scholarly journals Monitoring trends in the abundance of harbour seals (Phoca vitulina) in Icelandic waters

2010 ◽  
Vol 8 ◽  
pp. 227 ◽  
Author(s):  
Erlingur Hauksson
Keyword(s):  
Coastal Area ◽  
East Coast ◽  
Aerial Survey ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Northwest Coast ◽  
Coastal Regions ◽  
Harbour Seals ◽  
Seal Population ◽  
Icelandic Waters

Harbour seal (Phoca vitulina) numbers along the coast of Iceland were monitored by aerial survey in the period 1980-2006. Trends in the abundance of the harbour seal population on the whole coast and in coastal regions of Iceland waters were estimated using ANCOVA on the survey counts, corrected for the influence of several covariates. Harbour seals were found in every coastal area, but were most abundant in Faxaflói, Breiðafjörður and on the northwest coast inthe beginning of this study. Harbour seal numbers declined significantly at a rate of rest = -0.04 (SE 0.005) yr-1 during this period. Decline was highest in Faxaflói and at the south coast (≅7%), while the east coast experienced a significant but lesser (≅1%) decline. Other coastal areas did not show significant trends. The northwest coast was the richest harbour seal area in Iceland in 2006. In Icelandic waters seals are commercially harvested, and unreported but probably high numbers of harbour seals are killed intentionally by shooting and accidentally in fishing geareach year. These factors likely contributed to the overall observed decline in seal numbers.

scholarly journals Vulnerability of harbour seals, Phoca vitulina, to transient industrial activities in the Strait of Dover

2005 ◽  
Vol 85 (4) ◽  
pp. 1015-1016 ◽  
Author(s):  
Laurent J.J. Seuront ◽  
Perrine Prinzivalli
Keyword(s):  
Interannual Variability ◽  
Industrial Wastewater ◽  
Anthropogenic Activities ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Industrial Activities ◽  
Dramatic Decline ◽  
Harbour Seals ◽  
Seal Population ◽  
Number Of Individuals

The abundance of the harbour seal (Phoca vitulina) was recorded on a tidal bar in the Dover Strait off Calais, over a six-year period between 1999 and 2004. Despite clear seasonal and interannual variability in the number of individuals hauled out on the bar, underwater activities devoted to the installation of industrial wastewater pipes conducted during seven weeks 1 km away from the bar led to a dramatic decline in the number of seals hauling out. A full 19 months after the end of the operations the harbour seal population had not recovered their initial abundance. The results of this study have critical consequences on the conservation of P. vitulina in areas impacted by anthropogenic activities.

Incidence of the Ascarid Porrocaecum decipiens in the Stomachs of Three Species of Seals along the Southern Canadian Atlantic Mainland

1958 ◽  
Vol 15 (4) ◽  
pp. 495-516 ◽  
Author(s):  
D. M. Scott ◽  
H. D. Fisher
Keyword(s):  
East Coast ◽  
Atlantic Cod ◽  
Atlantic Coast ◽  
Phoca Vitulina ◽  
The Other ◽  
Harp Seal ◽  
Harbour Seal ◽  
Halichoerus Grypus ◽  
Bay Of Fundy ◽  
Harbour Seals

Identifications were made of ascarids collected from 1948 to 1956 from the stomachs of 318 harbour seals (Phoca vitulina), 812 harp seals (P. groenlandica), and 127 grey seals (Halichoerus grypus) killed in several localities along the Atlantic coast of Canada. Porrocaecum and 2 other genera of ascarids, tentatively identified as Anisakis and Contracaecum, were present in each species of seal. All 112 male Porrocaecum that were identified to species were P. decipiens.Almost all stomachs of harbour and grey seals at all seasons and in all localities contained P. decipiens. Considering all localities, the overall average incidence was about 20 adult P. decipiens in harbour seals and about 100 in grey seals.P. decipiens was normally much rarer in the stomachs of harp seals than in the other seals. It appeared most frequently in harp seals taken around the Magdalen Islands in April and May. The incidence of adult P. decipiens was much lower during the breeding season of the seals and during their southward and northward migrations within the Gulf of St. Lawrence. The incidence of P. decipiens in harp seals from the east coast of Newfoundland was very low.The relative importance of each species of seal as a vector of P. decipiens is as follows. The harbour seal is the most important in the Bay of Fundy and along the southwestern coast of Nova Scotia. Elsewhere harbour and grey seals occur in approximately equal numbers. In such localities the grey seal is probably more important than the harbour seal. The harp seal is about 100 to 200 times as numerous, while in the southwestern Gulf of St. Lawrence, as the combined populations of harbour and grey seals there. Despite this great numerical superiority the harp seal does not appear to be more important than the other seals as a host of P. decipiens.The relation between each species of seal and the incidence of larval P. decipiens in Atlantic cod (Gadus callarias) is discussed.

