Rainbow trout (Oncorhynchus mykiss) adaptation to a warmer climate: the performance of an improved strain under farm conditions

CRICHIGNO, SONIA ALEJANDRA; CUSSAC, VÍCTOR E.

AQUACULTURE INTERNATIONAL

SPRINGER

Lugar: Berlin; Año: 2019 p. 1 - 14

0967-6120

The change registered in water temperature over recent years has represented a considerablechallenge for the culture of salmonid fishes in terms of thermal stress. However, previous trialswith Australian, Japanese, and Argentinean rainbow trout lines suggested that improvementsin thermal performance might be possible. The aim of this work was to explore performance,i.e., the survival, malformations, food intake, growth, feed conversion efficiency, conditionfactor, thermal tolerance, and preferred temperature of a number of F1 families (wild thermalresistant male × farmed female) in order to formulate proposals for future work. The performancesevaluated showed significant differences between F1 and control families, but nomajor heterogeneity within F1 families. The incidence of complex malformations, lower in F1families than in controls, could indicate an advantage due to lower homozygosity. Thermaltolerance varied within F1 families but preferred temperature did not. Survival data suggestedthat chronic exposure to 20.5 °C had a lethal effect on control families. However, F1 familiesacclimated to 20.5 °C over a long period of time (ca. 109 days) preferred a mean temperatureof 20.2 ± 0.2 °C, a final temperature preference substantially higher than those observed forother populations and strains of the species. Although growth differences between control andF1 families should be considered with caution, since no family was selected by growth in thiswork, it appears that simple selection by growth could be all that is necessary before beginningthe process of introducing these families into farmed lines.