New Publication – IV oxytocin causes pro-social behaviour in seals

Grey seals on the Isle of May, Scotland. Staying together is important for mother-infant pairs, especially on a dangerous seal colony.

Link to article: http://rspb.royalsocietypublishing.org/content/284/1855/20170554

Or read the summary here on this site.

This week has turned out to be a hectic but good one, I’ve returned from the University of Liege just in time for my next paper to be published in the Proceedings of the Royal Society B. The paper comes from the research in my NERC funded PhD with the Sea Mammal Research Unit, University of St Andrews on the hormone oxytocin and its impacts on social and maternal behaviour, rather than the pollutant research I’m currently doing with the PHATS team. Like much of my work, the study was done with weaned grey seal pups on the Isle of May, and involved giving the seals specially designed doses of oxytocin to see what (if any) social behaviours the hormone affected.

There have been lots of studies that show certain behaviours are linked to oxytocin concentrations (including some of my own grey seal work!), but the problem with correlations is that you have no idea which side of the relationship is driving things. For example, it would be impossible to tell using only correlations whether increased social behaviours are causing high oxytocin levels, or high oxytocin levels are triggering more social behaviours. Understanding causality in such hormone-behaviour relationships is important so you can identify the ‘cause’ and the ‘effect’ within the correlation. It can be difficult to do outside of laboratory settings however, as the only way to test for causality is to either increase the hormone’s concentration in an individual via manipulations or knock out the functionality of the hormone using antagonists. Due to these difficulties, there is only one study (apart from the one I published today) that has ever given oxytocin to wild individuals, and while they did find changes in pro-social behaviours they had no prior knowledge of the natural oxytocin-behaviour systems in their study animals.

We know high oxytocin grey seal mothers stay closer to their pups, but does the hormone cause the behaviour or does being near to their pup for more time cause greater oxytocin release?

In our study we were testing whether oxytocin triggers individuals to stay close to each other, as we know from grey seal mothers that the higher their oxytocin concentrations, the more time they spend close to their pups. We gave oxytocin and saline (control) treatments to weaned grey seals that had never previously met, and recorded their behaviours after the treatments. We found that oxytocin not only triggered individuals that had never met before to spend more time together, but also reduced aggression between the two and the amount the seals investigated each other, an indication of familiarity. This makes our study the first to verify a naturally existing oxytocin-behaviour relationship in wild individuals, which is very exciting. Studies like this have been done in captivity using domestic, laboratory or zoo animals but it’s crucial to study behaviour and physiology in natural settings with wild individuals, as no matter how hard you try you will never truly re-create all the complex aspects of wild environments in a captive setting.

Weaned grey seal pups associating on the Isle of May, Scotland

The treatments were all given intravenously (IV), as the more common, intranasal route of oxytocin manipulation was not possible with the weaned seal pups; they can close their nostrils and hold their breath for a long time! The success of this route of administering the manipulation means that other animal species, that may not be suitable for intranasal manipulations, could potentially have similar studies done on them in the future to help us understand more about oxytocin’s important role in bonding and behaviour. We also spent considerable effort designing the oxytocin dose given to the seals to be as low as possible while still having a behavioural affect. Many doses used in the scientific literature are much higher than natural concentrations, and there are concerns that generating high levels in study individuals could trigger behaviours that would never naturally happen, or have unexpected, and unwanted, side effects.

Weaned grey seal pups having a disagreement on the Isle of May. Reduction of aggression between familiar individuals happens naturally without oxytocin release in seals, but manipulations also trigger this behavioural change with seals that are complete strangers.

Despite the effort we went to in replicating natural oxytocin concentrations as much as possible for our study, the treatments still triggered some behaviours that are not naturally correlated to oxytocin release in seals. Low aggression and reduction of investigative behaviours are indications that seals recognise each other, and naturally occur after several days of living together, independently of oxytocin release. The behavioural changes in our study seals also unexpectedly persisted for several days, long after the dose would have been metabolised and broken down in the bloodstream. These unexpected effects show that we still have a lot to learn about oxytocin’s role in the formation and maintenance of social and parental bonds. If the hormone is going to be used to safely and successfully treat human psychological conditions such as schizophrenia, autism spectrum disorders and post traumatic stress disorder (and there have already been clinical oxytocin trials for such conditions in human subjects), then more research is needed into the powerful effects oxytocin can have on our behaviour and neurobiology.

Weaned grey seal pup on the Isle of May.

Isle of May 2016 – Goodbye to the Island!

dscn4632-sig
A curious weaner watches us load up the boat and leave the island

The time has come for the PHATS team to pack up and go home as almost all the grey seals have left the Isle of May and returned to sea. We have all got back to mainland safe and sound, and everyone is looking forward to some well earned rest after almost two months of fieldwork. All of our laboratory equipment and samples were packed up and shipped off the island without incident, and everything is now at our labs at Abertay University and the Sea Mammal Research Unit, ready for analysis in the new year.

dscn4629-sig
Walking down to meet the boat at sunrise, ready to leave the island yesterday morning

There were only nine of our study weaners still on the island during our last survey, and the majority of them are on the edges of the colony ready to go to sea. Oscar is still hanging out in his pool off the south end of the island, and Papa and X-ray have both made it to the bottom of the southern cliffs and are playing and dozing with a bunch of other weaners there. Hopefully they will all find their way out to sea and learn to forage and catch fish in the coming months. Even if they do survive their risky first year, it’s sadly unlikely that we’ll see them anytime soon on the island again. Grey seals usually don’t come back to breed for at least five years if they are female and even longer if they are male. If they do return to the colony however, we’ll be able to identify them from the number on their orange flipper tags, and if you see any seals with tags please do let us know so we can work out which of our study animals you saw.

dscn4597-sig
Papa (right foreground) with a gang of other weaners, ready to go to sea at the base of the south cliffs on the Isle of May

