The Bottlenose Dolphin

638 Pages·1989·16.814 MB·English

by  Stephen Leatherwood and Randall R. Reeves (Eds.)

The Bottlenose Dolphin
Edited by
Stephen Leatherwood
Oceans Unlimited
San Diego, California, USA
Randall R. Reeves
Okapi Wildlife Associates
Hudson, Quebec, Canada
Academic Press, Inc.
Harcourt Brace Jovanovich, Publishers
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Copyright © 1990 by Academic Press, Inc.
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United Kingdom Edition published by
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Library of Congress Cataloging-in-Publication Data
The Bottlenose dolphin / edited by Stephen
Leatherwood and Randall R. Reeves
p. cm.
Includes index.
ISBN 0-12-440280-1 (alk. paper)
I. Atlantic bottlenose dolphin. I. Leatherwood, Stephen.
II. Reeves, Randall R.
QL737.C432B67 1989
599.5'3-dcl9 88-35093
CIP
Printed in the United States of America
90 91 92 93 9 8 7 6 5 4 3 2 1
This volume is dedicated to our friends and colleagues David K. Caldwell and
Melba C. Caldwell. By their hard work, integrity, and insight, the Caldwells
have inspired many of us in our studies of bottlenose dolphins and other
cetaceans.
V
Preface
Bottlenose dolphins, Tursiops truncatus, are among ery catches, strandings, and sightings surveys
the most familiar cetaceans. Because of their expo­ that bottlenose dolphins are present in virtu­
sure in captivity in marine parks and dolphinaria, ally all tropical and temperate marine waters. Lo­
movies, and television programs, as well as in the cal concentrations of bottlenose dolphins have
wild along tropical and warm temperate beaches provided, and will continue to provide, attractive
around the world, they are, to most schoolchildren opportunities for students seeking advanced
and landlubbers, the quintessential dolphins. They degrees. The increasing creativity shown in ap­
are also well known to field and laboratory scien­ proaches to basic population studies encourages
tists. Studies of wild bottlenose dolphins have newcomers to go beyond what once passed for
been encouraged by their relative accessibility. In discovery.
many lagoons, gulfs, and embayments and along Another reason for initiating this project was
discrete stretches of exposed outer coast, popula­ that we were aware of some good work that
tions of bottlenose dolphins can be observed and seemed to be taking too long to reach print. By
studied throughout much of the year. Since they providing an outlet for their contributions, we
are relatively easy to obtain and thrive in captivity, wanted to stimulate colleagues to write their re­
where they may survive at least as long as in the sults for formal presentation and scrutiny. Too
wild and reproduce successfully, bottlenose dol­ much interesting and useful information was lan­
phins have been used in a great variety of studies. guishing in files and contract reports, where access
Work with these dolphins in captivity has pro­ was limited to insiders only.
vided insight about sensory mechanisms, commu­ The first section, "Evolution and Fossil Record,"
nication systems, energetics, reproduction, ana­ consists of a single chapter. Lawrence G. Barnes
tomy, and many other aspects of cetacean biology outlines and evaluates the fossil record of bot­
generally. tlenose dolphins and offers several new interpreta­
This book is intended to serve several purposes. tions. The genus is represented by fossils dating to
First, we felt it would be useful to publish a series the early Pliocene epoch, about 4 million years ago.
of papers on the most widely studied genus in the Since the earliest fossils referable to Tursiops are
family Delphinidae, to demonstrate at once how from North America, the genus probably did not
much and how little is known about these animals. originate in the Mediterranean, as has been pos­
In that sense, we wanted the book to be a tulated. The bottlenose dolphin is a primitive
benchmark for researchers who, by seeing the vari­ member of the subfamily Delphininae, sharing
ety of topics and approaches presented under one some anatomical characters with the more primi­
cover, might get a better sense of how to direct tive stenine delphinids and the extinct Kentrio-
their own further work with this and other del- dontidae, the probable Miocene ancestors of the
phinid species. For example, many of us have be­ Delphinidae.
gun to ask how important or relevant additional In the second section, "Anatomy and Physiol­
area population inventories of bottlenose dolphins ogy," there are three chapters. Sentiel Rommel has
would be. To date, local or regional population used the excellent collection of skulls and skeletons
studies, using what have become standard in the United States National Museum to describe
procedures for identifying individuals with photo­ and illustrate the osteology of the bottlenose dol­
graphs, have been conducted in at least the United phin. Some skull and skeletal features have been
States, Mexico, Argentina, Australia, southern defined ambiguously in the literature. The author
Africa, and Portugal. We know from fish­ has developed more precise definitions and a stan-
xi
Xii PREFACE
dard terminology for the different parts of the dol­ quently increase their blubber mass during colder
phin skull and skeleton. periods.
