Abstract The long-term monitoring programme for the River Teno Atlantic salmon (Salmo salar L.) stocks has covered the juvenile densities (25 yr) and the abundance and characteristics of the returning adults (31 yr). The feasibility of the programme was examined by studying the interrelationships between the yearly catches and juvenile salmon densities, performance and reliability of the electrofishing method, and the effects of fishing regulations on the salmon stocks. Finally, juvenile salmon abundances were related to the available fluvial habitat and reference levels were defined by using habitat models. Extensive seasonal variation in juvenile salmon density was apparent. The densities of fry and parr showed an increase from early summer towards late August and a subsequent decline towards the autumn. Long-term electrofishing monitoring is recommended to be carried out in as standardized a form as possible in order to reduce variations in catchability. Over the 25-year monitoring period, the abundance of parr (1+) increased in one sampling site cluster out of nine clusters and declined in one cluster. Fry densities increased in seven clusters. Juvenile densities exhibited considerable temporal and spatial variation. Similarly, the salmon catches varied extensively, and the numbers of 1-2SW salmon and previous spawners increased. The numbers of 1–2SW female salmon in the catches and the subsequent juvenile densities were significantly related, as regression models explained 19–44% of the variation in juvenile abundance. The juvenile monitoring allows evaluation of the relative spawner abundance in preceding years, confirming the information provided by catch statistics. Juvenile salmon densities explained 23–41% of the variation in subsequent 1–2SW salmon catches. Significant correlations were detected with a lag of one year between the subsequent sea-age groups of salmon in the catches. Thus, these relationships can be used for forecasting future salmon abundances. Large areas of high habitat quality in the River Teno system fail to meet their expected juvenile densities, and factors others than physical habitat characteristics, such as a lack of spawners, restrict the juvenile abundance. More than 50% of the permanent sampling sites where habitat would predict high densities (≥ 50 parr per 100 m2) had observed densities in the mid (10–49) or low density category (< 10). It was expected that the densities should increase after regulatory measures implemented in 1989–1990, but results indicate that the reference levels of parr densities have not been attained and the densities have not increased, whereas a general increase in salmon fry densities was detected. Nonetheless, the management measures have succeeded in maintaining the River Teno salmon stocks, which still today enable and support diversified fisheries.

Atlantic salmon (Salmo salar L.) has been domesticated since the 1960s and has undergone over 10 generations of artificial selection for economically important traits. As a result, domesticated salmon have diverged with respect to a number of phenotypic, genotypic and behavioural traits from their wild counterparts. Since the selection pressures that are present in the wild differ greatly from the ones that shape salmon under culture conditions, domesticated salmon stocks are considered to be maladapted to natural conditions. Despite strict regulations, insoluble issues pertaining to large-scale cage rearing of farmed fish mean that there is a continuous presence of farm escapees in the wild. Gene flow from escapees has been perceived as a factor in the decline of wild populations, suggested to occur through disruption of local adaptation. This study aims to improve understanding of the genetic differences between wild and domesticated stocks by comparing the transcriptomes of Figgjo (wild) and Mowi (domesticated) strains. A series of common garden experiments have been performed, utilizing pure and reciprocal hybrid crosses of the wild and domesticated stocks, reared under two different conditions and sampled at four time points and three distinct life stages (embryo, sac-fry and feeding fry). Microarray interrogations were performed employing a 44K custom microarray design to identify genes and gene pathways that are differentially expressed between the stocks. KEGG-based functional analyses have been implemented using different gene set enrichment packages, and dominance and additive parameters were calculated from normalized expression values to predict the mode of heritability of the genes identified as differentially expressed between stocks. Most biological functions represented in wild and domesticated crosses were consistent across life stages and environments. The transcriptomic differences detected between stocks in multiple developmental stages likely reflected adaptations to selection pressures differing between natural and aquaculture environments. Down-regulated environmental information processing and immune and nervous system functions in domesticated vs. wild fish may be due to local adaptation to captivity. These included reduced information acquisition and processing systems, altered stress responsiveness and changes in feeding behaviour. In line with the resource allocation theory of production trait animals, reduced immune function was coupled with increased expression of growth and development related pathways in domesticated salmon, compared to wild counterparts. Although there is support for this trade-off in all life-stages, resource allocation showed a shift over time; possibly reflecting variation in the utilization of energy sources during the transition from endogenous to exogenous feeding. Differences in cell communication and signalling pathways between wild and domesticated stocks, associated with organogenesis during the embryo stage, reflect sampling time and are indicative of altered organ development in response to domestication. Stress responses common across stocks included the down-regulation of cellular processes, including cell cycle and meiosis, and genetic information processing, such as replication and repair, transcription and translation pathways, probably reflecting the reallocation of energy resources away from growth and towards the restoration of homeostasis. Moreover, the mobilization of energy to cover the increased demands of maintaining homeostasis was indicated by the up-regulation of some metabolic pathways, mostly involved in energy, lipid and carbohydrate metabolism in response to stress. The analysis also revealed cross-specific stress responses, including indicators of a non-additive stress response in hybrid crosses. Most differentially expressed transcripts exhibited additive (31-59%) or maternal dominant (19-33%) inheritance patterns, although maternal over-dominance (23-26%) was also significant in the embryo stage. The mode of heritability of some immune transcripts was suggestive of maternal environmental influence having been affected by aquaculture. This study has demonstrated that biological functions affected by domestication include those associated with allocation of resources, involve reduction of information acquisition and processing systems and may lead to loss of local adaptation to wild conditions. Since such changes may affect key systems, such as immunity and responsiveness to stress, they can potentially have serious negative consequences under natural conditions. Transcriptomic differences observed between wild and domesticated stocks primarily exhibited additive and maternal dominant inheritance modes. Since gene-flow from farmed fish can be frequent and primarily concerns farmed females, this suggests that introgression due to repeated large scale escape events has the capacity to significantly erode local adaptation.

