Shocking Fish Photos!

There are two Conewago Creek systems in the Lower Susquehanna River Watershed.  One drains the Gettysburg Basin west of the river, mostly in Adams and York Counties, then flows into the Susquehanna at the base of Conewago Falls.  The other drains the Gettysburg Basin east of the river, flowing through Triassic redbeds of the Gettysburg Formation and York Haven Diabase before entering Conewago Falls near the south tip of Three Mile Island.  Both Conewago Creeks flow through suburbia, farm, and forest.  Both have their capacity to support aquatic life impaired and diminished by nutrient and sediment pollution.

This week, some of the many partners engaged in a long-term collaboration to restore the east shore’s Conewago Creek met to have a look at one of the prime indicators of overall stream habitat health—the fishes.  Kristen Kyler of the Lower Susquehanna Initiative organized the effort.  Portable backpack-mounted electrofishing units and nets were used by crews to capture, identify, and count the native and non-native fishes at sampling locations which have remained constant since prior to the numerous stream improvement projects which began more than ten years ago.  Some of the present-day sample sites were first used following Hurricane Agnes in 1972 by Stambaugh and Denoncourt and pre-date any implementation of sediment and nutrient mitigation practices like cover crops, no-till farming, field terracing, stormwater control, nutrient management, wetland restoration, streambank fencing, renewed forested stream buffers, or modernized wastewater treatment plants.  By comparing more recent surveys with this baseline data, it may be possible to discern trends in fish populations resulting not only from conservation practices, but from many other variables which may impact the Conewago Creek Warmwater Stream ecosystem in Dauphin, Lancaster, and Lebanon Counties.

So here they are.  Enjoy these shocking fish photos.

