Co-authored by Point Blue’s Nat Seavy-
In 2010, a lone grey whale was spotted in the North Atlantic – the first sighting in about 200 years. Photo: AP
December 1, 2015 by Chelsea Harvey
In the spring of 2010, a lone grey whale was spotted off the Mediterranean coast of Israel, an event that sparked international interest for an important reason: It was the first North Atlantic sighting of a grey whale, a species nowadays restricted to the Pacific Ocean, in about 200 years. The case is just one example in a recent spate of animals turning up in places they don’t belong – generally, either Pacific species showing up in the Atlantic, or vice versa. Northern gannets, a North Atlantic species, have been spotted off the coast of California several times in recent years, for instance, while several Pacific species of auks, a type of diving bird, have recently been observed in the Atlantic. It’s a perplexing – yet apparently increasing – trend. And while animals do occasionally wander outside of their ranges, scientists are starting to believe that the recent flurry of movements between the Atlantic and Pacific ocean basins are early evidence of yet another consequence of climate change. They’re arguing that as sea ice continues to melt in the Arctic, passageways are opening for certain animals – heretofore restricted by the ice – to start moving through, enabling them to cross into new territories. This is the focus of a new paper , released in the journal Global Change Biology, that explores the recent uptick in what the authors refer to as “faunal exchange,” or the movement of wildlife between the Atlantic and Pacific ocean basins, via the Arctic. Such movements are likely to be made possible by the opening up of passageways, including the famed Northwest Passage, a shipping route through the Arctic currently largely blocked by sea ice…..
Accelerated loss of sea ice in the Arctic is opening routes connecting the Atlantic and Pacific Oceans for longer periods each year. These changes may increase the ease and frequency with which marine birds and mammals move between the Pacific and Atlantic Ocean basins. Indeed, recent observations of birds and mammals suggest these movements have intensified in recent decades. Reconnection of the Pacific and Atlantic Ocean basins will present both challenges to marine ecosystem conservation and an unprecedented opportunity to examine the ecological and evolutionary consequences of interoceanic faunal exchange in real time. To understand these changes and implement effective conservation of marine ecosystems, we need to further develop modeling efforts to predict the rate of dispersal and consequences of faunal exchange. These predictions can be tested by closely monitoring wildlife dispersal through the Arctic Ocean and using modern methods to explore the ecological and evolutionary consequences of these movements.
McKeon, C.S., M.X. Weber, S.E. Alter, N.E. Seavy (Point Blue), E.D. Crandall, D.J. Barshis, E.D. Fechter-Leggett, K.L.L. Oleson. 2015. Melting barriers to faunal exchange across ocean basins. Global Change Biology