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A Quantitative Comparison of Two Zooplankton Sampling Methods, a Plankton Trap and a Towed Net, in the Baltic
Author(s) -
Kankaala Paula
Publication year - 1984
Publication title -
internationale revue der gesamten hydrobiologie und hydrographie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 0020-9309
DOI - 10.1002/iroh.19840690218
Subject(s) - zooplankton , plankton , trap (plumbing) , environmental science , biomass (ecology) , sampling (signal processing) , zoology , biology , oceanography , fishery , ecology , physics , environmental engineering , geology , detector , optics
A comparison between a large plankton trap with a capacity of 23 litres and a modern towed net was made in the course of zooplankton production studies in the Baltic. On the average, the net efficiency was 75% of that of the trap. Both methods were equally efficient in catching naupliar stages of copepods. The net efficiency was especially low during the zooplankton maximum for adult copepods and cladocerans (41 and 51%, respectively), probably due to the active avoidance of the net by fast swimming species. The net was only about 66% as efficient as the trap for catching rotifers. This difference is probably caused by the loss of small and softbodied forms through the mesh. Only about 65% of the total zooplankton biomass retained in the trap was collected by the net. Net sampling is not recommended for quantitative zooplankton studies.