Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare.

I describe temporal changes in the genetic composition of a small anadromous Atlantic salmon (Salmo salar) population from South Newfoundland, an area where salmon populations are considered as Threatened (COSEWIC 2010). I examined the genetic variability (13 microsatellite loci) in 869 out-migrating smolt and post-spawning kelt samples, collected from 1985 to 2011 for a total of 22 annual collections and a 30 year span of assigned cohorts. I estimated the annual effective number of breeders (Nb) and the generational effective population size (Ne) through genetic methods and demographically using the anadromous sex ratio. Comparisons between genetic and demographic estimates show that the anadromous spawners inadequately explain the observed Ne estimates, suggesting that mature male parr are significantly increasing Nb and Ne over the study period. Spawning as parr appears to be a viable and important strategy in the near absence of anadromous males.

Approaches for the evaluation of plant protein ingredients for salmonid feeds were investigated in a series of four trials. The first trial compared the apparent digestibility coefficients (ADC) of crude protein (CP) and amino acids (AAs) of two novel products - Indian mustard protein concentrate (IMC, 62% CP) and Indian mustard protein meal (IMM, 42% CP), to a commercially available soy protein concentrate (SPC, 57% CP) for two salmonid species, rainbow trout and Atlantic salmon. The second trial involved assessment of relative bioavailability of arginine (Arg) from IMC, IMM and SPC compared to that of a crystalline Arg (L-Arg) in rainbow trout using slope-ratio assay. In the third trial, the effects of phytic acid (PA) and lignin on nutrient utilization and partitioning in rainbow trout were assessed. Finally, a series of experiments was conducted in the final trial to establish the evaluation criteria for pellet quality assessment. The ADC of CP and most AAs in IMC and IMM were high (>90%). Differences in the ADCs of some AAs can be attributed to the high PA intake by fish fed 30%-IMC diet. The significantly higher (P<0.05) bioavailability of Arg from IMC (123 to 187%) and IMM (116 to 211%) relative to that of L-Arg, as determined by various regression approaches, reaffirmed the findings of the first trial that these ingredients are of excellent protein quality and can readily be used in compounded fish feeds. It can be inferred from the lack of effects of PA, lignin or PA plus lignin on most indices of physiology, performance, and nutrient utilization in the pair-fed fish, that like any other animal, controls feed intake when in the presence of one or more dietary ANF. It was also shown in the pellet quality assessment trial that minor changes in dietary composition can significantly alter physical properties of aquaculture feed. This study highlighted the importance of a comprehensive assessment for the effective evaluation of the nutritive value of plant protein ingredients for use in aquaculture feeds. / Ontario Ministry of Natural Resources; BIOEXX Specialty Proteins Ltd.; Martin Mills Inc.; MITACS

Anthropogenic influences and climate change are warming rivers in New Brunswick and threatening the cold water habitats of native salmonids. When ambient river temperatures in summer exceed the tolerance level of Atlantic salmon and brook trout, individuals behaviourally thermoregulate by seeking out cold water refugia. These critical thermal habitats are often created by tributaries and concentrated groundwater discharge. Thermal infrared imagery was used to map cold water anomalies along a 53 km reach of the Cains River on 23 July 2008. Although efficient and useful for mapping surface temperature of a continuous stream reach, the fish did not use all identified thermal anomalies as refugia. Overall, 100 % of observed large brook trout >35 cm in length were found in 30 % of the TIR-mapped cold water anomalies. Ninety eight percent of observed small brook trout 8 – 30 cm in length were found in 80 % of the mapped cold water anomalies and their densities within anomalies were significantly higher than densities outside of anomalies. Fifty nine percent of observed salmon parr were found in 65 % of the mapped anomalies; however, they were dispersed within study sites and their densities were not significantly different within anomalies compared to outside of the anomalies. No brook trout were observed at the seven noncold water study sites that were investigated. Preference curves for various habitat variables including velocity, temperature, depth, substrate, and deep water availability near cold water anomalies were developed based on field investigations during high temperature events (ambient river temperature >21 oC). Combined with thermal imagery, managers can use the physical descriptions of thermal refugia developed here as a tool to help conserve and restore critical thermal refugia for Atlantic salmon and brook trout on the Cains River, and potentially similar river systems.

