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FISHERIES

Sea-Run l Freshwater l Marine

Sea-Run Fish

The Penobscot River watershed is home to 11 species of sea-run (anadromous or catadromous) fish. Many of these species supplied commercial fisheries in the past and a number continue to sustain recreational or commercial value. Removing the dams and restoring the river is expected to benefit many of these species, although the effects on individual species are difficult to determine. No ecosystem can be returned to some historic condition, because much has changed in the watershed in the 100+ years that these fish have been absent from the river. Reconstructing historic populations, evaluating available habitat, and studying restoration of other rivers such as the Kennebec can provide some indication of how fisheries may change in the Penobscot in the future.

Alewife, American eel, American shad, Atlantic salmon, Atlantic & shortnose sturgeon, Atlantic tomcod, blueback herring, rainbow smelt, sea lamprey, striped bass

Alewife Alosa pseudoharengus and Blueback herring Alosa aestivalis
These two species of river herring live in large schools in the ocean and swim up freshwater rivers (usually in mid-late May in the Penobscot basin) to spawn in ponds and lakes in the spring. The species ranges from Newfoundland to South Carolina. Blueback herring spawn later than alewives in the moving currents of rivers and streams. Adults migrate back downstream shortly after spawning and juveniles also leave for the ocean in summer and fall. Historically, hundreds of thousands of alewives were caught in Penobscot River commercial fisheries. Current landings statewide are around one million pounds. Today, spawning runs continue in the Souadabscook Stream and other tributaries of the Penobscot.

Contact:
Tom Squiers, Maine Department of Marine Resources

American eel Anguilla rostrata
American eel are commercially harvested in Maine and throughout their range, although data on harvest are incomplete. There is a glass eel (elver) and yellow eel (silver eel) fishery in Maine, although the catch has declined due to regulation and poor market conditions. In 2003, both the International Eel Symposium and the Great Lakes Fisheries Commission declared concern for the health of American eel populations (PDF). Maine conducts an annual young-of-the-year survey abundance survey.

References:
American Eel (Anguilla rostrata) Species Management Plan (DMR and DIFW 1996)

Interstate Marine Fisheries Management Plan for American Eel (ASMFC 1999). PDF

Interstate Marine Fisheries Management Plan for American Eel Review (ASMFC 2005). PDF

Contact:
Gail Wipplehauser, Maine Department of Marine Resources

American shad Alosa sapidissima
Shad are born in the upper reaches and tributaries of freshwater rivers from northern Florida to Labrador and spend four to five years in the ocean before returning to freshwater to spawn. Shad travel inland up to 90 miles and historically ranged as far as Millinocket in the Penobscot; in fact, most of the ideal spawning habitat is above the Milford Dam. Shad spawn at night, in shallow flowing water with moderate currents. Eggs are released in the water column and drift downstream before hatching. The young feed on microscopic plants and zooplankton in the water. Their movements are cued by light and other visual stimuli; schooling shad are easily slowed by changes in the river around them. The Penobscot migration peaks in June. The historic shad population, estimated at around two million, supported the dominant commercial fishery in the Penobscot River in the nineteenth century.

References:
Penobscot River Shad and Alewife Restoration Potential (DMR, 1984)

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic): American Shad (USFWS, 1986). PDF

American Shad Management Plan (DMR, 1987)

A Strategic Plan to Restore American Shad (Alosa sapidissima) to the Penobscot River, Maine (USFWS, PIN, DMR, DIFW, 2001)

The Founding Fish (John McPhee, 2002)

Atlantic salmon Salmo salar
Atlantic salmon are an important part of Native American culture and historically were an important food resource. Before 1830, an estimated 50,000 to 75,000 salmon returned to the Penobscot, the largest salmon run in Maine and the second largest in the U.S. The late 1800s to early 1900s marked the height of the commercial salmon fishery in the Penobscot, when the estuary bristled with weir nets (MWIC, 1967) and Charles Atkins towed salmon up the Orland River to his hatchery at Craig Brook (founding the first federal fish hatchery in the nation). By the mid-1900s, the cumulative effects of heavy fishing, increasing pollution, and dam construction depleted the fishery and instigated an aggressive restoration program that continues today.

Salmon were fished in the river (until 1947) and offshore (until early 1990s), off the coast of Greenland (until 1996) and by recreational anglers (until 1999).

Today, the population is supported by the half a million smolts that are raised at Green Lake and Craig Brook National Fish Hatcheries and released into the Penobscot River every year. Fisheries scientists estimate that the Penobscot could potentially support 8,000 to 12,000 returning adults. Smolts are released in the spring at Mattawamkeag, Milo, and Howland. A team of researchers from the University of Maine, NOAA, and USGS have been tracking both hatchery and wild smolts to follow their migrations. They are trying to figure out the best way to stock fish so more of them make it to sea and back.

