Effects of temperature and parental background on the embryonic survival and metabolic rate of newly hatched Arctic charr
European Network for the Dissemination of Aquaculture
RTD Information (Q5CA-2000-30105) and previously FAIR-3837, Aquaflow ref. :
TL2003-158
Arctic charr (Salvelinus
alpinus L.) is an
endangered species in Lake Saimaa, south-eastern Finland. As a part of a
stock enhancement programme, several year classes of cultivated brood stocks
have been founded. The genetic diversity of Lake Saimaa Arctic charr has
recently been studied and it has proven to be low, probably due to
population decrease and subsequent inbreeding.
The aim of this study was to find out whether
embryonic survival and metabolic rate of newly hatched Arctic charr are
affected by parental background or temperature. To study possible
interactions between the genotypes and environmental during early
ontogenetic development, family groups were created by crossing randomly
selected single parents from cultivated brood fish. The eggs of these Arctic
charr families were incubated at 2˚C and 7˚C, and embryonic
survival was determined at the eyed stage. After hatching, oxygen
consumption of the fry was measured at the incubation temperatures.
Temperature was found to have effects on both
embryonic survival and standard metabolic rate of Arctic charr while
parental background affected only survival. In all except one family,
embryonic survival was higher at low incubation temperature. Mean survival
of all families was 60,6% at 2˚C while at 7˚C it was 46,0%.
Variability in the embryonic survival could be attributed to the female
parental background at both temperatures whereas the male parental
background only had an effect at the lower temperature. Standard metabolic
rate of fry was higher at 7˚C than 2˚C. Parental background was
not found to affect the standard metabolic rate of Arctic charr.
Low incubation temperature is advantageous for Arctic
charr. The lower mortality, combined with the longer utilisation of yolk
reserves, shows well the adaptation of Arctic charr to cold waters.
For more information, contact:
Hannu Huuskonen
University of Joensuu
Karelien Institute, Department of Ecology
FIN – P.O Box 111,
80101 JOENSUU - Finland
Tel.: +358 132513480
Fax: +358 132513449
E-mail: hannu.huuskonen@joensuu.fi