In a previous article, we examined the water pollution caused by fish farming. In today’s post, we will examine the pollution caused by one of Asia’s top delicacies, Abalone. I would be sharing the findings from Kang et al. (2016) research on Abalone farms in Wando, South Korea.
Shellfish aquaculture is generally seen as having a mild impact or even being beneficial to water quality. This is because shellfish are filter feeders that reduce the concentration of nutrients, and phytoplankton and improve the clarity of the water. However, the effluents from cage cultures in fish farms, mainly uneaten food and primary faecal and urinary products, are released directly into the surrounding environment (Kang et al., 2016).
In Kang et al. (2016), they found that the Total Nitrogen (TN) levels in sediments near Abalone farms are around 0.25%, significantly higher than most fish farms which have a TN level of around 0.1%. The increase in Nitrogen is due to the use of seaweed as feed for abalone. The increase in Nitrogen levels results in worsen eutrophication and algae blooms in the surrounding water.
Furthermore, the sediments of near abalone farms have an average pH of 7.23, which is more acidic than normal seawater that has a pH of 8.16-8.20 (Kang et al., 2016). This acidification is attributed to the large amount of organic waste deposited from the farm resulting in sulfate reduction (Kang et al., 2016). Worse of all, pH levels have gradually decreased as the number and intensity of abalone farming increased. The acidification of the seawater could result in delayed embryonic development, decrease fertilization and an increase in mortality (Kang et al., 2016).
The sludge discharged from the abalone farms has also increased the concentration of heavy metals in the surrounding seawater. From 2002 to 2004, there was a rapid increase in Ni, Pb, Cu, CO, AS and Cd, corresponding to a dramatic increase in abalone production in the region (Kang et al., 2016).
Were you surprised to learn that abalone, a shellfish is also contributing to water pollution? Is there other food stuff you are interested to learn about? Share with me your thoughts.
References
Kang, J., Lee, Y. G., Jeong, D. U., Lee, J. S., Choi, Y. H., & Shin, Y. K. (2016). Effect of abalone farming on sediment geochemistry in the shallow sea near wando, south korea. Ocean Science Journal, 50(4), 669-682. https://doi.org/10.1007/s12601-015-0061-x
Featured image from https://medium.com/wwfhk-e/korean-abalone-farming-a-better-future-41abb7240ceb
