The class this reference has had a name for since v8, and no animal in it until now.
First checkCount the long arms. Eight arms plus two much longer tentacles is a squid; eight and nothing longer is an octopus.
A squid is eight arms, two much longer tentacles with spoon-shaped sucker-covered ends, a torpedo-shaped mantle, and a pair of fins that in the Atlantic longfin run at least half the length of that mantle. It moves by pumping water in through the open mantle and forcing it out through a funnel, so it goes backwards on purpose, and it changes colour and pattern while you watch by expanding and contracting pigment cells in the skin. NOAA also says the longfin is probably colour blind, which is a fact worth sitting with.NOAA-SQUIDOLOGY, NOAA-LONGFIN-SQUIDEvidence from: General squid character (both species)Dispute
For an angler the useful behaviour is vertical. Atlantic longfin adults are on the bottom by day and disperse up into the water column at night; young longfin live in the upper ten metres over water roughly fifty to a hundred and fifty metres deep. North of Cape Hatteras the longfin come inshore in spring and stay until late autumn, then move out to the shelf edge for winter — and off Massachusetts the big ones arrive first, in April and May, with the smaller ones following in summer. The Pacific market squid keeps a different calendar: it lives offshore and comes into shallow sandy water to spawn, usually April to October in central California and October to April or May in southern California.NOAA-LONGFIN-SQUID, NOAA-EFH-LONGFIN-SQUID, MADMF-LONGFIN-SQUID, NOAA-MARKET-SQUID, CDFW-MARKET-SQUID-FMPEvidence from: Atlantic longfin and Pacific market squid, stated separatelyDispute
Now the honest part, and it is a big one. Nothing in the consulted sources describes what a squid looks like from the surface, in the surf, or in an estuary. NOAA states plainly that the Pacific market squid is rarely found in estuaries, bays or river mouths; Atlantic longfin, by contrast, turn up in Narragansett Bay, Long Island Sound and the Hudson-Raritan estuary. If you are watching bait flush in a bay and wondering whether it was squid, this record cannot help you, and it is not going to pretend it can.NOAA-MARKET-SQUID, NOAA-EFH-LONGFIN-SQUIDEvidence from: Estuary use differs by oceanDispute
The tell
What settles it, and what settles against it.
Read off this record's own diagnostic weights, heaviest first. A structure near the top of the left column does most of the work on its own; one near the bottom only leans.
Argues for Inshore squid
Eight arms plus two longer tentacles+8
Fins along a torpedo-shaped mantle+7
Shoots backwards in a jet, and changes colour+6
Moving as a school or tight bait cluster, not as a single insect+3
Argues against it
Fish-shaped forage silhouette (minnow / shiner / fry) — not an insect-4
A structure at −4 or below is treated as a hard exclusion by the comparison tool rather than as a penalty: if you saw it, this group is ruled out and no amount of matching elsewhere brings it back. Run a comparison →
Life stages
What it looks like, stage by stage.
