Survival, Growth, and Prey of Esocidae in

Experimental Systems

A. STEPHEN WEITHMAN AND RICHARD O. ANDERSON



Prey Vulnerability

Vulnerability to esocid predation was

highest for gizzard shad, goldfish, and

golden shiners, intermediate for bluegills

and largemouth bass, and lowest for channel

catfish. Variability in the results of six

prey-vulnerability trials was low; values

were averaged and presented as a percentage

of numbers eaten per number offered

for each prey species (Fig. 4). The largest

variation was in goldfish vulnerability; hybrids

consumed 35%, as compared with 58%

by northern pike and 62% by muskellunge

(Fig. 4). Electivity values (Ivlev 1961) were

positive for gizzard shad, goldfish, golden

shiners, and bluegills, near zero for

largemouth bass, and were negative for

channel catfish (Table 3).





Esocids in general, and

the hybrid in particular, should be able to

consume adult gizzard shad at a younger age

than other game fish.

Many studies have been conducted on the

food preference of esocids, especially

northern pike. Some investigators have reported

that esocids are piscivorous and feed

indiscriminately (Frost 1954; Crossman

1962); others have found that when given a

choice, northern pike prefer non-game over

game species (Beyerie and Williams 1%8;

Hunt 1965). We concur with the second

group--that when given a choice of prey

species, esocids feed selectively. In Pomme

de Terre Reservoir, muskellunge consumed

gizzard shad, carp (Cyprinus carpio), and

bluegills in that order (Vasey 1968). In confinement,

northern pike preferred gizzard

shad and carp over largemouth bass and

bluegills (Mauck and Coble 1971).