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Memorial University - Electronic Theses and Dissertations 5
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TitleEffect of spatial and environmental factors on the reproductive cycle of the brittle star, Ophiopholis aculeata, based on a new maturity stage index
AuthorDoyle, Gina Marie, 1986-
DescriptionThesis (M.Sc.)--Memorial University of Newfoundland, 2011. Biology
Paginationxvi, [148] leaves in various foliations : ill.
SubjectOphiuroidea--Reproduction--Effect of temperature on; Ophiuroidea--Reproduction--Climatic factors; Ophiuroidea--Reproduction--Environmental aspects; Gametogenesis--Research
Degree GrantorMemorial University of Newfoundland. Dept. of Biology
NotesIncludes bibliographical references.
AbstractMonthly collections of the brittle star Ophiopholis aculeata were made and individuals were analyzed using traditional methods (gonad indices, gametogenic stages and oocyte diameters), along with a newly developed quantitative method coined the 'maturity stage index' (MSI). The MSI was statistically related to conventional methods of studying reproduction, but provided greater sensitivity for fine-scale and inter-individual comparisons. This allowed the study of reproductive synchrony in O. aculeata over several scales: (1) within a given habitat, (2) between adjoining habitats, (3) among individuals in each habitat, and (4) within and among natural clusters of individuals. Complementary laboratory trials were conducted to further examine the influence of temperature and spatial distribution on gametogenesis. Ophiopholis aculeata exhibited an annual gametogenic cycle with spawning in late summer. Significant differences were seen between habitats and among individuals in certain months, and synchrony was generally greater around the time of spawning and in nearby/grouped individuals. Laboratory experiments indicated that temperature is unlikely to act as a proximate reproductive cue, and phytoplankton is probably the major environmental factor mediating the annual reproduction of O. aculeata. Together, field and laboratory findings further evidenced the synergistic roles of exogenous factors and inter-individual communication in coordinating the reproductive cycle of marine invertebrates.
Resource TypeElectronic thesis or dissertation
FormatImage/jpeg; Application/pdf
SourcePaper copy kept in the Centre for Newfoundland Studies, Memorial University Libraries
RightsThe author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
CollectionElectronic Theses and Dissertations
Scanning StatusCompleted
PDF File(19.15 MB) --
CONTENTdm file name22196.cpd