no reviewed plateNothing consulted describes a paralarva beyond its mantle length, so there is nothing reviewed to draw.Inshore squid — Paralarvagap
Paralarva
Size in hand1.4–15 mm mantle length (Atlantic longfin)NOAA-EFH-LONGFIN-SQUIDEvidence from: Atlantic longfin squid (Doryteuthis pealeii), northwest Atlantic shelfDispute
What you see
Mantle length is the only sourced character at this stageDispute
In surface water by day and night, moving deeper as it grows (Atlantic longfin).NOAA-EFH-LONGFIN-SQUIDEvidence from: Atlantic longfin squid (Doryteuthis pealeii), northwest Atlantic shelfDispute
Inshore squid — Juveniledrawn
Juvenilethe stage a fish meets
Size in hand15–80 mm mantle length (Atlantic longfin)NOAA-EFH-LONGFIN-SQUIDEvidence from: Atlantic longfin squid (Doryteuthis pealeii), northwest Atlantic shelfDispute
What you see
In the Atlantic longfin, at about 45 mm the pigment cells shift to the upper surface, marking the move from surface water to a life near the bottomNOAA-EFH-LONGFIN-SQUID, MADMF-LONGFIN-SQUIDEvidence from: Atlantic longfin squid (Doryteuthis pealeii), northwest Atlantic shelfDispute
Where it turns up
Atlantic longfin: in the upper ten metres over water roughly fifty to a hundred and fifty metres deep. Young Pacific market squid stay just off the bottom on the shelf by day and spread through the water column at night.NOAA-EFH-LONGFIN-SQUID, CDFW-MARKET-SQUID-FMPEvidence from: Atlantic longfin and Pacific market squid, stated separatelyDispute
On the Atlantic longfin, fins running at least half the length of the mantleNOAA-LONGFIN-SQUID, MADMF-LONGFIN-SQUIDEvidence from: Atlantic longfin squid (Doryteuthis pealeii), northwest Atlantic shelfDispute
Eight arms plus two much longer tentacles with spoon-shaped, sucker-covered endsNOAA-SQUIDOLOGY, CDFW-MARKET-SQUID-FMPEvidence from: General squid character (both species)Dispute
Large eyes; on the Atlantic longfin each is covered by a corneaNOAA-LONGFIN-SQUID, CDFW-MARKET-SQUID-FMPEvidence from: Atlantic longfin squid (Doryteuthis pealeii), northwest Atlantic shelfDispute
Atlantic longfin: pink or orange, mottled with brown or purple. Pacific market squid: iridescent milky white and purple. Both change colour as you watch.NOAA-LONGFIN-SQUID, NOAA-MARKET-SQUID, CDFW-MARKET-SQUID-FMPEvidence from: Atlantic longfin and Pacific market squid, stated separatelyDispute
Atlantic longfin: on the bottom by day, up into the water column at night; north of Cape Hatteras, inshore spring through autumn and offshore along the shelf edge in winter. Pacific market squid: offshore, coming into shallow sandy water to spawn — summer in central California, winter in southern California.NOAA-LONGFIN-SQUID, NOAA-EFH-LONGFIN-SQUID, NOAA-MARKET-SQUID, CDFW-MARKET-SQUID-FMPEvidence from: Atlantic longfin and Pacific market squid, stated separatelyDispute
Where in the column it mattersMid column. The band is set by the clock rather than the season, on both coasts: deeper or on the bottom by day, up in the column at night.
Read from the record's own position notes: Atlantic longfin squid: on the bottom by day, dispersing up into the water column at night; young Atlantic longfin squid live in the upper ten metres over water roughly fifty to a hundred and fifty metres deep; Pacific market squid: young squid stay just off the bottom on the shelf by day and spread through the water column at night; adults also sit deeper by day than at night.
Reference windows
When this group is typically available.
Typical published ranges only. Elevation, latitude, tailwater release and a given year's weather move all of these, often by weeks. This is never a statement about today.
2 reference windows
Inshore seasonadult
JFMAMJJASOND
Longfin squid are generally found in water of at least about 48 °F (9 °C). Off Massachusetts the larger animals come inshore first, in April and May, and smaller ones follow through the summer.
Observed: Atlantic longfin squid; dated from Massachusetts waters. Not the Pacific market squid, which comes inshore to spawn in winter in southern California.
Sub-adults are out on the outer shelf from about November until March. Spawning cohorts occur throughout the year, so the seasonal signal here is the movement, not the spawn.
Observed: Atlantic longfin squid; dated from Massachusetts waters and the northeast shelf. Not the Pacific market squid.
No reviewed dossier names this group. That is an absence in the dossier layer rather than a finding about the animal — four dossiers exist and only one of them names any forage group at all.
The pattern layer ties this group in Streamer. That is a correspondence between an imitation and an animal, worked out when the patterns were written. Whether a fish is on it today is a question this page cannot reach.
Squid Fly
Streamer
Hook2/0–2
An inshore squid — eight arms, two tentacles, a mantle that changes colour.
Erratic strips with pauses. Jetting backwards is the living animal.
11 of them. The limits are part of what was reviewed rather than a disclaimer bolted on afterwards. An entry that hid them would be claiming more than it checked.
