Tough for Fish?
1
Migration Identify the obstacles and check your answers on the right! What Makes Tough for Fish? 1. Grazing cattle can damage river banks and degrade water quality. 2. Runoff from fertilizers can degrade water quality. 3. Irrigation can reduce water levels; remaining water can then become too warm for native fishes. 4. Historic mill dams can affect the natural flow of rivers and prevent fish from migrating. 5. Traditional round culverts tend to hinder or totally block fish movement. 6. Non-native fish prey on juvenile migratory fish and disrupt the food chain. 7. Dams may delay or totally prevent migration and altered flow may favor non-migratory and/or non-native fish. 8. Predators intercept migrating fish in coastal waters. 9. Waste water discharge may degrade water quality. 10. See 5. 11. Fish trapped below culverts can be easy prey for birds. 12. See 5. 13. See 4. Abandoned dams are also unsafe. 14. Years ago, rivers were straightened so logs could get to mills. This degraded fish habitat. 15. Migratory fish may be legally harvested in other countries; here they are sold in a fish market. 16. Many species of birds eat migratory fish. 17. Some migratory fish are intercepted at sea en route to and from spawning habitat. 18. Migratory fish are an important food source for birds like bald eagles. 19. Air pollution from factories and sewage treatment plants can degrade water quality. 20. Migratory fish may be an unintended bycatch in fisheries targeting other species. 21. Migratory fish are an important natural food source for birds like ospreys. 22. Warming of rivers and oceans can impact fish survival. 23. A west coast elephant seal may prey on migratory fish. 24. An east coast harbor seal may prey on migratory fish. 25. The brown pelican is a natural predator of migratory fish. 26. Intake pipes can suck juvenile fish into the industrial plant’s cooling process. 27. Abandoned dams used during the log drive days continue to block fish migration. 28. See 5. Undersized culverts also disrupt natural flow and sediment transfer. 29. A changing climate can alter oceanic currents vital to migratory fish.
Transcript of Tough for Fish?
Migration Identify the obstacles and check your answers on the right!
What Makes
Tough for Fish?
1.
Graz
ing
cattl
e ca
n da
mag
e riv
er b
anks
and
deg
rade
wat
er q
ualit
y.2.
Ru
noff
from
ferti
lizer
s ca
n de
grad
e w
ater
qua
lity.
3.
Irrig
atio
n ca
n re
duce
wat
er le
vels
; rem
aini
ng w
ater
can
then
bec
ome
too
war
m fo
r nat
ive
fishe
s.
4.
Hist
oric
mill
dam
s ca
n af
fect
the
natu
ral fl
ow o
f riv
ers
and
prev
ent fi
sh fr
om m
igra
ting.
5.
Trad
ition
al ro
und
culv
erts
tend
to h
inde
r or t
otal
ly b
lock
fish
mov
emen
t. 6.
N
on-n
ativ
e fis
h pr
ey o
n ju
veni
le m
igra
tory
fish
and
dis
rupt
the
food
cha
in.
7.
Dam
s m
ay d
elay
or t
otal
ly p
reve
nt m
igra
tion
and
alte
red
flow
may
favo
r non
-mig
rato
ry a
nd/o
r non
-nat
ive
fish.
8.
Pr
edat
ors
inte
rcep
t mig
ratin
g fis
h in
coa
stal
wat
ers.
9.
W
aste
wat
er d
isch
arge
may
deg
rade
wat
er q
ualit
y.10
. Se
e 5.
11.
Fish
trap
ped
belo
w c
ulve
rts c
an b
e ea
sy p
rey
for b
irds.
12.
See
5.13
. Se
e 4.
Aba
ndon
ed d
ams
are
also
uns
afe.
14
. Ye
ars
ago,
rive
rs w
ere
stra
ight
ened
so
logs
cou
ld g
et to
mill
s. T
his
degr
aded
fish
hab
itat.
15.
Mig
rato
ry fi
sh m
ay b
e le
gally
har
vest
ed in
oth
er c
ount
ries;
her
e th
ey a
re s
old
in a
fish
mar
ket.
16.
Man
y sp
ecie
s of
bird
s ea
t mig
rato
ry fi
sh.
17.
Som
e m
igra
tory
fish
are
inte
rcep
ted
at s
ea e
n ro
ute
to a
nd fr
om s
paw
ning
hab
itat.
18.
Mig
rato
ry fi
sh a
re a
n im
porta
nt fo
od s
ourc
e fo
r bird
s lik
e ba
ld e
agle
s.19
. Ai
r pol
lutio
n fro
m fa
ctor
ies
and
sew
age
treat
men
t pla
nts
can
degr
ade
wat
er q
ualit
y.20
. M
igra
tory
fish
may
be
an u
nint
ende
d by
catc
h in
fish
erie
s ta
rget
ing
othe
r spe
cies
.
21.
Mig
rato
ry fi
sh a
re a
n im
porta
nt n
atur
al fo
od s
ourc
e fo
r bird
s lik
e os
prey
s.22
. W
arm
ing
of ri
vers
and
oce
ans
can
impa
ct fi
sh s
urvi
val.
23.
A w
est c
oast
ele
phan
t sea
l may
pre
y on
mig
rato
ry fi
sh.
24.
An e
ast c
oast
har
bor s
eal m
ay p
rey
on m
igra
tory
fish
.25
. Th
e br
own
pelic
an is
a n
atur
al p
reda
tor o
f mig
rato
ry fi
sh.
26.
Inta
ke p
ipes
can
suc
k ju
veni
le fi
sh in
to th
e in
dust
rial p
lant
’s co
olin
g pr
oces
s.27
. Ab
ando
ned
dam
s us
ed d
urin
g th
e lo
g dr
ive
days
con
tinue
to b
lock
fish
mig
ratio
n.
28.
See
5. U
nder
size
d cu
lver
ts a
lso
disr
upt n
atur
al fl
ow a
nd s
edim
ent t
rans
fer.
29
. A
chan
ging
clim
ate
can
alte
r oce
anic
cur
rent
s vi
tal t
o m
igra
tory
fish
.
