Paracas Bay on the coast of Peru is an area which is a part of the Paracas National Reserve as well as an important area for fishing and fisheries-related factories. Harmful algal blooms often cause hypoxia in Paracas Bay as a result of algal respiration and decomposition. A devastating bloom of the dinoflagellate Gymnodinium sanguineum occurred in 2004 and caused anoxia, which together with toxins produced by algal blooms resulted in massive fish and shellfish deaths.The massive fish deaths and closing of the port caused huge economic losses for fish industry and aquaculture.

It has been concluded that the 2004 mass mortality of benthic species was partly caused by untreated waste from the fish meal factories.