WITNESS: Marine biology at the top of the world

| 12th May 2017
While the warming seas and Atlantic plankton spell trouble for fulmars, they’re great news for the Atlantic cod. These fish, beloved by Brits for our fish and chips, are thriving in the Barents Sea with 80cm to metre-long specimens now commonplace
The return of blue shell mussels to the Artic after a 2,000 year absence, plus the arrival of mackerel are just two signs of a changing climate as JAMES SIMPSON discovers when he joins the scientists and fishermen on a research vessel off the coast of Svalbard
Sometimes the front line in climate change is tiny, delicate and surprisingly beautiful

The Arctic can be a strangely calm place. Standing on deck on a research ship off the coast of Svalbard, the sea is flat like glass. Dark, mist-covered mountains mark the horizon. I watch as a grey-coloured fulmar gull skims past us, its belly reflected in the water. These elegant birds have been our constant companions, hunting for scraps in our wake.

I'm a guest of Knut Sunnanå, chief scientist aboard the Helmer Hansen, a research trawler in the far northern Barents Sea. I've come to see how the Norwegians are managing fishing in the face of some huge changes brought about by climate change. The melting Arctic has opened-up new fishing grounds for Norwegian trawlers. As the cod migrate north, so can the boats.

Norway has some of the world's best fisheries management. It's something that helped the Norwegian cod and haddock fisheries win Marine Stewardship Council (MSC) certification as sustainable and well-managed fisheries. In fact, in MSC assessments, Norway is consistently the highest scoring nation for its management. Standing on the Helmer Hanssen, it's easy to see why.

The ship is a 63m converted prawn trawler, part laboratory and part university. There's even a tiny lecture theatre built into the cramped accommodation deck. The crew is a mixture of fishermen, PhD and Master's students. Each has a different role in finding out about Svalbard's delicate, changing ecosystems and the fish that rely on them.

We are conducting an ocean transect: a series of short mid-water and bottom trawls using small, modified trawl nets, at set points around the Svalbard archipelago. Below decks in the first of three labs, students sort the tiny catch. A dozen large fish are followed by a few dozen smaller ones and a selection of rocks, hermit crabs and starfish. A strange collection of tiny dark ‘blobs' brings interest and for the first time the students fail to identify a species. "It's clearly alive," says Sunnanå, "either a creature or collection of creatures". It's carefully preserved and recorded for identification back on land and there's palpable excitement at finding a species none of them yet know.

A deck above, an even smaller trawl is taking place. "Plankton scientists will tell you their subject isn't sexy like whales and sharks, but it's the most important," says Sunnanå. "Arctic food webs are small, the relationships between species are tight, and plankton underpins everything. You can draw a line with each change having clear consequences for the species that eat it, further up the food chain."

In the plankton sample brought aboard we see sea-angels, beautiful inch-long, semi-transparent creatures that swim up to the glass with wing-like fins.

They're followed by the CTD (Conductivity, Temperature, and Depth), a strange device originally developed by the Woods Hole Oceanographic Institute. It looks more suited to a Mars mission than a mission to the bottom of the sea. My guide points at the screen as the CTD drops 193 metres, to hover a few metres off the seabed. As it sinks, it samples the water, testing salinity, temperature, pH and CO2. These last two are important for our beautiful zooplankton. Too acidic or too much CO2 and these creatures will be in trouble. Sometimes the front line in climate change is tiny, delicate and surprisingly beautiful. 

By testing ocean salinity and temperature Sunnanå's team can also see where the water came from. In this area more often than not, that means the Atlantic. The Gulf Stream used to flow to the west of Svalbard at a rate of 11.5 million tonnes of water every second, but the Arctic is changing. Now the stream splits, running to the east and bathing Svalbard with warm Atlantic waters.

"We're also seeing mackerel for the first time around Svalbard..." says Sunnanå "...and the return of blue shell mussels - a species that hasn't grown here for 2,000 years." And with the warm water come plankton.

The Atlantic plankton moving northwards with the warm water have far less fat than their northern cousins. Three times less. And these diet plankton are a real problem for the seabirds like the fulmars I was admiring earlier from the deck. Low fat plankton means smaller birds and chicks maturing later. In short, fulmars are in trouble.

The water's plankton content is also hugely important for Sunnanå. For him, it provides a measure of the changes happening as well as an indication of how strong the cod stocks will be.

"We are mostly concerned with the fact things are changing and can change very quickly. Although we have a long-term trend that is quite clear, the big changes also take place in just a few years. And on some occasions, there can be a substantial lack of food in the system, probably due to some mismatch during the spring time... or predators."

And there's the irony. Those predators eating Sunnanå's Atlantic plankton include Atlantic cod, increasingly found further and further north. While the warming seas and Atlantic plankton spell trouble for fulmars, they're great news for the Atlantic cod. These fish, beloved by Brits for our fish and chips, are thriving in the Barents Sea with 80cm to metre-long specimens now commonplace.

Good fisheries management is often about having a system to monitor changes and adapt to them quickly to protect stocks, ecosystems and livelihoods. With the rapid, and increasing pace of change in this part of the Arctic, it's of some comfort to see that Norway's science is still driving its decisions.

This Author

James Simpson works for the Marine Stewardship Council in the UK

WITNESS is our new Blog series, which invites contributors to explore the ecological and social impact of issues currently on their radar







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