As mariculture—the cultivation of aquatic organisms in marine environment—intensifies to meet the demands of sustainable blue growth and national policies, novel ethical challenges will arise. In the context of ethics, primary concerns over aquaculture and mariculture tend to stay within differing value-based perspectives focused on benefits to human and non-human subjects, specifically animal welfare and animal rights. Nonetheless, the burgeoning field of feminist blue humanities provides ethical considerations that extend beyond animal subjects (including humans), often because of its concerns with new materialist, posthumanist, and other relations-based theories. This article examines feminist blue humanities and the contributions it may bring to understanding contemporary and future ethical challenges posed by mariculture and its intensification, especially the cultivation of low-trophic organisms. By offering an overview of feminist blue humanities, this article explores some of its particularities by drawing out three major ethical concerns facing contemporary mariculture, specifically material reconfigurations, radical alteration of the lives of low-trophic species through industrialization and increases in maricultural waste products.