Problems of identifying and describing muscle Sandra L. Hersh and Deborah A. Duffield report
groups in other mammals are compounded in ce­ that offshore bottlenose dolphins in the Northwest
taceans, whose body plans have been uniquely Atlantic have two electrophoretically distinguish­
modified for efficient aquatic locomotion. Also able hemoglobins, whereas coastal bottlenose dol­
using specimens in the United States National Mu­ phins from the same regions have only one hemo­
seum, D. Ann Pabst has brought some much- globin. The offshore dolphins are larger and have
needed order to this branch of cetology. In addition proportionately smaller flippers than the near-
to defining and illustrating the various muscle shore animals, and the two forms can be distin­
groups, she has, for the first time, treated the major guished further by certain skull features. The au­
connective tissues as discrete structures. Her com­ thors suggest that habitat may explain these
prehensive treatment of the bottlenose dolphin's biochemical and morphological differences. The
axial morphology is intended as a template for sim­ offshore ecotype lives in cool, deep water; the
ilar reviews of other cetaceans. Preliminary com­ coastal ecotype, in shallow, warm water.
parisons of bottlenose dolphins with other odonto- There are three chapters on "Life History and
cetes suggest that the general axial body plan is Biology" (Part IV). Very little is known about the
very conservative. biology of small odontocetes in the eastern South
As a veterinarian and scientist who has treated Pacific, despite the fact that large numbers have
and studied bottlenose dolphins for more than 25 been taken in fisheries off Peru and Chile. Koen
years, Sam H. Ridgway is well qualified to review Van Waerebeek and his colleagues began a pro­
what is known about their central nervous system. gram in the mid-1980s to document the distribu­
Besides critically summarizing the literature on tion, natural history, and exploitation of small
dolphin sensory systems and brain anatomy, he cetaceans in this region. They point out that bot­
offers comparisons with other mammalian groups, tlenose dolphins occur in coastal waters from at
including humans, and suggests ideas and ap­ least southern Ecuador to Concepcion, Chile, at
proaches for further research. 37°S. Preliminary evidence indicates the presence
Part III, "Systematics and Taxonomy," consists of two forms, coastal and offshore, differing in
of two chapters. First, Graham J. B. Ross and Victor cranial morphology, diet, and parasite fauna.
G. Cockcroft describe bottlenose dolphins in Aus­ Coastal animals also have significantly wider teeth
tralian waters by analyzing data mainly from mu­ than offshore animals. It is estimated that hun­
seum specimens and captive live animals, supple­ dreds of bottlenose dolphins, in addition to thou­
mented by new data from populations off southern sands of other dolphins, are killed annually by the
Africa. An important conclusion is that Ross's pre­ artisanal fisheries in central Peru.
vious recognition of Tursiops aduncus as a species Investigators in Florida have been collecting in­
separate from T. truncatus is retracted. T. aduncus is formation on stranded cetaceans systematically
a junior synonym of T. truncatus. The considerable since the mid-1970s. Using a sample of 170 beached
variability in such features as extent of ventral spot­ bottlenose dolphins collected from the Indian and
ting, body and skull length, and snout length and Banana River complex, January 1978 through De­
breadth nevertheless emphasizes the clinal differ­ cember 1983, Sandra L. Hersh and associates have
ences between bottlenose dolphin populations liv­ analyzed mortality patterns in the local dolphin
ing in different habitats, e.g., inshore versus off­ population. They estimate an annual mortality rate
shore, high versus low latitudes. The approach of about 7-9%. Mortality is seasonally uniform in
taken in this study may provide a useful model for most years, with noticeable increases only during
understanding the inshore-offshore differences in exceptionally cold winters. Newborn dolphins
bottlenose dolphin populations in other parts of have a somewhat higher mortality rate than other
the world. Feeding rates for a captive animal sug­ age classes. The authors emphasize that this kind
gest that bottlenose dolphins live in conditions of study can be done only in situations where car­
close to or below the lower limit of their thermo- cass salvage effort is intensive and consistent
neutral zone for most of the year, and conse­ throughout the year, and when information is
PREFACE Xiii
available on the size and age/sex composition of fine quantitatively, since their stereotypy involves
the living population. the contour configuration of loops (repetitive ele­
Many of us were stunned when in 1987 and 1988 ments) as well as more easily measured features.
