SHELLFISH HATCHERY CRASHES ALONG THE ATLANTIC COAST OF THE UNITED STATES: A CALL TO ACTION

Oyster aquaculture in the United States is highly dependent on hatchery-produced oyster seed to fuel production. The role of hatcheries has also expanded over time to support fisheries augmentation and restoration efforts. Given the importance of hatcheries for commercial aquaculture and increasingly for oyster restoration projects, considerable effort has been placed on increasing the output and production efficiencies of these facilities through improved husbandry practices and technological development.

Despite these resulting improvements, many hatcheries regularly experience substantial and unexplained die-offs or prolonged periods of slow larval growth (termed crashes) without clear signs pointing to causative factors. The frequency (e.g. decadally , annually, etc.), scale (i.e. amount of larvae lost), and the duration of crashes varies greatly among hatcheries. At a minimum, short-lived hatchery crashes waste valuable resources (i.e. labor, utilities, broodstock, etc.), but prolonged droughts in production among larger facilities are likely to limit regional shellfish production through seed shortages. Although crashes are well recognized within the industry, effective diagnostic and response strategies are ineffective. Indeed, hatchery staff are often forced to focus on one potential cause and simply dispose of the 'bad' larvae and water, and hope 'good' water will be available upon restarting the production process. Research is needed to improve production reliability by predicting, diagnosing, and mitigating sources of hatchery crashes.

Here we review recent crashes at research hatcheries along the Atlantic Coast and note facilities experiencing fewer crash events. Attention is given to a recent, prolonged crash at the Horn Point Laboratory Oyster Hatchery (Fig. 1) , the largest hatchery supplier of oyster larvae and seed on the Atlantic Coast. We describe the complexity of identifying sources and discuss how crashes affect hatchery profitability, growers, and shellfish management and policy. Finally, we offer new approaches and strategies for identifying and avoiding crashes to maintain shellfish production.