Great White Sharks. The Biology of Carcharodon Carcharias

482 Pages·1998·30.022 MB·English

by  A. Peter Klimley and David G. Ainley (Eds.)

Contributors
Numbers in parentheses indicate the pages on which the authors' contribu Leonard J. V. Compagno (55, 91), Shark Research
tions begin. Center, South African Museum, Cape Town 8000,
South Africa
David G. Ainley (3, 223, 375), H. T. Harvey & Associ
Daniel E. Crocker (193), Department of Biology, and
ates, Alviso, California 95002
Institute for Marine Sciences, University of Califor
Jack A. Ames (309), California Department of Fish & nia, Santa Cruz, California 96064
Game, Monterey, California 93940
Leo S. Dempski (121), Division of Natural Sciences,
Scot D. Anderson (111, 175, 223, 241, 275, 281, 365,
New College, University of South Florida, Sara
375), Inverness, California 94937
sota, Florida 34243
Shelton P. Applegate (19), Instituto de Geologia, Uni-
Sheldon F. J. Dudley (351), Natal Sharks Board, Um-
versidad Nacional Autonoma de Mexico, Mexico
hlanga Rocks, South Africa
D.G. 04510, Mexico
Dave A. Ebert (91), US Abalone, Davenport, Cali
H. David Baldridge, Jr. (477), Sarasota, Florida 34239 fornia
Raymond Bandar (263), Department of Ornithology
Luis Espinosa-Arrubarrena (19), Instituto de Geolo
and Mammology, California Academy of Sciences,
gia, Universidad Nacional Autonoma de Mexico,
San Francisco, California 94118 Mexico D.G. 04510, Mexico
George W. Barlow (257), Department of Integrative
Ian K. Fergusson (321), European Shark Research Bu
Biology and Museum of Vertebrate Zoology, Uni reau, Herts AL7 2NN, Welwyn Garden City, En
versity of California, Berkeley, California 94720 gland
S. Curtis Bowman (55), Hughes-Bowman Design
Craig Ferreira (381), South African White Shark Re
Group, St. Augustine, Florida
search Institute, Capetown 8000, South Africa
Barry D. Bruce (401), CSIRO Division of Fisheries Re
Theo P. Ferreira (381), South African White Shark Re
search, Hobart, Tasmania 7001, Australia search Institute, Capetown 8000, South Africa
Elinor M. Bullen (393), Oceanographic Research In
Malcolm P. Francis (157), National Institute of Water
stitute, Durban 4000, South Africa and Atmospheric Research Ltd., Wellington, New
George H. Burgess (457), International Shark Attack Zealand
File, Florida Museum of Natural History, Univer
Otto B. F. Gadig (347), Departamento de Sistematica
sity of Florida, Gainesville, Florida 32611 e Ecologia, Campus Universitario, Universidad
Gregor M. Cailliet (81, 91, 415), Moss Landing Ma Federal de Paraiba, CCEN, Joao Pessoa, Paraiba,
rine Laboratory, Moss Landing, California 95039 Brazil
Matthew Callahan (457), International Shark Attack John J. Geibel (309), California Department of Fish
File, Florida Museum of Natural History, Univer and Game, Menlo Park, California 94025
sity of Florida, Gainesville, Florida 32611
Marci Glazer (481), Center for Marine Conservation,
Geremy Cliff (351, 393), Natal Sharks Board, Um- San Francisco, California 94104
hlanga Rocks, South Africa
Kenneth J. Goldman (111), Department of Biology,
Ralph S. Collier (217), Shark Research Committee, San Francisco State University, San Francisco, Cali
Van Nuys, California 91407 fornia 94132
tx
Contributors
Michael D. Gottfried (55), Calvert Marine Museum, R. Glenn Northcutt (121), Department of Neuro-
Solomons, Maryland 20688 sciences & Neurobiology, Unit of Scripps Institu
Anesh Govender (393), Oceanographic Research In tion of Oceanography, University of California, San
stitute, Durban 4000, South Africa Diego, La Jolla, California 92093
Krista D. Hanni (263), The Marine Mammal Center, Christine A. Pattison (309), California Department of
Sausalito, California 94965 Fish and Game, Morro Bay, California 93442
R. Philip Henderson (223, 275, 281), Point Reyes Bird Harold L. Pratt, Jr. (131), Narragansett Laboratory,
Observatory, Stinson Beach, California 94970 Narragansett, Rhode Island 02882
Burr Heneman (481), Living Resources, Bolinas, Cali Robert W. Purdy (67), Department of Paleobiology,
fornia 94924 National Museum of Natural History, Washington,
