MARINE AND FISHERY SCIENCES 36 (1): 91-100 (2023)

https://doi.org/10.47193/mafis.3612023010101

ABSTRACT. A previous paper in this journal by Shell and Gardner assessed various factors

around the exploration of the Mississippi River by bull sharks (Carcharhinus leucas Müller and

Henle, 1839) based on two twentieth-century occurrences. Recent evidence has suggested one of

these occurrences is a probable hoax. Here, we provide a correction to our earlier paper, as well as

additional comments on extralimital euryhaline vertebrates in the Mississippi River system, the

environmental and historical contexts for their exploration into riverine systems, and suggest steps

for any future effort to detect the usage of these river systems by bull sharks.

Key words: Freshwater elasmobranchs, extralimital, historic records, hoax.

Actualizaciones sobre las supuestas ocurrencias de tiburón toro (Carcharhinus leucas) en la

cuenca superior del Río Mississippi de América del Norte

RESUMEN. En un artículo anterior de Shell y Gardner en esta revista, se evaluaron varios fac-

tores en torno a la exploración del Río Mississippi por parte de los tiburones toro (Carcharhinus leu-

cas Müller y Henle, 1839) basados en dos sucesos del siglo XX. La evidencia reciente sugiere que

una de estas ocurrencias es un probable engaño. Brindamos aquí una corrección a nuestro artículo

anterior, así como comentarios adicionales sobre los vertebrados eurihalinos extralimitantes en el

sistema del Río Mississippi, los contextos ambientales e históricos para su exploración en los siste-

mas fluviales, y sugerimos los pasos para cualquier esfuerzo futuro en detectar el uso de estos sis-

temas fluviales por los tiburones toro.

Palabras clave: Elasmobranquios de agua dulce, extralimitantes, registros históricos, engaño.

A short summary of research into the history of bull shark (Carcharhinus

leucas Müller and Henle, 1839) occurrences in the upper Mississippi River

was published in this journal in 2021. It noted that, despite an apparent lack

of information from the fossil and archeological records and pre-20th century

historical accounts, bull sharks infrequently explore the Mississippi River

Channel in the vicinity of the city of St. Louis, Missouri (USA) (Shell and

Gardner 2021). We sought to examine this due to Mississippi River bull

sharks being an oft-cited factoid, though assessments of these statements

within the scholarly literature or attempts to understand this behavior in the

Mississippi River such as causes or frequency were virtually non-existent.

*Correspondence:

ngardner@mail.wvu.edu

Received: 18 January 2022

Accepted: 5 August 2022

ISSN 2683-7595 (print)

ISSN 2683-7951 (online)

https://ojs.inidep.edu.ar

Journal of the Instituto Nacional de

Investigación y Desarrollo Pesquero

(INIDEP)

This work is licensed under a Creative

Commons Attribution-

NonCommercial-ShareAlike 4.0

International License

Marine and

Fishery Sciences

MAFIS

NOTE

Updates on putative bull shark (Carcharhinus leucas) occurrences in the

upper Mississippi River Basin of North America

RYAN SHELL1, NICHOLAS GARDNER2, * and ROBERT A. HRABIK3

1Department of Vertebrate Paleontology, Cincinnati Museum Center, 1301 Western Ave, 45203 - Cincinnati, USA. 2Mary F. Shipper Library,

Potomac State College, West Virginia University, 101 Fort Avenue, 26726 - Keyser, USA. 3Missouri Department of Conservation, Oak Ridge,

USA. ORCID Ryan Shell https://orcid.org/0000-0001-6634-3127, Nicholas Gardner https://orcid.org/0000-0002-5278-7541

The International Shark Attack File (ISAF) notes

that bull sharks are the third most common shark

species to be implicated in an unprovoked nega-

tive encounter, accounting for 12.7% of all inci-

dents on record; with the top two species being

white sharks (Carcharodon carcharias Linnaeus,

1758) with 37.0% and tiger sharks (Galeocerdo

cuvier Péron and Lesueur, 1822) with 14.6%.

Like many shark species, bull sharks are a declin-

ing species, previously listed as ‘near threatened’

(Cascio 2017) but reassessed as vulnerable in

2020 (Rigby et al. 2021). Public perception of

bull sharks as a killing machine capable of

exploring deep into freshwater habitats have not

served the species well in popular media and are

harmful to conservation initiatives. This served as

an additional motivation to demystify bull shark

movement in the Mississippi River Basin.

The evidence for this centered on occurrences

from Alton, Illinois (USA) and the Rush Island

power station near Festus, Missouri (USA). The

former case is well-established in the ichthyolog-

ical literature (Thomerson et al. 1977) and has

never been satisfactorily falsified despite a recent

claim in a newspaper that the shark was bought at

a fish market in St. Louis (Cousins 2021).

