1. Acknowledgements
References
Conclusions
Discussion
Parasites have a significantly larger biodiversity than most other organisms; in turn they
affect most of the animal kingdom (Keeling 2014; Call 2007). Parasitism is the most
common strategy on the planet. Parasitic organisms can have both positive and negative
effects on the host (Coop and Kyriazakis 1999). Past research has shown that each
parasite-host relationship can be specialized to the specific case. The degree of infection
and the overall health of the host are contributing factors to the ultimate impact of the
infection (Cunjak and McGladdery 1990). In cases like the parasitic infections of the deep
sea Mora moro, the overall prevalence of parasites is not significantly invasive which
causes little damage to the host (Dallares et al. 2014).
Sphyrna tiburo, commonly known as the bonnethead shark is a small coastal shark
species in the hammerhead (Sphyrnidae) family with a known geographic region in the
Tampa Bay area and the Florida Bay area (Cortes and Parsons 1995; Cortes et al. 1996;
Bethea et al. 2007). In a previous study bonnetheads were shown to host heavy
monogenean infections in their gill arches, which led to mortality in aquarium held sharks
(Bullard et al. 2001). However, a sufficient internal parasitic study has not been
conducted in the wild and it was my objective to observe and determine the parasitic
fauna within the bonnethead’s digestive tract. Only through this observation were we be
able to identify and understand the parasite-host relationship and any harm or benefits
associated with hosting these parasites (Dallares et al. 2014).
This research was possible thanks to the Biology department at Florida Southern College,
and the support of Dr. Franks and Dr. Langford. A special thanks to Amy Aycock, Jenna
Karr and Elise Pullen for the help in collection of the sharks for sampling.
Abstract
Introduction
Methods
Results Results (continued)
• 13 sharks captured with gill nets in the Tampa Bay region.
• Euthanized (IACUC protocol #050614) by being immersed in a wooden “knock-out” box
containing tricaine methane-sulfonate (MS-222) at >250mg/L of seawater (AVMA,
2007).
• Labeled with the letters BH and a number corresponding to the order in which they
were caught.
• Pre-caudal length (PCL), fork length (FL), and total length (TL) measured in centimeters
and total body weight measured in kilograms.
• Digestive tract dissected for parasite specimens under a dissection microscope.
• Any parasites found were removed and placed in labeled jars containing a 70% ethanol
solution until mounting (Coop and Kyriazakis 1999).
• Platyhelminth species were stained heavily using Semichon’s acid carmine and de-
stained using an acid-alcohol solution and carried through the ethanol series (70%
ETOH, 85% ETOH, 95% ETOH, and 100% ETOH) for dehydration. Xylene was then
added and the samples were permanently mounted using Permount.
• Nematode species were temporarily mounted on slides using a glycerol mixture`
A survey of the parasitic fauna within the bonnethead shark (Sphyrna
tiburo) in the Tampa Bay region
Bethea, Dana M., Lorraine Hale, John K. Carlson, Enric Cortes, Charles A. Manire, and James
Gelsleichter. “Geographic and Ontogenetic Variation in the Diet and Daily Ration of the
Bonnethead Shark, Sphyrna tiburo, from the Eastern Gulf of Mexico.” Marine Biology
152 (2007): 1009–1020.
Bullard, Stephen A., Salvatore Frasca Jr., and George W. Benz. (2001) “Gill lesions associated
with Erpocotyle tiburonis (Monogenea: Hexabothriidae) on wild and aquarium held
bonnethead sharks (Sphyrna tiburo).” Journal of Parasitology 87 (2007): 972-977.
Coop, R. L., and I. Kyriazakis. “Nutrition–parasite Interaction.” Veterinary Parasitology 84
(1999): 187-204.
Cortes, Enric, and Glenn R. Parsons. “Comparative Demography of Two Populations of the
Bonnethead Shark (Sphyrna tiburo).” Bulletin of Marine Science 58 (1995): 353-367.
Cortes, Enric, Charles A. Manire, and Robert E. Hueter. “Diet, Feeding Habits, and Diel
Feeding Chronology of the Bonnethead Shark, Sphyrna tiburo, in Southwest Florida.”
