---
title: "K.J. Hedges reports Greenland halibut caught during 2025 trawl survey in Subarea 0; 0B biomass 212,000 t."
sdDatePublished: "2026-08-08T14:34:00Z"
source: "https://www.nafo.int/Portals/0/PDFs/sc/2026/scr26-021.pdf"
topics:
  - name: "scientific research"
    identifier: "medtop:20000735"
locations:
  - "Greenland"
  - "Canada"
---


K.J. Hedges reports Greenland halibut caught during 2025 trawl survey in Subarea 0; 0B biomass 212,000 t.

Report on Greenland halibut (Reinhardtius hippoglossoides) caught during the 2025 trawl survey in Subarea 0

Serial No. N7740

NAFO SCR Doc. 26/021

SCIENTIFIC COUNCIL MEETING –JUNE 2026

Northwest Atlantic Fisheries Organization

www.nafo.int
Report on Greenland halibut (Reinhardtius hippoglossoides) caught during the 2025 trawl survey in
Subarea 0
K.J. Hedges1
1Fisheries and Oceans Canada, Freshwater Institute, 501 University Cres., Winnipeg, Manitoba, Canada R3T
2N6

2026-06-08
Hedges, K.J. 2026. Report on Greenland halibut (Reinhardtius hippoglossoides) caught during the 2025 trawl
survey in Subarea 0. NAFO Scientific Council Research Document, SCR Doc. 26/021: 1-51.
Abstract
A stratified-random otter trawl survey was conducted in Divisions 0A and 0B in fall 2025. The survey took
place from October 19 to November 20, 2025. A Bacalao trawl was used with the R.V. Tarajoq. Survey stations
were randomly located within depth strata in Divs. 0A and 0B. Near-bottom temperatures were similar to
previous surveys varying between -0.81 to 1.57∘C in Div. 0A and -0.33 to 4.16∘C in Div. 0B. The highest mean
temperature was in the 601-800 m stratum and the coldest mean was in the 201-400 m stratum in Div. 0A,
and the highest mean temperature was in the 801-1000 m stratum and the coldest mean was in the 201-400
m stratum in Div. 0B. Greenland halibut were distributed throughout the survey area. A majority of both
females (94.34%) and males (88.7%) were immature in Division 0A, but the ratios were more balanced in 0B,
where 48.65% and 35.74% of females and males, respectively, were immature. The 2025 biomass estimates
for 0A and 0B were 8.59e+04 t (S.E. 1.21e+04) and 2.12e+05 t (S.E. 6.32e+04), respectively. The 2025
abundance estimates for 0A and 0B were 1.19e+08 (S.E. 1.90e+07) and 1.51e+08 (S.E. 3.25e+07),
respectively. These biomass and abundance values cannot be compared directly with the 1999-2017 time
series from the R.V. Pâmiut because a calibration is not available to account for the changes in vessel and
gear, and revisions to survey strata that were applied in 2022.
Introduction
A depth-stratified random multi-species bottom trawl survey was conducted in southern Division 0A (0A-
South; to approximately 72.5∘N) and Div. 0B in Northwest Atlantic Fisheries Organization Subarea 0 using the
R.V. Tarajoq during October 19 to November 20, 2025. Surveys during 2022-2025 used a Bacalao trawl;
previous surveys during 1999-2019 used an Alfredo III trawl with the R.V. Pâmiut (1999-2017) and F.V.
Helga Maria (2019). The survey stratification was altered in 2022 by adding a 201-400 m depth stratum to
the existing strata (401-600, 601-800, 801-1000, 1001-1200, 1201-1400, 1401-1500 m). With the changes in
vessel, gear, and stratification in 2022, without calibration experiments, data from 2022-2025 represent a
new time series from the data collected during 1999-2019.