These kind of mark-recapture methods are used in all sorts of studies on many different animal species, which I was reminded of during the last weaner survey before we left. While searching the southern cliffs I came across a shag with a ring on its leg, which marks it as one of the study individuals the Centre for Ecology and Hydrology has captured, ringed and released back into the wild to help collect data on seabird population dynamics and behaviour. If you see a ringed shag (the leg rings can be several different colours, not just yellow with black writing like the one I saw below) please email the sighting information to shags@ceh.ac.uk and if you are interested in the project’s work then you can keep track of what is happening through their twitter feed @CEHseabirds. This particular bird was ringed as a chick in 2000 on the Isle of May, which makes her 16 years old and she has raised 26 chicks so far in her life (information courtesy of the Centre for Ecology and Hydrology).

dscn4613-sig
The shag I saw on the southern cliffs of the Isle of May, with ‘DDJ’ on her coloured leg band

The PHATS team will be back out in the field in January 2017, when we will return to the Isle of May to look for moulting grey seals. The majority of individuals will enter the moult later in the year at around March/April time, but there are always some seals that start early. We will resume blog updates then, so in the meantime we all wish you Merry Christmas, a Happy New Year and hopefully see you in 2017!

dscn4639-sig
Goodbye for now… grey seals hauled out on the north eastern shore of the island, with the Low Light, the Beacon and the Main Light above them.

Isle of May 2016 – A lover or a fighter? Male mating tactics and the end of the field season is nigh…

Grey seals fighting
Male grey seals fighting for access to females on the Isle of May

Thus far in this blog I’ve mostly focused on talking about the grey seal mothers and pups which live on the breeding colony here on the Isle of May. The PHATS project only involves collecting data from mothers and pups at various ages, hence I’ve somewhat ignored the other occupants of the colony up to now. However, the other individuals on the colony show plenty of interesting behvaiours too, so this particular blog is going to be about the male grey seals that live on the Isle of May at this time of year, waiting to try to compete for opertunities to mate with the females.

dsc_1718a-sig
A male grey seal (right) with two females with pups on the Isle of May. Male grey seals are not significantly larger than the females like in some other pinniped species.

Male mating tactics in species of pinnipeds (seals and sea lions) tend to depend on how sexually dimorphic (differences in size or external features like horns between males and females) the species is and the type of habitat they breed in. Some pinniped species, such as elephant seals, have males that are much larger than the females of their species. This facilitates establishing a territory on a breeding colony that contains as many females within it as possible, defending it from rival males and keeping lots of females inside. These huge males will fight any other males that intrude in the territory to prevent them from entering and mating with the females within. Other pinniped species that breed on ice in the north and south poles of the world use physical features like breathing holes to define where males establish territories, like Weddell seals in Antarctica. Male Weddell seals are a similar size to their female counterparts and use complex vocal displays underwater to defend their territories around breathing holes rather than physically fighting with other males.

dsc_0629a-sig
Some pinniped species are highly sexually dimorphic in terms of body size, this is a male New Zeland fur seal which can be three to five times larger than the females.

Grey seal males show a variety of mating strategies on and around breeding colonies. Males in this species are not much bigger than the females, so creating and guarding large groups of females to mate with (a harem) is not possible. Some males do establish loosely defined territories across various areas of the breeding colonies, but these do not seem to be anchored to physcial features or resources in the colony. The males that compete to stay within the colony amongst the females are called as tenured males and they typically the largest males on the colony, fasting to hold their position in the colony for as long as they physically can before they must return to sea to feed. However, there are alternative mating strategies that males can use to gain opportunities to access receptive females, including intercepting females that are returning to sea when leaving the breeding colony and mating with females at sea. Some male grey seals do return to sea and engage in  shallow and deep diving behaviour during the breeding season, but whether these can be attributed to feeding, displaying to attract mates or aquatic mating with females is not currently know. Therefore there seems to be a variety of mating strategies that individual male grey seals can employ on breeding colonies to gain access to females, and future research will hopefully help us understand which are the most successful and how selection pressures have encouraged the development of the different mating tactics.

dsc_0957a-sig
Being big and winning fights is not the only way for grey seals males to win access to breeding females, but it’s frequently the most conspicuous!
dscn4391a-sig
Delta playing in a tidal pool, the next time the tide comes in he will go out to sea with the receding tide.

The PHATS research project is almost complete as the end of the field season is quickly approaching. We only have two samples left to collect, then we will pack up and head off the island just in time for Christmas! Over half our study weaners have now gone to sea, there are only 13 left on the island. The oldest remaining seal is India at 49 days old, but we still have some fairly young weaners like Eel (not in the phonetic alphabet I know but we always run out of alphabet and have to start giving study weaners name codes like AA, BB, CC… and Eel is EE!) who is only 26 days old and still over 50kg. She could hang around the island for quite a long time with all that blubber mass, we have known weaners to remain on the colony for over a month after weaning.

dscn4497sig
Eel checking me out. She is massive at over 50kg!
dscn4529-sig
Oscar in a tidal pool, meeting other weaners and learning how to swim before the tide comes in and he goes to sea.

Sadly, while doing the daily colony survey to find our study weaners I also found a weaner that had plastic wrapped around his neck. I managed to deprive him of his  ‘necklace’ and he swam off into a pool without serious harm, but it’s a sad reminder of how abundant marine litter is, and how it can cause deadly problems for marine life around our shores. Please be aware of your litter, whether you are on the coast or anywhere outdoors as many speices of creatures can end up trapped or eating the things we throw away, causing severe health problems that they frequently cannot alleviate by themselves.

dscn4406-sig
Marine litter causes significant health problems, and death, for many kinds of marine life from birds, to turtles to marine mammals. Please pick up your trash and dispose of it properly when you are by the sea!

MEANWHILE Away from the colony,we had some visitors for the day this week as some people from Scottish Natural Heritage came out to the island to prepare for the field station closing down for the winter. There are people living on the island almost every month of the year as bird researchers come out in the spring and stay studying the birds until early october, then the seal researchers move in until mid December. However, between December and spring there are a few weeks when no one is living and working at the field station so everything had to be cleaned, packed away and locked up against the winter storms. It was nice to see some new faces after 2 months of seclusion and everyone had a great day despite the choppy sea conditions getting to and from the island!

dscn4520-sig
The SNH guys leaving the island after their visit, hopefully the trip back was drier than the trip out!

