Derivation of economic values for important production traits in Atlantic salmon

Atlantic salmon breeding programs selected several traits simultaneously. Lack of economic values may lead to inappropriate relative weighting of the traits selected for and with a suboptimal long-term genetic gain of the traits. Derivation of reliable economic values for important traits in Atlantic salmon is therefore necessary to optimize the economic benefits of the breeding program. The objective of the thesis was to firstly to derive economic values for six important production traits of Atlantic salmon in the grow-out phase in seawater, and secondly to predict the genetic gain for each trait, and thirdly to calculate the relative contribution of each trait to the overall economic genetic gain. The studied traits were harvest body weight (HBW), feed conversion ratio (FCR), early sexual maturity (ESM), general mortality (GM), specific mortality (SP) and fillet yield (FY). Harvest body weight was modeled through the growth factor. The economic values for the traits were expressed as NOK/trait unit/kg round body weight produced. HBW was the most important trait with an economic value of 1.95 NOK/kg; followed by the correlated trait FCR with -11.8 NOK/kg feed, FY with 0.82 NOK/%-unit; GM with -0.26 NOK/%-unit; SM with -0.37 NOK/%-unit, and ESM with -0.22 NOK/%-unit. The magnitude of their contribution to the overall economic genetic gain was 48 % (HBW), 47 % (FCR), 5.3 % (FY), 0.9 % (GM), 0.1 % (SM) and -1.6 % (ESM). Given that records of feed intake could be obtained, the contribution of FCR to the overall genetic gain increased by 11 %- units while that of HBW decreased by 10 %-units. The overall economic genetic gain per generation was estimated to NOK 2.20 and NOK 2.45 per kg fish produced without and with feed intake records, respectively. This is the first reported study on the derivation of economic value for traits in Atlantic salmon. The predicted genetic gains for the studied traits and their relative contribution to the overall economic gain relies on reliable genetic parameters for the traits that are missing for most of the traits. Nevertheless, the results give some insight about the expected genetic gain of each trait their relative contribution to the overall economic gain.

I avlsprogrammer for atlantisk laks blir det selektert for flere egenskaper trekk samtidig. Mangel på økonomiske vekter kan føre til ugunstig relativ vekting av egenskapene og dermed med en ikke optimal langsiktig genetisk endring av egenskapene. Pålitelige økonomiske vekter for viktige egenskaper hos laks er derfor nødvendig for å optimalisere et avlsprogram. Målet med oppgaven var for det første å regne ut økonomiske verdier for seks viktige produksjonsegenskaper hos atlantisk laks i vekstfasen i sjøen, og for det andre å estimere den genetiske framgangen for hver egenskap, og for det tredje å beregne det relative bidraget av hver egenskap til den totale økonomiske framgangen for alle egenskapene. De studerte egenskapene var tilvekst fram til slakting (HBW), fôrutnytting (FCR), tidlig kjønnsmodning (ESM), generell dødelighet (GM), spesifikk dødelighet (SM) og filetutbytte (FY). Tilvekst ble modellert ved bruk av vekstfaktoren. De økonomiske verdiene for egenskapene ble uttrykt som NOK/enhet/kg produsert rund kroppsvekt.