When it comes to helping restore ecosystems, we tend to think about using fewer resources to better protect and preserve that system. With the example of fish that have been overfished, this means harvesting fewer (or even no) fish, in order to ensure that some fish remain and reproduce so that we can continue to have them in the future.
We often think of the food production industry as harming the environment and in fact, it is responsible for around 33% of global greenhouse gas emissions [1]. However, as we head into the future, what if we could design aquaculture to actively help the environment? For the most part, advancements in industry have been harmful to the natural environment in some way. We’ve gotten so used to this idea for so long that we have begun to view it as unavoidable, but the human mind is capable of nearly anything it can think of, if it really wants to put the effort in.
As the need for food production grows, along with an increase in environmental awareness, there is increasing evidence that we humans are finally pulling our brains in a new direction—one that is challenging our past assumption that increasing food production must lead to the degradation of the environment.
This is particularly relevant to us here in Maryland, as this concept utilizes seaweed and, you guessed it, oysters (or more broadly, bivalve shellfish)! In fact, Maryland’s Eastern Shore has been practicing restorative aquaculture for decades. Now we finally get to the definition of this month’s title; restorative aquaculture is when it actively benefits the environment, with the potential to generate positive environmental outcomes.
Oysters, as many of us know, are filter feeders which means the very act of them living and feeding cleans the water of excess nutrients and pollution. Furthermore, farming shellfish and seaweed require what is called “near-zero input”. Basically, this means that their aquaculture production requires almost no extra inputs including food, water, or land. In fact, oyster farming has officially been recognized as an effective water quality improvement strategy to help manage nitrogen levels in estuaries throughout the US [2].
While we might be familiar with oysters, the question becomes, how does restorative aquaculture actually work? Restorative aquaculture is typically focused on cultivating more than just a single species. If a farm raises oysters alongside fish, the oysters will help remove the excess nitrogen produced by the fish, meaning you can avoid having to spend thousands of dollars getting the nitrogen removed through wastewater treatment, a treatment which is necessary to maintain the health of fish.
Adding more species can do even more. Seaweed is excellent at controlling the amount of carbon dioxide in the water, and these aquatic plants provide habitat and shelter from predators for animals like blue crabs, conch, and even lobster during their early stages of life.
Both small-scale and commercial aquaculture can have a notable impact on the environment. There is no size requirement to be a restorative aquaculture farm. To be considered restorative aquaculture, there are six principles that must be met. We won’t go into depth with all of them here, but one of six, listed last yet crucially, is that “the socio-economic value of the environmental benefits provided are recognized” [3]. In short, restorative aquaculture must be recognized as not just environmentally positive, but economically and socially good for humans; a process that benefits all.
The most heartening thing about restorative aquaculture is the projected but as of yet untapped potential. As we look to the future of a growing global population, restorative aquaculture holds the hope that we will have a way to produce more food and more jobs with less environmental impact than we have now.
References:
[1] https://news.un.org/en/story/2021/03/1086822
[2] https://nerrssciencecollaborative.org/resource/oysters-and-nitrogen-removal-graphic