The island has also become noticeably more noisy in the last week as the cliffs have become covered in sea birds returning from offshore early to roost. We currently have lots of guillemots

dsc_1675a-sig
Noisy fulmars on the Isle of May cliffs

and fulmars on the cliffs and it is lovely to see some more life on the island, especially now there are so few seals around. With the seals departing, and our project coming to an end this year, we will likely be leaving the island in the next week to head home. Going back to mainland after a few months away from society is always a little strange, but everyone is looking forward to seeing their loved ones (and getting regular showers again!).

dsc_1698a-sig
Fulmar in flight around the cliffs, the strong winds around the island provide excellent opertunities to watch the fulmars soaring around, looking for roosting sites.

Isle of May 2016 – Late season births and Charlie goes to sea!

dsc_1505a-sig
Grey seal mother with her newborn pup on the Isle of May, taken this week.

Even though it’s december and the vast majority of the seals on the Isle of May breeding colony have already raised their pups and returned to the sea, we are still seeing a few newborn pups from mothers that are late season breeders. Most of the colony is quiet now as the majority of adult females have gone, leaving their weaned pups (weaners) in their 2-3 week post-weaning fast (see this blog for more details about the post-weaning fast in seal pups).

dsc_1512a-sig
Things are all quiet now it’s late season, just lots and lots of weaners playing and dozing everywhere!

We don’t really know why some females give birth so late in the season, but doing so tends to have a big impact on how likely they are to raise their pups to weaning, with late season mothers typically having lower pupping success than early season mothers. While there are very few adult females on the colony, and therefore less problems with aggressive neighboring females, there are still plenty of adult males around looking to mate. The ratio of females to males on the colony changes through out the breeding season, and goes from lots of females to every male in the early season to at least one male per female late in the season, if not more. This means that a female trying to raise a pup in the late season has to deal with a lot more male harassment than the females in the early part of the season, and as a result she spends less time nursing and caring for her pup. There is also evidence that females breeding in the late part of the season are younger and therefore are more inexperienced mothers, but what age females start to transition to become early season breeders, if they do at all, is still a mystery, especially as most of our study mothers seem to give birth exactly the same time each year, to the day in some cases.

dsc_1242a-sig
Male harassment can be a big problem for grey seal mothers trying to raise a pup

Back at the PHATS lab, things are starting to wind down. We had to ship all the samples we had generated so far from the cell culture experiments off the island this week as we had filled the minus 80 freezer on the island! The tissue, media and blood samples we’ve collected over the last 6 weeks will give us plenty to study back on the mainland in the new year. Our daily surveys of the study weaners have shown that two of our weaners, Charlie and Alpha, have left the island and gone to sea! Charlie was 35 days old when she left the colony, and Alpha was 43 days old. Some of our study weaners don’t seem very keen to go, both Bravo and Delta are 43 days old and still happily playing around on the island! Some of our seals are making their way through the colony and the rocky tidal region of the shore towards sea, like Foxtrot who is 40 days old and is on the southern edge of the island.

dsc_1643a-sig
Delta playing around in a pool
dsc_1648a-sig
Foxtrot in amongst the rocks of the southern edge of the island
img_1166-sig
Bye everyone!

MEANWHILE the research team on the island has dropped to just 4 people as half the team left the island this week to return home, the remaining two researchers from the Durham University seal behaviour team and two research assistants from the Sea Mammal Research Unit of St Andrews. We also were lucky enought to be visited by one of the bird researchers from the Center for Ecology and Hydrology again, as they keep track of the ringed sea birds (shags) on the island during the winter. During this visit they caught and ringed a wild short-eared owl and were kind enought to show us before they released her, beautiful!

dsc_1564a-sig
Short eared owl that was ringed on the Isle of May, just before release

 

Isle of May 2016 – Go to sea or stay and play? Weaner dilemmas

dscn4114-sig
PHATS team photo! From left to right, Holly Armstrong (research assistant), Dr Kimberley Bennett (team leader) and myself (research fellow) all geared up for an afternoon of studying seals on the Isle of May.

It’s currently my favourite time of year on grey seal breeding colonies, when the  weaned pups (weaners) start to out number the adults on the island. I do enjoy watching the huge variety of behaviour the adults display, from the caring maternal behaviour mothers exhibit to the impressive battles males fight for access to females, but the weaners are without a doubt my favourite. This is because they typically spend several weeks on the island after weaning in a post-weaning fast, where they stay on the breeding colony despite there being no food for them, and they usually spend this time playing and exploring their surroundings. They can be very curious, and some will even come right up to you when you’re hiding in the colony to see what you are, play with youre belongings or even fall asleep on you!

imgp6535-sig
While hiding amongst the stone walled parts of the Isle of May to survey the seals, you can get unexpected visitors at this time of year!

Post weaning fasts are common in Phocid (true seal) seal species around the world, from the huge elephant seals to the two species we get in the UK, grey and harbour seals. No one really knows conclusively why weaners stay on the breeding colony for several weeks after their mothers wean them, although there are lots of theories. Grey seal pups can lose half a kilogram of mass every day they remain on the colony after weaning, and as having large amounts of blubber increases the chances that the pup will survive it’s first year of life, it seems very strange that pups stay on the island rather than go to sea to learn to forage and catch fish. However, there is evidence that during the post weaning fast, pups undergo physiological changes which prepare them for going to sea for the first time, so they can hold their breath and perform deep dives so they can catch fish successfully. In grey seal pups, the amount of oxygen they can store in their blood increases during the post weaning fast due to changes in the volume of blood they have and its components, with increases in substances such as hemoglobin that bind oxygen. The more oxygen a pup can store in it’s blood before it dives, the longer it can hold it’s breath and forage underwater, and in theory the more successful at catching fish it will be.

dsc_1489a-sig
Going to sea and learning to survive there is a crucial step in a weaner’s life, but one with many difficulties and dangers.