Aquatic Science 53 (1996): 709-718.
Cunjak, R.A. and S.E. McGladdery. “The Parasite-Host Relationship of Glochidia (Mollusca:
Margaritiferidae) on the Gills of Young-of-the-Year Atlantic Salmon (Salmo salar).”
Canadian Journal of Zoology 69 (1990): 353-358.
Dallares, Sara, Maria Constenla, Francesc Padros, Joan E. Cartes, Montse Sole, and Maite
Carrasson. “Parasites of the Deep-sea fish Mora Moro from the NW Mediterranean Sea
and Relationship with fish Diet and Enzymatic Biomarkers.” Oceanographic Research 92
(2014): 115-126.
Of sharks examined, 9 of 13 had at least one parasite within the digestive tract (overall
infection prevalence = 75%). Examination of the parasites infecting these sharks
revealed 2 separate species, Phoreiobothrium tiburonis, a tapeworm only found in the
mid-spiral valve, and Capillaria sp., a roundworm found in multiple areas of the digestive
tract. Of the 9 infected sharks, only 2 (BH10 and BH14) contained both species of
parasite. The infection prevalence was 66.7% and 23.1% for Phoreiobothrium tiburonis
and Capillaria sp. respectively.
Figure 1 (right): Map of
Florida with a focus (the
red box) on the specific
area of capture, exact
locations denoted by stars
Figure 2 (left): Dissection of
one of the shark specimen
captured.
Table 2: Quantitative statistics including: prevalence, mean intensity, median intensity,
and lower and upper CL’s, and location for each parasite species found within the
sampled sharks.
Figure 3: The mean infection rate by size classes of sampled sharks from the measured
pre-caudal lengths; the size classes with no bar had no infections; no significant
difference was found.
From this research, it can be concluded that the majority of the bonnetheads sampled
have some parasitic infection. This suggests not only that a high proportion of the sharks
in this population are infected, but that the bonnethead itself is host to several different
parasitic species as seen from this study and past studies (Bullard et al. 2001). Many of
the species have yet to be observed and determined. In the future a continuation of this
research needs to be conducted to reach a significant sample size for a more extensive
study, as well as sampling from other areas in and around the Tampa Bay region for
comparison.
• Two species of parasites were identified
• tapeworm: Phereiobothrium tiburonis and nematode: Capillaria sp.
• Statistics show a prevalence of infection at 75.0%
• The tapeworm species is more prevalent than the nematode species in sampled
sharks
• Further research needs to be conducted to gather a significant sample size of sharks
for a more extensive study
• Determine the affects of this specific parasite-host relationship
Although parasites can be found in almost every animal in every habitat, there is little
data on parasites infecting many shark species. This study examined the parasitic
community within the digestive tracts of 13 bonnethead sharks captured between June
and October 2015 in Tampa Bay, Florida. Overall infection prevalence was 0.750 with
two species of parasites found. Phoreiobothrium tiburonis, a tapeworm, was most
common with an infection prevalence of 0.667 while Capillaria sp., a roundworm, had an
infection prevalence of 0.231. These results are the first reported endoparasites from
wild-caught bonnethead sharks in this region. An overall infection prevalence of 75%
suggests that a high proportion of sharks in this population have parasitized digestive
tracts. Further research should focus on increasing the sample size of sharks examined
and also collecting sharks from other areas in and around Tampa Bay.
Figure 4: Microscope photos of Pheoriobothrium tiburonis (top), A-a full body view of the
tapeworm, B-a focus on the scolex and neck with visible hooks, C-a focus on the beginning
of the proglottids area (there is an air bubble in these pictures); and Capillaria sp. (bottom),
D-a larger view of the nematode (not including full body length), F-a closer view of the
head of the nematode.
A B
C
D
F
Samantha Rucker
Biology Department-Florida Southern College
Parasite Prevalence
Mean
Intensity
Median
Intensity
Location Lower CL Upper CL
Phoreiobothrium
tiburonis
0.667 2.00 2.0 Mid Spiral Valve 0.370 0.877
Capillaria sp. 0.231 1.33 1.0
Stomach/Upper
& Lower
Intestine/Mid
Spiral Valve
0.066 0.520