The aim of the thesis is to analyse the preconditions for increasedsalmon angling in the remaining wild salmon rivers in Upper Norrland in northernSweden, as well as to evaluate the present and possible future impacts on the localeconomy. It includes the identification of the internal and external conditions, in what ishere called the Salmon Utilisation Landscape, that influence the present use as well asfuture development of the Baltic salmon as a resource in angling. The empirical materialsderive from two mail surveys, 1) a survey of anglers in the River Byske and 2) a jointNordic survey on the economic value of recreational fishing.Interest in recreational fishing is widespread in Sweden. About 35 % of adultSwedes fish for recreation. Recreational fishery and angling can be seen as one expressionof the urbanised society's need for contact with nature and outdoor recreation. Salmonangling is one part of recreational fishery. Salmon are considered by many to be the 'biggame' of angling. Salmon anglers are often the most devoted kind of anglers, investingconsiderable resources into this leisure activity. The subgroup of Swedish salmon anglingspecialists is estimated at 10-30,000 persons. The wider category of Active River anglersconsists of approximately 170,000 persons.Salmon fishing in the River Byske has turned out to be representative of salmonangling in Upper Norrland, comparable with other high-class Scandinavian salmon rivers.The growing proportion of remote anglers in the 1990s indicates that the Byske hasbecome a rather specialised angling water. The groups of Fishing tourists and Home fishersmake up two distinctive categories. Fishing tourists fish more intensively, have higher dailyexpenditures and show higher consumer surplus. They fish the river almost entirely forsalmon in. On the other hand, Home fishers to a large extent claim the right to fish fordecent prices and without any particular restrictions. During the 1990s, the average annualincome to the local economy of Byske river valley derived from salmon angling fishingtourism was about 850,000 SEK.Many river habitats have been depleted during the 20th century and many salmonstocks were exterminated by severe degeneration factors linked to industrialisation. To thisis added the over-fishing on wild stocks of salmon and the mortality syndrome, M74. Theavailable estimates of the potential production of wild salmon smolt in Upper Norrlandaggregates close to 1.2 million. This can be converted to an angling activity of some250,000 fishing days.On the basis of the prevailing cost level, the potential angling activity in UpperNorrland would amount to a direct annual turnover of 75 million SEK, however theimpact caused by fishing tourism is likely to remain within the interval of 10 - 30 millionSEK. The Active River anglers' average willingness to pay for annual access to a salmon andsea trout scenario was 1,100 SEK per capita. There is a widespread attitude among manyanglers that fishing should be accessible for all and prices should be kept low. In theNordic context such opinions are especially evident among Swedish anglers in general, butless frequent among devoted salmon anglers. / digitalisering@umu

This thesis evaluates the adaptive significance of annual cycles on the migratory behaviour of Baltic salmon (Salmo salar L.). The studies have included field experiments as well as laboratory studies gf maturity and migratory behaviour patterns of smolts and postsmolts mainly from the Angerman river population. Contrasting to the phenotypical elasticity in life-history traits, Baltic salmon was found to have a rather strict temporal organization of their annual behavioural patterns. Two year old smolted Baltic salmon showed drastic differences in migratory behaviour when compared in tanks containing either fresh or brackish water. Freshwater kept fish showed an annual cycle where downstream displacement in the upper water column was followed by a stationary behaviour, indicating a readaption to a freshwater life. Fish in brackish water behaved as a migratory fish throughout tne study. Baltic salmon also showed differences in maturation patterns in fresh and brackish water. Three summer old males detained in freshwater all matured sexually the following autumn. If transferred to sea and kept in net- pens a low proportion matured, mainly previously matured males. Furthermore there was a size- dependent relationship of sexual rematuration. Many small previously matured males did not migrate, similarly small previolusly matured males were unable to respond to shifts in the environment. With larger size the alternatives of sexual maturation and high growth rate wi more related to the environmental conditions the fish experienced. A hypothesis has been tested assuming that Baltic salmon migration is influenced by an annual time program. According to the hypothesis the migratory distance covered in the Baltic should be a result of a migratory activity sequence rather than a definite goal orientation. Fish detained before release generally showed a shorter distance between release point and area of recapture compared to fish released at normal time of smoltrun. The migratory distance appeared to be inversly related to the period of delay before release. A seasonal difference in migratory propensity was recorded. An instantaneous mortality curve for Baltic salmon during seaward migration and early sea-phase was estimated based on recapture data on sequentially related fish. The weekly mortality rate decreased from an initial mean of 271 during onset of migration, to 3.51 in mean during autumn. The high risk of mortality during the first part of migration indicated that strong selective forces act on a precise seasonal timing of migration. / <p>Diss. (sammanfattning) Umeå : Umeå universitet, 1988, härtill 5 uppsatser</p> / digitalisering@umu

This thesis deals with important factors that affect the temporal organization of emergence and early survival of Baltic salmon (Salmo salar L.). The study population was obtained from the Norrfors hatchery (63°50'N,20°05'E), Umeälven (Ume river) in Northern Sweden. The main objectives of the thesis has been to study; a: the effect of female and egg characteristics on embryonic survival, b: the effect of egg size, temperature and photoperiod on the emergence pattern and c: the impact of early or late emergence on survival in relation to predation and limited territorial space. The main results are summarized as follows: (1) Fecundity and egg size increased with increasing weight of females. No effect of female size were found on egg colour. Longer impoundment and later stripping increase egg colour. Egg mortality was not correlated with egg colour. Stripping date was found to have the strongest effect on mortality. (2) Egg size had no effect on the timing of emergence but fry of different egg size emerged synchronously. Fry from large eggs left the gravel as heavier fry and with a larger proportion of yolk left compared to fry from small eggs. (3) The number of days and number of degree days from hatching to 50% emergence decreased exponentially with increasing temperature. Synchronization of emergence increased with increasing temperature. Fry emerged with more yolk at 12 °C compared to 6 °C. (4) Eggs kept in a LD 16:8 light regime hatched mainly during the light period, while eggs kept in constant darkness hatched continously over a 24 hour period. Alevins kept at different light regimes (light&gt;4h) from hatching until emergence left the gravel during the dark period. Daylength had no effect on the annual onset of emergence. (5) In a laboratory stream channel, predator presence at emergence increased mortality especially in early emerging fry. If the predator was introduced after completed emergence high mortality was noted among late emerging fry. The presence of fish predators and a limited territorial space for fry seemed to make early and late emergence hazardous and to favour a "peak" emergence. In the presence of a predator the fry changed their behaviour by reducing their swimming activity. / digitalisering@umu.se