Which statement about Gambusia species for mosquito control in Maryland is true?

• A. Gambusia affinis is native to Maryland and is used for mosquito control.
• B. Gambusia holbrooki is not effective for mosquito control.
• C. Gambusia holbrooki is native to Maryland and effective for mosquito control.
• D. Gambusia affinis is native to Maryland and also used.

Answer: (C)

The key idea is native status matters for ecological compatibility and practical control in Maryland. The eastern mosquitofish, Gambusia holbrooki, naturally occurs in Maryland waterways, and like other mosquitofish, it feeds on mosquito larvae in still or slow-moving waters, helping to reduce the number of mosquitoes that reach adulthood when it’s present in suitable habitats. Being native means releasing it is more ecologically appropriate and less disruptive to local fish communities than introducing a non-native species. In contrast, Gambusia affinis is not native to Maryland and, although used elsewhere for mosquito control, carries ecological risks and regulatory concerns because non-native fish can outcompete or disrupt native species. So, Gambusia holbrooki being native to Maryland and effective for mosquito control aligns with both ecological suitability and practical larval reduction, though real-world effectiveness depends on habitat conditions and should be part of an integrated control approach.