The Greenland Sea borders Greenland in the south, the Arctic Ocean, Svalbard, the Norwegian Sea, Iceland and the Danish Strait. The cold and deep (> 2000 m) Greenland Sea is a relatively shallow maximum depth of 630 m in the Danish Strait. It is separated from the deeper and warmer southern Irminger Sea by a submarine sill running from east to west. Together with the Norwegian Sea, it forms the main exit point of the Arctic Ocean to the Atlantic. In the area north of these borders, the cold southward East Greenland Current (EGC) prevails in hydrographic conditions. And this is mostly made up of Norwegian Deep Water below 0 ° C.
EGC is formed in the Arctic by the cooling of the North Atlantic Water (NAW) flowing from the warmer north, taken to the North Pole by the Norwegian Atlantic Current. Warmer water enters the Greenland Sea Glow, where it cools through contact with the Arctic Ocean and associated sea ice.
Much of the Greenland Sea falls within the ICES area of the North East Atlantic Fisheries Commission (NEAFC) XIVa and IIb2. ICES provides scientific advice for fisheries in the region through the advisory committee used by relevant governing authorities such as NEAFC. Arctic zooplankton produced in the Greenland Sea migrates by sea currents to the Icelandic and Norwegian Seas and contributes to the feeding of large pelagic fish stocks. In recent years, the Greenland Sea has experienced higher temperatures due to the increased flow of North Atlantic water. This could have a significant impact on the expected yields of commercial species in the area.
Cheung predicted a 15–45% increase in maximum capture potential in the Greenland Sea between 2005 and 2050. Greenland flounder, red fish, Arctic cod, herring, blue haddock, tusk and capelin are important commercial fish species in the Greenland Sea and neighboring regions. Capelin was historically the largest fish stock in the adjacent Icelandic Sea region. However, since the mid-2000s there has been a decline in recruitment and stock size, possibly due to an increase in Atlantic water inflow.
Fishing in the Greenland Sea
The total number of fish species known from the Greenland exclusive economic zone (EEZ) is 269, while the lowest number of fish species is found in the Greenland Sea, northeast of the Greenland Sea, with 47. Targeting offshore resources off Greenland, fishing can be divided into coastal and offshore fleets. The majority of the Greenland fleet consists of around 450 large ships and a large fleet of small boats.
It is estimated that around 1,700 small vessels are distributed in a form of artisanal fishing or net fishing, mostly for private use. Fishing and other anthropogenic activities in eastern Greenland mainly take place in the southern parts. The coastal fleet consists of a variety of different platforms, from dog sleds used for ice fishing, to small multipurpose boats that use whaling or passive gears such as gillnets, pound nets, traps, combs and long lines.
The main species targeted are shrimp, Atlantic cod, lumpfish, snow crabs and salmon. Coastal fleets that hunt Atlantic cod, snow crabs, clams and shrimp are regulated by licenses, TAC, and confined spaces. Salmon and lumpfish fishing is not regulated. Besides the Greenland fleet, marine resources in Greenland waters are exploited by many countries, particularly the EU, Iceland and Norway, using long lines as well as bottom and pelagic trawls. Demersal deep sea fishing consists mainly of ships that hunt Greenland flounder, shrimp, red fish and Atlantic cod. Greenland flounder and redfish have been targeted using demersal otter trawls since 1985. Longliners operate on both the east and west coast, with Greenland halibut and Atlantic cod as target species. Bycatches are round-nosed grenades, rough-headed grenades, defensive teeth, Atlantic halibut, and Greenland sharks.
Pelagic fishing in Greenland waters is carried out in Eastern Greenland and the currently targeted species are Atlantic mackerel and pelagic redfish. There is relatively little fishing for herring in the border area between Greenland, Iceland and Jan Mayen. Additionally, Arctic cod, blue whiting, and capelin are caught by commercial fishing in the Greenland Sea and neighboring areas.
