Spatial and Temporal Dynamics of Larval Fish Assemblages in the Strait of Georgia

dc.contributor.authorGuan, Lu
dc.contributor.supervisorDower, John F.
dc.date.accessioned2015-04-30T20:33:30Z
dc.date.available2016-04-03T11:22:07Z
dc.date.copyright2015en_US
dc.date.issued2015-04-30
dc.degree.departmentDepartment of Biologyen_US
dc.degree.levelDoctor of Philosophy Ph.D.en_US
dc.description.abstractFor marine fishes, the early larval phase is considered a critical stage for survivorship and recruitment. The spatial and temporal dynamics of larval fish assemblages can influence their success and trophic structure of marine communities and entire ecosystems. This thesis will provide the first characterization of larval fish assemblage in the Strait of Georgia (SoG) in terms of diversity, abundance and composition, and their variability over multiple temporal scales, as well as the first quantification of variability in larval fish distribution in the SoG across multiple spatial scales. On the interdecadal scale, a significant decrease in larval abundance of several dominant fish taxa (Pacific hake, walleye Pollock, northern smoothtongue and rockfishes) contributed to a decline in total larval abundance and turnover in the composition structure between the early 1980s and the late 2000s. In contrast, both abundance and the relative composition of flatfishes and several demersal forage fish taxa increased during the same period. On interannual scales, abundance, diversity and community structure of the spring larval assemblages varied dramatically through 2007-2010, a period which alternated between strong La Niña and El Niño events. Higher overall larval concentrations were associated with warm conditions in the SoG in 2007 and 2010, while the lowest larval concentration was associated with cooler condition in 2009. Examination of associations between larval fish assemblages and environmental fluctuations suggests a potential influence of large-scale climate processes between the early 1980s and the late 2000s, but a primary association with local environmental factors on interannual scales. Spatial patterns in larval density of three dominant fish taxa (Pacific herring, Pacific hake and northern smoothtongue) were mostly structured on predefined broad (> 40km) and medium (20~40km) scales. Although their scale-dependent associations with environmental factors varied interannually, larval distributions in the central-southern SoG were generally associated with salinity, temperature and vertical stability of water column in the upper layer (0-50m). Our results emphasize the role of local estuarine circulation in structuring hierarchical spatial distributions of planktonic fish larvae in the SoG. These findings will provide considerable implications in fisheries resource management and conservation strategies.en_US
dc.description.proquestcode0416en_US
dc.description.proquestcode0329en_US
dc.description.proquestemailguanlu129@gmail.comen_US
dc.description.scholarlevelGraduateen_US
dc.identifier.bibliographicCitationGuan, L., Snelgrove, P. V. R. and Gamperl, A. L. 2008. Ontogenetic changes in critical swimming speed of Gadus morhua (Atlantic cod) and Myoxocephalus scorpius (Shorthorn sculpin) larvae and the role of temperature. Journal of Marine Biology and Ecology. 360: 31-38.en_US
dc.identifier.bibliographicCitationBradbury, I. R., Gardiner, K., Snelgrove, P. V. R., Campana, S. E., Bentzen, P. and L. Guan. 2006. Larval Transport, Vertical Migration Behavior, and localized Recruitment in Anadromous rainbow smelt (Osmerus mordax). Canadian Journal of Fisheries and Aquatic Science. 63(12): 2282-2836.en_US
dc.identifier.urihttp://hdl.handle.net/1828/6092
dc.languageEnglisheng
dc.language.isoenen_US
dc.rightsAvailable to the World Wide Weben_US
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/2.5/ca/*
dc.subjectlarval fish assemblageen_US
dc.subjecttemporal dynamicsen_US
dc.subjectspatial distributionsen_US
dc.subjectenvironmental driving forcesen_US
dc.subjectStrait of Georgiaen_US
dc.subjectclimate changesen_US
dc.subjectabundanceen_US
dc.subjectdiversityen_US
dc.subjectassemblage compositionen_US
dc.subjectmultiple scalesen_US
dc.titleSpatial and Temporal Dynamics of Larval Fish Assemblages in the Strait of Georgiaen_US
dc.typeThesisen_US

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