West Coast Of Greenland Research Articles

Plasma flow during the brightening of proton aurora in the cusp

On the basis of simultaneous observations from the Super Dual Auroral Radar Network (SuperDARN), the far ultraviolet instrument on the IMAGE spacecraft, and a magnetometer installed on the east coast of Greenland, we present the characteristics of plasma flow during a westward moving proton aurora in the cusp, observed on 28 July 2000. Data with a time resolution of 12 and 25 s from SuperDARN at Þykkvibær, Iceland, show that the flow having a poleward component, which was accompanied by a quick equatorward expansion of the flow region, occurred in the early stages (approximately 1.5 min) of the brightening. Data from the magnetometer from a ground station on the Greenland east coast, which is located a few hundred kilometers west of the radar's field of view, show perturbations that are consistent with equatorward flow overhead, coincident with the expansion. The presence of flow vectors in opposite directions suggests that vortical flow was present during the proton aurora. Evidence supporting the suggested flow pattern has been found in an event recorded by the Greenland west coast magnetometer chain and in a cusp pass of the DE 2 spacecraft in the literature. We attribute the moving proton aurora to the traveling bulge at the polar cap boundary, which is the footprint of a flux transfer event, and imply that the preexisting vortical flow may be intensified when it becomes inflow to the bulge.

Coastal tides in West Greenland derived from tide gauge records

Based on pressure tide-gauge observations, sea-level records are derived for ten sites along the coast of West Greenland. The ocean tidal signal is extracted by a harmonic tidal analysis. The accuracy of the determined tidal constants is discussed in detail. The tides account for 85% of the observed sea-level standard deviation. The tide gauge records reveal significant shallow-water tidal effects, in particular compound and overtide amplitudes reaching 5 cm. The propagation of the tidal waves into the fjords depends strongly on local conditions and is in some cases accompanied by an amplification of the tidal amplitudes. The observed tidal signals are compared to the predictions of the global ocean tide model FES2004. At the outer coast, a good agreement is found. Inside the fjords, however, the model performs worse and tide gauge observations may still be indispensable when accurate tidal signals are required.

Catch history and status of the harbour seal (<i>Phoca vitulina</i>) in Greenland

The number of harbour seals (Phoca vitulina) in West Greenland declined rapidly after the 1950s and the seals have now abandoned their traditional haulout locations along the Greenland west coast. However, in recent years, a previously undetected group of about 60-100 harbour seals has been observed approximately 80 km upstream in a large river, and some traditional hauloutlocations are still in use near the south-eastern tip of Greenland. A small number of harbour seals is caught annually far from any of these locations, indicating that other groups might live unnoticed. Catch statistics provide the best evidence of the presence and locations of these remnant harbour seals. Therefore efforts were made to validate the recent catch statistics and to describe the catch history for the past 60 years. The catch statistics were also used to estimate plausibleranges of past and present numbers of harbour seals based on the assumption that hunting has caused the observed decline. The total number of harbour seals in Greenland according to these estimates was about 3,000 in 1950 and fewer than 1,000 in 2007. The number of harbour seals caught in the southernmost part of Greenland has, unlike in the rest of Greenland, increased significantly in some of the recent years. This change seems to be related to changes in the amount of drift ice. Drift ice reduces the frequency of contact between hunters and harbour seals in South Greenland and above normal quantities of drift ice from the mid 1960s to the mid 1980s probably allowed these seals to increase in numbers. Record low inflow of drift ice in some of the recent years, however, has resulted in record high catches, which likely have reduced the seals again. The remaining harbour seals in Greenland are few and without protection these sealsare potentially in danger of extinction.

Short-term impacts of enhanced Greenland freshwater fluxes in an eddy-permitting ocean model