Eggs are laid in "redds" dug into shallow gravel in the river and tributaries. The eggs hatch in April. Young salmon stay in fresh water (known as "fry" and "parr" during these stages) for one to several years, until they grow large enough to migrate in the spring. As the days get longer and warmer, the fish, now approaching 11 centimeters in length, undergo internal and external changes as they prepare to enter salt water. They lose their parr stripes and take on the silvery shine of a schooling fish. The cells in their gills undergo chemical changes so they can tolerate salt water, a process controlled by hormones. The young, sea-ready salmon are now smolts (although scientists still have difficulty defining a 'smolt'). Smolting is a size-related, developmental event.

Smolts migrate downstream in late April-early May, depending on their size and light and temperature conditions in the water. They take their time swimming through the freshwater portion of the river, resting during the day and moving at night. When they hit salt water, they increase speed (up to 25 miles per hour) and travel day and night, staying near the surface. Ninety percent migrate over a two-week period (S. McCormick, seminar, 3/20/06). According to NOAA-Fisheries, which operates an array of hydroacoustic sensors that detect tagged migrating fish, roughly 55% of them successfully reach the Gulf of Maine; 85% make it past Verona Island and 55% past Rockland. It is not known if that percentage is the natural success rate, although it is similar to the success rates of other rivers like the Narraguagus and Canada's Miramichi. Many factors could be affecting smolt survival in the estuary, including physical damage or stress from passing through dams or being handled, chemicals that affect hormones during smolting, and predation.

After they pass the last line of buoys, the young salmon head out through the Gulf of Maine and make their way to the Greenland coast, but most of their time in the ocean is a "black box." Ocean predators include tuna, cod, bluefish, seals, and sea lamprey. Penobscot salmon usually spend two years at sea before heading home to spawn. The fish, now adults, enter the river between March and November, with a peak migration during June and July (wild fish tend to return in spring; hatchery fish return in fall). Spawning occurs in October and November in moving water over coarse gravel or rubble. Unlike their Pacific cousins, Atlantic salmon do not die after spawning, and can return year after year to reproduce.

In 2005, 1,323 salmon returned to the Penobscot River, accounting for 81 percent of the total return in the U.S. The majority of the returning fish were born in hatcheries, but a small number were of natural origin (USASAC, 2005).

The Recreational Fishery
Recreational fishing for salmon began in earnest on the Penobscot in 1880. The Penobscot River was one of 16 Maine rivers closed to Atlantic salmon fishing in 1999; the Maine Atlantic Salmon Commission is currently considering reopening the river for a short catch-and-release season, possibly as soon as fall 2006. A hearing on the recreational season will be held on May 25, 2006 at Holden Elementary School. http://www.maine.gov/asc/

References:
Penobscot River Classification Report (Maine Water Improvement Commission, 1967).

Final Recovery Plan (U.S. Fish and Wildlife Service, 2005). PDF

Annual Reports of the U.S. Atlantic Salmon Assessment Committee (USASAC)
1999 Annual ReportPDF
2000 Annual Report PDF
2001 Annual Report
2002 Annual Report PDF
2003 Annual Report PDF
2004 Annual Report PDF
2005 Annual Report PDF

Atlantic Salmon Status Review

Contact:
Joan Trial, Maine Atlantic Salmon Commission
John Kocik, NOAA-Fisheries

Atlantic sturgeon Acipenser oxyrinchus oxyrinchus
Shortnose sturgeon Acipenser brevirostrum
Two species of sturgeon, the Atlantic and shortnose, are known to have inhabited the Penobscot. Sturgeon have survived one hundred million years since the Cretaceous period ("When dinosaurs were walking around in shallow water, they were stepping on sturgeon"). We know from archeological sites at Hirundo, Gut Island, and Eddington Bend that Native Americans utilized sturgeon. There was never a large commercial fishery for sturgeon in the river, although after the Kennebec population was depleted by harvesting in the 1800s, the Penobscot River supported half of the Maine sturgeon fishery.

The Penobscot River is the northern limit for Atlantic sturgeon, which can be found in coastal rivers along the East Coast between Maine and Florida. Atlantic sturgeon are a late-maturing species that can grow up to 14 feet long. Sturgeon spawn in fast-moving water over rocky substrate, in deep pools below the first sets of rapids. Most likely, sturgeon historically ranged as far up the Penobscot as Milford, where natural falls and ledges prevented them from migrating any farther upstream. Shortnose sturgeon spawn in water between 9 and 15 degrees Celsius (April to June) and Atlantic sturgeon spawn later, at water temperatures of 18-24 degrees Celsius. The young hatch at the spawning site and stay in fresh water; juveniles move downstream into the estuary. Shortnose sturgeon remain in the estuary as adults, but Atlantics move out into the ocean for several to many years before returning home to fresh water to reproduce. Sturgeon are primarily bottom-dwelling fish and overwinter in deep pools. They eat small crustaceans and fish.

