From our production in Iceland, we can offer ova selected specifically for high growth and significant reduction in early maturation (All-Female), or even completely elimination of early maturation (All-Female/Trilploid). This selection is made with the emerging land-based RAS production sites in mind. These production systems are experiencing less disease challenges, although early maturation of males is still an issue to address.
This is where SalmoRAS4+ makes a difference in optimizing the production cycle on land. The product is also available with QTL-IPN for protection against outbreaks of Infectious Pancreas Disease.
Preventing early maturation
- No feeding of the broodfish during the last months of production
- Only certified organic feed is permitted the last 6 months ahead of stripping
- Broodstock tanks for organic production must have separated water systems to completely separate the fish from regular production
- Hormones to induce spawning is not permitted for organic broodstock
- Special requirements for what type of disinfectants to be used for cleaning the tanks and the equipment
- Fish tanks, incubators and packaging is specifically marked with the certifier’s signage
Early sexual maturation is a common problem in high-intensity production systems, such as land-based RAS facilities. When the fish goes into maturation, it stops growing and converts muscle and fat into testes and ovaries.
Benchmark Genetics has been selecting for late sexual maturation in the breeding programs since the early 1970s; starting with phenotypic selection, moving into family selection in 1991 and further introducing Genomic Selection (GS) in 2017.
At our facilities in Iceland, we have also been introducing specific treatments of broodstock and eggs, resulting in a significant reduction in sexual maturation; All-Female and triploid. These products are now gaining increased popularity with land-based customers, as they are experiencing improved production output and profitability by greatly reducing the rates of early maturation.
The All-Female method is a complex breeding strategy where female broodstock is sex-reversed in a process called masculinization, using hormones. These males produce sperm cells that all carry X-chromosomes giving offspring populations that only consist of females, resulting in the “All-Female” product. As females have a much lower incidence of early maturation, this significantly reduces the early maturity challenge that many land-based farms are experiencing with mixed-sex populations. The All-Female product has become very popular with full-cycle land-based customers, who experience a higher number of individuals fully grown to the ideal harvest weight and more homogeneous weight distribution.
Some producers, using combinations of high temperature and full-cycle freshwater, are still experiencing 12–15% losses on All-female due to maturation. It is possible to eliminate the problem by letting the All-Female eggs go through a process called Triploidization. Triploid salmon carry three sets of chromosomes instead of two, are sterile and never mature. Triploids occur naturally at low levels in all plants and animals and are commonly used in crop production (e.g., tomatoes) and aquaculture (e.g., oysters). In salmon, triploidy can be induced by exposing eggs to pressure shortly after fertilization. Although the number of chromosomes is increased through this reproductive technique, no genetic modification is involved, and triploid crops and animals are not GMO. Triploid salmon is slightly more sensitive to temperature during incubation and low oxygen levels during growth. Nutritional requirements are also slightly different.
Contact our technical staff for more information.
Read more about our selection for land-based farming in our brochure.