Abstract:
Cyanobacteria, or blue-green algae, can form harmful algal blooms (HABs) in freshwater
environments that have been linked to disruptions in neurofunction, growth, and survival.
Emerging research suggests that cyanotoxins produce non-lethal, but substantial effects on
resident aquatic wildlife, including alterations in the central nervous system and behavior.
However, little is known about how HAB-induced changes in the behavior of affected organisms
influence fitness. This deficit in knowledge is important because the effects of exposure to
neurotoxins on species interactions is critical in accurately producing risk assessments for
population and community level outcomes. The aim of this project was to evaluate the shortand long-term effects of exposure to 2,4-diaminobutyric acid (DABA) on the cognitive and motor
performance of fish while foraging for live prey. The central hypothesis of the project was that
chronic, low-dose exposure to neurodegenerative cyanotoxins would alter the outcome of
predator-prey interactions through disruption of sensorimotor feedback during prey-capture
events. To test this hypothesis, data were collected on the prey-tracking performance of larval
(21 days) and adult (7-8 months) fathead minnows, Pimephales promelas, during hunting
events under lab conditions. Foraging efficiency and prey-capture trials indicated that exposure
to DABA was associated with a significant reduction in prey consumption, potentially due to a
reduced ability to detect or recognize prey. Sensorimotor deficits of fathead minnows under lab
conditions suggest that these effects would also be apparent in wild populations. A permanent
or temporary reduction in motor performance can interfere with prey-capture behavior and
decrease capture success. Such changes are important because they have the potential to alter
the dynamics of aquatic populations and communities if they translate into increased mortality.
