What type of pest can create health and safety hazards in aquatic systems?

In the context of aquatic systems, invertebrates can pose significant health and safety hazards primarily due to their role as vectors for diseases or as nuisances that can impact water quality and ecosystem balance. Many invertebrates, such as certain species of mosquitoes and other aquatic insects, can carry pathogens that affect humans and animals, leading to health risks like infections or diseases such as West Nile virus and Zika virus. Additionally, nuisance invertebrates can proliferate and disrupt recreational activities in water bodies, leading to safety concerns for swimmers and boaters.

While fish, crustaceans, and amphibians each have their ecological roles, they are generally not classified in the same way concerning direct health hazards in aquatic environments. For example, while certain fish can carry parasites or diseases, they do not typically serve as vectors like certain invertebrates do. Crustaceans may impact the ecosystem and food web but are not primarily viewed as health hazards. Amphibians, although they may have pathogens on their skin, are not as commonly associated with direct human health risks compared to the broader range of disease vectors found among invertebrates. Therefore, invertebrates distinctly represent a category of pests that can directly create health and safety hazards in aquatic systems.