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Counting crabs and measuring climate change

posted Nov 17, 2015, 4:54 PM by SOS SaveOceanScience   [ updated Nov 17, 2015, 4:54 PM ]
Martin Wightman
   Dr. Gerhard Pohle is quick to clarify that a spike-covered blowfish on his shelf isn’t native to these waters. He brings out a stone crab for a more New Brunswick-appropriate photo-op. And he should know.   Pohle has been counting crustaceans and curating the invertebrates collection at the Atlantic Reference Centre in Saint Andrews since 1984. The centre is a research museum that houses specimens of marine life found everywhere from the Arctic to the Gulf of Maine.   “It all boils down to what species live in the water. That’s our bread and butter,” says Pohle, now the centre’s director.“But we’re using this basic tool to try and understand the bigger picture, what’s going on in the world.”   The reference centre is a partnership between the not-for-profit Huntsman Marine Science Centre and the federal Fisheries and Oceans department, and Pohle has been there since its inception.   There is indeed a large library of jars full of preserved fish and crabs of all sorts, but Pohle also works on applied projects that use the tools of biodiversity research to answer bigger questions. The centre’s core task of taxonomy has expanded, and the centre now has partnerships with industry and public bodies alike.   “The spectrum can be anything from somebody coming from the public and saying ‘I found this on the beach, what is it?’ – we do that – to more elaborate things like this where we have a rigorous sampling program and we identify everything that is brought to us.”   One of the “more elaborate things” Pohle refers to is a set of long-term studies into the effects of aquaculture.   “In the 1990s, I was involved in a study, probably the first of its kind in the area, looking at regional impacts, far-field impacts, of aquaculture. As you know, that is a very large industry in this area. This was a pioneering study, because not only did it look at far-field effects – so, not what happens at a cage, but away from the cage – but also documented that there were some effects from aquaculture in the far field.”   “That’s a while ago, and basically what we are doing now, in co-operation with the government, and industry, we’re doing a followup, repeating the work. It’s looking at the species, the community structure of things that live in that area, and trying to understand what changes are taking place over time in these areas of aquaculture versus a reference site, where there is no aquaculture.”   Aquaculture itself has changed over the past 20 years, and a new iteration of the same study can help quantify how those changes affect sea life. The final year of data collection has just been completed.   Pohle has also worked on projects to get an inventory of marine life in the arctic and see how it’s shifted in recent years – data that’s vital to understanding the effects of climate change. And he’s been part of assessments of planned marine protected areas in the Atlantic region.   The variety of the job is a selling point for Pohle, whose academic background was very specific.   “I did my PhD work at the University of Toronto on parasitic crabs, which is a rather esoteric subject.   “But to this day, that’s probably what I’m quite well-known for.”   It was during his time in Toronto, where he completed both a B.Sc. and a PhD, that Pohle encountered the Huntsman.   “Coming from a place like Toronto – and there are many other landlocked universities – it was such an eye-opener when you came here to Huntsman, because it wasn’t the standard lecture course that you would take at a university. First, you get the field experience, but you also get to work in very close quarters over very short periods of time, and very intensely. If that doesn’t interest you, then obviously this is not your career choice.”   Having reliable data on the biodiversity in our oceans can provide an early warning to the effects of climate change or risks to species before they’re on the brink, Pohle says. Has there been a shift in the numbers of suspension feeders versus bottom feeders, for example?   The small shifts in community structure are harder to read, but essential to understanding environmental changes as they’re occurring, rather than after the fact.   But sometimes the revelation is more obvious: the presence of a new species in Canada, such as crab found by Brent Wilson, a University of New Brunswick graduate student doing work at the reference centre. It was, Pohle says,“a very very unusual crab.”   “And I should be knowing my crabs. Turns out this was a crab that was originally described in Barbados, the Caribbean. In deep waters, mind you, but still, has never been found here, so this is the first record of such a crab in Canadian waters, so this is something that will get published soon. Another one would be that we have found European shrimp species in the Gulf.”   Even in taxonomy, nothing stays the same. Pohle likes it that way.   “I guess the part that I like is that I feel I am contributing to the bigger picture of understanding what’s happening in the world – rather than simply fulfilling a service.”   Martin Wightman   Science and research columnist, and copy editor at Brunswick News. In the Lab appears every other week in Innovate
A blowfish guard the files on a shelf in Dr. Gerhard Pohle’s office at the Atlantic Reference Centre in Saint Andrews.   Photo: Martin WightMan
Dr. Gerhard Pohle holds a Norway king crab, commonly called a stone crab, at the Atlantic Reference Centre in Saint Andrews. Photo: Martin WightMan
Dr. Gerhard Pohle among the racks of jars filled with sea-life specimens, all housed at the Atlantic Reference Centre in Saint Andrews. Photo: MartIN WIghtMaN