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Proposal Cover Sheet
Term: Fall_2011_ Spring _____ Year ______
Instructor Nora Demers
Chris Cannon
Present Year in Education (e.g., freshman, sophomore, etc.): Senior
E-mail Address:
Marine Sciences
Have you identified a research mentor for a senior thesis (if applicable)?
X Yes _____ No.
If yes, please identify.
Name: Dr. Darren Rumbold__________________________
Title of Proposal:
Sex Based Survey of Mercury (Hg) Concentrations in the Blacktip Shark (Carcharhinus
Keywords (3-5) __Mercury Methyl-mercury Sex Sharks Florida________________________
All required portions of the first submission are included _X__ Yes _____ No
I had an external reviewer read the proposal _____ Yes _____ No
If Yes, who ________________________________________ When _______________
I authorize the use of this proposal as an example in future courses __X__ Yes _____ No
The hazards of methyl-mercury (MeHg) consumption in fish and the depleting fisheries have
prompted research to better assess pathways in which mercury (Hg) travels. The high
accumulation of (Hg) >95% in the high trophic status of pelagic sharks and predatory fish are the
basis for this study. This research will entail a thorough comparative analysis of total mercury
(THg) concentrations between the genders of several shark species off the southwest coast of
Florida. In addition, the research will begin to look at (Hg) relationships between gravid females,
their offspring and locations where they may feed while pregnant.
Key Words: Mercury, Methyl-mercury, sharks, sex, Florida
Table of Contents:
I. Project Summary
Page 2
II. Project Description
a. Problem Statement and Introduction
Page 4
b. Research Objectives
Page 6
c. Materials and Methods
Page 7
d. Timetable and Project Management
Page 8
e. Significance of Expected Results
Page 9
III. References Cited
Page 10
IV. Biographical Sketch
Page 11
Sex based Survey of Mercury (Hg) Concentrations in the Blacktip Shark
(Carcharhinus limbatus)
Project Description:
Introduction: Sharks and other predatory fish continue to be a major portion of food resource
for people. Recent studies have shown that many shark species and other high trophic fish
contains unsafe mercury (Hg) concentrations for human consumption (Adams et al. 2003). This
has prompted several government advisories of health risks associated with eating shark and
some fishes above 1.0 ppm of mercury (Adams et al. 2003; Rumbold et al. 2011). Low
concentrations of (Hg) are commonly found in humans as well as many species of animals that
we consume, but it is the high levels of (Hg) that are typically found in predatory fish with high
trophic levels that are of concern (Mahaffy K. R., 2005). Mercury levels in high trophic species
are biomagnified due to slow excretion and high consumption rate of mercury in other fish.
Sharks, such as black tip sharks (C. limbatus), obtain high (Hg) from the predation of other high
trophic fish such as Amberjack, king mackerel and tuna (Cortez 1999; Rumbold et al. 2011). It
has been found that >95% of all the mercury sampled (n=51) in sharks of the southwest coast of
Florida comes in the form of methyl-mercury (MeHg) (Rumbold et al. 2011). In the same study
they found that sharks that had a greater varied diet of crustaceans and other lower trophic
species had lower concentrations of (Hg); as seen in the tiger shark (G. cuvier) (0.188 mg/kg wet
weight) despite its greater size (Rumbold et al. 2011). Another research done found that certain
ages and the sex of sharks can have a significant effect on the concentrations of (Hg); although
the researcher did not conduct a statistical analysis on sex ratio to confirm this (Adams et al.
2003). In the same study the researcher did statistically find high levels of mercury in neonatal
and juvenile sharks that parent female sharks likely pass on high levels of (Hg) through the
maternal fluid exchange (Adams et al. 2003). A study should be done to conclude the lifetime
fluctuations in (Hg) levels in relation to growing sharks or fish. A few of the studies done found
that several species of sharks (Hg) levels border on either side of the safe consumption range of
1.0 ppm (Adams et al. 2003; Rumbold et al. 2011). The study performed by Adams et al. (2003)
found that the mean total mercury levels for juvenile blacktip sharks (C. limbatus) (the shark
with the highest known mercury concentrations off Florida coasts) for females (x=0.87 ppm)
were higher than those for males (x=0.58 ppm). Mercury levels this close to safe consumption
does warrant additional surveys on shark species as well as numerous fishes. Additional concerns
lies with fishing pressures on safe foods to the point of species depletion. If it is found that many
species of high trophic fish and sharks that may be fished or consumed because sex, higher
metabolic rate or a certain age have lower (Hg) levels than the other it would significantly reduce
the selective pressures of overfishing on those species known to have low levels of mercury. This
would allow larger, older species to be left un-fished to continue on the species survival
(Birkland and Dayton 2005). It is my intent to conduct a survey to determine if (Hg) levels in
male sharks are significantly lower than the 1.0 ppm that is required for safe consumption. In
addition, this study will begin to address (Hg) concentrations in maternal fluid transfer as well as
possible correlations in trophic feeding areas.