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Deep-water surveys in 0A-South started in 1999 and were completed every second year between 2004 and
2014, then annually between 2015 and 2017. Surveys in 0B were less frequent, occurring in 2000, 2001, 2011
and 2013 to 2016. These surveys were all completed using the R.V. Pâmiut. Following retirement of the
R.V.Pâmiut in 2018 the F.V. Helga Maria was used to conduct a survey of 0A-south in 2019, but post-survey
analysis identified significant differences in trawl performance below 700 m, therefore the data were not
accepted for assessing the status of the NAFO Subarea 0 stock. In 2022, surveys in 0A-south and 0B resumed
using the R.V. Tarajoq (Table 1). Detailed descriptions of changes in survey coverage, timing, vessel and gear
are provided in HEDGES (2023).
The survey objectives are to: 1) Collect data required to establish age structure and estimate the population
abundance, biomass, and recruitment of Greenland halibut; 2) Record numbers caught and collect length and
weight data on all other commercial species to support by-catch monitoring through the calculation of
abundance and biomass indices, and size structure of individual species; 3) Record numbers and collect
weight data on all non-commercial species caught to allow calculation of abundance and biomass indices for
individual species; 4) Collect additional data and biological samples as desired and as time permits
(e.g. lengths for by-catch, maturity information, coral samples, other special requests); 5) Calculate total
biomass caught per tow and per survey as an index of overall ecosystem productivity; 6) Collect temperature
data at each fishing station.
Table 1.
Survey locations, dates, vessels and gear used since 1999 in NAFO Subarea 0.
Year
0A-North
0A-South
0B
Vessel
Gear
Accepted
1999

X

R.V.
Pâmiut
Alfredo III
Y
2000

X
R.V.
Pâmiut
Alfredo III
Y
2001

X
X
R.V.
Pâmiut
Alfredo III
Y
2002

2003

2004
X
X

R.V.
Pâmiut
Alfredo III
Y
2005

2006

X

R.V.
Pâmiut
Alfredo III
Y
2007

2008

X

R.V.
Pâmiut
Alfredo III
Y
2009

2010
X
X

R.V.
Pâmiut
Alfredo III
Y
2011

X
R.V.
Pâmiut
Alfredo III
Y
2012
X
X

R.V.
Pâmiut
Alfredo III
Y
2013

X
R.V.
Pâmiut
Alfredo III
Y
2014

X
X
R.V.
Pâmiut
Alfredo III
Y
2015

X
X
R.V.
Pâmiut
Alfredo III
Y

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Northwest Atlantic Fisheries Organization

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Year
0A-North
0A-South
0B
Vessel
Gear
Accepted
2016

X
X
R.V.
Pâmiut
Alfredo III
Y
2017

X

R.V.
Pâmiut
Alfredo III
Y
2018

2019

X

F.V. Helga
Maria
Alfredo III
N
2020

2021

2022

X
X
R.V.
Tarajoq

Y
2023

X
X
R.V.
Tarajoq

Y
2024

X
X
R.V.
Tarajoq

Y
2025

X
X
R.V.
Tarajoq

Y
Methods
Stratification and Set Selection
A depth stratification scheme similar to that used by the Greenland Institute of Natural Resources for the
Division 1CD survey was developed in 2008 to facilitate comparisons between surveys conducted in Canadian
and Greenland waters. The depth bins were redefined in 2022 using updated bathymetric data, resulting in
slight differences from the depth bins used in surveys conducted between 1999 and 2019. Therefore, sets
completed during 1999-2019 were re-assigned to the new depth strata post-hoc to allow consistent spatial
extrapolation when calculating abundance and biomass indices across years (Figures 1, 2 and 3, and Table 2).
Previous revisions to the survey strata and changes to earlier index calculations are described in TREBLE
(2020).

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Northwest Atlantic Fisheries Organization

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Figure 1.
Map of NAFO areas and survey strata.

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Northwest Atlantic Fisheries Organization

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Figure 2.
Stratification scheme for Division 0A-South.

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Northwest Atlantic Fisheries Organization

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Figure 3.
Stratification scheme for Division 0B.

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Northwest Atlantic Fisheries Organization

