How stocking density management in tilapia aquaculture affects fish welfare and what better practices look like for this globally important species.
Tilapia welfare has historically received less research attention than salmon welfare, despite tilapia being the second most farmed fish in the world. The species is often characterised as hardy and stress-tolerant in ways that have rationalised poor welfare conditions, but research shows that tilapia at high stocking densities show measurable welfare deterioration including elevated stress physiology, increased aggression, and impaired immune function. The sex reversal treatment used to produce all-male monocultures also raises welfare concerns from the high-dose hormonal treatment used. Improving tilapia welfare at the scale of global production would benefit enormous numbers of individual fish and is achievable through density management and better production system design.