The distribution limit of the common tick, Ixodes ricinus, and some associated pathogens in north-western Europe.

In north-western Europe, the common tick, Ixodes ricinus, is widely established, its distribution appears to be increasing and the spread of tick-borne diseases is of increasing concern. The project 'Flått i Nord' (Ticks in northern Norway) commenced in spring 2009 with the intention of studying the tick's distribution and that of its pathogens in northern Norway. Several methods were used: cloth-dragging, collecting from trapped small mammals, and collecting from pets. Since 2010, the occurrence of ticks in the region of northern Norway was determined directly by cloth-dragging 167 times in 109 separate locations between the latitudes of 64 °N and 70 °N (included seven locations in the northern part of Trøndelag County). The northernmost location of a permanent I. ricinus population was found to be Nordøyvågen (66.2204 °N, 12.59 °E) on the Island of Dønna. In a sample of 518 nymphal and adult ticks, the Borrelia prevalence collected close to this distribution limit varied but was low (1-15 %) compared with the locations in Trøndelag, south of the study area (15-27 %). Five specimens (1 %) were positive for Rickettsia helvetica. The length of the vegetation growing season (GSL) can be used as an approximate index for the presence of established populations of I. ricinus. The present study suggests that the threshold GSL for tick establishment is about 170 days, because the median GSL from 1991 to 2015 was 174-184 days at sites with permanent tick populations, showing a clear increase compared with the period 1961-1990. This apparent manifestation of climate change could explain the northward extension of the range of I. ricinus.

Records of ocean sunfish Mola mola along the Norwegian coast spanning two centuries, 1801-2015.

Records of the ocean sunfish Mola mola along the Norwegian coast were compiled from all possible sources: literature, media, databases and museums. A total of 216 records were found between 1801 and 2015. They were distributed along the whole coast, except for the most north-eastern part. Nearly all years with more than five records were after 2000, with 1985 as the only exception and with a maximum of 23 records in 2014. Most, 92·4%, were from July to December. Records from before 1979 were more incidental and random and no sunfish were recorded in 54 separate years between 1879 and 2015. The northernmost record was from 70° 44' N in December 1881. No relationship between year and latitude was found. Forty-four per cent of the records were of sunfish caught in fishing gear, 27% were found stranded and 30% were observed alive at sea. A trend of a decrease in numbers of observations of living individuals and an increase in numbers of strandings as dead individuals as autumn progressed was found. Geographical differences in the three categories of observation were also found. Among the specimens whose size was recorded, most were small, <30 kg and 70 cm in total length. Only 10 were heavier than 100 kg, all these were from before 1960. Annual numbers correlated weakly with sea temperatures. This was supported by a weak negative correlation with the North Atlantic Oscillation (NAO) index, because the majority of years since 2000 had a negative NAO.

Agonistic behaviour and dominance relations of captive arctic foxes (Alopex lagopus) in Svalbard.

Agonistic behaviour and dominance relations were studied in three groups of arctic foxes (Alopex lagopus) on the western coast of Svalbard (79°N): (1) Five 'tame' foxes (3♂♂, 2♀♀) kept in captivity for 9-26 months, (2) twenty-two 'wild' foxes (11♂♂, 11♀♀) kept in captivity for 4 days to 3 weeks, and (3) free-living foxes. Experiments were started by introducing two foxes (n = 74 dyads) into a large enclosure (360 m(2)), scoring winners and losers in a competition for food, calculating a dominance index (DI), and observing the frequency of 12 behaviours. DI was correlated with body size as measured by the length of a front foot, but not with body weight. Males dominated females more frequently than vice versa (P < 0.06). Tame foxes were more playful and less aggressive than wild foxes. Fighting was mostly restricted to chasing and following, and no injuries were seen. When considering all 12 behaviours no significant difference was found between winners and losers, males and females, larger and smaller, heavier and lighter foxes. However, winners were more frequently following and chasing (i.e. offensive), while losers more frequently behaved submissively. Ignoring (dominant) or evading (subordinate) behaviours were frequent, and no distinct display signalling high social status was found.