There are still many unanswered questions about the post weaning fast phocid seal pups go through and what happens once weaners leave the colony for the first time. To try and answer some of these questions, one of the senior scientists (Dr Sean Twiss of Durham University) here on the Isle of May is currently looking for a PhD student to investigate “Patterns of individual variation in post-weaning behvaiour in wild grey seals“, and the project is being co-supervised by my boss, PHATS team leader Dr Kimberley Bennett of Abertay University! The deadline for applicants is the 20th January 2017, and if you are interested, the details of the project and how to apply are found here. Whoever gets the PhD will get to come out to the Isle of May next year and will meet me and the rest of the PHATS team! Matt Carter of Plymouth University, another PhD student that Dr Bennett co-supervises, is also currently investigating the development of foraging behaviour in pups leaving breeding colonies, so hopefully in the coming years we will gain a much better understanding of the factors driving weaner behaviour before and after they go to sea for the first time.

dsc_1335a-c-sig
Charlie is getting leaner as she loses blubber during her post weaning fast, which has been 17 days long so far, and at 35 days old she may go to sea soon and leave the island.
img_1070-sig
Our CO2 incubator filled with plates of blubber tissue explants for our pollutant work.

In the lab here on the island the PHATS project is just over halfway to completion this year. As it gets later in the breeding season we are getting more and more study weaners to keep an eye on, although some of the first weaners that we included in our study are approaching the time when they may go to sea for the first time, at about a month of age. Charlie is now 35 days old and much leaner than when she first weaned from her mother 17 days ago, having lost 9.6kg across those 17 days. This seems like a lot, but considering she put on 22.2kg of blubber in the 18 days she was with her mother, she is still large enough to successfully go to sea. Kilo has now fully moulted and has a very distinct pattern of spots that we can identify him from. We also have a new study weaner (Oscar) that has moulted and turned out to be completely black!

dsc_1433a-sig
Oscar, one of our latest study weaners.
dsc_1443a-sig
Kilo, now fully moulted with spotty fur, playing with the plant life on the island

MEANWHILE away from the colony, it briefly got a little bit harder to escape from the seals as a female came right up outside our doorstep with her pup for the first time! She has thankfully moved on a little further from the house so we don’t disturb her, but it was a suprise to open the door one morning and find the pair of them staring at us!

img_1061a-sig
Suprise! A grey seal mother has never had a pup right by the house before on the Isle of May

Sadly two members of the research team here have had to leave the island in the last week, Dr Twiss and Dr Bennett both had to return to the mainland to resume their teaching duties at their universities. They will be missed, and it marks the beginning of the end of the field season as the majority of the researchers here will also leave in the coming week. The PHATS team will stick it out until mid December, but it’s always sad to see people go!

Finally if you’d like to see Dr Bennett talking about seals or the PHATS project, she will be giving some public presentations in the coming weeks in Scotland:

6pm, Tuesday the 13th December at the D’Arcy Thompson Zoology museum at Dundee University: Public talk on seal biology

10.00-16.30, Wednesday the 14th December in the Ninth Scottish Symposium on Environmental Analytical Chemistry at the Dalhousie Building, Dundee University: presentation of persistent organic pollutant findings from the PHATS project

dscn4227a-sig
Dr Bennett and Dr Twiss setting off from Altarstanes to return home.

Isle of May 2016 – Pup survival 101: get fat fast, lose your fluff, find some fish

dsc_1337a-sig
PHATS study pups Foxtrot (in the background) and Golf (in the foreground), both at different stages of moulting their white baby fur.

As it gets later into the breeding season here on the Isle of May, more and more of the grey seal mothers are weaning their pups and returning to sea to fish. Grey seals, like most species of true seals (called ‘phocids‘, including all earless seals), have one of the shortest dependant periods (the time the infant has to stay with the mother to survive) of all mammals, just 18 days. After that, mothers leave the colony and it’s up to the pups to look after themselves. Left to their own devices, newly weaned pups (called ‘weaners‘) soon find their way out of the colony or into nooks and crannies out of the way of the adult seals where they can rest and play, moulting their white baby fur (called lanugo) so they are ready to go to sea for the first time.

dsc_0146a-sig
A fully moulted grey seal ‘weaner’ on the Donna Nook breeding colony in Lincolnshire.

Moulting pups are usually much larger than when they were born despite only being 18 days old. Grey seal mothers produce milk with such a high fat content that pups can put on over 1.5kg a day in blubber tissue. Pups that are born at just over 10kg can therefore easily reach over 40kg in mass at weaning, and for seal pups the fatter they are at weaning the better as it means they are more likely to survive their first year of life. During their first year, a weaner’s body composition will dramatically change and they will go from the fat, round shape like in the above photo to a leaner look, like the yearling in the picture below. As a juvenile, a grey seal’s body composition is only about 12% fat of its total mass, a huge difference to the 45% fat individuals can have as weaners. These big changes in body composition are completely natural for the seals, but it means that it is vital for their fat tissue to function correctly both when they are rapidly generating blubber or mobilising it when they don’t have any food. That’s why the PHATS team are investigating whether the high persistent organic pollutant (POPs) burden that all marine mammals have in their blubber tissue is disrupting the seal’s ability to generate and utilise their fat reserves.

dsc_0194a-sig
A lean yearling grey seal on the coast of North Rona, Scotland

We now have 12 study weaners this year, all named after the phonetic alphabet as their identifying code in our project is a single letter. The largest of our pups is Lima, a male weighing 54kg! I introduced you to Charlie in the last blog when she had just weaned from her mother and still had lots of lanugo covering her body, she’s changed a lot in the last week! She’s moulted completely now and has really pale fur with subtle spots.

Charlie now she has fully moulted, these spotty patterns will stay the same on her fur for her entire life.

The other weaners in our study vary from pups that are almost completely covered in lanugo to fully moulted, and its interesting seeing the different patterns the weaners have hiding under their white baby fur. Here are some more introductions to our new study weaners, you can see Foxtrot (female) and Golf (male) in the photo at the top of the blog, and below are pictures of Alpha (male), the oldest pup in our study, and Kilo (male) snuggled up together and Delta (male) playing around with his flippers.

dsc_1350a-ariel-and-kronk-sig
Alpha (left) and Kilo (right) interacting
dsc_1363b-sig
Delta playing around
dsc_1309a-sig
The super moon the night after it was at its largest

MEANWHILE away from the seals, we were all very keen to see the super moon, unfortunately the weather on the island did not co-operate and we didn’t get to see it in it’s full glory. We did all manage to see it before the sun rose the following morning and the next night, which was still very impressive!

pier-underwater-supermoon-sig
The high tides from the super moon submerging the pier at Kirkhaven harbour on the island.

