Management strategy and harvest control rules

The management strategy for Icelandic fish stocks, in general, is to maintain the exploitation rate at the level which is consistent with the Precautionary Approach and that generates maximum sustainable yield (MSY) in the long term.

Harvest Control Rules (HCR) are set by the managers of the fishery, in the case of Iceland by the government and are based on knowledge on the state of the stock and take account of the managers objectives, the nature of the resource and uncertainties.  The main aim HCRs is thus to:

• Decrease the risk of short term interests influencing the level of exploitation.
• Ensures that the available information on the resource are used in the most rigours manner.
• Long term sustainable yield
• Ensure that stock is above save biological limits
• Often include buffers on the amount of Catch/TAC change between fishing seasons.

Iceland was one of the first countries to set HCR for marine stocks, starting with the cod stock.  As time has progressed the management of many other important stocks is through HCRs.  The stocks that currently are subjected to HCR are cod, haddock, saithe, golden redfish, capelin, spring spawning herring, ling and tusk. HCR are reviewed once every five years.

The Marine and Freshwater Research Institute (MFRI) in Iceland and The International Council for the Exploration of the Sea (ICES) issue scientific advice on the Icelandic fisheries and the exploitation levels for individual fish stocks.

The management strategy for Icelandic cod is to maintain the exploitation rate at the rate which is consistent with the precautionary approach and that generates maximum sustainable yield (MSY) in the long term.

The annual Total Allowable Catch (TAC) is set by a Harvest Control Rule (HCR). The rule is based on the mean of the TAC in the current year (TAC_y-1/y) and 20% (HR_MGT) of the biomass of 4 year and older cod (B_4+,y) in the assessment year (y).  The TAC for the fishing year y/y+1 (September 1 of year y to August 31 of year y+1) is calculated as follows:

TAC_y/y+1 = HR_MGT * (B_4+,y + TAC_y-1/y)/2

If the spawning stock biomass (SSB) falls below 220 000 tonnes (MGT B_trigger), the HCR dictates that harvest rate shall be reduced linearly to zero based on the ratio of the SSB estimated and MGT B_trigger,  the TAC for the fishing year y/y+1 is then calculated as:

TAC_y/y+1 = HR_MGT * SSB / MGT B_trigger * (B_4+,y+ TAC_y-1/y)/2

The expected range of the realized harvest rate (HR) when following the management plan (HR_MGT ) is between 0.15 and 0.27. This HCR has been evaluated by ICES and found to be consistent with the Precautionary Approach.

In accordance with the general aims of the management strategy for cod, the HCR was adopted by the Icelandic authorities in June 2009 for a period of 5 years (Letter from the Ministry of Fisheries and Agriculture to ICES dated May 23rd, 2009).  In 2015 the plan was extended until 2020 and then again in 2020 for the years 2021-2026.

The management strategy for Iceland haddock is to maintain the exploitation rate at the rate which is consistent with the precautionary approach and that generates maximum sustainable yield (MSY) in the long term.

The Harvest Control Rule (HCR) is applied to calculate the annual total allowable catch (TAC) based on 35% (HR_MGT) of the biomass of 45cm and larger haddock in the assessment year (B_45cm+,y). The TAC for the fishing year y/y+1 (September 1 of year y to August 31 of year y+1) is calculated as follows:

TAC_y/y+1 = HR_MGT * B_45cm+,y

If the spawning stock biomass (SSB) falls below 64 400 tonnes (MGT B_trigger), the HCR dictates that harvest rate shall be reduced linearly to zero based on the ratio of the SSB estimated and MGT Btrigger, the TAC for the fishing year y/y+1 is then calculated as:

TAC_y/y+1 = HR_MGT * SSB / MGT B_trigger * B_45cm+,y

This HCR has been evaluated by ICES and found to be consistent with the precautionary approach and in accordance with the ICES MSY approach.

