Fauna norvegica 2019-10-18T10:19:02+00:00 Fauna norvegica Open Journal Systems <p>Fauna norvegica is an international journal focusing on Nordic fauna. In addition to faunistic studies, contributions concerning systematics and taxonomy, biogeography, biodiversity in order to describe abundance and distribution, as well as methodological development, are welcome. Submitted manuscripts will be considered for publication after peer review. There are no page charges for manuscripts accepted for publication.</p> Thermal behaviour of edible crab Cancer pagurus Linnaeus, 1758 in coastal Norway 2019-10-18T10:19:02+00:00 Snorre Bakke Sten I Siikavuopio Jørgen Schou Christiansen <p>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 <em>Cancer pagurus</em>, 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 &gt; 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.</p> 2019-02-26T07:35:52+00:00 ##submission.copyrightStatement## Gammarid amphipods (Crustacea) in Norway, with a key to the species 2019-10-18T10:19:02+00:00 Wim Vader Anne Helene Solberg Tandberg <p>Thirteen species in the amphipod family Gammaridae have been reported from Norway. This paper&nbsp;gives a survey of the distribution and habitat of all 13 species of the family Gammaridae occurring&nbsp;or expected to occur in Norwegian waters: both marine, brackish and fresh, including Svalbard, in&nbsp;addition to four species found in close neighbouring waters. It also provides a short history of the study&nbsp;of Gammaridae in Norway, as well as an illustrated identification key to all species in the area.</p> 2019-02-28T07:42:02+00:00 ##submission.copyrightStatement## Gillnet catchability of brown trout Salmo trutta is highly dependent on fish size and capture site 2019-10-18T10:19:00+00:00 Reidar Borgstrøm Knut Bergum Trond Erik Børresen Martin A. Svenning <p>Use of experimental gillnet fleets is common both in scientific studies of fish populations and in fish<br>sampling for management purposes. Fish catchability may vary considerably with fish and gillnet mesh<br>size, and catches obtained by gillnet fleets composed of nets with different mesh sizes may give length<br>and age distributions that deviate considerably from the length and age structure of the population.<br>We have estimated the absolute catchability of allopatric brown trout (<em>Salmo trutta</em>) in the littoral and<br>pelagic habitat of a small lake based on a mark-recapture experiment. The brown trout catchability<br>varied considerably both with fish size and habitat type, probably due to a size-related variation in<br>swimming distance per time unit and a size-related use of the different lentic habitats. The sampling<br>bias in experimental gillnet fishing may be reduced by operating the gillnet fleets in all possible lentic<br>habitats and most fundamentally, by use of catchability data obtained from populations with ‘known’<br>length and age structures. By reducing this sampling bias, more realistic estimations of the age and<br>length distribution for a given population will be possible.</p> 2019-05-09T22:02:55+00:00 ##submission.copyrightStatement## Resolving a 200-year-old taxonomic conundrum: neotype designation for Cephalothrix linearis (Nemertea: Palaeonemertea) based on a topotype from Bergen, Norway 2019-10-18T10:18:59+00:00 Hiroshi Kajihara <p>The taxonomic identity of the palaeonemertean <em>Cephalothrix linearis</em> (Rathke, 1799) has been obscure&nbsp;for nearly two centuries, because its original description applies to almost any congeners, including&nbsp;<em>Cephalothrix filiformis</em> (Johnston 1828) and <em>Cephalothrix rufifrons</em> (Johnston, 1837), which occur&nbsp;commonly in the North Sea and adjacent waters. In this paper, I redescribe <em>C. linearis</em> based on two&nbsp;topotypes from Bergen, one herein designated as the neotype for <em>C. linearis</em>, because Rathke’s original&nbsp;material is not extant; I invoke Article 70.3.2 of the International Code of Zoological Nomenclature&nbsp;to fix <em>Planaria linearis</em> Rathke, 1799 as the type species of <em>Cephalothrix</em> Örsted, 1843 for the sake&nbsp;of stability. From the neotype, I determined sequences of the 28S rRNA, 16S rRNA, and cytochrome&nbsp;c oxidase subunit I (COI) genes. Using the COI sequence, I inferred the phylogenetic position of <em>C.&nbsp;linearis</em> along with 316 cephalotrichid sequences currently available in public databases. A tree-based&nbsp;species delimitation analysis detected 43 entities among them, with 34 in <em>Cephalothrix</em> and nine in either<br><em>Balionemertes</em> or <em>Cephalotrichella</em>. I apply valid species names to 12 of the 34 entities in <em>Cephalothrix</em>.