Year | Number of vessles | Catch |
|---|---|---|
1996 | 2 | 22 |
1997 | 6 | 1 159 |
1998 | 8 | 992 |
1999 | 7 | 497 |
2000 | 6 | 224 |
2001 | 3 | 19 |
2002 | 7 | 19 |
2003 | 1 | 2 |
2004 | 1 | 2 |
2005 | 1 | 2 |
2006 | 2 | 8 |
2007 | 2 | 23 |
2008 | 2 | 15 |
2009 | 3 | 35 |
2010 | 23 | 2 600 |
2011 | 20 | 1 425 |
2012 | 21 | 533 |
2013 | 16 | 529 |
2014 | 15 | 549 |
2015 | 14 | 466 |
2016 | 11 | 230 |
2017 | 10 | 160 |
2018 | 7 | 114 |
2019 | 12 | 140 |
2020 | 12 | 117 |
2021 | 11 | 92 |
2022 | 10 | 55 |
2023 | 13 | 57 |
2024 | 15 | 123 |
Key Signals.
The directed Norway redfish fishery peaked 2010 when it was 2 600 t but declined thereafter; recent annual landings (2017–2024) stabilized at around 110 t.
Survey biomass indices have markedly increased since 2011, reaching record-high levels post-2016, driven by stronger recruitment between 2003 and 2012.
No analytical stock assessment is performed due to insufficient data. Advice follows ICES rfb-rule for data-limited stocks, incorporating biomass trends, exploitation patterns, and precautionary safeguards for slow-growing species.
The TAC has been substantially under-utilized since its implementation in 2013/2014, with only 6–19% of available quota landed in recent years.
GENERAL INFORMATION
Norway redfish (Sebastes viviparus) is the smallest of the three Sebastes species found in Icelandic waters, rarely reaching length over 30 cm. Norway redfish is distributed around Iceland with highest densities along the south and southwest coast of Iceland at depths ranging from 40 to 400 m. Little is known about the biology of the species but as with other redfish species in Icelandic waters the Norway redfish is slow-growing and long-lived.
The fishery
A directed fishery for Norway redfish in Icelandic waters started in 1997 with landings of 1 200 t (Figure 1 og Table 1). The catches declined rapidly and between 2001 and 2009 only a few tonnes were landed annually. In 2010, a directed fishery started again with total landings of 2 600 t. Landings have since then declined and annual landings in 2017–2024 were on average around 110 t. Landings in 2024 were 128 t. Norway redfish is caught by demersal trawlers. The number of trawlers landing most of the species have been between 7 to 15 in recent ten year (Table 1).
The main fishing grounds for Norway redfish are southeast and south of Iceland (Figure 2 og Figure 3). Small portions are taken along the Reykjanesridge. Norway redfish is mainly caught at depths between 100 and 400 m (Figure 4).
CATCH PER UNIT EFFORT (CPUE) AND EFFORT
CPUE estimates of Norway redfish in Icelandic waters are not considered representative of stock abundance as changes in fleet composition and technical improvements have not been accounted for when estimating CPUE.
Non-standardized estimates of CPUE in demersal trawl (kg/h), in hauls where redfish was more than 10% of the catch, decreased from about 2 700 kg/h to 1 200 kg/h in 1997–2000 (Figure 5). In 2010, when the fishery commenced again, CPUE was about 1 300 kg/h but decreased and has in recent nine years fluctuated between 500–1 000 kg/h. Total fishing effort (number of towing hours decreased between 1997 and 2000 but increased rapidly in 2010 when target fishery started again. Since 2010, fishing effort has steadily decreased and was in 2017–2024 the lowest in the time series. The decrease in effort is due to decrease in the targeted fishery towards Norway redfish.
Survey data
Figure 6 shows the total biomass and recruitment indices (fish smaller than 15 cm) from the Icelandic spring groundfish survey (IS-SMB), which has been conducted annually in March 1985–2025, and Icelandic autumn groundfish survey (IS-SMH), which has been conducted annually in March 1996–2024. Both surveys cover the main distribution of Norway redfish in Icelandic waters, but IS-SMB is used when calculating advice. The total biomass index has increased rapidly since 2011 and has since 2016 been the highest recorded and more than three times higher than in 2000. The index in recent years is largely dominated by a few large hauls, causing high variance.