Gordon Hubbell (9), Jaws International, Key Bis- DC 20560
cayne, Florida 33149
Peter Pyle (175, 223, 241, 263, 275, 281, 375), Point
Robert E. Jones (263, 293), Museum of Vertebrate Zo Reyes Bird Observatory, Stinson Beach, California
ology, University of California, Berkeley, California 94970
94720
Jan Roletto (263), Gulf of the Farallones National Ma
Mark R. Jury (351), Oceanography Department, Uni rine Sanctuary, San Francisco, California 94123
versity of Cape Town, Rondebosch 7700, South Af
Ricardo S. Rosa (347), Departamento de Sistematica e
rica
Ecologia, Campus Universitario, Universidad Fed
A. Peter Klimley (3, 91, 111, 175, 241, 275, 281, 365),
eral de Paraiba, CCEN, Joao Pessoa, Paraiba, Brazil
Bodega Marine Laboratory, University of Califor
Wesley R. Strong Jr. (207, 229, 401, 471), Department
nia, Davis, Bodega Bay, California 94923
of Biology, University of California, Santa Barbara,
Robert N. Lea (419), Marine Resources Division, Cali
Santa Barbara, California 93106 and The Cousteau
fornia Department of Fish and Game, Monterey,
Society, Chesapeake, Virginia 23320
California 93940, and California Academy of Sci
ences, San Francisco, California 94118 Kazuyuki Teshima (139), Tohoku National Fisheries
Research Institute, Shinhama-cho, Shiogama, Mi-
Burney J. Le Boeuf (193), Department of Biology and
yagi, Japan
Institute for Marine Sciences, University of Califor
nia, Santa Cruz, California 96064 Antonio D. Testi (91), Italian Shark Research Project,
1-20148 Milano MI, Italy
Marie Levine (435), Shark Research Institute, Prince
ton, New Jersey 08540 Minora Toda (139), Okinawa Expo Aquarium, Mo-
Douglas J. Long (37, 263, 293, 317), Department of tobu-cho, Okinawa 905-03, Japan
Icthyology, California Academy of Sciences, Gold Senzo Uchida (139), Okinawa Expo Aquarium, Mo-
en Gate Park, San Francisco, California 94118 tobu-cho, Okinawa 905-03, Japan
Mark Marks (217), Shark Research Center, South Af
Rudy P. Van der Elst (393), Oceanographic Research
rican Museum, Capetown 8000, Republic of South
Institute, Durban 4000, South Africa
Africa
Benjamin M. Waggoner (37), Museum of Paleontol
Andrew P. Martin (49), Department of Biology, Uni
ogy, University of California, Berkeley, Berkeley,
versity of Nevada, Las Vegas, Las Vegas, Nevada
California 94720
89154
Ronald W. Warner (217), California Department of
John E. McCosker (111, 419), Steinhart Aquarium,
Fish and Game, Eureka, California 95501
California Academy of Sciences, Golden Gate Park,
San Francisco, California 94118 Frederich E. Wendell (309), California Department of
Fish and Game, Morro Bay, California 93442
Henry F. Mollet (81, 91), Monterey Bay Aquarium,
Monterey, California 93940 John West (449), Taronga Zoo, Masman NSW, 2088
Sidney, Australia
Richard C. Murphy (5, 401), The Cousteau Society,
Chesapeake, Virginia 23320 Trail K. Witthuhn (393), Struis Bay 7285, South Africa
Donald R. Nelson (401, 471), Department of Biolog Kazunari Yano (139), Seikai National Fisheries Re
ical Sciences, California State University, Long search Institute, Ishigaki Tropical Station, Fukai
Beach, California 90840 Ota, Ishigaki, Okinawa, Japan
Acknowledgments
Some of the chapters in this book originated from In order to keep the cost of this book as affordable
talks given at a symposium on the biology of the white as possible, we canvassed the scientific community
shark that was held at the Bodega Marine Laboratory for funds to help defray production expenses. The
of the University of California, Davis, on March 4-7, magnitude of the response to our plea was over
1993. For that reason, we acknowledge those persons whelming. The following organizations provided
who helped us organize that exciting meeting and the funds: Bodega Marine Laboratory, California Depart
organizations that provided the financial support for ment of Boating and Waterways, David and Lucille
it. Mr. Ed Ueber, Director, Gulf of the Farallones Na Packard Foundation, Gulf of the Farallones National
tional Marine Sanctuary, and Ms. Jan Roletto, Scien Marine Sanctuary, Monterey Bay National Marine
