An Apparatus for Estimating the
Effects of Toxicants on the Critical Flicker
Frequency Response of the Bluegill Sunfish
ARTHUR SCHEIER, Director
Bio-Assay Laboratories
Academy of Natural Sciences
Philadelphia, Pennsylvania
JOHN CAIRNS, JR., Professor
Zoology Department
University of Kansas
Lawrence, Kansas
INTRODUCTION
Investigators have for many years measured the effects of toxic substances
upon fish by using death as the indicator. The crudeness of such a measure is
self-evident. In recent years, measurements of subtle changes in physiological
functionhave been attempted and assessment is often possible before those changes
become irreversible. Weiss (l)has been able to measure the depression of acetylcholinesterase activity in fish brain tissue as it is related to the concentration of
an inhibiting compound, the compound's specific nature, and the length of exposure time. He found that when fish were returned to uncontaminated water,
restoration of acetylcholinesterase activity occurred. Cairns and Scheier (2,3)
have studied the effects upon fish oxygen consumption, fatigue factors, and gill
structure resulting from exposure to toxic materials. Mount and Stephan (4) proposed a "laboratory fish production index" which reflects effects upon growth,
reproduction, spawning behavior, viability of eggs, and growth of fry, as the
measure of detrimental effect upon an environment.
The apparatus and experiments described in this paper are a further attempt
to measure subtle changes in physiological function as it relates to the fish's ability to respond to light flicker stimulus. The effect of light stimulus to fishes has
been a subject of investigation for some time. Gmndfest (5), while investigating
the function of visual purple, also measured the amount of "spectral energy"
which produced a visual orienting response to the displacement of a constant
background in the sunfish. Gmndfest (6) measured the visual orienting response to
a movement pattern of fine lines. Rowley (7) found that goldfish could distinguish differences between stripes of from two to eight mm in width, and concluded that goldfish have a high degree of visual acuity. Wolf and Zerrahn-Wolf
(8) found that the sunfish responds to a moving system of stripes by a motion of its
body. They further stated that the fish could distinguish flicker at illuminations
lower than those distinguishable by the human eye. Hanyu and Ali (9) measured
the light intensity-fusion frequency relationship in the goldfish, and found that
maximum fusion frequency increases with temperature -- contrary to the findings
of Crozier, et al (10). Crozier, working with sunfish, found no difference in
flicker fusion frequency response at three different temperatures. Davis (11)
studied light-shock reaction in the bluegill, and charted a sequence of peculiar
movements and postures resulting from light-dark shock stimulus. Shaw and
Tucker (12) charted the optomotor reaction of schooling carangid fishes. They
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