Anthropogenic impact: Catches of shellfish

Northern shrimp (Pandalus borealis)

Bycatch is constrained by mandatory sorting grids, and by temporary closures in areas with high bycatch of juvenile cod, haddock, Greenland halibut, redfish, and shrimp (< 15mm carapace length or < 6 cm total length). Catches have varied between 19 000 and 128 000 tonnes /year since 1977. Since the mid-1990s, a major restructuring of the fleet toward fewer and larger vessels has taken place. Since 1995, average engine size of a shrimp vessel in ICES Subareas I and II increased from 1,000HP (horse power) to more than 6,000HP in the early 2010s, and the number of fishing vessels has declined markedly. Overall catch decreased from approximately 83,000 tonnes since 2000, reflecting reduced economic profitability in the fishery. After a low of about 20,000 tonnes in 2013, catches again began to increase and reached about 34,000 tonnes in 2015, but decreased to 30,000 tonnes in 2016 and 2017. The 2017 stock assessment indicated that the stock has been fished sustainably, and has remained well above precautionary reference limits throughout the history of the fishery. Accordingly, ICES used the MSY-approach to advice a 2018 TAC of 70,000 metric tons (ICES 2017).

Geographical distribution of the stock in 2009-2015 was more easterly compared to previous years (Fig. 3.9.2.1). As results, catch levels from some of the more traditional western fishing grounds have declined. Recent reports indicate lower catch rates than would be expected given the overall good stock condition. This may be related to operation costs for a relatively small fleet to move away from more traditional fishing grounds, and to find new grounds with commercially viable shrimp concentrations.

Fig. 3.9.2.1. Shrimp density by year from inverse distance weighted interpolation (e.g. Fisher et al., 1987) between trawl stations (black dots) for the Joint Russian-Norwegian Ecosystem survey (Europe Albers Equal Area Conic projection). No map for 2016-2017 available

Fisheries for northern shrimp in the Barents Sea and waters adjacent to Spitsbergen Archipelago have been carried out since the 1950s; the Russian fishery was started in 1976. The largest catches were recorded in the mid-1980s (more than 120 thousand tons) and during 1990-1991, 2000 (approximately 80 thousand tonnes). Since 2005, total annual catch of northern shrimp in this area have remained at the 20-40 thousand tonnes level (Fig. 3.9.2.2).

Figure 3.9.2.2 Total biomass index and catch of the northern shrimp in the Barents Sea and waters around Svalbard archipelago in 1982-2017 (Zakharov, 2017 with editions)

The catch of northern shrimp by Russian vessels in 2017 was about 4 thousand tons and conducted mainly in the Central Basin, near Novaya Zemlya and Franz Josef Land.

Trawl surveys of northern shrimp stocks have been carried out in the Barents Sea since 1982. During the 2005-2016 period, the stock was relatively stable (Fig. 3.9.2.2).

In 2017, estimated total biomass (method of squares) of northern shrimp was 314.2 thousand tons; 1.5% higher than in 2016, and 8% lower than the long-term average. Annual assessments of total catch of northern shrimp in the Barents Sea and waters around Spitsbergen Archipelago can typically reach 70 thousand tons (Zakharov, 2017).

Red king crab (Paralithodes camtschaticus)

The commercial fishery for red king crab in the Russian Economic Zone of the Barents Sea has been carries out since 2004. Russian Fisheries Regulations stipulate that males with carapace width greater than or equal to 150 mm can only be caught using traps.

Heavy exploitation of the stock during 2005-2006 led to a decrease in the commercial component of the red king crab population, and reduced productivity in the fishery. In 2011, decreased fishery pressure prompted population growth, and subsequent stabilisation of the commercial stock. Total catch also increased in subsequent years (Figure 3.9.2.3); in 2016, total catch of red king crabs in Russian Economic Zone was 8.3 thousand t (Table 3.9.2.1).

Figure 3.9.2.3. Commercial stock index and the total catch of the red king crab in the Russian Economic Zone of the Barents Sea in 2006-2016 (Bakanev & Stesko, 2017)

Table 3.9.2.1. The main parameters of the red king crab Russian fishery in 2006-2016 (Bakanev & Stesko, 2017)

One of the most detailed trap surveys to assess distribution of the red king crab commercial stockwas conducted in 2013. Results from this survey indicated the densest concentrations of commercial sized male crabs (more than 1000 ind./km²) was recorded on Rybachya Bank and Kildinskaya Bank, in the eastern part of Murman Rise, and in the southern part of North Kanin Bank (Figure 3.9.2.4). In other parts of this area, the abundance of commercial sized males varied from 100 to 500 ind./km² (Figure 3.9.2.4). Subsequently, aggregations of fishable crabs shifted eastward to the western part of the Kanin-Kolguev Shallow. The most eastern extent of red king crab distribution was recorded in 2015 and 2017. Two adult individuals (male and female with clutch) in eastern Pechora Sea near Vaygach Island, and the south-western coast of Novaya Zemlya Archipelago. This change in distribution could be caused by both migration to find new food resources and climatic warming.

Figure 3.9.2.4. Distribution of the commercial stock of the red king crab (commercial males, ind./km2) in autumn 2013 in Russian Economic Zone of the Barents Sea according to assessment trap’s survey (Bakanev & Stesko, 2017).

In 2016, ten Russian vessels fished red king crabs in the eastern Barents Sea, the Murman Rise, and Kanin Bank using rectangular and trapezoidal traps. The largest catches were obtained at south-eastern Murman Rise outside the 12-mile coastal zone. In 2016, the commercial stock index for red king crab was 82.5 thousand tonnes (Table 3.9.2.1, Bakanev and Stesko, 2017).

Snow crab (Chionoecetes opilio)

The snow crab fishery carried out by Norwegian, Spanish, and Russian vessels began in international waters of the Barents Sea (Loop Hole) in 2013. Russian vessels fished crabs in this area until 2016. In 2016, Russian vessels started fishing snow crabs in Russian waters (Figure 3.9.2.5). In 2017, the Russian fishery for snow crabs was conducted only within the Russian EEZ.

Figure 3.9.2.5. Russian fishery of the snow crab location in the Barents Sea in the international waters in 2013-2016 (1) and nationality waters in 2016 (2) (Bakanev and Pavlov, 2017)

Russian vessels mainly use conical traps for the snow crab fishery. Statistics for the Russian snow crab fishery in the Barents Sea during 2013-2016 are shown in Table 3.9.2.2.

Table 3.9.2.2. Russian fishery statistics for the snow crabs in the Barents Sea during 2013-2016 (Bakanev, Pavlov, 2017)

During the 2003-2016 period of unregulated fishing in Loop Hole, the total international catch of snow crabs exceeded 55 thousand t. During 2015-2016, average daily catch declined by 10-20% from the 2014 estimate (Bakanev and Pavlov, 2017).

Decreased fishery productivity indicated significant overfishing of the Barents Sea snow crab stock. To address this situation, Russia and Norway agreed in 2016 on joint management of the snow crab fishery in the international waters (Loop Hole area) to prevent illegal, unreported, and unregulated fishing.