Fishes

of the Lower Susquehanna River Watershed

With (forthcoming) commentary on the species including notes from the historic writings of nineteenth-century geologist, naturalist, and philologist Professor Samuel Steman Haldeman, Linnaean Society of Lancaster City and County naturalist Jacob Stauffer, and ichthyologist Tarleton Hoffman Bean.

Samuel Staman Haldeman — Samuel Steman Haldeman was born in 1812 at Locust Grove along the Susquehanna River just downstream of Conewago Falls near Bainbridge, Lancaster County, Pennsylvania. In 1842 and 1844, he was the first to describe the Chesapeake Logperch (Percina bimaculata), a fish which was long considered to be synonymous with the widespread Common Logperch (Percina caprodes) until recent mitochondrial DNA analysis proved it to be a valid species unique to the lower Susquehanna and other tributaries of the upper Chesapeake Bay. (Mathew Brady image-Library of Congress)

Tarleton Hoffman Bean (back row left) with co-members of the Smithsonian Institution staff, circa 1878. Bean was born in Bainbridge, Lancaster County, Pennsylvania, in 1846 and spent his youth along the Susquehanna River there. He studied botany at the nearby Millersport State Normal School, present-day Millersville University. (Smithsonian National Museum of Natural History image www.si.edu)

SPECIES STATUS KEY

extinct-a native species no longer existing or living.

extirpated-a native species no longer occurring in the wild in the Lower Susquehanna River Watershed.

exotic-a free-ranging escaped or released non-native species or variety; most are unwanted pets, domesticated farm animals, or zoo specimens.

introduced-a non-native species released into the waters of the Susquehanna watershed, including fishes stocked to create temporary populations as well as those that establish self-sustaining breeding populations—often at the expense of one or more native species. Introduced fishes include “native transplants”, species native to North American waters, but not indigenous to the Susquehanna and its tributaries.

Federally Endangered-a native species listed by the United States government as imminently in danger of extinction.

PA Endangered-a native species listed by the Commonwealth of Pennsylvania as imminently in danger of extinction or of extirpation as a breeding species in the state.

MD Endangered-a native species listed by the State of Maryland as imminently in danger of extinction or of extirpation as a breeding species in the state.

Federally Threatened-a native species listed by the United States government as under threat to become an endangered species in the foreseeable future.

PA Threatened-a native species listed by the Commonwealth of Pennsylvania as under threat to become an endangered species in the state in the foreseeable future.

MD Threatened-a native species listed by the State of Maryland as under threat to become an endangered species in the state in the foreseeable future.

PA Candidate-an uncommon native species that could, in the future, become listed by the Commonwealth of Pennsylvania as endangered or threatened in the state.

A LIST OF THE FISHES

of the Lower Susquehanna River Watershed

Classified using traditional taxonomic ranks and selected cladistic groups.

Domain-Eukaryota

Kingdom-Animalia

Phylum-Chordata

Class-Hyperoartia?:

The lampreys, a group with disputed relationships to other chordates, are, in accordance with traditional listings of fishes, placed here.

Order-Petromyzontiformes

Family-Petromyzontidae

Lampetra aepyptera (Least Brook Lamprey)-PA Candidate

Petromyzon marinus (Sea Lamprey)

Fishes of the Lower Susquehanna River Watershed: Least Brook Lamprey — **Least Brook Lamprey** (*Lampetra aepyptera)*. (United States Fish and Wildlife Service image of specimen in NCTC Freshwater Fisheries Teaching Collection)

Fishes of the Lower Susquehanna River Watershed: Sea Lamprey — **Sea Lamprey** (*Petromyzon marinus)*. (NOAA Fisheries image by Paul Music)

Subphylum-Vertebrata

Superclass-Osteichthyes/Clade-Euteleostomi:

The “bony vertebrates” including the Actinopterygians, the ray-finned fishes, and the Sarcopterygians, the lobe-finned fishes and tetrapods. All members of the clade Sarcopterygii presently occurring in the Susquehanna watershed (amphibians, reptiles, birds, and mammals including humans) are tetrapod descendants of extinct lobe-finned fishes.

Class/Clade-Actinopterygii:

The ray-finned fishes.

Order-Acipenseriformes

Family-Acipenseridae

Acipenser brevirostrum (Shortnose Sturgeon)-Federally Endangered/PA Endangered/MD Endangered

Acipenser oxyrhynchus (Atlantic Sturgeon)-extirpated-Federally Endangered/PA Endangered/MD Endangered

Fishes of the Lower Susquehanna River Watershed: Shortnose Sturgeon — **Shortnose Sturgeon** (*Acipenser brevirostrum).* (NOAA image)

Fishes of the Lower Susquehanna River Watershed: Atlantic Sturgeon — **Atlantic Sturgeon** (*Acipenser oxyrhynchus)*. (NOAA image)

Order-Lepisosteriformes

Family-Lepisosteridae

Lepisosteus osseus (Longnose Gar)-extirpated

Fishes of the Lower Susquehanna River Watershed: Longnose Gar — **Longnose Gar** (*Lepisosteus osseus)*. (United States Fish and Wildlife Service image by Ryan Hagerty)

Order-Amiiformes

Family-Amiidae

Amia calva (Bowfin)-introduced

Fishes of the Lower Susquehanna River Watershed: Bowfin — **Bowfin** (Amia calva) are indigenous to the Great Lakes, the Mississippi and Ohio Rivers, and the Atlantic and Gulf Coastal Plains south of Virginia. They were introduced into the lower Susquehanna River as native transplants in the years prior to 1972’s Hurricane Agnes. Few were seen after the polluted floodwaters receded. (United States Fish and Wildlife Service image by Ryan Hagerty)

