Harbour Seal Decline Project

Patience is definitely a necessary virtue here in Kintyre, as pupping appears to start a good few weeks after everywhere else that we are surveying. However, I have finally spotted our first pups of the season here in Kintyre. I photographed two different mum and pup pairs on the 26 June at a site known as Island Muller, just north of Campbeltown. Last year, the first pup was observed on 23 June – so it is no surprise that I would have to wait a bit longer than the rest of the teams to see some pups.

This was the same seal photographed on 23 June 2017 – looking pretty large and evidently ready to pop:

And here is the second mum-pup pair seen in Kintyre:

The Island Muller site is interesting because a number of seals often haul out on skerries in the northern part of the small bay as the tide is going out, and then transfer over to a more extensive network of skerries in the southern part of the bay once the tide is sufficiently low for these to be exposed. This is great because it gives me two opportunities to photograph some of the seals. This is particularly useful if any of those hauled out on the northern skerries are in a position where I cannot photograph the sides of their heads or if they are being super lazy and not moving at all.

There have been a good number of obviously pregnant seals at the Muller Island site so I am looking forward to seeing more pups appearing over the next week or so.

Written by Craig.

Pupping season is well underway in Orkney. Over the last few days, the number of both seals and pups has increased at the main haulouts, with less and less pregnant looking females and more tiny pups disturbing the quiet and peace of the haulout sites. Breeding season is a critical time in the life cycle of harbour seals, and so it is for us. One of the main objectives of the current project is to collect data on birth rates for harbour seals in areas where numbers of harbour seals are declining (such as Orkney) and in areas where the numbers have been stable or increasing (such as the West coast). During this time, we focus our effort at haulout sites that we know are used for pupping, and we try to visit them on a daily basis, weather permitting. So far, the weather in Orkney has allowed for almost daily visits to the selected haulout sites.

When collecting data, we photograph as many seals as possible, ideally taking photographs from both sides of the head. If we see any obvious signs of pregnancy we will take notes to later on link those to specific photographs taken. The same goes if we can see a pup with a seal, but maybe we cannot manage to photograph the pup properly because it is hiding behind mum.

 

 

The first pups were seen in Orkney last week, with the first one being born to one of the females we tagged earlier in April. Just a few days later, another of the seals we tagged in that trip gave birth to her pup. She was seen at the haulout for a few days with a massive belly and looking rather uncomfortable. She is female Or085, known from our catalogue from last year. This female had spent the last few weeks, since she was tagged on 30th of April 2016, traveling and foraging around Scapa Flow, before returning to Burray to pup.

Births are a fairly quick business in harbour seals. When close to giving birth, seals can be observed changing position frequently, rather than resting still for long periods. Contractions can be observed and normally the birth will not be far from that point in time. Studies in Atlantic harbour seals near Newfoundland showed that the mean time from the onset of obvious contractions to birth was 3.5 minutes, with a minimum of 38 seconds and a maximum of 21 minutes (Lawson and Renouf 1985). That study also showed how newborn pups were very active, immediately trying to crawl and touch nearby objects. New mums can be seen making many nose-to-nose contacts.

Yesterday I missed the birth of two pups right in front on my eyes. The fact that the haulout-site is located in a rocky and weedy shore does not help, as I do not have full view of all the hiding places. When I arrived at the haulout I distinguished a seal with remaining of blood in her genital area as well as the face and flippers. After a while I distinguished a tiny pup behind her, who must just have been born.

Another seal kept moving further away from the water’s edge, and finally settled in a spot among the seaweed covered rocks. I photographed this seal the day before, when I noted she was massively pregnant. A while after, I saw there was more movement and suddenly a little head showed up! By then the female was busy checking on the pup while moving in circles to force the placenta out, check the video below! It did not take long for a group of great black-backed gulls to show up and take an opportunity to take advantage of the placenta. The pup was actively moving around, and the female kept on checking on it, while scaring off the group of seagulls. By the end of my watch the pup was suckling, and as the tide came in mum and pup went into the water. I will keep my eyes peeled today to see if I can photograph the pair again.

 

Post written by Mònica

Pupping season has officially started in our Orkney and Isle of Skye study sites! Both Andy and myself saw the first pups during the weekend. Craig is patiently waiting to see the first one while monitoring the pregnant females at selected haulout sites along the Kintyre coast.

