Seasonality
is
a
consistent
component
of
aquatic
ecosystems
yet
most
fish
biological
and
ecotoxicological
studies
commonly
employ
field
sampling
protocols
focused
during
the
warm
open
water
season
with
minimal
emphasis
placed
on
winter
sampling,
especially
for
north-temperate
latitude
ecosystems.
Such
strategies
limit
our
understanding
poikilotherm
biology
ecology
overwintering
seasons.
Here,
I
investigated
seasonal
changes
in
yellow
perch
(Perca
flavescens)
biology,
ecotoxicology
over
one-year
period
Lake
Manganese.
Significant
seasonality
was
observed
metrics
including
energy
densities
(kJ/g),
gonadosomatic
indices,
whole-body
lipid
contents,
carbon
stable
isotope
values
(δ13C).
Mercury
concentrations
quantified
within
single
age
class
displayed
significant
individual
variability,
Hg
fall
collected
fishes
being
higher
than
those
spring
summer
fishes.
Both
protein
mass
δ13C
were
predictors
bioaccumulation
by
Manganese
perch.
This
study
among
few
to
demonstrate
role
pollutant
bioaccumulation.
Furthermore,
these
results
need
include
establish
entire
growing
datasets
under
current
climate
change
predictions.
The Science of The Total Environment,
Journal Year:
2024,
Volume and Issue:
931, P. 172703 - 172703
Published: May 3, 2024
Methylmercury
(MeHg)
readily
bioaccumulates
and
biomagnifies
in
aquatic
food
webs
leading
to
elevated
concentrations
fish
may
thus
induce
toxicity.
Oxidative
stress
is
a
suggested
effect
of
MeHg
bioaccumulation
fish.
However,
studies
on
how
triggers
oxidative
wild
are
scarce.
The
purpose
this
study
was
link
the
subcellular
distribution
liver
northern
pike
from
St.
Maurice
River
(Québec,
Canada),
affected
by
two
run-of-river
(RoR)
dams,
artificial
wetlands,
forest
fires,
logging
activity,
lipid
peroxidation
as
an
indicator
stress.
We
also
evaluated
protective
effects
glutathione
(GSH)
system
selenium
(Se),
they
known
alleviate
A
customized
partitioning
protocol
used
separate
into
metal-sensitive
(mitochondria,
microsome/lysosome
HDP
-
heat-denatured
proteins)
metal-detoxified
fractions
(metal-rich
granules
HSP
heat-stable
proteins).
examined
relation
among
THg,
MeHg,
Se
concentration
livers
fractions,
hepatic
ratio
total
GSH
(GSH
Environmental Science & Technology,
Journal Year:
2021,
Volume and Issue:
55(5), P. 2949 - 2959
Published: Feb. 3, 2021
Unlike
large
dams
which
favor
methylation
of
Hg
in
flooded
soils
over
long
periods,
run-of-river
are
designed
to
flood
a
limited
area
and
therefore
not
expected
significantly
affect
mercury
(Hg)
cycling
or
carbon
processing.
We
studied
the
cycles
within
food
webs
from
several
sectors
along
Saint-Maurice
River,
Quebec,
Canada,
that
differ
how
they
influenced
by
two
other
watershed
disturbances.
observed
peak
concentrations
fish
five-year
postimpoundment,
but
these
levels
were
reduced
three
years
after
this
peak.
Methylmercury
low
trophic
level
invertebrates
related
their
source
(δ13C)
rather
than
positions
(δ15N).
Biomagnification,
measured
magnification
slopes,
was
driven
mainly
methylmercury
low-trophic
organisms
environmental
factors
organic
matter
degradation
Hg-methylation.
River
sectors,
δ13C
δ15N,
predicted
up
80%
variability
web
concentrations.
The
installation
pondages,
association
with
disturbances,
altered
processing,
promoted
Hg-methylation
its
accumulation
at
base
web,
led
temporary
increase
fish.
Toxics,
Journal Year:
2023,
Volume and Issue:
11(2), P. 181 - 181
Published: Feb. 16, 2023
Mercury
(Hg)
is
a
dangerous
and
persistent
trace
element.
Its
organic
highly
toxic
form,
methylmercury
(MeHg),
easily
crosses
biological
membranes
accumulates
in
biota.
Nevertheless,
understanding
the
mechanisms
of
dietary
MeHg
toxicity
fish
remains
challenge.
A
time-course
experiment
was
conducted
with
juvenile
white
seabreams,
Diplodus
sargus
(Linnaeus,
1758),
exposed
to
realistic
levels
feed
(8.7
μg
g-1,
dry
weight),
comprising
exposure
(E;
7
14
days)
post-exposure
(PE;
28
periods.
Total
Hg
increased
time
gills
liver
during
E
decreased
significantly
PE
(though
control
were
reached
only
for
gills),
exhibiting
higher
(2.7
times)
than
gills.
Nuclear
magnetic
resonance
(NMR)-based
metabolomics
revealed
multiple
often
differential
metabolic
changes
between
organs.
Gills
exhibited
protein
catabolism,
disturbances
cholinergic
neurotransmission,
osmoregulation
lipid
energy
metabolism.
However,
provoked
altered
metabolism
amino
acids,
likely
activation
defensive
strategies.
allowed
partial
recovery
both
organs,
even
if
occurrence
oxidative
stress
Overall,
these
findings
support
organ-specific
responses
according
their
sensitivity
exposure,
pointing
out
that
indications
obtained
biomonitoring
studies
may
depend
also
on
selected
organ.
Environmental Toxicology and Chemistry,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 23, 2025
Abstract
Monitoring
selenium
(Se)
concentrations
in
fish
ovaries
is
an
important
tool
for
evaluating
the
ecological
risk
posed
by
Se
aquatic
systems.
Most
guidance
recommends
sampling
as
closely
possible
to
when
spawn
on
premise
that
mobilized
from
liver
ovary
during
vitellogenesis,
and
therefore,
early
phases
of
oocyte
maturation
may
underestimate
egg
at
time
spawning.
In
this
study,
we
evaluated
data
two
species
with
synchronous
development
(Ptychocheilus
oregonensis
Prosopium
williamsoni),
one
asynchronous
(Richardsonius
balteatus),
where
mode
unclear
(Mylocheilus
caurinus).
A
multivariate
analysis
a
function
location,
size,
gonado-somatic
index
(GSI)
demonstrated
was
strongly
negatively
correlated
GSI
but
only
weakly
development.
R.
balteatus,
relationship
between
expressible
(released)
remaining
observed,
∼54%
average.
Overall,
our
findings
suggest
current
understanding
mechanisms
which
maternally
transferred
oocytes
not
entirely
correct
raises
questions
regarding
how
reproductive
cycle
ovaries.
Further,
have
significant
implications
interpretation
monitoring
collected
unripe
fish.
We
developed
regression-based
models
are
biased
females
spawning
condition
demonstrate
bias
can
impact
evaluation