tific Coordinator, helped greatly in planning and ob Sanctuary, Natal Sharks Board of South Africa, Na
tained much of the financial support needed. Dr. James tional Audubon Society, Primary Industries South
Clegg, Director, Bodega Marine Laboratory, also worked Australia Fisheries, Point Reyes Bird Observatory, Sea
closely with us and made the university's facilities World of San Diego, Shark Research Institute of
available. Other organizations that contributed funds Princeton (New Jersey), the South Australian Research
include the following: Bodega Bay Sea Urchin Associa and Development Institute, and Discovery Channel.
tion, California Academy of Sciences, Cousteau Soci The insignias of these institutions are shown below.
ety, Marine Mammal Commission, National Audubon We thank the colleagues and institutions mentioned
Society, Sea World of San Diego, American Elasmo- above, and finally Pat and Susan for their patience
branch Society, and the U.S. Department of the Navy and support while we produced this volume.
(Office of Naval Research).
In bringing this book together, we are especially A, Peter Klimley
grateful to all the reviewers, to Ms. Diane Cosgrove, Bodega Bay, California
who converted all the tables into a consistent format, David G. Ainley
and to Academic Press for their assistance in plan Alviso, California
ning and publishing this important volume.
S A R D I
Monterey Bay /4
National Marine
Sanctuary LIVING
PS R() IUM rA HR Y AINUDSUTSRTARLIEIAS RDEESVEEALROCPHM EANNTD ^^^rS^!^* OCEANS
Nulional ^AudutMm Soticlv
Gulf of the mT^
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Farallones | ^"^
National Marine |'
Sanctuary SeaWorld.
ADVENTURE PARKS POINT REYES BIRD OBSERVATORY
Xt
C H A P T ER
1
White Shark Research in the Past:
A Perspective
A. PETER KLIMLEY DAVID G. AINLEY
Bodega Marine Laboratory H. T. Harvey & Associates
University of California, Davis Alviso, California
Bodega Bay, California
There are over 350 species of sharks, with mem to the interest and financial support of the U.S. Navy.
bers of the group as diverse as the huge plankton- However, it was only 10 years ago, on May 7, 1983,
feeding whale and basking sharks, tiny deep-water that a symposium was held at the California State
sharks that are bioluminescent or that take "cookie University, Fullerton campus on the biology of the
cutter" bites out of seals and whales, and the bizarre white shark. Although a few presentations at this
hammerhead sharks, with their greatly expanded meeting were quantitative, most sets of observations
rostrum. Yet humans often ignore this great diversity were small, and the other presentations consisted
and think of members of the group as conforming to a largely of anecdotal stories. Yet this meeting was a
single image, that of the white shark Carcharodon car- milestone. In any scientific discipline, we learn in a
charias. The public's fascination with this species is stepwise manner. Our first observations are anecdot
reflected by record attendance of the movie ]aws and al, only later to become increasingly quantitative as
its many sequels. The reason for this obsession is a we gather sufficient information to begin to ask test
morbid one. Humans consider the white shark dan able questions. Empirical studies then lead to experi
gerous—it feeds on us. One of us was possessed by mental ones. After that first meeting, relatively little
the strong emotional response aroused by this preda on the white shark appeared in the scientific litera
tor 10 years ago while witnessing a predatory attack ture until the symposium we organized at the Bodega
on a seal not more than 10 m from shore at Southeast Marine Laboratory of the University of California on
Farallon Island. The water was crimson red with March 4-7, 1993. This meeting drew scientists from
blood when the shark appeared, swimming back and six continents to talk on topics ranging from the evo
forth, high in the water. The experience sent a shiver lution of the white shark to its behavior.