Thomerson et al. (1977) provided sufficient argu-

ments against such a possibility and, despite

being a local oddity for the past 85 years and part

of the ichthyological literature for the past 45

years, no such first-hand evidence against its

veracity has ever been brought forward.

The latter case from Rush Island was based on

limited evidence which we noted in our paper. At

the time, it appeared credible, and was cited in the

literature (Burr et al. 2004, p. 249: ‘Indeed,

another bull shark was taken in the 1990s off the

screen of a power plant intake canal. This report

does not appear to be the product of a hoax, but

there is little information other than a newspaper

report’), and was believed to be true by fish and

wildlife professionals that the authors had spoken

with. Our paper was well-received in the media,

both by regional and national news outlets, was

downloaded from the journal homepage more

than 800 times, and was recently cited by another

scientist documenting freshwater occurrences of

bull sharks (Gausmann 2021). Our research

spurred an in-progress manuscript by one of us

(NG) to document hoaxes and misidentifications

of sharks in freshwater and it is not without irony

that we must now admit that we have accidentally

propagated such a case.

Around the time our manuscript was undergo-

ing review, RH independently examined the Rush

Island occurrence for his in-progress revision of

‘The Fishes of Missouri’. RH published his find-

ings in a journal with limited regional scope the

same month as our paper (Hrabik 2021). He

reported that the 96 cm long recovered specimen

was not a bull shark, but an Atlantic sharpnose

shark (Rhizoprionodon terraenovae Richardson,

1836). It is not unreasonable to conclude that the

Missouri Department of Conservation ichthyolo-

gist who first identified the shark could have con-

fused the specimen as juvenile requiem sharks

grossly resemble each other (Figure 1) and may

have made the presumption given its appearance

in freshwater that it was a bull shark considering

their known usage of riverine systems and knowl-

edge of the Alton occurrence. Confusion between

species of the Carcharhinidae, a wide ranging

family with at least 60 extant species, especially

at different life stages is not uncommon even for

ichthyologists (Branstetter 1982; Dosay-Akbulut

2008; Smart et al. 2016). This said, however,

Atlantic sharpnose sharks have never been report-

ed from riverine ecosystems even though this

species utilizes estuaries as nursery grounds like

many other requiem sharks (Ebert et al. 2021).

This led Hrabik (2021) to conclude the Rush

Island occurrence is a case of an improperly

dumped individual if not an outright hoax, rather

than a valid occurrence. RH brought our attention

to his work and we reached out to wildlife profes-

sionals in states bordering the lower part of the

Upper Mississippi River Basin to gather addition-

al information. After doing so, we felt Hrabik

92 MARINE AND FISHERY SCIENCES 36 (1): 91-100 (2023)

(2021) had established evidence as to why the

supposed bull shark was misidentified by prior

wildlife professionals and provided sufficient

arguments as to why it could not have naturally

appeared where it was found, even if there are

still many unanswerable questions such as who

perpetrated this likely hoax and their motivations.

However, the ability of the bull shark to penetrate

rivers as far inland in North America as far as

Alton, Illinois as well as its similar behavior in

other riverine systems worldwide apparently

makes it a subject of erroneous reports and

encourages false reports (compare Dukes 2016).

The discrediting of the Rush Island occurrence

means that the only known record of a bull shark

in the upper Mississippi River Basin was reported

from Alton, Illinois before the installation of the

Mississippi’s current system of locks and dams.

The fact that none can be verified from a time

after the installation of locks strongly suggests

that the bull shark’s upriver range has been limit-

ed by their installation for much of the 20th cen-

tury, so we must now reject our earlier proposal in

Shell and Gardner (2021) that unobservable pas-

sage through the most southward locks and dams

could have occurred to explain the 1995 occur-

rence. Regular reports of marine shark remains

dumped in improbable places further hampers

research into the history of this presumed habitat

loss (Gausmann 2021). We are also left with addi-

tional questions about the 1937 occurrence– was

this an isolated event or a previously more wide-

spread behavior? If the evidence is lacking for the

latter, then what factors led to this anomalous

event?

A north-south migration following coastlines

has been observed in bull sharks. Along the east

coast of the United States it is observed that bull

sharks tend to summer in northern latitudes and

then move further south with cooler waters (Cas-

tro 2011). They commonly migrate as far north as

the Chesapeake Bay or even off the coast of New

England, which is further north latitudinally than

Alton, Illinois (38.8906° N latitude). These north-

ward migrations when in estuarine environments

can lead to riverine explorations such as the

SHELL ET AL.: UPDATES ON PUTATIVE BULL SHARK OCCURRENCES

Figure 1. Supposed bull shark recovered from the Rush Island power station near Festus, Missouri, from 1995, properly identi-

fied as an Atlantic sharpnose shark Rhizoprionodon terraenovae by Hrabik (2021). Photograph by Michael Fuhr (Mis-

souri Department of Conservation) provided to RH.

reports of sharks in the Patuxent and Potomac

Rivers from the Chesapeake Bay (Alderman

2014; Hedgpeth 2015; Chason 2018) or the more

infamous, but not definitively proven example in

Matawan Creek from the Raritan Bay in New Jer-

sey in 1916 (McCormick 1963; see also Gaus-

mann 2021). This may help contextualize the

1937 occurrence.

