cintro.qxd 11/7/03 10:11 AM Page 1 • • • • Introduction his guide is derived from the widely praised and award-winning vol- ume Ken Schultz’s Fishing Encyclopedia. Weighing nearly 10 pounds T and containing 1,916 pages of information in an 8.5- by 11-inch for- mat, it is hardly a book that can be taken afield or casually perused. Among the many virtues of the encyclopedia is its detailed information about prey and predator species worldwide, which many people—including numerous lure designers, scientific researchers, and anglers—find very valu- able and which is available nowhere else. To make it easier for people inter- ested in the major North American fish species to reference this subject matter, that portion of the encyclopedia was excerpted into two compact and portable guides, Ken Schultz’s Field Guide to Freshwater Fish and Ken Schultz’s Field Guide to Saltwater Fish. These books are primarily intended for the angler, placing major empha- sis on gamefish species (nearly 260) sought in the fresh- and saltwaters of Canada, the United States, and Mexico, and on the prey species that most gamefish use for forage. Although many hundreds of species are included here, such compact books lack room for detailed information about many of the lesser species; however, they are well represented in the information that exists under certain groupings. For example, there are more than 300 species of “minnows” in North America, and much of what is said about them as a group in the freshwater guide pertains to the majority of individ- uals. Profiles are provided, nonetheless, of some of the more prominent members of this group. The same is true for some larger, more well-known groups of fish, like sharks. There are at least 370 species of sharks worldwide and dozens in North America. The saltwater guide provides an overview of this group, as well as specific information about the most prominent North American members. And, of course, color illustrations help identify the individual species profiled. There is a slight but deliberate content overlap in both books, as some species occur in both freshwater and saltwater. This is primarily true for anadromous fish like salmon, shad, and striped bass. However, a few salt- water species, such as snook, mullet, and ladyfish, are known to move into freshwater for part of their lives, even though they are not technically anadromous, and thus are also represented in both volumes. In this sense, 1 cintro.qxd 11/7/03 10:11 AM Page 2 certain species were included in both books for practical reasons, as opposed to purely scientific ones. At the end of the book is a glossary that explains the terms used in the species profiles, and following this introduction are two chapters of infor- mation invaluable to anyone who desires to know more about fish in a broad general sense. The Overview and the Fish Anatomy chapters are writ- ten in layman’s terms and provide concise information about fish that is use- ful to the angler, the naturalist, and even the aquarium hobbyist—all of whom share a passion and a concern for some of the most remarkable crea- tures on the planet. 2 Introduction cintro.qxd 11/7/03 10:11 AM Page 3 • • • • An Overview of Fish FISH The term “fish” is applied to a class of animals that includes some 21,000 extremely diverse species. Fish can be roughly defined (and there are a few exceptions) as cold-blooded creatures that have backbones, live in water, and have gills. The gills enable fish to “breathe” underwater, without draw- ing oxygen from the atmosphere. This is the primary difference between fish and all other vertebrates. Although such vertebrates as whales and turtles live in water, they cannot breathe underwater. No other vertebrate but the fish is able to live without breathing air. One family of fish, the lungfish, is able to breathe air when mature and actually loses its functional gills. Another family of fish, the tuna, is considered warm-blooded by many people, but the tuna is an exception. Fish are divided into four groups: the hagfish, the lampreys, cartilaginous fish, and bony fish. The hagfish and the lampreys lack jaws, and as such, they form the group called jawless fish; the cartilaginous fish and the bony fish have jaws. The bony fish are by far the most common, making up more than 95 percent of the world’s fish species. Cartilaginous fish, including sharks, rays, and skates, are the second largest group, numbering some 700 species. There are 32 species of hagfish and 40 species of lampreys. Overview Body of the fish. The body of a fish is particularly adapted to aquatic life. The body is equipped with fins for the purpose of locomotion. Scales and mucus protect the body and keep it streamlined. The skeleton features a long back- bone that can produce the side-to-side movements needed for forward propulsion in water. Since water is 800 times more dense than air, fish must be extremely strong to move in their environment. Fish respond to this con- dition by being mostly muscle. Thus, muscles make up 40 to 65 percent of a fish’s body weight. Many fish have air or gas bladders (sometimes called swim bladders), which allow them to float at their desired depth. Fish also have gills, their underwater breathing apparatus, located in the head. Most fish have only one gill cover, although some, like sharks, have gill slits, some as many as seven. The gills are the most fragile part of the fish; anglers should avoid touching the gills on fish that they plan on releasing. The limbs of fish come in the form of fins. A fin is a membrane that extends from the body of the fish and is supported by spines or rays. Because the number of rays is usually constant within a species, a ray count is often 3 cintro.qxd 11/7/03 10:11 AM Page 4 used by scientists to determine the species of a fish. Each of the fins on a fish has a name. Since these names are used in almost all descriptions of fish and are used in this book, it is worthwhile to become familiar with the different fin names. Moving from the head toward the tail, the first fins are the pectoral fins. The pectoral fins are used for balance and maneuvering in many species and in a few are used for propulsion. Further down the underside of the fish are the pelvic fins, located beneath the belly and used for balance. On the back of the fish is the dorsal fin. Some fish have more than one dorsal fin; in this case the dorsal fins are numbered, with the fin closest to the head called the first dorsal fin. Behind the dorsal fin on the top part of the fish there is occa- sionally a smaller, fleshy fin called the adipose fin. Back on the underside of the fish, behind the pelvic fins and the anus, is the anal fin. The final fin, usu- ally called the tail, is known scientifically as the caudal fin. The caudal fin is the most important fin for locomotion; by moving it from side to side, a fish is able to gather forward momentum. The scales of a fish form the main protection for the body. Fish scales are kept for the entire life of a fish; as a fish grows, the scales get larger, rather than growing anew. Scales are divided into several types. Most fish have ctenoid or cycloid scales. Ctenoid scales are serrated on one edge and feel rough when rubbed the wrong way (largemouth bass have such scales). Cycloid scales are entirely smooth, like the scales of trout. More rare types of fish have different types of scales: Sharks have more primitive placoid scales, which are spiny; sturgeon have ganoid scales, which form armor ridges along parts of the body. Some species, like catfish, have no scales at all. Fish scales can be used to determine the age of a fish. A fish scale will develop rings showing annual growth, much like the rings of a tree. Many fish also have a covering of mucus that gives them a slimy feel. This covering helps streamline their body and prevent infections. The mucus covering will rub off onto a person’s hands (this is the slimy substance that you can feel on your hands after handling a fish). Since the loss of mucus is detrimental to the fish, it is better to wet your hands before handling a fish that will be released to minimize the amount of mucus removed, being care- ful not to harm a fish by holding it too tightly. The skeletal and muscular systems of fish work together to maximize swimming power. The serially repeated vertebrae and the muscle structure work together to create the shimmering, undulating muscle movements that allow a fish to move forward quickly. This structure is particularly evident in a filleted fish, where the muscles show themselves in their interlocking pat- tern. The muscular nature of fish is the reason why fish make such good eat- ing and is also a factor in making fish a high-yield food source. Bony fish have developed an organ called an air bladder, which acts as a kind of flotation device. A fish’s body is naturally a bit more dense than water, but the air bladder, filled with gas, increases a fish’s ability to float. Fish can change the depth at which they float by varying the amount of gas in 4 An Overview of Fish cintro.qxd 11/7/03 10:11 AM Page 5 their air bladder.