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Table 2.
Survey stratification scheme for NAFO Subarea 0.
Survey
Area
Stratum
Depth
Stratum
(m)
Area
(km2)
Assigned
Sets
(1/750
km2)
0A
A1-3
201-400
2,441.00
2
0A
A1-4
401-600
2,151.56
5
0A
A1-5
601-800
794.75
5
0A
A1-6
801-1000
603.81
5
0A
A1-7
1001-1200
745.21
5
0A
A1-8
1201-1400
812.76
2
0A
A2-3
201-400
5,095.00
2
0A
A2-4
401-600
4,649.39
4
0A
A2-5
601-800
2,250.41
2
0A
A2-6
801-1000
1,144.81
2
0A
A2-7
1001-1200
1,873.10
3
0A
A2-8
1201-1400
2,151.49
3
0A
A2-9
1401-1500
1,153.19
2
0A
A3-3
201-400
1,950.00
2
0A
A3-4
401-600
784.79
2
0A
A3-5
601-800
759.93
2
0A
A3-6
801-1000
1,020.40
2
0A
A3-7
1001-1200
1,306.99
2
0A
A3-8
1201-1400
1,145.95
2
0A
A4-3
201-400
3,926.00
2
0A
A4-4
401-600
1,921.58
2
0A
A4-5
601-800
2,483.22
3
0A
A4-6
801-1000
1,375.61
3
0A
A4-7
1001-1200
1,635.65
2
0A
A4-8
1201-1400
1,071.88
2
0B
B1-1000
1001-1200
6,585.63
7
0B
B1-1200
1201-1400
4,753.85
6
0B
B1-1400
1401-1500
1,964.57
2
0B
B1-200
201-400
11,285.00
16
0B
B1-400
401-600
17,396.93
16
0A
B1-600
601-800
2,282.96
2
0B
B1-600
601-800
2,282.96
8
0B
B1-800
801-1000
8,053.13
10
0B
B2-200
201-400
25,879.00
24
The survey area between 200 and 1500 m in Div. 0A-South (to approximately 72∘N) is 47,924 km2 (Table 1)
within which 79 sets are randomly assigned to 28 sub-strata (4 sub-stratum in each of 7 depth strata). In Div.
0B, 110 survey stations are divided among 8 sub-strata (2 sub-strata within the 201-400 m depth stratum; all
other depth strata are not subdivided). Set selection is based on a coverage level of approximately 1 set per
750 km2. A minimum of two sets are randomly selected from numbered units within each sub-stratum using a

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buffered random design (KINGSLEY (2004)). If a set cannot be fished due to bad bottom, ice, etc. then the
tow is taken in an adjacent unit as close to the missed site within the sub-stratum as feasible given the
conditions. When this is not possible the tow may be re-located to an area of the sub-stratum where there are
“holes” in the set coverage and a unit location selected at random from those available in that area.
Vessel and Gear
The surveys prior to 2019 were conducted by the RV Pâmiut, a 1084 GRT stern trawler measuring 53 m in
length. An Alfredo III bottom otter trawl with rock hopper ground gear was used. Mesh size was 140 mm with
a 30 mm mesh liner in the cod end. Trawl doors were Injector International, measuring 7.5 m2 and weighing
2800 kg. These doors replaced the Greenland Perfect doors (9.25 m2 and 2420 kg) in 2004. The average net
height was 20 cm higher with the new doors but the overall net performance was not significantly different
(95% level) (Jørgensen personal communication). More information about the trawl and gear can be found in
JØRGENSEN (1998). A Furuno based system mounted on the head rope measured net height and was used to
determine bottom contact and the start/finish of each tow. Scanmar sensors measured the distance between
the trawl doors and since 2010 the wingspread.
The 2019 survey vessel, FV Helga Maria, was 1470 GRT and 57 m in length. The trawl gear and rigging as
described above remained unchanged. The warps, bridle, ground gear and distance from the hanging blocks
were kept the same as on the RV Pâmiut. The fishing procedures were also the same, the RV Pâmiut captain
and crew were involved prior to and during the survey. See Novaczek WHEELAND L. J. and Nogueira (2020)
for additional information on vessel comparison and gear performance.
Since 2022 the survey has been conducted using the RV Tarajoq, which is a 2841 GRT and 61.4 m long stern
trawler. The RV Tarajoq used a Bacalao trawl but followed the same fishing procedures as the RV Pâmiut and
had the same captain and crew.
Oceanographic Sampling
A Seabird 19 CTD (conductivity, temperature and depth recorder) was mounted on the head-rope beginning
in 2010 and was used to determine temperature, depth and time spent on the bottom. In the few cases where
there were no data from the CTD, data from the Furuno trawl eye sensor was used to determine bottom
temperature.
Two oceanographic lines that cross the shelf and slope at Broughton Island (near 68∘N) and Cape Christian
(near 71∘N) were included in survey plans prior to 2022. These transect lines were completed when
conditions (time and ice) allowed. The transect lines were removed from the survey design in 2022 because
they had not been completed in most years. The trawl mounted CTD continues to provide temperature and
salinity data at the trawl mouth to associate environmental conditions with trawl catches. In addition, in 2017
an annual ecosystem-foc