Issue Cover image

You need to login to your IAA account in order to access jounral PDFs.
Member Login

Freshwater Crayfish 6(1): 166-177 (1986)


Download: PDF (1.04 MB)

Population structure and gut contents of the crayfish Astacus astacus in two Finnish rivers

Westman K, Särkkä J, Pursiainen M and Sumari O  e-mail link

Published Online: 1/21/2020


The population structure and gut contents of Astacus astacus populations were studied in August 1969 and 1970 in two Finnish rivers, Jarvenpaankoski at Keuruu and Raudanjoki at Loppi. In Jarvenpaankoski, 195 crayfish (length range 13-124 mm) and in Raudanjoki 1309 crayfish (length range 14-105 mm) were collected using electric fishing. Females comprised 52.1% and 49.9% of the population in Jarvenpaankoski and Raudanjoki, respectively. Males comprised 47.9% and 50.1%. In Raudanjoki the males are apparently at least 3 to 4-years old when they reach sexual maturity, while the females are 4 to 5-years old. At Jarvenpaankoski the females evidently do not become sexually mature until they reach 6 years or more. In Jarvenpaankoski, the mean density of crayfish aged two summers or more was 0.4/m2 and in the best areas 5/m2. In Raudanjoki the mean density was 4.1/m2. In Jarvenpaankoski and Raudanjoki, plant food was found in 81% and 79% of the crayfish, respectively. The proportion of plant material in the individual animals averaged 33% in Jarvenpaankoski and 56% in Raudanjoki. In Jarvenpaankoski animal food was found in 67% of the examined guts while in Raudanjoki this figure was 57%. In Jarvenpaankoski and Raudanjoki animal food constituted 10% and 29% of the food, respectively. In both streams the most predominant types of animal food were insect larvae (Chironomidae, Trichoptera), bryozoans, molluscs and crayfish. As the crayfish grow, the frequency and amount of plant food seem to increase. The proportions of the various food components also change. Not one of the crayfish was observed to have eaten fish. Their major source of food seems to be plant matter, which has little importance as fish food. The food used to produce crayfish is thus largely based on material that would probably otherwise not be utilized.

Supplemental Documents

  • There are no supplementary documents for this article

CrossRef Logo

Cited By


How to Cite

Westman K, Särkkä J, Pursiainen M and Sumari O. (1986). Population structure and gut contents of the crayfish Astacus astacus in two Finnish rivers. Freshwater Crayfish 6(1):166-177. doi: 10.5869/fc.1986.v6.166



Author Information

Authorship information for this paper are currently unavailable.


Publication History

   Manuscript Submitted:

   Manuscript Accepted:

   Published Online: 1/21/2020

   Published in Print:



Funding Information

No specific funding statement is available for this article.






Member Login

Forgot Your Password?

Recover PW

Enter the e-mail address you used to
create your IAA account.
Return to Login
Back to Top