Abstract. In a sensitivity experiment, an eddy-permitting ocean general circulation model is forced with realistic freshwater fluxes from the Greenland Ice Sheet, averaged for the period 1991–2000. The fluxes are obtained with a mass balance model for the ice sheet, forced with the ERA-40 reanalysis dataset. The freshwater flux is distributed around Greenland as an additional term in prescribed runoff, representing seasonal melting of the ice sheet and a fixed year-round iceberg calving flux, for 8.5 model years. By adding Greenland freshwater fluxes with realistic geographical distribution and seasonality, the experiment is designed to investigate the oceanic response to a sudden and spatially/temporally uniform amplification of ice sheet melting and discharge, rather than localized or gradual changes in freshwater flux. The impacts on regional hydrography and circulation are investigated by comparing the sensitivity experiment to a control experiment, without additional fluxes. By the end of the sensitivity experiment, the majority of additional fresh water has accumulated in Baffin Bay, and only a small fraction has reached the interior of the Labrador Sea, where winter mixed layer depth is sensitive to small changes in salinity. As a consequence, the impact on large-scale circulation is very slight. An indirect impact of strong freshening off the west coast of Greenland is a small anti-cyclonic component to the circulation around Greenland, which opposes the wind-driven cyclonic circulation and reduces net southward flow through the Canadian Archipelago by ~10%. Implications for the post-2000 acceleration of Greenland mass loss are discussed.

Impacts of "Storis" on the Thermohaline Stratification off West Greenland

This paper examines the variability in the hydrographic conditions in the waters off West Greenland with a focus on the influence of the Polar Water off East Greenland and its associated sea ice or “Storis”. During the mid-1970s, mid-1980s and early-1990s, maxima of Polar Water were observed in the upper water layers off Fyllas Bank, West Greenland. At a station located on the offshore bank slope in about 900 m of water, the upper 75 m of the water column are primarily influenced by the Polar Water and the “Storis”. There, monthly mean temperatures are maximum and salinities a minimum during August–September. In years of larger than usual amounts of “Storis”, cold diluted surface waters appear along the west coast of Greenland. Observations of sea surface temperature anomalies off Fyllas Bank during July indicate strong warming from 1989 to 2008, going from what appears to be the coldest year to close to the warmest. Warm anomalies were actually re-established in 1996. Warmer-than-normal sub-surface conditions peaked in 2003, a year with no “Storis”. From 2002 onwards, a phenomenon is observed which seems to indicate a new structure in the distribution of SST anomalies: a band of colder-than-normal waters on the shelves off East and West Greenland. It is assumed that the continuous warming has led to massive sea ice melt off East Greenland, and the ice drifts with the East Greenland Current along the shelves off East and West Greenland, strongly influencing the temperature and salinity characteristics of the surface waters.

Pattern and causes of a temperature-dependent gradient of size at terminal moult in snow crab (Chionoecetes opilio) along West Greenland

Geographic variation in size of male and female snow crabs (Chionoecetes opilio) was investigated along the west coast of Greenland to test the hypothesis that size at terminal molt (=adulthood) is temperature dependent. A total of 81,490 snow crabs were collected in small-mesh traps in Disko Bay (68–69°N) and six sites near Sisimiut (66–67°N) in May and June from 2000 to 2005. Average bottom temperature over the study period ranged from −0.8 to 3.2°C across the sampling sites. Mean carapace width was positively correlated with temperature in both sexes, a pattern often described as a converse Jame’s cline. We infer that temperature per se is the causative factor and discount season length, food availability or density as ultimate causes of the cline. Temperature effects on body size of crabs apparently result from a change in the number of instars before terminal molt. This interpretation is supported by size frequency analysis showing that in general crabs were larger at instar in a colder than in a warmer site. We briefly discuss the implications of our findings for population reproductive potential and the effectiveness of a fixed legal size limit in protecting some adult males from exploitation at different temperature regimes.

Probabilistic-based genetic assignment model: assignments to subcontinent of origin of the West Greenland Atlantic salmon harvest

AbstractSheehan, T. F., Legault, C. M., King, T. L., and Spidle, A. P. 2010. Probabilistic-based genetic assignment model: assignments to subcontinent of origin of the West Greenland Atlantic salmon harvest. – ICES Journal of Marine Science, 67: 537–550. A multistock Atlantic salmon (Salmo salar) fishery operates off the coast of West Greenland and harvests fish of North American and European origin. Annual landings peaked in 1971 at 2700 t, but declined to 22 t in 2003. Biological data are collected to characterize the catch and its stock composition. Multilocus genotypes, generated via microsatellite DNA analysis, are used to derive statistics on continent of origin and less accurate finer-scale assignments. We developed a probabilistic-based genetic assignment (PGA) model to estimate the contribution of salmon from individual North American rivers in the 2000–2003 West Greenland catch. Uncertainty associated with finer-scale assignments is addressed by incorporating estimated misclassification rates and by reporting results as distributions generated via Monte Carlo resampling. US-origin fish represented ∼1% (by number) of the salmon harvested at West Greenland during the years 2000–2003. The resulting loss of spawners to this stock complex was approximately half the estimated adult returns in 2001, but was below 4% in the other 3 years. This is the first attempt to partition the US component of the West Greenland mixed-stock fishery to its finer parts. The approach can be used to identify the effects of fishing on individual stocks within any multistock complex where genetic samples of known origin are available.