Other euryhaline marine vertebrates are capa-

ble of widespread dispersals into freshwater sys-

tems, and the environmental influences on this

behavior are complex (currents, depth, salinity,

temperature, food availability, etc.). Understand-

ing what may represent rare or previously unob-

served behavior versus actions of wayward indi-

viduals will depend on confirming the frequency

of valid observations. Other brackish or marine

vertebrates for which osmoregulatory competen-

cy is not a factor in freshwater survivability have

demonstrated surprising long-distance dispersals

into riverine systems.

One notable instance of a wayward euryhaline

marine vertebrate in the lower Mississippi River

Basin was that of a 3 m long West Indian manatee

(Trichechus manatus Linneaus, 1758) (Mam-

malia: Sirenia) which wandered more than

1,200 km upriver to near Memphis, Tennessee

(USA) (Manatee... 2006; Romero 2006). First

spotted on October 23, 2006 only to ultimately be

found dead 49 days later, the individual evaded

detection by teams of federal and state wildlife

and law enforcement professionals as well as an

independent private team from SeaWorld Orlan-

do who utilized aerial and boat-based spotting,

side-scan sonar, and FLIR imaging (Officials...

2006). Though no cause of death was reported,

hypothermia seems most probable and starvation

less likely given healthy sirenians may last up to

seven months without depleting their fat reserves

(Best 1983) and variation in water salinity is not

a stress inducer for manatees when invading

riverine systems (Ortiz et al. 1998; Callejas-

Jiménez et al. 2021), unlike other marine mam-

mals (Pemberton 2011). This large-scale move-

ment upriver may have taken 36-44 days to com-

plete based on modest estimations of migratory

behavior in T. manatus (27.3-33.5 km d-1 typical-

ly over 10-15 days according to Deutsch et al.

2003).

Consequently, if such a large and otherwise

conspicuous species such a manatee, for which

salinity is not an ecological barrier, can navigate

this far upriver without detection and evade con-

centrated human effort to locate it, it raises ques-

tions as to the potential to evade human detection

by smaller species such as bull sharks. These

sharks also engage in difficult to observe behav-

iors in freshwater and brackish systems, such as

swimming low in the water column when moving

upriver during the daytime (Heupel et al. 2010), a

behavior retained during migrations (Daly et al.

2014).

Similar accounts of long-range dispersals

upriver in the lower Mississippi River Basin have

been made by other typically brackish or offshore

elasmobranchs, such as dasyatids (McCormick

1963; Brown 2010), and common freshwater

species which frequently grow larger than bull

sharks (alligator gars, blue catfishes, Gulf stur-

geon, and paddlefishes) often move up and down

the Mississippi River without being detected until

they are caught on a line or in a net (Broom 2015)

(Figure 2).

Despite the near lack of information in the

upper Mississippi River Basin, archeological

reports indicate an indigenous interest in the

recovery of non-fossil shark material in central

Louisiana (USA) from approximately 1,300

years before present (though extra regional trade

cannot be ruled out to explain its presence)

(Springer 1980). Furthermore, a supposed white

shark was captured in Natchez, Mississippi

(USA) in 1829 more than 500 km up-river from

the Gulf (Another… 1829), though the size of

the animal and its freshwater location are more

suggestive of a bull shark. Its identification as C.

