DNA barcoding is an invaluable tool to identify clitellates, regardless of life stage or cryptic morphology. However, as COI (the standard barcode for animals) is relatively long (658 bp), sequencing it requires DNA of high quality. When DNA is fragmented due to degradation, alternative barcodes of shorter length present an option to obtain genetic material. We attempted to sequence 187 clitellates sampled from springs in Iceland. However, the material had been stored at room temperature for two years, and DNA of the worms had degraded, and only three COI sequences were produced (i.e., <2% success rate). Using two alternative barcodes of 16S (one ca. 320 bp, the other ca. 70 bp long) we increased the number of sequenced specimens to 51. Comparisons of the 16S sequences showed that even the short 70 bp fragment contained enough genetic variation to separate all clitellate species in the material. Combined with morphological examinations we recognized a total of 23 species, where at least 8 are new records for Iceland, some belonging to genera new for Iceland: Cernosvitoviella and Pristina. All the new taxa are included in an updated species list of Icelandic Clitellata. The material revealed some stygophilic species previously known to inhabit springs, but true stygobionts, which are restricted to groundwater habitats, were not found. Our study shows that short 16S fragments can be obtained from DNA too degraded to be used in traditional COI barcoding, and contain enough genetic variation to separate closely related clitellate species.
{"title":"Investigating the Clitellata (Annelida) of Icelandic springs with alternative barcodes","authors":"Mårten Klinth, A. Kreiling, C. Erséus","doi":"10.5324/fn.v39i0.3043","DOIUrl":"https://doi.org/10.5324/fn.v39i0.3043","url":null,"abstract":"DNA barcoding is an invaluable tool to identify clitellates, regardless of life stage or cryptic morphology. However, as COI (the standard barcode for animals) is relatively long (658 bp), sequencing it requires DNA of high quality. When DNA is fragmented due to degradation, alternative barcodes of shorter length present an option to obtain genetic material. We attempted to sequence 187 clitellates sampled from springs in Iceland. However, the material had been stored at room temperature for two years, and DNA of the worms had degraded, and only three COI sequences were produced (i.e., <2% success rate). Using two alternative barcodes of 16S (one ca. 320 bp, the other ca. 70 bp long) we increased the number of sequenced specimens to 51. Comparisons of the 16S sequences showed that even the short 70 bp fragment contained enough genetic variation to separate all clitellate species in the material. Combined with morphological examinations we recognized a total of 23 species, where at least 8 are new records for Iceland, some belonging to genera new for Iceland: Cernosvitoviella and Pristina. All the new taxa are included in an updated species list of Icelandic Clitellata. The material revealed some stygophilic species previously known to inhabit springs, but true stygobionts, which are restricted to groundwater habitats, were not found. Our study shows that short 16S fragments can be obtained from DNA too degraded to be used in traditional COI barcoding, and contain enough genetic variation to separate closely related clitellate species.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46483926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Examination of Paradulichia-material collected from the Barents Sea during the Mareano cruisesindicated that there are clear morphological differences between Paradulichia typica Boeck, 1871from the Hardangerfjord, W. Norway and Paradulichia spinifera Gurjanova, 1946 from the Arctic.Based on our material and the original descriptions, these differences are the acute ventral parts of thebody segments, the triangularly shaped coxal plates 3 and 4, the shape and length of the mandible palparticles, the long merus of pereopods 5 and 6, the elongate telson and the 2-articulate rami of uropod 2.
