HABs in a changing world: a perspective on harmful algal blooms, their impacts, and research and management in a dynamic era of climactic and environmental change.

More than 25 years ago, the author was asked to provide a retrospective analysis of the global status of what were then called “red tides”, but are now known as “harmful algal blooms” or HABs. The occasion was an international conference in Takamatsu, Japan (Okaichi et al. 1989), convened at a time when algal blooms seemed to be affecting more and more countries and causing increased economic losses through a growing number of impacts, but long-term trends were anecdotal and speculative. The challenge was a significant one: to evaluate blooms of many different types of algae – some producing toxins that could affect humans, fish, shellfish, and many different marine organisms and ecosystems, some causing harm in a multitude of other ways – and then assess whether the problem was indeed “growing worse” on a global basis. The resulting paper (Anderson 1989), though highly qualitative in its approach and content, helped to ignite a scientific discussion that motivated many studies and publications, some arguing that indeed the HAB problem was growing worse as a result of pollution (e.g., Smayda 1989) or other factors such as expanded aquaculture operations or ballast water transfer of species (e.g., Hallegraeff 1993), while others contended that the “global expansion of HABs” was not accepted by all or was being exaggerated by scientists and the press. Skeptics counseled caution and argued that the increased number of toxins and impacted resources had other causes, including the simple discovery of toxins and toxic species that had always existed. It is now clear that the “global expansion” of HAB phenomena is real, due in part to our ability to better define the boundaries of the problem. However, those boundaries are not static, but continue to expand due to natural dispersal via storms or currents, as well as to effects from human influences, such as pollution, aquaculture expansion, and ballast water transport. The fact that part of this expansion is simply because of increased scientific awareness and detection capabilities should not temper our concern. The global problem of HABs is serious and much larger than we thought. Now, at the 15th International Conference on Harmful Algae in Korea in 2012, a new challenge has been posed – this time to look forward and envision the nature of HABs, the field of HAB science, and the nature of HAB impacts and management in an era where so many features are changing rapidly due to population pressures, climactic shifts, and many other global, regional, and local forcings. Motivation for this request reflects a desire to anticipate changes that can guide research priorities, technology development, and social and commercial policies in areas that are either affected by, or that affect, HABs. The following thoughts are offered in the same manner as those written in the 1989 retrospective – as personal views offered in hopes that others will expand on these ideas and ultimately create a scholarly and comprehensive perspective on the future of HABs in a changing world.