An American Lobster in Stockholm

In 2010 a researcher found a clutch of hybrid American-European lobster eggs in a Norwegian fjord. This kicked off a decade of research in attempt to determine if Scandinavia was in the midst of a foreign lobster invasion. This question is hard to answer, especially when the fate of a business worth $150 million dollars a year hangs in the balance.

When you’re a lobster expert,  it’s just a totally normal part of the job that people bring you all sorts of weird-looking lobsters.

“It’s usually just leisure fisherman or commercial fishermen that say, ‘ooooh, this is a funny-looking lobster — odd-looking lobster... what can this be?’” explains Ann-Lisbeth Agnalt, a researcher at Norwegian Institute for Marine Research. This is something that happens to American researchers too, but up in Norway, fishers typically bring Ann-Lisbeth really purple lobsters, which is a color that large, female, European lobsters take on when they have been living very far from shore. And so usually she just reassured them that this is a normal thing to see.

But in 1999 she got something different.

European Lobsters are typically black with perhaps a bit of blue. But this lobster was more reddish or greenish. Immediately Ann-Lisbeth was worried and sent in for a DNA test. When the test came back, it confirmed what she had suspected: this was an American lobster. The concern was that these lobsters might actually out-compete, out-perform, and out-survive their dark-shelled European cousins, or even breed with Europeans, but produce sterile offspring.

At first, she and other Scandinavian scientists were worried, but not necessarily freaked out. One rogue lobster didn’t really prove much of anything. But over the years, more American lobsters started turning up. It took a decade to get to full freak out stage.

In 2010, another lobster came in through the door. This one had eggs that she had extruded out onto her tail, which is what lobsters do when their eggs are fertilized. Immediately she checked the eggs and determined that she had been handed something she was afraid of, but thought it was really unlikely she would ever be lucky enough to find… a female American lobster with eggs that had been fertilized by a European lobster. She had found a clutch of hybrids.  


The Swedes Mount Their Case

Ann-Lisbeth hatched those hybrid eggs and came up with 10,500 lobster larvae. Of all those thousands, 65 are still alive and are creeping their way towards maturity. So far, she has been testing the males’ sperm counts, but her results are inconclusive. They aren’t producing much sperm. It might be that even seven years after being born, they still aren’t quite mature, or it could be that they’re actually sterile.

Either way, the Scandinavians argue it’s bad news for local lobster populations. “Worst case scenario is we lose lobster production, completely. That’s the worst case scenario,” says Susanne Eriksson, a Swedish Scientist with the University of Gothenburg, who is rearing another clutch of hybrid lobsters. Since the first hybrids materialized, two more females with mixed eggs have been found.

But then, starting in 2014, American lobsters started showing up in traps more consistently, and the Scandinavians got serious about this threat.  It was the Swedes that got the ball rolling. They wrote a report that concluded that American lobster was a high risk species, and that imports should be banned.


Most lobsters arriving in Europe are shipped in the belly of passenger airline flights, bundled in boxes lined with ice packs and moist “thirsty pads.” They can survive flights up to forty hours in these boxes. This is particularly true if you’re headed to Dubai, and Emirates actually increased the number of flights between Boston and the UAE to accommodate the lobster shipments.

The lobsters leave this facility in boxes, on pallets, wrapped in shrink wrap, and then wrapped in special TSA tape that ensures they haven’t been tampered with. They can’t get out on their own, so clearly, the lobsters are escaping once they get to Europe.

How? It might be that after buying them, some people are putting them into illegal floating cages out in the ocean to keep them fresh and they escape from those. There have also been a couple of high profile instances of Buddhists or animal rights activists buying hundreds of American lobsters and releasing them as an act of compassion, only to get fined afterward.

“Stupid people,” Ann-Lisbeth calls them, “Either they release them on purpose or they release them by chance, they think they are dead and then they are not, or if they keep them in some kind of containers in the ocean, and then there’s a hole in this container and they escape. I mean, there are a whole bunch of scenarios.”

Invasive Vs. Non-native

Let’s just reflect for a moment on two words: non-native and invasive. I think a lot of people probably have a negative association with both words, but I’d also be willing to go a step further and say that a lot of people actually conflate the two words. And that’s a mistake. For instance, tomatoes: non-native but also definitely not invasive. On the other hand: ivy or wisteria or bittersweet or any number of other once common garden plants are horribly invasive.

“As a matter of fact, the vast majority of non-native introductions do not succeed,” says Bob Steneck,  a lobster researcher at the University of Maine.

In other words, for every invasive bug or fish, there are tons of animals that just can’t hack it in a new environment. Just as an example, maybe you’ve heard about the scourge of invasive zebra mussels, which came over from Europe in the ballast water of ships. The total cost of the Zebra mussel invasion is estimated to be $3.1 billion dollars over 10 years.

Hearing that might lead you to believe that ballast water is just teaming with foreign invaders, ready to explode into our waters, but a study that looked at ballast water identified 10,000 species in ballast water. One or two possibly could be invasive.

The point here is not that invasive species are no big deal, because they are. It’s just that we have a really hard time knowing what’s going to be an invasive species before the invasion actually begins, and assuming that every non-native bug or plant or crustacean is going to be a plague with massive impacts on ecosystems… just… isn’t… correct...

The Americans Respond

When she first heard about the idea of a European ban on live lobster imports Annie Tselikis, president of the Maine Lobster Dealers association, thought “You’ve got to be kidding me.” Twenty percent of American lobster exports go to Europe, so suddenly — because of “stupid people” — the industry was looking at losing  $150 million dollars of exports a year overnight.


