scholarly journals Fish consumption of the great cormorant in the area of Hortobágy Fish Farm

2014 ◽  
pp. 81-84
Author(s):  
Norbert Tóth ◽  
Péter Gyüre ◽  
Lajos Juhász
Keyword(s):  
Fish Species ◽  
Bird Species ◽  
Fish Farm ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Fish Stocks ◽  
Nature Preservation ◽  
Near Future ◽  
The Given ◽  
Intensive System

The cormorant (Phalacrocorax carbo) is a bird species that nests sporadically but in colonies, besides larger fishponds and rivers in Hungary. The number of its individuals has been increasing during the last two decades. The species eats solely fish, therefore it can cause serious depredation of the fish stocks in fishponds of intensive system and after the freezing of the ponds, in larger rivers, which are not yet frozen. The aim of our research is to reveal the damages the birds can cause on the studied areas and the extent of the losses the Hortobágy Fish Farm Co. has to realize. Our studies were carried out between April 2012 and November 2013. During cleaning, the investigation of the crop contents of the birds and their biometric studies were conducted. The results revealed the diverse nutrition base of the species. In the samples, we have determined 300 identified fish individuals; in 289 cases, the exact fish species were determined, too. Although statistical differences were found between the given pond unit and the consuming of the corresponding fish species (P=0.05% beside), this cannot be considered as absolutely certain. Our investigation is of considerable significance in terms of nature preservation and not least, it has substantial financial concerns too. Under the ever harder fish production conditions, the presence and thus the permanent nutrition of the bird affect the fishermen. In favour of the maintaining of the natural ecological balance and the income of the fishers, the elaboration of adequate protective and efficient preventive processes will be necessary in the near future.

scholarly journals Recent data about the fish consumption of great Cormorant in the area of Hortobágy Fish Farm Co

2015 ◽  
pp. 75-80
Author(s):  
Norbert Tóth ◽  
Péter Gyüre ◽  
Péter Juhász ◽  
Lajos Juhász
Keyword(s):  
Fish Species ◽  
Bird Species ◽  
Fish Farm ◽  
Great Cormorant ◽  
Adult Males ◽  
Phalacrocorax Carbo ◽  
Fish Stocks ◽  
Significant Difference ◽  
Preventive Methods ◽  
Near Future

The cormorant (Phalacrocorax carbo) is a bird species that nests sporadically but in colonies, besides larger fishponds and rivers in Hungary. The number of its individuals has been increasing during the last two decades. The species eats solely fish, therefore it can cause serious depredation of the fish stocks in fishponds of intensive system and after the freezing of the ponds, in larger rivers, which are not yet frozen. The aim of our research was to reveal the damages the birds can cause on the studied areas and the extent of the losses the Hortobágy Fish Farm Co. has to realize. Our studies were carried out between April 2012 and November 2014. During cleaning, the investigation of the craw contents of the birds and their biometric studies were conducted. The results revealed the diverse food base of the species. In the samples, we have determined 379 fish individuals; in 368 cases, the exact fish species were determined, too. Significant differences were found between the consumed fish species rations of the units (P=0.05% beside). We have also found significant difference in the fish consumptions of adult males and females. Under the ever harder fish production conditions, the presence and thus the permanent predation of the birds affect the fishermen. In favour of maintaining ecological balance as well as to hold the income of the fish farmers, elaboration of adequate protective and preventive methods will be needed in near future.

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.

scholarly journals Some interactions between coastal fisheries and sea birds in the Aegean Sea

2020 ◽  
Vol 37 (2) ◽  
pp. 139-147
Author(s):  
Tevfik CEYHAN ◽  
Okan AKYOL
Keyword(s):  
Bird Species ◽  
Aegean Sea ◽  
Small Scale ◽  
Great Cormorant ◽  
Fish Farms ◽  
Phalacrocorax Carbo ◽  
Sea Birds ◽  
The Difference ◽  
Sea Cage ◽  
Cage Fish

