Thesis (M.C.S.)--Regent College, Vancouver, BC, 2001. / Abstract and vita. Includes bibliographical references (leaves [108]-119).

Thesis (M.A.(St.Art.Hist.)) -- University of Adelaide, Master of Arts (Studies in Art History), School of History and Politics, Discipline of History, 2005. / Coursework. 2 December 2005. Bibliography: leaves 74-91.

Thesis (M.C.S.)--Regent College, Vancouver, BC, 2001. / Abstract and vita. Includes bibliographical references (leaves [108]-119).

Thesis (M.C.S.)--Regent College, Vancouver, BC, 2001. / Abstract and vita. Includes bibliographical references (leaves [108]-119).

Rising temperatures, because of climate change, will have major consequences for the world's fish populations, including the Atlantic salmon Salmo salar L. The greatest temperature changes are expected to occur during winter, which will affect S. salar since the eggs are developing during this time of year. Several studies have shown that elevated temperatures during embryogenesis cause morphological changes, in S. Salar, that are shown in later life stages. Some of these studies indicate that eggs incubated at high temperatures should generate parr with deeper bodies. To investigate whether high temperatures during the egg stage cause changes in body shape, parr from normal and high temperature incubated eggs, referred to as as “cold” and “warm” fish, respectively, were examined. A box-truss of euclidean distances between 10 landmarks on the fish body and a discriminant function analysis (DFA) was used to determine which of the distances best discriminated between the two groups. The test showed a significant discrimination between cold and warm parr regarding body shape where cold parr had greater heads and warm parr were deeper over the tail region and showed greater distances between the pelvic fin and the front attachment of the anal fin. 67,3 % of all parr where correctly classified by the test. These results support those notions that indicates that the incubation temperature is important for the morphological development of S. salar although it does not support the hypothesis. / Stigande temperaturer, till följd av klimatförändringar kommer att få stora konsekvenser för jordens fiskpopulationer, däribland atlantlaxen Salmo. Salar L. Störst temperaturförändringar väntas ske vintertid, vilket kommer att påverka S. Salar som övervintrar sin rom. Flera studier har visat att förhöjda temperaturer under embryogenesen ger upphov till morfologiska förändringar hos S. Salar under senare livsstadier. Några studier pekar mot att högtemperaturinkuberad rom torde ge upphov till parr med djupare kroppsform. För att undersöka om höga temperaturer under romstadiet ger upphov till förändringar beträffande kroppsform undersöktes parr (kalla resp. varma) från normal-  respektive högtemperaturinkuberad rom. Med hjälp av ett rutnät / box-truss mättes avstånd mellan 10 landmärken på fiskkroppen och en discriminant function analysis DFA användes för att avgöra vilket av avstånden som bäst diskriminerade mellan de båda grupperna. Testet visade en signifikant diskriminering mellan kalla och varma parr beträffande kroppsform där kalla parr hade större huvudmått och varma parr hade djupare mått över stjärtspolen och längre mått mellan analfenans främre infästning och bukfenan.  67,3 % av all parr förutspåddes tillhöra rätt grupp. Dessa resultat är i linje med den litteratur som anger att inkuberingstemperaturen har betydelse för den morfologiska utvecklingen hos S. Salar däremot stödjer de inte den angivna hypotesen.

