How many types of fish are in Maine? The clearest official count is 71 fish species that spend at least part of their life cycle in freshwater, according to Maine Natural Areas Program. The figure covers freshwater-associated fish—not every species in Maine’s estuaries, coastal waters, Gulf of Maine, or offshore waters.
That distinction is essential because Maine’s inland and marine agencies maintain separate fish resources, while sea-run species move between both environments. “Types” can also mean species, families, habitats, migration patterns, or fishing categories, so the most useful answer depends on the scope.
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Key takeaways
- Maine has 71 fish species that spend at least part of their life cycle in freshwater.
- The 71 freshwater-associated species belong to 45 genera and 18 families.
- Approximately 49 of the 71 species—about 70%—are identified as native to Maine, although native status does not mean a species historically lived throughout the entire state.
- Maine’s Department of Marine Resources identifies 12 sea-run, or diadromous, fish species that use both freshwater and saltwater during their life cycles.
- No reviewed official source provides one standardized total for every fish species found in Maine’s freshwater, estuarine, coastal, offshore, seasonal, and transient habitats.
What is the official number of fish species in Maine?
The official number most readers should use is 71 freshwater-associated fish species. According to the Maine Natural Areas Program’s freshwater ecology report, “In Maine there are currently 71 fish species that spend at least part of their life cycle in freshwaters.” The report’s publication year is not stated in the accessed document.
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1Repair Windows errors before they cause bigger problems2Scan for outdated or missing drivers - takes under a minute3Clear out junk files and repair common Windows errorsThe freshwater qualification matters. Maine has extensive marine and estuarine habitat, and some fish migrate between the ocean and inland waters. Therefore, “Maine has 71 fish species” is too broad: the documented figure does not establish a complete count for every fish species that may occur anywhere in Maine’s marine, coastal, estuarine, and offshore waters.
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How many fish species are included in the 71-species count?
The 71 species in the authoritative freshwater count are grouped into 45 genera and 18 families. The carp-and-minnow family, Cyprinidae, is the most species-rich family in that count, with 21 species.
| Measure | Reported figure | What the figure means |
|---|---|---|
| Freshwater-associated fish species | 71 species | Fish spending at least part of their life cycle in Maine freshwater |
| Genera represented | 45 genera | Broader taxonomic groups containing the 71 species |
| Families represented | 18 families | Still broader taxonomic groups containing the 45 genera |
| Most species-rich family | Cyprinidae, 21 species | The carp-and-minnow family has the largest representation in the freshwater count |
Does Maine have more than 71 fish species?
Probably, if “fish in Maine” includes all marine and offshore species, but the reviewed official sources do not provide one unified, standardized statewide total. The 71-species figure covers fish associated with freshwater, while the Maine Department of Marine Resources maintains a separate marine species-information directory.
Combining separate freshwater and marine lists would also require careful taxonomic and geographic review. A species may appear in both types of resource because it uses more than one habitat, and seasonal or occasional visitors may be treated differently from resident species. For that reason, adding published list totals would risk double-counting fish or mixing different definitions of “found in Maine.”
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Scan for outdated or missing drivers - takes under a minuteDriver Scan →Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →| Question | Best-supported answer | Important limitation |
|---|---|---|
| How many freshwater-associated fish species does Maine have? | 71 species | The count includes fish that spend at least part of their life cycle in freshwater. |
| How many sea-run fish species does Maine have? | 12 species | These fish are a life-cycle group and overlap with freshwater and marine categories. |
| How many fish species occur in all Maine habitats? | No single reviewed official total | A complete answer would need to standardize freshwater, estuarine, coastal, offshore, seasonal, and transient records. |
| Can the freshwater and marine figures simply be added? | No | Migratory species can occur in both lists, creating potential double-counting. |
Why do freshwater and marine fish counts overlap?
Freshwater and marine counts overlap because some Maine fish are diadromous: they move between freshwater and saltwater during their lives. Maine DMR defines sea-run, or diadromous, fishes as fish that “spend one part of their lives in freshwater and another part in saltwater.”
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Maine DMR identifies 12 sea-run fish species. Eleven are anadromous: they are born in freshwater, mature in the ocean, and return to Maine freshwater to reproduce. The American eel is catadromous: it is born in the ocean and migrates into freshwater to grow and mature. These life cycles make a single habitat-based total difficult to interpret.
| Migration type | Where the fish begins life | Where the fish grows or matures | Typical movement |
|---|---|---|---|
| Anadromous | Freshwater | Saltwater | Returns to freshwater to reproduce |
| Catadromous | Saltwater | Freshwater | Moves to the ocean to reproduce |
| Diadromous | Freshwater or saltwater, depending on the species | Both environments during the life cycle | General term for regular movement between freshwater and saltwater |
Examples of fish that illustrate the overlap include American eel, Atlantic salmon, alewife, blueback herring, rainbow smelt, sea lamprey, sturgeons, striped bass, tomcod, and sea-run brook trout. A fish can therefore be relevant to an inland-fisheries list and a marine or sea-run resource without representing two different species.
