Under public health guidelines to prevent the spread of the coronavirus, we are working remotely and are here to serve you virtually. Learn more about fish and fisheries in our publications section. For further information about fish and fisheries, contact Fisheries Outreach Specialist Titus Seilheimer. Usually independent of other fins troutperch-A; coho salmon-B , but attached to the caudal fin in the madtoms Noturus, Ictaluridae stonecat-C View Example. The anal fin may have spines and rays rock bass-A; brook stickleback-B or just rays common shiner-C; black bullhead-D View Example. The number of branchiostegal rays is useful for distinguishing certain species of Salmonidae and Esocidae rainbow trout-A; muskellunge-B View Example.
The number of spines or rays in the dorsal fin of a fish is a key morphological feature used to differentiate similar species. Dorsal fins may have only soft rays, as in the photo above, or a combination of spines and rays. Spines are bony, rigid and sometimes sharp projections that provide structure and can be used for defense. Fish are not always easy to distinguish by body shape alone, such as the three different minnow species Cyprinidae family in the photo below, so biologists rely on fin spine and ray counts, and fin shape and position to differentiate species. Holding a live fish still while counting small rays and spines can be a challenge. So, have you guessed which species are in these photos? It has more than 10 anal fin rays, while the other two fish in the lower photo have 8 or 9 anal fin rays.
Tail which the upper and lower lobes of tail fin are somewhat symmetrical and the vertebrae backbone flexes upward and partially extends onto tail fin. Found in gars. Intermediate between heterocercal and homocercal tails.
Fins are usually the most distinctive anatomical features of a fish. They are composed of bony spines or rays protruding from the body with skin covering them and joining them together, either in a webbed fashion, as seen in most bony fish , or similar to a flipper , as seen in sharks. Apart from the tail or caudal fin , fish fins have no direct connection with the spine and are supported only by muscles. Their principal function is to help the fish swim. Fins located in different places on the fish serve different purposes such as moving forward, turning, keeping an upright position or stopping.