scholarly journals Impact of juvenile cyprinid fish predation on the food availability and zooplankton community

1991 ◽  
Vol 24 (4) ◽  
pp. 2519-2522
Author(s):  
István Tátrai ◽  
Judit Padisák ◽  
Simonian Aschot
2011 ◽  
Vol 101 (1-2) ◽  
pp. 75-84 ◽  
Author(s):  
Juliana D Dias ◽  
Érica M Takahashi ◽  
Natália F Santana ◽  
Cláudia C Bonecker

We investigated the impact of fish cage culture on the zooplankton community structure in a tropical reservoir. We hypothesized that community abundance is greater near cages and increases over time due to the increase in food availability. Samplings were performed near, upstream and downstream from net cages, and before and after net cage installation. The abundance of zooplankton increased 15 days after the experiment was set up, followed by a reduction and finally increased. Rotifer abundance showed significant differences among sites (p<0.05) and sampling periods (p<0.001). Significant differences were also observed in total zooplankton and cladoceran abundance (p<0.001). The spatial and temporal variation of the physical and chemical variables were indirectly correlated with the structure and dynamic of the zooplankton community, as they indicated the primary production in the environment. Our hypothesis was rejected, since the zooplankton was abundant at the reference site. Only rotifers showed higher abundance near cages, due to the influence of food availability. Community dynamics during the experiment was also correlated to food availability. Our results suggest an impact of fish farming on the zooplankton community.


Crustaceana ◽  
2015 ◽  
Vol 88 (10-11) ◽  
pp. 1193-1199 ◽  
Author(s):  
Patricio De los Ríos-Escalante

The zooplankton assemblages in Chilean lakes are characterized by their markedly low species numbers and dominance of calanoid copepods. Nevertheless, the effects of zooplanktivorous fish predation on zooplankton size in these communities have not yet been studied in detail. The aim of the present study was to analyse the total length in the main groups of zooplanktonic crustaceans in Chilean lakes: Copepoda: Calanoida, and Cladocera: Daphniidae, as well as “small cladocerans” (specifically the families Bosminidae and Chydoridae). The results revealed that in the presence of fish, total body length decreased significantly for calanoid copepods, whereas for other groups that presence has no significant effect. In sites with fishes, daphniids are significantly larger in comparison with the other groups of the zooplankton community, whereas in sites without fishes calanoids are significant larger in comparison with those other groups. These results would indicate that calanoids would be the main prey for zooplanktivorous fishes in Chilean lakes. Similar results have been reported for Argentinean Patagonian lakes.


2007 ◽  
Vol 67 (2) ◽  
pp. 251-262 ◽  
Author(s):  
CWC. Branco ◽  
B. Kozlowsky-Suzuki ◽  
FA. Esteves

The Imboassica lagoon, located in the Municipality of Macaé (RJ), is separated from the sea by a sand bar, and its surroundings are partially occupied by residential areas. This coastal lagoon has undergone environmental degradation due to sewage input and artificial sand bar openings. The temporal and spatial variation of environmental variables and zooplankton were studied monthly for four years. There were five artificial openings of the sand bar during the period of study, mostly in the rainy season. Besides osmotic changes, these events caused the drainage of the water of the lagoon into the sea, loss of total organic nitrogen, and an increase of total phosphorus. The zooplankton community of Imboassica lagoon included freshwater and marine taxa, holoplanktonic, meroplanktonic and nectobenthonic forms. Polychaeta, Bivalvia and Gastropoda larvae, and the taxa of Rotifera Hexarthra spp., Lecane bulla, Synchaeta bicornis, nauplii of Cyclopoida and Calanoida copepods were considered constant taxa. Distinct zooplankton assemblages were found during zooplankton spatial surveys in oligohaline and mesohaline conditions. The successful zooplankton populations were either favored by the disturbance of the sand bar opening, such as the veligers of the gastropod Heleobia australis, or capable of fast recovery after the closing of the sand bar, during the succession from a marine into an oligohaline environment, such as Hexarthra spp.. Such populations seemed well adapted to the stress conditions usually found in the lagoon due to osmotic changes, column mixing, nutrient input, and high fish predation pressure. Rare species in the community, such as Moina minuta, presented population increases all over the lagoon under oligohaline conditions.