Pups have a lanugo coat (white fur) while inside mum which they will shed before birth, so that when they are born pups already have their dark spotted adult coat. The pup seen in Loch Dunvegan seems to have a bit of white fur remaining, which can happen. Hopefully it’s only that and not a sign of having been born a bit too early. The pup, which had been seen by the boatmen at Dunvegan Castle for a couple of days before Andy saw it, cannot be more than a few days old, as the umbilical cord is still visible.

In Orkney, the first female seen with a pup was actually one of the seals we tagged last April. She is female Or021 in our catalogue and she was already a recapture from 2016. Last year she was not seen with an obvious pregnancy or with a pup, but this year the story is obviously different.

I photographed Or021 last Wednesday, without a pup yet but with a big belly instead, and then saw her with her new pup on Friday and missing the extra belly. Checking on the seals on an almost daily basis allows us to estimate birth dates with a smaller error than if we only went once a week for example. In this case, we know the pup was born sometime around Thursday 8th June (plus minus one day). On Sunday I went out and saw her again at the same haulout with her pup, who was suckling while she was taking a rest.

The second pup showed up during the weekend, as I checked the main pupping site in Burray. I could not see the pup to start with, just an adult seal checking on what looked like a wet dark rock hiding among the seaweed. That was no rock but a newborn pup! I must have just missed the birth, as the placenta could still be seen next to mum. Mum and pup made a lot of nose to nose contact while I was there. This female, which is Or148 in our catalogue, is a rather young looking female, based on her size compared to other adults. Last summer we photographed her, but never pregnant or with a pup, so this could well be her first pup. Female harbour seals reach sexual maturity around age 4, meaning they can start having pups around age 5. We will keep monitoring this and other females at the haulouts during the pupping season. By the look of it, things are about the get noisy and hectic at the haulouts!

Written by Mònica

The second year of photo-identification collection has officially started in all three study sites, with Andy going out on the boat seal trips at Dunvegan Castle, Craig having settled in beautiful Kintyre coast and myself checking on the seal haulouts in Orkney. The first taste of photoID in Orkney was during our trip earlier in April to capture and release harbour seals in order to collect individual data on health condition as well as to deploy telemetry tags.

During the first day out taking pictures we came across a group of 17 seals hauled out in Burray. I managed to photograph around 14 of those but had to give up on a few that were so comfortably sleeping that would not move at all to give me a view of the pelage pattern in their head. Once back in the office I checked the pictures and realized that I already had 13 of those seals in the catalogue of seals from last summer!

For example we saw Or146, a male harbour seal already photographed in 2016, who actually was seen fighting with another male last summer, as seen in the second video in this blog entry from last year.

We also spotted a known female, Or020, who we captured and released last year and then subsequently photographed during the pupping season. Last summer she had a pup, and by the looks of it she is likely to be pregnant again.

We also saw a couple of younger seals, which sometimes prove a bit more difficult to identify if their spot pattern in the pelage is not so well defined. However, that was not the case for this little female, Or105, already photographed last summer.

We have not seen pups yet, but the first one cannot be far away from being born as the haulouts fill with pregnant females. Last week I photographed Or045, a known female from last summer, who had a pup last year and is currently very pregnant, as you can see in the photograph below.

Information such as this will be recorded on an annual basis for all known and new females that enter the catalogue, and will help build up a database of information on which females were seen each year and whether they were seen with a pup or not. We will use such data to estimate birth rates in the different study sites. We can then compare those birth rates in study sites of contrasting population trajectories (e.g. study sites where the number of harbour seals have been declining or where they have been stable or increasing), which on its own will be very interesting given the very different population trajectories at different study sites (e.g. Orkney versus Isle of Skye). These birth rates together with survival rates that we will also estimate from the photo-ID data, can inform a population model for harbour seals. This model, which simulates what happens in a population over time, can be tweaked around with different scenarios of birth and mortality rates to understand which scenarios might be representative of the different population trajectories.