down the spine and cold sweat to the forehead. Al A favorite topic of the press, newspaper articles
though all of us regularly experience the human feel about white sharks often contain ideas rather than
ings of thirst, hunger, anger, and sexual arousal, rare
facts, and this has frustrated those who are willing to
ly do we have the fear of being eaten. We feel this
obtain data in the slow, methodical manner charac
when watching a white shark devour a seal.
teristic of science. It takes great restraint not to say
Despite the human obsession with this predator, something that seems correct but which is based on
we have been slower to learn about the biology of this observations too few to make a firm conclusion. Dis
species. Since World War II, many studies have been seminating such ideas can lead to trouble later; only
conducted on the biology of sharks, primarily mem in the process of disproving ideas does science ad
bers of the family Carcharhinidae. This has been due vance closer to the truth.
GREAT WHITE SHARKS Copyright © 1996 by Academic Press, Inc.
The Biology of Carcharodon carcharias All rights of reproduction in any form reserved.
4 A. PETER KLIMLEY AND DAVID G. AINLEY
The public's misconception regarding this mythical idea was that the population of white sharks off the
species even occurs in the name of the shark, "white western coast of North America was growing because
shark." The first sharks that were seen were dead, seals and sea lions were steadily becoming more
lying on their back on the deck of a boat, and the abundant. In contrast, sharks were decreasing off the
species was given a popular name based on the color eastern coast as they became increasingly overfished.
ation of its belly. However, from an ecological per In fact, this was happening to white sharks there as
spective, "black shark" is probably a better name. well as elsewhere in the world. There was concern
This black coloration matches the color of a rocky or that this could occur on the West Coast. Another
vegetated bottom or the darkness over deep water. common speculation was that white sharks attack
Adult sharks can swim under their favorite prey, seals people because they look like seals swimming at the
and sea lions, without being detected and ambush surface of the water. This may seem obvious, but is
them from below. Even the other popular name, not a tested fact yet—much disagreement exists in
"maneater," is called to question in this book. In this book between the conclusions of Collier et al.
Chapter 22, Klimley et al. hypothesize that sharks (Chapter 19), Anderson et al. (Chapter 20), and Strong
often spit out humans, birds, and sea otters after seiz (Chapter 21). These and other controversial ideas
ing them, because their bodies lack the energy-rich were evaluated during the plenary sessions on popu
layers of fat possessed by pinnipeds and cetaceans. lation dynamics, predatory strategies, and attack
In organizing the symposium on the biology of the avoidance. Participants gave brief talks, a moderator
white shark, we first wanted to provide an oppor solicited questions from the audience, and a rappor
tunity for scientists to make traditional scientific pre teur gave a critical evaluation of the discussions pre
sentations. For this reason, we scheduled four ses sented. Three chapters in the book contain the com
sions on different aspects of the biology of the shark. ments of rapporteurs: Chapter 23 (by Barlow), Chapter
These resulted in papers that are now grouped to 38 (by Cailliet), and Chapter 44 (by Baldridge). Through
round out the eight sections of the book: Evolution, this process, we hoped to develop a consensus among
Anatomy, Physiology, Behavior, Ecology and Distri knowledgeable persons on these very controversial
bution, Population Biology, and Interactions with Hu topics.
mans. Academic Press has been very supportive, letting us
However, we also wanted to provide a forum for present all of this information to you in a single vol
evaluating several controversial ideas that had ap ume. We hope that you enjoy reading the many articles
peared repeatedly in newspapers and, for that rea as much as we did while preparing the volume.
