Color accounts for the physical differences between salmon, that is, a trait that is noticeable by the public. Growth rate has been shown to vary among fish species. In particular, growth rate is indeterminate when discussing salmon. The idea that an increase in growth rate could yield a substantial increased yield in the farming of salmon, has opened doors to new scientific investigation. Chromosomes are yet another way that make salmon unique.
Chromosomes vary in number within the same species, making genetic variability certain.
Sexual determination and the sex ratio are important concepts while discussing female and male populations. These issues lead to the discussion of problems associated with genetics. Inbreeding causes salmon with various genes, to come into close contact with one another, and perhaps perpetuate mating between similar generations. This mating can cause a loss of genetic diversity. The second problem occurs with hybridization.