{"title":"Paradulichia spinifera Gurjanova, 1946 (Amphipoda, Dulichiidae), a valid species?","authors":"P. Johansen, W. Vader","doi":"10.5324/fn.v39i0.2993","DOIUrl":"https://doi.org/10.5324/fn.v39i0.2993","url":null,"abstract":"Examination of Paradulichia-material collected from the Barents Sea during the Mareano cruisesindicated that there are clear morphological differences between Paradulichia typica Boeck, 1871from the Hardangerfjord, W. Norway and Paradulichia spinifera Gurjanova, 1946 from the Arctic.Based on our material and the original descriptions, these differences are the acute ventral parts of thebody segments, the triangularly shaped coxal plates 3 and 4, the shape and length of the mandible palparticles, the long merus of pereopods 5 and 6, the elongate telson and the 2-articulate rami of uropod 2.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46865320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Arctic tadpole shrimp Lepidurus arcticus has a circumpolar distribution where the Hardangervidda mountain plateau in Norway marks its southernmost limit. Within this area, we searched for L. arcticus in 238 lakes in 27 catchments. On Hardangervidda, the distribution pattern of L. arcticus is highly skewed. In the 16 catchments located in the central and eastern parts, L. arcticus was recorded in 70% of all the lakes studied (n=191). The remaining 11 catchments located in western areas, are almost free of lakes with L. arcticus (n=47). The most striking difference between these two areas is the significantly higher level of snow deposition in the western areas. This delays the ice break-up, which results in lower water temperatures and a shorter growing season. The water of lakes in western areas (N=36) is also more dilute than those in the central and eastern areas (N=201), with mean calcium concentrations of 0.81±0.48 and 1.62±1.12 mg L-1, respectively. In the lakes in the central and eastern areas hosting L. arcticus (N=95), the mean value was slightly higher (1.67±1.14 mg L-1). The combination of low water temperature, a short growing season and dilute water low in calcium may explain the near total absence of L. arcticus in the western part of Hardangervidda. All lakes contain brown trout Salmo trutta, and as L. arcticus is heavily sought for as food, the analyses of fish stomachs are the most reliable method of detecting the species. However, this prey-predator relationship may severely reduce the population of L. arcticus, and their presence may also be a function of the proximity of species refugia. This is evident in the context of fish predation, but also of water quality. Hence, in the central and eastern parts of the plateau, where L. arcticus is common, their occurrence increased significantly with lake size, being found in 54% of the lakes <1.0 km2, as opposed to 97% in the bigger lakes. Furthermore, L. arcticus is most frequently found in lakes at altitudes between 1100 and 1299 m a.s.l. We conclude that environmental constraints limit the distribution of L. arcticus on Hardangervidda. The projected increase in temperature towards the end of this century may exterminate L. arcticus from the lower parts of Hardangervidda, especially in the most shallow lakes. Many of the lakes have water quality with pH <6.0 and calcium concentration <1.0 mg L-1. In such lakes L. arcticus is living on the edge of its survival, and the projected increase in precipitation may dilute the waters even further, pushing L. arcticus nearer to its extinction threshold.
{"title":"Environmental conditions limit the distribution of Lepidurus arcticus (Branchiopoda, Notostraca) in lakes on the Hardangervidda mountain plateau, Southern Norway","authors":"T. Qvenild, T. Hesthagen","doi":"10.5324/FN.V39I0.2687","DOIUrl":"https://doi.org/10.5324/FN.V39I0.2687","url":null,"abstract":"The Arctic tadpole shrimp Lepidurus arcticus has a circumpolar distribution where the Hardangervidda mountain plateau in Norway marks its southernmost limit. Within this area, we searched for L. arcticus in 238 lakes in 27 catchments. On Hardangervidda, the distribution pattern of L. arcticus is highly skewed. In the 16 catchments located in the central and eastern parts, L. arcticus was recorded in 70% of all the lakes studied (n=191). The remaining 11 catchments located in western areas, are almost free of lakes with L. arcticus (n=47). The most striking difference between these two areas is the significantly higher level of snow deposition in the western areas. This delays the ice break-up, which results in lower water temperatures and a shorter growing season. The water of lakes in western areas (N=36) is also more dilute than those in the central and eastern areas (N=201), with mean calcium concentrations of 0.81±0.48 and 1.62±1.12 mg L-1, respectively. In the lakes in the central and eastern areas hosting L. arcticus (N=95), the mean value was slightly higher (1.67±1.14 mg L-1). The combination of low water temperature, a short growing season and dilute water low in calcium may explain the near total absence of L. arcticus in the western part of Hardangervidda. All lakes contain brown trout Salmo trutta, and as L. arcticus is heavily sought for as food, the analyses of fish stomachs are the