Gulf Stream orphans is a term for tropical fish who took a journey far from home via the Gulf Stream and ended up in northern waters, like here off Cape Cod.
Associate Curator of Aquatic Collections at the New England Aquarium Mike O'Neill launched the Gulf Stream Orphan Project a decade ago. Now, he and his colleagues have published a paper that looks at all the data they've collected over the years.
Gilda Geist Mike, I want to talk about this term, Gulf Stream orphans. Where does that term come from?
Mike O’Neill So that is a term that has been used here at the aquarium for a while. These fish have been called a variety of things depending on where you are. They also are referred to as tropical strays and Gulf Stream riders.
These are unusual tropical and subtropical species that show up here naturally every summer and fall, but it's due to getting carried by the Gulf Stream. And the Gulf Stream is this massive mover of water that carries tropical water northward from the Caribbean, and water from the Gulf Stream can make landfall in Massachusetts and along the coast of North America. In all that water from the tropics are the planktonic forms and juvenile life stages of a lot of different species. When our environmental conditions in the summer and fall are warm enough, the species from the tropics can continue to survive that transport, and then they arrive along our coasts and continue to grow up and develop and take their role in our ecosystems.
GG So for this project, it seems like you relied a lot on data collected by regular, non-science people like me. Is that right?
MO That's correct, yeah. So iNaturalist is an awesome platform that lets anybody who's out there in nature document it and report it. It has a huge user base—millions of people, millions of reports. And then researchers specializing in different things can use that information.
For Gulf Stream Orphans, we wanted to leverage that group because we know how difficult they are to find. These fish are young of the year, so they might be smaller than an inch. And they're typically reef species, so they like to live in cracks and crevices. And we know that they're relatively rare. So citizen science was a great avenue to pursue because it allows us to crowdsource all of that effort.
GG So after all these years of crowdsourcing all this data, the Gulf Stream Orphans project recently published a research paper in the journal "Fisheries." What were some of the biggest takeaways from that paper?
MO One thing we wanted to learn about was regional and interannual variation over time. And we wanted to look at the timing of when we'd see these tropical and subtropical fish reported. And then we also wanted to sort of build as comprehensive a species list as we could.
Now we want to sort through those regional differences and see if we can tease out whether or not these fish are most likely to be dispersed by the Gulf Stream, whether or not they're seasonal visitors that maybe hang out in the Mid Atlantic region, and they creep up to southern New England, but they don't really get further than that. And then also look at relative numbers year to year. What are the component parts that shape the fish that we ultimately find, or the fish that ultimately get reported to this project?
GG You know, we hear a lot that the North Atlantic is the fastest warming patch of ocean in the world. So when I got this press release, I kind of expected there to be some sort of climate change aspect. I thought maybe you guys would have found that our fast warming waters here in Massachusetts are bringing more Gulf Stream orphans than ever to our area. Is that something you guys are looking into?
MO Yeah, definitely those are the kinds of questions that we want to continue to ask. We assume that the underlying trend will be that conditions are favoring warmer water species over time. And then we would assume that if these fish are tolerant of warmer temperatures, that they are going to be more comfortable here for longer. So some of the questions we want to compare year-to-year are: When is the earliest sighting each year? Are these fish residing for longer periods of time in the summer and fall as our waters are getting warmer? And then, if they're able to reside longer, that means they're going to be growing more. They're going to be having more of an ecological impact. What is that going to do in terms of the interconnections with the species we would typically see? Are there circumstances in which we may have some displacement of different species?
These are kind of all the different ecosystem questions that we should be asking. And we wanted to highlight the fact that citizen science can contribute information to those questions that should be complementary to all of the other ways in which we study our oceans and ways in which we gather information about them.
