Nutrigenomics imerging face of aquaculture nutrition
Â
SURF presentation
1. Effects of Resmethrin and PBO
on Foraging Habits of Juvenile
Callinectes sapidus
Erin Plachy
Kaitlyn Schroeder-Spain
& Dr. D. L. Smee
2. Blue Crabs (Callinectes
sapidus)
• Key predator and prey
species in estuarine systems
• Commercially important:
Texas landings at lowest
levels since 1960s
– Decline due to loss of habitat,
overfishing, and pollution
• Blue crab importance makes
it necessary to mitigate
additional pressures on
existing populations
(Williams, 1973; Sutton & Wagner, 2007; Guillory et al., 2001)
3. Introduction
• Growing concern for insecticide
runoff into estuaries
– After significant rainfall,
pesticides have been found in
nearby estuaries
– Mid-Texas Coast study found
93.4% of all samples contained
triazine herbicides
• Insects and crabs are related
– Share target enzymes
• Juvenile blue crabs grow up in
estuaries
– After mating, males go to lower
salinities and females move to
higher salinities to release eggs
(Pennington et al. 2001)
4. Similar Studies
• Virtually no studies done on crabs
with Res. + PBO, but there are several
that have been conducted with
mercury and other heavy metals
– Produce similar effects on aquatic
organisms
• Contaminants like mercury have been
found to cause reduced feeding and
foraging ability of aquatic species
such as killifish
– Can affect organism’s motivation to
feed
– Reduces foraging search effectiveness
– Reduce ability to capture prey
(Weis et al. 2001)
5. Mercury Studies
• When exposed to mercury,
blue crabs have a decreased
ability to capture more
active prey, but consumed
equal amounts of less active
prey
– Blue crabs may be more
affected by reduced
coordination rather than lack
of motivation or hunger
(Reichmuth et al. 2009; Weis et al. 1999, 2000, 2001, 2011)
6. SCOURGE™
• Study sublethal
effects of Res. + PBO
on foraging ability of
juvenile blue crabs
• Some studies have
investigated effects of
pesticides on blue
crabs, but sublethal
effects of ingredients
in SCOURGE™ on
crabs are unknown
(Osterburg et al. 2012; Horst and Walker 1999)
7. • SCOURGE™: used primarily in mosquito pesticide
spraying
• Resmethrin: pyrethroid insecticide
– Interferes with nervous system
• Piperonyl Butoxide (PBO): synergist
– Inhibits metabolization of toxins
– Makes resmethrin more potent
(Zulkosky et al., 2005; WHO, 2001)
8. Mesocosm: Experimental
Design
• Juvenile male blue crabs and brown
shrimp caught in Corpus Christi, TX
– Crabs: 35-60 mm; Shrimp 35-50 mm
– Crabs must have chelipeds,
swimming legs, and most walking
legs
– Salinity: 18-20 (PSU)
– Acclimated to lab for min. 48-hrs
• Exposed to treatment or control for 3
or 12 hours, separately
• Each mesocosm:
– A filter, oyster shell layer, and
untreated saltwater
– 1 crab + 8 shrimp
9. Measured crab and
shrimp length
12-hr Exposure
CONTROL
Crab: control-ethanol
Shrimp: control-ethanol
(n=12)
LOW TREATMENT
Crab: 1:3 Res. + PBO
Shrimp: control-ethanol
(n=6)
HIGH TREATMENT
Crabs: 10:30 Res. + PBO
Shrimp: control-ethanol
(n=6)
3-hr Exposure
HIGH TREATMENT
Crab: 10:30 Res. + PBO
Shrimp: control-ethanol
(n=2)
High mortality in 12-hr 10:30
exposure, so new crabs were
measured and put in high
exposure for 3 hrs
*Indicates control ethanol
10. Data Collection
• 1 crab & 8 shrimp
• Observations recorded:
– # shrimp alive
– shrimp dead at each hr
– total shrimp dead
– # shrimp out
– if/where crab was hiding
(filter or shell)
– oyster piling occurrence
• Data recorded at hour:
– 0, 1, 2, 3, 6, 8, 12, 24, 36,
48, 60, & 72 hrs
– or until no shrimp left
11. Data Analysis
• Statistical tests
completed in either JMP