Electrofishing on the Conewago Creek in Lebanon County, PA
Matt Kofroth, Watershed Specialist with the Lancaster County Conservation District, operates the electrofishing wand in Conewago Creek while his team members prepare to net and collect momentarily-stunned fish.  Three other electrofishing units operated by staff from the Susquehanna River Basin Commission and aided by teams of netters were in action at other sample locations along the Conewago on this day.
Fishes of the Lower Susquehanna River Watershed: Common Carp
Really big fish, such as this Common Carp (Cyprinus carpio), were identified, counted, and immediately returned to the water downstream of the advancing electrofishing team. 
Fishes of the Lower Susquehanna River Watershed: Swallowtail Shiner, Fallfish, Red-breast Sunfish, and suckers.
Other fish, such as the Swallowtail Shiner, Redbreast Sunfish (Lepomis auritus), Fallfish, and suckers seen here,  were placed in a sorting tank.
Fishes of the Lower Susquehanna River Watershed: Fallfish
Fallfish (Semotilus corporalis) are very active and require plenty of dissolved oxygen in the water to survive.  Fallfish, Rainbow Trout (Oncorhynchus mykiss), and Smallmouth Bass (Micropterus dolomieu) were quickly identified and removed from the sorting tank for release back into the stream.  Other larger, but less active fish, including suckers, quickly followed.
Fishes of the Lower Susquehanna River Watershed: Fathead Minnow
Small fish like minnows were removed from the sorting tank for a closer look in a hand-held viewing tank.  This Fathead Minnow (Pimephales promelas) was identified, added to the tally sheet, and released back into the Conewago.  The Fathead Minnow is not native to the Susquehanna drainage.  It is the minnow most frequently sold as bait by vendors.
Fishes of the Lower Susquehanna River Watershed: a breeding male Bluntnose Minnow
A breeding condition male Bluntnose Minnow (Pimephales notatus).
Fishes of the Lower Susquehanna River Watershed: Cutlips Minnow
The Cutlips Minnow (Exoglossum maxillingua) is a resident of clear rocky streams.  Of the more than 30 species collected during the day, two native species which are classified as intolerant of persisting stream impairment were found: Cutlips Minnow and Swallowtail Shiner.
Fishes of the Lower Susquehanna River Watershed: Central Stoneroller
The Central Stoneroller (Campostoma anomalum) is a benthic feeder in creeks over gravel and sand.
Fishes of the Lower Susquehanna River Watershed: Eastern Blacknose Dace
The Eastern Blacknose Dace (Rhinichthys atratulus) is found in clear water over pebble and stone substrate.
Fishes of the Lower Susquehanna River Watershed: Longnose Dace
The Longnose Dace (Rhinichthys cataractae) is another species of pebbly rocky streams.
Fishes of the Lower Susquehanna River Watershed: juvenile Golden Shiner
A juvenile Golden Shiner (Notemigonus crysoleucas).  Adults lack the side stripe and grow to the size of a sunfish.
Fishes of the Lower Susquehanna River Watershed: Swallowtail Shiner
A Swallowtail Shiner (Notropis procne) and a very young White Sucker (Catostomus commersonii) in the upper left of the tank.
Fishes of the Lower Susquehanna River Watershed: Spotfin Shiner
A probable Spotfin Shiner (Cyprinella spiloptera).
Fishes of the Lower Susquehanna River Watershed: Spotfin Shiner
A breeding male Cyprinella shiner, probably a Spotfin Shiner.  Show-off!
Fishes of the Lower Susquehanna River Watershed: Margined Madtom
The Margined Madtom (Noturus insignis) is a small native catfish of pebbly streams.
Fishes of the Lower Susquehanna River Watershed: Banded Killifish
The Banded Killifish (Fundulus diaphanus) is adept at feeding upon insects, including mosquitos.
Fishes of the Lower Susquehanna River Watershed: a juvenile Rock Bass
A young Rock Bass (Ambloplites rupestris).  This species was introduced to the Susquehanna and its tributaries.
Fishes of the Lower Susquehanna River Watershed: Greenside Darter
The Greenside Darter (Etheostoma blennioides) is not native to the Susquehanna basin.  The species colonized the Conewago Creek (east) from introduced local populations within the last five years.
Fishes of the Lower Susquehanna River Watershed: Tessellated Darter
The Tessellated Darter (Etheostoma olmstedi) is a native inhabitant of the Susquehanna and its tributaries.
Fishes of the Lower Susquehanna River Watershed: American Eel
The stars of the day were the American Eels (Anguilla rostrata).
Fishes of the Lower Susquehanna River Watershed: American Eel
After collection, each eel was measured and weighed using a scale and dry bucket.  This specimen checked in at 20 inches and one pound before being released.
Fishes of the Lower Susquehanna River Watershed: American Eel
Prior to the construction of large dams, American Eels were plentiful in the Susquehanna and its tributaries, including the Conewago.  They’ve since been rarities for more than half a century.  Now they’re getting a lift.
Eastern Elliptio
American Eels serve as an intermediate host for the microscopic parasitic glochidia (larvae) of the Eastern Elliptio (Elliptio complanata), a declining native freshwater mussel of the Lower Susquehanna River Watershed.  While feeding on their host (usually in its gills), the glochidia cause little injury and soon drop off to continue growth, often having assured distribution of their species by accepting the free ride.  Freshwater mussels are filter feeders and improve water quality.  They grow slowly and can live for decades.
Fishes of the Lower Susquehanna River Watershed: American Eel
American Eels are a catadromous species, starting life as tiny glass eels in the saltwater of the Atlantic Ocean, then migrating to tidal brackish marshes and streams (males) or freshwater streams (females) to mature.  This 20-incher probably attempted to ascend the Susquehanna as an elver in 2016 or 2017.  After hitching a ride with some friendly folks, she bypassed the three largest dams on the lower Susquehanna (Conowingo, Holtwood, and Safe Harbor) and arrived in the Conewago where she may remain and grow for ten years or more.  To spawn, a perilous and terminally fatal journey to the Sargasso Sea awaits her.  (You may better know the area of the Sargasso Sea as The Bermuda Triangle…a perilous place to travel indeed!)

SOURCES

Normandeau Associates,  Inc. and Gomez and Sullivan.  2018.  Muddy Run Pumped Storage Project Conowingo Eel Collection Facility FERC Project 2355.  Prepared for Exelon.

Stambaugh, Jr., John W., and Robert P. Denoncourt.  1974.  A Preliminary Report on the Conewago Creek Faunal Survey, Lancaster County, Pennsylvania.  Proceedings of the Pennsylvania Academy of Sciences.  48: 55-60.