Order-Anguilliformes

Family-Anguillidae

Anguilla rostrata (American Eel)

Fishes of the Lower Susquehanna River Watershed: American Eel — **American Eel** (*Anguilla rostrata).* (Vintage 35 mm image)

Order-Clupeiformes

Family-Clupeidae

Alosa aestivalis (Blueback Herring)

Alosa mediocris (Hickory Shad)-PA Endangered

Alosa pseudoharengus (Alewife)-introduced

Alosa sapidissima (American Shad)

Dorosoma cepedianum (Gizzard Shad)

Fishes of the Lower Susquehanna River Watershed: Blueback Herring and Alewife — A **Blueback Herring** (*Alosa aestivalis*on) on the top and, for comparison, an Alewife (*Alosa pseudoharengus) on the* bottom. (NOAA Fisheries image)

Fishes of the Lower Susquehanna River Watershed: Hickory Shad — **Hickory Shad** (*Alosa mediocris).*

Fishes of the Lower Susquehanna River Watershed: Alewife — **Alewife** (*Alosa pseudoharengus) during migration.* (NOAA Fisheries image by Jerry Prezioso)

Fishes of the Lower Susquehanna River Watershed: American Shad — A catch-and-release angler returning an **American Shad** (*Alosa sapidissima)* to the Susquehanna River. (Vintage 35 mm image)

Fishes of the Lower Susquehanna River Watershed: American Shad and Alewife — An **American Shad** (*Alosa sapidissima)* on the top and, for comparison, an **Alewife** (*Alosa pseudoharengus)* on the bottom. (NOAA Fisheries image by Jim Hawkes)

Fishes of the Lower Susquehanna River Watershed: Gizzard Shad using fish passage — **Gizzard Shad** (*Dorosoma cepedianum)* swimming by the counter’s window at the York Haven Dam Fish Passage just upstream from Conewago Falls.

Fishes of the Lower Susquehanna River Watershed: Juvenile Gizzard Shad — Schooling juvenile **Gizzard Shad** (*Dorosoma cepedianum)*. (Vintage 35 mm image)

Order-Cypriniformes

Family-Cyprinidae

Campostoma anomalum (Central Stoneroller)

Carassius auratus (Goldfish)-introduced

Clinostomus elongatus (Redside Dace)-upper Susquehanna species

Clinostomus funduloides (Rosyside Dace)

Ctenopharyngodon idella (Grass Carp)-introduced

Cyprinella analostanus (Satinfin Shiner)

Cyprinella spiloptera (Spotfin Shiner)

Cyprinus carpio (Common Carp)-introduced

Cyprinus rubrofuscus (Amur Carp—including ornamental Koi)-exotic

Exoglossum maxillingua (Cutlip Minnow)

Hybognathus regius (Eastern Silvery Minnow)

Luxilus cornutus (Common Shiner)

Margariscus margarita (Pearl Dace)-MD Threatened

Nocomis micropogon (River Chub)

Notemigonus crysoleucas (Golden Shiner)

Notropis amoenus (Comely Shiner)

Notropis atherinoides (Emerald Shiner)-exotic

Notropis bifrenatus (Bridle Shiner)-upper Susquehanna species-PA Endangered

Notropis buccatus (Silverjaw Minnow)

Notropis hudsonius (Spottail Shiner)

Notropis procne (Swallowtail Shiner)

Notropis rubellus (Rosyface Shiner)

Notropis volucellus (Mimic Shiner)-introduced ?

Phoxinus eos (Northern Redbelly Dace)-extirpated-upper Susquehanna species-PA Endangered

Pimephales notatus (Bluntnose Minnow)

Pimephales promelas (Fathead Minnow—including “Rosy-red Minnow)-introduced

Rhinichthys atratulus (Eastern Blacknose Dace)

Rhinichthys cataractae (Longnose Dace)

Semotilus atromaculatus (Creek Chub)

Semotilus corporalis (Fallfish)

Tinca tinca (Tench)-introduced

Large Minnows

Large Shiners

Minnows

(with a splint-like first ray in the dorsal fin)

Shiners

Bottom-dwelling Minnows

Fishes of the Lower Susquehanna River Watershed: Central Stoneroller — **Central Stoneroller** (Campostoma anomalum).

Fishes of the Lower Susquehanna River Watershed: Goldfish — **Goldfish** (Carassius auratus).

Fishes of the Lower Susquehanna River Watershed: Rosyside Dace — **Rosyside Dace** (*Clinostomus funduloides).* (United States Fish and Wildlife Service image by Ryan Hagerty)

Fishes of the Lower Susquehanna River Watershed: Grass Carp — **Grass Carp** (*Ctenopharyngodon idella).* (United States Fish and Wildlife Service image by Ryan Hagerty)

Fishes of the Lower Susquehanna River Watershed: Satinfin/Spotfin Shiners — Within the Lower Susquehanna River Watershed, there are two shiners in the genus Cyprinella: the **Satinfin Shiner** (C. analostanus) and the **Spotfin Shiner** (C. spiloptera). These very similar species are generally regarded as inseparable in the field. Male Cyprinella shiners in breeding condition (center) are known for their white-edged fins and vibrantly colored iridescent scales. (Vintage 35 mm image)

Fishes of the Lower Susquehanna River Watershed: Satinfin? Shiner — A possible breeding male **Satinfin Shiner** (Cyprinella analostanus). Traditional field marks of the Satinfin Shiner include dark pigment in all margins between the rays of the dorsal fin and a total of nine rays in the anal fin. (Vintage 35 mm image)

Fishes of the Lower Susquehanna River Watershed: Spotfin? Shiner — A possible breeding male **Spotfin Shiner** (Cyprinella spiloptera). *Traditional field marks of the Spotfin Shiner include dark pigment in the margins between the rays at the anterior end of the dorsal fin and a total of eight rays in the anal fin.*

Fishes of the Lower Susquehanna River Watershed: Common Carp — **Common Carp** (*Cyprinus carpio).*

Fishes of the Lower Susquehanna River Watershed: Cutlip Minnow — **Cutlip Minnow** (*Exoglossum maxillingua), also known as Cutlips Minnow*.

