News features and technical articles about the evolution of aquaculture, one of the world’s fastest growing industries.

Toxicity

Responsibility

Toxicity of chemical substances in aquaculture

Prof. Boyd discusses toxicity of chemical substances in aquaculture systems and the difficulties in establishing safe concentration limits for toxic metabolites. 

Responsibility

Examining copper use in aquaculture

Copper is used for control of the blue-green algae responsible for off-flavors in aquaculture animals, treating diseases and parasites, and avoiding cage net fouling. Although copper is an essential nutrient for plants and animals, an excess can negatively affect the 

Health & Welfare

Ammonia toxicity degrades animal health, growth

Ammonia nitrogen occurs in aquaculture systems as a waste product of protein metabolism by aquatic animals and degradation of organic matter, or in nitrogen fertilizers. Exposure can reduce growth and increase susceptibility to diseases in aquatic species. 

Health & Welfare

Toxicity vs. detection

The 2001 detection of chloramphenicol in shrimp imported into the Netherlands heightened awareness of and anxiety over the presence of chemicals in food. 

Responsibility

Trace metals toxic at high concentrations

Excessive concentrations of trace metals, especially copper, are toxic to phytoplankton and other aquatic plants. The ionic forms of trace metals are toxic to fish and other aquatic animals, but soluble, chelated trace metals are relatively non-toxic. 

Responsibility

LC50 calculations help predict toxicity

LC50 – the concentration of a substance that is lethal to 50 percent of the organisms exposed to it in a toxicity test – is a useful tool because it can predict the effects of a potential toxin in aquaculture