Date of Award

Winter 2008

Project Type

Dissertation

Program or Major

Plant Biology

Degree Name

Doctor of Philosophy

First Advisor

Christopher D Neefus

Abstract

It is crucial for the development of the fish aquaculture industry to be managed in a way that provides a reliable, long term source of products without negatively impacting the environment. The simplest form of integrated multi-tropic aquaculture (IMTA) uses a fed component (e.g. finfish) and an extractive component (e.g. seaweed) to remove the inorganic metabolites from finfish aquaculture effluent. In IMTA systems metabolic wastes become nutrients for the other cultured organisms and are incorporated into potentially valuable biomass. A demonstration-scale Modular Integrated Recirculating Aquaculture Systems (MIRAS) was constructed in a greenhouse adjacent to Great Bay Aquaculture, LLC (GBA), Newington, NH. The MIRAS consists of two independent demonstration scale modular systems each with four 4m3, 3600 L, white fiberglass tanks.

Ammonium production rates were determined for Atlantic cod ( Gadus morhua L.) and nutrient uptake rates for Porphyra umbilicalis Kutzing and P. linearis Greville. The ammonium kinetic characteristics of the fish and seaweed were used to develop a model to predict the system ammonium dynamics. Integrated fish/seaweed trials were run in the MIRAS to test the predictive model using varied fish feed rates and seaweed biomass. The trials showed that the model may be used to predict the effect of various parameters on the system's nutrient levels. Thus, an aquaculture operation may use the model to maintain desired system nutrient levels that will meet the needs of both the finfish and Porphyra and meet production goals. Porphyra produced in the MIRAS was used to partially replace fish meal as a source of protein and omega-3 fatty acids in the cod fish diets. The net effect is to convert a greater portion of the system protein input into fish biomass and to discharge less nitrogenous waste.

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