Age at first reproduction has declined markedly for Barents Sea cod over recent decades. In the 1940s, a cod typically reproduced for the first time when it was between 9 or 10 years old. In the 1990s, average age at first reproduction had declined to between 6 and 7 years. Reduced age at maturity may affect the reproductive capacity of the cod stock, and the cod’s role as an important top predator in the ecosystem. The possible explanation for the declining age at
Information about species composition in Norwegian fisheries north of 67N is made available through the Norwegian reference fleet (NRF), i.e., 20 high-seas vessels and 20 coastal fishing vessels which have been contracted by the Institute of Marine Research to provide fishery statistics. Table 4.4.1 shows the species composition (percent of total catch by weight) for trawl and longline fisheries conducted by the NRF during 2013. Such fishery data are now routinely collected by these vessels on a daily basis.
Greenland halibut is mainly fished in directed trawl and longline fisheries in slope areas of the continental shelf. This species is also taken as bycatch in other groundfish fisheries across the Barents Sea (Figure 4.4.3). During 1992-2009, directed fisheries for Greenland halibut were banned in the Barents Sea. During the last 10 years, average annual landings have been around 17,000 metric tons (Figure 4.4.3). Given the condition of the stock and lack of available information, ICES has recommended that
The resilience of the Barents Sea ecosystem, even unexploited, may be low due to great climatic changes (Loeng and Drinkwater, 2007), variability in primary production and biomass/production of organisms at different trophic levels. Heavily exploited populations of top predators influence many lower trophic levels of the ecosystem. Overfishing of small pelagic fish, i.e. capelin, results in imbalance of energy flow passing to the higher trophic levels; this may have the similar strong consequences for the ecosystem as overfishing of top predators (Yaragina and Dolgov, 2009).
For economic reasons, there has been little interest to develop a substantial fishery for polar cod. In recent years, the existing fishery has been conducted at a very low level relative to the stock size. Such a low level of exploitation is unlikely to influence the stock condition. Concentrations of polar cod are fished in late autumn during southward spawning migrations along the coast of Novaya Zemlya. In recent years, only Russian fishers have participated in this fishery. No fishery at all was conducted during 2012-2013, however.
Annual landings of Northeast Arctic cod, haddock, and saithe for the Barents Sea are presented in Figures 4.3.1, 4.3.3 and 4.3.16 (Subchapter 4.3.5). The fishery for Northeast Arctic cod is conducted both by an international trawler fleet operating in offshore waters and by vessels using gillnets, longlines, handlines, and Danish seines operating in both offshore and coastal areas; 60-80% of annual landings are from trawlers. The regulated minimum landing size for cod is 44cm, and the maximum
The stock of snow crabs in the Barents Sea has potential to support a fishery comparable in value to the famous cod fishery. Since the first Snow crabs were discovered in the Eastern Barents Sea in the mid 1990s
There was no fishery for capelin in the area during 2004-2008 due to poor stock condition, but during 2009-2013 the stock was sufficiently sound to support a quota between 200,000 and 400,000 metric tons. Annual landings of Barents Sea capelin are presented in Figure 4.3.12. Since 1979, the capelin fishery has been regulated through quotas set using a harvest control rule enforced by the Norwegian-Russian Fishery Commission. The harvest control rule is considered by ICES to be in accordance
Substantial removals make fishing the human activity that has the largest impact on fish stocks and functioning of the entire Barents Sea ecosystem. A fishery is not considered sustainable if it impairs recruitment potential of the stock. Single species management often focuses on measuring status of the fishery in relation to benchmarks called biological reference points (BRPs). BRPs for single species management are usually defined in terms of the fishing mortality rate (F) with target and limit reference points, and total- or spawning stock biomass (TSB or SSB).
In the area east of 26°E and south of 71°30’N, and in Russian waters of the Barents Sea, the commercial crab fishery is managed to achieve long-term sustainability by setting annual quotas for this area. Outside this area (west of 26°E), the red king crab fishery is regarded as undesirable; a free non-legislated fishery is permitted, and release of viable crabs back into the sea is prohibited. In the Norwegian waters of the Barents Sea, the harvest rate of this species in the quota-regulated area is high;
Three species of wolffish: Atlantic wolffish (Anarhichas lupus); spotted wolffish (Anarhichas minor); and northern wolffish (Anarhichas denticulatus) are taken mostly as bycatch in fisheries for gadoids in the Barents Sea. Although wolffish are sometimes the dominant catch in longline fisheries, total catch of these species is relatively small (Figure 4.4.4).
The 2013 saithe assessment was not accepted by ICES, but national advice was provided to Norwegian authorities by IMR. SSB has decreased in recent years, and fishing mortality has increased (Figure 4.3.53). The 2014 TAC was set at 119,000 tonnes based on national advice; this represents a 15% reduction from 2013 (ICES AFWG, 2014).
Norwegian and Russian vessels exploit the stock over the entire resource area, while vessels from other nations are restricted to the Svalbard fishery zone. No overall TAC has been established for this stock, and the fishery is partly regulated by effort control, licensing, and a partial TAC (Russian zone only). Bycatch is constrained by mandatory sorting grids and by temporary closures of areas where high bycatch occurs of juvenile cod, haddock, Greenland halibut, redfish, or small shrimp (< 15 mm). The minimum mesh size is 35 mm.
The stock of beaked redfish in ICES Subareas I and II, also called the Norwegian-Barents Sea stock, is found in the northeast Arctic from 62ºN in the south to the Arctic ice north and east of Spitsbergen (Figure 4.4.2). The southern limit of its distribution is not well defined, but is believed to be somewhere on the slope northwest of Shetland; the abundance of this species decreases south of this latitude. Nonetheless, the 62ºN boundary defines the management unit more so than biological stock
Based on the most recent estimates of SSB (Figure 4.3.40), ICES classifies the stock as having full reproductive capacity, but also in danger of being harvested unsustainably. Fishing mortality has fluctuated around FMSY (0.35) during the last 10 years, but has increased considerably since 2010 and is now above Fpa. Very strong year classes (2004-2006) recruited to the fishable stock in 2008-2010; thus, the stock in 2010-2011 reached the highest level observed in the time series that goes back to
Although discarding is prohibited for fisheries conducted in the Barents Sea, inevitably some discarding does occur; the level of which is not reported. Hence, estimates of discard are not incorporated in fish stock assessments. Lack of discard estimates results in stock assessments which are less precise, less accurate, and less reliable. Hence, the impact of fisheries on the ecosystem is not fully understood. One possible approach to estimate the amount of discarded fish is to analyze landings data, i.e.,
Annual landed catch of golden redfish in the Barents Sea was approximately 7,000 metric tons during 2004-2010, and decreased to approximately 5,500 metric tons during 2011-2013. No limit reference points have been suggested or adopted for this species. Estimated SSB has been decreasing since the 1990s, and is currently at the lowest level in the time-series. Estimates of fishing mortality have been increasing since 2005; the current F is the highest level in the time-series (Figure 4.4.2).