scholarly journals Emergence of the Zoonotic Biliary Trematode Pseudamphistomum truncatum in Grey Seals (Halichoerus grypus) in the Baltic Sea

PLoS ONE ◽  
2016 ◽  
Vol 11 (10) ◽  
pp. e0164782 ◽  
Author(s):  
Aleksija S. Neimanis ◽  
Charlotta Moraeus ◽  
Anders Bergman ◽  
Anders Bignert ◽  
Johan Höglund ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Halichoerus Grypus ◽  
The Baltic Sea ◽  
The Baltic

scholarly journals Life cycle bioenergetics of the gray seal (Halichoerus grypus) in the Baltic Sea: Population response to environmental stress

2020 ◽  
Vol 145 ◽  
pp. 106145 ◽  
Author(s):  
Willian T.A.F. Silva ◽  
Karin C. Harding ◽  
Gonçalo M. Marques ◽  
Britt Marie Bäcklin ◽  
Christian Sonne ◽  
...  
Keyword(s):  
Life Cycle ◽  
Environmental Stress ◽  
Baltic Sea ◽  
Halichoerus Grypus ◽  
The Baltic Sea ◽  
Population Response ◽  
Gray Seal ◽  
The Baltic

scholarly journals Estimation of grey seal (Halichoerus grypus) diet composition in the Baltic Sea

2007 ◽  
Vol 6 ◽  
pp. 177 ◽  
Author(s):  
Karl Lundström ◽  
Olle Hjerne ◽  
Karin Alexandersson ◽  
Olle Karlsson
Keyword(s):  
Baltic Sea ◽  
Diet Composition ◽  
Estimation Method ◽  
Clupea Harengus ◽  
Halichoerus Grypus ◽  
Coregonus Lavaretus ◽  
Correction Factors ◽  
The Baltic Sea ◽  
Hard Part ◽  
The Baltic

We examined the digestive tract contents from 145 grey seals (Halichoerus grypus) collected between 2001 and 2004 in the Baltic Sea. We compensated for biases introduced by erosion of otoliths, both by using additional hard-part structures other than otoliths, and species-specific size and numerical correction factors. In the absence of numerical correction factors based on feeding experiments for some species, we used correction factors based on a relationship between otolith recoveryrate and otolith width. A total of 24 prey taxa were identified but only a few species contributed substantially to the diet. The estimated diet composition was, independently of the prey number estimation method and diet composition estimation model used, dominated by herring (Clupea harengus), both by numbers and biomass. In addition to herring, common whitefish (Coregonus lavaretus) and sprat (Sprattus sprattus) were important prey, but cyprinids (Cyprinidae), eelpout (Zoarces viviparus), flounder (Platichtys flesus) and salmon (Salmo salar) also contributed significantly. Our results indicated dietary differences between grey seals of different age as well as between seals from the northern (Gulf of Bothnia) and the southern (Baltic Proper) Baltic Sea.

scholarly journals Nematode Parasites in Baltic Sea Mammals, Grey Seal (Halichoerus grypus (Fabricius, 1791)) and Harbour Porpoise (Phocoena phocoena (L.)), from the German Coast

2020 ◽  
Author(s):  
Michael Gabel ◽  
Stefan Theisen ◽  
Harry Wilhelm Palm ◽  
Michael Dähne ◽  
Patrick Unger
Keyword(s):  
Baltic Sea ◽  
Parasite Species ◽  
Parasite Fauna ◽  
Eastern Coast ◽  
Halichoerus Grypus ◽  
Phocoena Phocoena ◽  
The Baltic Sea ◽  
Nematode Parasites ◽  
The Baltic ◽  
Anisakid Nematodes

Abstract Purpose Endoparasitic nematodes of six harbour porpoises Phocoena phocoena and four grey seals Halichoerus grypus, stranded at the eastern coast of the Baltic Sea in Germany in winter 2019, were analysed in order to identify nematode parasites and to compare with recent studies from the same area. Methods Endoparasitic nematodes were identified by using both morphological and molecular characters. The successfully obtained sequences of the rDNA marker regions ITS-1, 5.8S, ITS-2 from 29 anisakid and the rDNA marker region ITS-2 of 11 pseudalid nematodes were amplified. Results Analyses revealed the presence of three parasite species, the anisakid nematode Contracaecum osculatum from grey seals and the pseudalid nematodes Pseudalius inflexus and Stenurus minor from the harbour porpoises. Other anisakid nematodes regularly occurring in the Baltic Sea, e.g. Anisakis simplex or Pseudoterranova decipiens, were not found. Conclusions The prevalence of 100% and a severe parasite load in grey seals demonstrated a very high C. osculatum infection of Baltic Sea fish as their regular prey. Prevalence of 33% for parasites in harbour porpoises and minor infection rates, combined with a distinct lack of anisakid nematodes, are typical for the current situation of the porpoise parasite fauna in the Baltic Sea. Invasive parasite species as possible indicators for climate change could not be detected.

