Harp seal (Phoca groenlandica) invasions in Norwegian coastal waters: age composition and feeding habits

Data were collected from harp seal (Phoca groenlandica) and hooded seal (Cystophora cristata) pups belonging to the Greenland Sea (or "West Ice") stocks in 1995-1997. Pups of both species were observed to feed independently shortly after weaning, and their first food was almost exclusively crustaceans. Parathemisto sp., particularly P. libellula, dominated the diet of both the harp and the hooded seal pups, but the diet also contained sympagic amphipods of the genus Gammarus. Krill (Thysanoessa sp.) was of minor importance as food for seal pups in 1995, but occurred more frequentlyin the diet of both species in 1996 and 1997. Considerable niche overlap may suggest some interspecific competition between harp and hooded seal pups in the West Ice.

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Feeding Habits of Juvenile and Young Yellow Tail Seriola quinqueradiata in Coastal Waters of the South Sea, Korea

Korean Journal of Fisheries and Aquatic Sciences ◽

10.5657/kfas.2016.0635 ◽

2016 ◽

Vol 49 (5) ◽

pp. 635-641

Author(s):

Jae-Mook Jeong ◽

Kang-Seok Hwang ◽

Se-hyun Song ◽

Hee-yong Kim ◽

Jeong-Ho Park ◽

...

Keyword(s):

Coastal Waters ◽

Feeding Habits ◽

The South ◽

Seriola Quinqueradiata ◽

South Sea

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Validation of Age Estimation in the Harp Seal, Phoca groenlandica, Using Dentinal Annuli

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-165 ◽

1983 ◽

Vol 40 (9) ◽

pp. 1430-1441 ◽

Cited By ~ 65

Author(s):

W. D. Bowen ◽

D. E. Sergeant ◽

T. Øritsland

Keyword(s):

Outer Layer ◽

Age Estimation ◽

Transverse Section ◽

Age Determination ◽

Middle Layer ◽

Harp Seal ◽

Growth Layer ◽

Phoca Groenlandica ◽

Incremental Growth ◽

Absolute Age

We investigated the validity and accuracy of age estimation in harp seals, Phoca groenlandica, using a sample of 155 known-age teeth from seals age 3 mo to 10 yr. Under transmitted light, transverse sections of harp seal canine teeth showed distinct incremental growth layers (IGLs) in the dentine. The first growth-layer group (GLG), representing Ist-year growth, consists of two IGLs: an outer layer of opaque dentine, bounded by the neonatal line, and an inner layer of translucent dentine. Subsequent GLGs, each representing 1 yr of growth, generally consist of three IGLs: an outer layer of interglobular dentine deposited during the annual molt in April, a middle layer of opaque dentine formed during the northward spring migration (May–June), and an inner layer of translucent dentine formed from July to March. We show that dentinal GLGs can be used to estimate the absolute age of harp seals. The accuracy of the method decreases with age. Only 72.4% of estimates of 0-group seals were correct using only transverse sections. These errors were virtually eliminated (99.0% correct age determination) when the tooth root was examined. Based on a single examination of a transverse section, the probabilities of correctly estimating age are 0.983, 0.889, 0.817, and 0.553 at ages 1, 2, 3, and 4 + yr, respectively, when clearly inaccurate tag-tooth associations are omitted. The respective probabilities are only slightly higher when age is based on the average of five blind readings, being 1.0, 0.889, 0.833, and 0.625. Beyond age 3 yr, existing data are insufficient to estimate reliably the accuracy of age determined by counting GLGs.

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Effect of Sex, Age and Carcass Cut on Composition of Harp Seal (Phoca groenlandica) Meat

Canadian Institute of Food Science and Technology Journal ◽

10.1016/s0315-5463(82)72543-x ◽

1982 ◽

Vol 15 (3) ◽

pp. 229-232 ◽

Cited By ~ 7

Author(s):

J.R. Botta ◽

E. Arsenault ◽

H.A. Ryan

Keyword(s):

Harp Seal ◽

Phoca Groenlandica

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The life histories and population dynamics of monogenean gill parasites of Trachurus trachurus (L.)