Even though we didn’t get to see the super moon properly, we still felt it’s impact as we had huge tides on the island, and all the seals near the coast found the ocean encroaching where it doesn’t normally reach! The resulted in lots of seal pups getting swimming lessons with worried mothers in tow, and even some underwater nursing attempts.

Sadly it’s getting to the time in the season where some of the team have to think about leaving the island, including our team leader Dr Kimberley Bennett who has to go back to the Abertay University to continue teaching. It’s likely Holly and I will stay on the island until mid December to complete our work on the weaners, so we’ll be getting to know them very well in the coming weeks!

finally-got-milk-sig
A grey seal mother trying to feed her pup during the high tides generated by the super moon

Isle of May 2016 – Beginners guide to pups and meet Charlie!

dsc_1191a-sig
A healthy pup over a week old playing with it’s flippers on the Isle of May

It’s now a very busy time in the breeding season and the island is coverd in grey seals of all ages, from newborns to females over 30 years old. The first weaners (pups who’s mothers have weaned them by going back to sea to eat fish, typically at about 18 days after birth) are starting to appear at the edges of the colony, without their mothers to protect them from aggressive adult seals the weaners quickly retreat to the peripheries of the colony. Even with so many seal pups of different ages around, it is still possible to tell approximately how old a seal pup is just by looking at it. It’s not always easy, but knowing the ages of the seal pups on the island is really important information for the various scientific projects studying the seals. For behaviour and physiology projects, it is crucial to know the developmental stage of a pup you are studying. For population dynamics research (which keeps track of the abundance of speices and detects changes in the numbers of individuals around our coast) knowing how long seal pups are present on a colony helps scientists accurately run models estimating pup production, an important variable in the model representing seal population changes around Scotland.

early-and-late-lactation-sig
The two pups on the right of this picture are clearly very different ages, but by how much? It’s important to know for all sorts of scientific research.

So how do you tell how old a pup is just by looking at it? Here is a crash course! Pups are divided into stages based on their appearence and the stages correspond to approximate ages (described here and drawn here). There are five stages in all, covering newborns to pups that have weaned and are independant from their mothers.

Stage 1.

These pups are the youngest on the colony, and this stage covers pups that are newborn up until about day 5 of life. Things to look out for include a pink, squishy umbilical cord from the pup’s stomach and pronounced shoulders protruding from the pup’s back as they are quite skinny when they are born. The back slopes distinctly away from the shoulders down towards the tail, and sometimes they have dried blood from birth in their fur.

dsc_0183-stage-1-and-2-pups-sig
Comparison of stage 1 and 2 pups, the stage 1 pup on the left has a fresh pink, fleshy umbilical chord from it’s stomach and it’s shoulder blades are clearly visable. The stage 2 pup on the right has a dried up, black umbilical chord and has put on enough fat to stop the bones protruding from its shoulders.

Stage 2.

These pups are between 6 and 9 days old. Their umbilical chord has dried up and if it is still present, it looks withered and black. The pup will have increased it’s blubber layer just under the skin from drinking fat rich milk from it’s mother, so you won’t be able to see the shoulder blades easily any more. The back of the pup will still have a slight slope from the shoulders towards the tail, and there will still be a dip at the neck of the pup.

Stage 3.

Pups within this stage are between 10 and 16 days old and are substantially fatter than the previous two stages. The back of these pups is almost flat because of how much blubber is covering the lower abdomen, and these pups start to look a little like barrels. The dip at the neck will have gone, but the pup will still be entirely covered in white pup fur called lanugo.

dsc_1211a-sig
A stage 3 pup nursing from it’s mother on the Isle of May. The back only starts to slope at the pelvis, not the shoulders as previously in stage 1 and 2.

Stage 4.

These pups can be very distinctive because it is defined by the pup losing (moulting) it’s white fur. As soon as a pup starts to moult the white lanugo, it becomes as stage 4 pup. The pups usually start to moult around their faces and flippers first, then the rest of their body follows over a few days. If the pup rubs against rocks or other seals then the white fur can come out in large patches at one time, revealing the adult fur underneath which is often patterned with spots. These pups are between 17 to 24 days old. At day 18, mothers typically wean their pups so you can see ‘weaners’ with half moulted white coats around the edges of the colony.

dsc_0087-sig
A stage 4 pup that has weaned from it’s mother and is resting at the edges of the colony. You can tell by the white fur on the ground around the pup that it has been in this spot a while! The black and grey fur underneath is the adult fur and the pattern will stay the same for it’s entire life.
dsc_0194-weaner-combo-sig
Three different examples of stage 5 pups, or ‘weaners’. Weaners can be all sorts of variations of grey, black and white including very pale (top), spotty (middle) or very dark (bottom).

Stage 5.

This is the last stage, and includes any pup that is more than 25 days old. These ‘weaners’ have no lanugo left on their body and can vary in colour from very pale, to spotty, to pure black. Weaners often stay on the breeding colony for several weeks after their mothers leave, which is called the post-weaning fast because they don’t have anything to eat while they remain on the colony without their mothers. To get food, they have to go to sea for the first time and learn to catch fish. This means that the amount of fat a pup puts on while it’s with its mother is very important for it’s survival; the fatter a pup is, the more blubber it has to burn for energy and the more time it has at sea to learn to catch fish before it starves. We still don’t really know why pups stay on the colony after weaning for so long as they often lose several kg of blubber during the post-weaning fast.

Being able to tell the age of pups is very important for the PHATS team as we are only interested in pups that are very close to weaning or have weaned from their mothers already (read our blog here for more details about why we sample the seals at these particular times). We have just identified our first study weaner, who is a stage 4 pup that has been dubbed ‘Charlie’ from the phonetic alphabet as her study code is ‘C’. We will be keeping an eye on her for the next two weeks during her post-weaning fast, so stay tuned for updates about her in the coming weeks!

dsc_1215a_c-sig
Introducing ‘Charlie’, our first study weaner! She weaned from her mother several days ago and you can see where she has moulted her white baby fur on her chest and flippers, while her back is still covered in lanugo (making her a stage 4 pup).

