Posthatching Histological Development of the Digestive System and Swim Bladder of Logperch, Percina caprodes

Abstract

The digestive system of the logperch, Percina caprodes, is partially formed at hatching and becomes functional before feeding begins. The swim bladder develops soon after yolk is depleted. Larvae have a straight gut, no stomach, a compact pancreas, a ventrally located gall bladder and a physostomous swim bladder. The larvae usually swim in midwater or near the surface. When larvae become juveniles, a stomach develops, the stomach and intestine develop the looped shape of adults, pancreatic tissue becomes disseminated, the gall bladder shifts to the right side and swimming consists of darting movements near the bottom. The transition from physostomous to physoclistous swim bladder occurs 1 to 2 months after the larvae become juveniles and does not correspond with the change in swimming behavior.