TY - JOUR AU - Hiby, Lex AU - Lundberg, Torkel AU - Karlsson, Olle AU - Watkins, John AU - Jüssi, Mart AU - Jüssi, Ivar AU - Helander, Björn PY - 2007/01/01 Y2 - 2024/03/29 TI - Estimates of the size of the Baltic grey seal population based on photo-identification data JF - NAMMCO Scientific Publications JA - NAMMCOSP VL - 6 IS - 0 SE - Articles DO - 10.7557/3.2731 UR - https://septentrio.uit.no/index.php/NAMMCOSP/article/view/2731 SP - 163-175 AB - <div>The size of the year 2000 summer population of grey seals in the Baltic Sea was estimated using identification of individual seals from photographs taken over a period of 6 years. Photos were taken at haul-out sites within all major grey seal areas in the semi-closed Baltic Sea. The point estimate is 15,631, based on a value for annual survival of identification markings of 0.904, which was also estimated using the photo-id data, with 95% confidence limits from 9,592 to 19,005.&nbsp;<span style="font-size: 10px;">The estimate is subject to an unknown, but probably small, upward bias resulting from the risk&nbsp;</span><span style="font-size: 10px;">of failure to identify all individuals in the photographs used for the analysis. An estimated minimum&nbsp;</span><span style="font-size: 10px;">of 15,950 seals were counted at moulting haul-outs in 2003, which thus provides a lower&nbsp;</span><span style="font-size: 10px;">bound on the population size in that year and represents 80% of the photo-id point estimate.</span></div> ER -