Effects of temperature and
salinity on the reproductive success of Arctic charr, Salvelinus alpinus
(L.): egg composition, milt characteristics and fry survival
C.B.
Atse, C. Audet, J. de la Noüe-2002
Aquaculture
Research, 33(4):
299-309
Abstract:
The effects of temperature and salinity on the
reproductive success of Arctic charr, Salvelinus alpinus (L.), were
examined by holding broodstock under the following conditions from mid-May
until the end of September: fresh water at ambient temperature (NFW; 8-16
°C);
salt water (25-30 ppt) at ambient temperature (NSW; 4-10 °C);
fresh water cooled to saltwater temperature (CFW; 4-10 °C);
or salt water heated to freshwater temperature (HSW; 8-16 °C).
The relative fecundity of females was similar among groups (P >
0.05;
2685 +/- 706
eggs), but females reared in NSW produced significantly larger eggs than
those raised in NFW. The highest spermatozoa concentrations were found in
milt from males reared in SW and the highest milt glucose concentration was
from males kept under coldwater conditions (CFW, NSW). Eggs from NSW and HSW
females contained more proteins than eggs produced by NFW females. Eggs from
NSW females also contained 40% more lipids than was observed in the other
groups, and total energy content was 27% higher in eggs from NSW females
than in eggs from NFW females. When FW was cooled (CFW), females produced
eggs with protein contents similar to those in NSW, but the lipid contents
remained 30% lower. Finally, the best survival at the eyed stage and at
hatch was observed in families produced by NSW broodstock. Intermediate
values were observed in families from NFW or CFW while the highest mortality
occurred in families from the HSW group. All these results suggest that,
under the experimental conditions used in the present study, coastal
seawater conditions offered the most favourable summer rearing conditions
with respect to the reproductive success of Arctic charr.
(ISMER,
UQAR, 310 allée des Ursulines, Rimouski (Qué.), Canada G5L 3A1. e-mail of
C. Audet: celine_audet@uqar.qc.ca)