This thesis details the spatial and temporal influence of integrated multi-trophic aquaculture-derived organic effluent on the diet of cultured organic extractive organisms within an integrated multi-trophic aquaculture (IMTA) facility in Kyuquot Sound, British Columbia. Naturally occurring and aquaculture-derived sources of nutrients were defined using isotopic analysis of δ15N and δ13C values, in order to examine feeding patterns of a cultured bivalve species C. gigas. By examining the diet of C. gigas located within the IMTA system, and at a reference site, spatial and temporal patterns of organic-effluent influence on organic extractive components within the IMTA system can be defined. Measurements were performed over four seasons (Spring, Summer, Autumn, and Winter) at a reference site and at stations adjacent to the fish component of the IMTA system, at distances of 0m, 15m, and 30m. Oysters at each station were suspended in the water column at depths of 6m and 18m. Chapter two of this thesis focuses on the vertical and horizontal patterns of aquaculture derived particulate waste influence on organic extractive components within the IMTA system. Examination of δ15N and δ13C values sampled from C. gigas tissue at each station indicated both horizontal and vertical dispersion, and subsequent uptake, of aquaculture-derived effluent. The importance of aquaculture-derived effluent to the diet of C. gigas was not uniform across stations or seasons. General trends indicate the strongest reliance upon aquaculture-derived effluent as a nutritional subsidy by C. gigas suspended at depths of 18m, and those located 15m and 30m adjacent to the fish component of the IMTA system in particular. This chapter also focuses on the examination of C. gigas feeding patterns using stable isotope analysis over a seasonal timescale, to describe temporal variability in the importance of aquaculture-derived effluent to the diet of organic extractive components within an IMTA system. Examination of δ15N and δ13C values sampled from C. gigas tissue at each station indicated strong seasonal shifts in importance of aquaculture-derived effluent as a nutritional subsidy to oysters within the IMTA system. General trends suggest that C. gigas cultured within the IMTA system feed most heavily upon aquaculture-derived effluent during the winter and spring months, while importance of naturally occurring food sources are more heavily relied upon during the summer and fall months. . / Graduate