Meanwhile we will be going out to take pictures on a daily basis when the weather allows, counting the days until the first pup shows up… That day can’t be far given the activity in some of the females bellies! Check this wriggly pup in the video below:

Following our trip to Isle of Skye I had a couple of weeks of office based work, which allowed me to catch up with some of last year’s photoID data but mainly to finish organizing the upcoming photo-identification season at the project study sites in Dunvegan (Isle of Skye), Kintyre (West coast) and Burray and South Ronaldsay in Orkney. Once protocols, equipment and logistics had been organized it was almost time to head up to Orkney for our second trip in this study area to capture and release harbour seals in order to collect individual data, as we did last year. Like the 2016 trip and the recent Isle of Skye trip, the objective was to capture a number of harbour seals and collect individual data regarding their body condition and health, as well as to deploy telemetry tags on a sample of the adults. This information, collected annually and in different areas of contrasting harbour seal population trajectories, will help us get a better picture of what may be behind the decline in harbour seal numbers in the north and east coast of Scotland and in the Northern Isles, compared to the stable and in some areas increasing numbers of harbour seals in the west coast and Outer Hebrides.

In mid-April we headed up to Orkney, aiming to finish the work within a couple of weeks. Despite having a rather summer-like weather at the start, things turned around very quickly and we were suddenly in proper autumn and winter weather for a good week and a half. We had snow, hail, and wind. And more wind, lots of it, which made working outdoors and in the water rather challenging. The team found extra energy where we thought we did not have it and we were out at every opportunity we had, working double tides if needed.

 

 

 

 

 

 

 

We were not the only ones disliking the weather though. Not surprisingly, the seals did not enjoy the heavy winds and chose not to use most of the haulouts where they normally would regularly come ashore to rest and decided instead to stay in the water, use haulouts out of our reach or only use those more sheltered. In addition to our limited ability to work given the bad weather conditions, most of the seals we captured in the first couple of weeks were mostly males, similar to what happened during our trip to Isle of Skye. This could have been caused by a segregation in the use of haulouts between the two sexes or maybe just by being unlucky and getting more males caught then females. Despite the challenging conditions our female scoreboard slowly started to fill up. A couple of calm and sunny days allowed us to travel further away to check on other haulouts around Scapa Flow, and we successfully caught another few harbour seals.

 

Overall, we captured and released around 20 harbour seals of different sexes and age classes and deployed telemetry tags on eight of the adult females. The tags, which are small and lightweight, are glued to the back of the head of the seals and will provide with detailed information on their location, movements and diving behaviour until they fall out sometime close to the start of the annual moult in late July and August.

Despite tagging a very small proportion of the total population, the data we obtain from the telemetry tags are useful and interesting in many ways. For example, the location of the seals will inform and guide the photo-identification effort during the pupping season. Also, by looking at where and how often tagged seals use certain haulouts where the photo-identification data are collected, we can understand how representative our selected study sites (and the results coming out of those) are of the total population of harbour seals in Orkney. The telemetry data can also inform us about potential foraging areas, where we can get fish samples from to look at the prey availability and quality.

The telemetry tags have been reporting back frequently and, similar to last year’s deployments, showing a variety of movements among the seals. The figure below shows the tracks of all 8 adult female harbour seals. For now most of the females have stayed within Scapa Flow or just south of it off Hoy and South Ronaldsay, but one female has taken a trip north to Shapinsay and from there she has been doing longer trips off the NW coast of Orkney mainland. For me I will keep a close eye on the whereabouts of these females, especially as we are approaching the peak in the pupping season in about three weeks’ time. Hopefully I will get to see some of them with their pups while I take pictures, and we can compare my observations with the results from the pregnancy tests conducted during the captures as part of the data collection on individual health status.

I almost forgot! We had an unexpected visit while we were up in Orkney, with a group of three fin whales showing up in Scapa Flow. The good weather conditions and the unusual sight filled up the roads between Burray and Kirkwall with curious observers. What a treat!

Blog post written by Mònica

It has been a long time but we are back to update on the Harbour Seal Decline Project! We spent most of the autumn and winter processing all the data that were collected during 2016 (keep tuned for updates on that!). After months of office based work we were out again on our first fieldwork trip of 2017. In this first trip we headed up to Isle of Skye in early March, with the objective of capturing and releasing harbour seals to obtain individual data on their health and condition as well as deploying telemetry tags. The sites chosen to capture seals are located in Loch Dunvegan, and include the skerries where later on in the summer Andy will be collecting photo-identification data of the seals in collaboration with the Dunvegan Castle seal boat trips. These haulouts in Isle of Skye represent our study area where numbers of harbour seals have been stable or increasing, compared to haulouts located in our other study area in Orkney, where numbers have been declining by 75% since around the year 2000.

