Using osmotic shock to control invasive aquatic species

Area of Science:

• Marine Biology
• Ecology
• Invasive Species Management

Background:

• Coastal estuaries are highly susceptible to invasive aquatic species (IAS) introductions via shipping.
• Effective rapid response tools are crucial to prevent the spread of IAS from estuaries into adjacent ecosystems.
• Abrupt salinity changes in estuaries offer a novel, low-cost, and eco-friendly method for IAS control.

Purpose of the Study:

• To investigate the efficacy of osmotic shock via salinity changes for controlling the invasive brackish water clam, Rangia cuneata.
• To determine the lethal salinity thresholds and exposure durations for R. cuneata.
• To assess the potential of salinity manipulation as a management strategy for IAS in estuarine environments.

Main Methods:

• Laboratory experiments exposing R. cuneata to eight salinity levels (0.5–32.0‰) for 60 days.
• Monitoring clam mortality rates at different salinity concentrations.
• Comparing the impact of saline shock versus freshwater shock on clam survival.

Main Results:

• Saline shock proved effective in controlling R. cuneata, while freshwater shock did not.
• Salinities exceeding 26‰ resulted in 95% mortality within two weeks.
• Exposure to full seawater (32‰) led to complete mortality within 30 days.
• Clams from less saline environments exhibited lower mortality at lower salinities.
• Elevated salinity during spawning periods could inhibit R. cuneata recruitment.

Conclusions:

• Saline flushing is a promising and effective management tool for controlling invasive species like R. cuneata in coastal estuaries.
• The study highlights the vulnerability of estuarine ecosystems to IAS and the potential of environmental manipulation for control.
• This method offers a potentially sustainable and low-cost approach to invasive species management in sensitive aquatic habitats.