The effect of catch-and-release angling at high water temperatures on behaviour and survival of Atlantic salmon Salmo salar during spawning migration.

In this study, behaviour and survival following catch-and-release (C&R) angling was investigated in wild Atlantic salmon Salmo salar (n = 75) angled on sport fishing gear in the River Otra in southern Norway at water temperatures of 16.3-21.1 °C. Salmo salar were tagged externally with radio transmitters and immediately released back into the river to simulate a realistic C&R situation. The majority of S. salar (91%) survived C&R. Most S. salar that were present in the River Otra during the spawning period 3-4 months later were located at known spawning grounds. Downstream movements (median furthest position: 0.5 km, range: 0.1-11.0 km) during the first 4 days after release were recorded for 72% of S. salar, presumably stress-induced fallback associated with C&R. Individuals that fell back spent a median of 15 days before commencing their first upstream movement after release, and 34 days before they returned to or were located above their release site. Mortality appeared to be somewhat elevated at the higher end of the temperature range (14% at 18-21 °C), although sample sizes were low. In conclusion, C&R at water temperatures up to 18 °C had small behavioural consequences and was associated with low mortality (7%). Nevertheless, low levels of mortality occur due to C&R angling and these losses should be accounted for by management authorities in rivers where C&R is practised. Refinement of best practices for C&R may help to reduce mortality, particularly at warmer temperatures.

Morphological differences in parr of Atlantic salmon Salmo salar from three regions in Norway.

Morphological characters were compared in parr (total length 33-166 mm) of Atlantic salmon Salmo salar sampled from eight wild populations in three regions, three in northern, two in the middle and three in southern Norway, covering a distance of 1700 km (from 70° N to 58° N). On the basis of morphological characters 94·6% of the individuals were correctly classified into the three regions. Discrimination between populations within these three regions also had a high degree of correct classification (89·0-95·8%). Principle component analysis identified largest differences to be in head characters, notably eye diameter and jawbone, with the smallest diameter and head size among the northernmost populations. Fish from the southern rivers had a deeper body form whereas fish from the middle region had larger heads and pectoral fins. This illustrates that S. salar already in the early parr stage has morphological traits, which can be used in discrimination between regions and populations and that these differences are discernible in spite of the volume of escaped farmed fish spawning in Norwegian rivers during the past 30 years.

Pre-winter lipid stores in brown trout Salmo trutta along altitudinal and latitudinal gradients.

Pre-winter lipid stores of brown trout Salmo trutta L. parr were compared along altitudinal (0-920 m a.s.l.) and latitudinal (58-71° N) gradients. There were increases in lipid content (size adjusted to common lipid-free dry mass of 2·0 g, corresponding to fresh mass of 10 g) with both increasing altitude and latitude. Mean size-adjusted lipid content for S. trutta in high altitude rivers was 60% higher than at low altitude (0·29 and 0·18 g, respectively). Mean size-adjusted lipid content for S. trutta in northern rivers was 30% higher compared to that in southern rivers (0·30 and 0·23 g, respectively). There was a marked between-river variation in mean lipid storage, probably reflecting different strategies or opportunities for the pre-winter acquisition of lipid both locally within rivers and between different populations. This study shows that temperature or winter length, not latitudinal covariates such as annual light regime, governs lipid storage patterns in juvenile salmonids.

Pre-winter lipid stores in young-of-year Atlantic salmon along a north-south gradient.

The pre-winter lipid stores of young-of-the-year (YOY, age 0 year) Atlantic salmon Salmo salar were analysed along a north-south gradient from c. 71 to 58 degrees N, with winter conditions ranging from >200 days of ice cover to no ice. The rivers sampled in Northern Norway represent some of the most northerly S. salar rivers. There was an increase in lipid content with increasing latitude, and mean lipid content (size adjusted to common mass) for YOY in northern rivers were almost three times higher: 0.035 g compared to 0.013 g in southern rivers. The relationship was not sensitive to variation in sampling time or variation in YOY body size. The lipid stores, however, varied markedly between rivers and also between neighbouring rivers, indicating different strategies or opportunities for pre-winter lipid storage both at latitudinal and local scales.