scholarly journals Review on utilization and research on harbour seal (Phoca vitulina) in Iceland

2010 ◽  
Vol 8 ◽  
pp. 341 ◽  
Author(s):  
Erlingur Hauksson ◽  
Sólmundur T Einarsson
Keyword(s):  
Phoca Vitulina ◽  
Economic Resources ◽  
Harbour Seal ◽  
Legal Rights ◽  
Large Dataset ◽  
Harbour Seals ◽  
Seal Population ◽  
By Catch ◽  
Catch Statistics ◽  
Anisakid Nematodes

Harbour seals (Phoca vitulina) have been harvested in Iceland since the first settlers arrived in the 9th century. Pups were generally netted, clubbed and harpooned until 1875 when general use of guns for hunting began. Seal-hunting has been traditional amongst the farms legal rights. Seal hunting was an important supplement to other economic resources. Harbour seal skins, salted ordried, were exported and large dataset of catch statistics is available from trading logbooks since the late 19th century. In the early 20th century catch was about 6,000. In the ‘bounty’ period 1982 – 1989, maximum catches were of 4,000 animals with about 350 hunters participated; in 2006 catches were only about 100 animals with 18 hunters. After 1989 the population continued to decline even though catches decreased markedly. Unreported by-catch in fishing gear, hunt for local consumption and shooting of seals swimming in salmon rivers estuaries may have kept the total removal from the stock above sustainable levels. A considerable Icelandic knowledge base had been compiled about the biology of the harbour seal since the late 16th century, with the first written reference in 1588-1589. In the last decades, research on various aspects of its biology and monitoring have been intensified, with focus on abundance, distribution, diet and nematode infestation. The main results show that the Icelandic harbour seal population - has declined annually about 5% in the period 1980-2006, - was most abundant on the NW-coast, - feeds mainly on sand-eels and gadoids, - and was less infected with anisakid nematodes than grey seals. Seal watching, as a low-consumptive indirect utilization, may represent a new economical opportunity if properly regulated.

Comparison of the healing process in hot and cold brands applied to harbour seal pups (Phoca vitulina)

2006 ◽  
Vol 33 (5) ◽  
pp. 361 ◽  
Author(s):  
Pierre-Yves Daoust ◽  
G. Mark Fowler ◽  
Wayne T. Stobo
Keyword(s):  
Healing Rate ◽  
Healing Process ◽  
Phoca Vitulina ◽  
Hair Follicles ◽  
Harbour Seal ◽  
Short Term ◽  
Long Distance ◽  
Macroscopic Appearance ◽  
Short Term Study ◽  
Harbour Seals

Hot branding has been used for many years by researchers to identify seals from a long distance. In livestock, cold branding has been proposed as an alternative because it is thought to be less painful. The purpose of this study was to compare the healing process of hot and cold brands applied to harbour seal pups (Phoca vitulina). A total of 306 animals was branded with a unique set of four characters: three applied for 3–5 s with an iron heated to 500°C, and one applied for either 10 or 20 s with an iron frozen to –175°C. At three subsequent times over 10 weeks, 43, 41 and 51 animals, respectively, were recaptured, the macroscopic appearance of their brands recorded, and biopsies taken for microscopic examination. Cold brands had a faster healing rate than hot brands. However, they resulted in less destruction of hair follicles, and cold brands applied for 20 s caused more depigmentation. Regrowth of hair follicles could subsequently obscure brands, while depigmentation reduces the contrast between the brand and the surrounding fur. Cold brands applied for 20 s also caused more extensive deep vascular damage, which subsequently may have resulted in deeper wounds in some of these brands. Yet, macroscopically, other cold brands, or portions thereof, were almost invisible. On the basis of this short-term study, the technique of cold branding that we used in harbour seals does not appear to be as reliable as that of hot branding to provide permanent legible brands.

