Potamopyrgus in New Jersey

Last Wednesday I received an email from Mike Cole of Cole Ecological, forwarded by our good buddy Tim Pearce.  Attached to Mike’s message was the JPEG below, from samples taken in the Musconetcong River of northwestern New Jersey, a tributary of the Delaware.  This is the third introduction of the New Zealand Mud Snail, Potamopyrgus antipodarum, confirmed for US Atlantic drainages.

From Mike Cole 4July18

We reported Potamopyrgus in Spring Creek, a tributary of the Susquehanna in central Pennsylvania, back in 2013, and the 2017 discovery in Maryland’s Gunpowder River just last month [1].  The Musconetcong, much like the Gunpowder and Spring Creek, is a lovely body of water, tumbling cold, clear and rich about 73 km through a surprisingly unspoiled valley.  Mike reports Potamopyrgus at five sites scattered along the lower 10 km of the river.

So NZMS were completely unknown in US Atlantic drainages until one day they popped up in the middle of Pennsylvania, and the next day they popped up in Maryland 50 km south, and the next day they popped up in New Jersey 200 km east.  What is going on here?

What the Musconetcong shares with Spring Creek and the Gunpowder River, in addition to NZMS introductions, is trout.  New Jersey Monthly counted the “mighty Musky” as “among the state’s most revered waterways, thanks to its ever-changing landscape and world-class fly-fishing [2].”  The river is stocked by NJ Fish & Wildlife biologists weekly in April and May, pretty much down its entire length.

My father and I used to enjoy a fair amount of trout fishing ourselves, when I was young.  Early in the spring… doggone that water was cold… we always wore hip boots.  And in fact, I’ve got at least two or three pair of boots hanging upside down in my storage room this morning.

My right boot toe

Almost all the hip boots and waders I’ve ever worn in my life had deep, heavy tread on the soles, into which mud was always caked.  But I never cleaned the soles of my boots… not in 50 years… never really thought about it.

We fishermen (and biologists) need to start thinking about it.  That mud in the soles of our boots has the potential to track a lot of hitch-hikers from one stream to the next.  And remember – Potamopyrgus are parthenogenic brooders.  There’s no such thing as “one.”  And there’s nothing to stop those critters from washing down into the Delaware River.  Darn it.

Notes

[1] Previous posts on Potamopyrgus:

• Invaders Great and Small [19Sept08]
• Potamopyrgus in US Atlantic drainages [19Nov13]
• Invasive Species Updates [13June18]

[2] NJ Monthly, 19Mar14:

Gone Fishing: Musconetcong River [html]