Diel vertical migrations of invertebrate predators (Leptodora kindtii ,Thermocyclops taihokuensis, andMesocyclops sp .) in a shallow, eutrophic lake

Abstract

We studied vertical distribution patterns of three invertebrate predators -Leptodora kindtii, Mesocyclops sp., and Thermocyclops taihokuensis -in a shallow eutrophic lake, Lake Suwa, Japan. From June to October in 2000 and 2001, we collected samples in the lake center in order to examine the vertical distribution patterns and the densities of the predators in the water column during the day (0900) and at night (2330). We also examined phototactic behavior of Leptodora in the laboratory. The three invertebrate predators showed clear migration patterns. Leptodora and Thermocyclops displayed a typical migration, avoiding the surface and maintaining a high abundance in deeper water during the day, and being distributed uniformly during the night. Mesocyclops, on the other hand, showed no clear vertical distribution pattern in the water column. However, Mesocyclops showed higher densities in the water column during the night than during the day. It suggests that they stayed just above the bottom during the day and migrated upward during the night. Leptodora also showed such a density difference between day and night. In the laboratory, Leptodora showed strong negative phototactic behavior. The observed density changes between day and night in Leptodora and Mesocyclops suggests the possible underestimation of their population density by usual sampling methods, and thus the impact of predation on populations of prey zooplankton species may also be underestimated in shallow water bodies.

Diel vertical distribution of planktonic microcrustaceans (Crustacea: Cladocera, Copepoda) in a natural shallow lake from Transylvania, Romania

“…The existence of DVM for cladocerans and adult copepods was clearly showed by higher night biomass values, in some cases twice as large as daytime values. Similar findings were reported in the literature; Chang and Hanazato (2004) for example observed higher densities of Leptodora kindtii and Mesocyclops in the water column of a shallow temperate lake during the night than during the day. These biomass differences between day and night suggest that both cladocerans and adult copepods stayed just above the bottom during the day, avoiding sampling, and migrated upward during the night.…”

“…These preferences depend on temperature (Gliwicz and Pijanowska, 1988;Haney 1993), dissolved oxygen (Horppila et al, 2000;Chang and Hanazato, 2004), while the changes in light intensity are known to be the primary cue for vertical migrations (Ringelberg et al, 1991;Ringelberg and Van Gool, 2003). The vertical distribution of zooplankton may be caused by a complex of factors including not only abiotic ones, like temperature, but also biotic drivers, like food availability and quality (Jakobsen and Johnsen, 1987;Leibold, 1990;Lampert et al, 2003;Pearre, 2003), predation (Beklioglu et al, 2008) or competition (Larsson, 1997).…”

Diel dynamics of heleoplankton in relation to some physico-chemical attributes of water in an aquaculture tank in Guwahati, Assam

“…3). Chang and Hanazato (2004) also reported a two or three times increase of Mesocyclop sp. density at the midnight hours over the day time density.…”

Impacts des coupes forestières sur l'alimentation de l'omble de fontaine (Salvelinus fontinalis) et la structure trophique de lacs en forêt boréale /

“…Ces organismes sont les plus gros représentants zooplanctoniques des lacs de la forêt boréale et présentent des migrations journalières verticales qui constituent une adaptation à la prédation par les poissons (Lampert 1989, Dawidowicz et al 1990, Chang et al 2004 Les analyses d'isotopes stables se sont avérées être toutes indiquées afin d'évaluer les impacts de la coupe sur la structure trophique des lacs à l'étude. La matière organique particulaire semble présenter un appauvrissement en isotope stable de carbone associé à la coupe forestière.…”