Prevalence of stocked whitefish in River Kemijoki,Finland, inferred by micro X‐ray fluorescence analysis of otoliths

Micro X‐ray fluorescence (µ‐XRF) analysis of otoliths was evaluated as a method to estimate the proportion of stocked one‐summer‐old whitefish Coregonus lavaretus L. in catches of adult fish (n = 20) ascending the River Kemijoki to spawn. Laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) analysis was applied as control. Polished otoliths were scanned with µ‐XRF to obtain strontium maps that were used to infer visually the provenance of the whitefish. Thirteen of the fish showed signs of being stocked as one‐summer‐old fingerlings. LA‐ICP‐MS was applied to determine the elemental composition in a spot outside the core of the otolith. The results were largely consistent with the visual inspection of the µ‐XRF mapped otoliths. In conclusion, µ‐XRF mapping successfully identified whitefish stocked as one‐summer‐old fingerlings. The vast majority of whitefish returning to the River Kemijoki to spawn were stocked fish.     

Stratospheric ozone, ultraviolet radiation, and cryptogams

The stratospheric ozone layer, which protects the biosphere from biologically active (mostly harmful) ultraviolet-B (UV-B) solar radiation, thinned during the latter half of the 20th century. In this paper some of the effects of UV-B radiation on cryptogams (cyanobacteria, algae, lichens, mosses, liverworts, pteridophytes and fungi) are reviewed. Effects vary among species, and therefore changes in UV-B radiation may affect species frequencies. Effects also depend on other factors, such as water conditions.     

Rotational position of curved saw logs and warp of the sawn timber

With the development of scanning technology in sawmills, it is possible to optimise log rotational position when sawing. However, choosing a different rotational position than horns down might be detrimental for the board shape after drying, especially for curved logs. Thus, there is a need to investigate at what level of log curve it is possible to freely rotate logs without causing board warp. This study was carried out through a test sawing that was conducted at a sawmill situated in the middle of Sweden. The tests were made on 177 Norway spruce logs, with varying amount of curve. Half of the logs were sawn in the horns-down position, half were sawn rotated perpendicular to horns down. Log shape and warp of the dried boards were measured. The results indicated a relationship between board spring, log curve and choice of rotational position. Furthermore, board bow was related to log curve but not rotational position. It can be concluded that for straight logs, with a bow height of less than 15 mm, an unconventional rotational position does not cause excess spring in the boards. Bow and twist are not affected by the rotational position at all.     

Galacturonic acid groups in birch xylan

Summary A large number of reducing xylose end groups are present in birch wood (Betula verrucosa) while all galacturonic acid moieties are non-reducing. A large portion of the reducing xylose end groups are removed during treatments with alkali used for the islation of xylan, while reducing galacturonic acid moieties are formed by endwise degradation during this procedure.The financial support from the 1959 Års Fond för Teknisk och Skoglig Forskning samt Utbildning is gratefully acknowledged.     

Beliefs about urban fringe forests among urban residents in Sweden

The aim of this study was to examine predictors of beliefs about urban fringe forests among urban residents in Sweden (n = 586). Based on a cognitive hierarchical model, the study investigated how socio-demographic variables, as well as different values and beliefs, were related to the more specific beliefs urban residents have about urban fringe forests. Results demonstrated that the urban fringe forest was perceived to be essential for personal wellbeing, but preservation and accessibility to the forest were also important. Certain differences between socio-demographic groups were identified; for example, the importance of urban fringe forests for personal wellbeing was emphasized more by women, older people and those with a university degree. However, the importance of socio-demographic variables was modest compared with the influence of people's values and beliefs. More specifically, results showed that urban residents’ basic values and ecological worldview, as well as forest values and beliefs (i.e., concerning forest qualities and forest requirements), were important in explaining their beliefs about urban fringe forests. Overall, the study revealed that urban residents are characterized by a heterogeneous set of beliefs concerning urban fringe forests. Recognizing these multiple beliefs in urban fringe forest development processes may help mitigate future conflicts between forest visitors, urban planners, forest owners and forest managers, thus enhancing our way toward good urban living environments.     

Heifer mastitis and dry-cow mastitis: A bacteriological survey in Sweden

A bacteriological investigation was performed on 145 heifers and 55 dry-cows with clinical mastitis during July 1976–June 1977. Areas in Sweden from which heifer and dry-cow mastitis has been reported as a problem were included. Mastitis occurred more frequently in the Swedish Fresian breed (SLB) than in the Swedish Red and White breed (SRB) of dairy cattle. C. pyogenes was isolated in pure culture from 15% and 4%, respectively, of the cases of heifer and dry-cow mastitis from which this bacterium could be isolated. Corresponding figures for pure culture of P. indolicus, micro-aerophilic cocci and S. dysgalactiae were 2% and 0%, 0% and 0% and 44% and 35%, respectively. The bacteria most frequently isolated together with C. pyogenes in the heifer material were P. indolicus (69%), the microaerophilic cocci (59%) and S. dysgalactiae (31%). Corresponding data for the dry-cow material were 92%, 35% and 50%, respectively. Thus, C. pyogenes was the causative agent of heifer and dry-cow mastitis in only about 40% of the mastitis cases investigated, and the most characteristic feature of these forms of mastitis involving C. pyogenes was mixed infection.     

Short feeding migration associated with a lower mean size of whitefish in the River Tornionjoki,northern Baltic Sea

The size of anadromous whitefish caught with dip nets in the River Tornionjoki in the northern part of the Gulf of Bothnia has decreased during recent decades. To find an explanation for this trend, ascending whitefish were sampled in the lower part of the river in August 2016, and they were divided into two groups according to fish length. The length of the SMALL group was ≤ 32 cm (n = 32) and that of the LARGE group ≥ 33 cm (n = 65). The elemental analysis of otoliths revealed that the barium concentration was clearly higher in otoliths from the SMALL group compared to the LARGE group. This indicates that the fish in the LARGE group had migrated to feed further south in the Gulf of Bothnia, with a higher salinity, than the fish in the SMALL group. Because of this migration difference, and a decline in the gillnet effort, especially in the feeding areas near the river mouth, it is assumed that proportionally more fish in the SMALL group are able to ascend the river to spawn than previously, thus decreasing the mean size. At the same time, the heavy gillnet fishery in the south removes fish from the LARGE group.