Fish hatchery raceways

Raceways are rectangular channels with continuous water flow used in intensive fish farming to rear fish at high densities with precise environmental control.

About this subject

Raceways are intensive fish farming systems consisting of long, narrow channels, typically made of concrete or fiberglass, through which water flows continuously. Originating in the United States for rainbow trout culture in the 1950s, these tanks allow high stocking densities, ranging from 30 to 50 kg per cubic meter depending on species and dissolved oxygen levels. In Brazil, they are widely used for Nile tilapia, especially in regions with good water availability such as the South and Southeast. Water flow, usually 6 to 10 centimeters per second, replenishes oxygen and removes metabolic wastes, but requires supplemental aeration at high loads. The rectangular shape facilitates automated feeding, fish grading, and harvesting. Despite high productivity per unit area, the system demands rigorous water quality management, with constant monitoring of ammonia and nitrite, as well as effluent treatment to prevent environmental impacts.

Frequently Asked Questions

Which species are most commonly raised in raceways?

The most common species are rainbow trout, Nile tilapia, Atlantic salmon, and some catfish. The choice depends on water temperature and local market demand.

What is the ideal stocking density in raceways?

Stocking density ranges from 30 to 50 kg/m³ for trout and tilapia, and can reach 80 kg/m³ in systems with aeration and pure oxygen. The limit is determined by the system's carrying capacity.

How is water quality control carried out in raceways?

Control involves daily measurements of dissolved oxygen, temperature, pH, ammonia, and nitrite. Aerators, partial water exchanges, and in recirculating systems, biofilters are used to remove toxic compounds.