And the Americans flat out rejected the idea that this was an invasive species. “When you think about invasive species they’re typically ones that reproduce really quickly and efficiently, and lobsters are the antithesis of that,” says Annie.

In response to the Swede’s risk assessment, they called out the cavalry. One of the scientists who they asked to give feedback was Bob Steneck. “I am hawkish about the language we use,” he says. “A non-native species has been found in those waters. This has not been demonstrated to meet even the minimum criteria of being invasive.”

Back in the early 1900s, Bob says people saw the prospects of an American lobster invasion very differently. The thinking back then was “this is an amazing species, and we should be striving to propagate it all over the world,” he says, and entrepreneurial Americans set about trying to make this happen. Commercial lobster aquaculture operations sprouted up in British Columbia, Bodega Bay California, France, Italy and Japan. Hundreds were also released accidentally in Ireland, just around the corner from the Scandinavian waters that are currently of concern. And every time, American lobsters failed to get themselves established.

“It was really kind of surprising that a species that is so abundant in the Western North Atlantic, and on our coast, seemed incapable of self-reproduction outside of its native range,” says Bob. He says so far, around 100 American lobsters have been caught in Europe over 10 years, which does not amount to an invasion. It’s expert testimony like this  that the fishing industry gathered to make their case: Maine’s whole congressional delegation signed a letter saying there’s no way the lobster is invasive, the State Department got involved, and Canadian fishing regulators wrote in supporting the American position.

The Swedes Aren’t Buying It.

“They are clearly reproducing in our waters,” says Susanne Eriksson.

She says that just because lobsters haven’t thrived and taken over in other places at other times, doesn’t mean it won’t happen in the future. Sure, in the past Americans haven’t gotten a foothold, but things are different now. Now, Europe’s lobster population has crashed in some places. Now, global trade might mean there are hundreds even thousands being released each year… we just don’t know.

“And remember that every female she carries tens of thousands of eggs,” says Eriksson.

Also, she says, just because a few dozen have been caught in each country, could just mean we’re at the very beginning of an invasion. Let’s remember at first finding an American lobster in Europe was super rare, “but since 2014, they are caught annually. Every year. So although there are not that many adults. They are reproducing, both with American offspring and with hybrid offspring.”

The Swedes’ position could be distilled thusly: What do you want to wait for, here? Do we wait until they are finding live juveniles out in the wild? A clear sign that the Americans were reproducing and succeeding in Europe. Do we wait until there are adult hybrid European-American Lobsters coming into the traps? Do you want to wait until it is too late? Is that what you want?

The Precautionary Principle

This debate is actually not really about lobsters, in my personal opinion. It’s about uncertainty, and what we should do in the face of it.

There’s this idea that environmentalists like to cite called the precautionary principle. It says that when there’s something that we can do and we don’t really know what the impact could be, the safest course of action is to do nothing.

In Europe, this is a much more prevalent idea than here in the US, and it was the the guiding philosophy that led the EU to ban genetically modified crops in the late 90s. When you read the EU’s American lobster risk assessment, it specifically says that it relies on the precautionary principle to come to its conclusion that imports should be banned.

You should actually stop ships from coming outside Europe if you want to have zero chance of anything non-native from arriving.

American regulators, on the other hand, don’t really go for this idea. We tend to prefer straight ahead cost-benefit analysis: knowing what we know, do the downsides outweigh the upsides.

The European philosophy gives a lot more deference to the incompleteness of human knowledge. It assumes that our cost benefit-analysis is going to be flawed… imperfect… that it could be missing some big downsides.

But Bob Steneck points out that the way the Europeans implement the precautionary principle leads to a kind of status quo bias. New things are seen as risky, but decisions that might be equally risky but were made a while ago are seen as okay — like letting ships release 10,000 non-native species every time they flush their ballast water. “You should actually stop ships from coming outside Europe if you want to have zero chance of anything non-native from arriving,” says Bob.

Essentially, you’d have to build a wall around every continent, “and Scandinavia is gonna pay for it,” he says.

The Decision

In the end, delegations from all the EU countries met behind closed doors and took a vote.

“I actually was in the process of doing a story with a reporter with the Financial Times, and the reporter was the one who actually called me and said, 'You guys… you’re good!'” remembers Annie Tselikis, laughing, “Which just sort of felt anti-climactic.”

According to the Swedish delegate, the Europeans agreed that American lobster was likely invasive, but given the economic impact a ban would have, they decided to reject the ban for the time being. The precautionary principle might feel like a coherent philosophy, but when there’s real money at stake, it becomes clear that it is not immune to politics and economics.

Work continues in Scandinavia to determine if the invasive threat is real or not. Susanne Eriksson says she’s next going to search for hybrid lobster larvae in the wild: a sign that reproduction in the wild was getting established. But even that isn’t enough to convince Bob Steneck, who says that he would need to see evidence that a second generation was actually established and reproducing.

What’s crazy about this debate, is trying to imagine what it would take to get either side to change their mind. Bob’s definition of the point where you start to get concerned — larva surviving to adulthood and reproducing — is the Scandinavians definition of an invasion already in progress.

So if the Swedes succeed in getting lobster imports banned next time around, they’ll think that they’ve stopped a disaster, but the Bob Stenecks of the world will always think it was overkill.

Basically the only way to settle this debate for sure would be to do nothing… and see what happens.


Outside/In was produced this week by:

Outside/In was produced this week by Sam Evans-Brown with help from: Erika Janik, Maureen McMurray, Taylor Quimby, Hannah McCarthy, Jimmy Gutierrez, and Justine Paradis.

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