Memoria para optar al Título Profesional de Ingeniero Agrónomo / El afrecho de soya (AS) ha sido utilizado como sustituto de la harina de pescado (HP) debido a su bajo precio, disponibilidad y propiedades nutricionales, pero su nivel de inclusión ha estado limitado debido a la presencia de factores anti-nutricionales. Varias alternativas han sido planteadas para reducir los niveles de estos compuestos (Polisacáridos no derivados del almidón (NSP), alfa-Galactosidos (GOS), saponinas, lectinas, etc.) una de ellas es el pre-tratamiento de la soya mediante Fermentación en Estado Sólido (SSF), sin embargo hay poca información disponible sobre los efectos del afrecho de soya fermentada (ASF) en alimentos para salmónidos, aun mas hay pocos estudios que hagan referencia al efecto que causan las fuentes proteicas vegetales en el intestino proximal.

Thesis (M. Sc. (Agriculture)) -- University of Limpopo, 2016 / Fish assemblages in relation to environmental variables within the Broederstroom and Debengeni Rivers were investigated. Both rivers were characterized by coarse substrates (pebble and gravel), temperatures below 20°C and moderate depth. Trout dominated fish assemblages in terms of numbers caught and was only distributed at higher altitude sites >1400 m (a.s.l). Coarse substrates, temperatures below 15°C, flow rate, depth and riparian cover were the variables shown important for the distribution of trout by multivariate analysis. The confinement of the trout to higher altitude and lack of optimal habitat variables at lower altitude sites contributed to the assertion that the area is marginal for trout distribution. It was therefore inferred that the marginality of the area is the possible explanation for trout failure to self-sustain its population, therefore dependent on the continuous restocks by the local hatchery. The continuous restocks of small size trout in the Broederstroom River prompted a subsequent study where trout’s impact on macroinvertebrate communities was evaluated through surveys and field experiments. The ability of small trout to utilize macroinvertebrates made them suitable candidates to evaluating their impact in the area. Aquatic invertebrates were found to be the main food source for the trout in the area. Taxa such as Gomphidae and Potamonautidae were the most frequent food items from the analyzed stomachs of trout. However, observations from both field surveys and experiments showed that trout is a weak regulator of macroinvertebrate diversity in the area, since there were no significant differences (ANOVA, P<0.05) in the diversity of invertebrates from trout invaded and uninvaded sites. Trout being a weak regulator of macroinvertebrate diversity in the area, it prompted surveys to the Ebenezer Dam to determine its competitive interactions with native predatory species. If the introduced species is a more efficient predator than the native predator species, it may affect changes in the structure of the habitat and food resource. Trout in the Ebenezer Dam was found to be selective to habitat variables whilst C. gariepinus was cosmopolitan to all habitat categories. The catfish also had a broader food preference than trout and the diversity of the food items was significantly different (ANOVA, P<0.05) between the two species. Unfortunately, the interspecific food overlap between trout and the catfish could not be determined in Ebenezer Dam, because of the small sample size of trout but food selection between vii them was evident. It was then concluded that the native catfish has a wider niche and it is a more efficient predator than the introduced trout. This observation contributed further to the assertion that the area is marginal for trout to thrive. Due to trout selection of habitat variables, it became prudent to carry out another study where the past climate and land use changes were analyzed to determine their effect on the habitat that could have affected the distribution of trout in the area. Future projections were also made to determine possible future impacts of climate change on the distribution of trout in the area. The effects of climate and land use change resulted in warmer water temperature, altered riparian cover and altered stream flow patterns. The changes could have influenced the confinement of trout to higher altitude catchments. The projected maximum temperatures by 2050 shows an increase from 2014 with a decline in precipitation. If these projections are to be the same for water temperature and flow regimes, coupled with current land uses in the area, they will continue to affect the distribution of trout negatively.

