Golden redfish stock in the Barents Sea (Sebastes marinus)
The common redfish is classified as a threatened species. The population is small and continues to fall. Measures to improve the situation have been initiated in recent years.
What is being monitored?
Cite these dataInstitute of Marine Research (2019). Stock of golden redfish in the Barents Sea. Environmental monitoring of Svalbard and Jan Mayen (MOSJ). URL: http://www.mosj.no/en/fauna/marine/common-redfish.html
|Recruits, million individuals||103||Institute of Marine Research||6530||3520||1740||1440||1470||1420||1360||1290||1440||1310||860||890||430||350||270||300||250||130||320||220||1400||380||210||240||210||1140||2230||60||30||50||2520||4110|
|Total stock||106 kg||Institute of Marine Research||140||137||131||127||118||116||117||116||113||111||106||100||91||81||74||71||68||66||64||62||59||56||53||50||45||42||40||38||36||36||35||34|
|Mature stock||106 kg||Institute of Marine Research||70||69||65||62||56||56||59||61||63||66||66||65||61||55||52||51||50||50||49||49||48||46||44||41||38||35||32||29||27||26||24||22|
The method for estimating the stock of golden redfish is based on 2 approaches.
- First, a qualitative (non-analytical) assessment of the trends in biomass and age classes from the scientific surveys and catch data. These include surveys in the Barents Sea (in winter and summer) and along the Norwegian shelf.
- Second, an analytical assessment using the GADGET model structured to age and size. This model is based on the same data, and estimates biomass at specific ages and fishing mortality by modelling biological processes (growth, development) and fitting these to observations.
An improved model for estimating population size has begun to be formally used for the first time after being approved by the ICES in 2012. A lack of coverage of the redfish’s geographical spread and weaknesses in the expedition programme somewhat reduce the quality of the data used in the model.
Reference level and action level
The reference level is the precautionary limit for the spawning stock (not known). The action limit is when the estimated spawning stock is below the precautionary limit for the spawning stock.
Status and trend
Data from the Norwegian Institute of Marine Research expeditions and from the trawler fisheries shows a clear reduction in the population of common redfish, and the population is now at the lowest level that has ever been measured.
The population has seen little recruitment since the late 1990s. The International Council for the Exploration of the Sea (ICES) considers that the population has a reduced reproductive capacity and is now at its lowest ever level. Better recruitment in individual year-classes since 2003 led to an increase in immature stocks, while the total stock measured in tonnes fell further due to higher weights of mature redfish in the catch. There is also a risk that some of the registered fry belong to the larger beaked redfish stock, since the species are identical in appearance at the fry stage.
Given the low production of common redfish at the present time, the population is expected to remain weak for several years.
The common redfish population is affected by both natural conditions, such as sea temperature and the occurrence of fish that eat redfish, and human activity, including fishing.
The International Council for the Exploration of the Sea assesses the population to be very weak and recommends a total ban on fishing, the closure of fishing grounds and strict regulation of bycatches.
The common redfish is classified as endangered (EN) in the Norwegian Red List 2015. The spawning population is very weak and is still declining. If catches continue at the level of recent years (five thousand tonnes a year) and recruitment remains at the average level of the years 2001-2011, the model in use indicates that the population will collapse in the near future. Therefore, with an exception for a very restricted line fishery, a ban has been introduced on all direct fishing for common redfish. In addition, regulations have been introduced to prevent unwanted bycatch of redfish in other fisheries.
It is important to maintain the ban on direct fishing and that the permitted limit for bycatches is set as low as possible until a clear increase in the spawning population and young fish has been confirmed.
If the redfish population is managed responsibly, it should be possible to re-establish it. Its relative the beaked redfish is a good example of this. How quickly this can occur will also be partly dependent on the size of the fish population that eats redfish.
About the monitoring
The stock of golden redfish is at a critically low level due to previous overfishing, and the species is classified as Endangered on the Red List. It is important to monitor it to get good estimates and correct assessments of the population size to maintain sustainable fisheries in the long term.
Golden redfish live at a depth of 100–500 metres on the continental shelf, along the coast and in some places in the fjords. The species is distributed north to northwest of Spitsbergen. At an age of 2, golden redfish are 10–12 cm long, and they grow about 2 cm per year until they become sexually mature at an age 11 or 12. Golden redfish spawn free-living larvae, and are therefore viviparous. Juvenile redfish feed on zooplankton, whereas older redfish feed on krill, capelin, herring and cod. Small redfish are important food for cod and halibut.
Places and areas
Relations to other monitoring
- Monitoring programme
- International environmental agreements
- Voluntary international cooperation
- Related monitoring