In the tissue culture lab on the Isle of May we have received several samples from pups that are about to wean from their mothers and have been successful in keeping the cells alive for the PCB and hormone exposure experiments we are carrying out. To make sure that the cells are alive during the experiments, we sent some of our tissue back to the PHATS laboratory at Abertay University back on mainland Scotland. To do this, Dr James Turton extracted RNA (ribonucleic acid) from the fat tissue in our experiments and determined it’s integrity by putting it on a gel and applying an electrical current to separate out the different sized molecules in the RNA (know as gel electrophoresis). RNA is a vital component of all living cells, it is how DNA (Deoxyribonucleic acid) in the nucleus of cells transfers information to other parts of the cell so it can function normally. If the fat cells died during the experiment, the RNA would degrade and would not show up on the gel. Thankfully our cells were all alive and showed clear white bands of intact RNA on the gel after the test, confirming the RNA has good integrity and the cell in our experiment were alive. Hooray!

james-rna-extracts-10-11-2016-sig
The RNA gel results from Dr James Turton showing clear bands of RNA molecules, which means our cells are alive!

The other research on the island is also progressing well, Dr Sean Twiss from Durham University has been working in collaboration with Dr Patrick Pomeroy from the Sea Mammal Reseach Unit at the University of St Andrews to trial UAVs (unmanned aerial vehicles) for use in seal research. As they fly high over the colony they have the potential to be able to see areas of the island that we otherwise could not study, however the high winds that often blow over the Isle of May can make flying the UAVs difficult! Read more about Dr Twiss’ research on his blog about seal behaviour here.

dscn4032-sig
The UAV flying over the Isle of May between the main light and the beacon.
img_0984-sig
Fresh bread can be tough to come by on an island…
owl-doodle-sig
Owl doodles, guess the species!

MEANWHILE away from the seals, the epic cooking and baking continues! I baked batches of fresh bread rolls for a monster hand-made burger night when it was my turn to cook for the masses. Dr Twiss engineered an incredible sushi evening for dinner over the weekend, almost too pretty to eat! Last night we had a stunning roast leg of lamb, which PHATS team member Holly was in charge of, so good.

Ouside of the kitchen I’ve been amusing myself by working on my sketching skills, doodling various birds that I’ve seen on the island in my sketchpad between all the lab work. Hopefully by next weekend I’ll have a whole menagerie in my book!

sushi-sig
Amazing sushi!

Isle of May 2016 – The PHATS team swings into action

dscn4044-sig
High winds and huge waves are no problem for seals hauled out far from the shore line like these two, but the seals that have pups within the tidal zone can quickly find themselves in trouble.
dscn4025-sig
The once grassy area south of Kirkhaven is now covered in breeding seals
fight-over-new-born-sig
Crowded conditions often leads to more conflict between adjacent seals, this newborn is surrounded by other females and will have to rely on its mother to defend it.
dsc_1083a-sig
Mothers close to the sea may have easy access to water, but if storms hit the island they may lose their pup with the combination of high tides and waves.

Here on the Isle of May the grey seal breeding colony is getting crowded as we approach peak pupping time, which is usually in early November. As the colony fills up with adults and pups, there are more disagreements between neighbours or seals trying to move through the colony, travelling either to their pup or back to sea. So far this year it has been a dry season for the seals, we’ve not had much rain and the pools that are usually scattered throughout the colony have dried up. This unfortunately means that there is much more movement of females around the colony than usual as they try to commute to water sources and then back to their pups. Grey seals typically need access to pools of water, or the sea, regularly to help them cool down. The thick layer of blubber that keeps the seals warm when swimming in the cold north sea for days at a time means they can overheat when constantly out on dry land. In seasons when the weather is dry and pools are scarce, grey seals mothers spend much more time moving about seeking water and less time close to their pups, feeding and protecting them. For the seal’s sakes, I hope that we get a bit of rain soon even if it makes our fieldwork more unpleasent!

For the PHATS team, our project work within the field season is officially starting today. One of the study mothers has now produced a large fat pup who is only one day away from weaning, so last night it was time for research assistant Holly, team leader Dr Kimberley Bennett and myself to get our tissue culture lab ready for the arrival of our first sample. When a blubber sample is taken from a seal for our work we use it in as many ways as possible to get the most information out of the tissue. We run some of the blubber to detect persistent organic pollutants (POPs) contamination in the pup, which is what I was doing over the summer in Belgium with our samples from 2015 (read about that here). The rest of the blubber will be kept warm and well fed with media solutions containing sugars, salts, proteins and fatty acids so that the cells within the tissue stay alive. We can then expose these blubber cells to different experimental treatments of POPs (like polychlorinated biphenyls, PCBs) or hormones that are meant to regulate fat tissue function to explore how hormones control fat mobilisation and how POPs interfere with this process. Tissue culture works involves a lot of lab equpiment that is tricky to ship out to remote research sites, but we have managed to find a small CO2 incubator and UV hood which we can transport out by boat to the island. With a lot of ethanol and lab diligence, we can create sterile conditions for culturing cells out here for the PHATS project, and we’ll spend the next 6 weeks keeping the tissue culture lab running here.

dscn4078-sig
Our little UV hood sterilising after a deep ethanol clean, the UV light destroys bacteria or fungal spores that would love to get into the tissue culture plates and grow where our blubber cells are meant to be.
callan-survey-sig
Callan Duck’s aerial survey plane flying over the grey seal colony

Around the island all the other scietific research projects on both the seals and the birds continue as the season progresses. There are many other projects that are happening at the same time as ours on both the seals and the birds here on the island. Over the last week, Callan Duck from the Sea Mammal Research Unit has conducted an aerial survey of the entire Isle of May colony by plane to perform the annual count of grey seals on the island. Callan will fly over grey seal haul outs all across Scotland throughout the breeding season to monitor the size of seal populations around the country. The bird researchers from the Centre for Ecology and Hydrology are also doing the last mist netting and trapping to catch and ring birds on the island before their research station at the Low Light closes for the winter. They have been kind enough to show us many of the interesting birds they have ringed over the last week, inlcuding waxwings, fieldfares and a long eared owl!

dsc_1134b-sig
Long Eared Owl captured on the Isle of May by the Centre for Ecology and Hydrology for ringing just before release.
img_0956-sig
Happy Birthday time!

