ISSN:
1573-5117
Keywords:
fish-predation
;
roach
;
Bosmina
;
body-size
;
eye-size
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Prey selection mechanisms of juveniles of the particulate feeding roach (Rutilus rutilus) were tested in bag experiments in lake Gjersjøn. Cladocerans and large developmental stages (cop. IV-ad.) of copepods were consumed in large numbers both in the bags added fish and in lake, while rotifers increased in numbers in bags added fish. The effect of fish predation on the small cladoceran Bosmina longirostris was tested by comparing morphological structures in fish-free bags and bags added fish. The results strongly support the visibility selective hypothesis, as eye-diameter became significantly smaller in bags added fish (P 〈 0.05, T-test), while body-size, length of antennae and mucro, frequency and number of eggs were slightly or unsignificantly correlated with presence or absence of fish. Further, while roach was found to consume large numbers of Bosmina longirostris, the far greater but nearly unpigmented Asplanchna priodonta was never consumed. Additionally, other data further supporting the visibility-selective hypothesis are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00011400
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