Greenland whales and walruses in the Svalbard food web before and after exploitation

Between 1600 and 1900 two numerous and ecologically important large marine mammals were extirpated in the Svalbard archipelago. These were the pelagic-feeding Greenland whale (Balaena mysticetus) and the benthic-feeding walrus (Odobaenus rosmarus rosmarus), the initial stocks of which prior to exploitation are estimated to have numbered approximately 46 000 and 25 000 animals respectively. Their annual food consumption at that time is estimated to have been some 4 million tons of plankton and 0.4 million tons of benthic organisms. Assuming that the primary and secondary production of the shelf/coastal ecosystem in the 16th century (before the peak of the Little Ice Age) was similar to that of the present day, the authors have concluded that a major shift in the food web must have occurred after the Greenland whales and walruses were eliminated. Planktonivorous seabirds and polar cod (Boreogadus saida) very probably took advantage of the extirpation of the Greenland whales, while eiders (Somateria mollissima) and bearded seals (Erignathus barbatus) benefited from the walrus's extinction. In turn, the increased amount of pelagic fish provided food for piscivorous alcids and gulls, and may have given rise to the huge present-day seabird colonies on Svalbard

Greenland whales and walruses in the Svalbard food web before and after exploitation

Between 1600 and 1900 two numerous and ecologically important large marine mammals were extirpated in the Svalbard archipelago. These were the pelagic-feeding Greenland whale (Balaena mysticetus) and the benthic-feeding walrus (Odobaenus rosmarus rosmarus), the initial stocks of which prior to exploitation are estimated to have numbered approximately 46 000 and 25 000 animals respectively. Their annual food consumption at that time is estimated to have been some 4 million tons of plankton and 0.4 million tons of benthic organisms. Assuming that the primary and secondary production of the shelf/coastal ecosystem in the 16th century (before the peak of the Little Ice Age) was similar to that of the present day, the authors have concluded that a major shift in the food web must have occurred after the Greenland whales and walruses were eliminated. Planktonivorous seabirds and polar cod (Boreogadus saida) very probably took advantage of the extirpation of the Greenland whales, while eiders (Somateria mollissima) and bearded seals (Erignathus barbatus) benefited from the walrus's extinction. In turn, the increased amount of pelagic fish provided food for piscivorous alcids and gulls, and may have given rise to the huge present-day seabird colonies on Svalbard

Chances for Arctic Survival: Greely's Expedition Revisited

Greely's historic starvation camp of 1883-84 was revisited from April to June 1998. Our study revealed that the "sea fleas" reported to be the salvation of the expedition survivors were lysianassoid crustaceans Onisimus edwardsi. Expedition diaries reveal that the seven survivors of the 25-member expedition accumulated a huge energy deficit from October 1883 to June 1894. We estimate that their food supply (ship's rations, sparse game, and over 500 kg of carrion-feeding crustaceans collected in spring 1884) added up to about 4.8 million kcal. The minimal energy requirement of the group (5725 man/days and 1200 kcal/person/day) was 6.8 million kcal. The additional 2.0 million kcal might have been obtained from the bodies of victims. Without cannibalism, it seems unlikely that anyone, having attained an individual energy deficit of over 86000 kcal before the rescue in June 1894, could have survived.D'avril à juin 1998, on est retournés sur le site du campement de A. W. Greely qui, en 1883-1884, connut une famine historique. Notre étude révèle que les "puces de mer" auxquelles les survivants de l'expédition auraient dû leur salut étaient en fait des crustacés lysianassoïdes Onisimus edwardsi. Les journaux de l'expédition révèlent que, d'octobre 1883 à juin 1884, les 7 survivants de l'expédition, qui comprenait au départ 25 individus, accumulèrent un énorme déficit énergétique. On estime que leurs vivres (rations de marin, quelque gibier et plus de 500 kg de crustacés nécrophages ramassés au printemps de 1884) représentaient un maximum d'environ 4,8 millions de kcal. Les besoins énergétiques minimaux du groupe (5725 jours-personnes et 1200 kcal/personne/jour) étaient de 6,8 millions de kcal. Les 2,0 millions de kcal manquant auraient pu provenir des corps des victimes. Il semble en effet improbable que quelqu'un souffrant d'un déficit énergétique individuel supérieur à 86 000 kcal avant le sauvetage de juin 1884 ait pu survivre sans pratiquer le cannibalisme