In accordance with the general aims of the management strategy for haddock, the HCR was formally adopted by Icelandic authorities in April 2013 for the consecutive period of 5 fishing years, starting from the 2013/14 fishing year. In 2019 the HCR was revised so that HRMGT was lowered from 0.4 to 0.35 and the MGT B_trigger was raised from 45 000 tonnes to 49 400.  This revison followed re-evaluation of the HCR by ICES in 2019.  In 2025 the HCR was again reviewed by ICES and amended so that the MGT Btrigger was raised to 64 400 tonnes and B_45cm in the assessment year rather than in the advisory year used for calculation of next year’s TAC. The HCR will be in effect for the next five fishing years, starting in 2025/2026.

The management strategy for Icelandic saithe is to maintain the exploitation rate at the rate which is consistent with the precautionary approach and that generates maximum sustainable yield (MSY) in the long term.

The Harvest Control Rule (HCR) is applied to calculate the annual total allowable catch (TAC) based on 20% (HR_MGT) of the biomass of age 4 and older saithe in the assessment year (B_4+,y). The TAC for the fishing year y/y+1 (September 1 of year y to August 31 of year y+1) is calculated as follows:

TAC_y/y+1 = HR_MGT * B_4+,y

If the spawning stock biomass (SSB) falls below 67 000 tonnes (MGT B_trigger), the HCR dictates that harvest rate shall be reduced linearly to zero based on the ratio of the SSB estimated and MGT Btrigger, the TAC for the fishing year y/y+1 is then calculated as:

TAC_y/y+1 = HR_MGT * SSB / MGT B_trigger * B_4+,y

The HCR has been evaluated by ICES and found to be consistent with the precautionary approach.

In accordance with the general aims of the management strategy for saithe, the HCR was formally adopted by Icelandic authorities in April 2013 for the consecutive period of 5 fishing years, starting from the 2013/14 fishing year. In 2019 the HCR was revised so that the MGT B_trigger was lowered from 65 000 tonnes to 61 000.  The HCR was reviewed again by ICES and the HCR was amended accordingly and will be in force for the next five consecutive fishing years, starting in 2025/2026.

The management strategy for golden redfish is to maintain the exploitation rate at the rate which is consistent with the precautionary approach and that generates maximum sustainable yield (MSY) in the long term.

According to the Harvest Control Rule (HCR) the TAC for the following year (y+1) should be based on a fishing mortality of 0.112 (F_MGT) .

If the spawning stock biomass (SSB) falls below 220 000 tonnes (MGT B_trigger), the HCR dictates that fishing mortality shall be reduced linearly to zero based on the ratio of the SSB estimated and MGT B_trigger, the fishing mortality for the following year (y+1) is then calculated as:

F_y+1 = F_MGT* (SSB_y/MGT B_trigger)

The HCR has been evaluated by ICES and found to be consistent with the precautionary approach conforms to the ICES MSY approach.

In accordance with the general aims of the management strategy for golden redfish, the HCR was formally adopted by Icelandic and Greenlandic authorities in 2014.

The management strategy for Icelandic summer-spawning herring is to maintain the exploitation rate at the rate which is consistent with the precautionary approach and that generates maximum sustainable yield (MSY) in the long term.

According to the Harvest Control Rule (HCR) the TAC for the fishing year y/y+1 (1 September of year Y to 31 August of year y+1) as 19% (HR_MGT) of the biomass of herring age 4 and older (B_4+,y) in the assessment year (y) calculated as:

TAC_y/y+1 = HR_MGT* B_4+,y

If the spawning stock biomass (SSB) falls below 273 000 tonnes (MGT B_trigger), the HCR dictates that harvest rate shall be reduced linearly to zero based on the ratio of the SSB estimated and MGT B_trigger, the TAC for the fishing year y/y+1 is then calculated as:

TAC_y/y+1 = HR_MGT* (SSB_y/MGT B_trigger) * B_4+,y

The HCR has been evaluated by ICES and found to be consistent with the precautionary approach conforms to the ICES MSY approach.

