Reef & bottom · Saltwater
Pacific halibut
Hippoglossus stenolepis
North Pacific and Bering Sea marine native; U.S. range from Santa Barbara, California to Nome, Alaska, and across to Russia and Japan.
Also called halibut.
- Nearshore
- Offshore
- Regulated context
- 4 of 4 overlays reviewed
- Reviewed 2026-08-27
Before you target this fish
Regulated context — check the rules for the exact water
Where this applies International Pacific Halibut Commission (IPHC) regulatory areas spanning Alaska, British Columbia, and the U.S. West Coast (Convention between the U.S. and Canada); within the U.S., NOAA Fisheries, the North Pacific Fishery Management Council, the Pacific Fishery Management Council, and state agencies (ADF&G, CDFW) implement IPHC measures for their waters.
The reviewed context, unedited
Pacific halibut is managed under a bilateral U.S.-Canada convention administered by the IPHC, which divides the range into numbered regulatory areas (e.g., 2A off Washington/Oregon/California, 2C and 3A-3B in Alaska, 4A-4E further west) and sets an annual catch limit and recreational/charter rules per area through Annual Management Measures published each year -- describe the structure, not a specific year's dates. The structure itself varies sharply by area: Alaska's Area 2C charter fishery has used a reverse-slot size limit (keep only fish at or under a set length, or over a much larger second threshold) with a one-fish bag; Area 3A has used a tiered two-fish bag (one fish of any size plus one fish under a set smaller length); California's Area 2A recreational fishery instead uses a one-fish bag with no minimum size and gear restrictions (no more than one line with two hooks). Exact size thresholds, bag numbers, and open days are reset annually by IPHC/NPFMC/PFMC/NOAA Fisheries and must be checked for the current year and specific area before fishing.
Rules for this fish change at a state line and sometimes inside one. Check the ones that apply to the exact water you are standing on before you act on anything here — this record is biology, not permission.
Take this somewhere
This page is the record. The reading is what happens when you add water, a season and a temperature to it — that is where the families below get ranked against each other instead of just listed.
Those three links carry the fish and nothing else. No conditions were declared on this page, so none travel, and the link says so rather than sending an empty reading.
The half nobody publishes
What this record does not know
Everything else on this page comes from a named agency or peer-reviewed source. This is the other side of that: the questions a reviewer went looking for an answer to and came back without, and the fields the record leaves empty because filling them would mean guessing.
It is here rather than at the bottom because a page that only shows what it knows is easy to read as a page that knows everything. For Pacific halibut there are 13 of them.
Named by a reviewer
10Somebody looked for this and wrote down that they did not find it.
- Behaviour
No sourced diel activity pattern; "mixed" above is a placeholder, not a documented finding.
The specific temperature-vs-activity relationship from laboratory research (Seitz et al.) could not be retrieved from an accessible source during this research pass.
No sourced current-facing or tide-specific behavior.
No sourced predator-avoidance or angling-pressure response.
- Identification
No sourced average adult length or typical angling weight distinct from the documented maximum.
No sourced side-by-side identification comparison against other North Pacific flatfish (e.g., arrowtooth flounder); only halibut's own diagnostic traits were found.
- Forage
No sourced seasonal diet breakdown.
No sourced preferred prey size relative to halibut body size.
- Season
Month-specific migration timing not found beyond the general winter-spawning/summer-feeding pattern.
No sourced current/tide interaction with the seasonal migration.
Absent from the record
3No reviewer wrote a gap here. The field is simply empty, which is its own answer.
- Water temperature
No agency or peer-reviewed temperature band for Pacific halibut was found that a review would accept. The reading runs without one rather than borrowing a number from a related fish.
- Identification
No reviewed image. A photograph is only in this catalog when an agency or a named creator labelled the subject, and nobody has cleared one for this species yet.
- Population context
No regional population profile is registered. The species-level reading stands on its own; it does not silently become a local one.
Where the record puts it
Water and range
Nearshore
1 reviewed holding class- Nearshore hump
Offshore
2 reviewed holding classes- Offshore ledge
- Canyon edge
DepthTypically found 20-1,000 ft deep, with records to about 3,600 ft. Adults migrate seasonally: deeper (continental slope, roughly 600-1,600+ ft) in winter for spawning, shallower shelf/bank feeding grounds the rest of the year. Juveniles migrate further offshore with age, reaching coastwide distribution by about age five or six.
Moving waterNot documented against tide directly in sourced material. Halibut are noted to leave the bottom opportunistically to intercept pelagic prey such as sand lance and herring, rather than holding purely on a current seam.
LightNot documented in sourced material.
Thermal band
Temperature
No reviewed temperature band
Nobody publishes a preferred or active temperature range for Pacific halibut that a review would accept. Borrowing one from a related fish would look like knowledge and behave like a guess, so the reading runs without it and says which parts of the answer that weakens.