&nbsp;I tabulated a total of 36 nominal species that are likely the members of the genus; the following&nbsp;five were excluded even though their specific names were originally combined with <em>Cephalothrix</em>:&nbsp;<em>Cephalothrix armata</em> Ulyanin, 1870 [Monostilifera, possibly <em>Emplectonema gracile</em> (Johnston, 1837)],&nbsp;<em>Cephalothrix fragilis</em> Bürger, 1892 [now <em>Cephalotrichella signata</em> (Hubrecht, 1879)], <em>Cephalothrix&nbsp;signata</em> Hubrecht, 1879 [now in <em>Cephalotrichella</em>], <em>Cephalothrix unipunctata</em> Parfitt, 1867 [now&nbsp;<em>Tetrastemma melanocephalum</em> (Johnston, 1837) (Monostilifera)], and <em>Cephalothrix viridis</em> Chapuis,&nbsp;1886 [possibly Heteronemertea]. The five names c<em>ephalothrix</em> Diesing, 1850 (as <em>Borlasia cephalothrix</em>),&nbsp;kroyeri Diesing, 1850 (as <em>Cephalothrix kroyeri</em>), <em>linearis</em> Diesing, 1850 (as <em>Borlasia linearis</em>), <em>lineata</em>&nbsp;Claparède, 1862 (as <em>Cephalothrix lineata</em>), and <em>oerstedii</em> Diesing, 1850 (as <em>Cephalothrix oerstedii</em>) are<br>declared nomenclaturally unavailable.</p> 2019-06-07T06:01:17+00:00 ##submission.copyrightStatement## Environmental conditions limit the distribution of Lepidurus arcticus (Branchiopoda, Notostraca) in lakes on the Hardangervidda mountain plateau, Southern Norway 2019-10-18T10:18:58+00:00 Tore Qvenild Trygve Hesthagen <p>The Arctic tadpole shrimp <em>Lepidurus arcticus</em> has a circumpolar distribution where the Hardangervidda mountain plateau in Norway marks its southernmost limit. Within this area, we searched for <em>L. arcticus</em> in 238 lakes in 27 catchments. On Hardangervidda, the distribution pattern of <em>L. arcticus</em> is highly skewed. In the 16 catchments located in the central and eastern parts, <em>L. arcticus</em> 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 <em>L. arcticus</em> (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<sup>-1</sup>, respectively. In the lakes in the central and eastern areas hosting <em>L. arcticus</em> (N=95), the mean value was slightly higher (1.67±1.14 mg L<sup>-1</sup>). The combination of low water temperature, a short growing season and dilute water low in calcium may explain the near total absence of <em>L. arcticus</em> in the western part of Hardangervidda. All lakes contain brown trout<em> Salmo trutta</em>, and as <em>L. arcticus</em> 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 <em>L. arcticus, </em>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 <em>L. arcticus</em> is common, their occurrence increased significantly with lake size, being found in 54% of the lakes &lt;1.0 km<sup>2</sup>, as opposed to 97% in the bigger lakes. Furthermore, <em>L. arcticus</em> 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 <em>L. arcticus</em> on Hardangervidda. The projected increase in temperature towards the end of this century may exterminate <em>L. arcticus</em> from the lower parts of Hardangervidda, especially in the most shallow lakes. Many of the lakes have water quality with pH &lt;6.0 and calcium concentration &lt;1.0 mg L<sup>-1</sup>. In such lakes <em>L. arcticus</em> is living on the edge of its survival, and the projected increase in precipitation may dilute the waters even further, pushing <em>L. arcticus</em> nearer to its extinction threshold.</p> 2019-07-11T15:34:22+00:00 ##submission.copyrightStatement## Paradulichia spinifera Gurjanova, 1946 (Amphipoda, Dulichiidae), a valid species? 2019-10-18T10:18:58+00:00 Per-Otto Johansen Wim Vader <p>Examination of <em>Paradulichia</em>-material collected from the Barents Sea during the Mareano cruises<br>indicated that there are clear morphological differences between <em>Paradulichia typica</em> Boeck, 1871<br>from the Hardangerfjord, W. Norway and <em>Paradulichia spinifera</em> Gurjanova, 1946 from the Arctic.<br>Based on our material and the original descriptions, these differences are the acute ventral parts of the<br>body segments, the triangularly shaped coxal plates 3 and 4, the shape and length of the mandible palp<br>articles, the long merus of pereopods 5 and 6, the elongate telson and the 2-articulate rami of uropod 2.</p> 2019-07-11T15:45:44+00:00 ##submission.copyrightStatement## Teleostei, Scophthalmidae: four-spot megrim spotted in Norwegian waters 2019-10-18T10:19:01+00:00 Rupert Wienerroither Otte Bjelland Gjertrud Jensen Anne Kari Sveistrup <p>The flatfish four-spot megrim (<em>Lepidorhombus boscii</em>) was registered in Norwegian waters, both in&nbsp;trawl catches and video observations. The records represent a considerable northward extension of&nbsp;the species. Specimens of up to 49 cm were measured, representing also a new maximum size for this&nbsp;species. The number of registrations has increased within the last years, indicating that the species got&nbsp;more common in this area.</p> 2019-03-21T07:51:46+00:00 ##submission.copyrightStatement##