Aquaculture can be environmentally sustainable
Aquaculture can be implemented in many forms at varying scales. Marine organisms can be raised in ponds, raceways, man-made inland systems, or open ocean pens. The scale of aquaculture systems can vary from ‘backyard fish farming’ in a family pond to a vertically integrated operation that produces thousands of tonnes from a single site. These scales of operation can be separated by a variety of criteria, including the goal(s) of production or the operating sustainability level.
Aquaculture is a sustainable way of meeting the global seafood demands and is only improving in overall efficiency as time progresses. However, there are a number of impediments that burden the development of aquaculture in the United States. The largest impediment to aquaculture in the US is the regulatory burden. According to the Reason Foundation, regulatory barriers at the federal and state level have impeded open ocean aquaculture into further expansion for sometime.
Another key impediment that has burdened offshore aquaculture development is the high related cost. However, the narrative of failing to realize the economic viability of open ocean aquaculture in the Americas and the Caribbean is gradually changing. For instance, the traditional pen systems with lower capital and operating costs in ideal environments or locations, which are typically in developing Latin American countries, may be able to offset the high production costs needed to produce cobia in more developed countries.
It is not a false claim that offshore aquaculture could cause impacts to its surrounding environment. However, this can be and has been resolved through proper planning, management, and siting. Open ocean aquaculture operations can produce commercial quantities of high-quality seafood without causing significant environmental impact. The offshore aquaculture of cobia in Puerto Rico and the Bahamas has not found any cumulative impact in the water column or at the seafloor bottom around the farming sites when environmental monitoring has been conducted. Furthermore, uneaten feed and fish discharge from net pens are organic material which can be degraded and utilized by surrounding aquatic ecosystems.
Land agriculture has capitalized on cultivating certain species over time that are considered easier or more efficient in terms of raising them. Likewise, there are certain species for aquaculture that can be raised more efficiently than others while also minimizing environmental footprint. Recirculating aquaculture systems (RAS) are closed-loop systems that can intensively recycle water and resources. RAS offers a high degree of control over environmental variables, varying levels of biosecurity, as well as, waste treatment. Some marine species are more suited for this type of system versus others. It can be noted that RAS systems boast the ability of being located closer to consumer markets – nearly anywhere inland from the coasts. This aspect can resolve the costal access or requirement barrier that has impeded US aquaculture expansion.
Aquaponics is another system that can reduce the environmental footprint of aquaculture operations. Similar to RAS, it contains the basic components of a recirculating system. However, the bioﬁlter has been replaced by plants that assimilate the nitrogenous waste products and then turn them into saleable plant products. This is an additional method of turning fish wastes into nutrients to nourish and grow plants while mitigating the common discharge issue. Aquaponics can be applied in or near urban areas to grow fresh fish and vegetables simultaneously, ultimately providing surrounding areas with fresh and healthy foods through sustainable techniques and minimal required space.
Sustainable aquaculture measures:
There are measures to minimize the environmental impacts of aquaculture. A priority is to ensure constant sustainable sourcing of feed. Improving feeding techniques and innovative feed formulations can aid in this process. Furthermore, to reduce the stress on wild fish stocks (usage of fishmeal and fish oil), substitution sources can be applied such as soybeans or other crops grown.
Another known issue to offshore aquaculture is the potential instance of escapees. Over time, technical standards and improved equipment have been adopted to reduce or eliminate this issue. For example, copper or brass netting is commonly used for both its industrial strength against varying weather conditions and its natural element to ward off predators. Many pens have become fully submersible to be dropped during harsh storms which prevents instances of damage to pens and potential release of finfish. Another solution is closed containment systems which are used in salmon open ocean aquaculture. These aid in alleviating or eliminating most issues caused by open ocean pen farming, including instances of escapees, the spread of diseases, and sea lice. Adoption of these techniques and solutions significantly reduces the impact of farming fish in relation to wild species.
“If we can shift production toward the most sustainable forms of aquaculture production, we can not only foster healthier marine ecosystems, but also a stronger global food system.“The Nature Conservancy
The benefits of aquaculture to habitats and humans:
Aquaculture is a tool to produce fish, shellfish, plants and corals in the hatchery to grow wild fish stocks and rebuild threatened and endangered species in habitats.
Some extractive species, such as mussels, sea cucumbers, worms and various seaweeds, are being grown through aquaculture systems. These species can improve their surrounding ecosystems and be beneficial in a variety of ways. Integrated multitrophic aquaculture (IMTA) applied to aquaculture combines the cultivation of fed aquaculture species (e.g., salmon) with extractive aquaculture species (e.g., shellfish and kelp) to mimic the conditions of a balanced ecosystem at a farm site. Extractive species use the organic and inorganic materials and by-products from the other species to power their own growth. For example, oysters can clean the water they live in by using the waste and nutrients from other animals as food for their growth. Seaweed and other underwater vegetation take in carbon through photosynthesis and improve the quality of surrounding water. IMTA not only benefits the environment but is also able to generate economic and social benefits such as creating diversified products and partnerships with local indigenous people who were perhaps unwilling to support conventional aquaculture methods. Harnessing the potential of commercial marine aquaculture can accelerate coastal ecosystem restoration, as well. This practice is commonly referred to as Restorative Aquaculture. An example of this technique can include people gaining water quality benefits from shellfish farms in the Chesapeake Bay. Aquaculture can also be used for treating sewage and wastewater in some cases. In India, the treated sewage passes through ponds of duckweed, prawns, and carp successively. These organisms clean the water by extracting nutrients from the waste, so the water can be used for agricultural purposes afterward.
Aquaculture can produce food in a responsible manner without causing extensive environmental impacts. Moreover, aquaculture is beneficial to habitats and humans in numerous ways. Endangered or threatened species can be protected and assisted by restoring stock numbers through restocking management. The FAO states that United States began stocking fish into streams and channels before the 1900s. The first species stocked were channel catfish and trout. Today, various types of species are being stocked through aquaculture methods including bait fish, salmon, walleye, halibut, and more.
“Marine aquaculture in the United States contributes to seafood supply, supports commercial fisheries, restores habitat and at-risk species, and maintains economic activity in coastal communities and at working waterfronts in every coastal state.”NOAA
- Farming the Oceans: Opportunities and Regulatory Challenges for U.S. Marine Aquaculture Development
- Growth rates of cobia cultured in open ocean submerged cages in the Caribbean
- Disparities in obesity prevalence due to variation in the retail food environment: three testable hypotheses
- Restorative Aquaculture for Nature and Communities
- Sewage-fed aquaculture: a sustainable approach for wastewater treatment and reuse
- Marine Aquaculture Impacts on Marine Biota in Oligotrophic Environments of the Mediterranean Sea – A Review
- Aquaculture Production Systems
- Valuing the Willingness-to-Pay for Sustainable Seafood: Integrated Multitrophic versus Closed Containment Aquaculture
- National Aquaculture Sector Overview – United States of America
- 35-150 billion fish are raised in captivity to be released into the wild every year