Four dead Phalacrocorax carbo sinensis specimens from Southern Italy coasts were examined for Contracaecum sp. detection. 181 Contracaecum sp. larvae and adults were found in the viscera of all the ...P. carbo sinensis examined. The PCR-RFLP analysis showed the presence of Contracaecum rudolphii A and B. A co-infestation of C. rudolphii A and B was found in P. carbo sinensis from Leporano Bay. This study provides a first report of the presence of Contracaecum sp. in P. carbo sinensis from Southern Italy. In this study, four dead great cormorant Phalacrocorax carbo sinensis (Blumenbach, 1978) specimens, collected from the coasts and lakes of Southern Italy, were examined by necropsy for the detection of Contraceacum sp. The adults and larvae found were subjected to morphological analysis and molecular identification by PCR-RFLP. A total of 181 Contracaecum specimens were detected in all of the four great cormorants examined (prevalence = 100%), showing an intensity of infestation between nine and ninety-two. A co-infestation by adult and larval forms of Contracaecum rudolphii was found only in one of the great cormorants examined. Following molecular investigations, 48 specimens of C. rudolphii A and 38 specimens of C. rudolphii B were detected, revealing co-infestation solely for the great cormorant from Leporano Bay (Southern Italy). Our results showed an opposite ratio between C. rudolphii A and C. rudolphii B in Pantelleria and in Salso Lake (Southern Italy) compared to what was reported in the literature, probably due to migratory stopovers and the ecology of the infested fish species, confirming the role of Contracaecum nematodes as ecological tags of their hosts.
The guanay cormorant (Leucocarbo bougainvilliorum) and red-legged cormorant (Poikilocarbo gaimardi) are known for their prolific nest-building behavior, utilizing a diverse array of materials, ...including anthropogenic debris, thereby serving as valuable indicators of ocean plastic pollution. To elucidate inter-specific variations in nest plastic occurrence between these two cormorant species, we conducted a comprehensive examination of nests at 12 colonies along the Peruvian coast in 2018–2019. Our findings revealed a significantly higher occurrence of plastic in red-legged cormorant nests (mean 50 ± 27 %, N = 100 nests in 7 colonies) compared to guanay cormorant nests (mean 10 ± 20 %, 3497 nests in 8 colonies). Furthermore, the prevalence of plastic waste varied across colonies within both species. Off-white/clear plastic bags were the predominant color and type of debris found in both cormorant nests. This study is a baseline of plastic marine pollution occurrence along the Peruvian coast.
•Plastic debris was found in 10 % and in 50 % of guanay and red-legged cormorant nests, respectively.•The maximum occurrence of plastic debris in the nests varied from 59 % in guanay to 86 % in red-legged cormorants.•The most common type of plastic found in the nests were bags, primarily in off/white/clear, black, and blue/purple colors.•Plastics accounted for a small fraction of the total material weight in guanay cormorant nests (0.04 % - 2.66 %).
This study aims to provide consistent information to explain the steady declining trend in the number of breeding pairs of Antarctic shag Phalacrocorax bransfieldensis in two colonies on Nelson ...Island, South Shetland Islands, southern Atlantic sector of Antarctica, which was observed during the 1990s up to the mid 2000s over an overall monitoring period of over two decades. It addresses correspondence between long-term population trends of inshore demersal fish and inshore-feeding Antarctic shags of this area, where an intensive commercial fishery for shag prey once operated. The analysis also includes comparable information on diet (by examination of regurgitated pellets), foraging patterns, and breeding output of shags from the Danco Coast, western Antarctic Peninsula, an area where no commercial finfish fishery has ever existed. Integral study of these parameters there showed that, in Antarctic shags, low breeding success and high foraging effort might imply low recruitment and high adult mortality, respectively, with both factors adversely affecting the population trends of this bird. In line with these premises, the declining trend observed in shag colonies on the South Shetland Islands appears to have been influenced by the concomitant decrease in abundance of two of their main prey, the nototheniids Notothenia rossii and Gobionotothen gibberifrons, due to intensive industrial fishing in the area in the late 1970s. In comparison, no such pattern occurred for the Danco Coast colonies.
