Poor
survival
results
for
P.
helleri
nectochaetes
and
slower
growth
rates
of
P.
nuntia
in
fi
ltration
beds
(see
results)
prompted
a
focus
from
2007
on
the
stocking
of
one-month-old
P.
helleri
.
Tub- and
tank-based
experiments
were
designed
to
assess
the
survival
and
growth
of
nursery-reared
P.
helleri
juveniles
at
stocking
densities
ranging
from
1000
to
6000
m
−
2
.
In
both
trials,
fi
ltration
beds
were
operated
for
about
four
months
using
the
standardised
water
treatment
rate
(1500
L
m
−
2
d
−
1
),
where
water
fl
ows
began
on
the
day
before
stocking.
Juveniles
for
stocking
into
different
replicates
of
each
density
in
these
trials
were
sourced
from
different
nursery