Between May 1 and October 28, 1962, growth data were obtained from 255 specimens of white sturgeon (Acipenser transmontanus, Richardson) from the Fraser River, British Columbia, Canada. Most of the specimens measuring 36" and over in length were those caught incidentally in the salmon fishermen's nets in the lower part, of the Fraser River as far upstream as Langley, British Columbia. Specimens smaller than this length were gill-netted at Dewdney Slough near Mission City, British Columbia. Age was determined for 230 specimens from sections of the first pectoral fin rays. Sections from the rest of the materials were unreadable. Growth in length was studied by averaging observed length at capture and relating these to age, and also by back-calculating growth at the different ages of the fish's life. Growth in weight was studied by averaging the observed weights at times of capture and relating these to age and also by calculating weights at different lengths using the length-weight relationship. From the study of growth in length it was revealed that growth in both sexes is similar up to age twenty, but after that age the females grow faster than the males. It was also revealed that neither of the sexes grows to a fixed maximum length. Study of growth in weight revealed a similar pattern until the fish reached 30", but after that length the females had an advantage over the males. An attempt was made to determine the age at spawning maturity by relating cessation of growth to the maturation of the gonads. It was found that some males start spawning at age eleven, but females may not spawn until they reach age twenty-five to twenty-seven. Periods between spawnings are variable in the different individuals, but may range from five to ten years. A study of the mortality rates in the Fraser River white sturgeon revealed that the present fishing mortality rate is excessive. As a result the fishery is now utilising fish from the young age groups, which may lead to the depletion of stocks. Due to the incidental nature of the fishery it is not practically possible to introduce measures which would effect a reduction in the fishing mortality. It is suggested there be introduced measures which would protect the spawning stocks. These include introduction of a 54" maximum size-limit beyond which length no sturgeon may be taken, complete prohibition of the set-line fishery, and prohibition of sturgeon fishing on the Fraser in the area between Langley and Yale, British Columbia. / Science, Faculty of / Zoology, Department of / Graduate

Depletion of Nelson River sturgeon through over-exploitation by the commercial fishery forced two closures of this fishery between 1921 and 1946. These failures prompted a program of biological research to determine rates of growth, reproduction and increments to stocks to provide a basis for the scientific management of this economically important species of fish. From 1953 to 1956 and 1959, 791 sturgeon were sampled from the commercial catch in the Sipiwesk Lake area of the Nelson River. Preliminary studies were conducted to determine the best method of age determination and back-calculation of growth. It was concluded that the best cross-sections of pectoral "spines", for purposes of age determination and back-calculation of growth, were located at the proximal end of the spine at the base of the swelling which forms the "knuckle"of the spine. The easiest and best measurement on this cross-section for back-calculation of growth was along the radius of the spine from the centre of ossification to the posterior edge of the spine, along the acute angles formed by the annuli in this area. The relationship between fork length (x) and the average radius of the pectoral spine (y) as determined by the method of least squares was: x = .14y + 2.2. In the calculation of size at any previous age, best results were obtained by back-calculating along a line which converged with the intercept. The best representation of growth in Nelson River sturgeon was obtained by cumulatively totalling the average annual calculated increments of growth for a number of specimens. It is readily apparent that female lake sturgeon of the Nelson River grows faster and lives much longer than the male. The average annual Depletion of Nelson River sturgeon through over-exploitation by the commercial fishery forced two closures of this fishery between 1921 and 1946. These failures prompted a program of biological research to determine rates of growth, reproduction and increments to stocks to provide a basis for the scientific management of this economically important species of fish. From 1953 to 1956 and 1959, 791 sturgeon were sampled from the commercial catch in the Sipiwesk Lake area of the Nelson River. Preliminary studies were conducted to determine the best method of age determination and back-calculation of growth. It was concluded that the best cross-sections of pectoral "spines", for purposes of age determination and back-calculation of growth, were located at the proximal end of the spine at the base of the swelling which forms the "knuckle"of the spine. The easiest and best measurement on this cross-section for back-calculation of growth was along the radius of the spine from the centre of ossification to the posterior edge of the spine, along the acute angles formed by the annuli in this area. The relationship between fork length (x) and the average radius of the pectoral spine (y) as determined by the method of least squares was: x = .14y + 2.2. In the calculation of size at any previous age, best results were obtained by back-calculating along a line which converged with the intercept. The best representation of growth in Nelson River sturgeon was obtained by cumulatively totalling the average annual calculated increments of growth for a number of specimens. It is readily apparent that female lake sturgeon of the Nelson River grows faster and lives much longer than the male. The average annual Recommendations for the management of future fisheries on the Nelson River and other areas are given. These pertain to production limits, fishing seasons and the minimum legal size of fish and fishing gear. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (MS)--Montana State University--Bozeman, 2009. / Typescript. Chairperson, Graduate Committee: Christopher S. Guy. Includes bibliographical references (leaves 64-72).