most reliable method of detecting the species. However, this prey-predator relationship may severely reduce the population of L. arcticus, and their presence may also be a function of the proximity of species refugia. This is evident in the context of fish predation, but also of water quality. Hence, in the central and eastern parts of the plateau, where L. arcticus is common, their occurrence increased significantly with lake size, being found in 54% of the lakes <1.0 km2, as opposed to 97% in the bigger lakes. Furthermore, L. arcticus is most frequently found in lakes at altitudes between 1100 and 1299 m a.s.l. We conclude that environmental constraints limit the distribution of L. arcticus on Hardangervidda. The projected increase in temperature towards the end of this century may exterminate L. arcticus from the lower parts of Hardangervidda, especially in the most shallow lakes. Many of the lakes have water quality with pH <6.0 and calcium concentration <1.0 mg L-1. In such lakes L. arcticus is living on the edge of its survival, and the projected increase in precipitation may dilute the waters even further, pushing L. arcticus nearer to its extinction threshold.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43328908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The taxonomic identity of the palaeonemertean Cephalothrix linearis (Rathke, 1799) has been obscure for nearly two centuries, because its original description applies to almost any congeners, including Cephalothrix filiformis (Johnston 1828) and Cephalothrix rufifrons (Johnston, 1837), which occur commonly in the North Sea and adjacent waters. In this paper, I redescribe C. linearis based on two topotypes from Bergen, one herein designated as the neotype for C. linearis, because Rathke’s original material is not extant; I invoke Article 70.3.2 of the International Code of Zoological Nomenclature to fix Planaria linearis Rathke, 1799 as the type species of Cephalothrix Örsted, 1843 for the sake of stability. From the neotype, I determined sequences of the 28S rRNA, 16S rRNA, and cytochrome c oxidase subunit I (COI) genes. Using the COI sequence, I inferred the phylogenetic position of C. linearis along with 316 cephalotrichid sequences currently available in public databases. A tree-based species delimitation analysis detected 43 entities among them, with 34 in Cephalothrix and nine in eitherBalionemertes or Cephalotrichella. I apply valid species names to 12 of the 34 entities in Cephalothrix. I tabulated a total of 36 nominal species that are likely the members of the genus; the following five were excluded even though their specific names were originally combined with Cephalothrix: Cephalothrix armata Ulyanin, 1870 [Monostilifera, possibly Emplectonema gracile (Johnston, 1837)], Cephalothrix fragilis Bürger, 1892 [now Cephalotrichella signata (Hubrecht, 1879)], Cephalothrix signata Hubrecht, 1879 [now in Cephalotrichella], Cephalothrix unipunctata Parfitt, 1867 [now Tetrastemma melanocephalum (Johnston, 1837) (Monostilifera)], and Cephalothrix viridis Chapuis, 1886 [possibly Heteronemertea]. The five names cephalothrix Diesing, 1850 (as Borlasia cephalothrix), kroyeri Diesing, 1850 (as Cephalothrix kroyeri), linearis Diesing, 1850 (as Borlasia linearis), lineata Claparède, 1862 (as Cephalothrix lineata), and oerstedii Diesing, 1850 (as Cephalothrix oerstedii) aredeclared nomenclaturally unavailable.
{"title":"Resolving a 200-year-old taxonomic conundrum: neotype designation for Cephalothrix linearis (Nemertea: Palaeonemertea) based on a topotype from Bergen, Norway","authors":"H. Kajihara","doi":"10.5324/fn.v39i0.2734","DOIUrl":"https://doi.org/10.5324/fn.v39i0.2734","url":null,"abstract":"The taxonomic identity of the palaeonemertean Cephalothrix linearis (Rathke, 1799) has been obscure for nearly two centuries, because its original description applies to almost any congeners, including Cephalothrix filiformis (Johnston 1828) and Cephalothrix rufifrons (Johnston, 1837), which occur commonly in the North Sea and adjacent waters. In this paper, I redescribe C. linearis based on two topotypes from Bergen, one herein designated as the neotype for C. linearis, because Rathke’s original material is not extant; I invoke Article 70.3.2 of the International Code of Zoological Nomenclature to fix Planaria linearis Rathke, 1799 as the type species of Cephalothrix Örsted, 1843 for the sake of stability. From the neotype, I determined sequences of the 28S rRNA, 16S rRNA, and cytochrome c oxidase subunit I (COI) genes. Using the COI sequence, I inferred the phylogenetic position of C. linearis along with 316 cephalotrichid sequences currently available in public databases. A tree-based species delimitation analysis detected 43 entities among them, with 34 in Cephalothrix and nine in eitherBalionemertes or Cephalotrichella. I apply valid species names to 12 of the 34 entities in Cephalothrix. I tabulated a total of 36 nominal species that are likely the members of the genus; the following five were excluded even though their specific names were originally combined with Cephalothrix: Cephalothrix armata Ulyanin, 1870 [Monostilifera, possibly Emplectonema gracile (Johnston, 1837)], Cephalothrix fragilis Bürger, 1892 [now Cephalotrichella signata (Hubrecht, 1879)], Cephalothrix signata Hubrecht, 1879 [now in Cephalotrichella], Cephalothrix unipunctata Parfitt, 1867 [now Tetrastemma melanocephalum (Johnston, 1837) (Monostilifera)], and Cephalothrix viridis Chapuis, 1886 [possibly Heteronemertea]. The five names cephalothrix Diesing, 1850 (as Borlasia cephalothrix), kroyeri Diesing, 1850 (as Cephalothrix kroyeri), linearis Diesing, 1850 (as Borlasia linearis), lineata Claparède, 1862 (as Cephalothrix lineata), and oerstedii Diesing, 1850 (as Cephalothrix oerstedii) aredeclared nomenclaturally unavailable.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45928835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Borgstrøm, Knut Bergum, T. Børresen, M. Svenning
