HABs, Camera, Action! - Revealing the Behavioral Toxicity of Harmful Algae to Coastal Forage Fish Using Video Analysis

Harmful algal blooms (HABs) have increased in geographic extent, frequency, and duration in coastal areas worldwide. These blooms have negatively impacted many coastal fisheries, causing mass mortalities of both wild and farmed fish. Forage species may be particularly susceptible to HABs as they feed on plankton and are highly abundant in coastal ecosystems where these blooms occur. While mortalities associated with HABs have been well documented for fish, the potential sublethal impacts to fish behavior have not been adequately explored. We developed and conducted a series of laboratory experiments using juvenile and larval life stages of forage species common to the U.S. East Coast. Experiments utilized an HD video camera system that recorded the behavior of fish when exposed to different species of harmful algae. Recorded fish were tracked using LoliTrack v.4 software and changes in their behavior (i.e. swimming speed, acceleration, and time active) were analyzed. Our results demonstrate differences in behavior between fish species and across the harmful alga tested. This research provides ecologically relevant information and insights into how fish distributions may be affected when HABs occur in coastal waters.