Mariculture | marine aquaculture | ocean farming | sea farming | marine farming | sea aquaculture | ocean aquaculture

Mariculture/sea farming/ocean farming should not be confused with aquiculture, which involves culture in fresh or brackish water.

Development of Mariculture (sea farming):

Mariculture started by catching wild juveniles and feeding them in a controlled environment. As more knowledge was gained, the degree of control with the production process increased and the farmers increased their influence on growth and reproduction.

Types of mariculture by activity intensity:

The degree of control of the production process is often categorized by the intensity of the farming operation. Four main activity intensity classifications are recognised: traditional, extensive, semi-intensive, and intensive mariculture (Quentin et al., 2010). 

Traditional and extensive mariculture:

Simplest form of culture involving protection of the stock to improve survival rates of wild juveniles, where no fertilizer or supplementary feed is added and the production from the pond depends entirely on the primary production. The primary production in turn depends on sunlight and nutrients available in the water and soil. Since nutrients are not fed into the culture, the stocking density and recurrent costs will therefore have to be low. In the case of mullets, milkfish and other herbivores or penaeids it is essential that the water level be maintained between 35 and 40cm in the general platform area of the pond to encourage algal growth on the pond bottom for the organisms to feed upon. If the water is deeper, the light intensity that reaches the bottom will not suffice to promote algal growth. 

 An example of an extensive method of mariculture used around the globe is mussel farming, whereby the farmer provides a rope or a stake for the juveniles to attach to and does some culling so that the density does not get too high, but actually leaves the mussels to grow without further interference.

 Semi-Intensive mariculture:

A form of sea culture involving increased production by stocking at a slightly higher density and adding fertilizers (organic or inorganic) to increase primary production within the pond and in turn increase the harvest from the pond. 

Intensive mariculture:

A form of mariculture involving higher stocking rates, increased depth of water (>40cm depth), increased supplementary feed with or without the use of fertilizers. Water depth in the rearing structure is greater than in the former sea farming types because the food for the cultivated organisms is not dependent entirely on primary production within the pond. 

Mariculture farming environments 

Below is a list of  7 sea farming / mariculture structures and culture systems:

1. Marine ponds: ponds to grow prawns and some finfishes either by tide-fed systems or by pumping in seawater at periodic intervals into it.
2. Tanks (broodstock, larval, grow out culture tanks): well-aerated tanks with regular exchange of water to keep the dissolved oxygen levels high and remove wastes.
3. Marine sea cage / floating cage: High density, low volume system with maximum production in unit area than in any other culture systems, often used to farm salmons, breams, snapper, seabass, grouper
4. Integrated multitrophic aquaculture (IMTA) and polyculture: Polyculture and integrated aquaculture are methods of raising diverse organisms within the same farming system, where each species utilizes a distinct niche and distinct resources within the farming complex.
   Recirculating aquaculture systems (RAS): closed and low discharge systems which have concerns for water conservation and reduced waste discharges.
5. Long line farming of bivalves: a non-fed culture system for bivalves.
6. Marine raceway: large concrete tanks having higher flow rates than ponds are raceways which are used for farming of many fish species.
7. Marine hatcheries: land-based seed production units set up in a protected environment to effect artificial reproduction.