The daily activity patterns of Euastacus sulcatus (Decapoda: Parastacidae) in southeast Queensland
Author(s)
Furse, James
Wild, Clyde
Sirotti, Simon
Pethybridge, Heidi
Year published
2006
Metadata
Show full item recordAbstract
Freshwater crayfish are regarded as principally nocturnal, however Euastacus sulcatus is commonly observed during daylight hours, both in-stream, and wandering overland, suggesting that this species is diurnal. During the winter-summer of 2002/2003 we investigated the activity patterns of E. sulcatus using a series of continuous 24 hour observation sessions. The results of this study indicate that this species is active in all seasons, except for large crayfish (>40 mm OCL), which are rarely observed in spring and winter, but are common in summer. We conclude that E. sulcatus is a diurnal species, and that peak activity ...
View more >Freshwater crayfish are regarded as principally nocturnal, however Euastacus sulcatus is commonly observed during daylight hours, both in-stream, and wandering overland, suggesting that this species is diurnal. During the winter-summer of 2002/2003 we investigated the activity patterns of E. sulcatus using a series of continuous 24 hour observation sessions. The results of this study indicate that this species is active in all seasons, except for large crayfish (>40 mm OCL), which are rarely observed in spring and winter, but are common in summer. We conclude that E. sulcatus is a diurnal species, and that peak activity generally occurs around midday in all seasons, except in the case of small crayfish (<25 mm OCL), which become nocturnal in summer when the time of their peak activity changes from around midday, to around midnight. We suggest that this general pattern of diurnal activity may be a predator-avoidance strategy, as many carnivorous Australian mammals are nocturnal. The nocturnal activity patterns seen in small crayfish during summer may also be a predator-avoidance strategy, but the diurnal predators in this case could be the large crayfish, which are active only in the summer.
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View more >Freshwater crayfish are regarded as principally nocturnal, however Euastacus sulcatus is commonly observed during daylight hours, both in-stream, and wandering overland, suggesting that this species is diurnal. During the winter-summer of 2002/2003 we investigated the activity patterns of E. sulcatus using a series of continuous 24 hour observation sessions. The results of this study indicate that this species is active in all seasons, except for large crayfish (>40 mm OCL), which are rarely observed in spring and winter, but are common in summer. We conclude that E. sulcatus is a diurnal species, and that peak activity generally occurs around midday in all seasons, except in the case of small crayfish (<25 mm OCL), which become nocturnal in summer when the time of their peak activity changes from around midday, to around midnight. We suggest that this general pattern of diurnal activity may be a predator-avoidance strategy, as many carnivorous Australian mammals are nocturnal. The nocturnal activity patterns seen in small crayfish during summer may also be a predator-avoidance strategy, but the diurnal predators in this case could be the large crayfish, which are active only in the summer.
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Conference Title
Freshwater Crayfish
Volume
15
Issue
1
Subject
Biological Sciences
Zoology