Are sailfish really native to the Atlantic Ocean?

Wikipedia’s article for Sailfish (Istiophorus platypterus), says that surprisingly (at least to me), sailfish are in fact native to the Indo-Pacific, and that Atlantic populations got there crossing the Suez Canal.Is this really true? I have not found any other source that confirms what Wikipedia says, though, and although sailfish is accepted now as a single species, in the past, the Atlantic population had its own species.

So, are Sailfish native to the Atlantic? Or they shouldn’t be there at all?

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While I don’t have any expertise on any marine fish, I think it is unlikely they were brought there by humans. Especially given the difference in appearance compared to the Indo-Pacific population, which to me would suggest that the populations have been separated for quite a while. (What would be the motive of people bringing them to the Atlantic a few centuries back, did they even have the necessary technologies back then?)

My hypothesis would be that once upon a time there was a large interconnected population and due to changing environmental factors, they got separated. If that is the case, maybe they will become separate species after all in “a few” years time (a few in the sense of relative to normal evolutionary timescales). I sadly couldn’t find anything online about how long it is assumed sail fish have existed on earth to confirm or disprove this though.

It’s interesting though. Definitely sounds like a cool topic to do research on! :D

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Did you look at the Wikipedia source?

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I think the confusion is because some recognize the Atlantic and Indo-Pacific forms as separate species, others as the same species. You have to know which taxonomy is being used in any article about this fish.

Apparently the Indo-Pacific form entered the Mediterranean via the Suez Canal. But the Atlantic form was already in the Mediterranean or at least in other Atlantic waters where it’s native. This is my speculation, haven’t done a deep dive into the topic.

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Wikipedia’s article

On the English one I presume. On the French Wikipedia they say:

Istiophorus platypterus est sporadiquement observé en Méditerranée. Il ne s’agit cependant pas d’une espèce lessepsienne, des individus y ayant déjà été pêchés avant l’ouverture du canal de Suez

That is: Istiophorus platypterus were in the Mediterranean before the Suez Canal was built. Weird!

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Yes, it’s saying that sailfish are not a Lessepsian species – that is, a species that got to the Mediterranean from the Red Sea via the Suez Canal – because sailfish were already native to the Atlantic including the Mediterranean. But if you believe the Indo-Pacific fish are a different species from the Atlantic, then it’s a more significant movement of a Red Sea species into the Mediterranean and would be classified as a Lessepsian invasive.

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The article said that they crossed on their own through the canal.

Yes, I did. I think it was the UICN website and said nothing about that.

Edit: Checked again, and found this:

‘‘Sailfish are reported (always as Istiophorus albicans) to have entered the Mediterranean Sea from the Red Sea via the Suez Canal, although the records are few and mostly based on juvenile specimens; there are also some records there from before the opening of the Suez Canal, possibly indicating Atlantic vagrants.’’

English Wikipedia took half of that quote and French Wikipedia took the other half!
So, that text seemed not to refer about its presence in the Atlantic, but in the Mediterranean.

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