In this book, Peter Moyle successfully illustrates the joys of the study of living fishes, revealing why those of us who have spent a lifetime studying fish as a profession (ichthyology) consider ourselves to be so fortunate. We are constantly rewarded by discovering new and unexpected things that fish will do. Every visit to a stream or lake seems to add new insight into how fishes cope with their environment. These insights can be esoteric, such as discovering the sounds made by feeding pupfish in a crystalline Nevada spring. They can also be of considerable significance, such as discovering how...

The basic shape of a fish is simple; it can be drawn with a single sweep of a pencil. This elegant design is a reflection of how superbly adapted fish are to the “cool curving” world of water. To understand the ways of fish, the nature of their environment must be understood, as in many ways it is alien to us terrestrial creatures.

Because water is nearly eight hundred times more dense than air it is easy for fish to live suspended effortlessly in it, simply by balancing the heavy mass of bone and muscle with an internal float full...

It is said that when the great nineteenth-century biologist Louis Agassiz took on a new student, his first act was to lock the student in a room for a day, with only a dead fish for company. At the end of the day the student reported to the professor all he had learned about the fish from his examination of its features. Although this procedure is no longer standard practice at our universities, it is still true that you can learn a great deal about the biology of a fish simply by looking closely at its external anatomy. The external...

As this book was being readied to go to press, three colleagues of mine at the University of California, Davis, created a minor stir in the scientific world by filming with a video camera the inside of a fish’s mouth as it was feeding. Doctors Laurie Sanderson, Joseph Cech, and Mark Patterson inserted a tiny laser optic tube into the head of a Sacrament0 blackfish in order to discover how this fish manages to filter tiny particles from the water. Unfortunately, viewing the insides of a healthy, living fish is possible only with the aid of such extraordinary (and very...

Few things that fish do are as fascinating to people as the mass spawning runs of fishes such as alewife and salmon. In many areas people line the banks of coastal streams or crowd special viewing platforms to see spectacular events like those described by John Hay. We marvel at the internal urges that cause fish to enter the treacherous waters of a stream, often migrating hundreds of miles, blindly focused on reproduction. We wonder why so many of these magnificent fish have to die in order to reproduce. Like John Hay, we try to understand this behavior in terms...

Angel shark. Hagfish. Sarcastic fringehead. Warmouth. Whitefish. Grayling. Cardinal tetra. Wobbegong. Peacock flounder. Hogchoker. Zebrafish. The colorful names we give to fish reflect their enormous diversity. There are over 21,000 species of fish, with new species being described on a regular basis. They occur in an amazing array of habitats from high mountain streams to the depths of the ocean, with a diversity of adaptations to match their habitats. This chapter, and the ones that follow, can only give you a glimpse of this diversity, which is equal to that of all mammals, birds, reptiles, and amphibians combined.

We give...

I have spent a great deal of time under water, watching fish. The observations I make are carefully recorded on special forms and converted into data. The data are analyzed, summarized, and eventually turned into one of the arcane documents known as a scientific paper. The publications enable me to call myself a fish ecologist but they do not convey how enjoyable the underwater excursions are. They also do not allow me to record the myriad of other experiences I have had, such as watching how light and water together create lovely, shifting patterns on a lake or stream bottom,...

Coldwater streams are the epitome of flowing waters: clear, pure, and cold, falling and rippling down rocky mountainsides or smoothly meandering through flower-filled meadows. They are defined, in most people’s minds, by their ability to support trout and their close relatives, salmon, grayling, and whitefish. Yet a surprising number of such streams were without fish until trout were planted in them by eager anglers, especially in western North America. Even trout streams that already contained native trout now find themselves with one or more additional trout species. Brook trout from eastern North America have been planted in rainbow and cutthroat...

