scholarly journals The tapeworm Paradilepis scolecina (Rudolphi, 1819) (Cestoda: Cyclophyllidea) invasion in Great Cormorant [Phalacrocorax carbo sinensis (Blumenbach, 1798)] from the breeding colony in Lake Selment Wielki (northern Poland)

2011 ◽  
Vol 48 (1) ◽  
pp. 23-28 ◽  
Author(s):  
J. Dziekońska-Rynko ◽  
E. Dzika
Keyword(s):  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Breeding Colony ◽  
Northern Poland ◽  
Phalacrocorax Carbo Sinensis ◽  
Very High

AbstractThe intensity and extensity of infestation of cormorants (Phalacocorax carbo sinensis) from a colony in Lake Selment Wielki with the tapeworm Paradilepis scolecina (Rudolphi, 1819) was examined. The cormorants were shot in April, August and October 2006 and in August and September 2007. The extensity of infection in all the cormorants under study was very high — even reaching 100 %. The highest intensity of infestation was found in the birds shot in August — 4697 tapeworms per bird in 2006 and 2562 in 2007. The intensity of infestation in the birds which were shot in autumn was less than one-tenth of that found in the birds shot in summer. The lowest intensity of infestation was found in the spring of 2006 — 61 tapeworms per bird.

scholarly journals Great cormorant (Phalacrocorax carbo) predation on pikeperch (Sander lucioperca L.) in shallow eutrophic lakes in Poland

2017 ◽  
Vol 25 (2) ◽  
pp. 123-130 ◽  
Author(s):  
Piotr Traczuk ◽  
Andrzej Kapusta
Keyword(s):  
Length Distribution ◽  
Bird Species ◽  
Fish Populations ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Sander Lucioperca ◽  
Eutrophic Lakes ◽  
Breeding Colony ◽  
Great Cormorants

AbstractIncreases in the population abundance of the piscivorous great cormorant (Phalacrocorax carbo) has led to conflicts with fisheries. Cormorants are blamed for decreased fish catches in many lakes in Poland. The aim of this paper is to describe to role of pikeperch (Sander lucioperca) in the diet of cormorants nesting in a colony on the island in Lake Warnołty. Since the breeding colony is located in the vicinity of Lake OEniardwy, the largest lake in Poland, the cormorants use the resources in this lake. In 2009-2016, 18,432 regurgitated fish were collected, of which 593 were pikeperch. The share of pikeperch among fish collected in 2009-2012 did not exceed 2%, but from 2013 this increased substantially to maximum of 38.2% in 2015. The smallest pikeperch had a standard length of 8.4 cm, and the largest 42.5 cm. Pikeperch mean length differed by year, and the length distribution was close to normal. The sizes of the regurgitated pikeperch indicate that cormorants prey almost exclusively on juvenile specimens. The results of the present study indicate that cormorant predation has a significant impact on pikeperch populations in lakes in the vicinity of the colony, and the great cormorants are possibly a significant factor in the effectiveness of pikeperch management. When planning for the management of fish populations in lakes subjected to cormorant predation pressure, it should be borne in mind that predation by this piscivorous bird species impacts the abundance and size-age structure of fish populations.

scholarly journals Estimating the mortality caused by great cormorant predation on fish stocks: pikeperch in the Archipelago Sea, northern Baltic Sea, as an example

2016 ◽  
Vol 73 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Outi Heikinheimo ◽  
Pekka Rusanen ◽  
Katja Korhonen
Keyword(s):  
Age Groups ◽  
Total Mortality ◽  
Sensitivity Analyses ◽  
Fish Stock ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Fish Stocks ◽  
Archipelago Sea ◽  
Phalacrocorax Carbo Sinensis ◽  
The Impact

Estimates of the mortality rates caused by cormorants are needed to assess the impact on fish stock dynamics and fisheries. In this study, we calculated the annual instantaneous mortality caused by great cormorants (Phalacrocorax carbo sinensis) on young pikeperch (Sander lucioperca), using data from Archipelago Sea, southwestern coast of Finland. The pikeperch are vulnerable to cormorant predation mainly at the ages 2–4. The annual instantaneous mortality caused by cormorants was between 0.04 and 0.13, and the estimated effect on the pikeperch stock size at recruitment to the fishery ranged from 4% to 23%, respectively. The average annual cormorant-induced mortality accounted for 5%–34% of the total mortality in these age groups. The sensitivity analyses proved that the rates of mortality from other sources largely affect the estimated mortality from cormorant predation. In cases with strong fluctuations in the abundance of the prey fish stocks, ignoring the size and density dependence of the natural mortality may lead to overestimation of the importance of cormorants as competitors of fisheries.

Infestation of the black cormorants (Phalacrocorax carbo sinensis L. 1758) from the colony on the Selment Wielki, with the nematode Contracaecum rudolphii Hartwich, 1964 (Nematoda, Anisakidae)

2008 ◽  
Vol 37 (4) ◽  
Author(s):  
Janina Dziekońska-Rynko ◽  
Jerzy Rokicki
Keyword(s):  
Seasonal Changes ◽  
Phalacrocorax Carbo ◽  
Mean Values ◽  
Phalacrocorax Carbo Sinensis ◽  
Contracaecum Rudolphii ◽  
Very High

Infestation of the black cormorants (Seasonal changes in the intensity and prevalence of infestation of the black cormorants from the colony on Lake Selment Wielki were investigated. In 2006, the cormorants were procured in April, August, and October, while in 2007, they were collected in August and September. The prevalence of the infestation was very high and reached 100%. The highest intensity (mean values of 102.46 and 82.17 nematodes/bird in 2006 and 2007, respectively) was revealed in the cormorants shot in August. Intensity of infestation of those birds procured in autumn 2006 was more than twice that found in spring and one-fourth of that found in summer of that year. Similarly, in autumn of 2007, the birds' stomachs contained less than half of the number of nematodes recorded in summer of that year.

scholarly journals Impact of cormorant (Phalacrocorax carbo sinensis L.) colonies on microbial pollution in lakes

2013 ◽  
Vol 13 (3) ◽  
pp. 139-145 ◽  
Author(s):  
Piotr Klimaszyk ◽  
Piotr Rzymski
Keyword(s):  
National Park ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Phalacrocorax Carbo ◽  
Breeding Colony ◽  
Probable Number ◽  
Microbial Pollution ◽  
Phalacrocorax Carbo Sinensis ◽  
High Pollution ◽  
Over 40 Years

AbstractDuring 2009-2011 we investigated the effect of perennial and roosting cormorant (Phalacrocorax carbo sinensis) colonies on microbial pollution in 3 lakes: Góreckie (Greater Poland National Park), Chrzypsko (Greater Poland Province) and Ostrowiec (Drawa National Park). On Lake Góreckie cormorants formed a roosting colony (<200 individuals) that inhabited part of the lake shore. On Lake Chrzypsko a new breeding colony was formed (3 nests) while the breeding colony on Lake Ostrowiec, established over 40 years ago, consisted of over 170 breeding pairs. In the case of Lake Ostrowiec, high pollution with coliform bacteria (including Escherichia coli) was observed. Compared to the control station the significantly higher Most Probable Number (MPN) of coliform bacteria was found in groundwater under the colony. It was found that bacterial counts decreased in the direction of the centre of the water body with the highest numbers noted in the lake samples collected within the colony boundaries. Furthermore, seasonal variations in coliform bacteria were also observed with maximum densities during the breeding season. Similar trends were observed for the roosting colony on Lake Góreckie while for the newly forming colony on Lake Chrzypsko increased density of investigated bacteria was noted only in groundwater.

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