Research Objective:
The primary function of this research is to identify whether there is a significant difference
between mercury (Hg) concentrations in sharks relating to sex. We do know that (Hg)
concentrations show a linear relationship to that of age and/or size (Adams et al. 2003; Rumbold
et al. 2011). It is also a consideration of this research to probe that the gender may play a key role
in determining trophic feeding levels, feeding areas (potentially finding those areas of higher
mercury loads) and metabolism. Ultimately the source of these researches comes from shark and
other fishes as a dietary food source for human consumption and the health warning advisories
concerning state and federal health officials (Adams et al. 2003; Mahaffey 2005; Rumbold et al
Materials and Methods:
Tissue and sample collection of pelagic sharks will require an I.A.C.U.C protocol to be submitted
for approval prior to sample collecting can start. Key species for this research will include
Blacktip sharks (C. limbatus) because of the potential numbers available for that species and the
need to build a good statistical model. Other species will also be sampled for comparison
however, numbers may be too low for a good statistical analysis; those species may include
Blacknose (C. acronotus), Bull (C. leucas), Tiger (G. cuvier), Hammerhead (S. mokarran); other
species may be included if significant numbers will determine a good statistical use. Materials
will consist of one or more of Florida Gulf Coast University’s boats and necessary safety
equipment. A crew including FGCU professor/s and students will conduct the survey from May
thru October. Fin and Muscle samples will be collected off the coast of Southwest Florida
(Rumbold et al. 2011). Roto-tags, spaghetti tags or a (SPOT) smart position temperature
transmitting satellite tags will be used for marking and tracking of sharks caught during the
research; in addition this will help further studies on migratory patterns and trophic feeding
areas. (SPOT) tags will be used on bull sharks (C. leucas), tiger sharks (G. cuvier) and
Hammerheads (S. mokarran) (Rumbold et al. 2011). Tissue samples will include muscle biopsy
and fin clips. Biopsy samples taken from sharks will be tested using an Hg analyzer (Nippon
Model MA-2000). This analyzer will measure total Hg in an FGCU lab by combustion and atomic
absorption. A GC- Isotope Ratio Mass Spectrometer at UC Davis Stable Isotope Facility (SIF) will
be used to analyze carbon (13C/12C) and nitrogen isotopes of oven dried fin clips. Data will be
statistically analyzed by ANOVA and Kruskal Wallis or Holm-Sidak post-hoc test.
Time Table and Project Management:
The following is a breakdown of approximate time intervals to conclude this research project and
not expected to exceed seven (7) months in duration.
April-Preperations for the study to include
a) Time for all scientific inquires to be met.
b) Scheduling for trip to collection sites off the coast of SW Florida.
c) Check instruments and equipment to be used for the study.
d) Final preperations.
May thru October-Collection of samples
a) Time for trip to location and setup.
b) Collection of samples, measurements and tagging.
c) Storage of samples (frozen)
November- Conclusion of experiment
a) Analysis of samples
b) Run Holm-Sidak post hoc and Anova.
c) Final write of findings, conclusions and further discussions.
Significance of expected results:
The significant dangers mercury (Hg) imposes on humans, animals and the environment
warrants continual assessments and a complete understanding of the trophic transfer of mercury
from prey to predator Currently, several high trophic fish and shark species are listed as not safe
to eat putting considerable strain on other populations due to overfishing and higher numbers of
predatory fish. This research will help by further determining what species that is currently not
safe to consume and put them back on the list of safe fisheries. In addition we will begin to look
further into the transfer of mercury to offspring through maternal fluid transfer and trophic life
history patterns.
References Cited:
1) Adams, D. H., R. H. McMichael, Jr., and G. E. Henderson. 2003. Mercury levels in
marine and estuarine fishes of Florida 1989–2001. Florida Marine Research Institute
Technical Report TR-9. 2nd ed. rev. 57 pp.
