Sea surface temperature guide
Longbill Spearfish sea surface temperature guide.
- Tetrapturus pfluegeri
- Billfish
- Estimated threshold data
Longbill spearfish are the rarest of the billfish encountered in US offshore waters — opportunistic bycatch on canyon trolls. Document for completeness; the targeting is incidental.
SST threshold gauge
The temperature ranges that matter.
The water temperature ranges that determine where longbill spearfish hold and feed. Hard thresholds (dashed lines) are values outside which fish actively depart or become inactive.
Depth profile & SST reliability
Typical depth
0–600 feet
SST as locator
Moderate — SST is a partial signal
Surface and mid-water feeder. SST broadly predictive but these fish are uncommon enough that any encounter is opportunistic.
Current systems & structure
Spearfish are a deep blue-water species, more common offshore of the Mid-Atlantic and Gulf canyon edges than near shore.
Best zones now
Where longbill spearfish are in range — August.
Zones where typical August SST falls in longbill spearfish's preferred range.
Zone-by-zone calendar
Overlap charts by zone.
For each zone where longbill spearfish are present, the chart overlays the zone's typical monthly SST range with the species' preferred and optimal ranges. Months where the bands overlap are when fish are in range.
Northeast
Best months
July, August
| Month | Zone SST | Status |
|---|---|---|
| Jan | 42–48°F | Outside |
| Feb | 42–48°F | Outside |
| Mar | 44–50°F | Outside |
| Apr | 46–54°F | Outside |
| May | 52–60°F | Outside |
| Jun | 60–68°F | Outside |
| Jul | 65–75°F | Peak |
| Augnow | 68–78°F | Peak |
| Sep | 64–72°F | Fishable |
| Oct | 56–64°F | Outside |
| Nov | 50–58°F | Outside |
| Dec | 44–52°F | Outside |
Mid-Atlantic
Best months
July, August, September
| Month | Zone SST | Status |
|---|---|---|
| Jan | 44–52°F | Outside |
| Feb | 44–50°F | Outside |
| Mar | 44–52°F | Outside |
| Apr | 46–56°F | Outside |
| May | 54–64°F | Outside |
| Jun | 62–72°F | Fishable |
| Jul | 68–78°F | Peak |
| Augnow | 70–80°F | Peak |
| Sep | 66–74°F | Peak |
| Oct | 58–66°F | Outside |
| Nov | 52–60°F | Outside |
| Dec | 46–54°F | Outside |
Best months
June, July, August, September
| Month | Zone SST | Status |
|---|---|---|
| Jan | 46–54°F | Outside |
| Feb | 46–54°F | Outside |
| Mar | 48–56°F | Outside |
| Apr | 50–60°F | Outside |
| May | 56–66°F | Outside |
| Jun | 64–74°F | Peak |
| Jul | 70–80°F | Peak |
| Augnow | 72–82°F | Peak |
| Sep | 68–76°F | Peak |
| Oct | 60–68°F | Outside |
| Nov | 54–62°F | Outside |
| Dec | 48–56°F | Outside |
Best months
June, July, August, September
| Month | Zone SST | Status |
|---|---|---|
| Jan | 48–58°F | Outside |
| Feb | 48–56°F | Outside |
| Mar | 50–60°F | Outside |
| Apr | 54–64°F | Outside |
| May | 60–70°F | Fishable |
| Jun | 68–78°F | Peak |
| Jul | 72–82°F | Peak |
| Augnow | 74–84°F | Peak |
| Sep | 70–80°F | Peak |
| Oct | 64–72°F | Fishable |
| Nov | 56–64°F | Outside |
| Dec | 50–60°F | Outside |
Conservation & regulations
ICCAT / NOAA HMS
Insufficient data — managed under ICCAT billfish framework. Catch and release standard. HMS permit required for billfish targeting.
Stock assessment source →Spearfish are bycatch on white marlin and tuna trolls in canyon waters. They eat the same baits as whites but ride deeper. Most encounters are accidental.
Sources
SST threshold data is summarized from agency and research sources. Year-to-year ocean conditions vary; verify current SST imagery before each trip.
See live SST for your offshore zone.
Bield: Fish overlays NOAA CoastWatch SST imagery on your chartplotter view, highlights the temperature breaks that match longbill spearfish thresholds, and alerts you when your home zone hits the 72–77°F window.
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