Operations at sea

Scientific mooring

Instruments anchored to the seabed and held up by floats, sometimes just below the surface, left for months to measure the ocean.

Oceanographers leave moorings in place for months or years: a line from an anchor on the seabed to floats that hold instruments at set depths. The warning gives the position and the depth of the top float — "TOP FLOAT AT 30 METERS" — and asks ships not to anchor, trawl or tow gear near it. Some moorings carry a surface buoy; many do not.

Because they stay for so long, scientific moorings are among the longest-running warnings in the Arctic and in polar research areas.

What the archive shows

511 messages in this archive use “Scientific mooring”, the earliest issued 1996-08-22 and the latest 2026-09-23. 3 of them are in force in the latest lists we collected. A hazard reported again and again counts once per message.

The largest yearly count is 2023, with 55 messages. Collection is incomplete between 2024-05 and 2026-08-17, so 2024, 2025 and 2026 are not comparable with fully collected years.

Surveys accounts for 491 of 511 recorded messages (96%), the largest warning type group in this selection.

Located messages that use it fall in 46 sea areas; the most frequent are Arctic Ocean (69), South Pacific Ocean (69) and Beaufort Sea (66).

Messages that use it are issued most often in October (108 across all years) and least often in March (9).

By warning series: HYDROARC 271, HYDROPAC 120, HYDROLANT 68 and NAVAREA IV 32, and 3 more.

Messages using it, by year of issue

'96
'97
'98
'99
'00
'01
'02
'03
'04
'05
'06
'07
'08
'09
'10
'11
'12
'13
'14
'15
'16
'17
'18
'19
'20
'21
'22
'23
'24
'25
'26

By month of issue, all years

Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec

Where it appears · 46 sea areas

In force now · 3

  1. NAVAREA XII 639/26 · Surveys · Bering Sea2026-09-17 · in force

    BERING STRAIT. ALASKA. 1. SCIENTIFIC MOORINGS, AT DEPTH 15 METERS, ESTABLISHED IN: A. 65-46.86N 168-34.06W. B. 65-44.75N 168-15.76W.…

    Scientific moorings, at depth 15 meters, established in: a. 65-46.86N 168-34.06W
  2. HYDROPAC 2700/26 · Surveys · Bering Sea2026-09-17 · in force

    BERING STRAIT. RUSSIA. 1. SCIENTIFIC MOORING, AT DEPTH SEVEN METERS, ESTABLISHED IN 66-19.59N 168-57.01W. 2. CANCEL HYDROPAC 1795/25.

    Scientific mooring, at depth seven meters, established in 66-19.59N 168-57.01W
  3. HYDROARC 283/24 · Surveys · Arctic Ocean2024-12-17 · in force

    BEAUFORT SEA. CHUKCHI SEA. ALASKA. DNC 27. SCIENTIFIC MOORINGS ESTABLISHED: A. BCE-24, IN 71-40.40N 154-59.90W, AT DEPTH 108 METERS, TOP FLOAT 20…

    Scientific moorings established: a. BCE-24, in 71-40.40N 154-59.90W, at depth 108 meters, top float 20 meters

How it reads in recent messages

  1. HYDROARC 250/26 · Surveys · The Northwestern Passages2026-09-23

    CANADA. SCIENTIFIC MOORINGS ESTABLISHED IN: A. 69-42.02N 095-42.64W, LEAST DEPTH 43 METERS. B. 69-36.60N 095-20.92W,…

    Scientific moorings established in: a. 69-42.02N 095-42.64W, least depth 43 meters
  2. HYDROARC 218/26 · Surveys · Kara Sea2026-09-07

    KARA SEA. RUSSIA. SCIENTIFIC MOORINGS REPORTED IN: A. 67-17.87N 072-40.37E. B. 67-20.38N 072-46.96E. WIDE BERTH REQUESTED.

    Scientific moorings reported in: a. 67-17.87N 072-40.37E
  3. AUSCOAST 202/26 · Surveys · Timor Sea2026-05-28

    21 YELLOW LIGHTBUOYS, FL Y 1.5 SEC, WITH SCIENTIFIC EQUIPMENT ATTACHED, DEPLOYED IN AN AREA BOUNDED BY 09-51S TO 10-36S AND 129-58E TO 128-43E.…

    21 yellow lightbuoys, fl y 1.5 sec, with scientific equipment attached, deployed in an area bounded by…
  4. HYDROPAC 1795/25 · Surveys · Bering Sea2025-07-14

    BERING STRAIT. RUSSIA. DNC 27. SCIENTIFIC MOORING, AT DEPTH SEVEN METERS, ESTABLISHED IN 66-19.56N 168-57.08W.

    Scientific mooring, at depth seven meters, established in 66-19.56N 168-57.08W
  5. NAVAREA XII 422/25 · Surveys · Bering Sea2025-07-14

    BERING STRAIT. ALASKA. SCIENTIFIC MOORINGS, AT DEPTH 15 METERS, ESTABLISHED IN: A. 65-46.86N 168-34.07W. B. 65-44.76N 168-15.75W.

    Scientific moorings, at depth 15 meters, established in: a. 65-46.86N 168-34.07W

Earliest in the archive

  1. NAVAREA IV 623/96 · Other · Labrador Sea1996-08-21

    CHART 110 (2ND ED). SUBSURFACE MOORINGS ESTABLISHED WITHIN 80 METERS OF SURFACE IN: A. 56-33.6N 052-39.5W. B. 55-19.5N…

    Subsurface moorings established within 80 meters of surface in: a. 56-33.6N 052-39.5W

Often in the same message

Related terms

Wide berth requested
Keep well clear — or, when a distance is given ("TWO MILE BERTH REQUESTED"), at least that far away.
HYDROARC
The U.S. long-range warning series for the Arctic Ocean.
Anchoring and fishing prohibited
Ships may pass but must not anchor, trawl or put gear on the seabed — usually because of cables, pipelines, moorings or ordnance.
Survey operations
A research or survey vessel is mapping the seabed or water column, often while towing equipment.

Warning types that use it

Counts cover the messages in this archive that use the term, recounted 2026-09-24; see coverage for what is collected and since when. Not for navigation — follow official NAVAREA and coastal broadcasts.

Scientific mooring — what it means in a navigational warning · seahazards