MEANWHILE  We’ve had two birthdays in the last week so the PHATS team has been baking! I’ve made birthday cake, Holly helped make 60 profiteroles by hand and Kimberley made an epic beef and ale pie for dinner last night. The team leader here on the island also treats us to pancakes every sunday, so we had a lovely morning yesterday enjoying the biggest stack of pancakes I have ever seen.

img_0971-sig
Pancake time!

Isle of May 2016 – Mothers, pups and battling bulls

dsc_1084a-sig
Kirkhaven beach on the Isle of May, Scotland. Right now the beach (and much of the island’s coastline) is covered in grey seals like these pregnant females, waiting to give birth. You can see a few young white coat pups in amongst the crowd.

We now have a Twitter feed! Please follow us @KJRScience for more photos, news and #IslandLife shenanigans!

The first week of our stay on the Isle of May grey seal breeding colony has flown by, and the number of mother – pup pairs is growing daily. The PHATS team from Abertay University and the Sea Mammal Research Unit, University of St Andrews  is still waiting for our first sampling opportunity before we can start work, looking at persistant organic pollutants (POPs) and how they affect fat tissue function in seals. We will get the chance to start our sample collection in about a week, when the pups are almost ready to wean from their mothers and are large and fat (see the previous blog for more details about our sampling regime). While we wait both Holly and I are helping survey the colony regularly by doing observations of the seals arriving and looking to see if any seals are study individuals. Study individuals are females that have been included in the Isle of May grey seal research project for many years, and they usually have small flipper tags to help us identify them. Female grey seals typically come back to the same colony to give birth, and as they have spotty patterns on their fur that stay the same throughout their lives, we can identify the same females year after year and build up long term datasets of what happened to them across many years.

dsc_1105-sig
A pregnant female grey seal on the Isle of May. She clearly has a orange flipper tag in her right flipper, making her a study individual. If you see a seal with a flipper tag, or find one on a beach please let us know! All the spots on her fur stay the same throughout her life and we can use them to identify her.
dscn4000-sig
Taking pictures of study individuals at one of our hide locations above Kirkhaven beach on the Isle of May

All the other research projects on the Isle of May are in full swing, as they are interested in the seals from when the pups are born right through to weaning. For example, Dr Sean Twiss is leading a team here from Durham University studying the maternal behaviour of grey seals and how it can be linked to physiological metrics like heart rate data from novel, external loggers they designed and built themselves (read more about their research here). There is always plenty going on to observe in the colony, never a dull moment! Here are a few of the behaviours you can see currently on the Isle of May breeding colony:

Births

Grey seal birth
Grey seal birth on the Isle of May
dsc_0864a-sig
Birth can be a bloody business, but it does help us spot newborns on the colony!

Grey seal births are extremely rapid and can be tricky to see. After the birth, mothers will sniff their pup and bond with it so they can stay together for the coming weeks on the busy colony. Newborn pups are pretty easy to spot as the mothers can be quite red from the blood lost during delivery and sea gulls come to scavenge the placenta to eat. Seal mothers do not always react well to this, and can spend lots of time chasing gulls away from themselves, their pup and the placenta. My PhD work was primarily on maternal behaviour and how mother-pup bonds form, and I always love watching births if I can spot one.

dsc_1080a-sig
Sea gulls like this young Black backed gull will steal the placenta to eat if grey seal mothers let them

Nursing

Grey seal mothers only spend about 18 days with their pups before weaning them and going back to sea. In those 18 days it is vital for the pup to drink as much fat rich milk from the mother as possible, the larger a pup is at weaning the more likely it is to survive its first year of life. Grey seal milk is 60% fat so pups can put on weight very quickly, pups born at 18kg can easily reach more than 50kg in just over two weeks! Nursing bouts take about five minutes and happen approximately ever four hours throughout the day and night.

dsc_0380a-sig
A week old grey seal pup nursing from its mother on the Isle of May

Defending the pup from other seals and gulls

A grey seal mother will aggressively defend her pup from anything that approaches too closely. Other female seals will attack any pup that is not their own and males will not tolerate pups in their personal space either. Without their mothers to defend them, pups soon become covered in bites from other adults. Sea gulls can also seriously injure, and in some cases kill, grey seal pups by pecking at their eyes and fresh umbilical. Mothers therefore do not tolerate gulls coming to close and will aggressively chase them away.

dsc_0948a-sig
Two grey seal mothers fighting to protect their pups. Mothers are frequently surrounded by other mother-pup pairs on the colony and disputes between neighbours happen a lot.

Male dominance fights

As the breeding season progresses, more male grey seals arrive on the colony to try and hold a position among the females, so that they can try to mate with them once the pups are raised. Males will threaten each other with hisses and open mouth threat displays, but many confrontations do not result in fights as these are dangerous and tiring for both parties. Sometimes however, neither male will back down and the two will fight brutal battles for dominance, biting and shaking each other’s necks and heads.

dsc_0957a-sig
Two male grey seals fighting for access to females on the Isle of May. The necks of adult makes are often covered in scars from these battles.
dscn3997-sig
mmmm cupcakes…

MEANWHILE away from the seals, the team on the Isle of May are enjoying island life as much as possible. The sunrises here are stunning and there are lots of amazing birds flying around to watch out for, the short eared owls are a particular favourite currently. Half of the team indulged in a rare TV night to join the rest of the nation in watching the Great British

img_0949-sig
Happy Halloween everyone!

Bake Off final, and as that put me in a baking mood I made some coffee and walnut cupcakes for everyone. We were joined yesterday by the leader of the PHATS team, Dr Kimberley Bennett fresh from teaching at Abertay University and she brought some  fresh food supplies, even more lab gear and halloween goodies! Cue some epic pumpkin carving by Holly and fellow research assistant Izzy, now to put them somewhere high so the mice don’t attack them in the night!

dsc_0852a-sig
Sunrise over Kirkhaven on the Isle of May, from our kitchen window!

