Comparison of genetic and morphological methods to detect the presence of American lobsters, Homarus americanus H. Milne Edwards, 1837 (Astacidea: Nephropidae) in Norwegian waters

American lobsters (Homarus americanus H. Milne Edwards, 1837) are imported live to Europe and should according regulations be kept in land-based tanks until sold. In spite of the strict regulations aimed specifically at preventing the introduction of this species into the NE Atlantic, several specimens of H. americanus have been captured in the wild, especially in Oslofjord, Norway since 1999. One of the great concerns is interbreeding between the introduced American species and the local European lobster, H. gammarus (Linnaeus, 1758). For this reason an awareness campaign was launched in 2000 focusing on morphologically "unusual" lobsters caught in local waters. Morphological characters have been based on colour and sub-ventral spines on the rostrum. Two samples of H. americanus were used for comparisons, as well as samples of European lobster from Oslofjord collected in 1992. Previous genetic analyses (allozymes, mtDNA and microsatellite DNA) have demonstrated that the American lobster is distinct from its European counterpart, with several additional alleles at many loci in addition to different allelic frequency distribution of alleles of "shared" alleles. During the present study, thirteen microsatellite loci were tested in the initial screening, and the three most discriminating loci (Hgam98, Hgam197b and Hgam47b) were used in a detailed comparison between the two species. A total of 45 unusual lobsters were reported captured from Ålesund (west) to Oslofjord (southeast) from 2001 to 2005 and these were analysed for the three microsatellite loci. Nine specimens were identified as American lobsters. Comparisons between morphological and genetic characteristics revealed that morphological differences are not reliable in discrimination the two species, or to identify hybrids. Further, some loci display almost no overlapping in allele frequency distribution for the reference samples analysed, thus providing a reliable tool to identify hybrids.

The lifetime direct cost of periodontal treatment:A case study from a norwegian specialist practice

Background: Successful periodontal treatment requires a commitment to regular lifelong maintenance and may be perceived by patients to be costly. This study calculates the total lifetime cost of periodontal treatment in the setting of a specialist periodontal practice and investigates the cost implications of choosing not to proceed with such treatment. Methods: Data from patients treated in a specialist practice in Norway were used to calculate the total lifetime cost of periodontal treatment that included baseline periodontal treatment, regular maintenance, retreatment, and replacing teeth lost during maintenance. Incremental costs for alternative strategies based on opting to forego periodontal treatment or maintenance and to replace any teeth lost with either bridgework or implants were calculated. Results: Patients who completed baseline periodontal treatment but did not have any additional maintenance or retreatment could replace only three teeth with bridgework or two teeth with implants before the cost of replacing additional teeth would exceed the cost of lifetime periodontal treatment. Patients who did not have any periodontal treatment could replace ≤4 teeth with bridgework or implants before a replacement strategy became more expensive. Conclusions: Within the limits of the assumptions made, periodontal treatment in a Norwegian specialist periodontal practice is cost-effective when compared to an approach that relies on opting to replace teeth lost as a result of progressive periodontitis with fixed restorations. In particular, patients who have initial comprehensive periodontal treatment but do not subsequently comply with maintenance could, on average, replace ≤3 teeth with bridgework or two teeth with implants before this approach would exceed the direct cost of lifetime periodontal treatment in the setting of the specialist practice studied. © 2012 American Academy of Periodontology.

Stock structure of Atlantic herring Clupea harengus in the Norwegian Sea and adjacent waters

The genetic structure of Atlantic herring Clupea harengus L. was investigated in its north-easterly distribution in the Norwegian Sea and adjacent waters, using 23 neutral and one non-neutral (Cpa111) microsatellite loci. Fish from the suspected 2 main populations - the Norwegian spring-spawning herring (NSSH) and the Icelandic summer-spawning herring (ISSH) - were collected at spawning locations in their respective spawning seasons from 2009 to 2012. Samples were also collected from Norwegian autumn spawning locations, from different local Norwegian fjords such as the inner part of Trondheimsfjorden, Lindås pollene, Landvikvannet and Lusterfjorden, as well as from suspected Faroese spawning components. The observed level of genetic differentiation was significant but low (F_ST = 0.007) and mostly attributable to the differentiation of the local Norwegian fjord populations. The locus Cpa111, which was detected to putatively be under positive selection, exhibited the highest FST value (0.044). The observed genetic patterns were robust to exclusion of this locus. Landvikvannet herring was also genetically distinguishable from the 3 other fjord populations. In addition, the present study does not support genetic structuring among the ISSH and the NSSH.

Sub-Arctic populations of European lobster (Homarus gammarus) in Northern Norway.

