|You’ve caught an unfamiliar fish. What is it? You can look at a picture or drawing, ask someone who you think is knowledgeable, or you can consult a fish identification guide or field guide. Taxonomy is what science calls classifying living things according to their similar and dissimilar physical characteristics, and putting them in like-appearing groups.
Using a key, and without any previous knowledge or even a good guess, you can look at a fish, note physical items like the shape of its tail, the pattern of its scales, and whether it has a lateral line. You progress from point to point, clue to clue, as a detective, to “key out” what fish you wish to identify. A fish can be scientifically keyed out by counting fin rays and scales in certain positions, looking at the arrangement of pharyngeal teeth, and so on. For most people, the use of field marks, easily visible external features, is enough. Some fish of the same family may look nearly alike. Their color patterns fade as they grow older or when they are found in certain water conditions. Thus, field marks, like the number of pores under the jaw, can help you tell the difference between a muskellunge and a northern pike.
Beginning with 1a and 1b below, match the information to the characteristics of the fish you wish to identify. When you have placed the fish in its proper family, click on the link to the family for help in determining the specific species. As you progress through the key, refer to the illustrations in Chapter 1 and the glossary.