Eggshell thickness can be an indicator of environmental pollution in wild birds and shell quality in wild and domestic birds, but it is difficult to measure calcite eggshell thickness due to the ...presence of the adherent outer eggshell membrane. Eggshells of 13 waterbird species were divided in half longitudinally and the outer membrane was removed from one of the halves. Subsequently, we measured eggshell thickness, both with and without the outer eggshell membrane, using a Hall-effect thickness gauge to the nearest 0.001 mm along the equator of each eggshell half. Outer eggshell membrane thicknesses ranged from 0.014 to 0.073 mm. Caspian Tern (Hydroprogne caspia) and California Gull (Larus californiens) had the thickest eggshell membranes (0.056 and 0.073 mm, respectively), and Green Heron (Butorides virescens) and Killdeer (Charadrius vociferus) had the thinnest membranes (0.014 and 0.022 mm, respectively). The eggshell membrane, as a percent of the total eggshell and membrane thickness, varied among the 13 species and ranged among species from 7.9% to 20.6%. The outer membrane comprised a greater percent of the total eggshell and membrane thickness for Black Skimmer (19.3%; Rynchops niger), California Gull (20.5%), and Forster's Tern (20.6%; Sterna forsteri) than for Green Heron (7.9%), Double-crested Cormorant (10.4%; Phalacrocorax auritus), and Western Grebe (10.6%; Aechmophorus occidentalis). Within species, the outer membrane thickness was not correlated with egg morphometries but, for a subset of species, there was some indication that the calcite eggshell thickness decreases with embryo development (age). We discuss several reasons for conducting future eggshell thickness measurements without removing the membrane. Received 27 February 2023. Accepted 31 December 2023.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The great cormorant
Phalacrocorax carbo
(Linnaeus, 1758) can create significant conflicts with fisheries as a result of removing significant fish biomass. This is exacerbated by recent population ...increase in most of Europe. This study uses long-term census, climate, and environmental data to explore the wintering dynamics and strategies of the species. In Turkey, the total overwintering population, population density, and distribution of cormorants have increased significantly. Correlations with different climatic accounted for 20% to 56% of the variation in the total number of overwintering cormorants. The total number of cormorants overwintering was positively affected by warmer weather conditions in autumn and negatively by increased snow cover in winter. The Principal component analysis identified attraction (At) and avoidance (Av) factors, a two-component solution involving 12 climate variables for choosing the wintering sites of cormorants, that explained 84.3% of the total variance in total number of overwintering cormorants. Linear regression using the scores of the At/Av climate factors predicted 59.0% of the total number of overwintering birds. Our study also demonstrates that long-term census data with both resident and winter migrant populations during the winter can be used to estimate the resident population size of the species.
Abstract
The aptly named microcormorants (currently placed in the genus Microcarbo) form a morphologically diminutive and distinct clade sister to all other living cormorants and shags. However, the ...relationships within Microcarbo are largely speculative. Sequence data resolve these relationships unambiguously, with our phylogeny suggesting that the microcormorants separated from the other cormorants ~16 Mya and showing that the two African species the reed (or long-tailed) cormorant, Microcarbo africanus, and the crowned cormorant, Microcarbo coronatus are closely related sister taxa, forming a clade that diverged from the other microcormorants ~12 Mya. The deep split between the African microcormorants and the others is considerably older than many well-recognized generic splits within the cormorants (e.g. Leucocarbo and Phalacrocorax). Thus, we suggest that the African microcormorants warrant their own genus, and we erect Afrocarbo, with type species Pelecanus africanus. Within the reduced Microcarbo, we estimate that the little pied cormorant (Microcarbo melanoleucos of Australasia) separated from the sister pair of the Javanese and pygmy cormorants (respectively, Microcarbo niger from south/southeast Asia and Microcarbo pygmaeus from Europe) ~9 Mya and that the latter two species split ~2 Mya. Given the age of these splits, the microcormorants appear to represent another example of morphological conservatism in the Suliformes.
Contracaecum rudolphii
(s. l.) is a complex of sibling species of anisakid nematodes having the fish-eating birds belonging to the Family Phalacrocoracidae as final hosts. The great cormorant
...Phalacrocorax carbo sinensis
is parasitized by
C. rudolphii
A and
C. rudolphii
B. Adults and L4 specimens of
C. rudolphii
(s. l.) (
N
= 3282) were collected in cormorants from brackish and freshwater ecosystems of Central Italy. Third-stage larvae of
Contracaecum
(
N
= 882) were obtained from the fish species
Dicentrarchus labrax
,
Anguilla anguilla
,
Aphanius fasciatus
,
Atherina boyeri
,
Leuciscus cephalus
,
Barbus barbus
, and
Carassius carassius
captured in the same geographical areas of cormorants’ standings.
