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Sea Lamprey

Petromyzon marinus

Fish · family Petromyzontidae · order Petromyzontiformes

  1. G1
    Critically imperiled
  2. G2
    Imperiled
  3. G3
    Vulnerable
  4. G4
    Apparently secure
  5. G5
    Secure

NatureServe global rank G5: secure[2].

Updated October 30, 2026. Published by Humblebee.

Endangered Species Act
Not listed[1]
NatureServe global rank
G5 Secure[2]
Native in
16 states[3]
Longest recorded life
9 years[4]

The Sea Lamprey (Petromyzon marinus) is a fish in the family Petromyzontidae[5]. NatureServe ranks it Secure worldwide and in the United States, and it is not listed under the US Endangered Species Act[2][6][1].

Conservation status

NatureServe gives the Sea Lamprey a global rank of G5, which means Secure[2]. Its national rank in the United States is N5, also Secure[6]. The IUCN Red List category recorded by NatureServe is Least concern[7]. The species is not listed as endangered or threatened under the US Endangered Species Act in USFWS data checked on 2026-10-30[1]. NatureServe says the population trend over recent years is uncertain, but likely fairly stable or slowly declining[8].

Status Value
Endangered Species Act[1] Not listed
NatureServe global rank[2] G5 (Secure)
NatureServe US rank[6] N5 (Secure)
IUCN Red List (via NatureServe)[7] Least concern

Where Sea Lamprey lives

NatureServe lists the Sea Lamprey as native in 16 US states and territories[3]. These are Connecticut, the District of Columbia, Delaware, Georgia, Massachusetts, Maryland, Maine, North Carolina, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, South Carolina, Virginia and Vermont[3]. It is listed as introduced, which means not native, in Illinois, Indiana, Michigan, Minnesota and Wisconsin[9]. A state list shows where NatureServe records the species, so it is not a promise that you will see one there[3].

Alaska: not recordedAKMaine: native, state rank S5MEWisconsin: introduced, state rank SNAWIVermont: native, state rank S4VTNew Hampshire: native, state rank S3NHWashington: not recordedWAIdaho: not recordedIDMontana: not recordedMTNorth Dakota: not recordedNDMinnesota: introduced, state rank SNAMNIllinois: introduced, state rank SNAILMichigan: introduced, state rank SNAMINew York: native, state rank S4NYMassachusetts: native, state rank S4MAOregon: not recordedORNevada: not recordedNVWyoming: not recordedWYSouth Dakota: not recordedSDIowa: not recordedIAIndiana: introduced, state rank SNAINOhio: not recordedOHPennsylvania: native, state rank S4PANew Jersey: native, state rank S5NJConnecticut: native, state rank S5CTRhode Island: native, state rank S3RICalifornia: not recordedCAUtah: not recordedUTColorado: not recordedCONebraska: not recordedNEMissouri: not recordedMOKentucky: not recordedKYWest Virginia: not recordedWVVirginia: native, state rank S4VAMaryland: native, state rank S4MDDelaware: native, state rank S4DEArizona: not recordedAZNew Mexico: not recordedNMKansas: not recordedKSArkansas: not recordedARTennessee: not recordedTNNorth Carolina: native, state rank S3NCSouth Carolina: native, state rank SUSCDistrict of Columbia: native, state rank S3BDCOklahoma: not recordedOKLouisiana: not recordedLAMississippi: not recordedMSAlabama: not recordedALGeorgia: native, state rank SUGAHawaii: not recordedHITexas: not recordedTXFlorida: not recordedFLPuerto Rico: not recordedPR
State presence as recorded by NatureServe[10].
Show state ranks (21 states)
StateRankMeaning
ConnecticutS5Secure
DelawareS4Apparently Secure
District of ColumbiaS3BVulnerable (breeding)
GeorgiaSUUnrankable
IllinoisSNANot Applicable
IndianaSNANot Applicable
MaineS5Secure
MarylandS4Apparently Secure
MassachusettsS4Apparently Secure
MichiganSNANot Applicable
MinnesotaSNANot Applicable
New HampshireS3Vulnerable
New JerseyS5Secure
New YorkS4Apparently Secure
North CarolinaS3Vulnerable
PennsylvaniaS4Apparently Secure
Rhode IslandS3Vulnerable
South CarolinaSUUnrankable
VermontS4Apparently Secure
VirginiaS4Apparently Secure
WisconsinSNANot Applicable

Habitat

NatureServe records many water types for this fish, including big rivers, medium rivers, creeks, riffles, pools, deep and shallow water, bays and river mouths[11]. Adults swim from the ocean or a lake up into streams to spawn[12]. Females lay many small eggs in nests that males build in gravel, sand and rubble where the current is moderately strong[12]. The young live buried in sand and silt in quiet water downstream of the nests[12].

Habitat types recorded by NatureServe[11]

Size, diet and lifespan

Adult Sea Lampreys live as parasites on fishes[13]. The young, called larvae, filter plankton and detritus from the water[13][12]. The typical length recorded by NatureServe is 120 cm (47 in)[14]. Eggs hatch in 10 to 12 days, and the larvae leave the nest after around three weeks[15]. The larval stage can last up to several years[15]. The longest recorded lifespan in the wild is 9 years, which is a record and not a typical lifespan[4].