In this study, it is aimed to determine the some interactions between various fishery types and seabirds, results of this interaction and sea bird species that have been interacting due to secondary attraction factors. A total of 80 fishermen, working in fish farms, small scale fishery (SSF) and lagoons located in Izmir, Aydın and Muğla were face-to-face interviewed between September 2016 and December 2018. The great cormorant (Phalacrocorax carbo), yellow-legged gull (Larus michahellis), great white egret (Ardea alba), some yelkouan shearwater (Puffinus yelkouan) and great white pelican (Pelecanus onocrotalus) are the bird species that have an interaction with coastal fishermen and sea-cage fish farms. 82% of employees in sea-cage fish farms mentioned that they have an interaction with sea birds in winter, besides %50 of SSF have an interaction with sea birds in summer. The difference between interaction rate according to seasons has been found as statistically significant (p<0.05). 33% of employees in fish farms expressed that they see sea birds during the day. This ratio is 21.7% and 15% for SSF and fishermen in lagoon, respectively. Furthermore, 8.3% of fishermen in lagoon, 11% of employees in fish farms and SSF mentioned that they have an interaction with seabirds especially in the morning time.

scholarly journals Identification of Bird Species Used to Make a Viking Age Feather Pillow

ARCTIC ◽  
2016 ◽  
Vol 69 (1) ◽  
pp. 29 ◽  
Author(s):  
Carla J. Dove ◽  
Stephen Wickler
Keyword(s):  
Iron Age ◽  
Bird Species ◽  
Microscopic Analysis ◽  
The Body ◽  
Great Cormorant ◽  
Viking Age ◽  
Phalacrocorax Carbo ◽  
Late Iron Age ◽  
Wool Textile ◽  
Level Identification

A grave containing the remains of a wooden boat was discovered in 1934 under a low mound in a bog at Øksnes in the Vesterålen islands of northern Norway. The boat grave dates to the 10th century in the Viking Age, and grave goods placed in the boat include an iron axe, a cowhide in which the body was wrapped, and pillow remains consisting of feather stuffing and a wool textile cover. A microscopic analysis of the feathers from a subsample of the pillow fill identified three avian orders: Anseriformes (eider); Suliformes (cormorant), and Charadriiformes (unspecified gull). It was possible to make one species-level identification of Great Cormorant (<em>Phalacrocorax carbo</em>) and to narrow the gull types to the “white-headed” gull group. The sample was composed of a nearly equal mix of downy and pennaceous feather types. Downy feathers from gulls (Laridae) composed the majority of the material in this sample. While it is reported that feathers and down (assumed to be eider) were used in the Late Iron Age, this is the first successful attempt to identify bird species used in these materials and suggests that avian species identifications should be explored in other such burial items to enhance our understanding of human-wildlife interactions throughout Norse history.

scholarly journals Differences in the diet of breeding Cormorants Phalacrocorax carbo sinensis in an inland colony: the effect of years, breeding stages and locations within the colony

2018 ◽  
Vol 18 (4) ◽  
pp. 149-156
Author(s):  
Simone Buttu ◽  
Giulia Atzori ◽  
Francesco Palmas ◽  
Robert Gwiazda
Keyword(s):  
Fish Species ◽  
Fish Assemblages ◽  
Perca Fluviatilis ◽  
Rutilus Rutilus ◽  
Colony Development ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Phalacrocorax Carbo Sinensis ◽  
Different Seasons ◽  
The Impact

AbstractA study of the diet of the Great Cormorant Phalacrocorax carbo sinensis (fish species and size) in (1) different seasons (years), (2) breeding stages (incubation and chick rearing), and (3) breeding areas (center and edge) in the colony in the Dzierżno-Duże Reservoir (southern Poland) was carried out. Overall, 147 pellets of the Great Cormorant were analysed. The low values of the indexes of Levin (Bi) and Shannon (H’) showed a limited trophic spectrum in the diet of the Great Cormorant. Roach (Rutilus rutilus) with a percentage index of relative importance (%IRI) of 62.89, perch (Perca fluviatilis) (%IRI = 22.63) and carp (Cyprinus carpio) (%IRI = 10.43), were the most common prey. Evident changes in the diet between 2003 and 2014, with less roach and more perch and ruffe in 2014 were found. They could be probably related to changes in the fish community. Differences in the food of cormorants between breeding stages reflected dietary requirements of the chicks. During the breeding season younger chicks require feeding with smaller fish than older chicks. The proportion of fish species found in the cormorant diet differed between the edge and the centre of the colony. We concluded that the impact of Great Cormorants on native fish assemblages may be dependent on the location within the colony, development state of the chicks and season, not just fish availability.

