Research

Population genomics of Antarctic and sub-Antarctic penguins

During my PhD I used comparative analyses among five species of penguin to reveal barriers to dispersal. My research, using samples from 32 colonies covering five species, showed that at-sea range (that is, how far the penguins tend to travel out to sea) during the non-breeding season seems to be the best determinant of gene flow. In species that go a long way, we see very low levels of differentiation among colonies. Species that are residents at or near their colonies year-round, showed very high levels of differentiation among colonies. We also found an effect of the Polar Front in limiting dispersal in king and gentoo penguins.

I also studied the effect that climate change throughout the Holocene had on penguins, from the high Antarctic to temperate latitudes. To do this, I reconstructed historical population sizes for multiple species and populations, using both ancient and modern DNA. I then correlated these changes in population size with paleoclimatic conditions, to show how periods of past climate change affected penguin populations.

Adelie penguins against a beautiful backdrop of blue ice on Patella Island, northern Antarctic Peninsula. December 2015.
Christmas day with king penguins at Gold Harbour, South Georgia. Life doesn’t get much better! December, 2014.
Gentoo penguins on a hot day at Neko Harbour, December 2013.
Chinstrap penguins looking goofy on Deception Island, November 2016.

 

Adaptive genetic diversity of Atlantic cod in the Gulf of Maine

Atlantic cod make up one of the most culturally and economically important fisheries in the North Atlantic. Currently, populations in the Gulf of Maine are at a fraction of their carrying capacity and fishing quotas have been drastically cut to promote recovery.

As part of an interdisciplinary research collaboration between scientists, fishermen, and fisheries managers, I am assessing the biological structure of the remaining stocks. I am using RADseq and ultra-low coverage whole genome data to study adaptive differentiation among the multiple sub-populations and spawning groups. This has proved to be a fascinating species to study as there’s a whole lot going on in their genomes!

Atlantic cod. Photo credit: Joachim Muller.
We are sequencing whole genomes from DNA extracted from these ancient otoliths to study the genetic diversity of spawning groups that have now been lost.

 

Studying seabird diets using metabarcoding (aka getting pooped on by seabirds for science)

Seabirds are fantastic fisheries biologists. Every day during the breeding season they go out and sample the local marine environment and so, by monitoring what they’re eating, we can learn a huge amount about local fish populations. We hope that monitoring their diets will also tell us why some seabird populations are doing relatively well, while others are in trouble.

I’m developing fecal DNA metabarcoding methods to identify the fish and other prey that they’ve been eating. This involves collecting poop samples and then sequencing all the DNA in there to identify which critters it came from.

Through a collaboration with Jennifer Seavey and Elizabeth Craig at the Shoals Marine Laboratory, I’m assessing the diets of threatened and endangered terns breeding on the beautiful Isles of Shoals. The islands are a couple of miles off the New Hampshire coastline and represent the state’s only breeding colony of common, roseate and arctic terns.

A roseate tern on the Isles of Shoals, NH, 2017.

 

I’m also working with Annette Fayet from the University of Oxford to study the diets of Atlantic puffins in the UK, Iceland, and Norway. Some colonies of puffins seem to be doing relatively well, while others have declined dramatically, and we think this is due to a shortage of sand eels. We’ll be using fecal DNA methods to monitor the diets of adult puffins and combining this with tracking data to see where they’ve gone and what they’ve eaten.

An Atlantic puffin, Skomer Island, Wales 2016.

 

 

 

 

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