approximately 750 bottlenose dolphins washed One function of signature whistles presumably is
ashore on the east coast of the United States, most to allow members of a social group to broadcast
having died from an insidious cause. This sad se­ their identity to their fellows. However, our appre­
ries of events was officially said to have been ciation of the social function of specific whistle con­
caused by poisoning from red-tide toxins in combi­ tours produced by particular individuals must
nation with bacterial and viral infections. Whatever await the development and application of tech­
its actual cause, the die-off brought clearly into niques for identifying which dolphin in an interact­
focus the need for reliable information on the basic ing group produces each whistle. The number of
biology, diseases, parasites, and feeding habits of loops in a given signature whistle can vary, de­
the bottlenose dolphins. pending on such factors as the behavioral context
Since the early 1970s, James G. Mead and and the dolphin's age.
Charles W. Potter of the United States National Detailed local studies have significantly ad­
Museum have been studying the biology of bot­ vanced our understanding of the behavior and
tlenose dolphins stranded between Massachusetts ecology of coastal bottlenose dolphins. Michael D.
and South Carolina. They report their basic find­ Scott and associates present a summary of the
ings from examination of 248 carcasses, most rep­ methods and findings of their long-term research
resenting the coastal form. The dolphins had fed program in Sarasota Bay on Florida's Gulf Coast,
mainly on three fish species (croakers, Micropogon uninterrupted since 1970. Although this chapter
undulatus, spot, Leiostomus xanthurus, and sea offers little that is new, we felt that the study's
trout, Cynoscion sp.) and were often infested with significance, both for the development of research
the trematode Braunina cordiformis. In this area, methods and for the insights obtained about bot­
bottlenose dolphins are born at a mean length of tlenose dolphin societies, merited the inclusiocn of
117 cm, reach an asymptotic length of 250 cm at an this brief review. The Sarasota program ha De-
age of 12 years, and become sexually mature at come the prototype for area population studies of
234 cm, 11 years, and a body weight of 150 kg bottlenose dolphins. Individual dolphins have
(females); or 160 cm, 11 years, and a single testis been followed over several generations, and
weight of about 100 g (males). Skull maturity was changes in behavior and association patterns have
found to be expressed at a mean age of 3.46 years in been documented as calves mature into adults. The
both sexes. study has illuminated pervasive differences be­
The largest section of the book, Part V, covers tween the reproductive strategies of male and fe­
topics within the broad subject areas of "Behavior male dolphins.
and Ecology." The study of dolphin sound produc­ Susan H. Shane worked in 1985 and 1986 in an
tion has been one of the most fruitful and provoca­ area off western Florida south of Sarasota. By in­
tive aspects of cetological research. Hearing is, stantaneous sampling of focal groups, she was able
without a doubt, these animals' most important to identify seven distinct types of feeding, each
sense. In addition to the well-known echolocation associated with specific ecological conditions.
clicks and burst pulsed sounds often described as Diurnal and seasonal activity patterns differed
squawks, yelps, or barks, bottlenose dolphins pro­ from those in other areas where bottlenose dol­
duce frequency-modulated, narrow-band sounds phins have been studied. Dolphin behavior was
called whistles. In 1965, David K. and Melba C. found to be affected by a complex web of interact­
Caldwell first noted that captive animals produce ing environmental features rather than by any one
individually distinctive, stereotyped whistles. In feature.
