Short abstract:

This paper discusses the concept of metabolism in reshaping more-than-human relationships in the context of the ocean, focusing on biomaterials derived from discarded oyster shells in Japan.

Long abstract:

Metabolic ideas have the potential to change how we conceptualise material entities as they reshape, circulate, and transform the social life of humans and nonhumans in the Anthropocene. Marx classically described the “metabolic rift” as the alienation of life that takes place with the input and output of energy, chemical reactions, nutrient cycling, biochemical processes, and the exchange of matter.

In this paper, I will explore the concept of the “metabolic” within the ocean context, with a specific focus on two ethnographic case studies involving biomaterials derived from discarded oyster shells in Japan: discarded oyster shells that undergo transformation into poultry feed and agricultural and aquaculture lime fertilizer, promoting microorganism activation both in soil and sea; and oyster larvae collectors made from powdered oyster shells and magnesium hydroxide, a byproduct of salt production.

These modes of circular production establish an optimal environment for shellfish larval attachment and survival, responding to ecological threats such as overfishing, red tide, and land reclamation in clam habitats. As oyster larvae settle and grow on the collectors, what biosocial assemblage emerges? Examining the material transformations of human and nonhuman worlds in their engagement with the seas and inhabitants, I delve into how biomaterial production, circulation, and consumption influence the outcome of the metabolic rift – the impact of a capitalist mode of industrial production that disrupts human–nature relationships.