Use of experimental gillnet fleets is common both in scientific studies of fish populations and in fishsampling for management purposes. Fish catchability may vary considerably with fish and gillnet meshsize, and catches obtained by gillnet fleets composed of nets with different mesh sizes may give lengthand age distributions that deviate considerably from the length and age structure of the population.We have estimated the absolute catchability of allopatric brown trout (Salmo trutta) in the littoral andpelagic habitat of a small lake based on a mark-recapture experiment. The brown trout catchabilityvaried considerably both with fish size and habitat type, probably due to a size-related variation inswimming distance per time unit and a size-related use of the different lentic habitats. The samplingbias in experimental gillnet fishing may be reduced by operating the gillnet fleets in all possible lentichabitats and most fundamentally, by use of catchability data obtained from populations with ‘known’length and age structures. By reducing this sampling bias, more realistic estimations of the age andlength distribution for a given population will be possible.
{"title":"Gillnet catchability of brown trout Salmo trutta is highly dependent on fish size and capture site","authors":"R. Borgstrøm, Knut Bergum, T. Børresen, M. Svenning","doi":"10.5324/FN.V39I0.2536","DOIUrl":"https://doi.org/10.5324/FN.V39I0.2536","url":null,"abstract":"Use of experimental gillnet fleets is common both in scientific studies of fish populations and in fishsampling for management purposes. Fish catchability may vary considerably with fish and gillnet meshsize, and catches obtained by gillnet fleets composed of nets with different mesh sizes may give lengthand age distributions that deviate considerably from the length and age structure of the population.We have estimated the absolute catchability of allopatric brown trout (Salmo trutta) in the littoral andpelagic habitat of a small lake based on a mark-recapture experiment. The brown trout catchabilityvaried considerably both with fish size and habitat type, probably due to a size-related variation inswimming distance per time unit and a size-related use of the different lentic habitats. The samplingbias in experimental gillnet fishing may be reduced by operating the gillnet fleets in all possible lentichabitats and most fundamentally, by use of catchability data obtained from populations with ‘known’length and age structures. By reducing this sampling bias, more realistic estimations of the age andlength distribution for a given population will be possible.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45742450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Wienerroither, O. Bjelland, Gjertrud Jensen, A. Sveistrup
The flatfish four-spot megrim (Lepidorhombus boscii) was registered in Norwegian waters, both in trawl catches and video observations. The records represent a considerable northward extension of the species. Specimens of up to 49 cm were measured, representing also a new maximum size for this species. The number of registrations has increased within the last years, indicating that the species got more common in this area.
{"title":"Teleostei, Scophthalmidae: four-spot megrim spotted in Norwegian waters","authors":"R. Wienerroither, O. Bjelland, Gjertrud Jensen, A. Sveistrup","doi":"10.5324/FN.V39I0.2872","DOIUrl":"https://doi.org/10.5324/FN.V39I0.2872","url":null,"abstract":"The flatfish four-spot megrim (Lepidorhombus boscii) was registered in Norwegian waters, both in trawl catches and video observations. The records represent a considerable northward extension of the species. Specimens of up to 49 cm were measured, representing also a new maximum size for this species. The number of registrations has increased within the last years, indicating that the species got more common in this area.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42829337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thirteen species in the amphipod family Gammaridae have been reported from Norway. This paper gives a survey of the distribution and habitat of all 13 species of the family Gammaridae occurring or expected to occur in Norwegian waters: both marine, brackish and fresh, including Svalbard, in addition to four species found in close neighbouring waters. It also provides a short history of the study of Gammaridae in Norway, as well as an illustrated identification key to all species in the area.