Crustaceana ◽  
2017 ◽  
Vol 90 (14) ◽  
pp. 1793-1802
Author(s):  
Patricio R. De los Ríos Escalante ◽  
Fatima Kies

The Patagonian lakes (38-55°S) are characterized by their marked oligotrophy, low number of species of crustacean zooplankton, and a marked predominance of calanoid copepods. Within this context, we considered that a review about the ecology of the zooplankton in central and southern Chilean lakes would be useful, aiming to understand the ecological importance of this group. Data obtained from the literature for freshwater bodies in central and southern Chilean lakes were analysed. In addition, data from various bays with widely differing trophic status in Llanquihue Lake were examined. The results revealed the existence of originally pristine and oligotrophic sites, all with a low number of species and marked calanoid dominance. However, in northern Patagonia there are many lakes in which human intervention has caused an increase in phytoplankton activity, with a consequent replacement of calanoid copepods by daphniid cladocerans. Other important factors that could affect the zooplankton community would be fish predation, which is due to generate a decrease in large-bodied groups of zooplankton; and stress due to exposure to natural ultraviolet radiation. Ecological, biogeographical, and evolutionary topics are discussed within the framework described.


Oecologia ◽  
1985 ◽  
Vol 67 (2) ◽  
pp. 218-219 ◽  
Author(s):  
Erik H. ten Winkel ◽  
C. Davids

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 597
Author(s):  
David Carrozzo ◽  
Simona Musazzi ◽  
Andrea Lami ◽  
Francisco E. Córdoba ◽  
María de los Ángeles González Sagrario

Shallow lakes are vulnerable ecosystems impacted by human activities and climate change. The Cladocera occupy a central role in food webs and are an excellent paleoecological indicator of food web structure and trophic status. We conducted a paleolimnological study in Lake Blanca Chica (Argentina) to detect changes on the planktivory and herbivory regimes over the last 250 years. Generalized additive models were fitted to the time series of fish predation indicators (ephippial abundance and size, mucrone size, fish scales, and the planktivory index) and pheophorbide a concentration. The cladoceran assemblage changed from littoral-benthic to pelagic species dominance and zooplankton switched from large-bodied (Daphnia) to small-bodied grazers (Bosmina) ca. 1900 due to increased predation. The shift in planktivory regime (ca. 1920–1930), indicated by fish scales and the planktivory index, as well as herbivory (ca. 1920–1950), was triggered by eutrophication. Changes in planktivory affected the size structure of Bosmina, reducing its body size. This study describes the baseline for the lake as well as the profound changes in the composition and size structure of the zooplankton community due to increased predation and the shift in the planktivory regime. These findings will provide a reference status for future management strategies of this ecosystem.


1984 ◽  
Vol 35 (4) ◽  
pp. 417 ◽  
Author(s):  
MC Geddes

Zooplankton was quantitatively collected from Lake Alexandrina from November 1975 until March 1978. Twenty-eight species of zooplankton were identified, although momentary species composition usually comprised two calanoids, one cyclopoid, from three to six cladocerans and from zero to four rotifers. There were no consistent patterns in the vertical or horizontal distribution of the major zooplankters. Some species, including Boeckella triarticulata, Calarnoecia ampulla, Bosrnina meridionalis, Ceriodaphnia quadrangula and possibly Daphnia carinata were perennial, whereas Diaphanosorna unguiculaturn, Moina rnicrura and Daphnia lumholtzi were seasonal. Zooplankton density was relatively high and constant throughout the study. The zooplankton community included both large and small species. In Lake Alexandrina, high turbidity may preclude size-selective fish predation, allowing the persistence of large species, while invertebrate predation may be insufficient to remove small species.


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