How many of Maine’s fish are native?
Approximately 49 of the 71 freshwater-associated species—about 70%—are identified as native to Maine in the Maine Natural Areas Program report. The report also cautions that “native to Maine” does not mean that a species historically occurred throughout its present distribution in every part of the state.
Introductions and human-assisted translocations have shaped Maine’s present freshwater fish community. The terms describe different situations:
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- Native to Maine: The species was historically part of Maine’s fauna, without necessarily occupying every watershed or region.
- Introduced: People brought the species to Maine from somewhere outside its historical Maine range. Introduced fish can come from elsewhere in North America or from Eurasia.
- Translocated: The species is native to one part of Maine but was moved by people into waters where it was not originally present.
Native, introduced, and translocated are origin categories, not simple measures of whether a fish is beneficial, harmful, common, or desirable to anglers. A species’ conservation status and management rules require separate evaluation.
What kinds of fish are found in Maine?
“Types” can mean species, taxonomic groups, habitats, migration patterns, or fishing categories. For a practical overview, Maine fish can be organized in several ways:
- By habitat: freshwater, estuary, coastal marine, or offshore marine.
- By life cycle: resident freshwater, anadromous, catadromous, or another form of diadromous movement.
- By origin: native, introduced, or translocated.
- By human use or management: coldwater game fish, warmwater game fish, forage fish, commercial species, or species of conservation concern.
The Maine Department of Inland Fisheries & Wildlife organizes its fisheries information around categories including coldwater game fish, warmwater game fish, and miscellaneous species. Its official species-information page covers fish such as brook trout, brown trout, lake trout, landlocked salmon, splake, rainbow trout, Arctic charr, cusk, rainbow smelt, lake whitefish, round whitefish, bass, pickerel, pike, perch, bullhead, sunfish, alewife, and American eel.
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Where can you identify Maine fish?
For inland fish, start with the Maine Department of Inland Fisheries & Wildlife’s Fishes of Maine PDF. The state’s Maine Fishing Guide adds an illustrated fish-identification chart, species-specific fishing information, regional fisheries listings, and guidance about keeping or releasing fish.
For marine species, use the Maine Department of Marine Resources’ species-information directory. DMR also directs readers toward NOAA Fisheries, FishWatch, the Atlantic States Marine Fisheries Commission, and regional identification references. For a deeper marine reference, see Fishes of the Gulf of Maine, the regional book recommended by Maine DMR. The book is optional supplemental reading; verify the current edition and availability before purchasing.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why is there no single exact count for every fish in Maine?
No current official source reviewed for this question supplies a single taxonomically standardized total covering every fish species that may occur in Maine’s freshwater, estuarine, coastal, offshore, seasonal, and transient environments. A statewide total would need to define whether it includes occasional visitors, offshore records, stocked fish, translocated populations, and species recorded only in particular seasons.
A separate 2025 U.S. Geological Survey data release reports 53 fish species in a combined freshwater occurrence-data release covering Maine and five other northeastern states. That figure is regional and must not be used as Maine’s total.
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Maine has 71 fish species that spend at least part of their life cycle in freshwater, according to the Maine Natural Areas Program. Those fish represent 45 genera and 18 families. Maine also has marine and sea-run fish, including 12 species identified by Maine DMR as diadromous. Because migratory fish overlap freshwater and saltwater resources, no single reviewed official source establishes one complete count for every fish species found throughout Maine.
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Frequently Asked Questions
How many types of fish are in Maine?
The clearest official count is 71 fish species that spend at least part of their life cycle in Maine’s freshwater. The number does not include a complete, unified count of every marine, estuarine, coastal, and offshore species.
How many sea-run fish species are in Maine?
Maine’s Department of Marine Resources identifies 12 sea-run, or diadromous, fish species. Eleven are anadromous and return to freshwater to reproduce; the American eel is catadromous and moves into freshwater to grow and mature.
How many of Maine’s fish species are native?
Approximately 49 of Maine’s 71 freshwater-associated fish species, or about 70%, are identified as native. Native status does not mean that a species historically occurred throughout every part of Maine.
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The best-supported answer is 71 freshwater-associated fish species. That number is not a complete count of all fish in Maine’s marine, estuarine, coastal, and offshore waters. Maine DMR separately identifies 12 sea-run species, several of which overlap freshwater and marine categories.
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