The brown trout (Salmo trutta) in Lake Siljan in the central of Sweden is one of the country´s few remaining populations of trout that migrates between large lakes and rivers. Because of antropogenic impact the number of mature individuals is small and the population is therefore supported by stocking of hatchery fish since several decades. Data have been collected using acoustic telemetry during 2018-2019 with the aim to study the population with the final goal to increase numbers of wild individuals. The results showed that most parts of Lake Siljan is utilized by both wild and hatchery trout. There is therefor no good measure to avoid wild bycatch by directing fishery of hatchery fish to specific geographic areas.  Measures like catch and release and low bag limits of wild fish will probably be more sufficient. The result also shows that the wild fish was most likely to home to the main source, River Österdalälven, and the tributary Hemulån for spawning. Protection of these areas is therefor highly motivated. The lake survival of the newly released 2-year-old hatchery smolt and the 4-years-old hatchery adults was low, 3 and 25 percent, respectively. The survival of wild and semidomestic adults was higher, 86 and 77 percent, respectively. This is another reason for increasing the number of reproducing wild individuals. Repeating of this study is important to get information of any possible variance between years in the utilization of the different areas in the Lake Siljan, the knowledge of spawning habitats and survival. This study has added some new and additional knowledge of a less studied field of the diverse life histories of the brown trout. / Öringen (Salmo trutta) i sjön Siljan i mellersta Sverige är en av landets få kvarvarande bestånd av öring som vandrar mellan ytstora sjöar och rinnande vatten.  Den självreproducerande delen av populationen är liten på grund av antropogen påverkan och har under flera decennier understötts med utsättning av odlade individer. Med akustisk telemetri har data samlats in under 2018-2019 i syftet att bygga kunskap som ska öka möjligheterna för att öka antalet av naturligt reproducerande individer. Resultaten visade att merparten av Siljans olika delområden nyttjades av både vilda och odlade individer utan någon uppdelning av dessa två delpopulationer. Förutsättningar för ett riktat fiske efter odlade individer i vissa geografiska delområden av Siljan föreligger därför inte. Fisket måste därav regleras gemensamt och likartat på över hela sjön. Resultaten visade också att vilda individer i huvudsak använder Österdalälven och biflödet Hemulån för reproduktion vilket motiverar ett ökat skydd för dessa områden. Överlevnaden av nyligen utsatta odlade 2-åriga smolt och 4-åriga adulter var låg, 3 respektive 25 %, vilket ger ytterligare skäl för arbetet med öka den självreproducerande andelen av populationen. Hos de frilevande adulta vilda och odlade individerna sågs en högre överlevnad, 86 respektive 77 %.  Upprepning av denna studie krävs för att detektera eventuell mellanårsvariation i nyttjandet av delområden, reproduktionslokaler samt överlevnad. Detta arbete har tillfört ny och kompletterande kunskap till en ringa studerad del av öringens många och diversa livshistorier.

Den anadroma öringen i Östersjöns avrinningsområde uppnår inte tillfredsställande status och uppskattningsvis upprätthålls ungefär hälften av populationerna med kompensationsodling. En av dem är Dalälvens anadroma öring som numer har sitt reproduktionsområde vid Älvkarleby, ca 10 km uppströms älvmynningen till Östersjön. Där finns även ett vattenkraftverk som innebär ett definitivt vandringshinder för Dalälvens migrerande arter. Vid Älvkarleby bedriver SLU Aqua forskning på öring och lax, samt ansvarar för kompensationsodlingen av Dalälvens anadroma öring. Tack vare det långvariga kompensationsodlingsprogrammet finns långa tidsserier innehållandes populationsdynamiska och strukturella data om populationen i Dalälven. I denna studie beskrivs långtidstrender i detta data, och med hjälp av statistiska metoder identifieras potentiella påverkansfaktorer. Resultaten visar att studieperioden kännetecknas av kraftiga populationsdynamiska fluktuationer, och temperatur identifierades som en stark påverkansfaktor. / Anadromous trout populations in the Baltic Sea area are in a less than optimal state and about half of the populations are maintained by hatchery-reared trout. One of the populations spawns near Älvkarleby of river Dalälven, about 10 km upstream of the estuary in the Baltic Sea. A hydroelectric dam located in the same area blocks the routes of migratory species. SLU Aqua operates the cultivation of trout native to river Dalälven and conducts research at the research center in Älvkarleby. Owing to the long-term cultivation in river Dalälven, long time-series containing population-specific data is available. Based on the collected data, this study describes long-term trends in the trout population native to river Dalälven and tries to identify potential factors effecting these by using statistical methods. The results show that the study period is characterized by large fluctuations in population dynamics, and that temperature is a major influencing factor.

