Chaoborus populations: response to food web manipulation and potential effects on zooplankton communities

1987 ◽  
Vol 65 (12) ◽  
pp. 2846-2852 ◽  
Author(s):  
Monica M. Elser ◽  
Carl N. von Ende ◽  
Patricia Sorrano ◽  
Stephen R. Carpenter

Chaoborus populations were studied in two lakes in which fish predation was experimentally reduced, and in a reference lake. In Tuesday Lake, major reduction of fish predation led to substantial increases in density of Chaoborus punctipennis. Analysis of crop contents and estimates of consumption rates suggested that C. punctipennis caused declines of rotifer and copepod populations following the manipulations. In Peter Lake, lesser changes in fish predation caused no major change in density of Chaoborus flavicans, perhaps because food limitation compensated for effects of reduced predation. In both Peter Lake and the reference lake, Paul Lake, C. flavicans preyed heavily and selectively on Daphnia less than about 1.4 mm in total length. Bioenergetic calculations indicated that up to 46% of the daphnids were consumed daily. At some times of the year, certain zooplankton populations (especially noncolonial rotifers, small copepods, and small cladocerans) were strongly influenced by Chaoborus predation.

1986 ◽  
Vol 43 (1) ◽  
pp. 154-159 ◽  
Author(s):  
Marlene S. Evans

Summer Zooplankton communities in the inshore region of southeastern Lake Michigan were dominated by small species during the 1970s, suggesting that size-selective fish predation pressures were intense. Abundances of alewife (Alosa pseudoharengus), the dominant planktivore in the 1970s, declined in recent years, especially over 1982–84. Despite decreased alewife predation, small zooplankton taxa continued to predominate. Moreover, zooplankton standing stocks declined 10-fold during 1982–84, suggesting that predatory pressures had intensified. Concurrent with the alewife population decrease was a major increase in yellow perch (Perca flavescens) abundances. As a probable consequence of intense predation pressures exerted by abundant yellow perch, zooplankton standing stocks were severely reduced. Yellow perch populations may have been adversely affected by food limitation, especially in summer 1984 when zooplankton standing stocks were only 3% of their average level over 1975–81.


1997 ◽  
Vol 54 (3) ◽  
pp. 637-646 ◽  
Author(s):  
J M Fischer ◽  
T M Frost

A twofold increase in Chaoborus punctipennis abundance following experimental acidification of one basin of Little Rock Lake, Wisconsin, provided an opportunity to examine the hypotheses that C. punctipennis dynamics were regulated by (i) food resources for instars I and II, (ii) fish predation on instars III and IV, and (iii) invertebrate predation on instars I and II. Neither food limitation nor fish predation appeared to be important constraints on C. punctipennis abundance. Although rotifer biomass increased significantly during the acidification, C. punctipennis did not respond in a consistent manner to variation in food availability. Bioenergetics estimates of C. punctipennis consumption by rock bass (Ambloplites rupestris), the most acid-sensitive fish species, were small compared with C. punctipennis production. In contrast, invertebrate predation appeared to be an important constraint on C. punctipennis abundance. Chaoborus punctipennis abundance increased dramatically when abundance of the predator Mesocyclops edax declined to near zero. Comparison of M. edax predation rates and first instar production suggested that M. edax could exert strong predation pressure on C. punctipennis Thus, invertebrate predation may create a juvenile bottleneck for populations of small-bodied Chaoborus species in moderately productive acidified lakes.


Hydrobiologia ◽  
2020 ◽  
Vol 847 (21) ◽  
pp. 4503-4523 ◽  
Author(s):  
Jukka Ruuhijärvi ◽  
Tommi Malinen ◽  
Kirsi Kuoppamäki ◽  
Pasi Ala-Opas ◽  
Mika Vinni

