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 ◽  
...  
2005 ◽  
Vol 24 (3) ◽  
pp. 610 ◽  
Author(s):  
Eugen Gravningen Sørmo ◽  
Ivar Jüssi ◽  
Mart Jüssi ◽  
Marte Braathen ◽  
Janneche Utne Skaare ◽  
...  

2018 ◽  
Vol 47 (4) ◽  
pp. 398-404 ◽  
Author(s):  
Leszek Rolbiecki ◽  
Joanna N. Izdebska ◽  
Konrad Bidziński ◽  
Martyna Jankowska-Jarek

AbstractParasitic arthropods of marine mammals are relatively poorly understood, with the least amount of data on the occurrence of parasitic arthropods in these hosts. Thus far, only seal lice Echinophthirius horridus (von Olfers, 1816) have been found in the Baltic seals, while there was no information about the presence of parasitic mites in these mammals. The nasopharyngeal mite Halarachne halichoeri (Allman, 1847) has recently been found in the gray seal Halichoerus grypus (Fabricius, 1791), representing a new species (and new genus) for the Polish fauna. Sixty three specimens were found in the nasal cavity and the trachea, including 18 females and 45 males. This is also the first documented record of Halarachnidae in seals of the Baltic Sea. A checklist of parasitic Halarachnidae known from marine mammals is also provided.


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

2010 ◽  
Vol 406 ◽  
pp. 223-238 ◽  
Author(s):  
J Dutz ◽  
V Mohrholz ◽  
JEE van Beusekom

2007 ◽  
Vol 6 ◽  
pp. 177 ◽  
Author(s):  
Karl Lundström ◽  
Olle Hjerne ◽  
Karin Alexandersson ◽  
Olle Karlsson

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.


Author(s):  
Michael Gabel ◽  
Stefan Theisen ◽  
Harry Wilhelm Palm ◽  
Michael Dähne ◽  
Patrick Unger

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.


2019 ◽  
Vol 55 (6) ◽  
pp. 1226-1238 ◽  
Author(s):  
Jacqueline Jerney ◽  
Salla Annika Ahonen ◽  
Päivi Hakanen ◽  
Sanna Suikkanen ◽  
Anke Kremp

2019 ◽  
Vol 62 (1) ◽  
pp. 63-73
Author(s):  
Florian Weinberger ◽  
Sophie Steinhagen ◽  
Dmitry F. Afanasyev ◽  
Rolf Karez

Abstract Combined genetic, morphological and ontogenetic observations show that the circumarctic boreal green algal macrophyte Kornmannia leptoderma has expanded its distribution range into the Baltic Sea, on a German coastal section of 220 km length. The species is also again (or still) established at its former extreme southern distribution limit in the North Sea, the German island of Helgoland, where it has not been detected during the last four decades. Macroscopic visible sporophytes of K. leptoderma are nowadays present in the Baltic Sea and at Helgoland from February to September, while they were in the past only detected from February to May at Helgoland. This capacity for formation of sporophytes in summer correlates with the circumstance that K. leptoderma from the Baltic Sea can complete its life cycle at 15°C while several studies conducted decades ago with material from Helgoland and from Pacific coasts consistently reported an inhibition of the algal gametogenesis at temperatures that exceed 12°C. Possibly K. leptoderma has undergone adaptations that facilitate its spread into warmer environments, unless the Kornmannia present in the Baltic Sea and on Helgoland today represents a newly introduced cryptic species.


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