After a long day on the road we arrived to Dunvegan Castle where we met with some of the staff who very kindly showed us how to access the boat slip. The sight of around 100 seals hauled out right opposite to the boat slip was a nice welcome. However, the weather did not want to play the game and we had a good share of rain, wind and hail, with temperatures below 5 degrees for a good week. Given these conditions we started by checking out the more sheltered skerries close to Dunvegan Castle. During the first catching attempts we kept on capturing adult males, but not a single female, suggesting different haulouts might be used differently depending on age and sex.

To try and have a better idea of haulout composition, we took a road trip with the scope and the camera . The photographs confirmed that the haulouts we were targeting were dominated by males. We then learned that the boatmen in Dunvegan had named one of the skerries as ‘male island’… no surprise there! This segregation between haulout sites is known to occur in harbour seals, as other studies have shown (see for example the study by Thompson 1998 on harbour seals in Loch Fleet, Moray Firth, or the one by Harkonen and Harding 2001 in Norway.)

In the current study we are mostly interested in adult female harbour seals, as information on their survival and birth rates will be compared between sites of contrasting population trajectories. With the hope of encountering a higher proportion of females we waited for a window of good weather and traveled to haulouts closer to Skinidin and Colbost. Luckily for us those haulouts had a better male to female ratio.

After the slow start we finally started to get more females, and deployed 8 GSM-GPS telemetry tags on adult females. These are the same type of tags that were deployed last year in Orkney, and will inform us about the movements and diving behaviour of the seals, as well as their whereabouts during the pupping season. The combination of snowy days and a last day of pure sunshine and calm seas left us with incredible views of The Cuillins. Since the tags were deployed we have been receiving regular updates on the seals’ location and movements. Below are maps with the movements of some of the tagged seals, showing individual differences in the extent of the movements as well as the areas visited by each of them.

The tags, which are glued to the back of the seal behind the head will stay on until they fall during the moult sometime in late July or August. During the pupping season they will inform us on the seals’ whereabouts, and hopefully the seals decide to stay around Loch Dunvegan for Andy to check on them and (hopefully) on their pups. Keep tuned for updates on these Skye seals and on our other trip to Orkney!

That’s it, after weeks of taking photographs, counting seals and looking for mum-pup pairs, 2016 fieldwork season has reached the end! The weather has unfortunately kept me indoors on my last day, and with that finish 80 days of going out on the field since the end of March, over 200 visits to haul out sites and more than 11,000 photographs taken in Orkney! Craig has also finished the season in Kintyre, and Andy will go out to check on the seals at Loch Dunvegan this upcoming weekend for the last time this year.

It has been a very intense but rewarding season. I have enjoyed spending so many hours out in the field observing the seals, and generated tons of (hopefully) great data. The good weather also helped, allowing me to go out almost everyday, missing on just a few very rainy days.

Some of the telemetry tags that were deployed back in April are still attached to the seals and sending information on their location, movements and diving behavior. The rest have stopped transmitting likely because they have fallen out with the seals’ undergoing their annual moult, as expected.

One of the seals that still has the tag on is a male with tag number 260 (see picture above), which I have lately seen hanging around at one of the haulout sites in Burray. He was initially tagged on March 14th 2016 in Widewall Bay and since then he has been moving within and out of Scapa Flow, spending a lot of time between Flotta and Burray.

When I took the previous photograph, this male had just come out of the water to haulout. After a while though, as the tide came up, he was not there anymore, and I couldn’t figure out where he had moved to. As I took my eyes from the camera and looked towards the water I spotted him silently checking on me, just a few meters away! I do sometimes wonder who is the one checking on who here…

The haulout sites will continue with their activity after I leave, with the last few pups being weaned, mating season already started and all seals except this year’s pups undergoing their annual moult. A few days ago I captured on video two males getting into a fight once again. The smaller of the two seals initially approached the bigger one just to exchange some growling, the bigger male not being too worried. Despite his much smaller size though, the youngest of the males ended up taking up the fight, to my surprise and, I think, the opponent’s!