son, are believed by the public to be facts. One such
C H A P T ER
2
A Plea for White Shark Conservation
RICHARD C. MURPHY
The Cousteau Society
Chesapeake, Virginia
When the Cousteaus began their expeditions in identification, and telemetry tracking, we found that
Australia, they did not plan to focus their attention some sharks regularly used a surprisingly small ex
on white sharks. However, after we arrived in South panse of ocean, remaining in or passing by the same
Australia and began investigating the situation, we localities over a period of months and even years. In
discovered that there were many questions not being all, we encountered 67 different white sharks. From
addressed. We had the good fortune to meet Mr. Bar tagging and resighting data, we estimated the popu
ry Bruce of the South Australian Department of Fish lation to consist of only a few hundred sharks in the
eries and offered to participate in their white shark entire study region. As no historical basis for compar
research program. Our involvement included the ison exists, we can only guess as to whether this
contribution of physical resources and some exper small population of sharks is depleted. What we do
tise, including that of Don Nelson and Rocky Strong. know, however, is that individuals of the species are
This work in South Australia resulted in the produc relatively rare and their rate of capture by humans is
tion of one television special, a coffee table book, and alarmingly high. During the first year of our project,
data which will be developed into a number of pa 3 of the 18 sharks we tagged were returned dead after
pers. I would like to offer some thoughts on great 78 days at liberty. Also, the male and female seg
whites based on our experiences with them. ments of the population appear to be segregated,
Throughout history, undeserved reputations of with the females frequenting areas that are generally
mythical proportions have beleaguered many fierce more accessible to fishermen.
animal species. Today, infamous acclaim continues to We are deeply concerned about the increasing
take a serious toll on the sharks, in particular, the monetary value of white shark jaws and teeth. This
white shark. Just how serious a toll, however, has creates a market for the capture of white sharks.
been difficult to determine. At the outset of our expe Shark populations will inevitably dwindle unless pru
dition in Australia, we asked the same question and dent controls are enacted. Fortunately, the govern
found only anecdotes for answers. Because we feared ments of both South Africa and Australia have al
that direct as well as incidental fishing pressure might ready taken up this cause on behalf of the white
be having a significant effect on the local population shark. Our reasons for wanting and needing to pro
of white sharks, we offered to investigate this possi tect this species are, in fact, the same as those applied
bility further and, toward this end, carried out five to the protection of other terrestrial top carnivores. In
expeditions between 1989 and 1991. addition to being increasingly rare, they are majestic
An important objective of our work was to tag as preeminent participants in a complicated food web
many white sharks as possible and to provide an op which we, as yet, only partially understand. Perhaps
portunity for a long-term assessment of population of greater concern is that our willingness and ability
dynamics. Using standardized baiting, mark and to properly manage white sharks and other creatures
GREAT WHITE SHARKS Copyright © 1996 by Academic Press, Inc.
The Biology of Carcharodon carcharias Ail rights of reproduction in any form reserved.
