Men in Sweden are being warned that a cousin of the piranha fish that, according to rumors, has a taste for biting men’s testicles, has been spotted in local waters and that they should be cautious when swimming.
The fish in question is called the pacu. It shares a close resemblance to the piranha, all the way down to its rather terrifying looking teeth. The pacu is generally found in rivers and streams in the Amazon and Orinoco river basins of lowland Amazonia. That is to say, it usually enjoys decidedly warmer temperatures than Scandinavian waters can provide.
Despite this, a fisherman on August 4 pulled a 21cm pacu from Oresund, the narrow strait that separates the Danish island Zealand from Scania, a southern Swedish province.
This in itself is unusual, but perhaps not that newsworthy. That was until local museum officials started to issue a “Watch Your Testicles” warning. Interestingly, the pacu, despite its powerful jaws and unlike its bloodthirsty cousin, in fact subsists on what might be called a vegetarian diet. So why caution men to take extra care while swimming?
It turns out the fish likes, among other non-meat morsels of food, nuts from trees. Sadly they’re not that discerning and have been known to have more than just a nibble on the body parts of South American fisherman.
In fact, according to reports, they’ve even earned themselves the rather disturbing nickname “ball cutter” after apparently castrating a few unfortunate men. Whether that’s just a folktale or not is unclear but that the fish are capable of delivering a painful bite is well established, though it should be noted that in the vast majority of cases, they have shown little interest in biting people in the wild.
So how did the fish get into Scandinavian waters? Experts aren’t exactly sure. There is a leading theory, though.
It is not unlikely that someone has emptied their fish tank into a nearby stream just before a vacation and that the pacu then swam out into the brackish waters of Oresund,” Moller explained in a statement. “We don’t know of any commercial farming of pacus in Europe. But just like the piranhas the pacus are quite easy for amateurs to raise.”
Researchers still have to confirm the identity of the fish through genetic testing, since there are several species of pacu that look similar when young and hybrid species produced in the aquaculture business.
Last year, it was reported that two pacu fish were spotted in Lake Lou Yaeger in Illinois. Here’s a video report on that discovery:
Whether the pacu have invaded Scandinavian waters through mishap or intent is unclear, but what several commentators have noted is that the pacu should not find the cold Scandinavian waters particularly hospitable. If, then, a wider population is discovered this would certainly be cause for concern and may in part lead us to suspect at least a little helping hand from global sea temperature rise.
That issue aside, there is plenty of cause for concern if we confine ourselves only to the issue of the pacu as an invasive species.
Indeed, Illinois is not alone in terms of U.S. states that have been so blessed by the testicle torturing fish: states from California to Washington, Wyoming to Minnesota and more have all seen reports of this fearsome nibbler.
The most likely culprit is, again, fish farming or exotic fish collectors who, if you’ll pardon the pun, are biting off more than they can chew with a fish that can potentially grow to weigh as much as 55 pounds.
Admittedly, it is unlikely the pacu will be causing mass sterilization among swimmers as in general they are not an overly confident fish, but this story, with its media friendly angle, touches on the wider problem of invasive species.
Examples of other such species are plentiful, to name just a few: the African Clawed Frog that spread a deadly disease to other frogs even though it itself is immune, and the Asian Ladybug whose voracious appetite and robust disposition has seen it flourish throughout Europe at the expense of Europe’s native species.
Here’s the central concern: when an invasive species enters the local habitat, it almost certainly will push other species out, and the pacu is known to eat other fish when its main food sources are scarce. That’s why scientists are keen to keep an eye on the pacu’s behavior and numbers.
So while museum experts run genetic tests on the fish, what is their advice for men and women in the region who enjoy a swim?
One expert is quoted as saying “Anyone choosing to bathe in the Oresund these days had best keep their swimsuits well tied.”
Sage advice indeed.