their chapter, the Caldwells, with co-author Peter Lisa T. Ballance studied a community of 155
Tyack, present and analyze a large sample of whis­ identifiable bottlenose dolphins in Kino Bay,
tle recordings made from 126 different dolphins to northeastern Gulf of California, Mexico, during
develop and test their signature-whistle hypothe­ 1984. She presents her findings concerning resi­
sis. Signature whistles have proven difficult to de­ dence patterns, group stability, and surfacing asso-
Xiv PREFACE
ciations. The dolphins exhibited different degrees dolphins feed mainly on bottom-dwelling fish; off­
of site fidelity and three different patterns of group shore dolphins, on cephalopods. Most fish species
membership. Individuals in some groups re­ consumed are known to be conspicuous sound
mained together over several months; some indi­ producers, and the authors suggest that bottlenose
viduals were seen only once in the presence of a dolphins use passive listening to detect prey.
group with frequently seen individuals; and some In many areas, bottlenose dolphins feed in asso­
individuals were often present but not consistently ciation with fishing operations. Peter J. Corkeron
associated with the same individuals. After con­ and colleagues took advantage of such an associa­
sidering differences and similarities between the tion in Moreton Bay, Australia, to evaluate food
dolphins in Kino Bay and those elsewhere, Bal- preferences. They noted how the dolphins follow­
lance speculates that the degree of site fidelity in ing a trawl net selected prey. At the completion of
this species may be highest in closed habitats, such trawls, they offered selected portions of the catch
as bays and lagoons, and lowest in open habitats, to nearby dolphins. The authors discovered that
such as exposed coasts. Synchrony in surfacing social factors which vary among groups affect the
patterns was short-lived and did not always in­ degree of choice available to any given individual,
volve long-term associates. thereby affecting the composition of its diet. Bene­
In the next chapter, Peter J. Corkeron compares fits of feeding around trawlers, e.g., easy access to
the behavior of bottlenose dolphins and Indo- food, are at least partly offset by increased risk of
Pacific humpbacked dolphins, Sousa chinensis, in capture in nets and increased threat of shark pre­
Moreton Bay, Australia, based on his observation dation.
of 334 and 50 photographically identified individu­ Unsolicited approaches to humans made by
als of the two species, respectively, over nearly wild dolphins are emotionally charged events, re­
three years. The two species occurred in mixed counted enthusiastically in mythology and factual
groups, found in association with trawlers and literatur e/./ Christina ,,Lockyer reviews the phenom­
dominated by bottlenose dolphins. Evidence sug­ enon of sociability in wild dolphins, treating in­
gests that the size of food patches created by trawl­ cidents by area, species, and type of interaction.
ing and possibly the threat of predation signifi­ We asked her to prepare this chapter because bot­
cantly affect the size of dolphin groups. tlenose dolphins do affiliate with humans in vari­
Three chapters offer new information on feed­ ous parts of their range, and this aspect of their
ing habits of bottlenose dolphins. From examina­ behavior has been widely publicized (and occa­
tion of stomachs of 127 dolphins which died after sionally exaggerated or distorted) in popular books
entangling in shark nets off southern Natal, South and articles. Lockyer's first-hand experience with
Africa, Victor G. Cockcroft and Graham J. B. Ross what she calls "sociable" wild bottlenose dolphins
document feeding on 72 species of fishes, elasmo- and her reputation as a scientist make her well
branchs, and cephalopods. They found some sea­ qualified to comment on what this extraordinary
sonal variation in proportions of the various spe­ behavior might mean.
cies, increases in prey length with predator length, With increasing scientific study of wild dol­
lower feeding rates in calves than in other animals, phins, progressively greater care is being taken to
and differences in feeding by age/sex class. The last replace subjective accounts with quantitative
finding is important in understanding home range descriptions of behavior. Richard C. Connor and
and social structure. Rachel A. Smolker provide a quantitative descrip­
Nelio B. Barros and Daniel K. Odell analyzed tion of a female dolphin's behavior toward her de­
the stomach contents of 76 bottlenose dolphins ceased calf.