{"title":"Gammarid amphipods (Crustacea) in Norway, with a key to the species","authors":"W. Vader, A. Tandberg","doi":"10.5324/fn.v39i0.2873","DOIUrl":"https://doi.org/10.5324/fn.v39i0.2873","url":null,"abstract":"Thirteen species in the amphipod family Gammaridae have been reported from Norway. This paper gives a survey of the distribution and habitat of all 13 species of the family Gammaridae occurring or expected to occur in Norwegian waters: both marine, brackish and fresh, including Svalbard, in addition to four species found in close neighbouring waters. It also provides a short history of the study of Gammaridae in Norway, as well as an illustrated identification key to all species in the area.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42316355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ocean warming drives latitudinal shifts in the distribution of ectotherm species. The rate and magnitude of such shifts are constrained by physiology and behavioural thermoregulation. Here, we investigated the thermal preference and lower critical temperature (CTmin) in female edible crab Cancer pagurus, a decapod crustacean with an ongoing northward dispersal along the Norwegian coast. The temperature selected by individual crabs from a northern (latitude ~69°N) and southern (latitude ~62°N) location was examined in a horizontal gradient (5.5-14.5°C) under a simulated day and night light regime. Irrespective of origin, crabs showed pronounced responses to the light cycle – during the day crabs stayed inactive in the warm end of the gradient but during night they actively explored the entire gradient. A preferred temperature of ~13 °C (measured as mode of loggings) was identified for crabs at both locations. Righting reflex experiments of crabs exposed to a rapid temperature drop (7 - 1 °C at -0.1 °C/min) identified a CTmin of ~1.3 °C (i.e., the temperature at which 50% of crabs failed to right from an up-side-down position), and with no significant difference between locations (p > 0.05). Our results provide important information about the functional characteristics of edible crab, and are discussed in context of the biology and ongoing northward dispersal of the species.
{"title":"Thermal behaviour of edible crab Cancer pagurus Linnaeus, 1758 in coastal Norway","authors":"S. Bakke, S. Siikavuopio, J. S. Christiansen","doi":"10.5324/FN.V39I0.2738","DOIUrl":"https://doi.org/10.5324/FN.V39I0.2738","url":null,"abstract":"Ocean warming drives latitudinal shifts in the distribution of ectotherm species. The rate and magnitude of such shifts are constrained by physiology and behavioural thermoregulation. Here, we investigated the thermal preference and lower critical temperature (CTmin) in female edible crab Cancer pagurus, a decapod crustacean with an ongoing northward dispersal along the Norwegian coast. The temperature selected by individual crabs from a northern (latitude ~69°N) and southern (latitude ~62°N) location was examined in a horizontal gradient (5.5-14.5°C) under a simulated day and night light regime. Irrespective of origin, crabs showed pronounced responses to the light cycle – during the day crabs stayed inactive in the warm end of the gradient but during night they actively explored the entire gradient. A preferred temperature of ~13 °C (measured as mode of loggings) was identified for crabs at both locations. Righting reflex experiments of crabs exposed to a rapid temperature drop (7 - 1 °C at -0.1 °C/min) identified a CTmin of ~1.3 °C (i.e., the temperature at which 50% of crabs failed to right from an up-side-down position), and with no significant difference between locations (p > 0.05). Our results provide important information about the functional characteristics of edible crab, and are discussed in context of the biology and ongoing northward dispersal of the species.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48424391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Qvenild, E. Fjeld, A. Fjellheim, S. Rognerud, Åsmund Tysse
On the Norwegian mainland, the Arctic tadpole shrimp Lepidurus arcticus is a typically alpine species mainly co-occurring with fish. The Hardangervidda mountain plateau is the main area of the southernmost L. arcticus populations. Here L. arcticus is widely distributed, especially in the central and eastern parts of the plateau. Lepidurus arcticus has a univoltine life cycle emerging from resting eggs at ice break-up and fulfil development during the short mountain summer, before they reproduce and die. The main goal in this study was to investigate the thermal thresholds for L. arcticus. Timing of ice break-up and the proceeding water temperature are hypothesized to constitute the primary drivers of L. arcticus's development and growth. Stomach analyses of brown trout is the most sensitive method for sampling L. arcticus, especially at low densities. Analyses of 4 460 brown trout stomachs revealed that at least 400 degree-days are needed for development and growth from hatching in to adults. It is a significant gradient in climatic conditions on Hardangervidda with a coastal impact in the western part of the plateau with a three - to fourfold winter deposition compared to a dryer inland region in the east. The snow deposits have increased since the 1980s and snow rich winters have been more frequent. An additional increase is projected. This may give lower water temperature and shorter ice-free seasons. Thus, the cold western lakes could be even more hostile habitats for L. arcticus. During the same period, an abrupt increase in spring-summer temperatures was detected. This has improved the conditions for L. arcticus in many lakes. However, as a cold stenotherm species a further increase in temperature may be detrimental. Especially in shallow lakes in the central and eastern parts this may be a problem even without reaching critical levels by inducing life cycle mismatches.
