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Migratory Restlessness and the Role of Androgen for Increasing Behavioral Drive in the Spawning Migration of the Japanese eel.

Sudo R, Tsukamoto K - Sci Rep (2015)

Bottom Line: This behavior is primarily known in birds, where it is considered to be an indicator of the urge for migration.To confirm migratory restlessness in a fish, we measured the locomotor activity of the Japanese eel, Anguilla japonica during its migration season.Silver eels had higher levels of the androgen hormone 11-ketotestosterone at the end of experiment than yellow eels.

View Article: PubMed Central - PubMed

Affiliation: Aquaculture Systems Division, National Research Institute of Aquaculture, Fisheries Research Agency, 422-1 Nakatsuhamaura Minami-Ise, Mie 516-0193, Japan.

ABSTRACT
Migratory restlessness refers to a type of locomotor activity observed just before the onset of a migration. This behavior is primarily known in birds, where it is considered to be an indicator of the urge for migration. In contrast, little is known about migratory restlessness in fishes. To confirm migratory restlessness in a fish, we measured the locomotor activity of the Japanese eel, Anguilla japonica during its migration season. Migratory-phase silver eels showed higher locomotor activity in aquaria than yellow eels at the non-migratiory growth-phase. Silver eels stayed outside of their shelters for longer durations in dark periods than yellow eels and were active even in light periods when yellow eels were inactive in the shelters. Silver eels had higher levels of the androgen hormone 11-ketotestosterone at the end of experiment than yellow eels. Administration of 11-ketotesosterone to yellow eels induced higher levels of locomotor activity than that observed in non-treated controls. These findings suggest that anguillid eels exhibit migratory restlessness just before their spawning migration and that 11-ketotestosterone may be involved in the onset of this behavior.

No MeSH data available.


Related in: MedlinePlus

Locomotor activity of Japanese eels.Activity (mean ± SE) was measured over72 h for (A) non-migrating (yellow) and migrating(silver) eels, and (B) 11-KT treated yellow eels and non-treatedcontrol yellow eels. Gray shading indicates dark-periods.
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f1: Locomotor activity of Japanese eels.Activity (mean ± SE) was measured over72 h for (A) non-migrating (yellow) and migrating(silver) eels, and (B) 11-KT treated yellow eels and non-treatedcontrol yellow eels. Gray shading indicates dark-periods.

Mentions: In both experiments, all eels exhibited generally higher levels of locomotor activityduring the dark periods than during the light periods (Fig.1). Yellow eels were most active in the early nighttime and showed almost noactivity during the day (Fig. 1A). Silver eels exhibitedhigher locomotor activity than yellow eels throughout the experimental period. Atthe end of the experiment, plasma 11-KT concentrations were significantly higher insilver eels than in yellow eels (U-test, p < 0.001)(Fig. 2). In the androgen administration experiment, 11-KTtreated eels showed high locomotor activity immediately after the lights wereswitched off. Their activity generally declined until the morning, when mostactivity had ceased. In contrast, non-treated control eels showed variable and muchlower activity during the night and very little activity during the day (Fig. 1B). Plasma 11-KT concentrations were significantly higherin 11-KT treated eels than in control eels whose 11-KT levels were similar to thatof yellow eels (U-test, p < 0.001).


Migratory Restlessness and the Role of Androgen for Increasing Behavioral Drive in the Spawning Migration of the Japanese eel.

Sudo R, Tsukamoto K - Sci Rep (2015)

Locomotor activity of Japanese eels.Activity (mean ± SE) was measured over72 h for (A) non-migrating (yellow) and migrating(silver) eels, and (B) 11-KT treated yellow eels and non-treatedcontrol yellow eels. Gray shading indicates dark-periods.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663494&req=5

f1: Locomotor activity of Japanese eels.Activity (mean ± SE) was measured over72 h for (A) non-migrating (yellow) and migrating(silver) eels, and (B) 11-KT treated yellow eels and non-treatedcontrol yellow eels. Gray shading indicates dark-periods.
Mentions: In both experiments, all eels exhibited generally higher levels of locomotor activityduring the dark periods than during the light periods (Fig.1). Yellow eels were most active in the early nighttime and showed almost noactivity during the day (Fig. 1A). Silver eels exhibitedhigher locomotor activity than yellow eels throughout the experimental period. Atthe end of the experiment, plasma 11-KT concentrations were significantly higher insilver eels than in yellow eels (U-test, p < 0.001)(Fig. 2). In the androgen administration experiment, 11-KTtreated eels showed high locomotor activity immediately after the lights wereswitched off. Their activity generally declined until the morning, when mostactivity had ceased. In contrast, non-treated control eels showed variable and muchlower activity during the night and very little activity during the day (Fig. 1B). Plasma 11-KT concentrations were significantly higherin 11-KT treated eels than in control eels whose 11-KT levels were similar to thatof yellow eels (U-test, p < 0.001).

Bottom Line: This behavior is primarily known in birds, where it is considered to be an indicator of the urge for migration.To confirm migratory restlessness in a fish, we measured the locomotor activity of the Japanese eel, Anguilla japonica during its migration season.Silver eels had higher levels of the androgen hormone 11-ketotestosterone at the end of experiment than yellow eels.

View Article: PubMed Central - PubMed

Affiliation: Aquaculture Systems Division, National Research Institute of Aquaculture, Fisheries Research Agency, 422-1 Nakatsuhamaura Minami-Ise, Mie 516-0193, Japan.

ABSTRACT
Migratory restlessness refers to a type of locomotor activity observed just before the onset of a migration. This behavior is primarily known in birds, where it is considered to be an indicator of the urge for migration. In contrast, little is known about migratory restlessness in fishes. To confirm migratory restlessness in a fish, we measured the locomotor activity of the Japanese eel, Anguilla japonica during its migration season. Migratory-phase silver eels showed higher locomotor activity in aquaria than yellow eels at the non-migratiory growth-phase. Silver eels stayed outside of their shelters for longer durations in dark periods than yellow eels and were active even in light periods when yellow eels were inactive in the shelters. Silver eels had higher levels of the androgen hormone 11-ketotestosterone at the end of experiment than yellow eels. Administration of 11-ketotesosterone to yellow eels induced higher levels of locomotor activity than that observed in non-treated controls. These findings suggest that anguillid eels exhibit migratory restlessness just before their spawning migration and that 11-ketotestosterone may be involved in the onset of this behavior.

No MeSH data available.


Related in: MedlinePlus