Summer Residency of Pacific Halibut in Glacier Bay National Park

Glacier Bay National Park (Fig.1), as a Marine Protected Area (MPA), is phasing out commercial fishing of Pacific halibut (Hippoglossus stenolepis) within the park. The species continues to be commercially harvested outside of the bay

Multi-scale movement of demersal fishes in Alaska

Thesis (Ph.D.) University of Alaska Fairbanks, 2019Information on the movement of migratory demersal fishes such as Pacific halibut, Pacific cod, and sablefish is needed for management of these valuable fisheries in Alaska, yet available methods such as conventional tagging are too coarse to provide detailed information on migration characteristics. In this dissertation, I present methods for characterizing seasonal and annual demersal fish movement at multiple scales in space and time using electronic archival and acoustic tags. In Chapter 1, acoustic telemetry and the Net Squared Displacement statistic were used to identify and characterize small-scale movement of adult female Pacific halibut during summer foraging in a Marine Protected Area (MPA). The dominant movement pattern was home range behavior at spatial scales of less than 1 km, but a more dispersive behavioral state was also observed. In Chapter 2, Pop-up Satellite Archival Tags (PSATs) and acoustic tags were deployed on adult female Pacific halibut to determine annual movement patterns relative to MPA boundaries. Based on observations of summer home range behavior, high rates of year-round MPA residency, migration timing that largely coincided with winter commercial fisheries closures, and the demonstrated ability of migratory fish to return to previously occupied summer foraging areas, the MPA is likely to be effective for protecting both resident and migrant Pacific halibut brood stock year-round. In Chapter 3, I adapted a Hidden Markov Model (HMM) originally developed for geolocation of Atlantic cod in the North Sea for use on demersal fishes in Alaska, where maximum daily depth is the most informative and reliable geolocation variable. Because depth is considerably more heterogeneous in many regions of Alaska compared to the North Sea, I used simulated trajectories to determine that the degree of bathymetry heterogeneity affected model performance for different combinations of likelihood specification methods and model grid sizes. In Chapter 4, I added a new geolocation variable, geomagnetic data, to the HMM in a small-scale case study. The results suggest that the addition of geomagnetic data could increase model performance over depth alone, but more research is needed to continue validation of the method over larger areas in Alaska. In general, the HMM is a flexible tool for characterizing movement at multiple spatial scales and its use is likely to enrich our knowledge about migratory demersal fish movement in Alaska. The methods developed in this dissertation can provide valuable insights into demersal fish spatial dynamics that will benefit fisheries management activities such as stock delineation, stock assessment, and design of space-time closures.Rasmuson Fisheries Research Center and the Pollock Conservation Cooperative Research CenterChapter 1: Characterizing Pacific halibut movement and habitat in a Marine Protected Area using net squared displacement analysis methods -- Chapter 2: Interannual site fidelity of Pacific halibut: potential utility of protected areas for management of a migratory demersal fish -- Chapter 3 Effect of study area bathymetric heterogeneity on parameterization and performance of a depth depth-based geolocation model for demersal fishes -- Chapter 4 Potential utility of geomagnetic data for geolocation of demersal fish in the North Pacific Ocean -- General conclusion -- References -- Appendix A: Geolocation of demersal fishes in the North Pacific Ocean: Hidden Markov model framework and data likelihood models

Item analysis using Rasch models confirms that the Danish versions of the DISABKIDS (R) chronic-generic and diabetes-specific modules are valid and reliable

BACKGROUND: Type 1 Diabetes (T1D) has a negative impact on psychological and overall well-being. Screening for Health-related Quality of Life (HrQoL) and addressing HrQoL issues in the clinic leads to improved well-being and metabolic outcomes. The aim of this study was to translate the generic and diabetes-specific validated multinational DISABKIDS® questionnaires into Danish, and then determine their validity and reliability. METHODS: The questionnaires were translated using a validated translation procedure and completed by 99 children and adolescents from our diabetes-department; all diagnosed with T1D and were aged between 8 and 18 years old. The Rasch and the graphical log linear Rasch model (GLLRM) were used to determine validity. Monte Carlo methods and Cronbach’s α were used to confirm reliability. RESULTS: The data did not fit a pure Rasch model but did fit a GLLRM when item six in the independence scale is excluded. The six subscales measure different aspects of HrQoL indicating that all the subscales are necessary. The questionnaire shows local dependency between items and differential item functioning (DIF). Therefore age, gender, and glycated hemoglobin (HbA1c) levels must be taken into account when comparing HrQoL between groups. CONCLUSIONS: The Danish versions of the DISABKIDS® chronic-generic and diabetes-specific modules provide valid and objective measurements with adequate reliability. These Danish versions are useful tools for evaluating HrQoL in Danish patients with T1D. However, guidelines on how to manage DIF and local independence will be required, and item six should be rephrased. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12955-017-0618-8) contains supplementary material, which is available to authorized users

Introduktion: Politisk psykologi og eksperimenter: Nye krydsdisciplinære veje for statskundskaben

Introduktio