For many people, trout streams form the image of the ideal stream, but in reality there are many more miles of warmwater streams, which are often much more accessible to the average citizen. For the naturalist, small- to medium-sized warmwater streams present one of the most interesting aquatic habitats to study because they typically contain many species and individuals of fish (and other creatures). The stream closest to my own home in Davis, California, is Putah Creek, which has a surprisingly rich fish fauna, despite years of neglect and abuse. It is a natural attraction for local children who do...

I had the good fortune to grow up in a house situated on a ridge between two Minnesota lakes, one large, one small. The small lake was shallow and in winter minnows would swarm to holes chopped in the ice, desperately seeking the oxygen that had disappeared from the water. One of my earlier memories is falling into the chilly water when curiosity over the swarming fish overcame caution. My mother was amused to find fish in my pockets after I managed to make it home and change out of my soaked clothes. The large lake, Lake Minnetonka, was an...

Much of this book was written on a desk that overlooks a small pond in my backyard. I originally built the pond as a place to keep some of the increasingly rare native fishes that I study: Sacramento perch, Sacramento blackfish, California roach, and hitch. Thanks to neglect on my part and unauthorized additions to the fauna by family members, it now contains only a few blackfish but big schools of mosquitofish and goldfish. The pond nevertheless continues to be the center of life in my suburban back yard, full of scuds, insects, and algae as well as fish. It...

Since 1979, I have had a research project that samples fish on a monthly basis in a local estuary. The overwhelming impression of fish communities that such sampling gives is that of change: daily change with the height of the tide, seasonal change as fish move in and out in response to environmental change, and long-term change, as species become more or less abundant or as new species invade. The long-term change, unfortunately, is largely the result of human activity such as diversion of much of the inflowing fresh water for agriculture and invasions of new species, mostly carried in...

In June, 1963, a seaplane taxied up to a beach in Prince William Sound, Alaska, and let me off, so I could carry my gear a short distance to a research camp. I was a student assistant for a project that was studying an unusual phenomenon: the spawning of pink and chum salmon in a long reach of Olsen Creek that was periodically flooded by salt water. The flooding was the result of the astonishing tides of the region which rose and fell 3 to 4 meters in a day. The muddy tide flats around the creek, exposed at low...

Because I get seasick easily, I can understand why the oceans are still a frontier. There have been times that I have concluded that the only way to prove myself part of a rational species is to get off a heaving boat as quickly as possible. Nonetheless, a trawl full of brightly colored and oddly shaped fishusuallymakes an ocean expedition worthwhile. It is astonishing how little we know about most of the fish the trawl brings in or, for that matter, what goes on in the oceans in general, even on the shallow continental shelves that ring the...

For years I lectured on the fishes of tropical reefs in my classes, using colorful slides provided by colleagues, before I actually visited one. Even so, I was hardly prepared for the beauty and activity found on a tropical reef when I finally got a chance to snorkel over one. Photographs, no matter how good, simply could not prepare me for the sheer numbers of fish, seemingly in constant motion, with iridescent colors that changed constantly in the streaks of wave-dappled sunlight. After my initial astonishment wore off, I finally was able to focus on a coral knob, where a...

In 1989, two other scientists and I completed a report to the California Department of Fish and Game calledFish Species of Special Concern of California. We evaluated the status of the 113 native freshwater fishes in the state. We found that:

1. Seven were extinct.

2. Fourteen were officially listed as threatened or endangered.

3. Seven needed immediate listing as threatened or endangered.

4. Nineteen were in serious trouble and would merit listing soon if their populations continued to decline.

5. Twenty-five had declining populations or naturally limited ranges but did not appear to be in serious trouble, although their populations needed monitoring.

6....

The best tools that a naturalist has are an open mind, patience, and keen senses. Among the most pleasurable things a naturalist can do is to use these tools in a pleasing environment: a rushing stream, a pond, a tide pool, or a quiet bay. There is no question, however, that natural experiences can be enhanced by knowledge gained from previous studies and by the many tools modern technology provides at reasonable cost. The purpose of this chapter is to provide some access to the literature and other tools for the serious naturalist. I will first provide a short discussion...