Different strains of rainbow trout (Salmo gairdneri), Ten Sleep, Sand Creek, Beitey, Shepherd-of-the-Hills, New Zealand, Fish Lake- Desmet, Desmet, were compared for survival to the creel, growth and catchability after being stocked in a fluctuating 80 ha Utah reservoir . Fish were stocked in the spring and fall as fingerlings and monitored by creel censusing, gill netting and electrofishing. Fish were tagged with coded wire snout tags prior to stocking . An angler opinion survey was conducted to determine angler satisfaction with numbers and size of fish caught. Regardless of strain, spring stocking was superior to fall stocking in survival to the creel. In the spring 78 stocking the Ten Sleep strain had the highest survival to the creel (33.7 percent), followed in order by Shepherd-of-the-Hills (11.0 percent), Beitey (5.5 percent), Sand Creek (5.4 percent), New Zealand (4.1 percent), and Fish Lake-Desmet (2 .9 percent). In the spring 79 stocking the Shepherd-of-the- Hills strain had the highest survival to the creel (7 .6 percent), followed in order by the Sand Creek (7.3 percent) and the Ten Sleep (6.5 percent). Similar trends in survival were found in gill netting and electrofishing samples. Migration out of the reservoir was negligible for each strain. There were no strain differences in catchability by different methods (shore, boat) or gear (bait, artificial lure). Differences in growth between the fastest growing strains (Ten Sleep, Sand Creek) and the slowest growing strains (New Zealand, Fish Lake-Desmet) averaged as great as 16 mm in length and 43 g in weight. Differences in growth and survival among strains were great enough to span the range of angler satisfaction with numbers caught and size of fish caught from satisfactory to unsatisfactory. Therefore, strain selection can be a useful tool to improve fingerling stocking programs and manipulate the number of anglers who are satisfied with the angling experience.

[pt] O Sl 96, objeto de estudo da presente pesquisa, é uma poesia hebraica caracterizada como um louvor descritivo, enriquecido com o tema do reinado de YHWH. Em contraste com os três primeiros livros do Saltério (cf. Sl 3–89), o livro IV (cf. Sl 90–106) abre nova perspectiva, com um ideal teocrático, avultando a ação soberana de YHWH que age sem um regente humano. E o Sl 96 potencializa os elementos relacionados a esta ação de YHWH, apresentando-o como rei (cf. v. 10b), criador (cf. v. 5b) e juiz (cf. v. 13), e inaugurando o tema da sua soberania universal. Como unidade poética, o Sl 96 é estruturado em três seções que são corroboradas pelos elementos sintáticos, semânticos e estilísticos. Em cada seção há um sujeito expresso, propondo Israel como anunciador da boa nova da ação salvífica de YHWH (cf. v. 1-3), convidando as famílias dos povos a acercarem-se de YHWH e dançarem diante dele (cf. v. 7-9), e conclamando todo o cosmos a exultar de alegria com intensidade (cf. v. 11-12). Nesse convite a sujeitos distintos também se revela a universalidade de YHWH, mas sempre com a cuidadosa e enfática centralidade em YHWH, dada no emprego do sufixo de terceira pessoa, masculino, singular (i), no pronome pessoal הוּא e no Tetragrama Sagrado. Como louvor descritivo, o Sl 96 traduz um clima de intensa alegria, com o cântico novo cantado pelo povo que celebra os feitos de YHWH (cf. vv. 1-9) e o seu reinado (cf. v. 10), e com toda a criação que se agita de modo barulhento e festivo em razão da sua vinda (cf. vv. 11-13). / [en] Ps 96, object of study of the present research, is a Hebrew poetry characterized as a descriptive praise, enriched with the theme of the reign of YHWH. In contrast to the first three books of the Psalter (cf. Ps 3-89), book IV (cf. Ps 90-106) opens a new perspective, with a theocratic ideal, emphasizing the sovereign action of YHWH who acts without a human regenter. And the Ps 96 potentizes the elements related to this action of YHWH, presenting him as King (cf. v. 10b), creator (cf. v. 5b) and judge (cf. v. 13), and inaugurating the theme of his universal sovereignty. As a poetic unit, Ps 96 is structured into three sections which are corroborated by syntactic, semantic and stylistic elements. In each section there is an express subject, proposing Israel as announcer of the good news of the salvific action of YHWH (cf. v. 1-3), inviting the families of the people to approach YHWH and dance before him (cf. 7-9), and calling on the whole cosmos to exult joy with intensity (cf. v. 11-12). In this invitation to distinct subjects, the YHWH s universality is also revealed, although always with a careful and emphatic centrality in YHWH, given the use of the third-person suffix, masculine, singular (i), in the personal pronoun הוּא and in the Sacred Tetragrammaton. As a descriptive praise, Ps 96 expresses a mood of intense joy, with the new song being sung by the people who celebrate the achievements of YHWH (cf. vv. 1-9) and his reign (cf. v. 10), and with all of creation that stirs in a noisy and festive way because of his coming (cf. vv. 11-13).