stranded in the southeastern United States. They Resightings of recognizable individuals have
found otoliths from 43 fish species, including nine been at the core of many recent studies of bot­
prey taxa not previously reported for bottlenose tlenose dolphins. Among other things, they pro­
dolphins in this area, and cephalopod beaks repre­ vide insight into long-term site fidelity and
senting three families. Observed geographic varia­ changes in habitat use. In their chapter, Bernd
tion in diet appears consistent with regional differ­ Wiirsig and Graham Harris report that ten individ­
ences in relative availability of prey. Inshore ually identified dolphins in Golfo San Jose, Ar-
PREFACE XV
gentina, were associated with the same compan­ thousand) distinguishes pelagic from coastal bot­
ions in 1984 and 1986 as they had been in 1974 tlenose dolphins. There is also a tendency for dol­
through 1976. The natural marks permitting identi­ phins farther offshore to associate more frequently
fication had persisted for up to 12 years. However, with other cetaceans, although no more than 30%
the dolphins had shifted their pattern of move­ of the sightings involved such associations even in
ment away from the Gulf and occurred there only the areas farthest from shore.
sporadically from 1978 to 1986. Eight of the ten Based on analyses of sightings (1970-1983) and
recognizable animals were presumed to be fe­ data from photoidentification surveys (1981-1983),
males, judging by their proximity to calves born in Larry J. Hansen estimates that the southern Cali­
the previous summer or fall. fornia coastal population of bottlenose dolphins
Part VI, "Distribution, Movements, and Abun­ numbers about 240 animals. They normally range
dance," contains four chapters. Particularly in from Ensenada, Mexico, to Seal Beach, California,
view of the recent mass die-off of bottlenose dol­ but occur much farther north in some years. About
phins along the east coast of the United States 17% of identified animals exhibited some site fidel­
mentioned above, the extensive surveys of ity in San Diego County, where they seemed to
cetaceans on the continental shelf between Cape prefer a particular stretch of coast.
Hatteras, North Carolina, and the northern Gulf of Randall S. Wells and several co-authors report
Maine conducted between 1978 and 1983 by the sightings in the Monterey Bay area, central Califor­
University of Rhode Island have provided a valu­ nia, of bottlenose dolphins previously photoiden-
able baseline of information on dolphin popula­ tified only in southern California. They discuss
tions. Robert D. Kenney summarizes what was similar patterns of association in the two areas as
learned in this program about the bottlenose dol­ evidence of long-term social bonds and speculate
phin's distribution and population size. He esti­ on environmental causes of these long-distance
mates that in the early 1980s the population of
movements.
bottlenose dolphins off the northeastern United
Part VII contains four chapters on "Husbandry
States (Cape Hatteras north) numbered about
and Captive Breeding." The future of captive dol­
10,000-12,000. Only about 3-4% of this total is
phin programs may well depend on successful
considered to belong to the migratory nearshore
breeding. J. Pete Schroeder presents two chapters,
stock which was fished intensively during the
the second co-authored with Karl V. Keller, de­
1880s. As Kenney points out, either the nearshore
scribing the U.S. Navy's efforts to define reproduc­
stock is much smaller now than it was in the late
tive cycles of male and female bottlenose dolphins
nineteenth century, the current population has
and then to use that knowledge to enhance captive
been significantly underestimated, the surveys did
breeding programs by monitoring hormones, in­
not extend far enough south to census the majority
ducing ovulation, and artificially inseminating fe­
of dolphins in the coastal stock, and/or the nine­
males in estrus.
teenth century fishery also exploited the offshore
In the next chapter, Victor G. Cockcroft and
stock. The offshore stock, centered along the shelf
Graham J. B. Ross describe the physical and behav­
break, has a wider distribution and apparently tol­
ioral development of a bottlenose dolphin from its
erates a greater range of water temperatures than
birth in captivity to two years of age. The calf gen­
the inshore stock.
erally decreased his milk and energy intake with
Michael D. Scott and Susan J. Chivers have used age. He began taking solid food at an age of 321
the extensive data collected during tuna-fishing days but continued sucking facultatively until well
and research expeditions to the eastern tropical past his first year and probably beyond his second
Pacific to examine hypotheses about how and why year. He apparently received a progressively de­
bottlenose dolphin herd structure might vary in creasing energetic contribution from his mother's
coastal and pelagic habitats. Small groups (median milk. Energy intake increased substantially imme­
about 10 animals) are the norm in both kinds of diately after weaning.
habitat, and herd size does not increase with dis­ Successful maintenance of dolphins in captivity
tance offshore. The greater range of herd sizes depends on good health care programs. Edward D.
