The daily activity patterns of Euastacus sulcatus (Decapoda: Parastacidae) in southeast Queensland

  1. Furse JM 1,
  2. Wild CH 2,
  3. Sirotti S 3 and
  4. Pethybridge H 4
  • First Published (Online): .

Abstract

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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  • How to cite this article: Furse JM, Wild CH, Sirotti S and Pethybridge H (2006). The daily activity patterns of Euastacus sulcatus (Decapoda: Parastacidae) in southeast Queensland. Freshwater Crayfish 15(1): 139-147. doi: 10.5869/fc.2006.v15.139

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