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TOSHIAKI J. HARA
perceive taste substances. This clearly demonstrates distinct olfaction and
taste receptor functions in fish. Neurath (1949), using essentially similar
training technique, determined the threshold values for P-phenylethyl
alcohol (4.3 x
in the minnow Phorinus.
Similar threshold values for P-phenylethyl alcohol were also determined
for the minnow by Teichmann (1959). Teichmann also found that the
rainbow trout Salmo irideus detected P-phenylethyl alcohol at dilutions
of 1 x
this is nearly the same order of sensitivity as in humans.
Juvenile sockeye salmon ( Oncorhynchus nerka) detected eugenol at
concentrations higher than 1.8 x lo-? (Tarrant, 1966).
Hasler and Wisby (1950) used a conditioning technique for the biological assay of pollutants. Upon completion of the training period,
blinded bluntnose minnows, Hyborhynchus notutus, discriminated between phenol and p-chlorophenol at dilutions of less than 5 x le4. Similarly, coho salmon fry, Oncorhynchus kisutch, could easily detect
morpholine in concentrations as low as 1 X
Using a specially designed conditioning technique, Teichmann ( 1959 )
trained young European eels, Anguilla anguillu, to detect p-phenylethyl
alcohol, Z-menthol, citral, eugenol, and ionon; he established the thresholds for each. Calculations indicate that the limits for detecting a chemical range from dilutions of 3.5 x
( j?-phenylethyl alcohol) to 2 x
(ionon). The lowest threshold obtained in the eel is some 100 to
80 times lower than those of the minnow and rainbow trout. This can
be compared favorably with the olfactory sensitivity of a terrestrial macrosmatic animal such as the dog. Further, the threshold of the eel for Pphenylethyl alcohol showed seasonal fluctuations; it was lowest in late
winter and in midsummer, while about 60 times higher in late fall and in
early winter. Such a decrease in the olfactory sensitivity might be explained by central and hormonal regulation ( Teichmann, 1959).
Roaches, Leuciscus rutilus, were trained to induce a fright reaction
in response to benzol derivatives (Marcstrom, 1959). Thus fishes responded to benzol at dilutions of 2.0 x l W M and to phenol at 9.5 X
M . That these responses were olfactory was shown by the failure of
responses when the noses were destroyed. The thresholds of the fright
reaction to mononitrobenzol and lesolsine were five times higher than
those of intact fishes.
Recently, Miesner and von Baumgarten (1966) conducted an interesting study of olfactory perception and memory in the goldfish Carassius
auratus. Fishes were trained to recognize coumarin, and their swimming
movements were registered by means of specially designed technique.
Coumarin could be detected at dilutions of less than 1 X
Besides the
normal positive reaction to the stimulus, the fish exhibited several characand eugenol (6.0 x
(Hasler, 1957).
TOSHIAKI J. HARA
perceive taste substances. This clearly demonstrates distinct olfaction and
taste receptor functions in fish. Neurath (1949), using essentially similar
training technique, determined the threshold values for P-phenylethyl
alcohol (4.3 x
in the minnow Phorinus.
Similar threshold values for P-phenylethyl alcohol were also determined
for the minnow by Teichmann (1959). Teichmann also found that the
rainbow trout Salmo irideus detected P-phenylethyl alcohol at dilutions
of 1 x
this is nearly the same order of sensitivity as in humans.
Juvenile sockeye salmon ( Oncorhynchus nerka) detected eugenol at
concentrations higher than 1.8 x lo-? (Tarrant, 1966).
Hasler and Wisby (1950) used a conditioning technique for the biological assay of pollutants. Upon completion of the training period,
blinded bluntnose minnows, Hyborhynchus notutus, discriminated between phenol and p-chlorophenol at dilutions of less than 5 x le4. Similarly, coho salmon fry, Oncorhynchus kisutch, could easily detect
morpholine in concentrations as low as 1 X
Using a specially designed conditioning technique, Teichmann ( 1959 )
trained young European eels, Anguilla anguillu, to detect p-phenylethyl
alcohol, Z-menthol, citral, eugenol, and ionon; he established the thresholds for each. Calculations indicate that the limits for detecting a chemical range from dilutions of 3.5 x
( j?-phenylethyl alcohol) to 2 x
(ionon). The lowest threshold obtained in the eel is some 100 to
80 times lower than those of the minnow and rainbow trout. This can
be compared favorably with the olfactory sensitivity of a terrestrial macrosmatic animal such as the dog. Further, the threshold of the eel for Pphenylethyl alcohol showed seasonal fluctuations; it was lowest in late
winter and in midsummer, while about 60 times higher in late fall and in
early winter. Such a decrease in the olfactory sensitivity might be explained by central and hormonal regulation ( Teichmann, 1959).
Roaches, Leuciscus rutilus, were trained to induce a fright reaction
in response to benzol derivatives (Marcstrom, 1959). Thus fishes responded to benzol at dilutions of 2.0 x l W M and to phenol at 9.5 X
M . That these responses were olfactory was shown by the failure of
responses when the noses were destroyed. The thresholds of the fright
reaction to mononitrobenzol and lesolsine were five times higher than
those of intact fishes.
Recently, Miesner and von Baumgarten (1966) conducted an interesting study of olfactory perception and memory in the goldfish Carassius
auratus. Fishes were trained to recognize coumarin, and their swimming
movements were registered by means of specially designed technique.
Coumarin could be detected at dilutions of less than 1 X
Besides the
normal positive reaction to the stimulus, the fish exhibited several characand eugenol (6.0 x
(Hasler, 1957).