(from single individuals to aggregations of several Asper and colleagues present normal values and
XVi PREFACE
ranges for 31 hematology and serum chemistry nizable animals in Florida were seen no more than
clinical tests of blood from captive and wild bot­ 19 times each. Flexibility in adapting to different
tlenose dolphins. Age-related differences exist in regional conditions is cited as a principal factor in
some parameters, sex-related differences in others. the widespread distribution of bottlenose dolphins
However, in general, values for captive dolphins in coastal environments, including those with high
do not differ significantly from those for wild dol­ densities of human activity.
phins except insofar as the latter have a greater Harold W. Goforth, Jr. describes an experimen­
antigenic challenge and different diets and exercise tal method for studying various physiological and
regimes. metabolic responses to exercise by captive dol­
The next section (Part VIII) has seven chapters phins. A bottlenose dolphin was conditioned to
describing and evaluating recently developed "Re­ place its rostrum against a load cell (force trans­
search Techniques." Various kinds of tags, includ­ ducer), swim in place for 3-minute and 8-second
ing natural marks, freeze-brands, and radiotags, periods, and submit to blood sampling and muscle
have been useful in studies of dolphins. Michael D. biopsies. The 3-minute trials were used to measure
Scott and associates review the history of tagging tailbeat force during sustained swimming; the 8-
and marking studies, pointing out strengths and second trials, to measure maximum tailbeat force.
weaknesses of the various approaches. Daniel K. The dolphin's maximum thrust on a single tailbeat
Odell and Edward D. Asper provide details of their was 4730 newtons. Its maximum burst effort was
study in the Indian and Banana rivers, Florida, in 3263 newtons per tailbeat; its maximum sustained
which natural marks and freeze-brands were used swimming level, 1324 newtons per tailbeat. Maxi­
to study the distribution, movements, and dis­ mum burst speeds and sustained swimming
creteness of the dolphin population inhabiting this speeds of wild dolphins, about 21 and 15 knots,
sea-flushed lagoon network. The fact that methods respectively, are summarized and discussed. This
of tagging used required capturing and handling study demonstrates some of the scientific values of
dolphins, some more than once, permitted the au­ working with trained captive animals in controlled
thors to conduct biological sampling, and they re­ situations.
port some results of that sampling. Increasingly, layering patterns in teeth are being
Recognizing that the particular research meth­ used to estimate ages of dolphins. Such studies
ods employed may be as significant as actual be­ depend on knowing the rates at which layers
havior and population characteristics of the dol­ (called Growth Layer Groups, or GLGs) are de­
phins in affecting the outcome of a behavior study, posited and what factors influence those rates.
Susan H. Shane compares the approaches used in Aleta A. Hohn reviews the history of attempts to
and results from her own studies in Texas and define GLGs, summarizes her own work on
western Florida. The ad libitum sampling used in known-age, free-ranging bottlenose dolphins, and
Texas, and indeed in most studies of bottlenose points out some pitfalls of reading and interpreting
dolphin behavior, may be biased because it tends layers in teeth. She also offers counsel on how best
to overemphasize the more dramatic social behav­ to conduct studies and report findings so as to
ior while underemphasizing the less spectacular increase their usefulness to future investigators. In
behavior. The focal group sampling (following the next chapter, Albert C. Myrick, Jr., and Lanny
Altmann's classic 1974 paper) used in Florida more H. Cornell report the results of their age-estimation
accurately represents the full range of the animals' work with captive dolphins. They establish that
behavior. Even allowing for the differences in re­ one dentinal GLG is deposited per year in the teeth
search methods, however, the dolphins in Texas of bottlenose dolphins, and they identify principal
spent less time feeding than their counterparts in factors affecting the rate of dentine deposition.
Florida. The Texas dolphins used two of seven Deborah A. Duffield and Jan Chamberlin-Lea
identified feeding modes predominantly, while the report that each of 66 bottlenose dolphins they
Florida dolphins used each of the seven modes sampled had its own karyotypic signature. They
with approximately equal frequency. The fewer conclude that variability in R-banding of karyo­
recognizable animals in Texas were identified up to types and profiles of hemoglobins are useful in
156 times each, while the larger number of recog­ studies of populations and paternities.