Temperature effects on growth of juvenile Greenland halibut ( Reinhardtius hippoglossoides Walbaum) in West Greenland waters

The relationship between temperature and growth of juvenile Greenland halibut ( Reinhardtius hippoglossoides Walbaum) from 1993 to 2003 was studied in West Greenland offshore waters. In 1993–1996 the average temperature was 2.0 °C but it increased to 3.4 °C in 1997 and remained at this level for the rest of the study period. Concurrent with the temperature increase, mean total length of 1-year-old Greenland halibut increased significantly in all areas and depth strata. For example, mean length of 1-year-old halibut in Disko Bay at depths from 201 to 400 m increased from about 13 cm to 15 cm when temperature rose from 1.5 °C to 3 °C. On average the mean length of the 1-year-old Greenland halibut increased 1.6 cm °C − 1 and, similarly, the increase in length from 1 to 2 years old increased on average 1.5 cm °C − 1 . There was no significant correlation between temperature and density of the 1- and 2-year-old Greenland halibut, but the instantaneous mortality rate from 1 to 2 years old was positively correlated with temperature ( r = 0.71, n = 10, P = 0.021), and with density of 1-year-old fish ( r = 0.81, n = 10, P = 0.005). Higher mortalities were found in the warmer years. Future increase in temperature along the west coast of Greenland is likely to result in enhanced growth of juvenile Greenland halibut. Whether this leads to increased recruitment is uncertain as density-dependent mortality of the settled juvenile Greenland halibut appears to counteract the positive effects of enhanced growth.

An assessment of a Greenland lee cyclone during the Greenland Flow Distortion experiment: An observational approach

AbstractOn 3 March 2007 between 0920 and 1545 UTC, the mesoscale structure of a mature lee cyclone southeast of Greenland was successfully captured during a flight with a research aircraft during the Greenland Flow Distortion experiment (GFDex). The cyclone was accompanied by hazardous weather conditions such as extensive icing and low‐level wind speeds exceeding 34 m s−1. Calculations based on atmospheric soundings from Egedesminde on the west coast of Greenland indicate that conditions were favourable for flow splitting and hence cyclogenesis in the lee of Greenland during the formation of the cyclone. PV inversion carried out on an upper‐level southward‐moving potential vorticity (PV) anomaly indicates that upper‐level forcing as well as orographic forcing had an important role in the cyclone development. The frontal seclusion of the cyclone's warm core was consistent with both the Norwegian cyclone model and Shapiro and Keyser's model. However, it was not possible to match this cyclone precisely with any of these models, which is probably a consequence of the strong influence from Greenland on the cyclone development. In situ measurements showing a combination of warm dry air with relatively high ozone concentrations in the centre of the cyclone together with trajectory calculations indicate that this air had experienced considerable descent, probably induced by Greenland's orography. The observations documented the cyclone's mesoscale structure, and clearly revealed a deep tropopause fold. This tropopause fold is a manifestation of the forcing on the cyclone from the upper‐level PV anomaly. Copyright © 2009 Royal Meteorological Society

Hepatitis D outbreak among children in a hepatitis B hyper-endemic settlement in Greenland