Fishes of the Lower Susquehanna River Watershed: Common Shiner — **Common Shiner** (Luxilus cornutus).

Breeding Male Common Shiner — A breeding male **Common Shiner** (*Luxilus cornutus)*.

Fishes of the Lower Susquehanna River Watershed: breeding male Common Shiner — A breeding male **Common Shiner** (*Luxilus cornutus)*.

Fishes of the Lower Susquehanna River Watershed: River Chub — **River Chub** (Nocomis micropogon).

Fishes of the Lower Susquehanna River Watershed: Golden Shiner — **Golden Shiner** (Notemigonus crysoleucas).

Fishes of the Lower Susquehanna River Watershed: Comely Shiner — **Comely Shiner** (*Notropis amoenus). (Vintage 35 mm image)*

Fishes of the Lower Susquehanna River Watershed: Emerald Shiner — **Emerald Shiner** (*Notropis atherinoides)*. (National Park Service image)

Fishes of the Lower Susquehanna River Watershed: Spottail Shiner — **Spottail Shiner** (*Notropis hudsonius*).

Fishes of the Lower Susquehanna River Watershed: Swallowtail Shiner — **Swallowtail Shiner** (Notropis procne).

Fishes of the Lower Susquehanna River Watershed: Rosyface Shiner — **Rosyface Shiner** (*Notropis rubellus). (Vintage 35 mm image)*

Fishes of the Lower Susquehanna River Watershed: Mimic Shiner — **Mimic Shiner** (*Notropis volucellus)*.

Fishes of the Lower Susquehanna River Watershed: Fathead Minnow — **Fathead Minnow** (Pimephales promelas).

Fishes of the Lower Susquehanna River Watershed: "Rosy-red Minnow", a xanthic morph of Fathead Minnow. — The **“Rosy-red Minnow”**, a xanthic (golden) morph of the Fathead Minnow (Pimephales promelas) first encountered among farm-raised baitfish populations, is commonly sold for home aquaria.

Fishes of the Lower Susquehanna River Watershed: Bluntnose Minnow — **Bluntnose Minnow** (Pimephales notatus).

Fishes of the Lower Susquehanna River Watershed: breeding male Bluntnose Minnow — A breeding male **Bluntnose Minnow** (Pimephales notatus).

Fishes of the Lower Susquehanna River Watershed: Eastern Blacknose Dace — **Eastern Blacknose Dace** (Rhinichthys atratulus).

Fishes of the Lower Susquehanna River Watershed: a breeding male Eastern Blacknose Dace — A breeding male **Eastern Blacknose Dace** (Rhinichthys atratulus).

Fishes of the Lower Susquehanna River Watershed: Longnose Dace — **Longnose Dace** (Rhinichthys cataractae).

Fishes of the Lower Susquehanna River Watershed: Juvenile Longnose and Blacknose Dace — On the bottom, a juvenile Longnose Dace (Rhinichthys cataractae). Above, two juvenile **Blacknose Dace** (Rhinichthys atratulus).

Fishes of the Lower Susquehanna River Watershed: Creek Chubs — **Creek Chubs** (Semotilus atromaculatus)

Fishes of the Lower Susquehanna River Watershed: Creek Chub — **Creek Chub** (*Semotilus atromaculatus)*

Fishes of the Lower Susquehanna River Watershed: Fallfish — **Fallfish** (Semotilus corporalis).

Family-Catostomidae

Carpiodes cyprinus (Quillback)

Catostomus commersoni (White Sucker)

Erimyzon oblongus (Creek Chubsucker)

Hypentelium nigricans (Northern Hogsucker)

Moxostoma anisurum (Silver Redhorse)-?

Moxostoma macrolepidotum (Shorthead Redhorse)

Fishes of the Lower Susquehanna River Watershed: Quillback — **Quillback** (*Carpiodes cyprinus)*. (United States Fish and Wildlife Service image by Brett Billings)

Fishes of the Lower Susquehanna River Watershed: White Sucker — **White Sucker** (*Catostomus commersoni).* (United States Fish and Wildlife Service image by Brett Billings)

Fishes of the Lower Susquehanna River Watershed: Creek Chubsucker — **Creek Chubsucker** (*Erimyzon oblongus). (Vintage 35 mm image)*

Fishes of the Lower Susquehanna River Watershed: Northern Hog Sucker — **Northern Hog Sucker** (Hypentelium nigricans).

Fishes of the Lower Susquehanna River Watershed: Shorthead Redhorse — **Shorthead Redhorse** (*Moxostoma macrolepidotum)*.

