Aquaculture can have a significant impact on greenhouse gas(GHG) emissions, Nitrogen(N) and Carbon(C) that are not consumed in intensive aquaculture systems are converted to CH4 and N20 discharged yearly in megaton amounts. Mangroves, wetlands and energy requires for aquaculture operations like aeration, water circulation, and temperature control and the energy used for the production and transportation of feed for aquaculture species can result in CO2 emissions.

A study discovered that cultivating four different rice cultivars alongside fish in a lab setting resulted in reduced methane (CH4) and nitrous oxide(N2O) emissions than growing fish alone. In this experiment, five treatments involving fish co-culture with different rice cultivars(Jia 67, Xiushui 121, Yongyou 1540, Zhongzheyou 8) and a control with fish monoculture were tested. Each treatment had four replicates in 20 tanks measuring 1.75*1.23*1 meter filled with homogenized soil from an aquaculture pond, used for over 10 years and filled to a 20 cm depth in each tank. Rice seedlings were transplanted into the tanks at a spacing of 0.5*0,5 meters with the water level as they grew, reaching a maximum depth of 0.7 meters. Fish fingerlings, averaging 4.5 grams, were added at 80 fish per tank and fed twice daily, with 40% of the feed at 07:00 and 60% at 18:00.

Co-culturing rice with fish lowered methane (CH4) and nitrous oxide(N20) emissions when compared to fish monoculture. Emissions varied among rice cultivars due to differences in soil CH4 oxidation, plant-mediated CH4 transport, and N2O generation substrates. Hybrid rice cultivars had higher yields and lower yield-scaled crop water productivity(CWP) than inbred varieties. To reduce greenhouse gas emissions from aquaculture, choose or breed rice cultivars with high yields, low plant-mediated CH4 transport, and high nitrogen uptake.(Xie et. al. 2024).

The conclusion of this study is that the emissions linked with three farms varied greatly: Hanafy farm with 3.265 kg CO2e/kg fish and 50.917 tonnes CO2e/Season, Hashim farm with 2.259 kg CO2e/kg fish and 45.829 tonnes CO2e/Season and Aly Farm with 2.223 kg CO2e/kg fish and 38.864 tonnes CO2e/Season.(Fouda et. al. 2022).

To address this, the study suggests reducing fossil fuel use, improving feed efficiency, promoting biofloc technology, and integrating multi-trophic aquaculture systems to build climate-resilient sustainable aquaculture. (Huang et. al. 2024).

The ethical issue in the article involves utilitarianism ethical theory because it emphasizes the importance of outcomes. In this article, choosing rice cultivars rather than aquaculture produce lower greenhouse gas emissions resulting to better overall outcomes for the environment and society. Applying utilitarianism to the article’s topic, the business practice is unethical if it prioritises cultivars that produce more GHG because such actions generate additional harm by contributing to climate change.

From a utilitarian perspective, continuing to use high emission aquaculture is unethical because it does not maximize overall well-being. Businesses have an ethical obligation to consider the broader effects in their practice. A utilitarian approach would advocate developing rice cultivars with low emissions, as this would benefit the environment and promote sustainability. As John Stuart Mill stated,” actions are right in proportion as they tend to produce the reverse of happiness.( Shaw et. al. 1998).

Fouda, T., Elrayes, A. E., & Elhanafy, A. E. (2022). Carbon footprint estimation in Egyptian aquaculture farms.

Huang, M., Zhou, Y., Tian, H., Pan, S., Yang, X., Gao, Q., & Dong, S. (2024). Rapidly increased greenhouse gas emissions by Pacific white shrimp aquacultural intensification and potential solutions for mitigation in China. Aquaculture, 587, 740825.

Wang, C., Shi, X., Qi, Z., Xiao, Y., Zhao, J., Peng, S., & Chu, Q. (2023). How does rice-animal co-culture system affect rice yield and greenhouse gas? A meta-analysis. Plant and Soil, 493(1), 325-340.

Shaw, W. H. (1998). Moral issues in business.