carcharias is probably more reflective of the

limited ichthyological knowledge of that time

94 MARINE AND FISHERY SCIENCES 36 (1): 91-100 (2023)

(Carcharhinus leucas was not yet described until

1839). This is much further than other reported

cases of freshwater penetrations by bull sharks in

the Mississippi River system by Gunter (1938) at

300 km up-river for Simmesport, Louisiana and

440 km up-river for Jonesport, Louisiana,

although Matich et al. (2020) gave information

on a bull shark record from 950 km up-river in

the Red River, Louisiana, Arkansas, Oklahoma,

and Texas. Thomerson et al. (1977) cited Gunter

(1938) and observed ‘[Bull sharks] undoubtedly

occur much more commonly in the lower Missis-

sippi than the scientific record discloses, and the

wonder is that they have not been reported much

farther up the river than they have’ (p. 168). It

would therefore seem that the exploration, even

if not long term habitation, of North American

rivers, as a behavior, has a deep Holocene history

in bull sharks, and the presence of their DNA in

the Alabama-Tensaw River of Alabama (USA) as

recently as 2018 (Drymon et al. 2021) indicates

that this pattern is ongoing in the lower reaches

of the Mississippi River Basin, exploration in

other rivers along the Atlantic and Gulf coastal

plains is documented though not fully under-

stood. The same applies to sustained migrations

of the species in coastal and oceanic environ-

ments (Carlson et al. 2011; Daly et al. 2014; Lea

et al. 2015). For now, however, evidence of bull

shark exploration into the upper Mississippi

River Basin is given only by a singular occur-

rence, and it is possible river impediments pre-

vent bull sharks (and other anadromous fish) to

move into the upper stretches of the Mississippi

River. If this occurrence represents anomaly

rather than evidence of a more common, yet dif-

ficult to detect, behavior, reasons for that conclu-

sion have not been explained to date, and the

post-1937 manmade impediments on the river

may have impeded subsequent occurrences as

SHELL ET AL.: UPDATES ON PUTATIVE BULL SHARK OCCURRENCES

Figure 2. Relative sizes of wayward individuals of marine species (inside yellow box) compared with large regular freshwater

or brackish species of the Lower Mississippi River Basin and the average size of male and female bull sharks (Car-

charhinus leucas Müller and Henle, 1939). Silhouettes courtesy of Phylopic (http://phylopic.org) unless noted otherwise

in acknowledgements. Sizes for species derived from common lengths reported in FishBase (http://www.fishbase.org)

or Animal Diversity Web (https://animaldiversity.org). The average length of the bull shark was derived from Ebert et

al. (2021: 535).

American alligator

Bull shark

Blue catﬁsh

Paddleﬁsh

Alligator gar

Gulf sturgeon

Memphis

stingray

Memphis

manatee

Alton bull shark

Rush Island shark

2 m

suggested by Thomerson et al. (1977). However,

historic reports of bull shark records from further

large streams of the world such as the Tigris

River, Iraq (Günther 1874) and the Amazon

River in Brazil, Colombia, and Peru (Thorson

1972) suggest that long-distance movements of

bull sharks up to thousands of kilometers are

exceptional and rare events, and the majority of

immature bull sharks presumably utilize the

lower reaches of rivers.

Increased surveillance for large predatory fish

in the lower Mississippi River Basin may help to

better understand exploration of riverine systems

by bull sharks and other marine fishes. This

increased surveillance could take the form of

environmental DNA monitoring (such as that of

Drymon et al. 2021), through the tagging of indi-

vidual bull sharks in nearshore ecosystems which

could reveal riverine exploration, or a wider pop-

ulation survey of fishes in near shore and

upstream localities. The authors encourage an

extensive investigation of the Mississippi River

Basin as a potential nursery area for bull sharks,

as the few records from this river systems indi-

cate this function, and moreover, the influence of

anthropogenic impact such as water pollution on

the fish fauna that inhabit this system. Currently,

the Mississippi River must be valued as a data-

poor area regarding the occurrences of sharks,

and the importance of this river system for elas-

mobranchs is unclear.

While the behavior of bull sharks in estuarine

and riverine environments has been the subject of

previous studies (Heupel and Simpfendorfer

2008; Ortega et al. 2009; Heupel et al. 2010; Cur-

tis et al. 2011; Curtis et al. 2013), it is important

to continue to monitor for behavioral changes

associated with climate change for which temper-

ature increases and sea level rises are predicted to

alter or increase the frequency in which bull

sharks may utilize these near-coastal brackish to

freshwater environments (Heithaus et al. 2009;

Matich et al. 2020). Recent studies have already

demonstrated that given their reliance on these

ecosystems as nurseries, bull sharks are suscepti-

ble to climate change-driven alterations of estuar-

ies (Niella et al. 2022). There is already evidence

for these behavioral shifts in the global fossil

record of bull sharks dating back at least as far as

the Pleistocene (Lopes et al. 2020) and oppor-

tunistic exploration by bull sharks into man-made

waterways are well documented worldwide

(Alive... 1896; Montoya and Thorson 1982;

Werry et al. 2012; Curtis et al. 2013). There are

increased reports of bull sharks in these environ-

ments globally (Gausmann 2021; Hasan et al.

2021; Gausmann and Hasan 2022), though it

could be due to increased effort to gather these

records rather than a behavioral shift.