Order-Siluriformes

Family-Ictaluridae

Ameirus catus (White Catfish)

Ameirus natalis (Yellow Bullhead)

Ameirus nebulosus (Brown Bullhead)-includes Gronias nigrilabris (“Conestoga Blind Catfish”)

Ictalurus furcatus (Blue Catfish)-introduced

Ictalurus punctatus (Channel Catfish)-introduced

Noturus gyrinus (Tadpole Madtom)-PA Endangered

Noturus insignis (Margined Madtom)

Pylodictis olivaris (Flathead Catfish)-introduced

Fishes of the Lower Susquehanna River Watershed: White Catfish — **White Catfish** (*Ameirus catus).* (Smithsonian Environmental Research Center image by Robert Aguilar)

Fishes of the Lower Susquehanna River Watershed: Yellow Bullhead — An adult **Yellow Bullhead** (*Ameirus natalis).*

Fishes of the Lower Susquehanna River Watershed: juvenile Yellow Bullheads — Juvenile **Yellow Bullheads** (*Ameirus natalis).* (Vintage 35mm image)

**Brown Bullheads** (*Ameirus nebulosus).*

Hundreds of Brown Bullhead fry in a dense school. — Hundreds of juvenile **Brown Bullheads** (*Ameirus nebulosus)* in a densely packed school formation. To discourage predators, this behavior gives a mass group of dark-colored small fry the collective appearance of a large fish.

Schooling Juvenile Brown Bullheads — Juvenile **Brown Bullheads** (Ameirus nebulosus) less than one inch in length in constant motion vying for positions toward the center of the protective school. The constant motion of so many targets can confuse the visual and lateral line sensory capabilities of a predatory fish and render it unable to focus on a single target.

Fishes of the Lower Susquehanna River Watershed: Blue Catfish — **Blue Catfish** (*Ictalurus furcatus).* (United States Fish and Wildlife Service image by Brett Billings)

Fishes of the Lower Susquehanna River Watershed: Channel Catfish — **Channel Catfish** (*Ictalurus punctatus).* (United States Fish and Wildlife Service image by Brett Billings)

Fishes of the Lower Susquehanna River Watershed: juvenile Channel Catfish — A juvenile **Channel Catfish** (*Ictalurus punctatus).*

Fishes of the Lower Susquehanna River Watershed: Tadpole Madtom — **Tadpole Madtom** (*Noturus gyrinus)*. (United States Geological Survey image)

Fishes of the Lower Susquehanna River Watershed: Margined Madtom — **Margined Madtom** (Noturus insignis).

Fishes of the Lower Susquehanna River Watershed: Flathead Catfish — A juvenile **Flathead Catfish** (*Pylodictis olivaris)* among the Pothole Rocks at Conewago Falls.

Order-Characiformes

Family-Sarasalmidae

Colossoma or Piaractus species (Pacu species)-exotic

Piaractus brachypomus (Red-bellied Pacu)-exotic

Pygocentrus nattereri (Red-bellied Piranha)-exotic

Fishes of the Lower Susquehanna River Watershed: Red-bellied Pacu — As juveniles, these **Red-bellied Pacu** (Piaractus brachypomus) could be mistaken for Red-bellied Piranha (Pygocentrus nattereri). Both are tropical natives of South America’s Amazon River system. The former is sometimes sold in the aquarium and food trade using the name of the latter. Pacu are often called vegetarian piranhas. They possess teeth resembling human molars while piranhas have sharp-pointed teeth. As they age, Red-bellied Pacu soon lose their red color and attain lengths of two feet or more, quickly outgrowing most home aquaria. When no longer wanted as pets, pacu are oft times released into the ponds, lakes, and streams of the lower Susquehanna watershed. In 2009, an angler caught a Red-bellied Pacu while fishing in the Conestoga River in Manheim Township, Lancaster County, Pennsylvania. They’ve been found in Lake Placida on the campus of Elizabethtown College, also in Lancaster County. In autumn, pacu released into the waters of the Susquehanna basin are killed by falling temperatures. (United States Geological Survey image)

Order-Esociformes

Family-Esocidae

Esox americanus (Redfin Pickerel)-introduced

Esox niger (Chain Pickerel)

Esox reicherti (Amur Pike)-introduced

Esox lucius (Northern Pike)-introduced

Esox lucius x Esox reicherti (“Hybrid Pike”)-introduced-upper west branch species-186 fish stocked in Glendale Lake northwest of Altoona—last documented in 1976

Esox masquinongy (Muskellunge)-introduced

Esox lucius x Esox masquinongy (“Tiger Muskellunge”)-introduced

Fishes of the Lower Susquehanna River Watershed: Redfin Pickerel — **Redfin Pickerel** (*Esox americanus).* (Maryland Biodiversity Project image by Emilio Concari under license: CC BY-NC)

Fishes of the Lower Susquehanna River Watershed: Northern Pike — **Northern Pike** (*Esox lucius)*. (National Park Service image)

Fishes of the Lower Susquehanna River Watershed: Muskellunge — **Muskellunge** (*Esox masquinongy)*. (United States Fish and Wildlife Service image by Eric Engbretson)

Fishes of the Lower Susquehanna River Watershed: "Tiger Muskellunge" — The **“Tiger Muskellunge”** (Esox lucius x Esox masquinongy) is the sterile cross of a male Northern Pike and a female Muskellunge. These hybrids grow more vigorously under captive rearing conditions than their pure-bred parents. (United States Fish and Wildlife Service NCTC Freshwater Fishes Teaching Collection image by Matthew Patterson)

Order-Osmeriformes

Family-Osmeridae

Osmerus mordax (Rainbow Smelt)-introduced-upper Susquehanna/upper Juniata species

Fishes of the Lower Susquehanna River Watershed: Rainbow Smelt — **Rainbow Smelt** (*Osmerus mordax) were stocked as a forage and angling species in Harvey’s Lake in Lackawanna County (circa 1952) and Raystown Lake in Huntingdon County (pre-1988).* (NOAA Fisheries image by Katrina Mueller)