Trait Value
Typical length[14] 120 cm (47 in)
Longest recorded lifespan (AnAge)[4] 9 years (wild)
Female maturity[16] 3,193 days (about 8.7 years)
Food habits[17] Piscivore, Herbivore
Migration[18] local migrant, long-distance migrant

When to look for it

Spawning happens in spring in most areas, or in summer[15]. Some populations travel up to about 50 miles upstream to spawn, and populations with ocean access travel up to 200 miles[19]. Observation records on GBIF peak in April, May and June[20]. These records show when people look and report, not how many animals there are[20].

January: 63 recordsJanFebruary: 152 recordsFebMarch: 290 recordsMarApril: 514 recordsAprMay: 528 recordsMayJune: 382 recordsJunJuly: 170 recordsJulAugust: 153 recordsAugSeptember: 130 recordsSepOctober: 104 recordsOctNovember: 65 recordsNovDecember: 378 recordsDec
US observation records on GBIF by month, all years. The three months with the most records are highlighted. Records show when people look and report, not how many animals there are[20].
Show records by month
MonthRecords
January63
February152
March290
April514
May528
June382
July170
August153
September130
October104
November65
December378

Where to see it

National Park Service species lists record Sea Lamprey as present in 12 park units[21]. Present means the park has a confirmed record, not that sightings are common.

States with the most GBIF observation records: New York, Michigan, Massachusetts, Maryland, North Carolina[22]. These counts follow where people look and report, not population size.

Questions people ask

Is the Sea Lamprey endangered?
No. It is not listed as endangered or threatened under the US Endangered Species Act[1]. NatureServe ranks it G5, which means Secure[2].
Where does the Sea Lamprey live in the US?
It is native in 16 US states and territories along the East Coast, from Maine to Georgia[3]. It is listed as introduced in Illinois, Indiana, Michigan, Minnesota and Wisconsin[9].
What does the Sea Lamprey eat?
Adults are parasitic on fishes, and the larvae filter-feed on plankton[13].
How big is a Sea Lamprey?
The typical length recorded by NatureServe is 120 cm (47 in)[14].
How long does a Sea Lamprey live?
The longest recorded lifespan in the wild is 9 years[4]. That is a record and not a typical lifespan.

Facts and sources

  1. Sea Lamprey is not listed as endangered or threatened under the US Endangered Species Act in USFWS ECOS data (checked 2026-10-30). USFWS ECOS
  2. NatureServe global conservation status rank for Sea Lamprey: G5 (Secure). NatureServe Explorer
  3. NatureServe lists Sea Lamprey as native in 16 US states and territories: Connecticut, the District of Columbia, Delaware, Georgia, Massachusetts, Maryland, Maine, North Carolina, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, South... NatureServe Explorer
  4. Maximum recorded lifespan in AnAge: 9 years in the wild. This is a record, not a typical lifespan. AnAge
  5. Sea Lamprey (Petromyzon marinus) is a fish in the family Petromyzontidae, order Petromyzontiformes. NatureServe Explorer
  6. NatureServe national rank in the United States: N5 (Secure). NatureServe Explorer
  7. IUCN Red List category as recorded by NatureServe: Least concern. NatureServe Explorer
  8. NatureServe notes on trend for Sea Lamprey. NatureServe Explorer
  9. NatureServe lists Sea Lamprey as introduced (not native) in: Illinois, Indiana, Michigan, Minnesota, Wisconsin. NatureServe Explorer
  10. NatureServe state ranks for Sea Lamprey (map and table on this page). NatureServe Explorer
  11. Habitat types NatureServe records for Sea Lamprey: Big river, Medium river, Creek, Moderate gradient, Low gradient, Riffle, Pool, Deep water, Shallow water, Bay/sound, River mouth/tidal river, Near shore. NatureServe Explorer
  12. NatureServe notes on habitat for Sea Lamprey. NatureServe Explorer
  13. NatureServe notes on food for Sea Lamprey. NatureServe Explorer
  14. Typical length recorded by NatureServe: 120 cm (47 in). NatureServe Explorer
  15. NatureServe notes on reproduction for Sea Lamprey. NatureServe Explorer
  16. Age at female sexual maturity in AnAge: 3,193 days (about 8.7 years). AnAge
  17. Adult food habits recorded by NatureServe: Piscivore, Herbivore. NatureServe Explorer
  18. NatureServe migration category for Sea Lamprey: local migrant, long-distance migrant (populations can differ). NatureServe Explorer
  19. NatureServe notes on migration for Sea Lamprey. NatureServe Explorer
  20. GBIF observation records of Sea Lamprey in the US by month (chart on this page). GBIF
  21. NPSpecies park lists recording Sea Lamprey as present (list on this page). NPS NPSpecies
  22. US states with the most GBIF observation records of Sea Lamprey: New York, Michigan, Massachusetts, Maryland, North Carolina. Record counts follow observer effort, not population size. GBIF

Status, range and habitat come from NatureServe Explorer (CC BY 4.0) and USFWS ECOS at the snapshot date. Listings change by federal rule. State lists are where NatureServe records the species, not a promise that you will see it there. Never name a place smaller than a state. GBIF and park records count observations and checklists. They show where and when people report the species, not how many animals live there.

NatureServe. 2026. NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org. (Accessed: October 30, 2026). Licensed under CC BY 4.0; SpeciesFacts selected and summarized it.