or Excel
– Repeated measures
ANOVA
– Post hoc: Students t-test,
with Bonferroni correction
to compare treatments
12. Average Shrimp Alive: Res. + PBO
With High Exposure 12-hr
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 6 8 12 24
NumberofShrimpAlive
Hour
Control Ethanol 10:30 ppb 12-hr
10:30 ppb Res. +PBO ate significantly less than control (p=0.006)
p = 0.006
13. Average Shrimp Alive: Res. + PBO
With High Exposure 12-hr
0
1
2
3
4
5
6
7
8
9
10
0 1 2 3 6 8 12 24
NumberofShrimpAlive
Hour
Control Ethanol 10:30 ppb 3-hr
1:3 ppb 12-hr 10:30 ppb 12-hr
10:30 ppb Res. +PBO ate significantly less than control (p=0.006)
14. Results
• 10:30 ppb Res. + PBO
(12-hr) not analyzed
because of low
replication (n=2)
• Focus on the
treatments that had
more replicates
15. Repeated Measures ANOVA
• Treatment has a nearly
significant ( p = 0.0630) effect
on consumption
– Due to low number of replicates,
could be considered significant
in order to avoid making a Type
II error
• Time is a significant factor
(p<0.0001)
• Time-treatment interaction was
not significant (p=0.280)
16. Average Shrimp Alive: Res. + PBO
0
1
2
3
4
5
6
7
8
9
0 1 2 3 6 8 12 24
NumberofShrimpAlive
Hour
Control Ethanol 10:30 ppb 3-hr 1:3 ppb 12-hr
Treatment has a nearly significant ( p = 0.0630) effect on consumption
p=0.0796 p=0.0079
p=0.0004
17. Post hoc Analysis: Students t-test
• 1:3 ppb Res. + PBO (12-hr)
– crabs ate more than the
control ethanol group
(p=0.0079)
• 10:30 ppb Res. + PBO (3-hr)
– Nearly significant: crabs ate
less than the control
ethanol group (p=0.0796)
• 10:30 ppb Res. + PBO ate
less than 1:3 ppb Res. + PBO
treatment (p=0.0004)
20. Discussion
• In 10:30 ppb Res. + PBO 12-hr
treatment, surviving crabs
waved chelipeds erratically and
flipped upside-down
– Dead crabs were found upside-
down having ejected their claws
– Evidence of neuromuscular
dysfunction
• 10:30 ppb 3-hr treatment did
not act as severely as the 10:30
12-hr
– It is expected they endured
similar, but reduced, side effects
21. Discussion
• With poor motor skills,
blue crabs were less able to
catch active prey
• Consistent with the 10:30 3-
hr ppb exposure
– Ate less and at a slower pace
• Similar results to mercury
studies
22. Unexpected Results
• 1:3 ppb Res. + PBO
surprisingly ate significantly
more than the control group
– Was expected to eat less
– Inconsistent with other studies
• Could have the opposite effect
of the higher exposure (10:30
ppb)
– Crabs could begin to consume
more, increasing predation
pressure
23. Implications
• Pesticides could potentially change community
structure
– In contaminated waters, grass shrimp are able to
effectively avoid predators and partition their
energy, favoring growth and reproduction
– Effect of contamination was offset by decrease in
predation pressure
– Result was more numerous, larger shrimp
• With blue crabs not being able to target active
prey, predation pressure on those prey species
is decreased
(Reichmuth et al. 2009)
24. Implications
• Exposed to pesticides, blue crabs
would not be able to forage well,
having to select less optimal prey
– Generalist diet would narrow
– May not get proper nutrition
• Predation pressure would be relieved
for many prey species who would then
be allowed to increase in numbers
– Community structure based on
predator-prey interactions would shift
(Weis et al. 1999, 2011)
25. Further Experimentation
• In the future I would repeat the
experiment with increasing
concentrations of Res. + PBO in
order to see the trend in amount
of shrimp alive per hour for each
exposure time
• At what concentration of Res. +
PBO do the crabs start feeling
the negative effects?
