It doesn’t feel that long ago that I was saying my goodbyes to Orkney at the end of the pupping season last summer. Well, we are back now and actually already two weeks into our 4th field season of this project (well, 5th year of fieldwork, but 4th photo-identification data collection year!). There is always a sense of excitement the first day going back to the field sites after all these months. Since we left at the end of last July, these harbour seals have undergone an annual moult (around August), a mating season, and a whole autumn and winter of foraging in the North Sea waters, and for the females, also preparing to pup again this summer. It was thus nice to recognize some familiar faces, like Or008 and Or023, two females that are frequently seen in a small haulout site in Widewall Bay, in South Ronaldsay. I normally do not tend to photograph seals in the water, as it is more difficult to get good head profile photos, but these two were posing just perfectly for me!
Harbour seals tend to come back to the same haulout sites every summer for the pupping season. That alllows us to follow the same individuals over the years, recognizing them based on their unique pelage markings, and noting relevant information to answer our research questions. It is of course possible that we might see some seals only once in the entire summer, while others are seen on a daily basis. Not all seals follow the same pattern, but, in general, they tend to be at a haulout site at some point or another during the season. As long as we go out regularly to check on them, we should be able to photograph them and thus have a record of their presence! Sometimes, however, we might not see one or more seals at all. That could be because they are elsewhere, or we just do not manage to see them when they are around, or they have have died; the numbers of harbour seals in Orkney have been declining continuously at a rate of 10% each year since 2001. The last count in Orkney and the North coast was in August 2016, when 1,349 harbour seals were counted compared with 1,938 in 2013. Overall, the composite counts for the North Coast & Orkney Seal Management Unit (SMU) have declined from approximately 8800 in the mid-1990s to 1350 by 2016, representing an 85% decrease in what was the largest single SMU population in the UK. The counts for the Sanday Special Area of Conservation show a similar trend, with a step change between 2001 and 2006 and a continuing decline at 17.8% p.a. (95% CIs: 13.3, 22.0) since 2006. There is more detailed information on the counts and population trends of grey and harbour seal populations in the annual reports to the Special Committee On Seals (SCOS), which can be found in the SMRU website (see this link). By collecting this annual data on presence/absence of known seals and their associated pupping history we can learn about their survival and birth rates, and how these help explain the observed declines, increases or stable trends in different areas in Scotland.
So far the weather in Orkney has been… well, Orkney weather. I’ve had dense fog, beautiful sunshine, incredibly strong wind, thuder and lightning, heavy rain and a gazilion midges. Despite that I’ve managed to get out more or less every day to check on the seals. The numbers have been increasing at the monitored sites, with more heavily pregnant females. Then on June 12th I saw the first pup! It was in Widewall Bay, where Or075 decided to haulout with her new pup as I was getting out of the car. Good timing!
Since then there are at least another two pups in that same haulout site, from females Or007 and Or135. At another monitored site in Burray, as of yesterday 17th of June I have identified 4 pups, belonging to females Or024, Or025, Or065, and Or146. I am expecting to see a few more in the next week or so, at least by the looks of some of the females such as Or142… ready to pup!
Written by Monica