Hepatitis B virus (HBV) infection is endemic in Greenland with 5-10% of the population being HBsAg-positive (chronic carriers). Surprisingly, despite of the high prevalence of HBV infection, acute and chronic hepatitis B, liver cirrhosis and primary hepatocellular carcinoma appear much less frequently than expected. The reasons for the low frequencies are unknown, but as a consequence implementation of a childhood HBV vaccination programme, though debated for years, has never been instituted. We describe an outbreak of hepatitis D (HDV) infection among children in a hepatitis B hyper-endemic settlement of 133 inhabitants on the west coast of Greenland. In 2006 a total of 27% of the inhabitants were HBsAg-positive (chronic carriers) and 83% were HBcAb-positive (previously exposed). Forty-six percent of the HBsAg-positive persons were below 20 years of age. On follow-up 1 year later a total of 68% of the HBsAg-positive persons were HDV-IgG positive. Five children, who were HBsAg-positive in 2006, had HDV-seroconverted from 2006 to 2007, indicating a HDV-super-infection. Most of the HDV-IgG positive children had markedly elevated liver enzymes. In the multivariate analysis, among the HBV and HDV markers, presence of HDV-IgG was most strongly associated with elevation of liver enzymes. In conclusion, the HBV-HDV super-infection and presumed HDV outbreak in this settlement challenges the notion that HBV infection may not be as harmless in Greenland as previously anticipated. The findings strongly suggest that HBV vaccination should be included in the child-immunization program in Greenland.

Nutrition classics. The Lancet, Vol. I for 1971: Plasma lipid and lipoprotein pattern in Greenlandic West-Coast Eskimos. By H.O. Bang, J. Dyerberg, Aase Brøndum Nielsen.

Summary: The plasma-lipid pattern, including quantitative lipoprotein electrophoresis, was examined in 130 Eskimos (69 females, 61 males)—hunters and/or fishermen, and their wives—in the northern part of the west coast of Greenland, and consuming a predominantly meat diet rich in polyunsaturated fatty acids. Most types of lipid were decreased, compared with Danish controls and Eskimos living in Denmark. The most remarkable finding was much lower levels of pre-β-lipoprotein and consequently of plasma-triglycerides in Greenlandic Eskimos than in Danish controls. These findings may explain the very low incidence of ischaemic heart-disease and the complete absence of diabetes mellitus in Greenlandic Eskimos.

Survey of the Steam Yacht Fox at Qeqertarsuaq (Disko Island, Greenland, 20th Century)

The remains of the steam yacht Fox, abandoned after grounding in 1912, lie in a shallow cove in the harbor of Qeqertarsuaq (Gødhavn) on Disko Island off the west coast of Greenland. Known for its role in an expedition led by Francis Leopold McClintock to determine the fate of an earlier expedition in search of the Northwest Passage commanded by Captain Sir John Franklin, the Fox subsequently passed into Danish ownership and worked the west coast of Greenland until its abandonment. In August 2003, an underwater survey and archaeological reconnaissance documented the wreck. The survival of substantial hull remains on the shores of a small bay covered by ice each year demonstrates that a “common sense” assumption of ice destruction of Arctic shipwrecks in shallow water environments is not justified, and that archaeological integrity can be preserved even after a wreck is flattened by ice impact.

Nuussuarmiut – hunting families on the big headland. Demography, subsistence and material culture in Nuussuaq, Upernavik, Northwest Greenland

This description of a small hunting community, the settlement of Nuussuaq, Kraulshavn, in the northern Upernavik district on the west coast of Greenland, is based on fieldwork carried out in the period from 1966 to 1968. The main emphasis is on events during the course of the year from November 1967 to October 1968. During such a ‘case study’, when so many things naturally happen in the course of the year, subjective choices are necessarily made with regard to what to emphasise and pass on. The Norwegian anthropologist Frederik Barth said that “what we empirically observe is not ‘customs’ but ‘cases’ of human behaviour, it seems to me that we cannot escape the concept of choice in our analyses” (Barth 1966:1). Daily life in the settlement itself and out on the hunting grounds is followed day by day for the year in question. However, when processing the information collected in the study year, two questions quickly presented themselves: How did these hunting families manage in the past and what has happened to them in the subsequent 30 years up to the present day? A good impression of their life in the settlements back into the 18th and 19th centuries can be provided by the archaeological evidence. The time from the establishment of the settlement of Nuussuaq in 1923 until the study period and the subsequent period can, on the other hand, be traced through church registers, the official population and hunting statistics, written and oral information and photographs. A long-term ethnographic study presents the opportunity to reveal the continuity in society and to demonstrate changes. With a few exceptions the latter have not been of such radical importance for the inhabitants of these northern areas as has been the case in the majority of other places in Greenland and the rest of the Arctic. One would expect that the influences from north and south, from the administration, introduction of home rule, changing ecological circumstances, drastic reduction in the price of furs as a consequence of the anti-sealskin campaign in Europe and the USA in the late 1970s etc. would at times have prompted many families to give up. That they would have accepted the offer from the authorities to be relocated south to the promised new and better housing and with a change in occupation as a consequence. But the collected evidence demonstrates a surprising stability. The hunting families have retained a great part of their traditional way of life and the majority of their traditional tools. This is not due to conservatism but because experience has shown them that these are the most efficient under the given conditions. As will be apparent later, new tools and a number of other items have been introduced in recent times, but these have only been adopted when they proved to be more efficient than those already in use. In a large number of cases they are used in conjunction with the traditional tools. The fact that, on the periphery of modern Greenlandic society, there are still families who continue to give the highest priority to this way of life is promising as it shows that the traditional occupation of hunter is not about to die out.

