Shrimp trawling is considered one of the most wasteful kinds of commercial fishing because of the immense volume of marine life that is incidentally captured and destroyed in shrimp nets. The bottom trawls that are dragged over the ocean floor can also damage marine ecosystems.
Industrial-scale shrimp aquaculture can also involve negative impacts on fragile wetland habitats that are vital to fisheries and coastal communities in countries like Thailand, Vietnam and Indonesia. In most of the countries that farm shrimp, shrimp farms have been plagued with bacterial and viral diseases that infect the ponds. In some countries there has been a widespread use of antibiotics and other chemicals to contain these diseases, a practice that is often ineffective. Many medical scientists are concerned that the indiscriminate use of these antibiotics has the potential to develop disease-resistant pathogens that pose a danger to humans. The saltwater effluent routinely discharged from many shrimp farms can also be a serious problem for nearby communities where freshwater aquifers have been polluted and croplands ruined due to salinization.
In recent years the industry has made progress in addressing some of these problems in some regions. A growing number of farms are raising alternative species of shrimp have been bred to be more disease-resistant. Some farms are being located in areas that are not amidst fragile wetlands, and measures are being taken to reduce disease and pollution. The industry is making an effort to educate farmers about responsible practices, but until a global, science-based certification system comes into being that is capable of tracking the origins and providing a reliable eco-label for the product, consumers have little way of knowing how prawns were produced. This is why, for the time being, most organizations that publish reliable seafood guides warn seafood lovers to avoid buying shrimp.