How it uses water
Behaviour
No sourced schooling behavior; halibut are typically encountered as individual bottom-oriented fish, though they aggregate seasonally on spawning grounds (conservation context, not a targeting note) and to some degree on productive feeding banks.
Primarily a benthic ambush predator on other groundfish, flatfish, and invertebrates, but will actively leave the bottom to pursue pelagic prey such as herring and sand lance (ADF&G; NOAA Fisheries).
No species-specific diel activity data (day vs. night feeding timing) were found in sourced material. "Mixed" is recorded here as an honest placeholder, not a sourced finding -- see gaps.
Temperature-driven behaviourADF&G and IPHC materials describe halibut as preferring water temperatures of about 37-46 degF (3-8 degC) -- stated in sourced material as a preference, not merely a distribution record. A separate laboratory study (Seitz et al., referenced in search results) reports that temperature affects Pacific halibut activity and feeding motivation, but the specific experimental values could not be retrieved from an accessible source during this research pass.
Depth movementAdults migrate seasonally: deeper (continental slope, roughly 600-1,600+ ft) in winter for spawning, and shallower summer feeding grounds the rest of the year. Juveniles migrate progressively further offshore with age, reaching coastwide distribution by about age five or six.
CoverRelies on cryptic mottled coloration against sand/mud bottom rather than hard structure; not documented as a structure-oriented species in sourced material.
Spawning (conservation context)Spawns in deep water along the continental slope, roughly November through March, at depths of about 600-1,600+ ft. Females release 500,000 to 4 million eggs per season, in batches over several days; eggs hatch in 12-20 days depending on temperature. No spawning site or aggregation location is named.
What it can eat
Forage
- Small forage fish
- Larger prey fish
- Mollusks
- Crustaceans
Diet shifts strongly with life stage: larvae take zooplankton; juveniles (about ages 1-3) take small crustaceans and small fish; adults are generalist groundfish predators taking cod, sablefish, pollock, rockfish, other flatfish, and occasionally smaller halibut, plus octopus, crabs, and clams, and will leave the bottom to take pelagic sand lance and herring. Diet capacity is not evidence of a current bait event.
- Feeding style
- Opportunistic
- Feeding zone
- Mixed
By life stage
- Young of year
- Larvae consume zooplankton.
- Juvenile
- Small crustaceans and small fish (roughly ages 1-3).
- Adult
- Groundfish (cod, sablefish, pollock, rockfish, other flatfish, occasionally smaller halibut), octopus, crabs, and clams; also pelagic sand lance and herring taken off-bottom.
Ontogenetic shiftZooplanktivorous larvae, to small-crustacean/small-fish juveniles, to large piscivorous/invertebrate-eating adults.
Diet capacity is not proof that a hatch or prey event is occurring. Observed current forage still comes from a user observation or Hatch Match.
Through the year
Season
Winter
- Where they sit
- Deep continental slope, roughly 600-1,600+ ft.
- Depth
- Deepest seasonal position of the year.
What that changesDeep-drop presentations are the reviewed match for this depth band, where any fishery remains open at all -- most sport fisheries are closed in this depth range and season.
What would count against it
- treating winter deep-water aggregation as a location to target -- spawning concentrations are conservation context only
Primary spawning season, roughly November through March; no spawning site is named.
Spring
- Where they sit
- Transitional: migrating from deep winter spawning grounds back toward shallower shelf feeding grounds.
- Movement
- Return migration toward summer feeding areas.
What would count against it
- assuming a fixed calendar date for the transition; timing is not finely dated in sourced material
Summer
- Where they sit
- Shallower shelf/bank feeding grounds, roughly 20-1,000 ft typical depth.
- Depth
- Shallowest seasonal position; most sport and commercial harvest activity occurs now.
- Feeding
- Groundfish and invertebrate prey taken on or near the bottom, plus pelagic sand lance and herring taken off-bottom.
What that changesBottom-contact and drop presentations match the benthic ambush mode in nearshore/bank water; deep-drop for deeper offshore structure.
Spawning · Late fall, Winter
Spawns in deep water along the continental slope, roughly November through March, at depths of about 600-1,600+ ft (200->500 m). This is conservation context only, not a location.
Recorded as conservation context. No spawning site, staging concentration or migration bottleneck is named anywhere in this catalog, because naming one is how a population gets fished out.
Telling it apart
Identification
What to look at
- Nearly always right-eyed, with both eyes on the upper, dark side of the body; left-eyed individuals are exceptionally rare (ADF&G).
- Lateral line strongly arched above the pectoral fin (ADF&G).
- Tail broad, symmetrical, and lacking a distinct fork -- unlike many other North Pacific flatfish (ADF&G).
- Small, embedded scales give the body a smooth appearance (NOAA Fisheries).
- Average adult length
- Not found as a distinct 'average' figure in sourced material; maximum documented length is about 8-9 ft (2.4-2.7 m).
