Biodiversity Loss

Aquaculture poses significant threats to biodiversity.

One crucial issue is the widespread introduction of non-native and genetically engineered species into aquatic environments. Farmed fish often escape, compete with native fauna, alter local ecosystems, and interbreed with wild species, leading to genetic degradation and reduced reproductive success. Industrial fish farming – particularly open-ocean systems – intensifies these impacts by enabling the free exchange of waste, pathogens, parasites, and chemicals between farms and surrounding waters. 

High-density aquaculture operations increase disease and parasite prevalence, requiring heavy use of antibiotics, pesticides, and other chemicals, which disrupt local microbial and macrofaunal communities. Waste from uneaten fish feed and feces accumulates in sediments, contributing to nutrient pollution, eutrophication, and algal blooms. This excess of nutrients reduces marine oxygen levels and kills seagrasses, corals, and fish. Plastic and toxic heavy metals used as antifoulants, including copper and zinc, also leach into aquatic ecosystems, harming marine life and human health through bioaccumulation. 

The growing demand for fishmeal and fish oil to feed farmed species places pressure on forage fish populations, destabilizing ocean food webs and reducing the availability of resources for wild species. Moreover, aquaculture infrastructure physically alters habitats, destroying critical coastal ecosystems. Marine mammals and birds attracted to a surplus of fish in and around farms but are often entangled, harmed, or killed. These cumulative effects contribute to a measurable decline in species richness, abundance, and ecological resilience, all indicators of biodiversity loss.