Thesis (M.S.)--Tennessee Technological University, 2009. / Title from title page screen (viewed on Jan. 29, 2010). Includes bibliographical references.

Thesis (M.S.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on June 9, 2006). Thesis advisor: J. Larry Wilson. Vita. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Stevens Point, 2009. / Submitted in partial fulfillment of the requirements of the degree Master of Science in Natural Resources (Fisheries), College of Natural Resources. Includes bibliographical references.

vi, 50 leaves : ill. ; 29 cm Typescript. (Another copy on microfilm is located in Archives) Thesis (M.S.)--University of Oregon Vita Bibliography: leaves 46-50

Scaphirhynchus sturgeons are species of concern throughout their ranges. To revitalize their populations, a thorough understanding of their habitat use during all life stages is critical. However, limited information exists about fine-scale habitat use during early life. To determine the feasibility of using radio telemetry to monitor habitat use in the field, I assessed growth and survival of age-0 sturgeon tagged with 0.2 g, non-functioning telemetry tags during an eight-week period in a controlled setting and then tested field performance in the Middle Mississippi River (MMR). Three treatments were evaluated: 1) control, 2) internally implanted tags, and 3) externally attached tags. Growth and survival varied across treatment groups (all comparisons P<0.05). Sturgeon with internally implanted tags grew slowly and had low survival, while sturgeon within the control group and those with external tags grew faster and had higher survival (~100%). A trial was conducted to determine swimming performance of each of the treatment groups, which resulted in no differences in critical swimming speed among the tag types. Based on these results, a field-based telemetry evaluation was performed to determine if it is feasible to monitor fine-scale habitat use. Four wild, age-0 Scaphirhynchus sturgeon were externally tagged with functioning radio transmitters in the MMR. After less than 24-h, the tagged fish were no longer detectable, likely due to environmental conditions (e.g., extreme depths and high conductivity). Thus, efforts should be directed to creating a small telemetry transmitter that uses technology (e.g., ultrasonic) that transmits well in deep rivers while maintaining a minimum tag weight and maximizing battery life. Fine scale habitat use of age-0 sturgeon may ultimately be able to be quantified in the MMR and other deep rivers in the future, if technologies improve.