Order-Salmoniformes

Family-Salmonidae

Oncorhynchus kisutch (Coho Salmon)-introduced-upper Susquehanna species

Oncorhynchus mykiss (Rainbow Trout)-introduced

Oncorhynchus nerka (Sockeye Salmon)-introduced-upper Susquehanna species

Oncorhynchus tshawytscha (Chinook Salmon)-introduced-upper Susquehanna species

Salmo salar (Atlantic Salmon)-introduced

Salmo trutta (Brown Trout)-introduced

Salvelinus fontinalis (Brook Trout)

Salmo trutta x Salvelinus fontinalis (“Tiger Trout” hybrid)-introduced

Salvelinus namaycush (Lake Trout)-introduced-upper Susquehanna species

Salvelinus namaycush x Salvelinus fontinalis (“Splake” hybrid)-introduced

Fishes of the Lower Susquehanna River Watershed: Coho Salmon — **Coho Salmon** (*Oncorhynchus kisutch) were stocked (circa 1967) in Harvey’s Lake in Lackawanna County, PA.* (United States Department of the Interior Bureau of Land Management image)

Fishes of the Lower Susquehanna River Watershed: Rainbow Trout — **Rainbow Trout** (Oncorhynchus mykiss). (United States Fish and Wildlife Service image by Ryan Hagerty)

Fishes of the Lower Susquehanna River Watershed: Sockeye Salmon — **Sockeye Salmon** (*Oncorhynchus nerka) were stocked in Lake Winola west of Scranton (circa 1923), then in Harvey’s Lake near Wilkes-Barre in Lackawanna County, PA (circa 1967).* (United States Fish and Wildlife Service image)

Fishes of the Lower Susquehanna River Watershed: Chinook Salmon — Introductions of **Chinook Salmon** (*Oncorhynchus tshawytscha)* in the upper Susquehanna watershed near Scranton failed during the late nineteenth century and again circa 1940. (United States Fish and Wildlife Service image)

Fishes of the Lower Susquehanna River Watershed: Atlantic Salmon — **Atlantic Salmon** (*Salmo salar) were stocked (circa 1975) in Laurel Lake (Reservoir) in the Juniata River watershed in Mifflin County, PA.* (NOAA Fisheries image by Betty Holmes)

Fishes of the Lower Susquehanna River Watershed: Brown Trout — **Brown Trout** (*Salmo trutta).* (United States Fish and Wildlife Service image by Robert Pos)

Fishes of the Lower Susquehanna River Watershed: Brook Trout — **Brook Trout** (*Salvelinus fontinalis).* (United States Fish and Wildlife Service image)

"Late" Pleistocene Susquehanna Watershed — **The “Late” Pleistocene Susquehanna Watershed-**More than 11,000 years ago, during the last glacial maximum, when sea level was about 275 feet lower than it is today, there was no Chesapeake Bay, just a great Susquehanna River that flowed to the edge of the continental shelf and its mouth at Norfolk Canyon. It was a river draining taiga forests of pine, spruce, and fir, and it carried along the waters of all the present-day bay’s tributaries and more. The section of the river’s watershed we presently call the lower Susquehanna was, at the time, the upper Susquehanna watershed. Brook Trout and sculpins had the run of the river and its tributaries back then. And the entire watershed was a coldwater fishery, with limestone and other groundwater springs providing not refuge from summer heat, but a place to escape freezing water. (United States Geological Survey base image)

Fishes of the Lower Susquehanna River Watershed: "Tiger Trout" — The “Tiger Trout” (*Salmo trutta* x *Salvelinus fontinalis) is a hybrid occurring as a cross between two not-so-closely-related salmonids, a female Brown Trout (with 80 chromosomes) and a male Brook Trout (84 chromosomes).* These hybrids are a rarity in locations where the former has been introduced among native populations of the latter. The hatching success for these wild crosses seldom exceeds 5% and all offspring are sterile. In the nursery, quick heat treatment of fertilized eggs alters DNA replication and improves hatching success to 85%. The farm-raised trout often show “hybrid vigor” and grow rapidly. But, like those occuring by chance in nature, they are unable to reproduce. On several occasions, these hybrids have been recovered on the lower Susquehanna River in the fish lift facilities at Conowingo Dam, Maryland. (Public Domain image by Mathew Tyree)

"Tiger Trout" — One of several **“Tiger Trout”** (*Salmo trutta* x *Salvelinus fontinalis) caught by anglers during 2019 and 2020 in the Gunpowder River watershed in Baltimore County, Maryland. During the spring shad runs of both 2019 and 2021*, two of these hybrids were encountered on the nearby lower Susquehanna River in the fish lift facilities at Conowingo Dam, Maryland. (Image by baltimorefishing1 via iNaturalist under license CC BY-NC)

Fishes of the Lower Susquehanna River Watershed: Lake Trout — **Lake Trout** (*Salvelinus namaycush) have been stocked repeatedly in Harvey’s Lake in Lackawanna County, PA*. A population introduced into glacial Ostego Lake, the source of the Susquehanna at Cooperstown, NY, reproduce successfully but face increasing numbers of invasive Zebra Mussels (Dreissena polymorpha) on their spawning areas. (United States Geological Survey image)

Fishes of the Lower Susquehanna River Watershed: "Splake" — The **“Splake”** (Salvelinus namaycush x Salvelinus fontinalis) is a hybrid created in a fish hatchery by crossing a female Lake Trout and a male Brook Trout. To the disappointment of avid anglers, a “trophy-size” Brook Trout can instead turn out to be a “Splake”. These hybrids have been observed as they transit the fish lifts at the hydroelectric dams on the lower Susquehanna. (United States Fish and Wildlife Service image by Lindsey Adams)