The juvenile abundance index for individuals smaller than 15 cm indicates stronger recruitment in 2003–2012 compared to other years (Figure 6).
Length distributions from IS-SMB and IS-SMH show that the modes are between 20 and 25 cm (Figure 7 and Figure 8). The increased abundance of fish smaller than 15 cm can be observed in 2003–2012 and this fish has contributed to increased stocks size of Norway redfish since 2008. Small Norway redfish smaller than 20 cm were observed in the surveys since 2018.
Norway redfish in the surveys is found all around Iceland but is most abundant along the south and south¬west of Iceland (Figure 9). In recent years, the abundance in the West area has increased and since 2015 majority of the Norway redfish biomass was measured in that area. It is mostly caught at 100–400 m depth, but is most abundant at 200–300 m (Figure 10).
Stock assessment
No analytical assessment is conducted on this stock due to lack of data.
Basis for the advice
Norway redfish is considered a data limited stock (DLS) and follows the ICES framework for such (Category 3.2; ICES 2012). Below is the description of the formulation of the advice.
The advice is based on ICES rfb-rule for data limited stocks and this is the first time. The method takes into account life history traits, exploitation characteristics and other relevant parameters for data-limited stocks (ICES 2021). The rfb-rule has the following form:
\[ A_{(y+1)}=A_y \times r \times f \times b \times m \] where \(A_{y+1}\) is the advised catch, \(A_y\) is last years advice, \(r\) corresponds to the trend in biomass index (as in the current ICES “2 over 3” rule), \(f\) is a proxy for the exploitation (mean catch length divided by an MSY reference length) and \(b\) a biomass safeguard (reducing the catch when biomass index drops below a trigger value).
\(r\) is the ratio of the mean of the last two survey indices and the mean of the three preceding values or:
\[ r = \frac{\sum_{i=y-2}^{y-1} I_1 / 2}{\sum_{i=y-3}^{y-5} I_1 /3} \]
\(f\) is the length-ratio component where:
\[ f= \frac{\bar{L}_{(y-1)}}{L_{(F=M)}} \]
where \(\bar{L}\) is the mean catch length above target reference length, \(L_{(F=M)}\), which is calculated as:
\[ L_{(F=M)}=0.75L_c+0.25L_\infty \] where \(L_c\) is the length where frequency is half that of the modal value, and \(L_\infty\) is from von Bertalanffy growth equation.
\(b\) is the biomass safeguard and is used to reduce catch advice when the last year’s index falls below trigger:
\[ b=min(1,I_{y}-1/I_{trigger}) \] where \(I_{trigger} = I_{loss}*1.4\) and \(I_y\) is the latest index value.
\(m\) is a multiplier based on stock growth. \(K\) for Norway redfish is \(K{<}0.2\) (slow growing) and therefore m is set as \(m=0.95\).
Reference Point | Value |
Index A | Mean index in SMB of the last two years |
Index B | Mean index in SMB of the three years prior |
Linfty | 36 cm |
Lc | 20 cm |
LF=M | 24 cm |
Multiplier, m | 0.95 |
Iloss | 6765 |
Itrigger | 9471 |
Application of rfb-rule
The total biomass index from the Icelandic spring groundfish survey (IS-SMB) was used for the stock development for Norway redfish (Figure 11).
The lowest index or the \(I_{loss}\) for Norway redfish was set to the second lowest value in the times series (1990). \(I_{trigger}\) is \(I_{loss} * 1.4\) (Figure 11)
Figure 12 shows the mean length in the commercial catches. \(L_{F=M}\) is \(23.1\) cm. Note that length samples from the fishery are scarce and data were not available in some years.
No age data are available for Norway redfish. \(L_\infty\) was therefore defined as the average observed maximum length in the survey and the 99th quantile of the length distribution in the survey (Figure 13).
Norway redfish but like other redfish species it is considered slow growing. \(m\), tuning parameter, for slow growing species (with von Bertalanffy \(K{<}0.2\)), m equals to \(0.95\).