Additionally, the widespread digitization of

historical records such as newspapers or archival

image and manuscript collections have provided

a powerful new tool in understanding the past

geographic distributions and relative abundance

of fishes (Cochran 2007; McClenachan 2009;

Cochran and Elliott 2012; Cochran 2015; Palsson

and Astthorsson 2017; Disspain et al. 2018;

Keevin and Lopinot 2019; Bom et al. 2020; Brevé

et al. 2022). However, it is crucial to acknowl-

edge that unusual cases such as these must be

approached with greater scrutiny and a higher

standard of evidence. While many euryhaline

elasmobranchs are known to invade (if only

ephemerally) freshwater habitats, verification of

riverine elasmobranchs in North America would

ideally happen through securing voucher speci-

mens (which was not done in the Rush Island

occurrence) and improved photographic tech-

niques that would permit identification (as thank-

fully had been done for the Rush Island occur-

rence). In the event of reported occurrences of

euryhaline elasmobranchs invading far into river-

ine systems (such as Brown 2010), if wildlife pro-

fessionals can take steps to document these spec-

imens clearly even if voucher specimens cannot

be obtained, it will be helpful for illuminating our

understanding how sharks and other marine fish-

es utilize these systems, in this case the widely

96 MARINE AND FISHERY SCIENCES 36 (1): 91-100 (2023)

branched Mississippi River system. Finally, when
accounts must be taken from news reports online,
we urge the use of web archiving tools which cap-
ture and preserve those records, such as Archive
Today (https://archive.today) which we have used
in this paper. These occurrences are often report-
ed in the popular press or through social media
which often exist online ephemerally, possibly
anywhere from 40-100 days without being updat-
ed or modified (LaFrance 2015).
ACKNOWLEDGEMENTS
The silhouettes in Figure 2 were created by
PhyloPic contributors (Lily Hughes, Maija Kar-
ala, M. Kolmann, Duane Raver, Nick Schooler,
Vince Smith) except the paddlefish (Polyodon
spathula) which was modified from a drawing by
Yaroslava Alekseeva and the American alligator
(Alligator mississippiensis) which was CC-0
licensed and created by Mohamed Hassan. We
thank the three anonymous reviewers whose
feedback on the first submission of this manu-
script encouraged us to expand our thoughts and
the anonymous reviewer whose feedback on this
manuscript’s resubmission helped us greatly
improve the quality of this manuscript.
REFERENCES
ALDERMAN J. 2014 Sep 12. Bull sharks swim in
Potomac waters. WAMU 88.5 (Washington,
DC). https://archive.ph/Bp6dC [archived web-
page].
ALIVE with sharks. 1896 Nov 29. The Commer-
cial Appeal (Memphis, TN); 11. https://archi
ve.ph/k5Kjf [archived webpage].
ANOTHER shark, (Squalus Carcharies, or Great
White Shark,) three feet and two inches in
length, has been taken in the Mississippi,
opposite the residence of John Siegmund,
Esq., about two miles below this city. 1829
Aug 27. Southern Galaxy (Natchez, MS); 3.
https://archive.ph/AfV6A [archived web-
page].
BEST RC. 1983. Apparent dry-season fasting in
Amazonian manatees (Mammalia: Sirenia).
Biotropica. 15 (1): 61-64. DOI: https://doi.org
/10.2307/2388000
BOM RA, VAN DE WATER M, CAMPHUYSEN KCJ,
VAN DER VEER HW,  VAN LEEUWEN A. 2020.
The historical ecology and demise of the icon-
ic Angelshark Squatina squatina in the south-
ern North Sea. Mar Biol. 167: 91. DOI:
https://doi.org/10.1007/s00227-020-03702-0
BREVÉ NWP, NAGELKERKE LAJ, BUIJSE AD, VAN
TUIJIN TJ, MURK AJ, WINTER HV, LENDERS
HJR. 2022. Historical reconstruction of stur-
geon (Acipenser spp.) spatiotemporal distribu-
tion and causes for their decline in North-
Western Europe. Biodivers Conserv. DOI:
https://doi.org/10.1007/s10531-022-02381-1
BROOM B. 2015 Jun 6. Mississippi’s river mon-
sters. Clarion-Ledger (Jackson, MS). https://
archive.ph/Slpy6 [archived webpage].
BROWN L. 2010 Aug 7. Memphis woman photo-
graphs stingray in Mississippi River. Action
News 5 (Memphis, TN). https://archive.fo/No
36T [archived webpage].
BURR BM, BASILE CM, ADAMS GL, NICHOLSON
MC. 2004. Exotic aquatic and terrestrial ani-
mals in the Hoosier-Shawnee ecological
assessment area. In: THOMPSON FR, editor.
The Hoosier-Shawnee Ecological Assessment.
St. Johns (MI): U.S. Department of Agricul-
ture, Forest Service, North Central Research
Station. p. 236-267.
CALLEJAS-JIMÉNEZ ME, ALCÉRRECA-HUERTA JC,
MORALES-VELA B, CARRILLO L. 2021. Spatial
and seasonal variations in surface water tem-
perature and salinity in the Mexico-Belize
riverine estuary: possible comfort conditions
for manatees? Mar Mamm Sci. 37: 1454-
1474. DOI: https://doi.org/10.1111/mms.12838
97
SHELL ET AL.: UPDATES ON PUTATIVE BULL SHARK OCCURRENCES