PREFACE XVii
The final section, Part IX, consists of only one unforeseen, potentially devastating impacts of pol­
chapter on "Management." The live-capture fish­ lution and environmental degradation on dolphins
ery for bottlenose dolphins in the southeastern and their prey, the conventional approaches to
United States is managed by the National Marine management and conservation of bottlenose dol­
Fisheries Service under the Marine Mammal phins and other species will need to be re­
Protection Act of 1972. Gerald P. Scott describes evaluated in the coming years. We trust this book
the agency's goals and strategies. Annual quotas will give that process a boost.
of 2% or less of the estimated population are set; We are particularly grateful to two groups of
for regional management units, thought to cor­ colleagues for helping to create this book. First and
respond roughly with local stock boundaries. most obviously, the authors have done the re­
Readers should be advised that this chapter was search, analyses, and writing. We asked many of
current only through early 1987. The subsequent them to rethink, reanalyze, and rewrite portions of
die-off of dolphins in the eastern United States has their chapters after review, and we greatly appreci­
changed the atmosphere in which the manage­ ate the professional manner and positive spirit in
ment program operates. We expect the current pe­ which they have done so. The contributions by the
riod of re-evaluation, influenced by the sobering reviewers are less obvious but crucial to ensuring a
recognition that many animals in the coastal bot­ high standard of scholarship. We followed a peer
tlenose dolphin population north of central Florida review process similar to that used for scientific
died within a period of less than a year, to result in journals, sending all manuscripts to at least two
an even more conservative approach to manage­ anonymous reviewers. We, as editors, took into
ment of the live-capture fishery. account the reviewers' comments in deciding to
Inevitably, there are subjects which should have accept or reject a manuscript, and we sent these
been addressed in a book like this one but were and our own comments to authors with requests
not. We had initially hoped for somewhat broader for revision.
regional coverage. Although some areas not repre­ The reviewers were invariably generous and
sented in the book, such as coastal southern Africa, constructive in sharing their opinions, insights,
have been treated in previous publications, there and, in some instances, relevant new data. It is
are still large parts of the bottlenose dolphin's with sincere thanks that we list here (in alphabeti­
range for which little has been published. We had cal order) those who reviewed manuscripts sub­
hoped to include additional chapters directed at mitted for this book: Frank T. Awbrey, Lawrence
resolving the problems of Tursiops systematics. As G. Barnes, Kurt W. Benirschke, Peter B. Best, Mi­
noted by the Subcommittee on Small Cetaceans of chael A. Bigg, Daryl J. Boness, Jeffrey M. Breiwick,
the International Whaling Commission's Scientific Michael J. Bryden, Robert L. Brownell, Jr., John
Committee in 1974, there appear to be a number of Calambokidis, Christopher W. Clark, Victor G.
geographical races of this species, defined on the Cockcroft, Richard C. Connor, Lanny H. Cornell,
basis of body and tooth size as well as different James C. Cubbage, Randall W. Davis, Andrew E.
distributions relative to sea temperature and Dizon, Robert W. Eisner, John K. B. Ford, R. Ewan
depth. The names Tursiops aduncus, T. gillii, T. Fordyce, David E. Gaskin, Jonathan Gordon,
nuuanu, and T. gephyreus are still used in certain Nicholas Graham, Jack S. Grove, John D. Hall,
areas as though they represent valid species, so Philip S. Hammond, Larry J. Hansen, John Har-
their status begs to be clarified. We also would like wood, Sandra L. Hersh, Russ Hoelzel, Wayne
to have included more review chapters, covering Hoggard, Aleta Hohn, Jay Hyman, A. Blair Irvine,
such topics as echolocation, sensory systems, lan­ Ronald J. Jameson, Robert E. Jones, Brian E. Jo­
guage training, pathology and sensitivity to pollut­ seph, Steven K. Katona, Dennis Kelly, Margaret
ants, exploitation in fisheries and conservation
Klinowska, Scott D. Kraus, David M. Lavigne, Ri­
problems, habitat considerations, and world distri­
chard M. Laws, Alfredo A. Lichter, Christina Lock-
bution. Some of these are adequately covered else­
yer, Lloyd F. Lowry, Helene Marsh, William Med-
where, but others, such as the last four, are much
way, Albert C. Myrick, Jr., Mary K. Nerini, Daniel
needed.
K. Odell, Seiji Ohsumi, Thomas J. O'Shea, Jo­
In view of widening concern about the often sephine E. Pemberton, William F. Perrin, Wayne