The European lobster is distributed throughout the south and western regions of the Norwegian coast. A previous lobster allozyme investigation (1993) in the Tysfjord region, north of the Arctic Circle demonstrated that the lobster population from this region was genetically different from lobster samples collected in other parts of Norway. More detailed investigation including supplementary extensive sampling and additional allozyme, microsatellite and mtDNA analyses are reported here. This investigation supports the genetic distinctness of the Tysfjord population and shows that this is mainly due to a reduction (60�70%) in gene diversity (observed heterozygosities and number of alleles) compared with lobsters from more southern regions. In addition to the Tysfjord region, the comprehensive sampling also included lobsters found in the adjacent Nordfolda fjord system. Genetic analyses provided evidence for significant differences between the lobster populations of Tysfjord and Nordfolda, even though they are separated by a coastal distance of only 142 km. The two populations were also different with regards to several biological characteristics such as body size. The genetic difference between these two geographically close populations is likely to be due to the local hydrological conditions, preventing larval dispersal between the fjord systems. Assessment of lobster abundance in the north-west region suggests that the sub-arctic lobster populations are geographically isolated.

Expressed sequence tag-derived microsatellites for the cool-water marine copepod Calanus finmarchicus

The copepod Calanus finmarchicus is the major contributor to zooplankton biomass in the North Atlantic and Norwegian Sea, but recent studies have shown a 70% decrease in abundance as well as a northward shift in the species' range. Insights into dispersal capabilities gained from population genetic studies will be crucial in predicting the response of C. finmarchicus communities to climate change and, consequently, we have developed a set of expressed sequence tag-derived microsatellite markers to allow fine-scale elucidation of population structuring and dispersal. Ten polymorphic markers displayed between two and 19 alleles, with levels of expected heterozygosity ranging from 0.044 to 0.924.

Effects of breed and production system on lameness parameters in dairy cattle

The aim of the present study was to assess the effects of Holstein-Friesian (HF) and Norwegian (N) dairy cattle genotypes on lameness parameters in dairy cattle within different production systems over the first 2 lactations. Following calving, HF (n = 39) and N (n = 45) heifers were allocated to 1 of 3 systems of production (high level of concentrate, low level of concentrate, and grass-based). High-and low-concentrate animals were continuously housed indoors on a rotational system so that they spent similar amounts of time on slatted and solid concrete floors. Animals on the grass treatment grazed from spring to autumn in both years of the study, so that most animals on this treatment grazed from around peak to late lactation. Claw health was recorded in both hind claws of each animal at 4 observation periods during each lactation as follows: 1) -8 to 70 d postcalving, 2) 71 to 150 d postcalving, 3) 151 to 225 d postcalving, and 4) 226 to 364 d postcalving. Sole lesions, heel erosion, axial wall deviation, sole length of the right lateral hind claw (claw length), right heel width, and right lateral hind heel height were recorded as well as the presence of digital dermatitis. The N cows had lower (better) white line and total lesion scores than HF cows. Cows on the high-and low-concentrate treatments had better sole and total lesion scores than cows on the grass treatment. The HF cows had better locomotion scores than N cows. Breed and production system differences were observed with respect to claw conformation, including claw length, heel width, and heel height. Digital dermatitis was associated with worse sole lesion scores and interacted with production system to influence white line lesion scores and maximum heel erosion scores. This study shows that genetic, environmental, and infectious factors are associated with hoof pathologies in dairy cows.

Mid- to late-Holocene climate variability and anthropogenic impacts: multi-proxy evidence from Lake Bliden, Denmark

We conducted multi-proxy geochemical analyses (including measurements of organic carbon, nitrogen and sulphur stable isotope composition, and carbonate carbon and oxygen isotope composition) on a 13.5 m sediment core from Lake Bliden, Denmark, which provide a record of shifting hydrological conditions for the past 6,700 years. The early part of the stratigraphic record (6,700-5,740 cal year BP) was wet, based on delta O-18(carb) and lithology, and corresponds to the Holocene Thermal Maximum. Shifts in primarily delta O-18(carb) indicate dry conditions prevailed from 5,740 to 2,800 cal year BP, although this was interrupted by very wet conditions from 5,300 to 5,150, 4,300 to 4,050 and 3,700 to 3,450 cal year BP. The timing of the latter two moist intervals is consistent with other Scandinavian paleoclimatic records. Dry conditions at Lake Bliden between 3,450 and 2,800 cal year BP is consistent with other paleolimnological records from southern Sweden but contrasts with records in central Sweden, possibly suggesting a more northerly trajectory of prevailing westerlies carrying moisture from the North Atlantic at this time. Overall, fluctuating moisture conditions at Lake Bliden appear to be strongly linked to changing sea surface temperatures in the Greenland, Iceland and Norwegian seas. After 2,800 cal year BP, sedimentology, magnetic susceptibility, delta C-13(ORG), delta C-13(carb) and delta O-18(carb) indicate a major reduction on water level, which caused the depositional setting at the coring site to shift from the profundal to littoral zone. The Roman Warm Period (2,200-1,500 cal year BP) appears dry based on enriched delta O-18(carb) values. Possible effects of human disturbance in the watershed after 820 cal year BP complicate attempts to interpret the stratigraphic record although tentative interpretation of the delta O-18(carb), magnetic susceptibility, delta C-13(ORG), delta C-13(carb) and delta O-18(carb) records suggest that the Medieval Warm Period was dry and the Little Ice Age was wet.