The aquaculture industry in California is highly diversified in terms of the species cultured and the production systems used. This diversity creates special challenges and opportunities for research. Past and current aquacultural engineering work in the department ranges from relatively low intensity pond systems to highly intensive recirculation systems. Species cultured in the systems studied in the department range from warm to cold water fish and from fresh to sea water and include California halibut, catfish, sturgeon, striped bass, tilapia, and trout.
On a worldwide basis and compared to other types of systems, ponds account for the largest proportion of aquaculture production. Departmental research on aquaculture ponds has focused on the development of computer models of water quality and fish production. These models can be used to simulate critical water quality parameters and fish yield as functions of environmental conditions and feeding and fertilization regimes. The models can be used for research, teaching, and planning purposes.
Intensive tank and raceway systems usually include water treatment operations designed to improve effluents such that either environmental regulations are met, or the water can be reused by recycling it through the production system. Research projects carried out in the department have focused on a variety of water treatment operations, including solids removal through sedimentation and filtration, carbon dioxide removal by aeration, and ammonia removal by biofiltration. In addition to these projects in which individual unit operations have been considered, research has been carried out on the development of energy efficient recirculation systems incorporating the full range of water treatment unit operations needed to maintain acceptable water quality. Computer models of recirculation systems and water treatment unit operations have been developed for the simulation of water quality and resource (water, oxygen, feed) use in intensive systems with water reuse.
Effluents from many aquaculture operations in California are used for crop irrigation. This procedure optimizes the use of our water resources and recycles some of the waste nutrients from the fish. The student in this photograph is collecting a sample of effluent for nutrient analysis.
Water samples are analyzed frequently to ensure safe conditions for fish. This particular farm uses a variety of culture systems ranging from conventional ponds to intensive recirculation in tanks