Date of Award

Fall 12-16-2014

Document Type

Thesis

Degree Name

MS Marine Science

Department

Environmental and Ocean Sciences

Committee Chair

Dr. Ron Kaufmann

Committee Member

Dr. Dan Schlenk

Committee Member

Dr. Bethany O'Shea

Abstract

Contaminated sediments in marine environments have been shown to be good indicators of ecological risk and a means to assess anthropogenic impacts on marine habitats and the animals that inhabit them (Long et al. 1995, Rattner 2009). Estuarine sediments are especially complex media with regard to physical, chemical, and biological characteristics that trap, store, modify and sometimes release contaminants to the biota (Long et al. 1995). Especially vulnerable are animals that are in constant contact with the sediments, such as flatfishes that partially bury themselves for camouflage (Costa et al. 2011). Impacts can be assessed in a number of ways, one of which involves measuring biomarkers, changes in biological responses ranging from molecular through cellular and physiological responses to behavioral modifications that can be related to the magnitude and duration of exposure (van der Oost et al. 2003). Examining the effects of contaminants on fishes in complex environments requires using multiple biomarkers, which is why a preferred method in areas with sublethal concentrations of contaminants is to use a combined biomarker index to quantify impacts (Sole et al. 2010, Pereira et al. 2010a, b). Juvenile California halibut (Paralichthys californicus) use bays and estuaries as nursery habitats during their first year of life (Forrester and Swearer 2002, Fodrie and Mendoza 2006, Fodrie and Herzka 2013). Studies of young halibut show that they prefer shallow areas with fine sediments and gradually move into deeper, sandier habitats as they grow (Fodrie and Herzka 2008, Lopez-Rasgado and Herzka 2009). In Mission Bay, San Diego, higher concentrations of multiple inorganic and organic contaminants have been found in the back bay (which is shallow with fine sediment and receives input from storm water outfalls) and in boat basins, although not at levels that are acutely fatal to juvenile halibut (Stransky 1999). Some contaminants of interest in Mission Bay are heavy metals (Cu, Pb, Zn) and compounds associated with anthropogenic inputs, like petroleum hydrocarbons, pesticides and other organic contaminants that have the potential to bioaccumulate. The purpose of this project was to compare contaminant concentrations in sediments to liver, kidney and gill biomarkers in juvenile California halibut caught in different parts of Mission Bay to examine relationships between the distribution of contaminants in Mission Bay and physiological condition of juvenile halibut.

Available for download on Thursday, June 29, 2017

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