Contracaecum rudolphii
A and
C. rudolphii
B were identified by a multilocus genetic approach: allozymes, sequences analysis of the mtDNA
cox2
, and ITS region of rDNA gene loci. Differential distribution of the two parasite species was observed in different aquatic environments.
Contracaecum rudolphii
B outnumbered
C. rudolphii
A in wintering cormorants from freshwater ecosystems; the opposite trend was found in cormorants from brackish water. Analogously,
C. rudolphii
A larvae were more prevalent in brackish water fish, while
C. rudolphii
B larvae were found infecting only freshwater fish. The findings seem to confirm that
C. rudolphii
A and
C. rudolphii
B would have a life-cycle adapted to brackish and freshwater environments, respectively. A differential feeding behavior of wintering cormorants, the ecology of the infected fish species, and abiotic factors related to early stages of the parasites are supposed to maintain the distinctiveness of the two parasite species’ life cycles in the two different aquatic ecosystems.
Bis(4-chlorophenyl) sulfone (BCPS, CAS No. 80-07-9) is used as monomer for the production of several groups of polymers like polysulphones and polyethersulphones. Residual amounts of monomer remain ...in the polymer matrix and might migrate out from the polymer matrix. In the present study, freshwater fish and fish-eating birds were examined. Following fish species (top predators) were collected at two Austrian locations: Sander lucioperca, Silurus glanis, and Lota lota. Whole fish samples were analysed for BCPS. Levels in freshwater fish ranged between 1.3 and 9.3 ng/g fat. In addition, breast muscle and liver samples from six cormorants (Phalacrocorax carbo sinensis) were investigated. BCPS levels in cormorants breast muscle were in the range of 4.3–40 ng/g fat (mean: 16.3 ng/g fat, n = 6) and 28–86 ng/g fat (mean: 53.5 ng/g fat, n = 6) in the liver samples. BCPS concentration in liver was 3.3-fold higher than in muscle tissue. One of the cormorants had ingested fish with a BCPS level of 5.5 ng/g fat; BCPS levels in the cormorant were 23 ng/g fat (breast muscle) and 28 ng/g fat (liver), suggesting biomagnification values (BMF) of 4.2 (fish/breast muscle) and 5.1 (fish/liver), respectively. A BMF value higher than 1 can be considered as an indication for very high biomagnification. Comparing the BCPS concentrations of cormorants’ breast muscle from 2019 (mean: 16 ng/g fat) to the concentrations from 2001 to 2005 (mean: 8.9 ng/g fat), indicates that BCPS levels might be increasing in Europe.
•BCPS was detected in all tested cormorant and freshwater fish samples.•Comparison between BCPS levels in fish and cormorants indicates biomagnification.•Liver seems to be the target organ of BCPS in cormorants.•Recommendations to measure BCPS in aquatic environments and several bird species including their prey from various regions.
Since the European population of great cormorants (
Phalacrocorax carbo sinensis
) rapidly increased 30 years ago, Denmark has been one of the core breeding areas for this colonial water bird. ...Following a 10-year period with stable breeding numbers in Denmark, the population of great cormorants decreased. At the same time, a combination of cold winters and low availability of coastal prey fish apparently triggered birds to seek new foraging areas. Thus, cormorants began to appear in rivers and streams coinciding with an observed massive decline of fish, mainly brown trout (
Salmo trutta
) and grayling (
Thymallus thymallus
). In this paper, we present the results from studies using radio-telemetry, PIT-tagging, and traditional fish surveys to estimate the impact of predation in Danish lowland rivers. Recovery of PIT-tags revealed that an estimated 30% of wild trout and 72% of wild grayling tagged in a small river were eaten by cormorants. In another medium-sized river, 79% of radio-tagged adult grayling were removed, presumably by cormorants during winter. Thus, predation from cormorants appears to be at a level that explains the observed collapse of grayling and brown trout populations in many Danish streams.
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