Order-Beloniformes

Family-Belonidae

Strongylura marina (Atlantic Needlefish)

Tylosurus acus (Agujon)

Fishes of the Lower Susquehanna River Watershed: Atlantic Needlefish — **Atlantic Needlefish** (*Strongylura marina)* wander from the brackish waters of Chesapeake Bay into the fresh waters of its tributaries. They were probably a regular visitor to the lower Susquehanna prior to the construction of man-made dams. Since their installation during the late twentieth century, Atlantic Needlefish have occasionally been recorded using the fish lifts at the hydroelectric dams to ascend the river. (NOAA Southeast Fisheries Science Center image from the collection of Brandi Noble)

Order-Gadiformes

Family-Lotidae

Lota lota (Burbot)

Fishes of the Lower Susquehanna River Watershed: Burbot — The only record of the Burbot (Lota lota) in the lower Susquehanna is from Dauphin County prior to 1940. There is also an early record from Lycoming County. The Burbot reproduces in the Susquehanna watershed only in New York state where it is restricted to coldwater habitats. Though similar in appearance to the invasive Northern Snakehead, this indigenous fish is a member of the cod family, so it possesses chin barbels. (United States Fish and Wildlife Service image by Sam Stukel)

Order-Cyprinodontiformes

Family-Cyprinodontidae

Fundulus diaphanus (Banded Killifish)

Fundulus heteroclitus (Mummichog)

Fishes of the Lower Susquehanna River Watershed: Banded Killifish — **Banded Killifish** (*Fundulus diaphanus). (Vintage 35 mm image)*

Fishes of the Lower Susquehanna River Watershed: Mummichog — **Mummichogs** (*Fundulus heteroclitus)*. (Vintage 35 mm image)

Family-Poeciliidae

Gambusia affinis (Western Mosquitofish)-introduced

Gambusia holbrooki (Eastern Mosquitofish)-introduced

Fishes of the Lower Susquehanna River Watershed: Western Mosquitofish — **Western Mosquitofish** (Gambusia affinis), female (left) and male (right).

Fishes of the Lower Susquehanna River Watershed: Eastern Mosquitofish — **Eastern Mosquitofish** (Gambusia holbrooki), female (left) and melanistic male (right).

Gonopodium of Male Eastern Mosquitofish — The male **Eastern Mosquitofish** (Gambusia holbrooki) can be differentiated from the male Western Mosquitofish (G. affinis) by examination of the gonopodium, the elongated rays of the anal fin modified for sexual reproduction. The circled pair of prominent teeth on the first gonopodal ray of the male Eastern Mosquitofish seen here are absent on the male Western Mosquitofish.

Western Mosquitofish dorsal and anal fin element counts. — Counts of elements (segmented rays and spines) in the dorsal and anal fins of mosquitofish can sometimes be used to determine the species. This female Western Mosquitofish (Gambusia affinis) shows 7 elements in the dorsal fin and 10 in the anal fin…

Eastern Mosquitofish dorsal and anal fin element counts. — …while the **Eastern Mosquitofish** (Gambusia holbrooki) will usually possess 8 and 11 respectively.

Fishes of the Lower Susquehanna River Watershed: Mosquitofish — Gravid female Mosquitofish (Gambusia species) gather in 2 to 3 inches of vegetated water to give birth to their live young.

Order-Gasterosteiformes

Family-Gasterosteidae

Apeltes quadracus (Fourspine Stickleback)

Culaea inconstans (Brook Stickleback)–introduced-upper Juniata-PA Candidate

Fishes of the Lower Susquehanna River Watershed: Fourspine Stickleback — **Fourspine Stickleback** (*Apeltes quadracus).* (Smithsonian Environmental Research Center image by Robert Aguilar)

Order-Scorpaeniformes

Family-Cottidae

Cottus bairdi (Mottled Sculpin) ?

Cottus caeruleomentum (Blue Ridge Sculpin)

Cottus cognatus (Slimy Sculpin)

Cottus girardi (Potomac Sculpin)

Fishes of the Lower Susquehanna River Watershed: Blue Ridge Sculpin — **Blue Ridge Sculpin** (Cottus caeruleomentum). (United States Geological Survey image)

Fishes of the Lower Susquehanna River Watershed: Slimy Sculpin — **Slimy Sculpin** (*Cottus cognatus*). (United States Fish and Wildlife Service image by Ryan Hagerty)

Fishes of the Lower Susquehanna River Watershed: Potomac Sculpin — **Potomac Sculpin** (*Cottus girardi).* (United States Fish and Wildlife Service image by Ryan Hagerty)

Order-Perciformes

Family-Percichthydae

Morone americana (White Perch)

Morone chrysops (White Bass)-introduced

Morone saxatilis (Striped Bass)

Morone saxatilis x Morone chrysops (“Hybrid Striped Bass”)-introduced

Fishes of the Lower Susquehanna River Watershed: White Bass — **White Bass** (*Morone chrysops).* (United States Fish and Wildlife Service image)

Fishes of the Lower Susquehanna River Watershed: Striped Bass — **Striped Bass** (*Morone saxatilis). (United States Fish and Wildlife Service image by Ryan Hagerty)*

Fishes of the Lower Susquehanna River Watershed: "Hybrid Striped Bass" — A **“Hybrid Striped Bass”** (Morone saxatilis x Morone chrysops) is a hatchery-produced cross of a male Striped Bass and a female White Bass, or of a female Striped Bass and a male White Bass. The former is sometimes called a “Sunshine Bass”, the latter a “Palmetto Bass”. These hybrids are able to withstand higher water temperatures and lower dissolved oxygen levels than pure-bred Stripers, hence they are better suited for aquaculture and nursery rearing. Because female Striped Bass produce far more eggs than can female White Bass, the cross yielding the “Palmetto Bass” is favored by hatchery operators. In the lower Susquehanna valley, “Hybrid Striped Bass” are raised commercially at a fish farm just downriver from Conewago Falls on Brunner Island in York County. (United States Fish and Wildlife Service image by Ryan Hagerty)

