Aquatic Conservation Marine and Freshwater Ecosystems,
Год журнала:
2023,
Номер
33(11), С. 1295 - 1308
Опубликована: Сен. 6, 2023
Abstract
Understanding
the
habitat
requirements
of
fishes
throughout
their
life
cycle
is
essential
for
effective
conservation.
Despite
growing
need
to
conserve
anguillid
eels,
current
understanding
ontogenetic
shifts
during
riverine
stages
remains
limited,
particularly
Japanese
eel
Anguilla
japonica
and
Indo‐Pacific
marmorata
.
Here,
changes
in
use
these
two
species
were
investigated
southern
Japan
rivers,
where
they
coexist.
Eels
classified
into
total
length
(TL)
classes
at
10
cm
intervals,
generalized
additive
models
constructed
using
as
an
ordinal,
quasi‐continuous
explanatory
variable.
The
showed
that
changed
with
growth;
both
shifted
deeper
more
lentic
habitats
grew
larger.
Small‐
mid‐sized
(<25
25–55
TL,
respectively)
A.
used
smaller
substrates,
ranging
from
sand/silt
cobbles,
than
small‐
,
which
mainly
lotic
cobble
boulder
substrates.
However,
compared
small‐sized
conspecifics,
larger
such
pebbles
suggesting
interspecific
overlap
relatively
high
individuals
species.
Large
(
85
cm)
substrates
results
suggest
a
fine
body
size
classification
including
variable
capture
gradual
use,
improving
evaluation
eels.
Preserving
environmental
heterogeneity
river
terms
water
depth,
velocity
substrate
would
facilitate
segregation
conspecifics
allospecifics
same
thereby
promoting
conservation
Frontiers in Marine Science,
Год журнала:
2025,
Номер
12
Опубликована: Март 20, 2025
The
decline
in
eel
resources,
coupled
with
the
challenges
of
morphological
identification
and
rise
illegal
trade,
highlights
urgent
need
for
accurate
species
techniques.
To
address
this,
a
multiplex
PCR
assay
was
developed,
targeting
mitochondrial
Cytochrome
b
gene.
Species-specific
primers
were
designed
their
efficacy
validated
through
single
PCR.
conditions
then
optimized
to
enable
simultaneous
amplification
five
major
species.
This
exhibited
high
accuracy,
specificity,
sensitivity,
successfully
identifying
all
even
when
DNA
concentrations
low.
offers
rapid
cost-effective
solution
identification,
potential
significantly
bolster
conservation
efforts.
By
enabling
it
can
help
combat
trade
support
sustainable
management
resources.
Journal of Fish Biology,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 11, 2025
Abstract
River
connectivity
is
crucial
for
the
European
eel
(
Anguilla
anguilla
)
to
complete
its
complex
life
cycle,
which
vital
upstream
recruitment
declining
population
of
this
critically
endangered
catadromous
fish.
Eel
passes,
or
ladders,
are
frequently
installed
on
riverine
structures,
such
as
dams
and
weirs,
mitigate
barrier
effects
restore
migrating
eel.
Efforts
optimise
effectiveness
passes
have
previously
focused
ascent
section,
quantifying
climbing
substrate,
longitudinal
slope,
lateral
slope
flow
rate.
However,
conditions
at
pass
crest
also
impact
rapidity
success
movements.
Using
controlled
experiments
custom‐built
with
contrasting
shapes
(curved
vs.
sloped)
directions
(ascending
descending),
we
quantified
effect
attempt
success,
passage
efficiency
speed
ascending
juvenile
Only
three
four
treatments
(sloped
ascending,
curved
descending
ascending)
demonstrated
efficiencies
significantly
greater
than
50%.
Transit
was
quicker
(~3.5
min)
in
a
shape
compared
control.
Our
findings
indicate
that
simple
modifications
configuration
delivery
can
help
minimise
delay
enhance
efficiency.
This,
turn,
will
increase
migration
contribute
conservation
management
goals,
EU
Regulation
The
Eels
(England
Wales)
Regulations
2009.
Canadian Journal of Fisheries and Aquatic Sciences,
Год журнала:
2022,
Номер
80(1), С. 14 - 26
Опубликована: Окт. 28, 2022
Many
anguillid
eel
species
display
facultative
catadromy.
Some
spend
their
entire
life
cycle
in
marine
coastal
areas,
but
the
geographical
extent
of
this,
especially
at
extremes
distributional
ranges,
is
unknown.
We
analysed
otolith
Sr:Ca
and
Ba:Ca
from
yellow-stage
European
(
Anguilla
anguilla)
sampled
along
coast
Norway
several
freshwater
lakes
(58°N–63°N),
to
infer
initial
settlement
later
movement
patterns
with
regards
habitat
salinity.
Most
(80%)
habitats
n
=
371)
had
settled
remained
water,
20%
moved
between
were
hence
classified
as
inter-habitat
shifters.
Among
99),
80%
fresh
The
average
growth
rates
for
water
residents,
shifters,
residents
35,
27,
17
mm·year
–1
,
respectively.
Northern
shallow
may
serve
important
yellow
be
critical
buffer
population
against
general
decrease
continental
recruitment.
Aquatic Conservation Marine and Freshwater Ecosystems,
Год журнала:
2023,
Номер
33(11), С. 1295 - 1308
Опубликована: Сен. 6, 2023
Abstract
Understanding
the
habitat
requirements
of
fishes
throughout
their
life
cycle
is
essential
for
effective
conservation.
Despite
growing
need
to
conserve
anguillid
eels,
current
understanding
ontogenetic
shifts
during
riverine
stages
remains
limited,
particularly
Japanese
eel
Anguilla
japonica
and
Indo‐Pacific
marmorata
.
Here,
changes
in
use
these
two
species
were
investigated
southern
Japan
rivers,
where
they
coexist.
Eels
classified
into
total
length
(TL)
classes
at
10
cm
intervals,
generalized
additive
models
constructed
using
as
an
ordinal,
quasi‐continuous
explanatory
variable.
The
showed
that
changed
with
growth;
both
shifted
deeper
more
lentic
habitats
grew
larger.
Small‐
mid‐sized
(<25
25–55
TL,
respectively)
A.
used
smaller
substrates,
ranging
from
sand/silt
cobbles,
than
small‐
,
which
mainly
lotic
cobble
boulder
substrates.
However,
compared
small‐sized
conspecifics,
larger
such
pebbles
suggesting
interspecific
overlap
relatively
high
individuals
species.
Large
(
85
cm)
substrates
results
suggest
a
fine
body
size
classification
including
variable
capture
gradual
use,
improving
evaluation
eels.
Preserving
environmental
heterogeneity
river
terms
water
depth,
velocity
substrate
would
facilitate
segregation
conspecifics
allospecifics
same
thereby
promoting
conservation
