|dc.description.abstract||This dissertation describes catfish production over four-years using In-Pond Raceways Systems (IPRS). This technology consists of a floating raceway (RW) cage placed into an existing pond, which allows for more control of the production cycle by confining cultured fish into a smaller volume of water compared to a traditional pond. Also, it facilitates feeding, chemical treatments, and inventory control. Our overall objective is to support the development and establishment of a more profitable catfish production system, possibly through adoption of the IPRS as an additional, alternative method. Raceway configurations used in this project were “growout units” of 63 m3 (located in ponds 1 and 2) and 45 m3 (located in ponds 3 and 4) with a total of 2.5 HP WWU (White Water Unit) of aeration per pond used in study 1, and 4.0 HP WWU in study 2 (Chapter 2). Growout units refer to the final catfish product being of harvestable size and ready to go to the processing plant. For study 3, a 14 m3 “stocker unit” was placed next to each growout unit and was used to grow fingerlings to stocker size. The idea being that once growout units were harvested, the produced stockers would be harvested and placed into the vacated, adjacent growout unit for growth to foodsize fish and future use (Chapter 3). For study 4 (Chapter 4), a 36 m3 tilapia cage was placed into 2 of the 4 ponds (ponds 2 and 4). For studies 3 and 4, an extra blower was added totaling 5.0 HP for WWUs that maintained adequate DO levels at these high biomass levels. The following chapter briefs present study approaches and results from the four research years with details in the actual chapters.
Chapter 2 evaluated catfish growth performance and economic efficiency for two sizes of floating IPRS units using two stocking density approaches. Two year-long independent IPRS experiments were conducted using Channel Catfish and hybrid Catfish. Results from studies 1 and 2 showed that initial raceway cost had a great impact on the long-term feasibility of the system. Raceways made with less expensive materials had a higher profit potential but were characterized by shorter economic lifespans. Lower initial farm level investment reduced the payback period, increased net present values and internal rates of return. White-water units kept homogeneous temperature and oxygen levels in pond water columns. IPRS catfish feed conversion ratios were more efficient than in traditional pond systems. Hybrid Catfish had better growth performance and economic returns than Channel Catfish.
Chapter 3 evaluated the performance and economic efficiency of producing foodsize hybrid Catfish and stocker sized fingerlings in two separate IPRS units. Results from study 3 showed that yields from these IPRS raceways surpassed those from traditional catfish pond systems. Again, initial raceway cost had a great impact on the long-term feasibility of the IPRS system. Feed conversion ratios ranged between 1.62 to 1.8 for stockers and foodsize hybrid Catfish produced in the IPRS systems.
Chapter 4 evaluated fish production and growth performance for hybrid Catfish raised in IPRS in four ponds, along with tilapia grown in cages without feed in two of the four ponds. Results from study 4 showed that we achieved remarkably consistent catfish and tilapia production results across all ponds. Hybrid Catfish raised in IPRS units had had survival rates, with very high counts at harvest compared to the stocking number, demonstrating excellent fish inventory control with this technology. IPRS promoted uniform hybrid Catfish production, with 90 to 95% of the foodfish harvested in the preferred premium size range. Feed conversion ratios ranged between 1.42 to 1.80 for stockers and foodsize hybrid Catfish. Production strategies for inclusion of co-cultured tilapia along with the catfish IPRS systems were achieved with little investment and low operating costs, resulting in overall positive net returns. Polyculture production of catfish and tilapia could provide an opportunity to reach diverse niche marketing segments. Ponds housing IPRS catfish units plus a tilapia cage had reduced investment payback periods, increased net present values, and higher internal rates of return. In-pond raceways offers yet another technology that could advance intensive fish culture in the U.S. and world.||en_US