If you were hoping the next invasion of New York would be somewhat less eight-legged, we’ve got bad news: invasive crabs that harass fishers, alter food webs, and even shut down power plants have made it to the state’s waters. On the upside, they do have very cute little mittens.
Describing it as “anything but crabulous”, the New York State Department of Environmental Conservation (NYS-DEC) announced on social media last week that Chinese mitten crabs (Eriocheir sinensis) had been found in the Nissequogue River this past winter. Since then, the crabs have made their way into the Hudson and Long Island Sound.
Mitten crabs are appropriately named, given their distinguishing feature is a pair of “furry” claws that look like, well, mittens. However, it’s not actually fur; it’s a dense patch of setae, which are stiff, hair-like structures that can also be found in some insects and geckos.
Their resemblance to cold weather gear might make it seem as though the crabs are simply well-prepared for all weathers, but the actual purpose of the mittens – if there even is one, sometimes nature just likes to fuck around and find out – remains unclear.
But while their furry forelimbs might earn them some fans, their appearance in New York is not welcome.
Mitten crabs are actually native to East Asia, making them an invasive species in the US. It’s thought they managed to reach the States either accidentally, such as in the ballast water of a ship, or were introduced on purpose as a delicacy.
Though we’re yet to see the impact of their arrival in New York, we know from their invasion of both European and Californian waters that they can wreak havoc in all sorts of ways. It seems they’ve got it in for the fishing and energy industries in particular, as according to the NYS-DEC, they’ve been found to steal bait, damage gear and catch, and block the cooling systems of power plants.
If that gives the illusion of mitten crabs being passionate about the environment, then you should also know that these furry fiends can cause instability in riverbanks, alter food webs because they can snack on multiple different things, and compete with native species for food and a place to live.
Given their potential impact, officials are keen to keep an eye on them, with the help of the public. So how do you recognize a mitten crab?
The most obvious feature is their furry claws, but juvenile crabs don’t always have these. In that case, the NYS-DEC recommends looking for “a notch on the carapace between the eyes and four small lateral spines on each side of the carapace.”
If you manage to spot one, “Do not throw it back alive!” says the Smithsonian Environmental Research Center. That sounds ominous, but the advice goes on to say that mitten crabs should be frozen and then reported to the authorities.
Low on freezer space? Thinking that a spot of crab might make a nice lunch? Mitten crabs are edible, but take caution: they are carriers of parasitic worms that can also infect humans.
