Status of harbour seals (Phoca vitulina) in mainland Norway

• Published in: NAMMCO Scientific Publications
• Main Authors: Nilssen, Kjell Tormod, Skavberg, Nils-Erik, Poltermann, Michael, Haug, Tore, Härkönen, Tero, Henriksen, Gunnar
• Format: Article in Journal/Newspaper
• Language: English
• Published: Septentrio Academic Publishing 2010
• Subjects: harbour seals; Norway; surveys; abundance; Vestfold; Finnmark; Nordland; Phoca vitulina
• Online Access: https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2672; https://doi.org/10.7557/3.2672

Harbour seals were counted along the entire Norwegian coast at known moulting haulout sites in the period mid-August to early September 2003-2006. In 2003-2005, almost all known moulting areas from Finnmark to Vestfold counties were covered by aerial photo surveys flown at altitudes of approximately 800-900 ft (243-274m), and at low tide (± 2 hours). Surveys in the Østfold County were flown in 2003-2006 at 300 ft (91m), and the small tidal amplitudes permitted counts to be carried out irrespective of the tidal cycle. In some sub-areas, two or three independent surveys were conducted. Visual counts using binoculars from smaller boats and islands were carried out in some selected areas. The surveys revealed a total minimum population of 6,705 harbour seals in Norwegian waters. Harbour seals were most abundant in the Nordland and Sør-Trøndelag counties with minimum estimates of approximately 2,500 and 1,500 seals, respectively. The presented minimum estimate is approximately 800 seals lower than an estimate obtained in a comparable study carried out during the moult in 1996-1999. Increased anthropogenic removals, and the phocine distemper virus (PDV) epidemic in the Skagerrak region in 2002, may have contributed to the current lower estimate.