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Timo J. Ruokonen Mikko Kiljunen Jaakko Erkinaro Panu Orell Olli Sivonen Eero Vestola Roger I. Jones 《Ecology of Freshwater Fish》2019,28(1):53-61
We estimated the proportions of anadromous and freshwater‐resident brown trout (Salmo trutta) in different parts of the subarctic River Näätämöjoki/Neidenelva system (Finland and Norway) using carbon, nitrogen and hydrogen stable isotope analyses of archived scales as identifiers of migration strategy. Our results showed that carbon stable isotope values were the best predictor of migration strategy. Most individuals fell into two clearly distinct groups representing anadromous (47%) or freshwater‐resident (42%) individuals, but some fish had intermediate carbon values suggesting repeated movement between freshwater and the sea. The proportion of anadromous individuals decreased steadily with distance from the sea forming a spatial continuum in migration strategies which is probably maintained by the combination of several factors such as divergent availability of food resources, variable migration costs and genetic differences. These within‐catchment differences in migration strategies should be taken into account in fisheries management practices. 相似文献
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Masahiro Natsume Asaho Nagagata Marja Aittamaa Naoko Okaniwa Panu Somervuo Hans-Peter Fiedler Jan F. Kreuze Veli-Matti Rokka Hans Bång Hiroshi Kawaide Jari P. T. Valkonen 《Journal of General Plant Pathology》2018,84(2):108-117
Streptomyces spp. are a highly diverse group of bacteria most of which are soil-inhabiting saprophytes. A few are plant pathogens that produce a family of phytotoxins called thaxtomins and cause significant economic losses, e.g., by reducing the marketability of potato tubers (Solanum tuberosum). In northern Europe, S. scabies, S. turgidiscabies and S. europaeiscabiei are the most common plant pathogenic species. In this study, a Streptomyces strain isolated from a netted scab lesion on a tuber of potato cv. Bintje in northern Sweden was identified as S. turgidiscabies but was found to differ in the genomic region carrying genes required for thaxtomin biosynthesis. Our results showed that the strain did not produce thaxtomin but rather phytotoxin fridamycin E, which is an anthraquinone novel to plant pathogenic Streptomyces spp. Fridamycin E was shown to reduce or inhibit sprouting of potato microtubers in vitro. While fridamycin E is known to have antibiotic activity against Gram-positive bacteria, the inhibitory activity of fridamycin E on plant growth is a novel finding. 相似文献
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Effects of tagging on migration behaviour,survival and growth of hatchery‐reared Atlantic salmon smolts 下载免费PDF全文
R. Huusko A. Huusko A. Mäki‐Petäys P. Orell J. Erkinaro 《Fisheries Management and Ecology》2016,23(5):367-375
The effects of four different tagging methods (PIT, anchor T‐tag, Carlin tag and dummy radio transmitter) on survival, behaviour and growth of Atlantic salmon smolts during their downstream migration were examined in semi‐natural circular channels during a natural migration period in spring. Survival of smolts was high and tagging wounds healed well in all tagging groups. Tag loss rates were generally low, being the highest (2.5%) in the dummy radio transmitter group. Total length and body mass of the tagged and untagged smolts did not differ at the end of the experiment. Migration activity of smolts generally showed similar patterns among the treatments. However, Carlin‐tagged smolts started their migration slightly later than the PIT‐tagged fish, and smolts tagged with Carlin tag or dummy radio transmitter showed less overall migration activity than fish with PIT tag. 相似文献
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Maarit Termonen Panu Korhonen Sanna Kykkänen Anna Kärkönen Minna Toivakka Raimo Kauppila Perttu Virkajärvi 《Grass and Forage Science》2020,75(1):111-126
