The Extent of Great Crested Grebe Predation on Bleak in Lake Como, Italy

Martinoli, Adriano; Gagliardi, Alessandra; Preatoni, Damiano; Martino, Silvia Di; Wauters, Luc A.; Tosi, Guido

doi:10.1675/1524-4695(2003)026[0201:teogcg]2.0.co;2

Cited by 12 publications

(10 citation statements)

References 8 publications

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“…Piersma et al 1988Martinoli et al 2003Gagliardi et al 2007). Anyway, the pelagic fish biomass in Lake Maggiore is constituted primarily by whitefish, which is, therefore, a very probable prey of great crested grebe.…”

Section: Comparison Of Oc's Patterns In Fish and Fish-eating Birdmentioning

confidence: 99%

Age-Dependent Bioaccumulation of Organochlorine Compounds in Fish and their Selective Biotransformation in Top Predators from Lake Maggiore (Italy)

Volta¹,

Tremolada

Neri

et al. 2008

Water Air Soil Pollut

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Fish and piscivorous bird eggs collected in 2003 from Lake Maggiore (Italy), were analysed for PCB and DDT contamination. Lake Maggiore has been severely polluted by DDT through production of the pesticide within its catchment. Although agricultural application of DDT was banned in Italy in the 1978, industrial production continued until 1996, with enough contamination of water and soil for serious bioaccumulation in the lake biota. PCB and DDT concentrations in a whitefish (Coregonus macrophthalmus Nusslin 1882) were seen to be dependent on season and fish age, but not on sex. The average increase of the lipid-normalised concentration of DDTs and PCBs was two-fold across season and also across age, resulting in an overall increase of four fold. The seasonal variation was related to the ecophysiological cycle of the fish and to the contamination dynamic of the lake, while the effect of the fish age was explained on the base of biomagnificationrelated mechanisms. A fugacity model was applied to predict the age-dependent bioaccumulation potential of PCBs, whose concentrations were rather stable in recent years in the lake. Predicted values for compounds with negligible biotransformation were in good agreement with experimental data (calculated vs. experimental mean difference of 14%), and a relationship between the increase of experimental agedependent concentration and K ow was observed. The good correspondence between the predicted and the measured values for most PCB congeners confirmed the general inability of fishes to biotransform these compounds. On the contrary, the importance of biotransformation processes was recognised in birds; eggs of a fish eating bird (Podiceps cristatus) from the same area selectively bioaccumulated p,p′-DDE. For PCBs, congener 149 appears to be completely metabolized by the bird species, and congeners 95, 101, 132, 151 and 174 were reduced as well. The role of the meta-para free position on at least one phenyl ring of PCB congeners in biotransformation processes was confirmed.

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Section: Comparison Of Oc's Patterns In Fish and Fish-eating Birdmentioning

confidence: 99%

Age-Dependent Bioaccumulation of Organochlorine Compounds in Fish and their Selective Biotransformation in Top Predators from Lake Maggiore (Italy)

Volta¹,

Tremolada

Neri

et al. 2008

Water Air Soil Pollut

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“…As in other parts of their European range (Hanzak, 1952;Madsen, 1957;Cramp & Simmons, 1977;Doornbos, 1984;Buttiker, 1985), grebes wintering on lakes in N Italy fed nearly exclusively on fish (99% of food remains were from fish, against only 1% from insects and crustaceans). Earlier studies on Lake Varese (Bianchi, 1962) and Lake Como (Gagliardi, 2003;Martinoli et al, 2003) found that bleak was the most important prey of wintering grebes. This was confirmed by our data gathered on more Prealpine lakes, where 78% of all fish prey was bleak, which constituted almost 90% of the diet in terms of ingested fish mass.…”

Section: Discussionmentioning

confidence: 95%

From mass of body elements to fish biomass: a direct method to quantify food intake of fish eating birds

et al. 2007

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The winter diet of great crested grebe\ud (Podiceps cristatus) was studied in the major lakes\ud of Insubria region, N Italy, in 2000–2003 by\ud analysing stomach and oesophagus contents of\ud birds found dead. Winter diet of cormorant\ud (Phalacrocorax carbo) was studied using pellet\ud analysis. Diet was expressed in terms of numerical\ud abundance, frequency and biomass of prey. A\ud detailed methodology is described of how to\ud prepare a reference collection of otoliths, pharyngeal\ud bones and chewing pads (key-elements),\ud essential for species-specific identification of fish\ud remains in stomachs and pellets, and to estimate\ud ingested fish biomass. Correlations between mass\ud (mg) of key-elements and mass of corresponding\ud fish were significant, and exponential regression\ud models were used to calculate biomass of each\ud single prey item directly from the mass of its\ud key-elements. Advantages of this method are\ud compared with the more traditional two step\ud approach in which size of elements is used to\ud estimate fish length, followed by calculating fresh\ud mass from fish length. Cyprinids formed the\ud largest part of the diet for both predators. Great\ud crested grebes selected small prey, feeding mainly\ud on bleak (Alburnus alburnus alborella), while diet\ud composition of cormorants varied significantly in\ud relation to prey availability

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“…In reviewing the indicator value of birds, species such as the Great Crested Grebe have been mentioned as characteristic eutrophication indicators. The local and global changes in distribution, abundance and breeding behaviour exhibited by this species (Rutschke, 1987;Stanevicius, 2001;Martinoli et al, 2003), are in many cases attributed, at least partially, to changes in the trophic status of wetlands. Our results support the idea that this species and the Black-necked Grebe are the most closely dependant on local trophic conditions, at least during some phases of nutrient increase.…”

Section: Discussionmentioning

confidence: 99%

Aquatic birds as bioindicators of trophic changes and ecosystem deterioration in the Mar Menor lagoon (SE Spain)

et al. 2005

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The Mar Menor is the largest coastal lagoon in the Western Mediterranean and it is an important site for wintering and breeding waterfowl. During recent decades several hydrological and land-use changes in the watershed have increasingly threatened the conservation of the lagoon due to the development of urban areas, tourism and agriculture. A dynamic system model has been developed at the watershed scale to estimate the annual load of nutrients reaching the Mar Menor-associated wetlands. At present, mean annual loadings of approximately 2000 tonnes of nitrogen and 60 tonnes of phosphorus are delivered to the lagoon. The simulation results emphasize the role of heavy rainfall events and floods in the formation of the total nutrient load.

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The Extent of Great Crested Grebe Predation on Bleak in Lake Como, Italy

Cited by 12 publications

References 8 publications

Age-Dependent Bioaccumulation of Organochlorine Compounds in Fish and their Selective Biotransformation in Top Predators from Lake Maggiore (Italy)

Age-Dependent Bioaccumulation of Organochlorine Compounds in Fish and their Selective Biotransformation in Top Predators from Lake Maggiore (Italy)

From mass of body elements to fish biomass: a direct method to quantify food intake of fish eating birds

Aquatic birds as bioindicators of trophic changes and ecosystem deterioration in the Mar Menor lagoon (SE Spain)

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