- Common angling size
- Not found in sourced material.
- Typical weight
- Not found in sourced material beyond the maximum weight and the note that males remain smaller than females.
- Maximum documented
- Documented to about 8-9 ft (2.4-2.7 m) and over 500 lb (230 kg); ADF&G, IPHC, and NOAA Fisheries figures agree closely on these maxima.
- Longevity
- Up to 55 years for both sexes -- the oldest documented age (ADF&G; IPHC).
What it gets confused with
- Other large North Pacific flatfish encountered incidentally (e.g., arrowtooth flounder)
- Sourced material did not provide a direct side-by-side comparative identification key against other flatfish. The features agencies use to identify halibut itself -- a strongly arched lateral line over the pectoral fin and a broad, symmetrical, unforked tail -- are recorded above as the practical distinguishing traits.
What follows from all of that
Presentation families
Nearshore
Bottom contact
Keep a bait on or just above the substrate along a break, flat, or inside a weed edge.
- feel bottom
- drag or hop
- pause on the break
- stay in contact
What it asks of the tackle
- Depth control
- High
- Sensitivity
- High
- Casting distance
- Moderate
- Weight range
- 1/8–1/2 oz
- Cover resistance
- High
- Line visibility
- Low
- Retie frequency
- High
Drop presentation
Let a bait fall on a controlled line into cover, along a wall, or through a hole in vegetation.
- place then fall
- watch the line
- hold at depth
- short hop only after the fall
What it asks of the tackle
- Depth control
- High
- Sensitivity
- High
- Casting distance
- Short
- Weight range
- 1/16–3/8 oz
- Cover resistance
- High
- Line visibility
- Low
- Retie frequency
- High
Vertical jig
Work a compact bait up and down through a marked depth, basin, or timber pocket.
- stay over the target
- measured lift
- controlled drop
- watch slack
What it asks of the tackle
- Depth control
- High
- Sensitivity
- High
- Casting distance
- Vertical
- Weight range
- 1/8–3/4 oz
- Cover resistance
- Moderate
- Line visibility
- Low
- Retie frequency
- Moderate
Offshore
Deep drop
Put bait on the bottom in water deep enough that the drop itself is most of the work.
- heavy enough to go straight down
- know when you are down
- short lift to check
- wind steadily
What it asks of the tackle
- Depth control
- High
- Sensitivity
- Low
- Casting distance
- None
- Weight range
- 8–48 oz
- Cover resistance
- Moderate
- Line visibility
- Secondary
- Retie frequency
- Moderate
Vertical jig
Work a compact bait up and down through a marked depth, basin, or timber pocket.
- stay over the target
- measured lift
- controlled drop
- watch slack
What it asks of the tackle
- Depth control
- High
- Sensitivity
- High
- Casting distance
- Vertical
- Weight range
- 1/8–3/4 oz
- Cover resistance
- Moderate
- Line visibility
- Low
- Retie frequency
- Moderate
What moves them for this fish
Reviewed rules that push particular families up when the conditions match. Each one names the conditions it needs and why it exists, so you can disagree with it.
When baitfish such as herring or sand lance are actually being observed, halibut are documented to actively leave the bottom to intercept them, so a presentation worked up through the column outranks one left flat on bottom.
When
Nearshore · Small forage fish
Moves up
Vertical jig
Reviewed 2026-08-30
The same off-bottom pursuit behavior applies offshore: verified baitfish forage favors a worked mid-column presentation over one parked on the bottom.
When
Offshore · Small forage fish
Moves up
Vertical jig, Deep drop
Reviewed 2026-08-30
Where every sentence came from
Sources
Agency
ADF&G Pacific Halibut species profile
Used for habitat, thermal band and presentation families; identification; behaviour; forage; season. Read 2026-08-30, next check 2026-11-27.
Agency
IPHC Pacific Halibut (Hippoglossus stenolepis): Stock Status and Biology
Used for habitat, thermal band and presentation families; identification; behaviour; season. Read 2026-08-30, next check 2026-11-27.
Agency
NOAA Fisheries Pacific Halibut species page
Used for identification; behaviour; forage. Read 2026-08-30, next check 2026-11-29.
Agency
NOAA Fisheries, "Halibut Sport Fishing in Alaska" / 2026 Charter Halibut regulation FAQ
Used for habitat, thermal band and presentation families; season. Read 2026-08-30, next check 2026-11-27.
Agency
IPHC Structure of the Commission
Used for habitat, thermal band and presentation families. Read 2026-08-27, next check 2026-11-27.
Agency
CDFW Pacific Halibut conservation/regulations page
Used for habitat, thermal band and presentation families. Read 2026-08-27, next check 2026-11-27.
A source with no link predates the rule that one has to carry a URL. It is still a real citation and still checkable; it just takes a search rather than a click, and that is worth knowing before you rely on it.