GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1
    Electronic Resource
    Electronic Resource
    MULTIVARIATE REGRESSION OF SATELLITE-LINKED DIVE RECORDER DATA: SIMULTANEOUS ANALYSIS OF ALL BINS (2005)
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 21 (2005), S. 0 
    Details
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Statistical analysis of diving behavior data collected from satellite-linked dive recorders (SDKs) can be challenging because: (1) the data are binned into several depth and time categories, (2) the data from individual animals are often temporally autocorrelated, (3) random variation between individuals is common, and (4) the number of dives can be correlated among depth bins. Previous analyses often have ignored one or more of these statistical issues. In addition, previous SDR studies have focused on univariate analyses of index variables, rather than multivariate analyses of data from all depth bins. We describe multivariate analysis of SDR data using generalized estimating equations (GEE) and demonstrate the method using SDR data from harbor seals (Phoca vitulina) monitored in Prince William Sound, Alaska between 1992 and 1997. Multivariate regression provides greater opportunities for scientific inference than univariate methods, particularly in terms of depth resolution. In addition, empirical variance estimation makes GEE models somewhat easier to implement than other techniques that explicitly model all of the relevant components of variance. However, valid use of empirical variance estimation requires an adequate sample size of individual animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1748-7692.2005.tb01226.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    WINTER FEEDING INTENSITY OF NARWHALS (MONODON MONOCEROS) (2005)
    Oxford, UK : Blackwell Publishing Ltd
    Marine mammal science 21 (2005), S. 0 
    Details
    ISSN: 1748-7692
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Stomach contents from 121 narwhals (Monondon monoceros) harvested in the eastern Canadian High Arctic and West Greenland were used to quantify seasonal changes in feeding activity and prey selection. Stomachs collected from summer harvests were mostly empty with little evidence of recent feeding. Stomachs collected in late fall and winter harvests had considerable amounts of undigested material with evidence of recent feeding. In summer, Arctic cod (Arctogadus glacialis), polar cod (Boreogadus saida), and Gonatus squid spp. constituted the narwhal diet. In fall, Gonatus fabricii was the only prey item observed. In late fall and winter, Greenland halibut (Reinhardtius hippoglossoides) and G. fabricii were the dominant prey items, observed in 51% and 73% of stomachs collected, respectively. Greenland halibut taken by narwhals were on average 39 cm (SD 8) and 556 g (306) and G. fabricii were on average 23 g (15) with mean mantle lengths of 85 mm (24). The low diversiry of prey species indicates narwhals have a restricted diet across all seasons. This study presents the first information on the winter diet of the narwhal and suggests Baffin Bay and Davis Strait are heavily utilized for feeding, in contrast to limited food intake during the summer period.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1748-7692.2005.tb01207.x
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    facet.materialart.
    Unknown
    Deep-ocean predation by a high Arctic cetacean (2004)
    Oxford University Press
    In:  ICES Journal of Marine Science, 61 (3). pp. 430-440.
    Details
    Publication Date: 2021-09-03
    Description: A bioenergetic model for two narwhal (Monodon monoceros) sub-populations was developed to quantify daily gross energy requirements and estimate the biomass of Greenland halibut (Reinhardtius hippoglossoides) needed to sustain the sub-populations for their 5-month stay on wintering grounds in Baffin Bay. Whales in two separate wintering grounds were estimated to require 700 tonnes (s.e. 300) and 90 tonnes (s.e. 40) of Greenland halibut per day, assuming a diet of 50% Greenland halibut. Mean densities and length distributions of Greenland halibut inside and outside of the narwhal wintering grounds were correlated with predicted whale predation levels based on diving behavior. The difference in Greenland halibut biomass between an area with high predation and a comparable area without whales, approximately 19 000 tonnes, corresponded well with the predicted biomass removed by the narwhal sub-population on a diet of 50–75% Greenland halibut.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1016/j.icesjms.2004.02.002
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 4
    facet.materialart.
    Unknown
    Passive acoustic monitoring reveals year-round marine mammal community composition off Tasiilaq, Southeast Greenland (2022)
    In:  EPIC3The Journal of the Acoustical Society of America, 151, pp. 1380-1392
    Details
    Publication Date: 2022-03-04
    Description: Climate-driven changes are affecting sea ice conditions off Tasiilaq, Southeast Greenland, with implications for marine mammal distributions. Knowledge about marine mammal presence, biodiversity, and community composition is key to effective conservation and management but is lacking, especially during winter months. Seasonal patterns of acoustic marine mammal presence were investigated relative to sea ice concentration at two recording sites between 2014 and 2018, with one (65.6°N, 37.4°W) or three years (65.5°N, 38.0°W) of passive acoustic recordings. Seven marine mammal species were recorded. Bearded seals were acoustically dominant during winter and spring, whereas sperm, humpback, and fin whales dominated during the sea ice-free summer and autumn. Narwhals, bowhead, and killer whales were recorded only rarely. Song-fragments of humpback whales and acoustic presence of fin whales in winter suggest mating-associated behavior taking place in the area. Ambient noise levels in 1/3-octave level bands (20, 63, 125, 500, 1000, and 4000 Hz), ranged between 75.6 to 105 dB re 1 μPa. This study provides multi-year insights into the coastal marine mammal community composition off Southeast Greenland and suggests that the Tasiilaq area provides suitable habitat for various marine mammal species year-round.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
    Format: application/pdf
    Format: application/zip
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...