Ahead of me there are a good few months of data processing and analysis. All those pictures that have been taken need to be graded for quality and then each seal needs to be identified in order to build a catalogue of seals in each area. These catalogues will be used when we come back in the following summers, to construct a sighting history for each identified seal, allowing us to look at the fate of each individual over time and estimate their survival rate. The pictures and observations taken this year will also allow us to know which females were seen with and without a pup, which will be used to estimate fecundity rates in each area.

Observing the seals has been great fun, and I have also enjoyed spending all these weeks in Orkney, what an amazing place! I am happy to have met and talked to so many people during my time here, and I am very grateful to the many land-owners that have allowed me to drive through and park in their properties at all times and days of the week in order to get to the haul out sites.

For now it’s a goodbye to Orkney and the seals, although I will be seeing them in photographs over the next few months. Keep tuned to this blog as I will update with news on how we are getting on in the upcoming months. Few fun seal pics to finish off!

Written by Monica

We are approaching the end of the fieldwork season for this summer, which means the seals already have or are about to start their annual moult. All seals undergo an annual moult during which they progressively lose and regrow their hair. For harbour seals, and in Scotland, moult season starts sometime at the end of July or start of August. The first seals to do so are the yearlings, which are the seals born the previous summer, by now over a year old and thus the ones with the oldest coat compared to the other age classes. During that period, the pattern of spots that we normally use to ID each individual seal is much more difficult to distinguish as it temporarily disappears under the old brown hair.

At the haul out sites I visit in Orkney some of the yearlings and younger seals are well under way with their moult, as you can see in the picture above. The new hair, which is much darker, shows under the brown old hair, making them more similar to this year’s pups. Sometimes I need to think about it twice to decide if a seal is a yearling or one of the bigger pups from this year!

A study by colleagues at SMRU looked at how harbour seals regulated their surface temperature during the moult (a link to the published paper can be found here). The study showed that when moulting, the seals’ skin got very hot as they must circulate blood close to the skin surface to allow hair to grow quickly. That requires spending a lot of energy during the moult. To avoid losing too much heat, the seals increase the periods of time spent ashore, and spend less time in the cold water where they would become chilled.

With the end of pupping season and the start of the annual moult, the haul outs are now busy, with the new pups from this year and the rest of the seals about to or already moulting and needing to spend more time ashore. This brings memories of what the haul out looked when I visited it around this time last summer.

With this number of seals the best spots to haul out are quite precious, and everyone is keen on getting them. Higher spots, those that will remain dry for longer as the tide comes up are especially good, as well as those that offer shelter from the wind and water spray on bad weather days. In the video below, a juvenile (on the right) has his eye on one of those perfect places, though occupied by an adult and much bigger seal. But being persistent pays off and he ends up getting it! I’d say he looks quite pleased with himself with this victory. This particular seal is quite easy to spot, as he has what looks like a dark band around his head. Just based on observations, it looks like, and for reasons unknown to us, that he is lacking hair in that area, causing that look.

Despite hauling out together, harbour seals do not seem to like having other seals too close. You can hear them growling and moving their fore flippers when other seals get too close. Even pups get annoyed with other pups or older seals! Last year, while doing fieldwork in Shetland, I observed the two pups in the video below having one of such arguments. If you wonder, the pup that is behind ended up accidentally rolling over himself and falling into the water! He then found another spot to haul out.

https://vimeo.com/176344563

Written by Monica

I’ve had a few busy weeks in Orkney as mum pup pairs have not stopped showing up at the different haulouts. The dynamics at the different haulouts have changed as weeks have gone past. At the start, I could observe a good number of mum pup pairs, easily identifiable as mums would not be far from their small pups in dry land or following them into the water when the little ones decided it was time for a swim.

Lately though, the haulouts are a bit quieter, with pups not calling constantly for their mums as some weeks ago. Despite being quieter, the pups keep the haulouts quite active, as they often go for swims, check on the neighbors and try their luck while testing the other seals’ patience when trying for a free feed from random females! In the following video you can see a good number of pups resting with a few adults, one of them being one of our tagged females.

