Changes in total mercury, methylmercury, and selenium blood levels during different life history stages of the Baltic grey seal (Halichoerus grypus grypus)

2019 ◽  
Vol 676 ◽  
pp. 268-277 ◽  
Author(s):  
Agnieszka Grajewska ◽  
Lucyna Falkowska ◽  
Dominika Saniewska ◽  
Iwona Pawliczka
Keyword(s):  
Life History ◽  
Total Mercury ◽  
Halichoerus Grypus ◽  
Blood Levels ◽  
Grey Seal ◽  
Life History Stages ◽  
The Baltic

Maternal transfer of phenol derivatives in the Baltic grey seal Halichoerus grypus grypus

2018 ◽  
Vol 242 ◽  
pp. 1642-1651 ◽  
Author(s):  
Iga Nehring ◽  
Lucyna Falkowska ◽  
Marta Staniszewska ◽  
Iwona Pawliczka ◽  
Karina Bodziach
Keyword(s):  
Halichoerus Grypus ◽  
Maternal Transfer ◽  
Grey Seal ◽  
Phenol Derivatives ◽  
The Baltic

Studies on the Life-History of the Ascarid Porrocaecum decipiens in the Bras d'Or Lakes, Nova Scotia, Canada

1960 ◽  
Vol 17 (6) ◽  
pp. 763-774 ◽  
Author(s):  
D. M. Scott ◽  
W. F. Black
Keyword(s):  
Life History ◽  
Nova Scotia ◽  
Intermediate Host ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Phoca Vitulina ◽  
Halichoerus Grypus ◽  
Grey Seal ◽  
Important Food ◽  
History Of

Larvae of the parasitic ascarid (Porrocaecum decipiens) occurred commonly in the musculature and viscera of Atlantic cod (Gadus morhua) in the Bras d'Or Lakes. They were also present in the musculature of nine other species of teleosts and probably also in the viscera of skates (Raja sp.). Most larvae were longer than 20 mm. None was shorter than 10 mm, a fact which suggested the existence of some earlier intermediate host, probably an invertebrate. More than 8,000 mysids, an important food of fishes when they first become infected, were examined for nematodes. Although 110 nematodes were found, only one certainly and four dubiously appeared to be Porrocaecum. The definitive hosts were the harbour seal (Phoca vitulina) and the grey seal (Halichoerus grypus). The distribution of seals coincided with local variations in the incidence of the parasite in cod.

Fur and faeces – Routes of mercury elimination in the Baltic grey seal (Halichoerus grypus grypus)

2020 ◽  
Vol 717 ◽  
pp. 137050 ◽  
Author(s):  
Agnieszka Grajewska ◽  
Lucyna Falkowska ◽  
Dominika Saniewska ◽  
Iwona Pawliczka
Keyword(s):  
Halichoerus Grypus ◽  
Grey Seal ◽  
The Baltic

The breeding and distribution of the grey seal ( Halichoerus grypus Fab.) in the Baltic Sea, with observations on other seals of the area

1972 ◽  
Vol 182 (1066) ◽  
pp. 37-58 ◽  
Keyword(s):  
Baltic Sea ◽  
Halichoerus Grypus ◽  
Grey Seal ◽  
Last Deglaciation ◽  
The Baltic Sea ◽  
Eastern Canada ◽  
The North ◽  
Ice Coverage ◽  
Large Numbers ◽  
The Baltic

The grey seal ( Halichoerus grypus Fab.) is considered to be one of the rarest species of the seals. The area of greatest abundance is centred around the coasts of the British Isles where the species has been established for a considerable period. The Grey Seals Acts of 1914 and 1932 gave protection to the species in British waters during the breeding months of September to December. But this seal also occurs in other countries in the North Atlantic, notably in Eastern Canada, often on ice (figures 12, 13, plate 4), Iceland, the Faroes, Norway, the Kola peninsular and the Baltic Sea. The total population is estimated (Smith 1966) to be ca . 52500. Since the last deglaciation considerable changes have occurred in the Baltic region, but at the present time in this tideless sea – which embraces the Gulfs of Bothnia, Finland and Riga, and in waters of a salinity as low as 3.75 ‰, of an area of 400000 km 2 – the grey seal breeds in March on ice, as does the ringed seal in the same month and also on ice, though the common seal breeds in June on sandbanks or rocks. Within the area is a valuable and productive fishery and an inevitable conflict has for long existed between man and the seals, both predators of economically valuable fish, e. g. herring, cod, eel, salmon and other species, leading to the imposition of bounty payments for seals killed. Over the years very large numbers of grey and ringed seals have been killed, chiefly by fishermen in Sweden and Finland, to obtain bounties from the authorities. Unlike the planned culling and undertaken in some British colonies, the Baltic killings have been made at random and little is known of its effect upon the survival of the species. In the Baltic it is not possible to undertake counts of seals owing to the scattered nature of their breeding and the unpredictability of the winter ice coverage.

Utilizing next-generation sequencing to identify prey DNA in western North Atlantic grey seal Halichoerus grypus diet

2020 ◽  
Vol 655 ◽  
pp. 227-240
Author(s):  
KR Flanders ◽  
ZH Olson ◽  
KA Ono
Keyword(s):  
Next Generation Sequencing ◽  
Feeding Habits ◽  
Atlantic Menhaden ◽  
Halichoerus Grypus ◽  
Frequency Of Occurrence ◽  
Grey Seal ◽  
Next Generation ◽  
Significant Difference ◽  
Generation Sequencing ◽  
Seal Diet

Increasing grey seal Halichoerus grypus abundance in coastal New England is leading to social, political, economic, and ecological controversies. Central to these issues is the foraging ecology and diet composition of the seals. We studied grey seal feeding habits through next-generation sequencing of prey DNA using 16S amplicons from seal scat (n = 74) collected from a breeding colony on Monomoy Island in Massachusetts, USA, and report frequency of occurrence and relative read abundance. We also assigned seal sex to scat samples using a revised PCR assay. In contrast to current understanding of grey seal diet from hard parts and fatty acid analysis, we found no significant difference between male and female diet measured by alpha and beta diversity. Overall, we detected 24 prey groups, 18 of which resolved to species. Sand lance Ammodytes spp. were the most frequently consumed prey group, with a frequency of occurrence (FO) of 97.3%, consistent with previous studies, but Atlantic menhaden Brevoortia tyrannus, the second most frequently consumed species (FO = 60.8%), has not previously been documented in US grey seal diet. Our results suggest that a metabarcoding approach to seal food habits can yield important new ecological insights, but that traditional hard parts analysis does not underestimate consumption of Atlantic cod Gadus morhua (FO = 6.7%, Gadidae spp.) and salmon Salmo salar (FO = 0%), 2 particularly valuable species of concern.

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