Isle of May 2016 – Out to the island

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!

Some of the PHATS lab gear packed, ready to ship to the island. The PCR hood is made of glass so is especially fragile!
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.

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!

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.
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.
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…

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

New Publication – Individual aggression in young grey seals

Working out whether to be nasty or nice to your neighbors is crucial for many species!

Link to article:

Or read the summary here on this site.

Its that time of year when lots of people at my lab in St Andrews are getting ready for the grey seal breeding season on the Isle of May (IOM16), an important chance for many different projects studying everything from behaviour to physiology to get crucial data or samples. Logistically, getting all the supplies for the science the PHATS team needs to do in the next two months is quite a challenge and I’m currently packing and checking equipment off all sorts of lists to ensure we’ve got everything. Everything for the tissue culture work needs to be sterilised here on the mainland and packaged up carefully so we can get it out to the island in one piece, taking PCR hoods and incubators out on boats can be interesting but we managed fine last year so I’m sure it will all work this year too. We should be heading out to the island in the last week of October (as long as the weather plays ball), and I’ll start posting regular blog updates about what’s happening once we are in the field.

In amongst the ‘organised chaos’ of all the packing, it was great to see that one of my new papers was finally available online for people to read. The work was done as part of my PhD and happened on the Isle of May too, although this study was a purely behavioural one. Its always a relief to get a piece of work published, the process can be long and arduous but ultimately getting your science out there for other people to read is what research is all about. So why study aggression, and why on the seals on the Isle of May? Read on…

Aggression is a vital aspect of an individual’s behaviour in the majority of animal species trying to live in the wild. Being aggressive enables individuals to take things from others that they need to survive or reproduce, such as mates, good quality habitat to live in or things to eat and drink. Conversely, being aggressive also means you can defend yourself, your offspring or members of your social group from attack, or protect your territory or food resources from attack. The ability to gain the best resources to live on, and keep hold of them so you and your offspring benefit from them, is therefore an important one. But as aggression can have high negative costs, such as injury or even death, striking the balance between individuals that aren’t push overs, but don’t get into too much conflict is an interesting evolutionary challenge all species face. There is huge variation in how aggressive different individuals are, and while some of this variation can be attributed to true psychological differences, which only exist in each individual’s head, we wanted to know to what extent physiological or environmental factors impacted on how aggressive individuals are.

Aggression can enable individuals to protect things that are valuable to them, like their offspring…. (grey seal mothers and pups on the Isle of May, 2015)
…or aggression can help you fight for the things you need, like access to the lady seals! (male grey seals fighting for access to females, Isle of May, 2011)

There have been many studies on the sources of individual aggression in a variety of species, from humans to insects. However there are not many studies investigating how aggressiveness in individuals develops in the wild (the ontogeny of a trait). As I had previously designed and carried out research documenting aggressive behaviour in the weaned grey seal pups on the Isle of May, it was an ideal place to try and find out more about the individual factors that influence how aggressive individuals are towards each other. We found that pups raised on crowded areas of the colony were more aggressive than pups from areas with few seals, and that physical characteristics (sex and size) also influence how aggressive individuals were. Males got more aggressive the bigger they were, but female size and aggression showed a non-linear relationship, meaning even a small female seal could still be very aggressive towards others!

The social environment you are raised in has been shown to have lifelong impacts on your behaviour, so it would be great to determine whether these aggressive pups from high density areas of the breeding colony stayed that way throughout their entire lives, or whether other factors take over as the individual grows up. The same is true for males and their body size, are these males only aggressive when they are large, and do they become more timid as they lose mass when using up their fat reserves during the moult or breeding season? Lots of questions still to answer, but this study highlights how a few individual features can influence behaviour, and indicates these variables are worth investigating in future work.