Understanding and Assessing Impacts
The BC shellfish industry generates $47 million dollars annually and employs up to 800 people in direct full-time jobs. The industry primarily produces Manila clams and Pacific oysters, the latter typically for high-end markets, such as upscale restaurants, that offer farmed oysters on the half shell. These oysters attract a premium price in the marketplace. An increased demand exists for BC oysters, but opportunities for the local oyster industry to expand are restrained by the industry’s ability to produce and grow the shellfish. A major issue continues to be the high mortality rates experienced by oyster farms due to summer mortality syndrome, with farms experiencing up to 90% mortality in recent years. Summer mortality of Pacific oysters is very common in BC and the BC Shellfish Growers Association estimates that, on average, 50% of adult oysters cultured in deep-water sites die from summer mortality each year. Anecdotal evidence from oyster farmers indicates that summer mortality on farms in Baynes Sound has substantially increased over the past decade, with losses occurring every summer. Mortality rates typically range from at least 30% but can extend to near total loss. The specific causes of BC oyster mortality events are unknown, but recent research has shown field mortality to be positively correlated with temperature (typically occurring when summer temperatures are >20°C), reproductive condition, and the presence of certain pathogenic bacteria.
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