Winter in a Svalbard Fiord Ecosystem

Data pertaining to the characteristics of an arctic fiord in winter were collected at the Polish Arctic Station situated in Hornsund at 77 degrees N, 15 degrees E on Svalbard. Winter in the fiord was defined in terms of climate (November-May), hydrology (January-March) and biology (November-March). The characteristic phenomena of winter in the fiord include a winter drop in the yearly biomass maximum to 0.1% for phytoplankton and 10% for zooplankton; a slowing of the growth rate among pelagic dominants such as Pseudocalanus elongatus and Calanus finmarchicus, as well as among the hyperbenthic dominants Onisimus littoralis and Mysis oculata; and heterotrophy or maintenance of metabolism among living phytoplankton cells found in the middle of the polar night in densities of 10-50 cells/L. Since the life cycles of invertebrates are highly seasonal, no winter breeders were observed and 90% of the examined species were breeding according to a K strategy. Migration takes place among all seabirds in the area, but about 1% of the eiders, fulmars and kittiwakes overwinter, feeding in the open water of polynyas and crevices in the fast ice.Key words: Arctic, winter ecology, fiord ecosystem, Svalbard, Hornsund fiordMots clés: Arctique, écologie de l’hiver, écosystème de fjord, Svalbard, fjord Hornsun

Meiofauna as descriptor of tourism-induced changes at sandy beaches

Tourism has long been considered as a ‘clean industry’ with almost no negative effects on the environment. This study demonstrated, in two different coastal systems (Mediterranean and Baltic), that tourism related activities are particularly affecting the sandy beach meio- and nematofauna in the upper beach zone, the specific ecotone in which many meiofauna species from both the marine and the terrestrial environment congregate. Tourist upper beaches are characterized by a lower % total organic matter (%TOM), lower densities, lower diversities (absence of Insecta, Harpacticoida, Oligochaeta, terrestrial nematodes and marine Ironidae nematodes) and higher community stress compared to nearby non-tourist locations. The %TOM was found to be the single most important factor for the observed differences in meiofauna assemblage structure at tourist versus non-tourist beaches in both the Mediterranean and the Baltic region. The free-living nematode assemblages from tourist upper zones depart significantly from expectations based on random selections from the regional nematode species pool. Furthermore upper zone assemblages are characterised by a low species diversity consisting of taxonomically closely related nematode species with r-strategist features. Generally, faunal differences between tourist and non-tourist beaches are decreasing towards the lower beach zones

Diet of Ringed Seals (Phoca Hispida) in a Fjord of West Svalbard

Stomachs of 134 ringed seals from West Svalbard (Kongsfjorden) and East Svalbard (drift ice) were examined. Twenty-four prey taxa were found. The most important items were arctic cod (Boreogadus saida), shrimp (Pandalus borealis), krill (Thysanoessa inermis) and the amphipod Themisto libellula. In spring young redfish (Sebastes sp.) was an important food item; in summer seals fed on dense aggregations of krill in front of glaciers. Mysids, amphipod crustaceans and small size classes of coastal fish species were abundant in Kongsfjorden, but seals take them as secondary food items only.Key words: ringed seals, Phoca hispida, arctic food web, fjord ecology, Svalbard, prey taxaOn a étudié l'estomac de 134 phoques annelés du Svalbard occidental (Kongsfjorden) et du Svalbard oriental (glace de dérive). On a recensé 24 espèces-proies. Les plus importantes étaient la morue arctique (Boreogadus saida), la crevette (Pandalus borealis), le krill (Thysanoessa inermis) et l'amphipode Themisto libellula. Au printemps, la sébaste juvénile (sp. Sebastes) représentait une importante source alimentaire; en été, les phoques se nourrissaient du krill trouvé en forte concentration au pied des glaciers. Dans le Kongsfjorden, il y avait en abondance des mysis, des amphipodes et des espèces de poissons côtiers de petite taille, mais qui ne constituaient pour les phoques qu'une source alimentaire secondaire.Mots clés : phoques annelés, Phoca hispida, réseau trophique de l'Arctique, écologie de fjord, Svalbard, espèce-proi

Greenland whales and walruses in the Svalbard food web before and after exploitation

Between 1600 and 1900 two numerous and ecologically important large marine mammals were extirpated in the Svalbard archipelago. These were the pelagic-feeding Greenland whale (Balaena mysticetus) and the benthic-feeding walrus (Odobaenus rosmarus rosmarus), the initial stocks of which prior to exploitation are estimated to have numbered approximately 46 000 and 25 000 animals respectively. Their annual food consumption at that time is estimated to have been some 4 million tons of plankton and 0.4 million tons of benthic organisms. Assuming that the primary and secondary production of the shelf/coastal ecosystem in the 16th century (before the peak of the Little Ice Age) was similar to that of the present day, the authors have concluded that a major shift in the food web must have occurred after the Greenland whales and walruses were eliminated. Planktonivorous seabirds and polar cod (Boreogadus saida) very probably took advantage of the extirpation of the Greenland whales, while eiders (Somateria mollissima) and bearded seals (Erignathus barbatus) benefited from the walrus's extinction. In turn, the increased amount of pelagic fish provided food for piscivorous alcids and gulls, and may have given rise to the huge present-day seabird colonies on Svalbard