Svalbard Blue mussels on the menu?
Top image: Blue mussels in Svalbard waters. Photo: Peter Leopold.
The first blue mussels discovered in Svalbard in modern times turned up in 2004. Blue mussels have been able to live so far north in prehistoric times, when the climate was much warmer than today. With the gradually warming Arctic of present day, it was no surprise that mussels were found a decade ago. The blue mussel is thus a valuable modern climate indicator for Svalbard and the Arctic.
24 October 2014
Text: Professor Jørgen Berge, University of Tromsø and UNIS. Photos: Peter Leopold
Back in 2004, my colleague Geir Johnsen and I were diving in Isfjorden when Johnsen found the first blue mussel. Johnsen swam over to me and showed me this mussel with much anticipation. At first I thought, “So what”, but after a minute it really dawned on me what we had actually found – the first evidence of a living blue mussel in Svalbard in about 1000 years! It was two euphoric scientists that went ashore with this spectacular “catch”.
I can therefore understand how PhD candidate Peter Leopold felt when he dived in Adventfjorden close to Longyearbyen a few weeks ago, and found a large “carpet” of young, fresh blue mussels, almost to the day 10 years after our blue mussel discovery further out in Isfjorden.
For the past 10 years we have investigated scattered deposits of blue mussels and written several articles about it.
We have investigated larger areas along the western coast of Svalbard and documented where these mussels are present or not, which is equally important, and we have also studied their growth and development in relation to their habitat.
We have even used Rijpfjorden (a fjord on the northern side of Nordaustlandet) as a cold climate laboratory in order to study the mussels’ tolerance for a high Arctic climate.
In this respect, Rijpfjorden is a very interesting habitat, as it is the world’s northernmost area where fossils of blue mussels are found, indicating that this is the northern limit for the mussels’ dispersal.
However, we have always been confronted by the question: Why is this interesting? Isn’t the rediscovery of blue mussels in Svalbard just a result from the many cruise and cargo ships coming from the south bringing with them larvae and small mussels?
We believe that ship traffic is not a realistic explanation for the reintroduction of blue mussels in Svalbard, especially since there are no reported finds of blue mussels until a decade ago – and Svalbard has had a lot of ship arrivals also prior to 2004.
But even so, why is it we have not yet found the characteristic “carpets” of young mussels along beaches, on the quays and underneath boats, as is normal further south? Isn’t the lack of these carpets a strong indication that blue mussels in Svalbard is artificially introduced by human activities?
Peter Leopold, a PhD student at the University of Tromsø and UNIS, is studying the occurrence and the biology of the Svalbard blue mussel (growth, age, fertility, etc.). The plan was for Peter to collect a number of blue mussels in order to perform an experiment here in Longyearbyen.
A few weeks back, Peter went out to collect mussels – and we got two major surprises:
1) We suspected we would find blue mussels on the quay constructions here in Longyearbyen, however we were just totally unaware of the sheer number of mussels we would find (see photo below).
The density of blue mussels was much greater than we had ever seen anywhere else in Svalbard. On the one hand, this is good news for us, but on the other it might indicate that the ship traffic is indeed the source for the amount of blue mussels? If these mussels are the result of ship traffic, it is not scientifically interesting for us to do research on them, as we aim to study the natural dispersal.
2) Peter also went swimming in the nearby harbor area and found a large carpet of small blue mussels on one of the local boats. Almost all of these were yearlings, i.e. developed from the larvae stage this season – something we have never observed in Svalbard before!
The question immediately presenting itself is this: Were these blue mussels a result from mussels attaching themselves to the boat while it was visiting mainland Norway, where this is a common occurrence? However, after a quick chat with the owners of the boat, it was confirmed that this boat had only been in Svalbard over the past year!
This is proof of two important things:
a) Blue mussels are reproducing locally in Svalbard – and
b) if these mussels are not a result from ship traffic and since blue mussels have been a “local” species in Svalbard a few thousand years ago, the conclusion must be that blue mussels is indeed a natural phenomenon in Svalbard!
Thus, Peter’s research the next 3–4 years will have a great relevance for our understanding about how the climate affects the natural dispersal of blue mussels and other marine species.
This story will be updated in the years to come. In the meantime, maybe it is time to start thinking about putting true Svalbard blue mussels on the menu? In that case, bon appetite!
This work is funded by the Research Council of Norway through the project Marine Night, University of Tromsø and the Fram Centre through the flagship programme Fjord and Coast (“Life on the edge – blue mussels on Svalbard”).