Shakedown Cruise of the S. S. Haldeman

First there was the Nautilus.  Then there was the Seaview.  And who can forget the Yellow Submarine?  Well, now there’s the S. S. Haldeman, and today we celebrated her shakedown cruise and maiden voyage.  The Haldeman is powered by spent fuel that first saw light of day near Conewago Falls at a dismantled site that presently amounts to nothing more than an electrical substation.  Though antique in appearance, the vessel discharges few emissions, provided there aren’t any burps or hiccups while underway.  So, climb aboard as we take a cruise up the Susquehanna at periscope depth to have a quick look around!

Brunner Island as seen from the east channel.
Close-in approach to emergent Water Willow growing on an alluvial Island.
The approach to York Haven Dam and Conewago Falls from the west channel.
A pair of Powdered Dancers on a midriver log.

Watertight and working fine.  Let’s flood the tanks and have a peek at the benthos.  Dive, all dive!

American Eelgrass, also known as Tapegrass, looks to be growing well in the channels.  Historically, vast mats of this plant were the primary food source for the thousands of Canvasback ducks that once visited the lower Susquehanna each autumn.
As is Water Stargrass (Heteranthera dubia).  When mature, both of these native plants provide excellent cover for young fish.  Note the abundance of shells from deceased Asiatic Clams (Corbicula fluminea) covering the substrate.
Mayfly nymph
A three-tailed mayfly (Ephemeroptera) nymph and a several exoskeletons cling to the downstream side of a rock.
Comb-lipped Casemaker Caddisfly larva and case.
This hollowed-out stick may be a portable protective shelter belonging to a Comb-lipped Casemaker Caddisfly larva (Calamoceratidae).  The larva itself appears to be extending from the end of the “case” in the upper right of the image.  Heteroplectron americanum, a species known for such behavior, is a possibility. 
Rusty Crayfish
In the Susquehanna and its tributaries, the Rusty Crayfish (Faxonius rusticus) is an introduced invasive species.  It has little difficulty displacing native species due to its size and aggressiveness.
Rusty Crayfish
A Rusty Crayfish.
Freshwater Snails Susquehanna: Virginian River Horn Snail
Summers with conditions that promote eelgrass and stargrass growth tend to be big years for Virginian River Horn Snails (Elimia virginica).  2022 appears to be one of those years.  They’re abundant and they’re everywhere on the rocks and gravel substrate in midriver.  Feeding almost incessantly on algae and detritus, these snails are an essential component of the riverine ecosystem, breaking down organic matter for final decomposition by bacteria and fungi.
Freshwater Snails Susquehanna: Virginian River Horn Snail
Bits of debris suspended in the flowing water streak by this Virginian River Horn Snail.  The spire-shaped shell is a streamlining adaptation for maneuvering and holding fast in the strong current.
Freshwater Snails Susquehanna: Virginian River Horn Snail
A young Virginian River Horn Snail following a mature adult.  Note the green algae growing among the decaying plant and animal remains that blanket the river bottom.
Freshwater Snails Susquehanna: Virginian River Horn Snail
Two of a population that may presently include millions of Virginian River Horn Snails living downstream of Conewago Falls.
Susquehanna Snails: Virginian River Horn Snails and Lesser Mystery Snails
Virginian River Horn Snails with Lesser Mystery Snails (Campeloma decisum), another native species commonly encountered at Conewago Falls and in surrounding waters.
Freshwater Snails Susquehanna: River Snail and Virginian River Horn Snail
A River Snail (Leptoxis carinata), also known as a Crested Mudalia, hitching a ride on a Virginian River Horn Snail.  The two species are frequently found together.
Mollusks of the Susquehanna: Yellow Lampmussel and River Snail
A River Snail cleaning the shell of a native freshwater Unionidae mussel, Lampsilis cariosa, commonly called the Yellow Lampmussel or Carried Lampmussel.  Because of their general decline in abundance and range, all Unionidae mussels are protected in Pennsylvania.
Fishes of the Susquehanna: Banded Darter
The Banded Darter (Etheostoma zonale) is a member of the perch family (Percidae).
Fishes of the Susquehanna: Smallmouth Bass
A Smallmouth Bass in strong current.
Fishes of the Susquehanna: Spotfin or Satinfin Shiners
Along the edge of an alluvial island at midriver, Cyprinella (Spotfin or Satinfin) Shiners gather in the cover of an emergent stand of Water Willow.  The closely related Spotfin Shiner (Cyprinella spiloptera) and Satinfin Shiner (Cyprinella analostanus) are nearly impossible to differentiate in the field.
Fishes of the Susquehanna: Spotfin or Satinfin Shiner
A breeding condition male Cyprinella (Spotfin or Satinfin) Shiner.
Fishes of the Susquehanna; Juvenile Channel Catfish
A juvenile Channel Catfish.

