Over the last 2 decades, several reports have compiled what is known about the economic effects of harmful algal blooms. However, both the type and amount of available data are limited, and these reports largely have been compiled by marine scientists rather than economic experts. Most coastal states have neither conducted economic analyses of HABs nor collected data that can be used to generate reliable quantitative estimates of net economic losses and economic impacts. Proposals submitted to NOAA for economic impact studies demonstrate this lack of coordination; they are strong either in the HAB science or economic assessments, but not both. This 2.5 day international workshop bring together international experts on economics and the science of harmful algal blooms to develop a best practices manual for the study of economic impacts of HABs. The workshop structure is: Day 1: Recommended practices for 4 specific HAB examples – Consideration of 4 case studies of HABs globally, including losses to aquaculture, 2 wild fisheries and a recreational fishery. Breakout groups will discuss value of information from better or more refined forecasts and best practices for economic assessment, including economic impacts and net economic losses. Day 2: Strategies for economic mitigation - Can contingency planning reduce losses, how do we open areas more quickly, how do we make closures shorter, and what is the value of information from better forecasts? In particular, we will discuss approaches for assessing the value of the forecasts versus the cost of monitoring. Day 3 (half day): Social science - Discussion of social science impacts and how to assess impacts on health (including mental health), well-being, resilience of coastal communities (non-financial impacts). Wrap up and writing assignments. The workshop will provide science-based progress towards achieving ocean Sustainable Development Goals. The output will be a guide on best practices for quantifying economic effects of HABs that focuses on establishing connections between researchers and economists. A shorter version of the guide may be prepared for submission to a journal. The workshop also will (1) set priorities for the future, (2) develop partnerships between social scientists, economists and HAB researchers, and (3) attract resources to the field.

Vera L. Trainer (USA), corresponding Keith Davidson (ICES, WGHABD) Kazumi Wakita (Japan)