In accordance with the general aims of the management strategy for summer-spawning herring the HCR was formally adopted by Icelandic authorities in June 2017.  The HCR was reviewed by ICES in 2024 and amended accordingly and will be in force for five consecutive fishing years, starting in 2024/2025.

The management strategy for Icelandic ling is to maintain the exploitation rate at the rate which is consistent with the precautionary approach and that generates maximum sustainable yield (MSY) in the long term.

According to the Harvest Control Rule (HCR) the TAC for the fishing year y/y+1 (1 September of year Y to 31 August of year y+1) is calculated in the following manner:

The advice fishing mortality that is applied from 01 September in year Y to 31 August in year Y+1, is calculated from the harvest control rule (HCR) as:

F_y/y+1= min(SSB_y/MGT B_trigger,1)*F_MGT

To calculate the catch in the last four months of the year Y (September through December), the following F is used in the year y:

F_y=(⅔F_SQ)+(⅓F_MGT)

In year Y+1, F_y/y+1 is used.

Finally, the catch advice for the year Y/Y+1 is calculated using the following formula:

C_y/y+1=(⅓C[F_y])+( ⅔C[F_y/y+1])

where the catch C[.] is calculated using the Baranov catch equation with the corresponding biomass, natural mortality, and fishing mortality values in each year. F_MGT=0.3 and MGT B_trigger = 11 100

The HCR has been evaluated by ICES and found to be consistent with the precautionary approach conforms to the ICES MSY approach.

In accordance with the general aims of the management strategy for ling, the HCR was formally adopted by Icelandic authorities in June 2017 for the consecutive period of 5 fishing years, starting from the 2017/18 fishing year. The HCR was reviewed by ICES in 2022 and amended accordingly and will be in force for five consecutive fishing years, starting in 2023/2024.

The management strategy for Icelandic tusk is to maintain the exploitation rate at the rate which is consistent with the precautionary approach and that generates maximum sustainable yield (MSY) in the long term.

According to the Harvest Control Rule (HCR) the TAC for the fishing year y/y+1 (1 September of year Y to 31 August of year y+1) is calculated in the following manner:

The advice fishing mortality that is applied from 01 September in year Y to 31 August in year Y+1, is calculated from the harvest control rule (HCR) as:

F_y/y+1= min(SSB_y/MGT B_trigger,1)*F_MGT

To calculate the catch in the last four months of the year Y (September through December), the following F is used in the year y:

F_y=(⅔F_SQ)+(⅓F_MGT)

In year Y+1, F_y/y+1 is used.

Finally, the catch advice for the year Y/Y+1 is calculated using the following formula:

C_y/y+1=(⅓C[F_y])+( ⅔C[F_y/y+1])

where the catch C[.] is calculated using the Baranov catch equation with the corresponding biomass, natural mortality, and fishing mortality values in each year. F_MGT=0.23 and MGT B_trigger = 4 800.

The HCR has been evaluated by ICES and found to be consistent with the precautionary approach conforms to the ICES MSY approach.

In accordance with the general aims of the management strategy for tusk, the HCR was formally adopted by Icelandic authorities in June 2017 for the consecutive period of 5 fishing years, starting from the 2017/18 fishing year. The HCR was reviewed by ICES in 2022 and amended accordingly and will be in force for five consecutive fishing years, starting in 2023/2024.

The management strategy for capelin is to maintain the spawning stock biomass above safe biological limits which are consistent with the precautionary approach.

According to the Harvest Control Rule (HCR) an initial quota is set following the rule developed by ICES, with a very low probability of being higher than a regression estimated final TAC. This is followed by an intermediate TAC set in the autumn and a final TAC set in winter, that will have a >95% probability of SSB being greater than or equal to B_lim at spawning time in the following spring.

The Coastal states, Iceland, Greenland and Norway, have agreed (Coastal State Consultations, 2015) to use the HCR as the basis for management. In 2023 the HCR was reviewed by ICES and based on that review the HCR was amended and will be in force for the next five seasons, starting with the 2024 season.