Access to abstract restricted until 05/2015. / Access to thesis restricted until 05/2015. / Department of Biology

This study combined sedimentation, sediment chemistry and benthic community data from three Oncorhynchus mykiss cage farms in Ontario, along with a laboratory bioassay to examine the effects of aquaculture waste loading. Waste loading rates, as well as sediment TC, TN, TP and metal (Cu, Zn) concentrations were highest beneath the cage and decreased exponentially with distance. During the 21-day bioassay, Tubifex (Oligochaeta, Naididae), Chironomus (Diptera, Chironomidae) and Sphaerium (Bivalvia, Pisidiidae) were subjected to a gradient of waste loading. Survival and growth of Sphaerium simile was highest at intermediate levels of waste loading. Chironomus riparius growth increased with increasing waste addition. Tubifex tubifex growth increased with exposure to fish waste, compared with the control. Until this study, there were no predictions for thresholds of effect at freshwater cage farms in the literature. The proposed threshold of effect on freshwater benthos is 2.0 - 3.0 g C m-2 day-1.

Nototodarus sloanii is an important component of the Southern Ocean fauna, and the basis of a large commercial fishery. Despite this, much is unknown about the biology of this species. This study examines some aspects of the biology of N. sloanii. Stomach contents analysis identified no significant differences in diet between male and female squid. Sixteen putative species, including 12 identifiable teleosts, 2 crustaceans, and 2 cephalopods were identified in the diet of this species. The euphausid, Nyctiphanes australis was the most important prey item, Lanternfish, Lampanyctodes hectoris, and Pearlside, Maurolicus muelleri, were of secondary importance. Squid were aged using counts of statolith micro-increments and back-calculation from the date of capture showed that hatching occurred between August and February, with a peak in the austral winter/spring and another smaller peak in the austral summer. Growth rate for male squid differed depending on whether squid were hatched in the winter/spring or summer. Growth rates were more variable in the winter/spring-hatched individuals, and they attained larger size than summer-hatched squid. This was not the case for female squid. Mean age for immature winter/spring-hatched squid was significantly higher than for summer-hatched squid, although there was no significant difference in mean mantle length or body mass. No significant differences between mean age, mantle length, or body mass for same-gender mature squid, regardless of hatch season, were apparent. However, mature female squid hatched in the winter/spring season were significantly longer (ML) than mature male squid hatched in winter/spring. No squid was found to be older than 211 days. All squid had started to mature by 91-120 days old and all were fully mature at 180 days. Validation experiments run on juvenile squid using calcein markers were inconclusive, however the increments in the statoliths were very similar to those found in other validated species of ommastrephid squid, thus for the purposes of this study they were assumed to be of daily periodicity. Gladius increments identify a gender difference in growth rate, with female squid having a shorter initial slow growth phase than male squid. Gonadosomatic indices (GSIs) were calculated for male and female squid. These were low (7.12%�0.3% for females and 1.9%�0.2% for males) suggesting that these squid are intermittent spawners. This is further supported by a histological examination, which found germinal cells of different stages present in the same gonad. Lack of mature individuals in this study means that these results are suggestive rather than definitive; more examination of the reproductive process of this squid is required. Histological examination was also used to validate the Lipinski maturity scale for use with this species, while some misidentification occurred the scale is useful to place squid into the broad categories of immature, maturing, or mature. New maturity scales were created for N. sloanii utilising these broad categories. Finer-scale identification is not possible using this scale, as maturation appears to be a continuous process. Morphometric measurements were taken from both hard and soft tissues and were analysed using non-metric multidimensional scaling and analysis of similarity. Divisions were only apparent in the hard structure measurements. They did not appear to be age, dietary or reproductive differences.

No description available.

Thesis (Ph. D.)--University of Auckland, 1990. / Includes bibliographical references.

Thesis (Ph.D.)--McMaster University, 2002. / Advisor: Jurek Kolasa. Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.)--McMaster University, 2002. / Advisor: Jurek Kolasa. Includes bibliographical references. Also available via World Wide Web.

Thesis (Ph.D.)--Murdoch University, 2003. / Appendix 1 attached as CD-ROM. Thesis submitted to the Division of Science and Engineering. Bibliography: leaves [156]-173.

Thesis (M.S.)--University of Massachusetts Amherst, 2008. / Includes bibliographical references (p. 97-100).

Thesis (Ph.D. in Cell & Developmental Biology) -- University of Colorado at Denver and Health Sciences Center, 2006. / Typescript. Includes bibliographical references (leaves 151-172). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;