The main area of the Greenland Sea is part of the XIVa and IIb sections of the International Marine Exploration Council (ICES) and the congress area of the North East Atlantic Fisheries Commission (NEAFC). ICES provides scientific advice for fisheries in the region through the advisory committee used by relevant governing authorities such as NEAFC. Demersal and pelagic offshore fishing TAC with longlines are governed by minimum landing dimensions, gear features and irregular enclosed spaces.
There are many species of mammals and pinnipeds and capped whales that feed on open waters in the Greenland Sea, including walrus, ringed seal, bearded seal, harp seal, and hooded seal. The Greenland Sea is an important landing area for harp seals and capped seals. The hooded seal stocks in the area are quite large and have been subjected to commercial exploitation for centuries. However, this stock, which gives an estimated total population of 84,020 titled seals in 2013, is below the conservation reference point in the precautionary harvest strategy developed by ICES.
Also since 2007, the stock is protected from commercial hunting and, by contrast, the harp seal is plentiful. The total abundance for 2013 is estimated to be 627,410, and the harvest level is only around 6000 per year. Minke whales in the Norwegian Sea belong to the same creature that feeds on the Barents Sea. Minke whales cross their way to summer feeding grounds in the Barents Sea, and some remain in the Norwegian Sea.
There is very little fishing in the northern part of this region. In eastern Greenland, fishing and other anthropogenic activities take place in the southern parts of eastern Greenland. Only small-scale subsistence hunting and fishing are carried out near Ittoqqortoormiit. The Greenland Sea has a stock of about seven marine fish species, mostly harvested by commercial fishing near Iceland.
Produced in the Greenland Sea, arctic zooplankton migrates by sea currents to the Icelandic, Norwegian Seas and contributes to the feeding of large pelagic fish stocks. East Greenland drifting ice creates a unique marine habitat under climate change that has not yet been studied. Over the past decades, the Greenland Sea has experienced higher temperatures due to increased North Atlantic water flow. Cheung predicted a 15-45% increase in the maximum capture potential in the Greenland Sea from 2005 to 2050.
Greenland Halibut and Fisheries Assessment
The evaluation model for Greenland halibut is a stochastic version of the logistics overproduction model using a new combined survey index and Icelandic cpue index. The reference points derived from this model are an MSYBtrigger defined as 30% BMSY as Blim, 1.7 × FMSY as Flim and 50% BMSY. BMSY and FMSY are references inherited in the model approach. An exploratory assessment on the Greenland halibut was presented in 2015 using the GADGET (Globally Applicable Area Decomposed Generic Ecosystem Toolbox model).
The assessment method is a stochastic projection of stock that finds total allowable catch (TAC) starting from scientific acoustic measurements and leading to a probability of spawning stock biomass (SSB)
Stock valuation cannot be made for this stock due to the lack of significant restructuring since the stock collapsed in the late 1960s. Two scientific studies targeting cod are considered reliable indicators of stock status. However, they are associated with great uncertainty due to single large transports.
Gold and Beaked Red Fish
The GADGET is used to evaluate golden redfish using commercial fishing data and survey data from Icelandic and German surveys. Demersal-billed red fish, located in the east of Greenland and on the slope of Iceland, are evaluated based on trends in the survey biomass indexes from the Icelandic Autumn Study in terms of an ICES trend-based assessment approach. Supplementary data used include information on fisheries, commercial catches, and length distributions.
Northeast Atlantic mackerel
The model for Northeast Atlantic mackerel is SAM, which is the state-space evaluation model. In SAM, situations are constrained by the survival equation and follow a random walk process. The differences of random walking processes on abundance and fisheries deaths are the parameters estimated by the model. SAM is a purely statistical model in which all data sources are treated as observations, assuming a lognormal observation model.
Related variances, called observation variances, are also parameters estimated by the model. Observational variances can be used to explain how well each data source fits the model and effectively corresponds to the internal weight given by the model to different data sources. Uncertainties are estimated for all parameters and for all countries.
Author: Ozlem Guvenc Agaoglu