• How do exposures above or
below 1:3 ppb Res. + PBO affect
foraging ability?
26. Works Cited
• Williams, A. B. (1973). The Swimming Crabs of the Genus Callinectes (Decapoda: Portunidae). Fishery Bulletin 72: 685-692.
• Sutton, G., and T. Wagner. (2007). Stock Assessment of Blue Crab (Callinectes sapidus) in Texas Coastal Waters. Texas Parks and Wildlife
Department Management Data Series No. 249.
• Guillory, V., H. Perry, P. Steele, T. Wagner, W. Keithly, B. Pellegrin, J. Peterson, T. Floyd, B. Buckson, L. Hartman, E. Holder, and C. Moss,
(2001, October). The Blue Crab Fishery of the Gulf of Mexico, United States: A Regional Management Plan. Gulf States Marine Fisheries
Commission.
• Pennington, P. L., J. W. Daugomah, A. C. Colbert, M. H. Fulton, P. B. Key, B. C. Thompson, E. D. Strozier, and G. I. Scott. (2001). Analysis of
Pesticide Runoff From Mid-Texas Estuaries and Risk Assessment Implications for Marine Phytoplankton. Journal of Environmental Science
and Health B36: 1-14.
• Weis, J. S., G. Smith, T. Zhou, C. Santiago-Bass, and P Weis. (2001). Effects of Contaminants on Behavior: Biochemical Mechanisms and
Ecological Consequences. BioOne 51: 209-217.
• Reichmuth, J. M., R. Roudez, T. Glover, and J. S. Weis. (2009). Differences in Prey Capture Behavior in Populations of Blue Crab
(Callinectes sapidus Rathburn) from Contaminated and Clean Estuaries in New Jersey. Estuaries and Coast, 32: 298-308.
• Weis, J. S., G. M. Smith, and T. Zhou. (1999). Altered predator/prey behavior in polluted environments: implications for fish conservation.
Environmental Biology of Fishes 55: 43-51.
• Weis, J. S., G. Smith, and C. Santiago-Bass. (2000). Predator/prey interactions: a link between the individual level and both higher and
lower level effects of toxicants in aquatic ecosystems. Journal of Aquaric Ecosystem Stress and Recovery 7: 145-153.
• Weis, J. S., L. Bergey, J. Reichmuth, and A. Candelmo. (2011). Living in a Contaminated Estuary: Behavioral Changes and Ecological
Consequences for Five Species. BioOne 61: 375-385.
• Osterburg, J. S., K. M. Darnell, T. M. Blickley, J. A. Romano, D. Rittschof. 2012. Acute toxicity and sub-lethal effects of common pesticides
in post-larval and juvenile blue crabs, Callinectes sapidus. Journal of Experimental Marine Biology and Ecology. 424-425: 5-14.
• Horst, M. N. and A. N. Walker. 1999. Effects of the Pesticide Morphogenesis and Shell Formation on the Blue Crab Callinectes sapidus.
Journal of Crustacean Biology. 19: 699-707.
• Zulkosky, A. M., J. P. Ruggieri, S. A. Terracciano, B. J. Brownawell, and A. E. McElroy. (2005). Acute Toxicity of Resmethrin, Malathion, and
Methoprene to Larval and Juvenile American Lobsters (Homarus americanus) and Analysis of Pesticide Levels in Surface Waters After
Scourge, Anvil, and Altosid Application. BioOne 24: 795-804.
• World Health Organization. (2001). Piperonyl Butoxide (062). In Pesticide Residues in Food - 2001: Evaluations. Residues, Part 1 (pp. 607-
705).