Shortnose sturgeon were listed as endangered in 1967 (before the Endangered Species Act). The status of Atlantic sturgeon is currently under re-evaluation.

References:
Status Review of Atlantic Sturgeon (U.S. Fish and Wildlife Service and NOAA, 1998). PDF

Contact:
Stephen Fernandes, University of Maine
Tom Squiers, Maine Department of Marine Resources

Atlantic tomcod (frostfish) Microgadus tomcod
Atlantic tomcod are found in coastal, brackish waters from Labrador and Newfoundland to Virginia. They sometimes occur in fresh water and are landlocked in several lakes. Tomcod appear in mid-winter (December-February) to spawn in shallow waters of estuaries and stream mouths. Eggs hatch in the summer and juveniles remain in low-salinity parts of the estuary. They feed mostly on small crustaceans (especially shrimps and amphipods), worms, small mollusks, squids, and juvenile fish.

References:
Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (North Atlantic): Atlantic Tomcod (U.S. Army Corps of Engineers and U.S. Fish and Wildlife Service, 1987). PDF

Rainbow smelt Osmerus mordax
At six to eight inches long, rainbow smelt are the smallest of Maine's anadromous fish. They range from Labrador to New Jersey and migrate into the Penobscot in April, cued by the lengthening days. Some smelt remain in harbors and streams of the lower river through the fall. They are harvested in spring with dip nets placed in tributaries of the Penobscot. Smelt feed on zooplankton, shrimps, worms, and small fish; they in turn are eaten by striped bass, bluefish, and birds.

References:
Pellerin, J.C. Smelt Management Plan. (ME Dept. of Inland Fisheries & Wildlife, 2001). PDF

Sea lamprey Petromyzon marinus
Sea lamprey range from Greenland to Florida. They spawn in June in rapid, fresh water over gravelly, rocky substrate. They can travel up to 200 miles inland, and are able to use their suction-like mouths to ascend shallow falls. Adults die after spawning. The young spend eight or more years maturing in freshwater streams and rivers, and migrate downstream in November and December to spend several years in the sea as adults.

References:
Fishes of the Gulf of Maine (Bigelow and Schroeder, 1948)

Sea Lamprey (F.W. Kircheis, 2004). PDF

Striped bass Morone saxatilis
Striped bass range the entire coast of Maine, migrating north in May and entering coastal rivers and estuaries until October, when they return south, most of them to the Chesapeake Bay region. They do not spawn in the Penobscot.

References:
Fishes of the Gulf of Maine (1948)

Amendment 6 to the Interstate Fishery Management Plan for Atlantic Striped Bass (ASMFC, 2003)

FRESHWATER FISH

Maine is home to 69 species of fish that spend at least part of their life in fresh water; 70% of them are native. The following species have been documented in the Penobscot River watershed.

Brown bullhead Ameiurus nebulosus
Maine's only native species of catfish, found throughout the watershed, commonly in large lakes at lower elevations.

Cusk Lota lota
Freshwater member of the cod family. Widespread but uncommon, found in large lakes and larger sections of the river.

Minnows
About 60% of Maine’s minnow species are likely native to the state. Most of the species occurring in Maine are considered both lake and stream dwellers. Six species are relatively common and broadly distributed in the state and the Penobscot watershed: the golden shiner (Notemigonus crysoleucas), creek chub (Semotilus atromaculatus), common shiner (Luxilus cornutus), fallfish (Semotilus atromaculatus), northern redbelly dace (Phoxinus eos) and blacknose dace (Rhinichthys atratulus). Other minnows in the Penobscot basin include:

Lake chub Couesius plumbeus (Present in the northwestern watershed.)
Pearl dace Margariscus margarita
Blackchin shiner Notropis heterodon
Blacknose shiner Notropis heterolepis
Spottail shiner Notropis hudsonius (Found in streams in lower watershed.)
Fathead minnow Pimephales promelas
Finescale dace Phoxinus neogaeus
Longnose dace Rhinichthys cataractae (In Piscataquis drainage.)

Central mudminnow Umbra limi
Not a true minnow; first recorded in Maine in 1999 from the Orono–Old Town area. It probably represents a release from a local bait dealer.

Yellow perch Perca flavescens
Native but introduced to many lakes where it did not naturally occur, yellow perch are now common and abundant.

Chain pickerel Esox niger
Native only to the southwestern part of the state, chain pickerel were introduced into the Penobscot basin in the early 1800s. Today, the chain pickerel is the sixth most common species, in terms of number of lakes inhabited. It is found in lakes of all sizes, but rarely occurs at elevations higher than 1,000 feet.

