Monthly Archives: July 2016

End of 2016 fieldwork!

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.

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I cannot believe fieldwork is over!

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.

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Male with telemetry tag #260 in Burray on July 24th 2016

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.

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Movements of a male harbour seal with telemetry tag #260 between 14th March and 28th July 2016

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…

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Male with telemetry tag checking on me!

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.

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Two harbour seal pups resting

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Harbour seal pup taking a nap

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!

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Big male yawning and stretching…

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Balancing seal

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Seal pup suckling, look how big he is getting!

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Seal sticking its tongue out!

Written by Monica

Start of the annual moult

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.

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Juvenile harbour seal moulting

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!

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Pups are getting bigger!

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Harbour seals at different stages of the moult

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.

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Adult harbour seal moulting; the new hair can be seen underneath the old and brown looking one

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.

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Busy haul out about this time in 2015

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.

Written by Monica

Pups are getting bigger!

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.

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Harbour seal pup

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Pups are getting bigger!

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Harbour seal pup

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.

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Harbour seal pup suckling after coming out of the water

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!

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Wee pup yawning after suckling

Written by Monica

Ghost nets cause trouble

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.

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Aerial view of the above mentioned haulout in Widewall Bay, South Ronaldsay – © Chris Morris – SMRU

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.

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Bulk of seaweed attached to an old orange buoy with a seagull on top

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Bad news – two dead seal pups due to entanglement with discarded nets

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.

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Extent of the discarded nets, partially buried under the sand © Orkney Marine Services

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Trying to make sense of the nets © Stuart Anderson – SMRU

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.

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Pulling the discarded nets away from the haulout © Orkney Marine Services

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Pulling the discarded nets to the high tide mark © Stuart Anderson – SMRU

Written by Monica

 

Talk at the Orkney Field Club

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Last week I was invited to give a presentation about the harbour seal decline project to the Orkney Field Club. The club is a local charity which focuses on enjoying, understanding, recording and conserving Orkney’s flora and fauna. The club very kindly organized the venue and made sure to spread the word around its members. It was a great evening with a great turn up of over 30 people!

I presented some background information on grey and harbour seals and their current population trends, and then went into the details of the research conducted in Orkney and other areas of Scotland to investigate the decline in harbour seal numbers.

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Presentation at the Orkney Field Club

Showing the movements of the 10 seals that were tagged in back in May was a highlight of the evening, with surprised faces among the audience of how far or close has each seal been moving over the last couple of months.

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Tracks of 10 adult harbour seals over the last two months

We also talked about the use of photo-identification data to estimate birth and survival rates of harbour seals, and how this information is useful to assess the status of populations. We obviously dedicated some time to harbour seal pups, now that we are reaching the peak dates of pupping season in different regions across Scotland.

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Mum and pup pair

After the talk there was an open session of Q&A which was filled with interesting questions about the biology of harbour seals, the monitoring of populations and the potential causes of the observed decline in Orkney and other regions. Overall it was a fantastic evening, and I am very grateful to the Orkney Field Club for allowing me to join them for a seal chat. As the project will continue over the next few years, I am hoping I will have the opportunity to meet again next summer.

Written by Monica