CARLSON JK, RIBERA MM, CONRATH CL, HEUPEL
MR, BURGESS GH. 2010. Habitat use and
movement patterns of bull sharks Carcharhi-
nus leucas determined using pop-up satellite
archival tags. J Fish Biol. 77: 661-675. DOI:
https://doi.org/10.1111/j.1095-8649.2010.02
707.x
CASCIO K. 2017. Carcharhinus leucas [Internet].
Animal diversity web. Ann Arbor (MI): Uni-
versity of Michigan. https://archive.ph/kRZP9
[archived webpage].
CASTRO JI. 2011. The sharks of North America.
New York (NY): Oxford University Press.
CHASON R. 2018 Aug 15. After 42 years of fish-
ing, he’s never seen anything like this 310-
pound bull shark. Washington Post (Washing-
ton, DC). https://archive.ph/yedRS [archived
webpage].
COCHRAN PA. 2007. Additional notes on the his-
tory of American eels (Anguilla rostrata) in
the Upper Midwest. American Currents. 33
(3): 21-22. http://www.nanfa.org/ac/notes-
american-eels-upper-midwest.pdf.
COCHRAN PA. 2015. Big fish stories: analysis of
historical newspaper data on size of lake Stur-
geon (Acipenser fulvescens) in the Lake
Michigan Basin. Mich Acad. 42 (1): 26-39.
DOI: https://doi.org/10.7245/0026-2005-42.1.
26
COCHRAN PA, ELLIOTT RF. 2012. Newspapers as
sources of historical information about lake
sturgeon (Acipenser fulvescens Rafinesque,
1817). Arch Nat Hist. 39: 136-146. DOI:
https://doi.org/10.3366/anh.2012.0066
COUSINS S. 2021 Jul 15. The real story behind
Alton’s bull shark legend. Telegraph (Alton,
IL). https://archive.fo/ykPB6 [archived web-
page].
CURTIS TH, ADAMS DH, BURGESS GH. 2011. Sea-
sonal distribution and habitat association of
bull sharks in the Indian River Lagoon, Flori-
da: a 30-year synthesis. Trans Am Fish Soc.
140: 1213-1226. DOI: https://doi.org/10.1080/
00028487.2011.618352
CURTIS TH, PARKYN DC, BURGESS GH. 2013. Use
of human-altered habitats by bull sharks in a
Florida nursery area. Mar Coast Fish. 5: 28-
38. DOI: https://doi.org/10.1080/19425120.20
12.756438
DALY R, SMALE MJ, COWLEY PD, FRONEMAN PW.
2014. Residency patterns and migration
dynamics of adult bull sharks (Carcharhinus
leucas) on the east coast of southern Africa.
PLoS ONE. 9 (10): e109357. DOI: https://doi.
org/10.1371/journal.pone.0109357
DEUTSCH CJ, REID JP, BONDE RK, EASTON DE,
KOCHMAN HI, O’SHEA TJ. 2003. Seasonal
movements, migratory behavior, and site
fidelity of West Indian manatees along the
Atlantic Coast of the United States. Wildl
Monogr. 151: 1-79. https://www.jstor.org/
stable/3830830
DISSPAIN MCF, ULM S, DRAPER N, NEWCHURCH J,
FALLON S, GILLANDERS BM. 2018. Long-term
archaeological and historical archives for mul-
loway, Argyrosomus japonicus, populations in
eastern South Australia. Fish Res. 205: 1-10.
DOI: https://doi.org/10.1016/j.fishres.2018.
03.009
DOSAY-AKBULUT M. 2008. The phylogenetic rela-
tionship within the genus Carcharhinus. C R
Biol. 331 (7): 500-509. DOI: https://doi.org/
10.1016/j.crvi.2008.04.001
DRYMON J, SCHWEISS K, SEUBERT E, LEHMAN R,
DALY-ENGEL T, PFLEGER M, PHILLIPS, N. 2021.
Swimming against the flow-environmental
DNA can detect bull sharks (Carcharhinus
leucas) across a dynamic deltaic interface.
Ecol Evol. 11: 22-28. DOI: https://doi.org/10.
1002/ece3.7101
DUKES J. 2016. Getting to the bottom of Lake
Michigan’s legendary ‘shark attack’.
[accessed 2022 July 26]. https://www.wbez.
org/stories/getting-to-the-bottom-of-lake-
michigans-legendary-shark-attack/939d4ecf-
2dcc-4450-9ba7-5ca51a106e82.
EBERT DA, DANDO M, FOWLER S. 2021. Sharks of
the world: a complete guide. Princeton (NJ):
98 MARINE AND FISHERY SCIENCES 36 (1): 91-100 (2023)