scholarly journals Introduction: The harbour seal (Phoca vitulina) - a global perspective

2010 ◽  
Vol 8 ◽  
pp. 7 ◽  
Author(s):  
Arne Bjørge ◽  
Geneviève Desportes ◽  
Gordon T Waring ◽  
Aqqalu Rosing-Asvid
Keyword(s):  
North Atlantic ◽  
Phoca Vitulina ◽  
Global Perspective ◽  
Harbour Seal ◽  
The North ◽  
Harbour Seals ◽  
The North Atlantic ◽  
The Baltic

Introduction to Volume 8: Harbour seals in the North Atlantic and the Baltic 

scholarly journals Observations on seals on the island of Surtsey in the period 1980-2012

2015 ◽  
Vol 13 ◽  
pp. 41-43
Author(s):  
Erlingur Hauksson
Keyword(s):  
Breeding Site ◽  
Phoca Vitulina ◽  
The Other ◽  
South Coast ◽  
Harbour Seal ◽  
Halichoerus Grypus ◽  
Grey Seal ◽  
The South ◽  
Breeding Sites ◽  
Harbour Seals

Grey seals (Halichoerus grypus Fabricius) and harbour seals (Phoca vitulina L.) have been surveyed on the coasts of Iceland since 1980. During the period 1980-2012, both seal species have declined markedly in numbers at the Icelandic coast. The grey seal has established a considerable breeding site on the northern spit of the Surtsey island. This is at present one of the biggest grey seal rookeries on the southern shores of Iceland, with estimated about 60 pups born there in the autumn of 2012. On the other hand, the harbour seal has not been numerous on Surtsey during breeding time in the summer. Breeding sites of harbour seals on the south coast of Iceland closest to Surtsey are in the estuaries of the glacial rivers Ölfusá, Þjórsá, Markarfljót and Kúðafljót. Harbour seals, however, haul-out in great numbers on the northern shores of Surtsey during the winter, presumably using the island as a resting place after foraging in the adjacent waters.

scholarly journals Historical trend in harbour seal (Phoca vitulina) abundance in Iceland back to the year 1912

2010 ◽  
Vol 8 ◽  
pp. 147 ◽  
Author(s):  
Erlingur Hauksson ◽  
Sólmundur T Einarsson
Keyword(s):  
Population Decline ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
Early 20Th Century ◽  
Fishing Gear ◽  
Early 19Th Century ◽  
Harvest Rate ◽  
Aerial Surveys ◽  
Seal Population ◽  
By Catch

The harbour seal (Phoca vitulina) is Iceland’s most abundant seal and has likely been exploited since the settlement of the country. Detailed information on skin exports is available as far back as 1912, and suggests that the catch, consisting mainly of pups, was far higher in the early 20th century than now. Assuming that skin exports were proportional to catches, these data were used to back-calculate the size of the Icelandic harbour seal population to the year 1912. The results indicate that the harbour seal population was considerably larger in the early 19th century than at present, about 60,000 (90% CI:40-100) animals. Aerial surveys conducted since 1980 indicate that the population has declined from 33,000 (90% CI:26,000-44,000) animals in 1980 to about 12,000 (90% CI:9,000-16,000) animals in 2006. The population time series suggests thatthe stock began to decline rapidly around 1960 and continued to decrease until 2003. In the period 1980 - 2003, the population declined even though reported catches were relatively low. Harvest rate had probably been about 10% before 1960. Between 1960 and 1980 the reported harvest rate increased to about 13%, but unknown numbers of adult seals were also taken as by-catch and shot in defence of salmon rivers. Since 2003, total removals have decreased and the population decline appears to have ceased. Entanglements in fishing gear and other incidental unreported hunting could increase again in the future. Therefore, the population must be monitored on a regular basis, and better information on by-catch and other unreported harvest is needed.