6 RICHARD C. MURPHY
are indicators of the economic, political, and sociolog- in approaching the difficult task of establishing a ratio-
ical health of our own species. We hope that future nal conservation and management program and pro-
management will establish strong safeguards against moting an appreciation for members of this unique
intentional and unintentional threats to the well-be- species, alive, in the wild, and performing their eco-
ing of the white shark. I am pleased to have joined logical functions,
the distinguished team of experts at the symposium
C H A P T ER
3
Using Tooth Structure to Determine
the Evolutionary History
of the White Shark
GORDON HUBBELL
Key Biscayne, Florida
Introduction bers of fossil white shark teeth of known geological
age. It is a dangerous practice to identify a fossil shark
Shark teeth are the most commonly collected verte species on the basis of examining one or two teeth. It
brate fossil. They appear on beaches, prairies, moun- is, however, very difficult to find large concentrations
taintops, and deserts, as well as in riverbeds. They of fossil white shark teeth in one stratigraphic hori
have also been found in the Antarctic and the deepest zon. There are numerous places that produce thou
part of the ocean. In the living shark, teeth are con sands of fossil teeth from the bull Carcharhinus leucas,
stantly produced and shed; a typical carcharhinid, N. brevirostris, and dusky shark Carcharhinus obscurus,
such as the lemon shark Negaprion brevirostris, may but few areas have appreciable numbers of white
produce 20,000 teeth in its first 25 years, and may live shark teeth. Relying on specimens collected by ama
as long as 50 years. Sharks have been very common teur or commercial collectors is problematic, as many
inhabitants of our oceans for about 400 million years, have little or no experience collecting data and exact
and shark teeth produce excellent fossils. Thus, it is geological ages are unknown. The compact shape
easy to understand why millions of fossilized shark and smooth enamel surface of fossil teeth offer little
teeth exist in marine deposits throughout the world. resistance to slippery hillsides or riverbanks, which
However, for the paleontologist trying to trace the allows them to settle into deposits from which they
evolution of white sharks using only fossilized did not originate; a rushing creek could displace them
teeth—which is a virtual necessity, as other portions far from their original site. Because of the number of
of shark bodies have not fossilized well—the task can teeth that a single shark can produce and shed in its
be very frustrating, because one cannot make accu lifetime, it is safe to assume that almost all of the teeth
rate deductions about the body length of the fossil that are collected are teeth that were shed when the
specimens, placement of the fins, or the relationship shark was still living. Since shark teeth do not devel
between the fins and other body structures. More op in sockets or are not fused to the jaw, as they are in
over, white shark teeth do not vary between the other vertebrates, there is nothing to hold them
sexes. Finally, disassociated fossil teeth in marine de in place when the animal dies. The teeth become scat
posits are difficult to assign to a geological age. tered and their association is quickly lost. The cartilagi
In order to completely understand tooth variability nous skeleton does not fossilize well and usually disin
and deformity, the scientist needs to study extant tegrates rapidly, eliminating any skeletal remains to tie
white shark jaws and tooth sets as well as large num the teeth to a particular geological formation. Natu-
GREAT WHITE SHARKS Copyright © 1996 by Academic Press, Inc.
The Biology of Carcharodon carcharias All rights of reproduction in any form reserved.
10 GORDON HUBBELL
rally associated sets of teeth, together with vertebrae able to salvage were the tooth sets. I also studied the
and other skeletal remains, are an extremely rare find first upper right tooth (A-2) from an additional 18
for tertiary sharks. Yet these naturally associated sets specimens.
represent the key to unlocking the mystery of the The upper teeth of a white shark show a notice
evolution of the white shark. able variation in size and shape according to their
In this chapter, I review the structure of white position in the jaw. I analyzed the characteristics of
shark teeth, as well as the variation therein and the the tooth crown (enamel) of the first five tooth posi
factors that cause them to vary, with the purpose of tions, starting from the front of the upper jaw in adult
establishing the basis on which white shark teeth can specimens (Table I). I refer here to tooth positions
be used to evaluate the fossil record of this species using the nomenclature proposed by Applegate and
and its ancestors (see also Chapter 4, by Applegate Espinosa-Arrubarrena (Chapter 4).
and Espinosa-Arrubarrena; Chapter 5, by Long and Six measurements were made of each tooth (Fig. 1).
