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SHARKS OF THE SHALLOWS Coastal Species in Florida and the Bahamas

JEFFREY C. CARRIER photographs by Andy Murch, Jillian Morris, and Duncan Brake

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gile, sleek, and precise, sharks display many qualities we can admire and appreciate. These marvels of evolution have adapted to thrive in every major aquatic realm on the planet, from frigid Arctic waters through temperate but stormy seas and on into the tropics. However, few places on Earth are home to the amazing diversity of shark species that beautify the shallow waters of Florida and the Bahamas. In this first-ever book dedicated to the sharks of this region, biologist Jeffrey C. Carrier reveals the captivating lives of these large marine predators and describes how they have survived for over 400 million years. Guiding readers through basic biology, key attributes, and identification tips, the book explores what makes sharks such successful apex predators. Carrier

explains fascinating phenomena, including the reason for the bizarre shape of the hammerhead, how a bull shark is able to swim hundreds of miles up freshwater rivers, what lies behind sharks’ remarkable capability to learn and remember, and why many scientists believe that they are equipped with the most sophisticated sensory systems in the animal kingdom. With the stunning full-color underwater photography of Andy Murch, Jillian Morris, and Duncan Brake, Sharks of the Shallows brings boaters, fishers, divers, and shark lovers directly alongside these unfairly maligned creatures. And not a moment too soon! Sharks are experiencing stresses unlike any in their long history, and are struggling to survive in a changing ocean. They will continue to grace our coastlines only if we care enough to understand them.

Jeffrey C. Carrier is professor emeritus of biology at Albion College and an adjunct research scientist with Mote Marine Laboratory. He is the senior coeditor of Biology of Sharks

and Their Relatives and Sharks and Their Relatives II: Biodiversity, Adaptive Physiology, and Conservation. Andy Murch, the founder of Big Fish Expeditions, is a shark conservationist and photographer. Jillian Morris, the founder of Sharks4Kids, is a shark conservationist, photographer, and videographer. Duncan Brake, the founder of Oceanicallstars, is a photographer and Emmy-nominated cinematographer.


Contents

CONTENTS Preface   vii Acknowledgments   xi

Thrilling underwater photographs enrich this unique guide to the shallow-water sharks of Florida and the Bahamas.

PART ONE. INTRODUCTION TO SHARKS AND THEIR RELATIVES    1 PART TWO. SELECTED SHARK SPECIES    43

Atlantic Sharpnose Shark   45

Lemon Shark   91

Basking Shark   48

Mako Shark   96

Blacknose Shark   52

Nurse Shark   100

Blacktip Shark   55

Oceanic Whitetip Shark   107

Bonnethead Shark   60

Sandbar Shark   111

Bull Shark   63

Sandtiger Shark   115

Caribbean Reef Shark   67

Silky Shark   120

Dusky Shark   72

Smoothhound Sharks   123

Finetooth Shark   75

Spinner Shark   126

Great White Shark   77

Tiger Shark   129

Hammerhead Sharks   83

Whale Shark   134

PART THREE. SKATES AND RAYS, INCLUDING SAWFISH

Atlantic Stingray and Southern Stingray   141

Roughtail Stingray   157

Clearnose Skate   146

Spotted Eagle Ray   163

Cownose Ray   150

Yellow Stingray   166

Sawfish   160

Mantas and Mobulid Rays   153 Appendix: Sharks, Skates, and Rays of the World   169 References   171 Index   189

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S HA r kS o f t He S H A llo w S

Conservation and Management Fishing Regulations

Because of their vulnerability to overfishing, many shark species are protected and may not be taken by recreational boaters, fishers, Cage diving to view and photograph white sharks has become increasingly popular with a better understanding of where and when the animals can be dependably found.

Entire industries have developed to support the public’s interest in diving with white sharks. Being in the water with a 16-foot white shark satisfies even the most steadfast adrenalin junkie’s quest for adventure.

or divers. Some of these species are protected from commercial fishing as well. Many other species are not under threat and may be taken, subject to size restrictions and bag limits. Because some of these species are actually endangered or threatened, special care must


I n tr o Du C tI o n t o S H A rk S An D t H eI r relAt I v eS

be taken to properly identify every animal, to be certain of its identity and protected status. Fines are large and jail terms are possible for mistakes in identification. The management of these species is under constant review. As a result, the regulations may change frequently, so fishers must consult the latest state and federal rules to stay current with regulatory changes. In the Bahamas, the regulations are easy to understand: they ban all fishing for sharks. If sharks are caught by accident, they must be immediately released. In Florida, deciphering the rules and regulations is more complicated, because different regulations may apply to state waters, Atlantic waters, and the Gulf of Mexico. Trying to make sense of the various regulations and where they overlap can be a challenge. The federal government’s advice “If you don’t know, let it go” is probably a good rule of thumb to avoid issues