Princeton University Press. DOI: https://doi.
org/10.1515/9780691210872
GAUSMANN P. 2021. Synopsis of global fresh and
brackish water occurrences of the bull shark
Carcharhinus leucas Valenciennes, 1839
(Pisces: Carcharhinidae), with comments on
distribution and habitat use. Integr Syst:
Stuttgart Contr Nat Hist. 4 (1): 55-213. DOI:
https://doi.org/10.18476/2021.423083
GAUSMANN P, HASAN V. 2022. New inland
records of the bull shark Carcharinus leucas
from Sumatra, Indonesia. Mar Fish Sci. 35
(3): 437-444. DOI: https://doi.org/10.47193/
mafis.3532022010905 
GUNTER G. 1938. Notes on invasion of fresh
water by fishes of the Gulf of Mexico, with
special reference to the Mississippi-Atcha-
falaya River system. Copeia. 1938 (2): 69-72.
DOI: https://doi.org/10.2307/1435693
GÜNTHER A. 1874. A contribution to the fauna of
the River Tigris. Ann Mag Nat Hist. 4 (14):
36-38.
HASAN V, S AMITRA D, WIDODO MS, GAUSMANN P.
2021. A new inland record of the bull shark
Carcharhinus leucas (Müller & Henle 1839)
from peninsular Malaysia. Sains Malays. 50
(10): 3153-3158. DOI: https://doi.org/10.175
76/jsm-2021-5010-26
HEDGPETH D. 2015 Sep 4. 8-foot-long bull shark
caught in the Potomac River. Washington Post
(Washington, DC). https://archive.ph/9oIIw
[archived webpage].
HEITHAUS MR, DELIUS BK, WIRSING AJ, DUNPHY-
DALY MM. 2009. Physical factors influencing
the distribution of a top predator in a subtrop-
ical oligotrophic estuary. Limnol Oceanogr.
54: 472-482. DOI: https://doi.org/10.4319/lo.
2009.54.2.0472
HEUPEL, MR, SIMPFENDORFER CA. 2008. Move-
ment and distribution of young bull sharks
Carcharhinus leucas in a variable estuarine
environment. Aquat Biol. 1: 277-289. DOI:
https://doi.org/10.3354/ab00030
HEUPEL MR, YEISER BG, COLLINS AB, ORTEGA L,
SIMPFENDORFER CA. 2010. Long-term pres-
ence and movement patterns of juvenile bull
sharks,  Carcharhinus leucas, in an estuarine
river system. Mar Freshwat Res. 61: 1-10.
DOI: https://doi.org/10.1071/MF09019
HRABIK R. 2021. 1995 Report of a shark in a
power plant return flow channel at Rush
Island, Mississippi River, Missouri, deter-
mined to be a hoax. American Currents. 46
(3): 3. https://archive.org/details/ac-46.3.draft
-1-for-editors [archived copy].
KEEVIN TM, LOPINOT NH. 2019. Historical record
of an alligator gar, Atractosteus spatula
(Lacépède, 1803), captured on the floodplain
of the Middle Mississippi River at Columbia,
Illinois, USA. J Appl Ichthyol. 35: 871-875.
DOI: https://doi.org/10.1111/jai.13925
LAFRANCE A. 2015 Sep 30. How many websites
are there? The Atlantic. https://archive.ph/y
TL1q [archived webpage].
LEA JSE, HUMPHRIES NE, CLARKE CR, SIMS DW.
2015. To Madagascar and back: long-distance,
return migration across open ocean by a preg-
nant female bull shark Carcharhinus leucas. J
Fish Biol. 87: 1313-1321. DOI: https://doi.
org/10.1111/jfb.12805
LOPES RP, PEREIRA JC, DILLENBURG SR, TATUMI
SH, YEE M, FIGUEIREDO AMG, KINOSHITA A,
BAFFA O. 2020. Late Pleistocene-Holocene
fossils from Mirim Lake, Southern Brazil, and
their paleoenvironmental significance: I - ver-
tebrates. J South Am Earth Sci. 100: 102566.
DOI: https://doi.org/10.1016/j.jsames.2020.
102566
MANATEE examined at Memphis Zoo. 2006 Dec
12. Action News 5 (Memphis, TN). https://
archive.fo/dtBoe [archived webpage].
MATICH P, NOWICKI RJ, DAVIS J, MOHAN JA,
PLUMLEE JD, STRICKLAND BA, TINHAN TC,
DAVID WELLS RJ, FISHER M. 2020. Does prox-
imity to freshwater refuge affect the size struc-
ture of an estuarine predator (Carcharhinus
leucas) in the north-western Gulf of Mexico?
Mar Freshwat Res. 71: 1501-1516. DOI:
99
SHELL ET AL.: UPDATES ON PUTATIVE BULL SHARK OCCURRENCES

