The growing global population requires reliable sources of food, and aquatic farming has become a significant method for meeting this demand. The cultivation of aquatic organisms is recognized as a necessary means of enhancing food security worldwide. However, the terms “aquaculture” and “mariculture” are often used interchangeably, leading to confusion about their precise meanings. Understanding the distinction between these two practices is important for discussing the future of food production. This article clarifies the technical differences between these two forms of aquatic cultivation.
Defining the Umbrella: Aquaculture
Aquaculture is the comprehensive term for the farming of aquatic organisms, including fish, mollusks, crustaceans, and aquatic plants. This practice involves intervention in the rearing process to enhance production, such as regular stocking, feeding, or protection from predators. It is broadly defined by the controlled or semi-natural conditions under which aquatic populations are cultivated.
The scope of aquaculture is extensive, covering all types of water bodies across the globe. This includes systems operating in freshwater, brackish water, and high-salinity marine water. Common methods include inland ponds, tanks, and advanced recirculating aquaculture systems (RAS). Species like carp, tilapia, and catfish are commonly raised in these diverse settings.
The Specific Focus: Mariculture
Mariculture is a specialized subset of aquaculture defined by the environment in which it operates. It involves the cultivation of marine organisms exclusively in saltwater habitats. This practice is sometimes referred to as marine farming.
Mariculture locations vary widely, including sheltered coastal zones, open ocean areas, and land-based facilities. These diverse locations are unified by the use of seawater, or water with a high degree of salinity. The organisms cultivated must be saltwater species, such as marine finfish, shellfish, or seaweeds, which thrive in high-salinity environments.
The Core Distinction: Water Type and Scope
The fundamental difference between the two terms rests entirely on the salinity of the water source used for cultivation. Aquaculture serves as the overarching term, encompassing all aquatic farming, regardless of salt content. Mariculture is limited to marine environments, where salinity levels are high, typically exceeding 30 parts per thousand (ppt).
This relationship establishes a clear hierarchy: every mariculture operation is a form of aquaculture, but the reverse is not true. Freshwater aquaculture (FA) is the other major branch, often conducted in water with a salinity of less than 0.5 ppt. Brackish water aquaculture, which utilizes a moderate mix of fresh and saltwater (between 0.5 and 30 ppt), is also encompassed under the broader umbrella. The distinction is based on environment, with mariculture being the marine-specific component.
Practical Application: Operational Environments and Species
The operational environments and the species cultivated provide tangible evidence of this distinction. Freshwater aquaculture operations are typically situated inland, utilizing man-made ponds or tanks. The focus is on species that require low-salinity water to thrive.
Mariculture, in contrast, focuses on open-water installations or land-based systems that require a constant supply of seawater. Marine species are cultivated using specialized methods:
- Oysters, clams, and mussels are cultivated using longlines or rafts suspended in coastal waters.
- High-value marine finfish, like Atlantic salmon, are commonly grown in large offshore net pens or sea cages.
- The cultivation of marine algae, or seaweed, also falls under mariculture, often using similar open-water systems.