Marine environments are typically considered more open than those on land when it comes to animal movement. On land, the range of a species can be limited by geographic features like mountain ranges, canyons, rivers, and anything else that might get in the way. In the ocean, however, actively swimming animals like, say, large sharks have few physical barriers and may instead be restricted by their own environmental preferences. This is why in unusually warm summers you might see tropical fishes in southern New England. Because of this, one of the anticipated consequences of warming ocean temperatures is shifting distributions of mobile and highly migratory species. Basically, changes in temperature are likely to allow marine animals to move into places they haven’t before, and if those temperature changes become consistent, these species might make regular visits or even just start staying there.

This kind of change is already happening and has been documented across a variety of marine species. Now, findings from a new paper in Scientific Reports by me and co-authors from the North Carolina Division of Marine Fisheries, Simon Fraser University, and East Carolina University show an apex predator may be joining the northward shift.

Juvenile Bull Shark captured in Pamlico Sound, North Carolina. Photo from the Smithsonian Environmental Research Center.

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