Feeding Habits of Walleye Larvae and Juveniles: Comparative Laboratory and Field Studies

Abstract

The feeding habits of larval and juvenile walleyes Stizostedion vitreum were examined in the field and laboratory. Walleyes are “strike” feeders and rely on vision to capture food. The mouth, jaws, and teeth are strongly developed by the time feeding begins about 5 days after hatching, but the gill rakers do not develop a filtering function until the juveniles are 20–30 mm long. The preferred food of postlarvae was crustacean zooplankton, about 1.2 mm in total length. Rotifers were not consumed at normal pond densities. Size selection of prey was more important than species selection. During the juvenile stage, walleye food preference shifted from zooplankton to larger, faster prey; first to Chaoborus sp. and mayflies, later to Gammarus lacuatris and fish. The rate of food consumption by juveniles varied with food preference; it was highest with Chaoborus sp. and fish, lower with Daphnia pulex, and lowest with Gammarus lacustris. The food consumption rate was linearly proportional to food density when Daphnia pulex was fed at densities less than 100 per liter. In highly turbid ponds, there were three periods of feeding activity per day, separated by 8‐hour intervals. The feeding periodicity of smaller walleyes was opposite to that of larger walleyes when both were present together in a pond. Predation on smaller fish (including cannibalism) was first observed when walleyes reached a total length of about 30 mm.

Selective feeding behavior of larval naked gobies Gobiosoma bosc and blennies Chasmodes bosquianus and Hypsoblennius hentzi:preferences for bivalve veligers

“…Wild plankton collections were combined to give total prey densities in each chamber of >l000 prey 1-' to ensure that food was not limiting (Connaughton 1994). These concentrations are similar to prey concentrations reported in other studies of larval fish feeding behavior (Mathias & Li 1982, Stoecker & Govoni 1984, Munk & Kierboe 1985, Mills et al 1987, Chesney 1989.…”

Competitive interactions between walleye (Sander vitreus) and smallmouth bass (Micropterus dolomieu) under various controlled conditions

“…Contrastingly, results from nighttime feeding experiments between juveniles of the two species showed no competitive advantage for WAE or SMB. WAE is known as a crepuscular feeder (Mathias and Li 1982) and has specialized sensory organs that may help confer an advantage over SMB when feeding at low light levels. Similar patterns have been observed for ruffe (which also has a specialized tapidum lucidum) and Eurasian perch (a visually oriented predator; Schlueter and Eckmann 2006).…”

Degree-day accumulation influences annual variability in growth of age-0 walleye

“…Walleye typically undergo a series of ontogenetic diet shifts in their first growing season, moving from zooplankton, to macroinvertebrates and finally to fish (Beck et al, 1998;Fox, 1989;Fox and Flowers, 1990;Fox et al, 1989;Johnston and Mathias, 1994a;Mathias and Li, 1982). The complexity of age-0 walleye food habits during the first growing season allows for many different scenarios in which food could be limiting (Colby and Nepszy, 1981).…”