Diatoms reveal complex spatial and temporal patterns of recent limnological change in West Greenland

Diatoms in sediment cores were analysed across a range of stratigraphic resolutions along a transect of 23 lakes spanning the ice-free margin of the west coast of Greenland (~67°N), to explore spatial and temporal patterns of recent (last ~150 years) environmental change in the region. These records display heterogeneous lake development trajectories over the last several centuries. Estimates of species composition turnover (beta-diversity) since 1850 AD are among the lowest for lakes in the Arctic, and are comparable to “unimpacted” reference lakes from temperate regions. Most of the change that occurred in West Greenland lakes pre-dates potential industrial anthropogenic effects, while post-1850 change is well within the natural range of variability for these systems. Nonetheless, a spatial pattern in core “top–bottom” changes is apparent across the transect: lakes in the arid interior of the region, adjacent to the ice sheet, and those with higher pH, register greater change than those in the more maritime climate of the coast. This suggests that climate plays an indirect role in the recent development of these lakes, and that recent anthropogenic forcing has not yet exceeded major ecological thresholds in this region.

Full Circle

Greenland, and more specifically the present-day south west coastal district, is that exact spot on the world map where humankind completed its conquest of the Earth. As Norsemen coming over the Atlantic from Iceland and Norway encountered first North-American natives in present-day Labrador around year 1000, and about 150 years later the Inuit coming in from Baffin, slowly occupying the Greenland west coast, humankind had finally encircled the globe, unaware of the extraordinary aspect of the situation. The first few encounters in Labrador were violent, but later, cohabitation in South West Greenland had a mainly peaceful character. Present-day Narsaq district is the precise area where archeology gives witness to peaceful cohabitation between Inuit and Norsemen in the first half of the 15th century.

Extreme Snowmelt in Northern Greenland During Summer 2008

Extreme snowmelt occurred during summer 2008 over the northern part of the Greenland ice sheet, according to the analysis of microwave data recorded by the Special Sensor Microwave Imager (SSM/I) on board the F13 satellite of the U.S. Defense Meteorological Satellite Program (DMSP). New records of the number of melting days were also observed over large portions of the same areas (letters A and B in Figure 1).Anomalies of the 2008 number of melting days (i.e., the difference between the 2008 number of melting days and the 1979–2007 average) are reported in Figure 1. In 2008, melting in northern Greenland lasted up to 18 days longer than previous maximum values, and the melting index (i.e., the number of melting days × the area subject to melting) was 3 times greater than the 1979–2007 average, with 1.545×106 square kilometers x days. Also of noticeable value are 2008 anomalies observed along Greenland's west coast, with melting over this area lasting up to 5–10 days longer than the average (letter C in Figure 1).

Acceleration of Jakobshavn Isbræ triggered by warm subsurface ocean waters

Observations over past decades show a sudden switch of Jakobshavn Isbrae—a large outlet glacier feeding a deep-ocean fjord on Greenland’s west coast—from slow thickening to rapid thinning in 1997. This switch is associated with a doubling in glacier velocity. Hydrographic data show a concurrent sudden increase in subsurface ocean temperatures along the entire west coast of Greenland, suggesting that the changes in Jakobshavn Isbrae were triggered by the arrival of relatively warm water originating from the Irminger Sea. Observations over the past decades show a rapid acceleration of several outlet glaciers in Greenland and Antarctica1. One of the largest changes is a sudden switch of Jakobshavn Isbrae, a large outlet glacier feeding a deep-ocean fjord on Greenland’s west coast, from slow thickening to rapid thinning2 in 1997, associated with a doubling in glacier velocity3. Suggested explanations for the speed-up of Jakobshavn Isbrae include increased lubrication of the ice–bedrock interface as more meltwater has drained to the glacier bed during recent warmer summers4 and weakening and break-up of the floating ice tongue that buttressed the glacier5. Here we present hydrographic data that show a sudden increase in subsurface ocean temperature in 1997 along the entire west coast of Greenland, suggesting that the changes in Jakobshavn Isbrae were instead triggered by the arrival of relatively warm water originating from the Irminger Sea near Iceland. We trace these oceanic changes back to changes in the atmospheric circulation in the North Atlantic region. We conclude that the prediction of future rapid dynamic responses of other outlet glaciers to climate change will require an improved understanding of the effect of changes in regional ocean and atmosphere circulation on the delivery of warm subsurface waters to the periphery of the ice sheets.

