Behavioral changes in fishes and crabs in contaminated estuaries Predator/prey alterations could have consequences for birds Judith S. Weis Rutgers University.
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Behavioral changes in fishes and crabs in contaminated estuaries
Predator/prey alterations could have consequences for birds
Judith S. WeisRutgers University
Collection Sites
Piles Creek (PC)Polluted Site - Linden, NJ
Great Bay-Mullica River Estuary (TK)Cleaner Reference Site- Tuckerton, NJ
Sites
Piles Creek (PC)Polluted Site - Linden, NJSurrounded by industrial sites, a sewage treatment plant, and a major highway. Elevated levels of organic contaminants and metals have been found in sediments and biota.
Collection Sites
Great Bay-Mullica River Estuary (TK)Cleaner Reference Site- Tuckerton, NJ part of the Jacques Cousteau National Estuarine Research Reserve, part of 3,500 acres of protected salt marsh.
BACKGROUND• MUMMICHOGS (KILLIFISH, FUNDULUS HETEROCLITUS)
FROM CONTAMINATED PILES CREEK ARE RESISTANT TO METHYLMERCURY, BUT RESISTANCE IS RESTRICTED TO GAMETES AND EMBRYONIC STAGES
• AS ADULTS, THEY DO NOT GROW AS WELL OR LIVE AS LONG AS FISH FROM CLEANER ENVIRONMENT
• ALTERED FEEDING BEHAVIOR MAY PLAY A ROLE – COMPARE FEEDING WITH THAT OF TUCKERTON (CLEAN) FISH
FEEDING EFFICIENCY OF PC AND TK FISH PC TK
STRIKES/PURSUIT 1.93 + 0.62 1.85 + 0.10
STRIKES/KILL 10.38 + 10.06 6.71 + 8.66
STRIKES/FISH/MIN 0.55 + 0.52 0.97 + 0.51* * P < 0.05
X + SD X + SD
NUMBER OF F. HETEROCLITUS EATEN BY BLUE CRABS OVER 14 DAYS
ORIGIN OF FISH # EATEN #NOT EATEN TOTAL
PC 23 7 30
TK 12 19 30
PREDATOR AVOIDANCE
• COMPARE SURVIVAL OF PC AND TK FISH WITH BLUE CRAB (CALLINECTES SAPIDUS) PREDATORS
NUMBER OF F. HETEROCLITUS EATEN BY BLUE CRABS OVER 14 DAYS
ORIGIN OF FISH # EATEN #NOT EATEN TOTAL
PC 23 7 30
TK 12 19 30
More contaminated fish are more likely to be eaten by predator, and pass contaminants up the food chain.
Blue Crabs- Callinectes sapidus
• Prey capture ability of adults from TK and contaminated Hackensack Meadowlands
• Compare predator avoidance ability of juveniles from TK and HM w. adult blue crab predators
Jessica Reichmuth
Capture of Juvenile Blue Crab Prey
Ca
ptu
re ti
me
(h
rs)
0
10
20
30
40
50
60
70
Population
HMTK
Adult Capture of Juvenile Blue Crab Prey Time to capture 2 of 4 juveniles
Capture of Mummichog Prey
0
1
2
3
4
5
6
7
8
Population
HMTK
# m
um
mic
hog
s e
ate
n
Capture of Mussel PreyT
ota
l We
t We
igh
t (g
) E
ate
n
0
5
10
15
20
25
30
35
40
45
Population
HMTK
Capture of Mussel Prey
Capture of Fiddler Crab PreyT
otal
# o
f fid
dler
cra
bs e
aten
02468
101214161820
Population
HMTK
8.7
27.35.1
0.4
3.4
0
1.5
11.4
5.7
9.8
10
32.9
22.4
0.3
32.4
7.5
10.9 10.3
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
1 2
Unknown
Sediment/Detritus
Plant/Algae
Fish
Unknown Crustacea
Bivalve
Polychaete
Amphipod
Crab
HM Stomachs TK Stomachs
Field: Stomach Contents
HM Transplants to TK or fed clean TK food in the lab: Capture of
juvenile blue crabs
0
10
20
30
40
50
60
70
Treatment
HM (base)
HM:TK
HM + TK food
Tim
e to
co
nsu
me
50
% p
rey
(hrs
)
A
B B
TK Transplants to HM or fed HM food (killifish) in lab: capture of
juvenile blue crabs
Tim
e to
co
nsu
me
50
% p
rey
(hrs
)
0
50
100
150
200
250
Treatment
TK (base)
TK:HM
TK + HM foodA
B
C
Reichmuth et al. ’09 Estuar Coast.
Predator Avoidance Results
To
tal #
su
rviv
ors
0
5
10
15
20
25
30
35
40
Population
HMTK
Predator (adult Blue Crab) Avoidance by Juveniles
Bluefish (Pomatomus saltatrix) studies:
A temporary resident
Allison Candelmo
Spawn in the ocean and then move into estuaries in the Spawn in the ocean and then move into estuaries in the spring. spring. Spend critical periods of growth and development during Spend critical periods of growth and development during first summer before going to the ocean for the winterfirst summer before going to the ocean for the winter
What happens when they spend this first summer in contaminated estuaries?
Trophic Transfer Experiments
• Collect 60 YOY bluefish from Tuckerton in early summer as they enter the estuary• Feed frozen and live Brevoortia and Fundulus from either
Hackensack or Tuckerton (control) for 4 months in the laboratory
• Quantify feeding and swimming activity• Sacrifice fish and length and weight recorded• Analyze Laboratory bluefish for PCBs and Hg
Feeding experiments after eating TK or HM food for 4 months
TKfed - up to 5x fasterConsumption rate TKfed - up to 2x more food consumed
Time Required to Consume Ration
0
2
4
6
8
10
12
14
16
1 2 3
Trial
Sec
onds
TuckertonHackensack
Amount of mummichogs consumed
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 1 2 3 Tuckerton Hackensack#
cons
umed
per
blu
efis
h
a
b
Swim Rate
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 1 2 3Tuckerton Hackensack
Rat
e (m
/s)
Swimming activity
Poorer schooling – more milling about – would make them more susceptible to predation
Candelmo et al. 2010 Est. Coasts
Size Distribution
PCB levels in mummichogs (Fh) and menhaden (Bt) from bluefish stomachs vs collected in nets
Field Bluefish in Hackensack
• Smaller than at Tuckerton in the fall when it is time to migrate back to the ocean
• Most with empty stomachs • Contaminants like PCBs and mercury are
biomagnified in bluefish over levels in their prey. • Fish with higher levels of contaminants are more
impaired, more likely to be captured and transfer more contaminants to predators such as birds.
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