17/18: LME FACTSHEET SERIES HUDSON BAY COMPLEX LME tic LMEs Arc HUDSON BAY COMPLEX SEA LME 18 of Map Russia LME Baffin Island (Canada) Canada Hudson Bay Iceland Newfoundland & Greenland Labrador 17 "1 ARCTIC LMEs Large ! Marine Ecosystems (LMEs) are defined as regions of work of the ArcNc Council in developing and promoNng the ocean space of 200,000 km² or greater, that encompass Ecosystem Approach to management of the ArcNc marine coastal areas from river basins and estuaries to the outer environment. margins of a conNnental shelf or the seaward extent of a predominant coastal current. LMEs are defined by ecological Joint EA Expert group criteria, including bathymetry, hydrography, producNvity, and PAME established an Ecosystem Approach to Management tropically linked populaNons. PAME developed a map expert group in 2011 with the parNcipaNon of other ArcNc delineaNng 17 ArcNc Large Marine Ecosystems (ArcNc LME's) Council working groups (AMAP, CAFF and SDWG). This joint in the marine waters of the ArcNc and adjacent seas in 2006. Ecosystem Approach Expert Group (EA-EG) has developed a In a consultaNve process including agencies of ArcNc Council framework for EA implementaNon where the first step is member states and other ArcNc Council working groups, the idenNficaNon of the ecosystem to be managed. IdenNfying ArcNc LME map was revised in 2012 to include 18 ArcNc the ArcNc LMEs represents this first step. LMEs. This is the current map of ArcNc LMEs used in the This factsheet is one of 18 in a series of the ArcDc LMEs. OVERVIEW: HUDSON BAY COMPLEX LME The Hudson Bay (HB) complex is a large, Canadian inland sea with typical Arcc characteris=cs, including cold, dilute waters and complete, seasonal ice cover. Situated between 51° and 71°N la=tude and 65° and 95°W longitude, it has a sea surface area of 1,242,000 km² and island surface area of 83,000 km². The basin is enclosed by Baffin Island and the Canadian mainland. Its main opening is to the Labrador Sea (North Atlan=c) via Hudson Strait, and there is a smaller connecon to the Arcc Ocean via Fury and Hecla Strait. The HB complex is shallow except for Hudson Strait. The seafloor of Map: The Hudson Bay Hudson Bay is comprised of two Complex LME. saucer-shaped basins separated by a ridge-like feature that extends from Source: AMSAIIC Report the south shore and rises to a depth of < 40 m at the Midbay Bank. A broad coastal shelf extends to 80 m depth offshore the coasts of Québec (20-50 km), Manitoba and Kivalliq (50-70 km), and Ontario and the northern islands (100 km). The bo`om slopes gradually from the shelf across the HB complex from northwest to southeast, to a smooth sea floor with an average depth of 250 beginning in early October in northern Foxe Basin, m. Hudson Strait deepens progressively to 1,000 m in spreading into northern Hudson Bay and Hudson the east, north of Ungava Bay, and then rises to a sill Strait by mid-October, and finally into southern less than 400 m deep that separates the HB complex James Bay and eastern Hudson Strait by early from the Labrador Sea. december. The extent and thickness of the ice increase rapidly during November and december, Hudson Bay is essen=ally ice-covered in winter and with maximum coverage in late April or early May. ice-free in summer. Most ice forms locally but a small Maximum ice thickness varies but generally amount of mul=-year ice enters via Fury and Hecla increases from south to north, ranging from about 1 Strait. Mul=-year ice is rare in Hudson Bay and "2 m in southern James Bay to 2 m in northern Foxe absent from James Bay. New ice forms progressively Basin. ! MARINE MAMMALS AtlanNc walrus and ringed, bearded, and harbour Canadian ArcNc area, with a large fracNon of them seals inhabit the waters of the HB complex year- occurring in the Hudson Bay Complex. round, while polar bears and ArcNc foxes frequent coastal areas in summer and ice habitats during Harbour seal is a coastal and insular seal with wide other seasons. Harp and hooded seals and at least six distribuNon in temperate, boreal and sub-ArcNc areas species of whales including beluga, bowhead, of both the North AtlanNc and North Pacific. Small narwhal, killer, minke, and humpback whales are resident populaNons of harbour seals occur along the typically seasonal visitors to the region, although the coasts of Hudson Bay and James Bay. They are found first three species do overwinter in Hudson Strait and in areas where currents maintain open water year- someNmes in leads and polynyas elsewhere. The round, typically in freshwater or estuarine rapids, quality, extent and duraNon of the sea ice cover are small coastal polynyas, or at the ice edge. Harbour vitally important determinants of