The Effectiveness of Carbon Dioxide As a Non-Physical Barrier for Fish Movement

Invasive Asian carp are currently contained within the Mississippi River basin by electrified barriers.  Development of novel barriers would provide additional means to prevent Asian carp from spreading.  This presentation summarizes two studies designed to quantify the effectiveness of CO₂ to act as a non-physical barrier.  First, pond experiments were performed to identify if the movement of free-swimming fishes in a field setting would be influenced by the presence of a zone of elevated CO₂.  Second, the capacity for physiological acclimation following extended exposure to CO₂ was also explored. Results demonstrate that free-swimming fishes in a pond environment will avoid areas of elevated CO₂, and that it is indeed feasible to treat large volumes of water (almost 2 million gallons) with CO₂ to a level that excludes fish.  In addition, extended exposure to CO₂ will induce changes to physiology and performance, but will not alter thresholds of avoidance. Together, these two studies demonstrate that CO₂ has potential as a barrier to prevent the spread of Asian carp, and that the barrier has potential to be applied over extended time periods and at large scales.