The role of interannual environmental variations in the geographic range of spawning and feeding concentrations of redfish Sebastes mentella in the Irminger Sea

Abstract

The Irminger Sea is occupied by the most abundant population of the redfish, Sebastes mentella, in the North Atlantic. Results of Russian and international surveys of redfish in the Irminger Sea between 1982 and 2003 are summarized here. Interannual variations in redfish spatial distribution and oceanographic conditions are also analysed. Distribution patterns of spawning and feeding concentrations of redfish are established, and the role of oceanographic factors in the formation of concentrations and in the migrations of redfish are shown. The habitat of the mature redfish population in pelagic waters is confined within the Sub-polar cyclonic Gyre. Redfish spawning grounds extend along the western slope of the Reykjanes Ridge in the areas of intensive rise of intermediate waters. Seasonal variation in water temperature above the ridge slopes is one of the factors causing feeding redfish to migrate westwards, to the central area of the Sub-polar Gyre. Atlantic Water advection, intensified by the Irminger Sea, and water temperature increase in the upper 200-m layer in the second half of the 1990s produced a considerable shift of commercial concentrations of feeding redfish from their usual grounds westwards, to the NAFO Regulatory area.

Three‐dimensional post‐glacial expansion and diversification of an exploited oceanic fish

“…Their distributions are found within close proximity of bathymetric features (see Fig. ) along the west of the Reykjanes Ridge and the Faroe‐Shetland Ridge known for complex oceanic conditions at depth (Pedchenko ; Olsen et al . ).…”

The Dynamics of the North Atlantic Subpolar Gyre Introduces Predictability to the Breeding Success of Kittiwakes

“…Having circumvented the Iceland Basin, the kittiwakes settle in a region between 29 • and 36 • W (Bogdanova et al, 2011), which is on and just west of the Reykjanes Ridge (Figure 1). This is the location of the subarctic front, which is one of the most productive regions in the North Atlantic (Pedchenko, 2005;Hátún et al, 2016). The metrics presented by Hátún et al (2016) connect the mixed layer depth and the C. finmarchicus abundance in the Irminger Sea, lateral shifts of the subarctic front, and the zooplankton abundance on the south Iceland shelf.…”

“…The Faroe kittiwake breeding success is sampled at site "K," and the Icelandic zooplankton record is sampled at site "Z." 29 • and 36 • W (Bogdanova et al, 2011), which roughly coincides with the highly productive subarctic front west of the Reykjanes Ridge (Pedchenko, 2005;Hátún et al, 2016).…”

Monitoring beaked redfish (Sebastes mentella) in the North Atlantic, current challenges and future prospects

“…During the early 1990s the circulation of the gyre was intense, but declined substantially after 1995 leading to a rapid warming and increased salinity (Hátún et al 2009). As suggested by Pedchenko (2005), it is possible that the SPG influences the upper and lower water masses in the Irminger Sea differently, thereby explaining the different horizontal distribution of S. mentella in the shallow and the deep Irminger Sea.…”

“…The physical oceanography in this region is variable (Hátún et al 2009) and is dominated by the dynamics of the North Atlantic Sub-Polar Gyre (SPG), a large counter-clock rotating body of relatively cold and low-saline subarctic water in the central northern North Atlantic. The distribution of S. mentella is confined within the SPG (Pedchenko 2005). During the early 1990s the circulation of the gyre was intense, but declined substantially after 1995 leading to a rapid warming and increased salinity (Hátún et al 2009).…”