The critical swimming speed (Ucrit) of rainbow trout parr (Oncorhynchus mykiss) and three life stages of Galaxias maculatus, larval (whitebait), postlarval inanga and adult inanga, were tested at temperatures from 5oC to 25oC. All fish were swum at their acclimation temperature under normoxic conditions to determine the optimal aerobic exercise temperature. To determine whether acclimation affected swimming ability, trout parr acclimated to either 10oC or 20oC were swum at 20oC and 10oC, respectively. The potential effect of mild hypoxia (75% saturation) on trout parr and whitebait was also examined at 10oC, 15oC and 20oC, and also tested separately and in combination were the effects of mild hypoxia and severe anaemia on the prolonged swimming ability of trout smolts at temperatures from 10oC to 20oC. For all trout experiments, blood samples were taken from non-exercised and exercised fish by acute caudal venepuncture to determine haematological responses to both acclimation and exercise. Under normoxic conditions, Ucrit max for trout parr (7.0 0.5 cm fork length) was calculated to be 5.8 body lengths per second (BL s-1) at 15.1oC, but declined at lower and higher temperatures. This result implies that swimming performance was limited by temperature below 15oC, whereas performance at higher temperatures was limited by oxygen availability. In support of this hypothesis, mild hypoxia (75% saturation) had no effect at 10oC or 15oC but caused a significant reduction in Ucrit at 20oC. However, fish acclimated at 20oC showed an adaptive elevation in oxygen carrying capacity due to an increase in mean erythrocyte volume and haemoglobin content. Furthermore, acclimation to 20oC improved warm water swimming performance. Trout parr acclimated to 10oC performed significantly worse than fish acclimated to 20oC when swum at 20oC. However, trout parr acclimated to 20oC performed as well as fish acclimated to 10oC when swum at 10oC. Following exercise, haematocrit was elevated under both normoxic and hypoxic conditions. However, the primary cause of this apparent increase in oxygen carrying capacity was splenic release of erythrocytes under normoxic conditions, whereas stress-induced erythrocytic swelling contributed to the observed increase in hypoxia. This contrasting response was most pronounced at 10oC. Larval whitebait (4.7 - 5.0 cm total length (TL)) also showed a temperature dependence of prolonged swimming ability with Ucrit max calculated to be 5.1 BL s-1 at 17.7oC. Hypoxia significantly reduced Ucrit at 15oC and 20oC, lowering the optimal aerobic temperature to 13.9oC and reducing Ucrit to 4.2 BL s-1. Mild hypoxia therefore had a more pronounced impact on inanga whitebait than trout. Postlarval inanga (3.9 - 4.0 cm TL) performed poorly at higher temperatures with Ucrit max of 5.6 BL s-1 at 9.4oC indicating an ontogenetic change in swimming ability, possibly resulting from a developmental shift in red muscle kinetics or a greater dependence on anaerobic muscle. Adult inanga (5.5 - 6.8 cm TL) prolonged swimming ability showed similar temperature dependence to that of inanga whitebait but lower relative swimming speeds due to their larger size. The dramatic decline in performance exhibited by juveniles at warmer temperatures was not apparent in adults. Ucrit max for adults was 4.0 BL s-1 at 18.3oC. The critical swimming speed of trout smolts, subjected to mild hypoxia (6.8 mg

Zugl.: Regensburg, Univ., Diss., 2009

Abstract This study investigated the ecophysiology of one of the world's northernmost Atlantic salmon (Salmo salar L.) stocks in the River Teno. The juvenile years of salmon of same genetic background were studied in the wild and in the hatchery conditions. In addition, the maternal size effect on reproduction was studied in wild females. Benefit of body size was not only quantitative but also qualitative in reproduction success of the wild female salmon in the River Teno. Total number of eggs and energy content of eggs were higher in big females than in smaller ones. In the hatchery, under natural day length and water temperature conditions, the growth rate, liver glycogen content and condition factor of the parr was higher than in the wild. The liver glycogen content of the hatchery-reared parr increased throughout the growing season and decreased during winter, whereas that of the wild parr was the lowest in summer, and stayed relative stable from September to May. The observed differences in annual fluctuation in liver glycogen content may reflect the differences in carbohydrate content of feed and in behaviour between the hatchery and wild. Overall, the hatchery-reared juveniles maturated and smoltificated 1–2 years earlier than the wild fish. The mean age of wild precocious males was 3 years and that of wild smolts 4 years. However, there was considerable variation in the age of precocious males (1–6 yr) and smolts (2–8 yr) in the wild. The maturing and smolting juvenile age groups were restricted to two (1–2 yr and 2–3 yr, respectively) in the hatchery. In June, the hypo-osmoregulatory ability of hatchery smolts was developed parallel to the wild smolts. Some differences in physiological parameters between different smolt groups could be observed in the wild and between hatchery-reared and wild smolts indicating that completing of smolting process varies to some extent under different conditions. However, the hatchery-reared smolts showed higher levels of fin damage and body energy stores than the wild smolts. As the hatchery practices should aim at controlling the quantity and quality of the juvenile salmon in production, the environmental conditions governing the physiological development of the juvenile fish should be taken into account. Hatchery practices should be planned so that the seasonal timing of smolting would follow the wild fish as close as possible.