In this study, for the first time we used CRISPR/Cas9 gene editing technology in sturgeons i.e., sterlets (Acipenser ruthenus). The sequences of sgRNA and primers were designed based on published dnd1 sterlet sequence. Each pair of sgRNA oligos after ligation ready duplex DNA fragment was cloned into vector pX330-U6-Chimeric_BB-CBh-hSpCas9 backbone and thereafter the transformation to competent cells Escherichia coli DH5 was done. The plasmid carried sgRNA was extracted for downstream applications. We diluted extracted plasmid with 10% of 2 M KCl and injection into animal pole of fertilized eggs of sterlets at one to four-cell-stage, 4 hours post fertilization (hpf). At the same time, second microinjection with 2.5% FITC-biotin-dextrans was injected into vegetal pole for labelling PGCs. In the control groups, the eggs were only injected by 2.5% FITC into vegetal pole. PGCs of sterlet were visualized and photographed using a uorescent stereo microscope Leica M165 FC. To confirm the presence or deletion/insertion occurring in the target gene, we used MCE-202 MultiNA microchip electrophoresis system for DNA analysis, in which the targeted gene after amplifying by PCR was analyzed. Mutations in both treated and control embryos of sterlet were further assessed by Sanger sequencing of the PCR product. In present study, we successfully established basic protocols such as preparation of competent cells, construction of vector carrying sgRNA and its transformation into competent cells to carry out the CRISPR/Cas9 technology in sturgeons. Less number of PGCs was observed in embryos that were treated with CRISPR/Cas9; however, sequencing did not provide us a reliable evidence for mutation of the targeted gene probably due to an unspecific PCR. Therefore, more authentication of dnd1 knockout should be done in future by more specific PCR and repeated sequencing.

Highly profitable black caviar market and the depletion of wild sturgeon stocks warrant improvements in sturgeon aquaculture. Therefore, chromosomal manipulations, particularly gynogenesis, are focused on for increasing the ratio of females over males in progeny. The present study focused on optimizing chromosomal manipulations in sturgeons, particularly gynogenesis. The reasons of low survival rates were analyzed and the critical steps of gynogenesis induction processes were optimized. In addition, alternative ways of DNA inactivation in sperms were investigated, as well as the influence of native light-dependent DNA repair mechanisms on gynogenesis induction. Methods of interspecific gynogenesis usage for simplifying gynogenetic progeny separation were also proposed. Spectrophotometry analysis was used to investigate the ability of UV light, as the most common DNA inactivating agent, to penetrate into sperm. In addition, investigation of UV-irradiated sperm motility and results of partial gynogenesis induction showed that low transparency of sperms for UV-light can cause significant heterogeneity of UV-irradiation. As a result, a proper dilution of sperm was suggested as a critical step for homogeneous UV-irradiation of samples. Gynogenesis in sterlet was induced with chemical agents that damage sperm DNA, as an alternative to UV irradiation for applied in large-scale production of gynogenotes. All tested substances showed ability to inactivate DNA in spermatozoa, and thus producing gynogenotes. Negative impact of treatments with chemical agents on the sperm motility was observed. Subsequently, these treatments had a low efficiency of gynogenesis induction. The highest percentage of produced gynogenetic larvae 19.8 ? 8.9% was obtained by treatment with aminomethyl-4,5?,8-trimethylpsoralen (AMT) at 50 ?M followed by UV-A (360 nm) irradiation at dose of 900 J/m2. Therefore, this treatment could be used as a substitute for commonly used UV-C irradiation, e.g., in the case of large volumes of sperm. Detailed investigation of photoreactivation in sturgeon sperm revealed a significant level of light-dependent DNA restoration in sperms irradiated with high doses of UV-C light. Induction of gynogenesis with UV-C irradiation followed by exposure to visible light resulted in significant deviations from the typical Hertwig effect. In contrast, the red light with a wavelength of more than 600 nm did not result in decreased DNA damage, instead a moderate increase in damage was observed, i.e., it did not induce photoreactivation. Therefore, the use of infrared light to illuminate work stations during the induction of gynogenesis is suggested. The use of interspecific gynogenesis, particularly gametes of sturgeon species with different ploidy levels, was suggested as a way to simplify the separation of gynogenotes. In addition, application of this method allowed studying the effectiveness of DNA-inactivation and ploidy restoration treatments separately, as well as evaluation of fitness parameters and survival rates in each group of progeny without the physical separation of fish. Finally, the protocol for tetraploidization in sterlet was optimized for the prospective using tetraploid individuals for the induction of gynogenesis and androgenesis with diploid eggs and sperm. In conclusion, the described methods and protocols allowed gynogenesis induction in sturgeons with a survival rate sufficient for aquaculture, taking into consideration their high fertility, although further studies of the consequences of this treatment on fish is required.