Jeonghwan Park

Hybrid catfish (♂Ictalurus punctatus X ♀Ictalurus furcatus) production: Does mixed-size production make economic sense?

ABSTRACT Alternative management strategies will be required to produce hybrid catfish (♂Ictalurus punctatus X ♀Ictalurus furcatus) year-round to provide continuous market supply. Hybrid catfish fingerlings were stocked at 9,880 head/ha singly or in co-culture with sub-marketable (mean weight = 454 ± 16 g) hybrid catfish carried over the winter from a previous year’s multi-size trial. Economic analyses compared cost of production (

Seawater Adaptability of Land-locked Masu Salmon Oncorhynchus masou masou by Acclimation

/kg of market-size fish produced) and cash flow of single- and multiple-batch production of hybrid catfish for a single- and two-year period. Gross total and marketable yields were significantly greater in the mixed-size treatment as compared to the single-size treatment, in spite of the significantly greater percentage of market-size fish (84%) in the single-size treatment than in the mixed-size treatment (71%). Cost of production (

Effects of two different ozone doses on seawater recirculating systems for black sea bream Acanthopagrus schlegeli (Bleeker): Removal of solids and bacteria by foam fractionation

/kg) was 4% to 10% lower in the multi-size treatment in the single-year analysis, but 18% to 20% lower when the full two-year cycle was assessed. Cash flow and cash flow risk were improved substantially with the multi-size treatment primarily because the overwintered sub-market-size fish from the previous year reached market size three to four months earlier than in the single-size treatment.

Ozonation in seawater recirculating systems for black seabream Acanthopagrus schlegelii (Bleeker): Effects on solids, bacteria, water clarity, and color

The seawater adaptability of land-locked masu salmon Oncorhynchus masou masou via acclimation was examined for aquaculture purposes. The survival, blood chemistry, and histological changes of masu salmon (150 g) were measured after 7-, 15-, and 30-day acclimation periods. After a total of 60 days in seawater cultures that incorporated the various acclimation periods, survival was 83.5, 87.2, and 91.0% for the 7-, 15-, and 30-day periods, respectively; thus, survival increased with longer periods of acclimation. Feeding efficiencies were 32.1, 52.0, and 40.6% for the 7-, 15-, and 30-day periods, and specific growth rates were 0.14, 0.26, and 0.23%, respectively. Generally, masu salmon appeared to exhibit better growth performance after an acclimation period of 15 days. Cortisol concentrations [mean SD] for 7, 15, and 30 days of acclimation were , , and , with the lowest values occurring with 15 days of acclimation. Osmolarities were , , and mOsm/kg, and glucose concentrations were , , and mg/dl for the 7-, 15-, and 30-day acclimation periods, respectively (P