摘要:This study informs the restoration and development of salmonid
fisheries and aquaculture facilities regarding water quality and
light effects on hatching survival in spring channels. Brook trout
Salvelinus fontinalis eggs were hatched in springs from karst and
silica-clastic aquifers to determine whether survival was affected
by water quality in differing geological areas. Nitrogen gas saturation
(N2) was highest in karst springs and impacted survival, with
a negative relationship between N2 and survival during hatching
(> 110% N2 corresponded to 70.5% survival). A multiple regression
model was developed to predict survival that included
N2, acid neutralizing capacity (ANC), and light intensity (Light)
following the equation: %Survival ¼ 3:00 Nð Þ2 þ 0:08 ANC ð Þ
0:01 Light ð Þþ 404:5: In a follow-up experiment, brook trout eggs
were fertilized and hatched in hatching boxes in high and low levels
of ultraviolet light (UV), fluorescent light, and complete darkness
to test the effects of UV and light intensity on survival.
Logistic regression was used to model the probability of mortality
as a function of UV-B intensity. Results indicated freshly fertilized
eggs were more severely impacted by light and UV than posteyed
eggs, and both UV and fluorescent light treatments experienced
high mortality compared to the treatment in complete
darkness. Karst springs with intermediate concentrations of calcium
and increased ANC provide improved water quality for salmonids
as compared to silica-clastic aquifers; however, high N2
can have negative effects on survival which, could be overcome
by aeration within spring channels. Furthermore, using advanced
aquaculture techniques, it may be possible to develop a brood
stock that is resistant to the effects of N2. Effects of UV and light
intensity pose additional challenges at early life stages for salmonids
which, can be overcome by shading hatch boxes in the
spring channel.