scholarly journals Understanding the diet composition of marine mammals: grey seals (Halichoerus grypus) in the Baltic Sea

2010 ◽  
Vol 67 (6) ◽  
pp. 1230-1239 ◽  
Author(s):  
Karl Lundström ◽  
Olle Hjerne ◽  
Sven-Gunnar Lunneryd ◽  
Olle Karlsson
Keyword(s):  
Baltic Sea ◽  
Marine Mammals ◽  
Diet Composition ◽  
Age Groups ◽  
Geographic Region ◽  
Halichoerus Grypus ◽  
The Baltic Sea ◽  
Sampling Condition ◽  
The Baltic ◽  
Sampling Procedures

AbstractLundström, K., Hjerne, O., Lunneryd, S-G., and Karlsson, O. 2010. Understanding the diet composition of marine mammals: grey seals (Halichoerus grypus) in the Baltic Sea. – ICES Journal of Marine Science, 67: 1230–1239. Dietary studies are important in understanding the ecological role of marine mammals and in formulating appropriate management plans in terms of their interactions with fisheries. The validity of such studies has, however, often been compromised by unrepresentative sampling procedures, resulting in false weight being given to external factors seeming to influence diet composition. The bias caused by non-random sampling was examined, using canonical correspondence analysis to assess how the prey species composition in digestive tract samples of Baltic grey seals (Halichoerus grypus) was related to spatial, temporal, and demographic factors and to whether the samples were collected in association with fishing gear or not (“sampling condition”). Geographic region explained the largest fraction of the observed variation, followed by sampling condition, age group, and year. Season and gender were not statistically significant. Segregation of the two age categories “pups” and “juveniles–adults”, and the two geographic categories “Baltic proper” and “Gulf of Bothnia” are proposed to estimate the diet and fish consumption of the Baltic grey seal population as a whole. Atlantic herring was the most commonly recovered prey item in all areas and age groups, followed by European sprat in the south, and common whitefish in the north. Pups had eaten relatively more small non-commercial species than older seals.

THYROID HORMONE STATUS IN GRAY SEAL (HALICHOERUS GRYPUS) PUPS FROM THE BALTIC SEA AND THE ATLANTIC OCEAN IN RELATION TO ORGANOCHLORINE POLLUTANTS

2005 ◽  
Vol 24 (3) ◽  
pp. 610 ◽  
Author(s):  
Eugen Gravningen Sørmo ◽  
Ivar Jüssi ◽  
Mart Jüssi ◽  
Marte Braathen ◽  
Janneche Utne Skaare ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Atlantic Ocean ◽  
Baltic Sea ◽  
Halichoerus Grypus ◽  
The Baltic Sea ◽  
Gray Seal ◽  
Organochlorine Pollutants ◽  
Hormone Status ◽  
The Baltic

Geographic distribution of mitochondrial DNA haplotypes in grey seals (Halichoerus grypus)

1996 ◽  
Vol 74 (10) ◽  
pp. 1787-1796 ◽  
Author(s):  
Radmila Boskovic ◽  
Kit M. Kovacs ◽  
M. O. Hammill ◽  
B. N. White
Keyword(s):  
Mitochondrial Dna ◽  
Baltic Sea ◽  
North Atlantic ◽  
Rflp Analysis ◽  
Genetic Distances ◽  
Halichoerus Grypus ◽  
The Baltic Sea ◽  
Geographic Separation ◽  
Eastern North Atlantic ◽  
The Baltic

Mitochondrial DNA (mtDNA) variation in grey seals (Halichoerus grypus) was estimated by restriction fragment length polymorphism (RFLP) analysis of samples collected from four geographic locations: the Gulf of St. Lawrencn(n = 24), Sable Island, Nova Scotia (n = 20), Norway (n = 16), and the Baltic Sea (n = 20). In total, 18 haplotypes were identified. Nucleotide diversity was estimated to be 0.0039 for the Gulf of St. Lawrence, 0.0035 for Sable Island, 0.0079 for Norway, and 0.0059 for the Baltic Sea. There were no shared haplotypes between the western North Atlantic and eastern North Atlantic groups, and genetic distances between these populations (2.0–2.4%) suggest that they diverged approximately 1.0–1.2 million years ago. Nucleotide divergence between the Baltic Sea and the Norwegian populations was estimated to be 0.7%, suggesting that separation of these two groups took place much more recently, about 0.35 million years ago. The distribution of mtDNA haplotypes among Canadian grey seals suggests little or no geographic separation between animals breeding in the Gulf of St. Lawrence and those breeding on Sable Island. In addition to providing basic information on stock analysis the grey seal mtDNA RFLP analysis should be of value for further studies including polymerase chain reaction and direct sequence analyses.

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