Abstract Long-term monitoring of the wild salmon (Salmo salar L.) stock of the Simojoki river and the stocked hatchery-reared salmon parr and smolts has provided a considerable amount of information on the development of the stock and factors affecting it. Data on the relationships between wild and reared salmon were collected by tagging and trapping both smolts and adult salmon having either a wild or reared background. The tag recapture rate of wild smolts was about twice as high as that of smolts stocked as two-year-olds and slightly greater than for smolts stocked as parr. When survival was measured in relation to the smolt size, the difference between the wild and reared smolts was even greater, and it seemed to be emphasized in years with a low survival rate. The difference observed between the wild and reared salmon in the smolt phase generally disappeared in the adult phase. When adult salmon returned to the river to spawn the difference in the timing of the ascent depended more on the age or sex of the salmon, and less on their origin. Similarly, the survival of adult salmon in the river before or after spawning and later after returning to the sea depended on the sex and age of the fish. The origin of fish affected their behaviour, the reared salmon wandering more than wild adults before settling down into spawning areas. When the yield of wild and reared smolts as returning adults was compared, the wild smolts gave the best results, although the survival from smolt to adult was low in all smolt groups, probably due to the high fishing pressure in the sea. The smolts stocked as parr and those stocked as two-year-old fish were similar in this respect. The former group gave better results if the yield was measured as the number of returning multi-sea-winter adults, while the latter group gave better results if one-sea-winter grilse were also included in the yield. The low yield of adult salmon from stocking and the generally low survival of smolt groups irrespective of their origin emphasises the importance of fishing regulations as a tool in the maintenance or enhancement of naturally reproducing salmon stocks. However, despite the low profitability of stocking, it probably safeguarded the existence of the wild Simojoki salmon stock during its critical phase in the early 1990s. At that time the fishing regulations were not strict enough to prevent the alarming decrease in the salmon stock, and the adult spawners produced by stocking of young salmon may have had a relatively higher value than their number suggests.

Egg stocking in rivers and streams is a common measure to support and re-introduce salmonid populations. To ensure the success of egg stocking programs, knowledge of the early life stages of juveniles including dispersal ability and habitat preferences of fry is a prerequisite. This study was conducted to investigate downstream dispersal patterns and habitat use of young of the year brown trout in a mid-sized, channelized, boreal river in Sweden. Eyed trout eggs were stocked in February of 2021. During August of the same year, 2-3 months after emergence, trout were sampled by electrofishing within 1 km downstream of the stocking sites and each individual point of capture was recorded by GPS. In addition, data on riverbank slope, shoreline irregularity, stream bed substrate, water velocity and water depth were collected for each of the sampling sections. The results showed that trout fry were distributed throughout the 1 km long sampled sections and that the density of fry did not increase towards the stocking points. The observed variation in the distribution of trout fry was best explained by the riverbank slope. Approximately twice as high fry densities were found in reaches with gentle compared to medium and steep bank slopes. The differences are suggested to be an effect of 1) stream marginal water velocity differences during high flows affecting fry occupancy, and 2) that gentle slopes were often accompanied by shallow water, preferred by fry. These findings may provide helpful knowledge for fisheries managers to optimize the outcome of egg stocking and river restoration activities regarding fry recruitment. / Romutsättning i vattendrag är en vanlig åtgärd för att stärka och återetablera populationer av laxartade fiskar. För att lyckas med romutsättningar krävs kunskap om ynglens spridningsförmåga och habitatpreferenser. Denna studie genomfördes för att undersöka spridningsmönster och habitatval av ensomrig öring i en medelstor kanaliserad älv i Sverige. Ögonpunktad rom sattes ut i februari 2021. Under augusti samma år, 2-3 månader efter att ynglen lämnat lekgruset elfiskades 1 km långa sträckor direkt nedströms utsättningsplatserna. De fångade individernas position registrerades med GPS. Data över strandkantens lutning, strandzonens flikighet, bottensubstrat, vattenhastighet och djup samlades in för varje elfiskesträcka. Resultatet visade att öringyngel spridit sig över hela de 1 km långa elfiskesträckorna, och att tätheterna av yngel inte ökade med minskat avstånd till utsättningspunkterna. Den observerade variationen i fördelningen av öringyngel förklarades bäst av strandkantens lutning. Ungefär dubbelt så hög täthet av yngel förekom i sträckor med flack jämfört med medel och brant lutning. Skillnaderna föreslås vara en effekt av 1) skillnader i vattenhastighet under höga vattenflöden som påverkar ynglens möjligheter till att bibehålla sin position i habitatet, och 2) att flack lutning av strandkanten ofta åtföljdes av grunt vatten vilket föredras av yngel. Dessa upptäckter kan bidra med värdefull kunskap för att optimera romutsättningar och restaureringar i avseende på rekrytering av årsyngel.