scholarly journals Seasonal variations in numbers of great cormorant (Phalacrocorax carbo) on the Kolut fish farm (nw Serbia)

2006 ◽  
Vol 58 (2) ◽  
pp. 83-86
Author(s):  
M. Tucakov
Keyword(s):  
Seasonal Variations ◽  
Spring Migration ◽  
Fish Farm ◽  
Predation Pressure ◽  
Autumn Migration ◽  
Breeding Period ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Breeding Colony ◽  
Long Time

Seasonal variations in numbers of great cormorant were studied between 1998 and 2004 on ponds of the Kolut fish farm (NW Serbia). Its presence is not detected only during winter. Spring migration culminates in early March. Autumn migration lasts for a long time, with the peak in early October. During the breeding period, the average number never exceeded 20 individuals, probably coming from the nearest breeding colony (35 km from the fishponds). Predation pressure was very low throughout the year, except in October (2.44 individuals/10 ha of ponds). No reason for great cormorant depletion exists in the breeding period, when the predation pressure was below 0.5 birds/10 ha.

Identification and Transformation of Terminal Morphemes in Medical English

1969 ◽  
Vol 8 (02) ◽  
pp. 84-90 ◽  
Author(s):  
A. W. Pratt ◽  
M. Pacak
Keyword(s):  
Word Form ◽  
Subsequent Transformation ◽  
Part Of Speech ◽  
Morphological Segmentation ◽  
Medical English ◽  
Nominal Form ◽  
Admissible Path ◽  
Near Future ◽  
The Given ◽  
Admissible Sequences

The system for the identification and subsequent transformation of terminal morphemes in medical English is a part of the information system for processing pathology data which was developed at the National Institutes of Health.The recognition and transformation of terminal morphemes is restricted to classes of adjectivals including the -ING and -ED forms, nominals and homographic adjective/noun forms.The adjective-to-noun and noun-to-noun transforms consist basically of a set of substitutions of adjectival and certain nominal suffixes by a set of suffixes which indicate the corresponding nominal form(s).The adjectival/nominal suffix has a polymorphosyntactic transformational function if it has the property of being transformed into more than one nominalizing suffix (e.g., the adjectival suffix -IC can be substituted by a set of nominalizing suffixes -Ø, -A, -E, -Y, -IS, -IA, -ICS): the adjectival suffix has a monomorphosyntactic transformational property if there is only one admissible transform (e.g., -CIC → -X).The morphological segmentation and the subsequent transformations are based on the following principles:a. The word form is segmented according to the principle of »double consonant cut,« i.e., terminal characters following the last set of double consonants are analyzed and treated as a potential suffix. For practical purposes only such terminal suffixes of a maximum length of four have been analyzed.b. The principle that the largest segment of a word form common to both adjective and noun or to both noun stems is retained as a word base for transformational operations, and the non-identical segment is considered to be a »suffix.«The backward right-to-left character search is initiated by the identification of the terminal grapheme of the given word form and is extended to certain admissible sequences of immediately preceding graphemes.The nodes which represent fixed sequences of graphemes are labeled according to their recognition and/or transformation properties.The tree nodes are divided into two groups:a. productive or activatedb. non-productive or non-activatedThe productive (activated) nodes are sequences of sets of graphemes which possess certain properties, such as the indication about part-of-speech class membership, the transformation properties, or both. The non-productive (non-activated) nodes have the function of connectors, i.e., they specify the admissible path to the productive nodes.The computer program for the identification and transformation of the terminal morphemes is open-ended and is already operational. It will be extended to other sub-fields of medicine in the near future.

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