Figure 1.
Location of wild salmon populations and the Matre research station.
Wild salmon populations of four Norwegian rivers were included in the present study conducted at the Matre research station. Parental salmon were collected directly from the rivers, except for salmon of the River Skibotn strain that is conserved and reared in freshwater at the Norwegian Gene Bank for Atlantic salmon.
Table 1.
Weight and length measurements of parental salmon of cohort 2011, 2012 and 2013.
Figure 2.
Egg size in relation to maternal body size.
The effect of maternal body size upon mean egg sizes in salmon of farmed and wild origin, illustrated by the regression plot between mean egg sizes (mm in diameter) and maternal body weight (grams). Dotted lines illustrate the 95% confidence interval. For model selection of the linear model investigating the relationship between maternal log-weight and egg diameter, see File S1.
Figure 3.
Mean cumulative degree-days from fertilisation to percentage hatch in the; A) Figgjo/Mowi cross C2011, B) Figgjo/Mowi cross C2012, C) Figgjo/Mowi cross C2013, D) Vosso/SalmoBreed cross C2013, E) wild strains C2012, and F) wild strains C2013. See Table 3, 4 and File S2 for the adjoining statistical results.
Table 2.
Number, egg size, cumulative degree-days to hatch and total length prior to the onset of exogenous feeding in salmon of farmed, hybrid and wild origin of C2011, C2012 and C2013.
Table 3.
Significance levels of random and fixed effects included in the full linear mixed effect models (model 2) investigating variation in cumulative log degree-days from fertilisation to hatch in salmon of farmed, hybrid and wild origin of C2011, C2012 and C2013.
Table 4.
P-values of the parameter level tests of the final LME models (model 2) investigating strain difference in time of hatch in salmon of farmed, hybrid and wild origin of C2011, C2012 and C2013.
Figure 4.
Egg size and alevin length prior to the onset of exogenous feeding in wild/farmed crosses.
A) Figgjo/Mowi cross C2011, B) Figgjo/Mowi cross C2012, C) Figgjo/Mowi cross C2013 and D) Vosso/SalmoBreed cross C2013. DD: degree-days from fertilisation to termination prior to the onset of exogenous feeding. Families are sorted in groups containing their respective maternal and paternal half-sibling, i.e., three families per group in Figure A and D, and four families per groups in Figure B and C. Wild/farmed hybrids are named by the origin of their maternal × paternal half-siblings. Maternal half-siblings emerging from farmed eggs are illustrated by dotted lines, while maternal half-siblings emerging from wild eggs are illustrated by solid lines. In C2011, F1 hybrid family 4 and 6 are paternal half-siblings to Figgjo family 22, while F1 hybrid family 8 and 10 are paternal half-siblings to Figgjo family 23. In addition, Figgjo family 26 and 27 is paternal half-siblings to F1 hybrid family 14. Boxes show the median (thick line), mean (+), 1st and 3rd quartiles (lower and upper boundary) and the lower and upper extreme (whiskers). See Table 5 for the adjoining statistical results.
Figure 5.
Egg size and alevin length prior to the onset of exogenous feeding in wild strains.
A) C2012 and B) C2013. DD: degree days from fertilisation until termination. Strains are sorted by cumulative degree day from fertilisation to termination prior to the onset of exogenous feeding, while families within each strain are sorted by their length, both in increasing order. Maternal half-siblings are illustrated by solid lines. In C2013, Skibotn family 9 and 11, and 19 and 12 are paternal half-siblings. Boxes show the median (thick line), mean (+), 1st and 3rd quartiles (lower and upper boundary) and the lower and upper extreme (whiskers). See Table 5 and File S2 for the adjoining statistical results.
Table 5.
Significance levels of random and fixed effects included in the full linear mixed effect models (model 3) investigating variation in total length prior to the onset of exogenous feeding in salmon of farmed, hybrid and wild origin of C2011, C2012 and C2013.
Figure 6.
Growth of Norwegian Atlantic salmon prior to and post the onset of exogenous feeding.
Additive genetic variation for growth is well documented in Norwegian Atlantic salmon of farmed, hybrid and wild origin, and farmed salmon outgrow wild salmon extensively at the smolt stage under hatchery conditions. However, this study demonstrates that ten generations of directional selection for increased growth has not resulted in significant differences in growth rate prior to the onset of exogenous feeding between farmed Norwegian salmon and its wild conspecifics. This figure is based upon observed growth measurements of the farmed Mowi strain, the wild Figgjo strain and their F1 hybrid strain of C2011 [18].