{"title":"Climatic effects on a cold stenotherm species Lepidurus arcticus (Branchiopoda, Notostraca) on the southern outreach of its distribution range","authors":"T. Qvenild, E. Fjeld, A. Fjellheim, S. Rognerud, Åsmund Tysse","doi":"10.5324/FN.V38I0.2598","DOIUrl":"https://doi.org/10.5324/FN.V38I0.2598","url":null,"abstract":"On the Norwegian mainland, the Arctic tadpole shrimp Lepidurus arcticus is a typically alpine species mainly co-occurring with fish. The Hardangervidda mountain plateau is the main area of the southernmost L. arcticus populations. Here L. arcticus is widely distributed, especially in the central and eastern parts of the plateau. Lepidurus arcticus has a univoltine life cycle emerging from resting eggs at ice break-up and fulfil development during the short mountain summer, before they reproduce and die. The main goal in this study was to investigate the thermal thresholds for L. arcticus. Timing of ice break-up and the proceeding water temperature are hypothesized to constitute the primary drivers of L. arcticus's development and growth. Stomach analyses of brown trout is the most sensitive method for sampling L. arcticus, especially at low densities. Analyses of 4 460 brown trout stomachs revealed that at least 400 degree-days are needed for development and growth from hatching in to adults. It is a significant gradient in climatic conditions on Hardangervidda with a coastal impact in the western part of the plateau with a three - to fourfold winter deposition compared to a dryer inland region in the east. The snow deposits have increased since the 1980s and snow rich winters have been more frequent. An additional increase is projected. This may give lower water temperature and shorter ice-free seasons. Thus, the cold western lakes could be even more hostile habitats for L. arcticus. During the same period, an abrupt increase in spring-summer temperatures was detected. This has improved the conditions for L. arcticus in many lakes. However, as a cold stenotherm species a further increase in temperature may be detrimental. Especially in shallow lakes in the central and eastern parts this may be a problem even without reaching critical levels by inducing life cycle mismatches.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70786299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arctic charr in Lake Ronvatn, a mountain lake in southern Norway was re-established through stocking. The population went extinction during the early 1980s due to acidification, when the lake was highly acidified with a mean pH of 5.2-5.4 with occasional declines to 4.3-4.7. However, from the mid to late 1990s, the pH and acid-neutralising capacity (ANC) of the lake rose to 5.8-5.9 and 13-15 µeq L-1, respectively. The lake is extremely dilute with a mean conductivity and calcium concentration of 7.7 µS cm-1 and 0.35 mg L-1, respectively. The lake was stocked with 250 Arctic charr from a neighbouring lake between 1998 and 2000. These introductions were highly successful, as test-fishing in 2004, 2008 and 2012 revealed a relatively dense population of Arctic charr, and the presence of several young age groups. Water quality has remained stable since the late 1990s, or has slightly improved.
{"title":"Arctic charr (Salvelinus alpinus) re-established in a formerly acidified and highly dilute mountain lake under declining acidic deposition","authors":"T. Hesthagen, R. Saksgård","doi":"10.5324/FN.V38I0.2272","DOIUrl":"https://doi.org/10.5324/FN.V38I0.2272","url":null,"abstract":"Arctic charr in Lake Ronvatn, a mountain lake in southern Norway was re-established through stocking. The population went extinction during the early 1980s due to acidification, when the lake was highly acidified with a mean pH of 5.2-5.4 with occasional declines to 4.3-4.7. However, from the mid to late 1990s, the pH and acid-neutralising capacity (ANC) of the lake rose to 5.8-5.9 and 13-15 µeq L-1, respectively. The lake is extremely dilute with a mean conductivity and calcium concentration of 7.7 µS cm-1 and 0.35 mg L-1, respectively. The lake was stocked with 250 Arctic charr from a neighbouring lake between 1998 and 2000. These introductions were highly successful, as test-fishing in 2004, 2008 and 2012 revealed a relatively dense population of Arctic charr, and the presence of several young age groups. Water quality has remained stable since the late 1990s, or has slightly improved.","PeriodicalId":35994,"journal":{"name":"Fauna Norvegica","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47095062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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