The role of climate forecasts in early warning systems for harmful algal blooms that impact human health

Harmful algal blooms (HABs) are natural phenomena caused by the proliferation of algae. Many produce toxins that accumulate in fish and shellfish and cause illness or death in humans if consumed. Increasingly, local and large-scale climate processes are being recognized as important factors in (1) creating oceanographic conditions that are favorable for the growth and development of toxic HABs, and (2) transporting HABs and/or their toxins to coastal regions where they can contact humans. It is not surprising then that climate forecasts are critical components in a variety of early warning systems that are currently being used to assess the risk of HAB events. The timescale of climate forecasts determines the management options that are available to state health officials and resource managers. For HABs with strong links to large-scale climate patterns, such as El Niņo, advanced warning of up to a few seasons is afforded by long range climate forecasts. This allows health officials to issue advisories and plan targeted monitoring efforts for the coming bloom season. Other HAB early warning systems rely on shorter term weather forecasts, such as wind speed and direction. In this instance, health officials have a matter of days to alert coastal communities and prevent the harvesting and consumption of contaminated seafood. This talk will discuss the role of climate forecasts in some operational HAB early warning systems in the U.S. and present new research linking long-term climate patterns to increased shellfish toxicity due to HABs in Puget Sound, Washington State.