Waggoner; and Chapter 8, by Purdy). Crown height: vertical distance between straight line
touching the lower extensions of the enamel adjacent
to the root at the base of the crown and a parallel line
Materials and Methods touching the tip of the enamel. Crown width: widest
part of the enamel at the base of the crown. Medial mar
I examined the jaws and tooth sets from 40 white gin: number of serrations along edge of the enamel
sharks ranging from 122 to 594 cm in total length (TL). toward the center of the mouth. Lateral margin: number
I purchased these from fishermen who had acciden of serrations along the edge of the enamel toward the
tally captured the sharks in their gill nets. In most side of the mouth. Degree of slant: The angle between a
cases, the fresh jaws were packed in salt and shipped line drawn perpendicular to a straight line touching
to me by air. They came from Western Australia (21), the lower extensions of the enamel and beginning at
southern California (11), Florida (4), South Australia the midpoint of the crown width and a line beginning
(2), the northeastern United States (1), and eastern at the same point and passing through the tip of the
Canada (1) and were collected between July 1980 and enamel. The angle was positive if the slant was to
February 1994, except for six specimens, for which ward the side of the mouth (i.e., lateral) and negative
the date of collection was not known. I removed the toward the center of the mouth (i.e., medial). All lin
muscle and loose connective tissue from the jaws ear measurements were normalized by dividing the
upon arrival. Then I bleached them in hydrogen per TL of the longest shark (594 cm) by that of each of the
oxide and dried them in an air-conditioned room after other sharks in order to derive an adjustment factor
they had been stretched out on a cloth-covered board. for each specimen. Each measurement was then mul
I received 11 jaws in such bad condition that all I was tiplied by the adjustment factor for the corresponding
+ Degrees
- Degrees of Slant
of Slant
Medial Lateral
Margin Margin
Midpoint
FIGURE 1 Measurements used for tooth description and comparison (viewed
from labial or outer surface).
3. Using Tooth Structure for .E volutionary History 11
TABLE I Crown Height and [ Angle for the First Five Upper Tooth Positions
Second anterior (A-2) Third anterior • (A-3) Intermediate (I) First lateral (L-1) Second lateral (L-2)
Tooth Specimen TL Ht N:Ht Angle Ht N:Ht Angle Ht N:Ht Angle Ht N:Ht Angle Ht N:Ht Angle
No. ID Sex (m) (mm) (mm)'' (deg)" (mm) (mm) (deg)" (mm) (mm) (deg)'' (mm) (mm) (deg) (mm) (mm) (deg)
1 T42392 M 3.79 32.5 50.9 1.0 31.5 49.4 4.0 21.5 33.7 -3.0 27.0 42.3 13.0 27.5 43.1 6.0
2 SP22294 F 3.91 32.5 49.4 2.0 33.0 50.1 3.0 23.0 34.9 -9.0 27.0 41.0 9.0 27.0 41.0 9.5
3 H93086 M 4.17 38.5 54.8 4.0 38.0 54.1 0.5 26.5 37.7 -9.0 31.0 44.2 16.0 34.0 48.4 9.0
4 F122793 M 4.27 35.0 48.7 4.5 34.0 47.3 2.0 25.0 34.8 -2.0 28.5 39.6 16.0 29.5 41.0 13.0
5 ADCJ U 4.27 36.0 50.1 2.5 35.5 49.4 3.0 24.0 33.4 -5.0 27.5 38.3 18.0 31.5 43.8 10.0
6 H32089 M 4.42 40.5 54.4 2.0 40.0 53.8 0.5 26.0 34.9 -8.5 29.5 39.6 10.0 34.0 45.7 7.5
7 H72589 U 4.57 37.0 48.1 3.0 37.0 48.1 1.0 27.5 35.7 -9.0 29.5 38.3 13.5 32.5 42.2 11.5
8 F9682 M 4.57 42.0 54.6 0 41.0 53.3 2.0 31.0 40.3 -9.0 34.5 44.8 16.0 37.0 48.1 10.0
