SS3.16 Lentic-Lotic Linkages in Freshwaters: Comparisons from Different Ecosystems
Date: Thursday, June 13, 2002
Location: Poster Session - VCC
 
Ala-OpasPI, University of Helsinki, Lammi Biological Station, Lammi, Finland, pasi.ala-opas@helsinki.fi
Huitu, E, K, University of Helsinki, Lammi Biological Station, Lammi, Finland, eeva.huitu@helsinki.fi
Mäkelä, S, M, University of Helsinki, Lammi Biological Station, Lammi, Finland, suvi.m.makela@helsinki.fi
Arvola, L, , University of Helsinki, Lammi Biological Station, Lammi, , lauri.arvola@helsinki.fi
 
RELATIONSHIP BETWEEN FISH AND ZOOPLANKTON IN A LAKE CHAIN
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The fish and zooplankton data set of this study consists of surveys in eight lakes (presenting all nutrient types) situating in Southern Finland. Zooplankton samples were collected four times per year during 1997-1998. Fish stock studies were performed between 1998 and 1999 using NORDIC survey nets (12 different mesh sizes in the same net). Copepods and water fleas are very important food for juvenile fishes and some fish species are zooplanktivorous for all of their lives. In some basins of remarkable catch per unit efforts (CPUE in g/net and individuals/net) of juvenile roaches and perches (basic species in Finnish lakes) the proportion of those crustacean groups seem to be small. Same kinds of effects were noticed when bleak and smelt CPUE:s were significant. On the other hand there was some evidence of higher relative amounts of copepods and water fleas in the lakes where roaches and perches were bigger in size and CPUE:s of zooplanktivorous species were minor.