# Comprehensive Assessment and Trading Mechanism of Carbon Sink in China’s Marine Aquaculture

## TL;DR

This study evaluates China's marine aquaculture as a carbon sink from 2004 to 2023 and proposes a trading mechanism to monetize its carbon sequestration potential.

## Contribution

The study introduces a species-specific assessment model and a proposed carbon sink trading mechanism for marine aquaculture in China.

## Key findings

- Cumulative carbon sink in marine aquaculture reached 46.3618 million tonnes from 2004 to 2023.
- Shellfish contributed 45% of the total carbon sequestration, followed by shrimp at 24%.
- A trading mechanism could provide economic incentives for sustainable aquaculture practices.

## Abstract

This study assesses China’s marine aquaculture as a carbon sink over the period 2004–2023. By analyzing five key cultured groups—shellfish, shrimp, fish, crabs, and algae—we quantified regional carbon sinks and delineated each group’s contribution. Results show that total carbon sink capacity more than doubled during this period, with shellfish alone contributing almost half (45%) of the cumulative sequestration. Different provinces exhibited distinct trends, some relying primarily on shellfish farming, others on shrimp or mixed aquaculture systems. To translate these ecological gains into practice, we propose a dedicated carbon sink trading mechanism. Our analysis indicates that this mechanism could provide additional income to aquaculture operators and incentivize sustainable practices, thereby enhancing marine habitat quality and advancing China’s climate objectives.

This study develops species-specific assessment models for carbon sink in marine aquaculture (CSMA) using provincial data from China’s coastal regions (2004–2023). Key findings are as follows: (1) Cumulative CSMA reached 46.3618 million tonnes, exhibiting three growth phases—initial fluctuations (2004–2008), rapid growth (2008–2015), and optimization and maturation (2015–2023). (2) Species contributions were heterogeneous: shellfish dominated at 45%, followed by shrimp (24%), fish (15%), crab (11%), and algae (5%). (3) Spatially, Guangdong, Fujian, and Shandong consistently lead in CSMA; Guangxi, Liaoning, and Zhejiang form a second tier, whereas Hebei, Hainan, and Jiangsu remain at the lower end. (4) Province-specific dominance patterns were observed: shellfish-dominant pattern in Shandong, Fujian, and Liaoning; shrimp-dominant pattern in Hebei and Hainan; shellfish-and-shrimp dual-cores in Guangdong and Guangxi; and a multifaceted profile in Jiangsu and Zhejiang. To facilitate the realization of CSMA’s value, we propose a dedicated trading mechanism. Based on the derivations from the effect analysis model and the illustrative case studies, we explore the potential economic and ecological benefits of CSMA trading.