9 F51089 F 4.57 35.0 45.5 -3.0 37.0 48.1 2.0 26.5 34.4 -8.0 31.5 40.9 12.5 33.5 43.5 6.5
10 SW41285 M 4.71 39.5 49.8 3.0 40.0 50.4 4.5 29.5 37.2 -14.5 35.5 44.8 14.0 37.5 47.3 8.0
11 G121382 M 4.72 38.5 48.5 7.0 38.5 48.5 0.0 28.0 35.2 -8.0 33.0 41.5 5.0 35.0 44.0 7.0
12 SP1394 M 4.74 43.5 54.5 5.0 43.0 53.9 3.0 34.0 42.6 -4.5 38.5 48.2 11.0
13 H8993 M 5.18 40.5 46.4 -3.5 38.0 43.6 7.5 30.0 34.4 -3.5 32.0 36.7 17.5 34.5 39.6 16.0
14 F22490 U 5.18 46.0 52.7 1.5 45.5 52.2 7.0 32.5 37.3 -8.0 37.0 42.4 11.0 39.5 45.3 13.0
15 F7687 F 5.18 48.5 55.6 1.0 47.5 54.5 4.0 33.5 38.4 -10.0 38.0 43.6 9.0 43.0 49.3 5.0
16 N11693 F 5.23 45.0 51.1 0 45.0 51.1 3.0 34.0 38.6 -11.0 38.0 43.2 17.0 41.5 47.1 8.0
17 R92185 F 5.36 47.5 52.6 3.5 46.0 51.0 1.5 29.5 32.7 -18.0 38.5 42.7 16.0 41.0 45.4 7.0
18 X11384B F 5.47 45.0 48.9 7.5 44.5 48.3 0 35.5 38.6 -5.0 38.0 41.3 13.0 39.5 42.9 13.0
19 H10991 F 5.54 43.0 46.1 0.5 42.0 45.0 3.5 29.0 31.1 -4.0 36.0 38.6 10.0 37.5 40.2 5.0
20 F82380 F 5.54 49.0 52.5 7.0 46.0 49.3 1.5 35.0 37.5 -7.0 41.5 44.5 13.0 43.5 46.6 9.0
21 L11685 F 5.63 48.0 50.6 4.0 45.5 48.0 4.5 31.5 33.2 -15.0 38.5 40.6 13.0 43.0 45.4 9.5
22 SW31287 U 5.64 52.0 54.8 0 51.5 54.2 2.5 33.5 35.3 -9.0 44.5 46.9 8.0
23 M91683 F 5.76 45.5 46.9 4.5 45.0 46.4 6.0 32.0 33.0 -5.0 37.0 38.2 10.0 42.5 43.8 8.5
24 H5384 F 5.94 49.0 49.0 3.0 48.5 48.5 0 32.5 32.5 -13.0 37.5 37.5 22.0 39.0 39.0 13.5
25 HI 12690 M 5.94 45.0 45.0 6.0 46.0 46.0 1.5 34.0 34.0 -7.0 37.5 37.5 20.0 38.5 38.5 13.5
26 F7282 F 5.94 44.5 44.5 4.0 44.5 44.5 -2.5 31.0 31.0 -6.5 36.5 36.5 16.0 36.0 36.0 12.0
N 26 26 26 24 26
Mean 50.2 49.6 35.5 40.8 43.9
SD 3.4 3.2 2.8 2.7 3.5
CV" 6.8 6.5 7.9 6.6 8.0
TL, Total length; Ht, height.
"Normalized N = measurement x (TL of largest specimen/TL of specimen with measurement); coefficient of variation (CV) = SD(100)/x. x refers to
deviation from perpendicular without regard for direction.
''Negative angles are in the medial direction; positive angles, in the lateral direction.
shark to produce measurements that would exist if all position slanted a few degrees medially (toward the
the shark specimens had been 594 cm long. front of the mouth) or laterally (toward the back of the
mouth). The slant angles averaged 2.7° for A-2 and
2.5° for A-3. The extremes were 7.5° lateral slant and
Results 3.5° medial slant. The tooth in the third position,
which is the intermediate tooth (I), differed greatly
Dimensions of the tooth crown are shown for 26 from the two anterior teeth. This tooth was shorter,
adult specimens ranging from 379 to 594 cm TL. The averaging only 35.5 mm in perpendicular crown
first two tooth positions (A-2 and A-3) in the upper height (normalized). It was always slanted medially
jaw were very similar, with mean crown heights of an average of 8.1° and showed the greatest recurva-
50.2 and 49.6 mm, respectively. The first position, ture of any of the tooth positions in 9 of the 26 jaws.
A-2, averaged slightly longer; however, in seven The fourth position represents the first lateral tooth
specimens, the crown height of A-3 was at least that (L-1); this tooth always slanted laterally an average of
of A-2. In both positions, the teeth were nearly per 13.8°. It was slightly longer (40.8 mm) than the inter
pendicular, but in some specimens, the teeth in either mediate tooth, but still was shorter than A-2. The