The seal louse, Echinophthirius horridus: an intermediate host of the seal heartworm, Dipetalonema spirocauda (Nematoda)

1981 ◽  
Vol 59 (7) ◽  
pp. 1457-1459 ◽  
Author(s):  
J. R. Geraci ◽  
J. F. Fortin ◽  
D. J. St. Aubin ◽  
B. D. Hicks
Keyword(s):  
New England ◽  
Intermediate Host ◽  
Developmental Stages ◽  
Phoca Vitulina ◽  
Harbour Seal ◽  
First Report ◽  
Harbour Seals

Heartworms, Dipetalonema spirocauda, are common in harbour seals, Phoca vitulina, that strand along the New England coast. Lice, Echinophthirius horridus, taken from a stranded harbour seal infected with seal heartworm carried three developmental stages of D. spirocauda. This is the first report of an intermediate host of the seal heartworm.

Abundance and maturity of three species of parasitic anisakine nematodes (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex) occurring in Sable Island harbour seals (Phoca vitulina)

2002 ◽  
Vol 80 (3) ◽  
pp. 442-449 ◽  
Author(s):  
Wayne T Stobo ◽  
L Paul Fanning ◽  
Brian Beck ◽  
G Mark Fowler
Keyword(s):  
Prey Species ◽  
Phoca Vitulina ◽  
Final Host ◽  
Anisakis Simplex ◽  
Halichoerus Grypus ◽  
Commercial Fish ◽  
Pseudoterranova Decipiens ◽  
Harbour Seals ◽  
Seal Population ◽  
Contracaecum Osculatum

Three species of anisakine nematodes (Pseudoterranova decipiens, Contracaecum osculatum, Anisakis simplex) co-occur in the stomachs of Sable Island harbour seals (Phoca vitulina). The sealworm, P. decipiens, was the commonest nematode in these seals. Anisakis simplex was found in much smaller numbers, none mature, indicating that the harbour seal is not a true final host to this parasite. Contracaecum osculatum was rare but half were mature. Pseudoterranova decipiens increased in abundance with size of the seal. An inverse relationship was observed between P. decipiens abundance and the age of seals of similar size, probably owing to changes in diet. Numbers of P. decipiens may have declined over the summer, coincident with an increase in the proportion of mature worms in the stomach. From similarities between the worm infections of grey seals (Halichoerus grypus) and harbour seals, we infer that A. simplex abundance may also exhibit a decline in abundance. Contracaecum osculatum was only encountered during the latter half of the year, suggesting an association with prey species of corresponding periodicity in their distribution. We estimate that the abundance of sealworm in harbour seals is about 2.5% of that carried by the grey seal population. This could imply that harbour seals represent an insignificant vector of the sealworm infecting commercial fish species in the Northwest Atlantic, provided density-dependent relationships exist between worm abundances in different host species.

scholarly journals The status of harbour seals (Phoca vitulina) in the United Kingdom

2010 ◽  
Vol 8 ◽  
pp. 117 ◽  
Author(s):  
Dave Thompson ◽  
Callan Duck ◽  
Mike E Lonergan
Keyword(s):  
Survey Methods ◽  
Harbour Seal ◽  
Rocky Shores ◽  
The North ◽  
Harbour Seals ◽  
General Decline ◽  
Seal Population ◽  
The Status ◽  
Thermal Imagers ◽  
The Uk

The UK holds approximately 40% of the European harbour seal population, with the majority found around the coasts of Scotland. Harbour seal populations in the UK have been monitored through a series of repeated aerial surveys of animals hauled out during the annual moult in early August. This moult count is used as a consistent index of population size. Survey methods and frequencies vary. The Scottish and English east coast populations mainly haul out in tidal estuariesand are surveyed annually, using fixed wing aircraft and digital photography. Populations in north and west Scotland often haul out on rocky shores and are surveyed less frequently, using helicopters fitted with thermal imagers. Overall, the most recent minimum estimate of the UK harbour seal population is 24,250 seals of which 19,800 are in Scotland, 3,200 in England and 1,250 in Northern Ireland. The results show that the number of harbour seals in eastern Englandwas increasing before the 1988 and 2002 phocine distemper (PDV) epizootic but has not increased since the end of the 2002 epizootic. There is also evidence of a general decline in most of the large harbour seal colonies around Scotland. The populations along the north and northwest mainland coast were an exception, with numbers appearing to be stable. Between 2001 and 2008, the population in Orkney declined by 67% and Shetland declined by 40%, indicating harbourseals in these areas experienced substantially increased mortality or very low recruitment over this period. The widespread declines, ranging from Shetland to The Wash, suggest that the causes may have been present over a large part of the North Sea and waters off western Scotland.

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