In 2015, the red-listing of puffin as vulnerable to global extinction rang alarm bells for everyone interested in the health of our oceans, writes Euan Dunn, RSPB Principal Policy Officer.

In response to that challenge, seabird, plankton and fisheries experts will gather this week in Reykjavik. Along with oceanographers from Europe, the USA and Canada, the biologists will explore the causes behind eye-watering rates of population decline in puffins and other North Atlantic seabirds.

The workshop organised by the RSPB and Fuglavernd (BirdLife in Iceland), and hosted by the University of Iceland, will work out what collaborative action they can take to predict future scenarios and recommend next steps to lessen impact of the most dramatic transformation of our marine environment witnessed since records began. Iceland was chosen as the venue to highlight that the Nordic countries are experiencing particularly severe losses in their seabird communities.

What is abundantly clear is that the North Atlantic is undergoing fundamental change and environmental pressure. Evidence is mounting that climate change – and particularly sea warming – is disrupting the entire food web from plankton through small shoaling fish to the puffins, kittiwakes and other seabirds which depend on them for survival and successful breeding.

Breeding puffins (c) Alec Taylor

Warmer-water plankton species are expanding northwards in the North Atlantic at a rate of around 23km per year, replacing the cold water plankton which have dominated the North Atlantic and propped up the marine food web since the last Ice Age.

The overall abundance of zooplankton is declining, by as much as 70% in the North Sea in the last fifty years, an upheaval so dramatic as to be termed a ‘regime shift’ by oceanographers. Associated with this, small fish called sandeels which used to shoal in enormous numbers are disappearing from northern coastal waters, depriving many seabirds of their staple diet and causing chicks to starve.

From Shetland to Norway, the Faroes and Iceland, these changes are being linked with widespread breeding failure and seabird declines. In the Westman Islands, once the Icelandic stronghold of the puffin’s global range, chick production has collapsed for well over a decade, resulted in a population decline of over 40% since 2003, equivalent to nearly 2 million breeding pairs lost, according to local puffin expert Erpur Snær Hansen. These birds haven’t gone elsewhere, they simply don’t exist.

Puffins and other seabirds on the eastern seaboard of North America are also suffering chronic food shortages, with birds having to resort to less suitable prey in efforts to raise their starving chicks. All of this strongly suggests that common underlying factors are radically altering the marine environment across the entire breadth of the North Atlantic.

While seabirds as top predators are the most obvious indicators of this disruption, the recovery and northward spread of mackerel (which prey on sandeels and other small fish) are also part of the story, benefiting commercial fish catches but adding to the competitive pressure on seabirds and other top predators to find enough food for themselves and their young.

Puffins (and other seabirds) rely on the oil-rich sandeels as an integral part of their diet (c) Neil Longhurst

It has become clear that a major collaborative effort was needed to advance our understanding and to predict the future fate of these threatened seabird populations and other marine wildlife. For example, will the current rate of sea warming and seabird decline continue relentlessly or will the long-term cycle of major North Atlantic Ocean currents come to the rescue and create cooler, more benign conditions before seabird populations are decimated?

It is hoped that the workshop will be a first step in creating a cross-disciplinary network of practitioners who can combine their skills and research findings to help unravel cause and effect, and build the bigger picture. In recognition of the North Atlantic dimension of the problem, seabird biologists from Maine to Newfoundland will join their Nordic and other European colleagues in this unique collaboration.