Eddy Formation near the West Coast of Greenland

Abstract This paper extends A. Bracco and J. Pedlosky’s investigation of the eddy-formation mechanism in the eastern Labrador Sea by including a more realistic depiction of the boundary current. The quasigeostrophic model consists of a meridional, coastally trapped current with three vertical layers. The current configuration and topographic domain are chosen to match, as closely as possible, the observations of the boundary current and the varying topographic slope along the West Greenland coast. The role played by the bottom-intensified component of the boundary current on the formation of the Labrador Sea Irminger Rings is explored. Consistent with the earlier study, a short, localized bottom-trapped wave is responsible for most of the perturbation energy growth. However, for the instability to occur in the three-layer model, the deepest component of the boundary current must be sufficiently strong, highlighting the importance of the near-bottom flow. The model is able to reproduce important features of the observed vortices in the eastern Labrador Sea, including the polarity, radius, rate of formation, and vertical structure. At the time of formation, the eddies have a surface signature as well as a strong circulation at depth, possibly allowing for the transport of both surface and near-bottom water from the boundary current into the interior basin. This work also supports the idea that changes in the current structure could be responsible for the observed interannual variability in the number of Irminger Rings formed.

Exploratory data analysis of the interactions among physics, food web structure, and function in two Arctic polynyas

Polynyas are areas of open water in ice-covered seas, characterized by high biological productivity. The NEW (Northeast Water) and NOW (North Water) polynyas, located off the east and west coasts of Greenland, were extensively sampled in 1993 and 1998, respectively. We used principal component analysis to explore the seasonal covariations among physical, chemical, and ecological characteristics in these polynyas. In both polynyas, the most explanatory eigenvector revealed the expected seasonal development of the bloom (nutrient consumption and biomass increases) associated with declining ice cover, warming, and mixed-layer shallowing. This seasonal pattern, however, was much weaker in NEW than in NOW. No connections between the structure of the food web and recycling processes were apparent in either polynya. The analysis points to much stronger and richer interactions between the mesoplankton (i.e., diatoms–zooplankton) and microbial food webs in NOW than in NEW. The differences between the polynyas may be explained in part by differences in their longevity, with the longer-lived NOW polynya having more time to develop complex trophic interactions. The results also indicate that the connections between food web structure and ecosystem function (i.e., new production versus recycling), at least at the seasonal scale, are weaker than expected.

Population genetic structure of the snow crab (Chionoecetes opilio) at the Northwest Atlantic scale

Marine species with planktonic larval durations of several months (teleplanic larvae) can potentially maintain demographic connectivity across large geographical distances. This perspective has important fundamental and applied implications, notably for the understanding of evolutionary and ecological processes in the marine realm, the implementation of marine protected areas, and fisheries management. Here we present, at the scale of the Northwest Atlantic, a spatial analysis of snow crab (Chionoecetes opilio, Majoidea) population genetic structure, a species that has a planktonic larval phase of 3 to 5 months. Eight microsatellite markers analysed on 847 C. opilio samples from 13 locations revealed an absence of significant genetic structure along the west coast of Greenland and within Atlantic Canada from southern Labrador to Nova Scotia. These results are consistent with a scenario of extensive demographic connectivity among C. opilio populations and have implications for the management of this species, which supports one of the most important Canadian and Greenlandic fisheries in terms of economic value. A genetic break is nevertheless identified between Greenland and Atlantic Canada, showing that genetic structure can develop within seas (the Labrador Sea in this case) despite the occurrence of very long planktonic larval stages.