Northern pike Esox lucius
Northern pike were illegally introduced into the Belgrade Lakes in the 1970s, and are now present in at least 16 lakes in the Kennebec, Androscoggin, and coastal river drainages. Recently, pike have been documented in Pushaw Lake, opening up the possibility that they could expand into the mainstem of the Penobscot River and tributaries. These newest populations have been derived from illegal transport or by out-migration from lakes were they have become established. Pike are voracious predators on other fishes, and their presence may influence populations of native fishes.
http://www.maine.gov/ifw/fishing/illegalstocking.htm

Arctic char Salvelinus alpinus
Maine is the only state with native populations of Arctic char, one of two freshwater species listed as of Special Concern by the Maine Department of Inland Fisheries and Wildlife. It is the only freshwater fish that is considered endemic to the New England states (meaning it is found nowhere else in the world). Arctic char are found in lakes in the East and West Branch watersheds.

Lake trout (togue) Salvelinus namaycush
Lake trout are characteristic of larger, deep, less productive lakes.

Lake whitefish Coregonus clupeaformis
Native but uncommon, found in northwestern parts of the watershed.

Landlocked salmon Salmo salar sebago
Native, but virtually all current populations are the result of past and/or present stocking.

Brown trout Salmo trutta
Native to Europe; introduced in Maine in early 1900s; rare in watershed.

Rainbow trout Oncorhynchus mykiss

Brook trout Salvelinus fontinalis
Maine possesses the most significant brook trout resource in the northeastern U.S. and the species is found throughout the watershed. Natural distribution of brook trout is limited by water temperature, so in warmer lakes populations are often maintained by stocking. Trout is usually a symbol of clean, cold waters and pristine habitat.
Brook Trout Management Plan (Bonney, 2001).

Splake Salvelinus hybrid 1
Found in the West Branch, East Branch, Piscataquis drainages.

Slimy sculpin Cottus cognatus
Found in riffle areas in cold streams and lakes.

Sticklebacks
All four North American sticklebacks are present in the Penobscot watershed. The threespine (Gasterosteus aculeatus) and ninespine (Pungitius pungitius) sticklebacks are relatively common, whereas the fourspine stickleback (Apeltes quadracus) and brook stickleback (Culaea inconstans) are much rarer.

White sucker (common sucker) Catostomus commersoni
The second most common fish species in Maine lakes, being relatively more common at lower elevations and in larger systems.

Longnose sucker Catostomus catostomus
Less common, restricted to western and northern areas above 300 feet in elevation.

Sunfishes
Two native species of sunfish, the redbreast sunfish (Lepomis auritus) and the pumpkinseed (Lepomis gibbosus) are found throughout the watershed. Green sunfish (Lepomis cyanellus) were recently introduced at one location in the watershed and are not widespread.

Smallmouth bass Micropterus dolomieu
Smallmouth bass were introduced to the Penobscot in the 1800s and are now the top resident gamefish in the lower river. Largemouth bass Micropterus salmoides are also present in the watershed, and black crappie (Pomoxis nigromaculatus) have been documented in the southern part of the watershed.
http://www.maine.gov/ifw/fishing/reports/bassmanagement.htm

White perch Morone Americana
Native to coastal regions and low gradient river segments with direct coastal access; now present throughout the watershed.

References:
PEARL data on species distributions

Fish Assemblages in Maine Rivers (Yoder et al., 2005). PDF

Maine Department of Inland Fisheries and Wildlife Species Management Plans

MARINE FISHES OF PENOBSCOT ESTUARY AND BAY

Penobscot Bay plays an important role in the early life history of fish inhabiting the central coast of Maine by offering habitat for larval fish, including snailfishes, sculpins, sand lance, winter flounder, plaice, seasnail, rock gunnel, and Atlantic cod (Lazzari, 2001). Adult fish are dominated by winter flounder, threespined stickleback, lumpfish, and grubby. Other widespread fish species include sand lance and sea raven. Crustaceans include American lobster, sevenspine bay shrimp, green crab, and northern shrimp. Hake, pollock, and rockling can also be found. In particular, shallow areas with vegetation (eelgrass) have greater species richness and higher abundances of fishes and decapod crustaceans (Lazzari and Tupper, 2002).

Dynamics of larval fish abundance in Penobscot Bay, Maine (Lazzari, 2001). PDF

Importance of shallow water habitats for demersal fishes and decapod crustaceans in Penobscot Bay, Maine (Lazzari and Tupper, 2002). Environmental Biology of Fishes Vol. 63, no. 1, pp. 57-66.

Penobscot Bay Juvenile Fish Survey