Abstract
Harbour seals in Svalbard are the northernmost population of this species. This small population is comprised of ca. 1,000 individuals, most of which reside along the west coast of Prins Karls Forland (78°20’N). Satellite tracking studies have shown that adults are resident. Birthing occurs in the latter half of June. Newborns weigh about 11 kg and gain an average of 0.7 kg/d during the nursing period. Haulout patterns in Svalbard harbour seals are influenced by date (season), time of day, tidal cycle and temperature. Moulting takes place in early fall, first among juveniles, then in adult females and finally in adult males. Feeding studies show that polar cod (Boreogadus saida) is the dominant prey in terms of numbers, while Atlantic cod (Gadus morhua) is the dominant prey based on biomass, at least during the early autumn. Growth curves display significant sexual dimorphism with asymptotic values for standard length and body mass being greater formales. Testosterone levels inmales showed an abrupt increase at 6 years of age, while estradiol levels in females increased abruptly from age 4 years. The reproductive rate for adult females was 0.93. Longevity of Svalbard harbour seals is very short compared with populations from other areas.
Highlights
The harbour seals in Svalbard constitute the northernmost population of this species in the world
The main area of distribution of this species in Svalbard is off the west coast of Prins Karls Forland (Fig. 1 and 2), and the first trapper diary from this area that distinguished between harbour and ringed seals was from 1907-08 written by Peder Pedersen (Prestrud and Gjertz 1990)
In the scientific literature the occurrence of harbour seals in Prins Karls Forland is mentioned by Øynes (1964), and their occurrence is confirmed by observations and specimen collections by Benjaminsen et al (1973) and Krog and Bjarghov (1973)
Summary
The harbour seals in Svalbard constitute the northernmost population of this species in the world. The first reliable description of this species in Svalbard is from a harbour seal shot in 1898 west of Rossøya (ca 80.83°N, 20.00°E; Fig. 1) described by Römer and Schaudinn (1900). In the scientific literature the occurrence of harbour seals in Prins Karls Forland is mentioned by Øynes (1964), and their occurrence is confirmed by observations and specimen collections by Benjaminsen et al (1973) and Krog and Bjarghov (1973). Since this time, this population has been the focus of several scientific investigations, and the following is a compilation of results from these studies and a general status of knowledge for this unique harbour seal population
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