[pt] O Sl 8, objeto de estudo da presente pesquisa, é uma poesia que descreve um aspecto da criação, como um louvor descritivo, emoldurado por um refrão corálico. O salmista se dirige a YHWH sempre na segunda pessoa, com exaltações inesgotáveis. Apresenta a figura do homem de maneira central no poema, sem no entanto ofuscar a centralidade de YHWH no que tange sua posição dentro do Sl 8. Enquanto unidade poética, o Sl 8 estrutura-se em duas seções (vv. 1-5 e vv. 6-10), que possuem nuances bem específicas e patentes devido a sua métrica. A primeira seção é iniciada com uma exaltação plural (v.2), que poderia ser a comunidade manifestando sua exaltação a YHWH, tem uma alternância para o singular no v.4, como o louvor de um indivíduo, e retoma na segunda seção a exaltação plural no v.10. Como parte do livro dos Salmos, que pode ser entendido como uma retribuição humana a Deus, o caráter doxológico é sempre muito presente, principalmente nos Salmos onde se referem a criação, visto que é sempre entendida como uma manifestação da grandiosidade do Deus de Israel, que tudo criou. O Sl 8 apresenta então a criação de YHWH para o homem, e o homem devendo remeter-se sempre a YHWH. / [en] Sl 8, object of study of the present research, is a poetry that describes an aspect of the creation, like a descriptive praise, framed by a corallic refrain. Sl 8 addresses YHWH always in the second person, with inexhaustible exaltations. It presents a central figure of man in the poem, without principle overshadowing the centrality of YHWH in regards to himself. 6-10), such as those with very specific nuances, and patented by their metrics. The first section begins with the exaltation of the plural (v. 2), which could be a manifestation of the exaltation community of a YHWH, it has an alternation to the singular in v. 4, as the degree of exaltation of an individual, and reiterates a plural exaltation in v.10. As the book of Psalms, which can be understood as a human retribution to God, it is a theme that is always present, especially in the Psalms where creation is concerned, since it is always understood as a manifestation of the greatness of the God of Israel, which created everything. Psalm 8 presents a creation of YHWH for man, and man should always refer to YHWH.

Supporting fish populations by restocking with artificially bred young fish is a common practice worldwide, which may sometimes have a negative effect on natural genetic diversity. In this study, the currently ongoing restocking program of brown trout (Salmo trutta Linnaeus, 1758) in the subarctic Pasvik river in Norway was investigated. Previous investigations of this population showed a loss of genetic diversity and both genetic and morphological differentiation between historical breeding stocks and wild trout populations. However, the genetic impact of the breeding program used in this river today has never been investigated. To accomplish this, I compared the parent fish, the offspring, and fish caught in the river using 16 short tandem repeat loci and estimated pairwise relatedness, inbreeding, genetic distances, and differentiation. The results showed, by estimating the effective population size, that the number of parents used in the breeding program was generally insufficient to maintain a genetically sustainable river population. Further, genetic diversity in stocked fish was typically not maximized due to lack of performing all possible crossings between males and females. In combination, this induced genetic drift in the offspring generations and thus genetic differentiation away from the river populations. In summary, the results from this study show that the current stocking practises used in the Pasvik river are not sustainable and that measures need to be taken to prevent continued loss of genetic diversity in this large-growing trout population.