in goldfish larvae raised at 13 °C compared 22 °C (Wiegand et al., 1991). A similar response to cold acclimation occurred in muscle lipids of adult eelpout, but liver 18:1(n-9) doubled at 0 °C compared to 6 °C (Brodte et al., 2008). Lake whitefish showed a general trend to retain 18:1(n-9c) throughout development, with higher levels at 1.8 °C compared to 8.0 °C at gastrulation and compared to 4.9 °C at fin flutter (Table 1). Hatchlings at 3.3 °C also had higher 18:1(n-9c) compared to 8.0 °C hatchlings. Temperature changes in the range of 6 °C–9 °C can alter membrane fluidity of some fish cells. For example, leucocytes in the head kidney of rainbow trout acclimated
to 6.5 °C had decreased SFA and increased PUFA in conjunction with increased membrane fluidity compared to 14.5 °C acclimated fish (Bowden et al., 1996). Thus, a 6 °C change may induce a change in membrane fluidity of certain lake whitefish embryonic cells via alterations of the fatty acid profile.