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Haywood, Carl N. (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume 75 (1987)

Rudsam, Lars G.; Trapp, Todd W.
Diel patterns of behavior and habitat utilization of cisco (Coregonus artedii) in two Wisconsin lakes,   pp. 70-78 PDF (3.4 MB)

Page 77

Diel Patterns of Cisco 
dawn. Engel and Magnuson (1976) sug- feeding peak. Cisco in Trout Lake apgested
that the opposing movements of peared to feed both day and night. This is
the two species enhanced spatial niche in accordance with laboratory experiseparation.
In July 1981, pelagic perch ments by Janssen (1980) on cisco feeding were
rare (only four perch were caught in both in light and in darkness. The fish
the gill nets), and cisco did not migrate were size-selective and more efficient
in horizontally, light. However, feeding occurred in dark- 
 Vertical did migrations did not occur ness even at the lowest prey density
tested even though cisco were not restricted by (16 Daphnia/l). The fish
were then high temperatures and low oxygen levels nonselective. As Janssen
points out, the to a narrow depth layer in Trout Lake. possible effect of
cisco predation on This differs from observations on vendace zooplankton
communities depends on the (Coregonus albula, a related Eurasian time of
day they feed. This predator-prey cisco), which is generally reported to
interaction is further complicated when migrate vertically (Northcote and
Rund- did patterns of habitat utilization exist berg 1970, Dembinski 1971,
Nilsson 1979, (e.g. younger cisco in Trout Lake). Cisco Endenlein 1982, Hamnin
1986). Vendace may act as daytime size-selective planktifeed primarily during
daylight hours vones in pant of a lake and as nighttime (Nilsson 1979, Endenlein
1982) and may nonselective planktivores in other areas. 
increase the length of its feeding period by 
migrating toward the surface at dusk. Acknowledgments Since cisco can feed
at night (Engel 1976, 
We wish to thank John Lyons and 
Janssen 1980), did vertical migrations 
may be less advantageous. Timothy Kratz for their help during field 
Although the did migration patterns of sampling. Stanley Dodson and John
cisco and vendace differed, both species Neess gave advice on zooplankton
iddntification and stomach analysis pro- 
show intra-specific habitat segregation 
cedures. John Magnuson and Hannah 
between age groups (Rudstam and MagHill improved the manuscript. The study
nuson 1985, Hamnin 1986). The similarity 
in diet of different cisco age groups (Table was supported by the Long Term
Ecological Research Project at the University 
4) indicates that this segregation was not of Wisconsin-Madison (NSF grant
due to an age-specific preference for dif8012313, John Magnuson principal
inferent food items that may have been difvestigator). 
ferentially distributed in space. Different 
size groups of vendace also have similar 
diets (Hamnin 1983). Hamnin (1986) sug- Works Cited 
gested that younger vendace are more ef- Baumann, P. C., and J. F. Kitchell.
1974. Diel ficient planktivores than larger vendace patterns of distribution
and feeding of and that larger fish therefore avoid bluegill (Lepomis macrochirus)
in Lake younger fish to decrease intma-specific Wingra, Wisconsin. Trans.
Am. Fish. Soc. 
food competition. 103:255-260. 
Engel (1976) reported cisco as feeding Blaxter, J. H. 5. 1970. Light. Animals.
Fishes. In Marine Ecology vol. 1, ed. 0. Kinne. 
during the night, and Emery (1973) 
 London: Wiley-Interscience. 213—320. 
classified this species as a nocturnal Brabrand, A., B. Faafeng, and T. Kallqvist.
planktivone. However, neither of these 1984. Can iron defecation from fish
intwo studies compared fish caught during fluence phytoplankton production
and bioday and during night. Our somewhat mass in eutrophic lakes? Limnol.
Oceanogr. limited data does not support a nocturnal 29:1330-1334. 

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