losses in Canada (by Province) 2007-2008

Above-average losses hit Alberta (44%), British Columbia (38%) and Prince Edward Island (36%), with Ontario not far behind at 33% of colonies lost over the winter. New Brunswick beekeepers reported a better winter than in the past few difficult years, with losses of 29% of managed colonies. The lowest mortality rates were reported in Quebec and Nova Scotia, at 19% and 18% respectively.

These statistics refer to colony losses reported as of 30 May 2008, and they include losses due to spring dwindling as well as those honey bee colonies that died through the winter months. In Alberta, the spring dwindling component (14%) was defined as the number of weak colonies having three frames of bees or less.

“Though high losses for individual producers may occur in any given year, high regional losses are of potentially greater concern,” says CAPA. “Across the country any unusually high losses have been investigated by provincial apicultural specialists. Initial indications suggest that these losses may be attributed to the three principal causes, listed in descending order of importance”:

1. Ineffective control and mismanagement for the parasitic mite, Varroa destructor;
2. Inadequate control of the internal parasites Nosema apis and Nosema ceranae; and
3. Starvation. Inadequate nectar flows and fall feeding in some areas prevented colonies from storing enough nectar or sugar syrup to survive all through the winter.

Comparable 2007-2008 Losses by US Beekeepers

The Canadian experience matches that of beekeepers in the United States, where surveys commissioned by the Apiary Inspectors of America (AIA) and the USDA-ARS Beltsville Honey Bee Lab recorded a total loss of 36% for managed honey bee colonies in 2008. This represents an increase of 13.5% increase in total losses compared with the US figures for 2007.

“The survey commissioned by the AIA was not able to differentiate between true cases of Colony Collapse Disorder (CCD) and colonies lost due to causes that share the ‘absence of dead bees’ symptom that is typically associated with CCD,” the CAPA report notes.

Interestingly, “at least 71% of all operations had no CCD-like symptoms in any of their colonies that perished, underlying the need for research, not only into CCD, but into pollinator health in general.”