Family-Centrarchidae

Ambloplites rupestris (Rock Bass)-introduced

Enneacanthus gloriosus (Bluespotted Sunfish)

Lepomis auritus (Redbreast Sunfish)

Lepomis cyanellus (Green Sunfish)-introduced

Lepomis gibbosus (Pumpkinseed)

Lepomis macrochirus (Bluegill)-introduced

Lepomis microlophus (Redear Sunfish)-introduced

Micropterus dolomieu (Smallmouth Bass)-introduced

Micropterus salmoides (Largemouth Bass)-introduced

Pomoxis annularis (White Crappie)-introduced

Pomoxis nigromaculatus (Black Crappie)-introduced

Fishes of the Lower Susquehanna River Watershed: Rock Bass — **Rock Bass** (*Ambloplites rupestris)*. (United States Fish and Wildlife Service image)

Fishes of the Lower Susquehanna River Watershed: juvenile Rock Bass — A juvenile **Rock Bass** (Ambloplites rupestris).

**Blue-spotted Sunfish** (*Enneacanthus gloriosus).* (Maryland Biodiversity Project image by Emilio Concari, under license: CC BY-NC)

Fishes of the Lower Susquehanna River Watershed: Redbreast Sunfish — **Redbreast Sunfish** (*Lepomis auritus).* (United States Fish and Wildlife Service image by Ryan Hagerty)

Fishes of the Lower Susquehanna River Watershed: Juvenile Redbreast Sunfish — Juvenile **Redbreast Sunfish** (*Lepomis auritus).* (United States Fish and Wildlife Service image by Ryan Hagerty)

Fishes of the Lower Susquehanna River Watershed: Bluegill — **Bluegill** (Lepomis macrochirus).

Fishes of the Lower Susquehanna River Watershed: a juvenile Bluegill — A juvenile **Bluegill** (Lepomis macrochirus).

Fishes of the Lower Susquehanna River Watershed: "Hybrid Sunfish" — **“Hybrid Sunfish”** (*Lepomis macrochirus x Lepomis cyanellus) are produced in fish hatcheries by crossing a male Bluegill with a female Green Sunfish.* The offspring, of which ninety percent or more are male, grow quickly to an attractive size for anglers. Other Lepomis hybrids are possible in the wild, especially where non-native sunfish have been introduced among native species. (United States Fish and Wildlife Service image by Sam Stukel)

Fishes of the Lower Susquehanna River Watershed: Green Sunfish — **Green Sunfish** (Lepomis cyanellus).

Pumpkinseed and Green Sunfish at nests. — A **Pumpkinseed** (Lepomis gibbosus) defends its nest to the lower left while a **Green Sunfish** (Lepomis cyanellus) protects its scrape to the upper right.

Fishes of the Lower Susquehanna River Watershed: Redear Sunfish — **Redear Sunfish** (*Lepomis microlophus).* (United States Fish and Wildlife Service image by Ryan Hagerty)

Fishes of the Lower Susquehanna River Watershed: Smallmouth Bass — **Smallmouth Bass** (*Micropterus dolomieu). (Vintage 35 mm image)*

Fishes of the Lower Susquehanna River Watershed: Largemouth Bass — **Largemouth Bass** (Micropterus salmoides).

Fishes of the Lower Susquehanna River Watershed: juvenile Largemouth Bass — A juvenile **Largemouth Bass** (Micropterus salmoides).

Fishes of the Lower Susquehanna River Watershed: Black Crappie — **Black Crappie** (*Pomoxis nigromaculatus).* (United States Fish and Wildlife Service image by Eric Engbretson)

Family-Percidae

Etheostoma blennioides (Greenside Darter)-introduced

Etheostoma flabellare (Fantail Darter)

Etheostoma olmstedi (Tessellated Darter)

Etheostoma sellare (Maryland Darter)-Federally Endangered/MD Endangered

Etheostoma zonale (Banded Darter)-introduced

Percina bimaculata (Chesapeake Logperch)-PA Threatened/MD Threatened

Percina peltata (Shield Darter)

Perca flavescens (Yellow Perch)

Sander vitreus (Walleye)-introduced

Fishes of the Lower Susquehanna River Watershed: Greenside Darter — **Greenside Darter** (*Etheostoma blennioides).*

Fishes of the Lower Susquehanna River Watershed: Fantail Darter — **Fantail Darter** (*Etheostoma flabellare).* (United States Fish and Wildlife Service image by Ryan Hagerty)

Fishes of the Lower Susquehanna River Watershed: Tessellated Darter — **Tessellated Darter** (*Etheostoma olmstedi).*

Fishes of the Lower Susquehanna River Watershed: juvenile Tessellated Darter. — A juvenile **Tessellated Darter** (Etheostoma olmstedi).

Fishes of the Lower Susquehanna River Watershed: Maryland Darter — **Maryland Darter** (*Etheostoma sellare*), a specimen collected in October, 1985. This Federally Endangered Species was last seen in 1988 in Deer Creek, a Susquehanna River tributary in Harford County, Maryland. (Smithsonian Environmental Research Center image by Robert Aguilar: under license CC BY-NC)

Fishes of the Lower Susquehanna River Watershed: Banded Darter — **Banded Darter** (*Etheostoma zonale). (Vintage 35 mm image)*

Fishes of the Lower Susquehanna River Watershed: Banded Darter and Tessellated Darter — A **Banded Darter** (*Etheostoma zonale)* on top and, for comparison, a Tessellated Darter (*Etheostoma olmstedi)* on the bottom.

