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.

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.

Nasopharyngeal mites Halarachne halichoeri (Allman, 1847) parasitizing the gray seal Halichoerus grypus (Fabricius, 1791) in the Baltic Sea with notes on other parasitic Halarachnidae associated with marine mammals

2018 ◽  
Vol 47 (4) ◽  
pp. 398-404 ◽  
Author(s):  
Leszek Rolbiecki ◽  
Joanna N. Izdebska ◽  
Konrad Bidziński ◽  
Martyna Jankowska-Jarek
Keyword(s):  
New Species ◽  
Baltic Sea ◽  
Marine Mammals ◽  
New Genus ◽  
Halichoerus Grypus ◽  
The Baltic Sea ◽  
Gray Seal ◽  
The Baltic ◽  
Parasitic Mites ◽  
A New Species

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.

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

Alimentary exposure and elimination routes of rare earth elements (REE) in marine mammals from the Baltic Sea and Antarctic coast

2021 ◽  
Vol 754 ◽  
pp. 141947
Author(s):  
Andrzej R. Reindl ◽  
Dominika Saniewska ◽  
Agnieszka Grajewska ◽  
Lucyna Falkowska ◽  
Michał Saniewski
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Baltic Sea ◽  
Marine Mammals ◽  
The Baltic Sea ◽  
The Baltic

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.

THE ROLE OF TOXICOSIS IN THE ADAPTION OF ECOSYSTEMS FOR ANTHROPOGENIC POLLUTION OF THE ENVIRONMENT (AT THE EXAM-PLE OF TOXICOSIS OF WATER ANI-MALS)

2020 ◽  
Vol 2 ◽  
pp. 78-83
Author(s):  
A.V. Makrushin ◽  
◽  
A. S. Vasiliev ◽  
N. M. Arshanitsa ◽  
O. A. Lyashenko ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Fish Larvae ◽  
Age Groups ◽  
Komi Republic ◽  
Lake Ladoga ◽  
Leningrad Region ◽  
The Baltic Sea ◽  
Volga River ◽  
The Baltic ◽  
The Impact

In the past geological eras in the bio-sphere, species extinction was accompanied by speciation. Ecosystems adapted to a greater or lesser extent to coexist with a species whose activity had become a plane-tary factor and had a global impact on bio-spheric processes. One of it is the massive pollution of the main components of the biosphere - geobiosphere, hydrobooster and air. Its consequence is the development in living organisms of various pathological processes associated with the impact of tox-icants-toxicoses. The work was carried out in various re-gions of the USSR and Russia on reservoirs of various types and different objects of aquaculture. Various species and age groups of fish were studied. They were caught with trawls, nets, lifts, and sport fishing gear. Fish larvae were caught with a plankton net. A pathoanatomic method was used to assess the condition of fish. In some cases, histo-logical methods were used. Clams of the family Unionidae were surveyed in 1990-2011. They were collected by dredging in the reservoirs of the Volga, in the lake Ilmen, in the red sea of the Ka-relian isthmus of the Leningrad region and in the Gulf of Finland of the Baltic sea. The liver of 399 individuals was examined us-ing histological methods. Also Perlovitz. Unio pictorum, 474 copies of U. tumidus and 298 copies. the mussels Anodonta sp. Branched crustaceans were examined in 1989-2016. They were collected in a plank-ton grid in the reservoirs of the Volga, in the Nyvchimsky reservoir (the basin of the Volga river). Vychegda Komi Republic, in the Finnish and Kursk bays of the Baltic sea, in lake Ladoga, in the lake of Sevan (Armenia) and in lakes of the Karelian isth-mus of Leningrad region, in the mountain lakes of West Sayan (Krasnoyarsk region), the lakes in Darwin reserve (Vologda re-gion) and in the pools of Garbacki lakes Bolshezemelskaya tundra (Vorkuta district, Komi Republic). Fixation in 4% formalin by Rachkov method was examined in Bo-gorov's cell under the MBS-9 microscope.

Diet composition of herring (Clupea harengus L.) and cod (Gadus morhua L.) in the southern Baltic Sea in 2007 and 2008

2011 ◽  
Vol 40 (4) ◽  
Author(s):  
Diana Dziaduch
Keyword(s):  
Baltic Sea ◽  
Diet Composition ◽  
Gadus Morhua ◽  
Clupea Harengus ◽  
The Baltic Sea ◽  
Commercial Fish ◽  
Southern Baltic Sea ◽  
Starting Point ◽  
Southern Baltic ◽  
The Baltic

AbstractDiet composition of two commercial fish species, herring and cod, were studied in some regions (mainly Gda’nsk and Bornholm Basins, and the Polish coast) of the southern Baltic Sea in 2007 and 2008. Herring is the dominant zooplanktivorous species in the ecosystem of the Baltic Sea, but apart from mesoplanktonic organisms it also eats macroplanktonic and benthic species in considerable amount. The diet of cod consists of fish and crustaceans from pelagic, hyperbenthic and benthic habitats. The feeding preferences of fish indirectly reflect changes in the whole food chain in the Baltic Sea. This research focuses specifically on these invertebrate species, which are eliminated from the environment by most of the ichthyofauna of this region. The aim of this research is to examine the role of invertebrate organisms belonging to Crustacea in the diet of herring and adult cod to supply updated results about feeding of these fish as little data have been collected since the 1990s. The present study is a preliminary survey and results can not be considered conclusive. The restricted numbers of analyzed stomachs of fish and selected seasons of the year addressed in this paper are a starting point for further studies with a larger scope. In this study, 20 to 90% of herring had empty stomachs. Mesozooplankton dominated the diets of small and large herring. Mysidacea, which were historically important prey for herring, are now scarce and have been replaced by planktonic Amphipoda. In the case of cod, consumption of Mysidacea has never been as low as in this study. As for other invertebrate prey, the benthic isopod Saduria and Crangon shrimp achieved the highest amount by number and weight. These results show distinct changes in diet when compared to previous investigations and require verification at a larger spatial scale.

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