Baigiamajame magistro darbe nagrinėjamas sunkiųjų metalų (toliau – SM) keliamas pavojus biotinei ir abiotinei aplinkai, vertinamas eksperimento aktualumas, užsienio šalių bei Lietuvos patirtis šioje srityje. Darbo tikslas – nustatyti SM (Cu, Zn, Ni, Cr, Pb, Cd, Pb) mišinio kaupimosi dėsningumus atlantinių lašišų Salmo salar L. audiniuose (inkstuose, žiaunose, raumenyse, kepenyse) eksperimentinėmis sąlygomis. Gauti rezultatai palyginami su ankstesniųjų metų tyrimų duomenimis, kur analogiškomis bandymo sąlygomis buvo tirtos penkios žuvų rūšys. Nustatyta, kad skirtingos žuvų rūšys skirtingai kaupia SM audiniuose. Lašišoje SM kaupėsi tokia mažėjančia seka: raumenys > žiaunos > inkstai > kepenys. Nustatyti Ni DLK viršijimai raumenyse ir žiaunose, o Pb leistinas kiekis viršytas net 3 audiniuose: raumenyse, žiaunose ir kepenyse. Parengto matematinio modeliavimo rezultatai parodė, kad SM kaupimasis lašišų audiniuose yra specifinis metalui ir audiniui, t. y., skirtingi audiniai parodė skirtingą gebėjimą kaupti SM. Darbo pabaigoje pateikiamos išvados ir rekomendacijos. Darbą sudaro 6 dalys: įvadas, literatūros apžvalga, metodikos aprašymas ir rezultatų analizė, matematinis modeliavimas, išvados ir rekomendacijos, literatūros sąrašas. Darbo apimtis – 90 p., 48 iliustr., 16 lent., 73 bibliografiniai šaltiniai. / The final master thesis discusses potential risks of heavy metals (hereinafter referred to as HM) to theLeopoldas biotic and abiotic environment, relevance of the experimental investigation, Raimondas Idzelis experience of Lithuania and foreign countries in this field. Aim of the work is to evaluate the accumulation patterns of heavy metal mixture (Cu, Zn, Ni, Cr, Pb, Cd) in the tissues of Atlantic salmon Salmo salar L. (kidneys, gills, muscles, liver) in experimental conditions. Results of the work are compared with previous studies, where five species were investigated in the same conditions. It was found that different species accumulate different amounts of HM in the tissues. Salmon accumulate HM in the following descending order: muscles > gills > kidneys > liver. Maximum permissible amount of Ni was exceeded in muscles and gills, while amount of Pb was exceeded even in the three tissues: muscles, gills and liver. Results of the mathematical model showed that the HM accumulation in salmon is specific for metal and for tissue, i.e. different tissues showed a different ability to accumulate HM. At the end of the work general conclusions and recommendations are presented. Structure: introduction, review of literary sources, description of methodology and analysis of results, mathematical modelling, conclusions and recommendations, references. Thesis consists of: 90 p., 48 pictures, 16 tables, 73 bibliographical entries.

No description available.

Leptin is a peripheral adiposity signal and a key hormone in energy balance regulation in mammals, acting as a link between nutritional status and the endocrine reproductive axis. If this is also the role of leptin in fish is not fully understood. This thesis investigates how different components of the leptin system are affected by sexual maturation and seasonal changes in energy balance in male Atlantic salmon (Salmo salar L.) parr under fully fed and feed-restricted conditions. Moreover, the role of sex steroids as being one of the possible mechanisms by which sexual maturation interacts with leptin is explored. The salmon leptin-a genes, lepa1 and lepa2, were expressed mainly in liver and the leptin receptor (lepr) in brain and ubiquitously in peripheral tissues. Seasonal characterization of the lepa genes and lepr during the growth and reproductive season in one-year old males showed that hepatic lepa1 and lepa2 mRNA levels and plasma leptin levels were down-regulated concomitantly with an increase in weight and body fat. Feed restriction up-regulated hepatic leptin, and pituitary lepr expression as well as plasma leptin levels. Correlation between leptin levels and body lipid stores were either lacking or negative. These findings show that leptin and lepr are sensitive to changes in energy balance, but that leptin might not reflect adiposity in juvenile salmon. Hepatic lepa1 and lepa2, and testicular lepr expression increased during mid- to late spermatogenesis in early maturing males. This up-regulation was preceded by rapid gonadal growth and elevated pituitary follicle-stimulating hormone gene expression levels, whereas peak leptin levels coincided with peak pituitary luteinizing hormone expression and the presence of running milt in the testes. The sex steroids testosterone (T), 11-ketotestosterone and 17-β estradiol stimulated lepa1 and lepa2 gene expression in Atlantic salmon hepatocytes in vitro differentially depending on developmental stage. T was also able to stimulate hepatic lepa1 and pituitary lepa1 and lepr gene expression in immature male salmon in vivo. These results suggest that leptin plays a role in male fish reproduction during later stages of the maturational process and that the elevation of leptin expression during spermatogenesis could be caused by androgen stimulation.

Despite the controversy over environmental sustainability, salmon aquaculture in British Columbia is economically important for many coastal communities and is reported as being the largest agricultural export product for the province. This thesis examined the welfare status of commercially produced Atlantic salmon smolts during transport from freshwater farms to the saltwater net pens using physiology and behaviour to assess transport stress. Smolts were transported first by truck from the freshwater farm to the dock, and then in the flow-through cargo holds of a live-haul vessel to the saltwater net pens. Fish and water were sampled before and after truck transport, and several times aboard the vessel. Assessment of stress was based on measurement of plasma cortisol, glucose, lactate, potassium, sodium and chloride concentrations, as well as behavioural observations made on underwater video footage. Seven transports of fish originating from two different hatcheries were sampled; one was a land-based tank hatchery that required a 30-min drive to the dock, and the other a lake net pen facility that was 90 min to the dock. Analysis of plasma constituents supported previous studies that recovery from the stress accumulated during loading and truck transport can be quite rapid in a live-haul vessel. Underwater video footage, recorded at the freshwater farms and in the cargo holds of the Sterling Carrier, also suggested recovery onboard in that for the most part, behaviour onboard was similar to behaviour at the freshwater farms. There were some significant differences between fish from the two types of hatcheries, particularly in the original hatchery conditions and in their behavioural responses to transport conditions; however, post-transport growth and mortality rates reported by the saltwater farms showed no significant difference. Although fish were subjected to moderately stressful conditions during part of the process, smolt transport as currently carried out by our industry partners reflects good husbandry practices and fish welfare.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv. / Härtill 4 uppsatser. I publ. anges Department of Aquaculture som utgivande institution. Med sammanfattning på svenska och franska.

Mémoire (M.Sc. pures) --Université du Québec à Chicoutimi, 1986. / Document électronique également accessible en format PDF. CaQCU