Fishes of the Lower Susquehanna River Watershed: Chesapeake Logperch — **Chesapeake Logperch** (Percina bimaculata), a species first described by Samuel Steman Haldeman in 1842 and 1844. Long considered to be synonymous with the widespread Common Logperch (Percina caprodes), recent mitochondrial DNA analysis proved it to be a valid species unique to the lower Susquehanna and other tributaries of the upper Chesapeake Bay. (United States Fish and Wildlife Service Image by Kayt Jonsson)

Fishes of the Lower Susquehanna River Watershed: Shield Darter — **Shield Darter** (*Percina peltata). (United States Fish and Wildlife Service Image by Kayt Jonsson)*

Fishes of the Lower Susquehanna River Watershed: Yellow Perch — **Yellow Perch** (*Perca flavescens).* (United States Fish and Wildlife Service image by Brett Billings)

Fishes of the Lower Susquehanna River Watershed: Walleye passing York Haven Dam Fish Passage — **Walleye** (*Sander vitreus) swimming by* the counter’s window at the York Haven Dam Fish Passage located just upstream from Conewago Falls.

Order-Cichliformes

Family-Cichlidae

Tilapia aurea (Blue Tilapia)-exotic

Fishes of the Lower Susquehanna River Watershed: Blue Tilapia — During the early 1980s, **Blue Tilapia** (*Tilapia aurea)* were raised at a fish farm on Brunner Island just downstream of Conewago Falls. During the colder months, the facility used warm water from the coal-fired steam-electric generator there to increase the temperature in the grow-out channels. Anglers enjoyed an occasional catch of a colorful Blue Tilapia that had escaped into the Susquehanna. During the winter, cold water was fatal to both tilapia in the river and, if the power plant experienced a shutdown, those in the fish culture facility. As a result, efforts to raise tilapia were abandoned in favor of growing cold-tolerant species including Channel Catfish, Hybrid Striped Bass, and ornamental Goldfish. (United States Geological Survey image by Howard Jelks)

Order-Anabantiformes

Family-Channidae

Channa argus (Northern Snakehead)-introduced

Fishes of the Lower Susquehanna River Watershed: Northern Snakehead — The **Northern Snakehead** (*Channa argus), an introduced species from eastern Asia, was f*irst reported in the Susquehanna watershed near the river’s mouth and in the nearby Octararo Creek in Cecil County, Maryland in 2016. During 2018, it was found upstream in the river to Conowingo Dam and had advanced on the Octararo Creek into Pennsylvania. During 2019, the Northern Snakehead was found in Deer Creek in Harford County, Maryland, the last known habitat of the endangered Maryland Darter. (United States Fish and Wildlife Service image)

SOURCES

Argent, D. G., J. R. Stauffer, Jr., R.F. Carline, C. P. Ferreri, and A. Shiels. 1998. Updated July 7, 2011. Fishes: Review of Status in Pennsylvania. pp. 177-202. In: Inventory and Monitoring of Biotic Resources in Pennsylvania. Proceedings of the First Conference of the Pennsylvania Biological Survey. University Park, PA.

Bean, Tarleton H. 1893. The Fishes of Pennsylvania: with Descriptions of the Species and Notes on their Common Names, Distribution, Habits, Reproduction, Rate of Growth, and Mode of Capture. E. K. Myers. Harrisburg, PA.

Denoncourt, Robert F., Charles H. Hocutt, and Jay R. Stauffer, Jr. 1975. “Additions to the Pennsylvania Ichthyofauna of the Susquehanna River Drainage.” Proceedings of the Academy of Natural Sciences of Philadelphia. 127:9. pp.67-69.

Haldeman, Samuel Steman. 1844. “Natural History of Lancaster County: Pisces—Fishes”. I. Daniel Rupp’s History of Lancaster County. Gilbert Hills. Lancaster, PA. pp.472-474.

Maryland Natural Heritage Program. 2016. List of Rare, Threatened, and Endangered Animals of Maryland. Maryland Department of Natural Resources, 58 Taylor Avenue, Annapolis, MD 21401.

Normandeau Associates, Inc. 2012. Shortnose and Atlantic Sturgeon Life History Studies—Conowingo Hydroelectric Project. Final Study Report for Exelon Energy Corporation.

Pennsylvania Natural Heritage Program. PNHP Species Lists. www.naturalheritage.state.pa.us/Species.aspx Accessed August 14, 2019.

Page, Lawrence M., and Brooks M. Burr. 1991. A Field Guide to Freshwater Fishes. Houghton Mifflin Company, New York, NY.

St. Pierre, Richard. 1999. Restoration of American Shad to the Susquehanna River, Annual Progress Report 1998. Susquehanna River Anadromous Fish Restoration Cooperative.

Stauffer, Jacob. 1869. “Ichthyology”. J. I. Mombert’s An Authentic History of Lancaster County. J. E. Barr and Company. Lancaster, PA. pp.576-579.

Stauffer, Jay R., Jr., Robert W. Criswell, Douglas P. Fischer. 2016. The Fishes of Pennsylvania. Cichlid Press. El Paso, TX.

Steiner, Linda. 2000. Pennsylvania Fishes. Pennsylvania Fish and Boat Commission. Harrisburg, PA.

United States Geological Survey Nonindigenous Aquatic Species Database. http://nas.er.usgs.gov Accessed August 18, 2019.