Man and polar bear in Svalbard: a solvable ecological conflict?

The objective of this study is twofold. First, it is to assess the nature and magnitude of the polar bear-human conflict with respect to injuries to man and bear. Second, a major concern has been to minimize injurious interactions in order to safeguard the people who live and work in the Arctic, and, at the same time, secure the future of the polar bear in one of the last relatively unspoiled habitats on earth for big carnivores. From 1971 to 1995, approximately 80 bears were involved in serious bear-human interactions. Of these, 77 bears were killed and 3 escaped after having injured people. During the same period, 10 people were injured, 4 of them fatally, in 7 separate interactions, each involving a single bear. None of the victims carried an appropriate firearm. The circumstances leading up to the confrontations give strong reasons for supposing that the majority of the attacks were predatory in nature. Seven of the injured, including the four who were killed, sustained bites to the head and neck. Correct use of firearms could probably have prevented all the fatalities. However, the keeping and use of firearms caused two accidental deaths in the same period. We conclude that alertness, the absence of attractants (food, garbage), and appropriate bear repellents to secure field camps are important items in preventing conflicts and should always be available. However, as a last but indispensable resort, a firearm (rifle or shotgun) carried by an experienced user is the only safe precaution for avoiding injuries in polar bear country. Killing a bear on the rare occasions when humans are in danger presents no threat to the bear population. With regard to physical injury to people, the problem is a minor one. Bears have a dual impact on everyday life in the Svalbard settlements. While there is some anxiety related to the presence of bears, the polar bear is a source of breathtaking adventure highly valued by both residents and visitors.

[Treatment of chronic subacromial pain syndrome using a sling]. / Slyngebehandling ved kronisk subakromialt smertesyndrom.

The subacromial impingement syndrome is a condition which affects the quality of daily living as well as working capacity. It has been claimed that this condition can be treated by exercising the shoulder with the arm suspended in a sling. We have treated 32 patients with this method. The results were evaluated with regard to relief of pain and return to previous work. After a follow-up of from six to 20 months, only two of the patients experienced so much relief of pain that they could return to work. We conclude that sling treatment is not the way to deal with this condition.

[Acromion resection for shoulder impingement syndrome. Results after an open and a percutaneous surgical method]. / Acromionreseksjon for inneklemmingssyndrom i skulderen. Resultater etter åpen og perkutan operasjonsmetode.

Anterior acromioplasty as described by Neer has been an effective procedure for shoulder impingement syndrome. Artroscopic acromioplasty is regarded as a technically demanding procedure. Since 1988 we have developed a closed percutaneous acromioplasty using motorized instruments. The purpose of this randomised clinical trial was to compare the results of open and closed percutaneous acromioplasty. We found a significant improvement in shoulder score, but no differences between the group treated with the open procedure and the group treated with the closed procedure.

[Enterobacter cloacae infections at the Regional Hospital in Tromsø]. / Enterobacter cloacae-infeksjoner ved Regionsykehuset i Tromsø.

Enterobacter cloacae was isolated from 69 patients hospitalized at the University Hospital of Tromsø, Norway, during a period of 18 months. The total lethality was 11.6% (8/69) and death occurred most often in patients with a serious underlying condition. Death due to septicaemia occurred in 4/10 patients. Multiple beta-lactam resistant strains were present in 15 patients and were associated with septicaemiae (7/10, p less than 0.0005). Cephalosporin treatment had been given to every third patient (24/69), and nearly half of them (10/24) were infected by multiple beta-lactam resistant E cloacae. E cloacae occurred mainly as a nosocomial infection, since more than 70% of all patients infected had been treated by an invasive procedure prior to isolation of the bacterium. A high number of E cloacae strains were from operation wounds, especially among patients at the Department of Surgery (22/30). At this Department, the total number of E cloacae, and especially the number of multiresistant strains, was markedly reduced during restricted use of cefalosporins.