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s002531540005428x ◽

1962 ◽

Vol 42 (3) ◽

pp. 587-600 ◽

Cited By ~ 24

Author(s):

J. Llewellyn

Keyword(s):

Coastal Waters ◽

Life Histories ◽

Feeding Habits ◽

Limiting Factor ◽

Trachurus Trachurus ◽

Free Living ◽

Sea Bottom ◽

Second Year ◽

Post Spawning ◽

Gill Parasites

Gastrocotyle trachuri and Pseudaxine trachuri infect young Trachurus trachurus at Plymouth as soon as the 3- or 4-month-old adolescent fishes descend to the sea bottom in October. The parasites normally mature in 3 or 4 months, but, exceptionally, in about 1 month, and the life-span is normally no longer than 1 year. Trachurus specimens at the beginning of their second year pick up a largely new infection of parasites.G. trachuri and P. trachuri are much less frequent on 2- and 3-year-old specimens of Trachurus and probably occur only very rarely on still older fishes, the limiting factor being not an age-immunity but a post-spawning migration of the host from the concentration of free-living infective stages of the parasites in coastal waters.The parasites have adapted themselves to a seasonal change in the feeding habits of Trachurus by ceasing to produce larvae in anticipation of the summer disappearance of scad from the sea bottom in pursuit of pelagic food-organisms.

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Distribution of Mercury in the Sediments and Fishes of the Lagoon of Aveiro, Portugal

Water Science & Technology ◽

10.2166/wst.1986.0189 ◽

1986 ◽

Vol 18 (4-5) ◽

pp. 141-148 ◽

Cited By ~ 39

Author(s):

M. F. Lucas ◽

M. T. Caldeira ◽

A. Hall ◽

A. C. Duarte ◽

C. Lima

Keyword(s):

Coastal Waters ◽

Total Mercury ◽

Feeding Habits ◽

Sediment Concentration ◽

Point Sources ◽

The Other ◽

Ecological Niches ◽

Ongoing Work ◽

Superficial Sediments ◽

Significant Point

Dry and wet sieving were compared on their suitability for the size fractionation of bottom sediment samples, collected from a brackish water, coastal lagoon, prior to flameless atomic absorption analysis of the sediment concentration of total mercury. The work aimed at identifying the most important point sources of mercury to the lagoon waters and at assessing the distribution, throughout the ecosystem, of the mercury discharged. The results reported in this paper refer to the lagoon sediments and fishes. Ongoing work is extending the survey to the other inland ecological niches and to the coastal waters and sediments. A chlor-alkali plant proved to be the most important source of mercury but its contribution has not yet been disentangled from those originating at a pyrite roasting facility and a PVC factory operating in the same industrial park. Sewage discharges from the bankside communities are the other significant point sources of Hg. Concentrations of Hg in the superficial sediments ranged from 850 mgkg−1, near the chlor-alkali sewer outlet, to 0.05 mgkg−1 in the intertidal sands of the coastal beaches. Sewage-affected sediments have concentrations of Hg in the range of 1 to 2 mgkg−1. The concentrations observed in the water samples and superficial sediments suggest that some of the Hg historically discharged into the lagoon may have been exported to the Atlantic Ocean coastal waters. Bioaccumulation of Hg in fish tissues shows the usual dependence on species, territoriality, feeding habits and size. Concentrations as high as 25 mgkg−1 fresh weight have been observed but the average values do not exceed the EEC quality objective of 0.3 mgkg−1 (EEC, 1982).

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Seals of the Pack Ice

Oryx ◽

10.1017/s0030605300038230 ◽

1955 ◽

Vol 3 (2) ◽

pp. 75-88

Author(s):

Harry R. Lillie

Keyword(s):

Polar Bear ◽

Barents Sea ◽

Harp Seal ◽

Bearded Seal ◽

Northern European ◽

Phoca Groenlandica ◽

Pack Ice ◽

Arctic Conditions ◽

Northern Atlantic ◽

Northern European Russia

Around the seas of the far northern Atlantic coming under the influence of Arctic conditions lives, frequently on the wander, one of the most delightful of creatures, the harp seal or saddleback, Phoca groenlandica. Large communities migrate in the Newfoundland, Labrador, Baffin Land, Greenland sector; others through the area of Jan Mayen Island towards Spitzbergen. Gregarious for much of the time, they share their world of ice with the occasional bearded seal and ringed seal, walrus, and polar bear. The White Sea in northern European Russia is a great harp seal nursery, for an eastern community in the area of the Barents Sea.

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