J. Karjalainen et al., COMPARISON OF METHODS USED IN ZOOPLANKTON SAMPLING AND COUNTING IN THE JOINT RUSSIAN-FINNISH EVALUATION OF THE TROPHIC STATE OF LAKE-LADOGA, Hydrobiologia, 322(1-3), 1996, pp. 249-253
The results of a joint Russian-Finnish investigation on zooplankton in
Lake Ladoga are presented, and a comparison is made between two sampl
ing techniques, tube sampler and plankton net, and between two countin
g methods. The precision of subsampling and sampling is further discus
sed on the basis of zooplankton data gathered in Lake Saimaa, Finland.
The comparison clearly indicates that a tube sampler is required for
reliable sampling of small-sized animals, while a plankton net saves t
ime and is a more economical sampler for large, rare or active animals
. The comparison between the results obtained by Finnish and Russian w
orkers, using different counting procedures, shows that the main group
s of crustacean zooplankton are similarly counted and identified in th
e two laboratories.