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of identification if one is stopped by an enforcement officer. Regulations are constantly changing as new data emerge, so fishers are advised to make certain they are complying with the most recent regulations. Federal rules prohibit retention of the following eight Florida species, all of which are described in this book: • • • • • • • •

Basking shark Caribbean reef shark Dusky shark Great white shark Sandbar shark Sandtiger shark Silky shark Whale shark

Florida laws prohibit retention of all of those species as well as the following five species:

Diving with sharks is only one way people can experience a shark encounter. Fishing for sharks is still popular, though it is highly regulated in most areas. Shark fishing is banned in the Bahamas, and many species are closely protected in Florida waters. For most of the species not prohibited, there are size limits and possession limits.


Whale Shark

Common Name: whale shark Scientific Name: Rhincodon typus Identifying Features: Whale sharks are very

As the largest fish in the sea, the whale shark dwarfs this diver, who is attempting to fit the entire length of the shark into a single photograph. Whale sharks are known to exceed 40 feet (12 m) in length.

large and have a blunt, flattened head. They are gray to brownish in color with yellow or whitish spots. A whale shark’s mouth is located at the front of the snout, and there are very prominent ridges running along the sides. Its size, as the largest shark species, and its white-spotted skin make it easy to identify. In fact, the pattern of spots is different for each individual shark. Identification is often made by photographing the animal and comparing its pattern to a database of known animals. This tool is especially

important as an aid to identify whale sharks that return to the same location periodically. If they can be dependably identified, elements of their life history patterns can be more easily determined. Frequency: rare

“You’re gonna need a bigger boat.” These words from the movie Jaws were spoken in reference to a great white shark. But they are even more appropriate to describe whale sharks, which hold the distinction of the largest fish in the sea. The impact on moviegoers, however, would not seem as startling if the hunters were seeking a large planktonfeeding shark rather than a supposed rogue, man-eating species.

range, Distribution, and Habitat Preference Whale sharks are found worldwide, preferring tropical and near-tropical waters, where water temperatures are reliably above 70°F (21°C). Large aggregations have been found in the Philippines and around Mexico, South Africa, and Australia. They are not very abundant in Florida and Bahamian waters. When they are sighted, it is generally offshore in deeper water, though some have been seen inside the reefs in the Florida Keys and some have been discovered beached in these same


w H A le S H A rk

islands. Reports of whale sharks around Andros Island and the Exumas in the Bahamas indicate that they will venture into shallow waters on occasion. Fishers who prefer to troll for large game fish at longer distance offshore are more likely to spot them than are beachgoers or divers.

Size, Age, growth, and reproduction Lengths in excess of 40 feet (12.2 meters) have been measured, though there are reports of larger animals. Exact measurements of animals reported to be larger are absent, and these are generally regarded as estimates. Most studies of growth rely on measurements taken during initial tagging and later recapture and remeasurement. The difficulty of obtaining an accurate length for such a large animal makes estimates of growth very difficult, if not impossible. The few estimates of growth that exist come from a few captive

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studies and show an annual growth of 8 to 11 inches (21.6–29.5 cm) per year. Mathematical models predict that whale sharks could live anywhere from 60 to 100 years, though these life spans have not been validated. Computerized scans of the patterns of spots on whale sharks indicate that individual sharks can be recognized from their unique pattern. The eventual creation of a worldwide database indexing the spot pattern for every whale shark encountered may make tracking and life history studies more revealing. Other advances in technology may make underwater measurements of total length possible. The combination of these techniques may ultimately allow for the determination of accurate growth rates from these data. Better insights into life history, gained from wild populations rather than captive sharks, may then become possible. What sparse information is available re-

The unusual perspective of a wide-angle lens distorts the true size and exaggerates the proportions of this filter-feeding giant, but it does shows the mammoth volume of water that can be filtered of its plankton by a feeding whale shark.


SHARKS OF THE SHALLOWS Coastal Species in Florida and the Bahamas

JEFFREY C. CARRIER photographs by Andy Murch, Jillian Morris, and Duncan Brake

Sales queries: Kerry Cahill Sales Director 410-516-6936 KPC@press.jhu.edu Media queries: Kathryn Marguy Publicist 410-516-6930 KRM@press.jhu.edu

Publication date August 2017  216 pages 8 ½ x 11   239 color plates 978-1-4214-2294-7 $34.95 £26.00 hc Also available as an e-book

press.jhu.edu

Sharks of the Shallows  

Thrilling underwater photographs enrich this unique guide to the shallow-water sharks of Florida and the Bahamas from Johns Hopkins Universi...

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