their seasonal seals occur in many of the larger river systems of distribuNons, movements, reproducNve success, and southern Hudson Bay including Thleiwaza, Seal, survival. Churchill, and Nelson. There is lible informaNon on numbers of harbour seals and their populaNon size in The ringed seal is the most common and abundant Hudson Bay has not been esNmated. species of seal in the HB complex, where it is resident year-round. Ringed seals occur in water of virtually Harp seal is a North AtlanNc species that occurs with any depth and their distribuNons likely are driven three stocks: Northwest AtlanNc, Greenland Sea/ primarily by availability of predator-relief habitat, West Ice, and Barents Sea/White Sea stocks. Harp food availability and ice condiNons. Ringed seals in seals from the large Northwest AtlanNc stock are Hudson Bay are relaNvely small with an asymptoNc seasonal visitors to the HB complex which is part of length of about 1.2 m and a weight of about 50 kg. the summer feeding range for these seals. Migratory Ringed seals are adaptable in their feeding habits and harp seals move into Hudson Strait where they are eat a variety of pelagic, nectonic, and benthic common before the shore ice leaves in spring, rare in invertebrates and fishes--parNcularly the amphipod summer, and common again in autumn acer the Themisto libellula, the mysid Mysis oculata, polar shore ice forms. Some seals move further west into cod, and sculpins. Sandlance appears to be an northern Hudson Bay and some may also move north important food item for ringed seals in Hudson Bay in Foxe Basin. The fracNon of the stock of harp seals while polar cod contribute less to the seal diet here that move into Hudson Strait and Hudson Bay is not than in many other ArcNc regions. The total number known but has been considered to be small. The of ringed seals in the Hudson Bay Complex is not Northwest AtlanNc stock of harp seals has been (well) known. Smith (1975) esNmated a populaNon of increasing from a low of about 2 million in the early about 0.5 million ringed seals in Hudson and James 1970s to around 7-8 million in 2010. Associated with Bays. this increase they are possibly re-occupying the former range within the HB complex. Bearded seal is a much larger species than ringed seal, weighing 250-300 kg and measuring 2-2.5 m in Hooded seal is a North AtlanNc species found with length. The species has a circumpolar distribuNon in two main populaNons in the northwestern and ice-covered waters and occurs with two recognized northeastern Atlanc. Seals of the western subspecies for the Atlanc and Pacific sectors. populaNon are seasonal visitors to the HB complex. Bearded seals of the AtlanNc subspecies are patchily The Northwest AtlanNc populaNon has three distributed in the HB complex, typically at low whelping areas on pack ice in the ‘Front’ area (off densiNes relaNve to ringed seals, in areas of moving southern Labrador and northern Newfoundland), sea ice and open water in depths of less than Gulf of St. Lawrence, and Davis Strait. Some hooded 150-200 m, especially areas in the 25-50 m depth seals migrate via Hudson Strait into northern Foxe range. Bearded seals are found throughout the Basin in July and return south in September. It is not Hudson Bay Complex with the largest numbers known if these are seals that arrive from the molNng indicated to occur in Foxe Basin, Hudson Strait and area in the Denmark Strait or if they molt on the northern and eastern Hudson Bay. There are no good Canadian side before they move into Foxe Basin. esNmates of populaNon size of bearded seals in the Hooded seals are uncommon in Hudson Bay and Hudson Bay Complex. Cleator (1996) suggested a James Bay. minimum of 190 thousand bearded seals for the total "3 ! AtlanDc walrus were once widely distributed in the belugas from any of the stocks. The Western and Canadian ArcNc from the northern ScoNan Shelf to Eastern Hudson Bay belugas are on average smaller the central High ArcNc including Hudson Bay. Since than those of the High ArcNc and Cumberland Sound the 1920s there has been a general shic in walrus populaNons. This may be a reflecNon of the distribuNon in the HB complex away from human difference in diets between the Hudson Bay communiNes to areas that are less accessible. Three populaNons and the more northern populaNons of AtlanNc walrus populaNons or stocks have been beluga. idenNfied in the HB complex: Foxe Basin, Southern and Eastern Hudson Bay, and Northern Hudson Bay- Narwhals in Hudson Bay are from the Hudson Bay Davis Strait. The Foxe Basin stock is distributed year- populaNon which is considered to be separate from round in the relaNvely shallow waters of northern the Baffin Bay metapopulaNon.