https://doi.org/10.1071/MF19346
MCCLENACHAN L. 2009. Historical declines of
goliath grouper populations in South Florida,
USA. Endang Species Res. 7: 175-181. DOI:
https://doi.org/10.3354/esr00167
MCCORMICK H. 1963. Shadows in the sea: the
sharks, skates and rays. Philadelphia (PA):
Chilton Books. [accessed 2022 July]. https://
archive.org/details/shadowsinseashar00mcco. 
MONTOYA RV, THORSON TB. 1982. The bull shark
(Carcharhinus leucas) and largetooth sash
(Pristis perotteti) in Lake Bayano, a tropical
man-made impoundment in Panama. Environ
Biol Fishes. 7: 341-347. DOI: https://doi.org/
10.1007/BF00005568
NIELLA Y, R AOULT V, G ASTON T, GOODMAN K,
HARCOURT R, PEDDEMORS V,  S MOOTHEY AF.
2022. Reliance of young sharks on threatened
estuarine habitats for nutrition implies suscep-
tibility to climate change. Estuar Coast Shelf
Sci. 268: 107790. DOI: https://doi.org/10.10
16/j.ecss.2022.107790
OFFICIALS: “Intense hunt” for Memphis manatee
has concluded. 2006 Oct 25. Action News 5
(Memphis, TN). https://archive.fo/nhuwb
[archived webpage].
ORTEGA LA, HEUPEL MR, VAN BEYNEN P, MOTTA
PJ. 2009. Movement patterns and water quali-
ty preferences of juvenile bull sharks (Car-
charhinus leucas) in a Florida estuary. Envi-
ron Biol Fishes. 84: 361-373. DOI: https://doi.
org/10.1007/s10641-009-9442-2
ORTIZ RM, WORTHY AJ, MACKENZIE DS. 1998.
Osmoregulation in wild and captive West
Indian manatees (Trichechus manatus). Physi-
ol Biochem Zool. 71: 449-457. DOI: https://
doi.org/10.1086/515427
PALSSON J, ASTTHORSSON OS. 2017. New and his-
torical records of the ocean sunfish Mola mola
in Icelandic waters. J Fish Biol. 90: 1126-
1132. DOI: https://doi.org/10.1111/jfb.13237
PEMBERTON M. 2011 Oct 6. Orcas make rare trip
into fresh water in Alaska. The Seattle Times
(Seattle, WA). https://archive.ph/I3gfJ
100 MARINE AND FISHERY SCIENCES 36 (1): 91-100 (2023)
[archived webpage].
RIGBY CL, ESPINOZA M, DERRICK D, PACOUREAU
N, DICKEN M. 2021. Carcharhinus leucas. The
IUCN Red List of Threatened Species 2021:
e.T39372A2910670. DOI: https://dx.doi.org/
10.2305/IUCN.UK.2021-2.RLTS.T39372A29
10670.en
ROMERO A. 2006 Nov 13. Manatee found in Mis-
sissippi River, then lost, remains mystery to
experts. Jonesboro Sun (Jonesboro, AR); A6.
https://academicworks.cuny.edu/bb_pubs/957/.
SHELL R, GARDNER N. 2021. Movement of the
bull shark (Carcharhinus leucas) in the upper
Mississippi River Basin, North America. Mar
Fish Sci. 34 (2): 263-267. DOI: https://doi.org/
10.47193/mafis.3422021010607
SMART JJ, CHIN A, BAJE L, GREEN ME, APPLE-
YARD SA, TOBIN AJ, SIMPFENDORFER CA,
WHITE WT. 2016. Effects of including
misidentified sharks in life history analyses: a
case study on the grey reef shark Carcharhinus
amblyrhynchos from Papua New Guinea.
PLoS ONE. 11 (4): e0153116. DOI: https://doi
.org/10.1371/journal.pone.0153116
SPRINGER JW. 1980. An analysis of prehistoric
food remains from the Bruly St. Martin Site,
Louisiana, with a comparative discussion of
Mississippi Valley faunal studies. Mid Cont J
Archaeol. 5: 193-223. https://www.jstor.org/
stable/20707857.
THOMERSON JE, THORSON TB, HEMPEL RL. 1977.
The bull shark, Carcharhinus leucas, from the
Upper Mississippi River near Alton, Illinois.
Copeia. 1977 (1): 166-168. DOI: https://doi.
org/10.2307/1443522 
THORSON TB. 1972. The status of the bull shark,
Carcharhinus leucas, in the Amazon River.
Copeia. 1972 (3): 601-605. DOI: https://doi.
org/10.2307/1442947
WERRY JM, LEE SY, LEMCKERT CJ, OTWAY NM.
2012. Natural or artificial? Habitat-use by the
bull shark, Carcharhinus leucas. PLoS ONE. 7
(11): e49796. DOI: https://doi.org/10.1371/
journal.pone.0049796