AbstractWe studied the responses of a food web, especially fish and zooplankton, to summertime aeration, pumping of oxygen-rich epilimnetic water to the hypolimnion in Lake Vesijärvi, southern Finland. The aim of hypolimnetic aeration was to reduce internal loading of phosphorus from sediment. The population of smelt (Osmerus eperlanus L.), the main planktivore of the pelagial area, collapsed during the two 1st years of aeration due to increased temperature and low oxygen concentrations in the hypolimnion. The population recovered after the 4th year of hypolimnetic aeration, when oxygen conditions were improved. Despite elevated hypolimnetic temperature, smelt reached exceptionally high abundance, which led to a significant reduction in cladoceran body size. The density of perch (Perca fluviatilis L.) increased at first, but then decreased when the proportion of smelt and cyprinids increased. Biomasses of Daphnia decreased probably as a result of the disappearance of dark, low-oxygen deep-water refuge against fish predation and low availability of nutritionally high-quality algae. Occasionally filamentous cyanobacteria, such as turbulence tolerant Planktothrix agardhii (Gomont), were abundant, suggesting deteriorated food resources for zooplankton. The responses of food web were controversial with respect to the aim of the management, which was to prevent the occurrence of harmful algal blooms.


2020 ◽  
Vol 196 ◽  
pp. 110497 ◽  
Author(s):  
María Florencia Gutierrez ◽  
Florencia Rojas Molina ◽  
Diego Frau ◽  
Gisela Mayora ◽  
Yamila Battauz

2014 ◽  
Vol 71 (7) ◽  
pp. 1039-1049 ◽  
Author(s):  
Kevin N. McDonnell ◽  
Brian M. Roth

We developed a bioenergetic-based foraging model to evaluate how the composition of the pelagic zooplankton community influences the growth of zooplanktivorous larval walleye (Sander vitreus). Our model incorporates field observations of pelagic zooplankton composition and density as well as size-specific prey preferences of larval walleye to simulate both foraging and consumption rates. The model was evaluated in four lakes in northern Wisconsin: two with invasive populations of rainbow smelt (Osmerus mordax) and two without populations of rainbow smelt. Invasive rainbow smelt are known to alter the composition of pelagic zooplankton communities as well as cause declines in walleye recruitment, thus providing a unique opportunity to evaluate our model. The results suggest that larval walleye growth is slowed in systems that lack high densities of large-bodied Daphnia. Such conditions may create an energetic bottleneck for larval walleye. This approach could easily be applied to other species that are also affected by rainbow smelt or more generally where success of larval foraging is suspected to have a large influence on year-class strength.


2014 ◽  
Vol 48 (4) ◽  
pp. 367-378 ◽  
Author(s):  
Susanne Worischka ◽  
Claudia Hellmann ◽  
Thomas U. Berendonk ◽  
Carola Winkelmann

2012 ◽  
Vol 90 (7) ◽  
pp. 903-914 ◽  
Author(s):  
C.J. Harvey ◽  
T.P. Good ◽  
S.F. Pearson

Conservation of predators presents challenges when predators affect prey populations that provide ecosystem services. Near Puget Sound, resident and overwintering populations of Bald Eagle ( Haliaeetus leucocephalus (L., 1766)) have expanded in recent decades. We modeled the potential impact of Bald Eagles on marine food-web structure. Bald Eagles caused trophic cascade dynamics through mid-level predators (seabirds) to lower trophic levels (fishes, benthic invertebrates), particularly when seabirds were more abundant in eagle diets. Resident Bald Eagles affected food-web structure more than overwintering eagles, despite the latters’ greater abundance. Predator avoidance behavior by nearshore diving birds and herbivorous birds exacerbated trophic cascade effects, but only in a narrow range of species. Variability in the number of overwintering Bald Eagles, which come to the area to feed on salmon carcasses (primarily chum salmon, Oncorhynchus keta (Walbaum in Artedi, 1792)), had little effect on the food web. Our results indicate that Bald Eagles are important to marine food-web structure, owing to their high consumption rates and the high consumption rates of their seabird prey, but uncertainty about eagle diets limits our full understanding of their impact. In systems where Bald Eagles affect large seabird breeding colonies, their role in food-web structure is likely greater.


10.2307/4972 ◽  
1987 ◽  
Vol 56 (3) ◽  
pp. 1086
Author(s):  
D. G. George ◽  
L. Lampert

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