In Japan, various species of edible fish whose genetic material has been engineered using new genetic engineering (or new new genomic techniques, NGTs) have already been introduced to the market. One example is red sea bream, in which the genes responsible for regulating muscle growth have been switched off. As a result, the fish show stronger muscle growth, a larger body circumference, a shorter body length and a misalignment of the vertebrae. In comparison to the wild type, the NGT-fish gain weight faster and appear to move more slowly (Kishimoto et al. 2018).

The aim of the NGT application is to increase the weight of fish. To this end, the myostatin gene has been blocked. This leads to excessive muscle growth, which can have significant consequences for animal health. Experiments to block or alter the function of myostatin using NGTs have already been carried out on cattle, buffalo, sheep, goats, pigs, rabbits, fish, poultry, horses and dogs (Testbiotech, 2025). This makes the myostatin gene probably the most common target gene in NGT farm animals. From an animal welfare perspective, this is not progress, but rather a new form of intensified exploitation.

Data on how the genetic alterations affects the overall lifespan and health of the NGT fish has not yet been published. These developments are primarily driven by commercial interests: it is claimed that feeding the fish in special containers reduces feed costs.

Furthermore, the scientists involved hold patents for NGT applications in fish. One company had taken over the marketing of the NGT fish via an internet portal. It is unclear whether the fish are actually still on the market.

This example shows: Applications of New Genetic Engineering techniques can result in plants and animals with extreme biological characteristics, which go beyond what can be achieved in conventional breeding. Without mandatory approval processes and a prospective technology assessment, more and more genetically engineered plants and animals may enter the market without having undergone detailed risk assessment; they may also have questionable traits from an ethical perspective. It would mean paving the way for ‘progress’ to go in the wrong direction – with serious consequences for humans, animals and the environment.

Publication year: 
2021 (updated in 2025)

Further information: 

Kishimoto et al. (2018): Production of a breed of red sea bream Pagrus major with an increase of skeletal muscle mass and reduced body length by genome editing with CRISPR/Cas9.

Testbiotech (2025): Use of new genetic engineering in farmed vertebrates: a critical assessment.

Testbiotech news (2021): CRISPR fish: suspected ‘torture’ breeding