Study of recirculation semi Intensive Seed Production (RESISP) 1208

Study of Recirculation Semi Intensive Seed Production (RESISP) 1208

Masatoshi FUTAGAWA/CORDUNAP

September 30, 2012

The trial of RSISPC (Recirculation semi intensive seed production with copepod) was conducted from August 26 to September 26 2012. Production of phytoplankton failed due to cloudy weather and the water wasn’t circulated due to low production. The experiment terminated on 42 days culture (DC). Even so, there are some copepods and nauplii were produced.

RESISP1208

Initial water was introduced through 120 µm bag-net, filled up 20 m³, and cultured high density T-Isochrysis (30 L) was added at 0 DC on August 16, 2012. Fertilizer, potassium nitrate (15-0-14, 3ppm) and triple superphosphate (0-14-0, 0.5 ppm) were applied until 9 DC and submersible light (400W) operated 18:00 to 7:00 until 12 DC. Water was supplied 5 % per day and increased 10 to 20 % when pH rise over 8.4 from 14 to 21 DC. Bag-net was removed on 16 DC. Average water temperature and pH at 10 AM showed 17.9±0.3 ºC and pH was 8.1±0.2 through the culture.

Water color turned to green on 3 DC and changed to brown on 5 DC with several single cell and chained phytoplankton. On 11 DC, chain plankton (Skeletonema, Chaetoceros etc.) were abundant. Artificial fish feeds, Love larva #1 (200 µm), applied as 1 g/m³ on 19, 21 and 23 DC. The plankton corrupted, foam appeared on surface and pH down, on 22 DC. Fertilizer applied from 25 to 27 DC and the water was changed 70 % on 28 DC. However, phytoplankton bloom not occurred and water color maintained light color. Finally, drain water totally after sampling on 42 DC. The 1 litter of sample showed 2 copepod (Halpacticoid) and 5 copepod nauplii.

  

Observations

There are several observations that improve phytoplankton and copepod production as below.

• Possibly inoculate useful intensive cultured phytoplankton like T-Isochrysis during initial water, supply 30 % and lighting, and culture useful phytoplankton to produce copepod easily.
• To improve production of copepod is stocking the cultured nauplii to different small tanks after phytoplankton bloom in SISPC tank. Moreover, diapause egg production is ideal to starting copepoda culture anytime.