Finnish N fertilizer application regulations for forage grasses are based on field experiments mainly conducted in the 1960–1970s with cultivars and management practices typical of the time. In order to update the yield response function of N, to make it better suited to current grassland farming, field experiments were conducted at two sites in 2015–2017 with two cultivars of timothy (Phleum pratense L.) and one of meadow fescue (Festuca pratensis Huds.). Dry matter (DM) yield, nutritive value and N balance were evaluated, with N application levels 0, 150, 200, 250, 300, 350, 400 and 450 kg N ha−1 year−1. The grasses were harvested three times per season. The data indicate that the DM yield response was significantly stronger, and N was used more efficiently for DM production than earlier without compromising the nutritive value, especially during the first two years. The third harvest produced on average 23% of the annual yield, utilizing N efficiently. N application rates below 350 kg N ha−1 year−1 did not cause substantial overwintering losses or lodging. The data indicate that with changing climate and improved cultivars and management practices, there is a need to modify the rates and timing of N application. The results suggest that N application levels could be increased by at least 50 kg N ha−1 year−1 from the current maximum accepted rate (250 kg N ha−1 year−1) without too high NO3- or CP concentrations in feed, or too high N balance that indicates increasing risk of N leaching. 相似文献
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Vertical and horizontal distribution of ascending Atlantic salmon in power plant tailrace channels 下载免费PDF全文
Tapio Sutela Panu Orell Ari Huusko Mikko Jaukkuri Riina Huusko Aki Mäki‐Petäys Jaakko Erkinaro 《Fisheries Management and Ecology》2018,25(4):267-274
Three‐dimensional distribution of adult upstream‐migrating Atlantic salmon, Salmo salar L., was studied in three power plant tailrace channels on the large, regulated River Kemijoki in northern Finland using novel pressure sensor radio telemetry. The salmon swam mostly at depths of 1–4 m below the surface, with the salmon‐specific averages ranging from 1.3 to 6.4 m. When approaching a power plant, no change in swimming depth was observed. The horizontal locations of salmon in the two regularly shaped tailrace channels peaked at 5–10 m distance from the shoreline and showed a positively skewed distribution with a tail towards the central part of the tailrace. A graphical presentation of salmon locations in the tailrace channel and data on swimming depth and distance from the shoreline may prove useful in determining the location and design of a fishway entrance and in dimensioning attraction flow. 相似文献
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T. Linnansaari A. Keskinen A. Romakkaniemi J. Erkinaro P. Orell 《Ecology of Freshwater Fish》2010,19(4):618-626
Linnansaari T, Keskinen A, Romakkaniemi A, Erkinaro J, Orell P. Deep habitats are important for juvenile Atlantic salmon Salmo salar L. in large rivers. Ecology of Freshwater Fish 2010: 19: 618–626. © 2010 John Wiley & Sons A/S Abstract – Juvenile Atlantic salmon were studied by underwater video surveillance and self contained underwater breathing apparatus‐diving in deep (i.e. >1.0 m), fast flowing areas of two large river systems (River Teno, River Tornionjoki) in northern Finland. Both video and diving data indicated that young‐of‐the‐year (YOY) salmon (0+) and salmon parr (>0+) readily utilised habitats deeper than 1 m. Young‐of‐the‐year salmon and parr were observed through a range of 0.5–1.9 m and 0.4–2.2 m, respectively. A negative linear relationship between the mean abundance of YOY salmon and mean depth was noted from the diving transects. Salmon parr were similarly abundant throughout the range of depths studied. Video data showed that deep habitats were used throughout the summer (June–August). It was concluded that deep, fast‐flowing areas in large rivers may constitute a significant habitat resource for juvenile salmon that has not been traditionally accounted for when estimating salmon production. 相似文献
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Teppo Vehanen Pauliina Louhi Ari Huusko Aki Mki‐Petys Olli van der Meer Panu Orell Riina Huusko Mikko Jaukkuri Tapio Sutela 《Fisheries Management and Ecology》2020,27(1):41-51
In hydropeaking rivers, flow regulation typically follows demands in electricity consumption. One hundred and twenty one adult salmon were tagged with radio transmitters to study their spawning run migration patterns in hydropeaking conditions. The fish were released in small groups into the rivers Kemijoki and Iijoki, in Finland. Typically, salmon made subsequent up‐ and downstream movements ascending upstream to the tailrace of the power station and then descending again downstream to lower water velocities. The rate of these migration attempts was higher in mid‐summer and at relatively high flows. On an hourly basis, the pattern of migration attempts followed a trend of increasing attempts at dawn and higher discharges and a decreasing trend towards dusk and low flows. It was concluded that day length and discharge were the most important environmental factors, while temperature had less effect on the pattern of migration attempts. 相似文献