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    Early Spring Feeding Habits of Bearded Seals (Erignathus Barbatus) in the Central Bering Sea, 1981

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    The diet of bearded seals, Erignathus barbatus, near St. Matthew Island, Bering Sea, was studied during the early spring of 1981. Eighty-six percent of the 78 seals' stomachs examined contained fish. Other prey taxon groups, in decreasing order of their percentages of occurrence, were crabs (73%), clams (55%), snails (47%), amphipods (32%), shrimp (18%), mysids (13%), marine worms (13%) and cephalopods (4%). The most frequently occurring prey species were capelin, Mallotus villosus, (82%); codfishes, Gadidae (64%); narrow snow crab, Chionoecetes opilio (63%); eelpouts, Lycodes spp. (56%); longsnout prickleback, Lumpenella longirostris (49%); nutshell clams, Nuculana sp. (42%); and moon snails, Polinices sp. (27%). Seventy-seven percent of the seals examined had consumed prey from three or more different taxon groups. We identified seven food items not previously reported as prey of the bearded seal in the Bering Sea. No differences were detected between the diets of males and females and between adults and juveniles, indicating no apparent segregation of foraging by sex or age. Bearded seals in the St. Matthew Island region of the Bering Sea forage in a manner similar to their conspecifics in other areas where fish constitute a major portion of their diet. Prey selection is probably dependent on availability, and diet may be highly diversified even within a relatively small area during a short period of time. Variety in prey consumption exemplified the ability of the bearded seal to forage in the seasonally changing habitat associated with the advance and retreat of the ice front.Key words: bearded seal, Erignathus barbatus, diet, demersal and pelagic fish, benthic invertebrates, prey species diversity On a étudié le régime alimentaire du phoque barbu, Erignathus barbatus, près de l'île Saint Matthew dans la mer de Béring, tôt au printemps de 1981. Quatre-vingt six p. cent des 78 estomacs de phoques examinés contenaient du poisson. Parmi les autres groupes de taxons servant de proies, on retrouvait, par pourcentages décroissants, les crabes (73 p. cent), les myes (55 p. cent), les gastéropodes (47 p. cent), les amphipodes (32 p. cent), les crevettes (18 p. cent), les mysis (13 p. cent), les vers marins (13 p. cent) et les céphalopodes (4 p. cent). Les espèces de proies les plus courantes étaient le capelan, Mallotus villosus (82 p. cent); la morue, Gadidae (64 p. cent); le crabe des neiges, Chionoecetes opilio (63 p. cent); la lotte, sp. Lycodes (56 p. cent); Lumpenella longirostris (49 p. cent); sp. Nuculana (42 p. cent); et la natice, sp. Polinices (27 p. cent). Soixante-dix-sept p. cent des phoques étudiés avaient ingéré des proies venant d'au moins trois différents groupes de taxons. On a identifié sept produits alimentaires qui n'avaient pas encore été reportés comme constituant une proie pour le phoque barbu dans la mer de Béring. On n'a détecté aucune différence entre les régimes alimentaires des mâles et ceux des femelles, ni entre ceux des adultes et ceux des petits, ce qui indique qu'il n'existe apparemment pas de ségrégation quant au sexe ou à l'âge lors du comportement visant la quête de nourriture. Les phoques barbus de la région de l'île Saint Matthew dans la mer de Béring recherchent leur nourriture comme leurs congénères dans d'autres régions où le poisson constitue une grande partie de leur régime. La sélection des proies dépend probablement de leur disponibilité et le régime peut être hautement diversifié, même dans une zone relativement petite et durant une courte période. La variété qui se manifeste dans la consommation des proies montre bien la capacité du phoque barbu à rechercher sa nourriture dans un habitat qui varie selon les saisons et est associé à l'avancée et au retrait du front glaciaire.Mots clés: phoque barbu, Erignathus barbatus, régime alimentaire, poissons démersaux et pélagiques, invertébres benthiques, variété des espèces servant de proi

    Vesuvianite From Pajsberg, Sweden, and the Role of Be In the Vesuvianite Structure

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    Vesuvianite from Pajsberg, Sweden contains about one atom of Mn, based on 50 cations per formula unit, and small amounts of Be, B, and As. Optical absorption analysis suggests that the Mn is predominantly or entirely trivalent. Crystal-structure analysis indicates that Mn is housed at the general octahedral site Y3, which exhibits only minor distortion from ideal octahedral symmetry. Arsenic is housed at Y2 and Z2, and the formula derived from electron microprobe and LA-ICP-MS analyses suggests minor substitution of Al for Si, also at Z2. Beryllium and B are at T1, between the edge-sharing trimers Y3Y2Y3, as is the case for B in the boron-dominant vesuvianite species wiluite. The total content at T1 is interpreted as 0.82Be, 0.34B, and 0.037Fe^(3+)

    Causal inference in multi-cohort studies using the target trial approach

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    Longitudinal cohort studies provide the opportunity to examine causal effects of complex exposures on long-term health outcomes. Utilizing data from multiple cohorts has the potential to add further benefit by improving precision of estimates through data pooling and allowing examination of effect heterogeneity across contexts. However, the interpretation of findings can be complicated by biases that may be compounded when pooling data or may contribute to discrepant findings when analyses are replicated across cohorts. Here we extend the target trial framework, already well established as a powerful tool for causal inference in single-cohort studies, to address the specific challenges that can arise in the multi-cohort setting. The approach considers the target trial as a central point of reference, as opposed to comparing one study to another. This enables clear definition of the target estimand and systematic consideration of sources of bias within each cohort and additional sources of bias arising from data pooling. Consequently, analyses can be designed to reduce these biases and the resulting findings appropriately interpreted. We use a case study to demonstrate the approach and its potential to strengthen causal inference in multi-cohort studies through improved analysis design and clarity in the interpretation of findings.Comment: 34 pages, 3 figure

    Mathews County Dune Inventory

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    Mathews County, Virginia is located along the western shore of Chesapeake Bay and is at the eastern end of Virginia’s Middle Peninsula (Figure 1). Eighteen dune sites were identified along the Mathews County shoreline by site visits performed in 1999 and 2000. Of those 18 sites, 13 are located on Chesapeake Bay (Figure 2). It is the intent of this publication to provide the user with information on the status of dunes in Mathews County. This information comes from research performed in 1999 and 2000 which was presented in a report entitled “Chesapeake Bay Dune Systems: Evolution and Status (Hardaway et al., 2001). Since much of the data was collected several years ago and the beach and dune systems may have changed, this report is intended only as a resource for coastal zone managers and homeowners; it is not intended for use in determining legal jurisdictional limits
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