The other thing is that, compared to a few weeks ago, there are now more pups seen on their own, maybe waiting for their mums to come back from a foraging trip. On a couple of occasions I’ve seen the awaiting pups being reunited with their mum, and the consequent long-awaited opportunity to suckle finally happening.

Females encourage their pups to suckle by positioning themselves on their side as well as using one of the fore flippers to guide the pup towards the nipples, as you can see in the video below. Identifying mum pup pairs is getting harder, as pups are more and more independent, and the interactions between adult seals and pups are not always that easy to interpret. For example, the mum pup pair featuring in the next video had been grunting at each other and play-fighting using the fore flippers for a while before the video was taken. At that point I would have thought it was an adult seal getting annoyed to have to wrong pup or just a pup too close!

When pups want to suckle, they are seen repeatedly touching mum with the nose and mouth, probably to make them turn around so that they can suckle. That does not always have the desired results, as mum has the last word. In the next video, a pup, who is behind the adult seal (its mum) has been suckling for quite a while before starting the video. Wanting more, the pup starts pushing mum from behind, but mum is not up for more suckling, making her point very clearly.

Suckling is not always a straightforward business, as we saw earlier in the month with a pup having to climb over a tiny rock to be able to suckle. Apparently, the mum’s bellybutton can be quite confusing during feeding! Check the wee pup below suckling and checking on the bellybutton in case that also provides milk!

Feeding time is exhausting, and there is nothing better then a nice nap after it, both for mum and pup!

Written by Monica

A couple of weeks ago I was taking photographs of seals hauled out at a skerry at Widewall Bay, in South Ronaldsay (Orkney). This haul out is frequently used by seals, although their numbers may vary from day to day. It seems to be a good place to rest for both grey and harbour seals, as it is surrounded by water that can be accessed easily, and it is currently used by mum and pup pairs in the area. The seals tend to spread along the skerry on its east side (the one facing the nearby beach) and slowly relocate towards the right end of the skerry as the tide goes down and dry sand surrounds the other end.

As the tide was going down and more area was getting exposed I observed a bulk of seaweed with a buoy and a seagull on it, which was very interested on something that was hiding below. As I looked closer, I saw what looked like a seal under the seaweed, and I suspected it had got entangled in maybe discarded nets or rope attached to the exposed buoy. I waited for the tide to go even lower and decided to check it out. When I got closer though, there were more bad news awaiting, as there were not only one but two dead harbour seal pups that had got entangled in the discarded nets. Very sad.

I took measurements and pictures of both pups in order to report them to the Scottish Marine Animal Stranding Scheme (SMASS), and retrieved the one that looked fresher to store until a postmortem necropsy can be conducted by staff at SMASS in Inverness. The pups were a male and a female entangled with either rope or nets, but that looked healthy otherwise. The discarded nets sit right in front of the haulout, and my guess is that the pups got curious in one of their adventurous swims, got entangled and it was too late by the time the tide came up again. Reporting dead seals, although sad, is a key element to this an any other project studying animal populations in Scotland. If you see a dead seal during a walk along the beach, you can contact SMASS to provide them with information on what you have found.

What I also realized is that those nets could cause more trouble if left there, but they were too heavy for one person to pull them out. Luckily I got in touch with Jenni, a biologist at the department of Development & Infrastructure at the Orkney Islands Council Marine Services in Scapa, who has been storing some samples for SMRU while we do our research in Orkney. She agreed something had to be done about those nets and very kindly offered to help. The next day she came to Widewall Bay with Madeline, another member of staff at the Marine Services, and joined Stuart and myself with their land rover, key to our success!

We quickly realized the discarded nets were huge and had been there for a very long time, as they easily broke off when pulled. We started by trying to dig out the part of the nets buried in the fine sand, under close observation by the seals hauled out nearby. We discovered a few different types of nets and up to four old buoys, completely full of water.

We tied a bunch of nets to a rope and to the land rover, and after a couple of failed attempts, the nets started to slowly move. Jenni drove the nets as far away from the haulout as possible, by the high tide mark. Once there, we cut out the buoys and pulled the nets by hand even further. At least these nets shouldn’t cause any more trouble to the seals in Widewall Bay. I am very grateful to Jenni, Madeline and Stuart for helping out, and to the Orkney Marine Services based in Scapa for the use of their land rover to successfully removing the discarded nets.

Written by Monica