Lofts, K., Shamin, S., Zaman, S. T., & Kibugi, R. (2017). Brief on Sustainable Development Goal 13 on taking action on climate change and its impacts: Contributions of international law, policy and governance. McGill J. Sust. Dev. L., 13, 183.

From a deontological perspective, the ethics of duty, the significant methane (CH4) and nitrous oxide (N2O) emissions from intensive aquaculture make the practice unethical. Under this ethical framework, emissions resulting from aquaculture must be viewed as harmful to the environment since they upset the ecological balance and contribute to the creation of an aquatic desert.

I also want to clarify that it is important to view harmful practices as unethical and to identify with an ethical system that respects both the value of nature and the environment, even in the face of an industry that seems dedicated to the opposite. For aquaculture to be considered ethical according to the ethics of duty, responsible practices must replace harmful practices, and emission reduction must be a focus of industry practices.( Shaw et. al. 1998).

This theory posits that for businesses, it is not sufficient to focus only on profits; they must also prioritize the well-being of the environment, employees, the local community, and shareholders. Neglecting environmental stewardship, it is suggested, may harm ecosystems and communities and can be seen as psychologically maladaptive and even unethical under the ethic of care. Swimming against the current can be harmful to both fish and fishing communities. For example, aquaculture practices that significantly contribute to greenhouse gas emissions seem to fall well short of the duty of care owed to the environment and all those (including current and future generations) who have a stake in its health and viability.( Shaw et. al. 1998).

The study conducted by Xie et al., titled "Effect of Rice Cultivar on Greenhouse-Gas Emissions from Rice-Fish Co-Culture," investigates how different types of rice affect the release of greenhouse gases (GHGs) in the process of co-cultivating fish and rice. As per the authors, this integrated farming system can be used as a substitute for conventional aquaculture and rice agriculture, both of which contribute significantly to the release of greenhouse gas emissions, particularly methane (CH4) and nitrous oxide (N2O). These powerful gases are a significant factor in causing climate change. The study is applicable not just to integrated farming systems but also to Sustainable Development Goal 13 (SDG 13). This objective pertains to implementing measures to mitigate the effects of climate change.
The study suggests that by choosing rice cultivars carefully, it is possible to decrease the quantities of specific emissions, like methane and nitrous oxide, that are produced by rice fields. The decrease in paddy emissions can significantly contribute to the worldwide efforts to mitigate climate change. This study's implications are most closely aligned with Goal 13, "Climate Action," as defined by the Sustainable Development Goals.
Furthermore, it emphasizes the importance of implementing innovative change in order to achieve sustainable agricultural development. This is essential not only for the conventional answers we have been considering, but also for taking action on climate change. Only the implementation of groundbreaking change will enable us to achieve the goal of limiting global warming to 1.5 degrees. (Lofts et. al. 2017).

This study will look at the ethical issues surrounding GHG emissions and co-culture rice cultivars techniques to minimize environmental degradation, using utilitarianism ethical theory, deontological theory and ethic of care to assess the balance between food production and environmental sustainability. SDG 13 (Climate Action) which address climate change and seeks to conserve ecosystems. The assignment will investigate the impact of intensive aquaculture on emissions and way to use co culture rice cultivars techniques, identify relatable ethic theory, and how sustainable practices contribute to achieving these UNSDGs.

The authors explained how the system of rice cultivation alongside animal species (such as ducks, fish, and frogs) affects the rice yield and the production of greenhouse gases (GHGs). It combines data from 247 studies to compare the results of rice grown in monoculture with rice grown in association with certain animal species. It finds that the co-culture system reduces emissions of the dangerous GHG methane (CH4)—a potent GHG that is produced in anaerobic (without oxygen) fermentation by some microorganisms—in half of the situations studied; and that it also increases the rice yield. In the study, the favorable results obtained with ducks were better than those obtained from fish, who were better than frogs, in conjunction with other animal companions, Ferner reports. One reason for the favorable results of co-culture, say Jiang and his colleagues, is that the animals may be stirring up the soil and, in doing so, may be helping to aerate it. (Wang et. al. 2023).