Written by the reviewer
Declared by the reviewerNo consulted source states an arm and tentacle count for the longfin squid specifically; the eight-plus-two count is sourced as a general squid character and for the Pacific market squid.NOAA-SQUIDOLOGY, NOAA-MARKET-SQUID, CDFW-MARKET-SQUID-FMPEvidence from: General squid character (both species)Dispute
Declared by the reviewerNo consulted source gives a character that tells Atlantic longfin from Pacific market squid in the hand; they describe different colours and sizes, but the ocean is the working separator.NOAA-LONGFIN-SQUID, NOAA-MARKET-SQUIDEvidence from: Both species comparedDispute
Declared by the reviewerNothing consulted describes squid from the surface, in the surf, or in an estuary.Dispute
Declared by the reviewerNo source consulted states an arm and tentacle count for the longfin squid specifically. The eight-plus-two count is sourced as a general squid character and for the Pacific market squid.NOAA-SQUIDOLOGY, NOAA-MARKET-SQUID, CDFW-MARKET-SQUID-FMPEvidence from: General squid character (both species)Dispute
Declared by the reviewerNo source consulted offers a character that tells Atlantic longfin from Pacific market squid in the hand. The sources describe different colours (pink or orange and mottled on the longfin, milky white and purple on the market squid) and different maximum sizes, but none offers them as a separator; the ocean does that work.NOAA-LONGFIN-SQUID, NOAA-MARKET-SQUIDEvidence from: Both species comparedDispute
Declared by the reviewerNothing in the consulted sources describes what a squid looks like from the surface, in the surf or in an estuary. Atlantic longfin squid have been caught in Narragansett Bay, Long Island Sound and the Hudson-Raritan estuary; NOAA states plainly that Pacific market squid are rarely found in estuaries, bays or river mouths. If you are watching bait flush in a bay, this record cannot tell you it was squid.NOAA-EFH-LONGFIN-SQUID, NOAA-MARKET-SQUIDEvidence from: Estuary use differs by oceanDispute
Declared by the reviewerMaximum mantle length for the Atlantic longfin is published as over 40 to 50 cm, as about 50 cm, as 47 cm, and as 1.6 feet. Roughly consistent, but no one figure is offered as definitive.MADMF-LONGFIN-SQUID, NOAA-EFH-LONGFIN-SQUID, VIMS-LONGFIN-SQUID, NOAA-LONGFIN-SQUIDEvidence from: Atlantic longfin squid (Doryteuthis pealeii), northwest Atlantic shelfDispute
Sources disagreeSpawning windows for the Pacific market squid differ between two sources that also name different regions: April to October in central California in NOAA's account, April to November in northern California in California Sea Grant's.
Sources disagreeJuvenile longfin depth differs within and between NOAA sources: the essential-habitat document gives the upper 10 m over water 50-150 m deep in its text and 50-100 m in its table, and NOAA's species page gives water 165 to 1,650 feet deep.
Sources disagreeThe longfin's lower temperature limit is given as at least 9 °C (48 °F) by Massachusetts DMF and as a minimum of 8 °C (46 °F) by the FAO account VIMS reproduces.
Read off the record
Nobody typed these. They are fields that are empty, said out loud rather than left for you to notice from a section that simply is not there.
What eats itNo reviewed species dossier names this group. Some dossiers describe forage in class terms — small forage, insects, bait — and those are shown below, but a class description is not a reviewed link to this group and none is claimed.
Sources
Everything above rests on 8 published pages.
These are every page behind this entry. Where a reviewer traced a line above to the pages that carry it, that line names them itself, with where the evidence comes from when it is narrower than the whole entry. A line with no names beside it rests on this list as a whole: nobody has yet checked which page carried it, and naming one would be a mapping nobody made.
A plate shows shape. It cannot show a gill beating, a mask firing, or an animal reversing into sand — so where motion is the field mark, the entry points at motion. These are demonstrations, selected by hand and by publisher. Nothing here is a source: it changes no score, no window and no reviewed claim.
LUMCON. The same structure at marine-lab magnification, on a specimen in hand.
Research institute · external video · title read back from the publisher 2026-09-09
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