We’re finding that a sonar “pinger” isn’t very useful while running in shallow water.  Instead, we should consider bringing along a set of Pings—for the more than a dozen golf balls seen on the river bottom.  It appears they’ve been here for a while, having rolled in from the links upstream during the floods.  Interestingly, several aquatic species were making use of them.

River Snail cleaning a golf ball.
River Snail cleaning a golf ball.
Net-spinning Caddisfly (Hydropsychidae)
A golf ball used as an anchor point for silk cases woven by Net-spinning Caddisfly (Hydropsychidae) larvae to snare food from the water column.
Freshwater Snails (Gastropods) of the Lower Susquehanna River Watershed: Creeping Ancylid (Ferrissia species)
A Creeping Ancylid (Ferrissia species), a tiny gastropod also known as a Coolie Hat Snail, River Limpet, or Brook Freshwater Limpet, inhabits the dimple on a “Top Flight”.
Freshwater Snails (Gastropods) of the Lower Susquehanna River Watershed: Creeping Ancylid (Ferrissia species)
A closeup view of the Creeping Ancylid.  The shell sits atop the snail’s body like a helmet.
We now know why your golf balls always end up in the drink, it’s where they go to have their young.

Well, it looks like the skipper’s tired and grumpy, so that’s all for now.  Until next time, bon voyage!

Photo of the Day

Damselflies and dragonflies of the Lower Susquehanna River Watershed: Fragile Forktail
Fragile Forktail damselflies have matured from their aquatic nymphal stage (see “Photo of the Day” from April 24, 2022) into flying adults.  This breeding pair in the “wheel position”, male above and female below, were photographed this week along the edge of the pond at the susquehannawildlife.net headquarters.  You can identify the odonates you see during coming weeks by clicking the “Damselflies and Dragonflies” tab at the top of this page.  There, a gallery of images that includes the Lower Susquehanna River Watershed’s most frequently encountered species will be at your fingertips for easy perusal.

Photo of the Day

Dragonflies and Damselflies of the Lower Susquehanna River Watershed: Fragile Forktail nymph
The aquatic larval stage of a damselfly is commonly known as a nymph.  It feeds on small underwater invertebrates, then, as an adult, transitions to grabbing flying insects in midair.  While many species inhabit streams, Fragile Forktail (Ischnura posita) nymphs are found primarily in wetlands and small pools of water. This one was produced from eggs laid last summer among submerged vegetation in the susquehannawildlife.net headquarters pond.  In just a few weeks, it will climb a stem or cluster of leaves and transform into a colorful adult-stage damselfly known as an imago.  To see a photo gallery featuring this and other species of odonates found in the Lower Susquehanna River Watershed, click on the “Damselflies and Dragonflies” tab at the top of this page.

Damselflies and Dragonflies Galore at Gifford Pinchot State Park

Some of of you may have been wondering why there has been no new content for a while.  Well, rest assured that your editor has been replumbed and rewired by some of the best in the business during his recent stay at the Milton S. Hershey Medical Center and he is getting a little stronger every day.  More field trips will be on the way soon!

In the meantime, have a look at some of the wide variety of dragonflies gathered along the shoreline at Gifford Pinchot State Park in York County, Pennsylvania.  The lake was drained during the winter to perform some maintenance projects and has yet to refill because of the dry spring and early summer we’ve been experiencing.  These photos show species seen mostly in the vegetated shallows near the dam.

An ever-on-the-wing Common Green Darner.
A Unicorn Clubtail (Arigomphus villosipes).
A Black-shouldered Spinyleg (Dromogomphus spinosus).
A male Slaty Skimmer (Libellula incesta).
A male Slaty Skimmer.
A female Slaty Skimmer.
A female Swamp Darner (Epiaeschna heros) ovipositing.
Very common damselflies, Familiar Bluets (Enallagma civile), a breeding male (right) and female (left) in wheel position.
Another common damselfly, a male Powdered Dancer (Argia moesta).
Breeding Great Blue Skimmers (Libellula vibrans) in wheel position.
Lancet Clubtails (Phanogomphus exilis), a male (above) and a female (below) in wheel position.
Black Saddlebags, a male (right) clasping a female (left).

There are lots of others there too.  Do have a look.