2) Beerkircher L. R., Cortes E., Shivji M., Sept 2002, Characteristics of Shark Bycatch on
Pelagic Longlines off the Southeastern United States, 1992-2000
3) Birkland C., Dayton P. K., July 2005 The Importance in Fishery Management of Leaving
the Big Ones, Trends in Ecology and Evolution, Volume 20, Issue 7, Pgs. 356-358
4) Cortes, E. 1999. Standardized diet compositions and trophic levels of sharks. ICES
Journal of Marine Science, 56: 707-717.
5) Evers, D.C., N. Hammerschlag & D. Die. 2008. Mercury levels in Florida sharks: Interim
Report. Report BRI 2008-02, BioDiversity Research Institute, Gorham, Maine.
6) Hueter, R.E., W.G. Fong, G. Henderson, M.F. French, and C.A. Manire. 1995.
Methylmercury concentration in shark muscle by species, size and distribution of sharks
in Florida coastal waters. Water, Air, Soil Pollution, 80: 893-99.
7) Mahaffey K. R., 2005, Mercury Exposure: Medical and Public Health Issues,
Transactions of the American Clinical and Climatology Association, www.
8) Rumbold D. G., Wasno B., Hammerschlag N., Volety A., Nicholson M., (July 2011
Trophic Transfer of Mercury to Sharks Off Southwest Florida
Chris Cannon
2865 14th Avenue NE
Naples, FL 34120
Goals: To work for a professional none profit organization conducting field research and/ or
working with marine life in the field.
Degree: Marine Sciences
Florida Gulf Coast University
May 2013
Supplementary Training:
Master Scuba Diver with certifications in Deep Water, Night and Limited Visibility, Nitrox,
Wreck, Navigation and Stress and Rescue.
Additional certifications include CPR and forklift operators license.
Employment History:
Aquarist: Living Color Enterprises, Ft. Lauderdale FL 2009-2011. Responsible for the
maintenance of private and commercial owned aquariums. Tasks include maintain fish health
and fish stock, check water chemistry and quality, provide customer with the most up to date
information about their fish collection, on call for client questions and emergency.
Biologist: The Aquarium Restaurant, Nashville TN. 2007-2009. Responsibilities include daily
care, diet prep, feeding, record keeping, observation, exhibit design and maintenance, perform
health checks, assist with medical treatments and necropsies, educational tours, facility
maintenance, and dive shows. Senior keeper for entire reptile collection, and in addition take
care of several species of sharks, rays, eels, corals, arthropods and hundreds of marine fishes and
invertebrates. Skills obtained-Attended the 32nd annual herpetological symposium 2008.
Handling of marine fish and invertebrates, water chemistry analysis and treatment, operation of
filtration and pumps. Achievements-implemented multi species exhibit design. Increased
quaruntine space for additional reptiles. Wrote proposals to improve facility esthetics and
increase overall revenue.
Carpenter: Click Carpentry, Nashville TN. 2005-2007. Responsibilities include framing and
construction of new residential homes, additions, decks and patio work. Skills obtained-use of
many electric and pneumatic power tools, levels and framing squares, blue prints and schematic
Kangaroo Keeper: Kangaroo Conservation Center, Dawsonville GA. 2003-04.
Responsibilities include all aspects of daily husbandry, record keeping, medical and health
treatments, tour talks, facility maintenance. Animals under care red, eastern and western gray
kangaroos, Parma wallaby’s, bet tongs, blue winged kookaburras, guenthers dik-dik, burros, and
fallow deer. Skills obtained-educating the general public on the significance of Australian flora,
fauna and marsupial species. Handling, capturing, transferring and treatment of marsupials.
Achievements-Encouraged the addition of Australian reptiles to the facility.
Reptile Keeper/ Maintenance: Catoctin Wildlife Preserve and Zoo, Thurmont MD. 20012003. Responsible for daily husbandry of a variety of reptiles including monitor lizards
(crocodile, nile, asian water, white throat, argus and savannah), venomous snakes (copperhead,
timber rattle, gaboon viper and western diamondback), various large constrictors (anaconda,
reticulated, rock, Burmese pythons and red tailed boas), crocodilians (alligators, caimans and
dwarf caimans) turtles and tortoises (pond, reeves, side-necked and snake-necked turtles, spur
thigh, pancake, Egyptian, leopard, yellow and red foot tortoises) as well as iguanas, skinks, and
geckos. Some North American amphibian species and poison dart frogs. Maintenance
responsibilities include auto mechanics, carpentry, electrical, plumbing, fencing, painting,
landscaping, welding and fabrication, and heavy equipment operator. Skills obtained-handle
large and venomous reptiles and other dangerous animals while following safety and quarantine
guidelines. Writing and keeping of care sheets of all animals under my care. Experience in
animal captures, restraint and transfers.