Trophic changes, without changes in the external nutrient loading

Henrikson, Lennart; Nyman, Hans G.; Oscarson, Hans G.; Stenson, Jan A. E.

doi:10.1007/bf00018835

Cited by 143 publications

(64 citation statements)

References 14 publications

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“…In other lake restoration programmes a decline in nutrient concentrations was observed after removal of planktivorous fishes (Stenson et al, 1978 ;Henrikson et al, 1980 ;Shapiro & Wright, 1984). In these lakes fishes were eliminated by rotenone .…”

Section: Discussionmentioning

confidence: 93%

Restoration by biomanipulation in a small hypertrophic lake: first-year results

Donk¹,

Gulati²,

Grimm³

1990

Hydrobiologia

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Biomanipulation was carried out in order to improve the water quality of the small hypertrophic Lake Zwemlust (1 .5 ha ; mean depth 1 .5 m) . In March 1987 the lake was drained to facilitate the elimination of fish . Fish populations were dominated by planktivorous and benthivorous species (total stock c . 1500 kg) and were collected by seine-and electro-fishing . The lake was subsequently re-stocked with 1500 northern pike fingerlings (Esox lucius L .) and a low density of adult rudd (Scardinius erythrophthalmus). The offspring of the rudd served as food for the predator pike . Stacks of Salix twigs, roots of Nuphar lutea and plantlets of Chara globularis were brought in as refuge and spawning grounds for the pike, as well as shelter for the zooplankton .The impact of this biomanipulation on the light penetration, phytoplankton density, macrophytes, zooplankton and fish communities and on nutrient concentrations was monitored from March 1987 onwards . This paper presents the results in the first year after biomanipulation .The abundance of phytoplankton in the first summer (1987) after this biomanipulation was very low, and consequently accompanied by increase of Secchi-disc transparency and drastic decline of chlorophyll a concentration .The submerged vegetation remained scarce, with only 5 % of the bottom covered by macrophytes at the end of the season .Zooplankters became more abundant and there was a shift from rotifers to cladocerans, comprised mainly of Daphnia and Bosmina species, the former including at least 3 species .The offspring of the stocked rudd was present in the lake from the end of August 1987 . Only 19% of the stocked pike survived the first year.Bioassays and experiments with zooplankton community grazing showed that the grazing pressure imposed by the zooplankton community was able to keep chlorophyll a concentrations and algal abundance to low levels, even in the presence of very high concentrations of inorganic N and P . The total nutrient level increased after biomanipulation, probably due to increased release from the sediment by bioturbation, the biomass of chironomids being high .At the end of 1987 Lake Zwemlust was still in an unstable stage . A new fish population dominated by piscivores, intended to control the planktivorous and benthivorous fish, and the submerged macrophytes did not yet stabilize .

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Section: Discussionmentioning

confidence: 93%

Restoration by biomanipulation in a small hypertrophic lake: first-year results

Donk¹,

Gulati²,

Grimm³

1990

Hydrobiologia

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“…Henrikson et al (1980) reported that the beneficial effects lasted for at least 4 years, but their lake was kept free offish. Round Lake, in contrast, was restocked with planktivores, piscivores and benthivores, and the effect has persisted, so far, for 2 years.…”

Section: Discussionmentioning

confidence: 99%

Lake restoration by biomanipulation: Round Lake, Minnesota, the first two years

Wright

1984

Freshwater Biology

499

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SUMMARY. 1. Rotenone was applied to Round Lake in the autumn of 1980 in order to eliminate predominantly planktivorous and benthivorous fish. The lake was subsequently restocked with a higher population density of piscivores. The effect of this biomanipulation on the phytoplankton and zooplankton communities and on total nutrient concentrations was monitored at fortnightly intervals during the summers, from May 1980 to September 1982. 2. The abundance of phytoplankton was much lower after biomanipulation and was consistent with observed changes in Secchi disc transparency, total attenuation coefficient and chlorophyll a concentration. Zooplankters were also less abundant in 1981 and 1982 but the decrease in numbers was more than offset by the large increase in the mean sizes of the zooplankters present, so that the estimated grazing pressures in 1981 and 1982 were at least double the 1980 value. 3. Daphnia, rare in 1980, became the dominant genus in 1981 and 1982, and a shift to progressively larger‐bodied Daphnia species was observed. 4. Although total nitrogen and total phosphorus levels were generally lower after biomanipulation, their decline could not explain the reduction in phytoplankton abundance which was attributed to the increased grazing pressure. Possible causes of the observed declines in nutrient concentrations are discussed.

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“…Biomass of macrophytes was negatively correlated to the biomass of Spirogyra (r, = -0.56, P < 0.002, n = 36). 1978;Henriksson et al 1980;Fott et al 1980), our study adds a third pathway. Fish grazing on macrophytes involves a transport of nutrients from the sediment to the water phase via macrophyte uptake of nutrients from the sediment.…”

mentioning

confidence: 95%

“…Hrbaeek 1962; Andersson et al 1978;Henriksson et al 1980;Fott et al 1980). Two main pathways by which fish may affect the trophic conditions of lakes have been suggested: predation by planktivorous fish depresses zooplankton abundance, allowing phytoplankton biomass to increase; and the feeding activity of fish on the bottom causes nutrients to be released from the sediment (Lamarra 1974;Andersson 198 1).…”

mentioning

confidence: 99%

Effects of fish grazing on nutrient release and succession of primary producers1

Hansson

Johansson

Persson

1987

Limnology & Oceanography

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Abstract-Macrophytes(Anacharis canadensis) growing in aquaria were eliminated by the grazing activity of the omnivorous rudd (Scardinius erythrophthalmus). The phosphorus content in both the water column and periphyton was greater in those aquaria that contained fish. Grazing activity of rudd caused 33P0,3-that was injected into the sediment and taken up by A. canadensis through their roots to be released into the water phase. In a pond experiment, grazing rudd reduced the biomass ofA. canadensis, which in turn caused the biomass of epiphytic algae to increase. We suggest that nutrients, which are taken up by macrophytes from the sediments, are released by grazing fish. This nutrient pathway may thus promote a succession from submersed macrophytes to other primary producers and accelerate the eutrophication process.

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Trophic changes, without changes in the external nutrient loading

Cited by 143 publications

References 14 publications

Restoration by biomanipulation in a small hypertrophic lake: first-year results

Restoration by biomanipulation in a small hypertrophic lake: first-year results

Lake restoration by biomanipulation: Round Lake, Minnesota, the first two years

Effects of fish grazing on nutrient release and succession of primary producers1

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