Isle of May 2016 – Out to the island

dscn3883-sig
Grey seals watch us arrive at Kirkhaven on the Isle of May at dawn on the May Princess to put all our laboratory and food supplies for the next 8 weeks on the island.

The end of October means only one thing for the PHATS team, it’s time for our winter field season on the Isle of May, Scotland. Every year from late October to mid December, thousands of grey seals arrive on the island to give birth to their pups and breed, and this gives us scientists at the Sea Mammal Research Unit (SMRU) and at Abertay University the chance to study all kinds of things about the seals, from their behaviour to immunology. Every year we are joined by researchers from other institutions across Europe, such as Durham University’s behavioural team (read more about their research here) and we also collect samples for collaborators to analyse back on the mainland. The PHATS team is specifically interested in the physiology of grey seal blubber and how it is affected by persistent organic pollutants (POPs), so we will be heading out to collect blubber samples from the seals to continue investigating how these chemicals impact on fat tissue function.

The last few weeks have been a blur of preparing all the lab gear we need for the 8 week field season and packing it securely for crossing to the island by boat. Running a remote tissue culture lab involves a lot of supplies, as everything from CO2 incubators to tiny sample tubes to liquid nitrogen has to be taken to the island so we have it to hand when we collect samples from the seals on the colony. We have so much large, delicate equipment and boxes full of supplies that every year we have to wait for a ‘weather window’ to take everything out on a large boat, the May Princess. This is the boat that usually takes visitors to the island in the summer (if you’d like to visit the island, their website is here, there are lots of sea birds like puffins to see at that time of year!) and it can carry far more gear than the smaller, faster RIBs (rigid-hulled inflatable boat) that take us to and from the island during the winter. It’s not only the lab equipment that gets taken out when we take this bigger boat to the island though. We need to take enough food to last the 8 week field season on the Isle of May too, so the night before our chance to take the Princess out to the island we did some monster food shops!

img_0921-sig
Some of the PHATS lab gear packed, ready to ship to the island. The PCR hood is made of glass so is especially fragile!
img_0923-sig
Frantic food shopping as the sun goes down the day before our Princess trip to supply the island.

This year, the only day that looked calm enough to take the Princess out had high tides very early in the morning, so we left the harbour at 5am in the dark. There were several seals watching us arrive in the harbour at Kirkhaven on the Isle of May, and even a few mothers and pups on the surrounding rocks. In the coming weeks, Kirkhaven will completely fill up with mothers and their pups as it’s a major breeding site on the island. This makes landing large amounts of equipment later in the season impossible without causing lots of disturbance to the colony, which we want to avoid at all costs.

dsc_0281-sig
A grey seal mother with a young pup, only a few days old. Kirkhaven and the coastal parts of the island will soon be full of mother pup pairs like this.

After some frantic unpacking about half of the team, including myself, headed back to mainland on the Princess while the other half stayed on the island to observe the colony while the seals are arriving. The rest of us headed back out four days later on the RIB to join them to start the fieldwork, and we were lucky enough to have a beautiful blue sky day to take the RIB out to the island. The PHATS team leader, Dr Kimberley Bennett from Abertay University, was with us for the dawn supply run and she will be coming out in November to join in the fieldwork fun. I have a new research assistant to help me this year with all the sample collection and lab work; Holly Armstrong. She is Dr Bennett’s PhD student and is writing up her thesis on cellular stress physiology in grey seal blubber tissue, so she has lots of experience on the island working with the seals and tricky tissue samples!

dscn3899-sig
The PHATS team leader, Dr Kimberley Bennettwith the Isle of May in the backround on the return trip of the supply run. She’ll be back to the island soon!

While we are on the island, the PHATS team is hoping to collect blubber samples from 30 grey seal pups at two time points in the field season:

  1. The first sampling time point is when the pups are big and fat, just before they wean from their mothers. This sample lets us investigate how fat tissue functions when the seals are generating fat reserves, as they are still nursing and drinking the fat rich milk their mothers produce. If POPs are disrupting the pup’s ability to store fat, these samples will allow us to detect this effect.
ninjar-dsc_0107-sig
A mother with a pup that is close to weaning (photo from previous years fieldwork). Grey seal pups can put on more than 20kg of blubber tissue in just over 2 weeks.
  1. The second sampling time point is when the pups are weaned from their mothers, during the 2-4 weeks they stay on the colony resting before going to sea for the first time. They do not feed during these weeks, so this sample lets us investigate how fat tissue functions when the seals need to utilise their fat reserves. If POPs are disrupting the pup’s ability to access stored fat, then these samples will allow us to detect this effect.
dsc_0142-sig
A weaned pup on the Isle of May (photo from previous years fieldwork). Once weaned the pups shed their baby coats of white fur.

As POPs are considered obesogens (which are chemicals that prevent the fat tissue from responding to your body’s signals), we are especially interested in investigating the  physiological differences we see across the two samples, which is why it is important to sample to same individual twice in one season.

In order to investigate the affect POPs have on fat tissue, Dr Bennett developed a novel technique which allows us to get the most information possible out of small tissue samples. By keeping the fat cells in the blubber sample warm and in specially prepared buffer solutions after sampling, we can use cell culture approaches to keep the fat cells alive for days. This allows us to split the sample into smaller pieces (called explants) which can then be used for lots of different experiments and analysis. By using this approach we can actually expose fat cells from the seals to elevated POP concentrations to see how the cells respond without subjecting the individual seal to those pollutants. This experimental approach means that we can detect causality (what is causing things to happen) rather than simply detecting correlations (what things are linked to each other).

But before any sampling for the PHATS project can take place, the grey seal mothers must arrive, have their pups and raise them successfully so they are big and fat. This gives the PHATS team about two weeks to get the lab set up and perfect our protocols before our first samples are collected and arrive in our field lab on the island. In the meantime, there is plenty happening here with all the other research that is going on at the same time as our project, and of course there is always interesting things happening in the seal colony. Now we’re on the island I’ll update this blog every week with what is going on here in the field, and hopefully in a few weeks time I will get to introduce you to our study animals! In the mean time, I better think about what I’m cooking for dinner for all eleven of the Isle of May team…

dscn3936-sig
Heading out to the Isle of May in the RIB yesterday, nice weather for a change!