Program and Abstracts(PDF)

Presentation 21
LANDBASED POLY-ECO-AQUACULTURE OF ABALONE AND SEAWEED IN THE
SMALL SCALE RECIRCULATING SYSTEM USING THE RECYCLED FROZEN
CONTAINER
Mohammad Mustafizur Rahman, Kadowaki Shusaku*, Saw Mya Linn and Yamada Yohei
Faculty of Fisheries, Kagoshima University, Shimoarata 4-50-20, Kagoshima 890–0056, Japan
*Email: kadowaki at fish.kagoshima-u.ac.jp
To minimize environmental impacts, we wanted to develop a poly-eco-aquaculture of abalone
and seaweed in the small scale recirculating aquaculture system housed in the recycled frozen
container. The main objective was to develop a low cost, environment friendly and land-based
integrated aquaculture with hybrid abalone (Haliotis discus hannai × H. sieboldii) and seaweed
(Ulva sp.).
We conducted two experiments in two small-scale recirculating systems housed in a
recycled frozen container (4.3×1.9×1.9 m). Each system consisted of two biofilters (100 and 200
L) and two abalone culture tanks (each 200 L). Each abalone culture tank contained three plastic
baskets (each 50 × 34 × 6 cm, with 12 mm mesh). One of these systems also incorporated a
protein skimmer (PS: 100 L).
An air-conditioner (2.8 kw/h) was used to maintain the desired water temperature (19.2 ±
0.8℃). Water circulation was maintained at 43 L per minute. Artificial salt water was used
instead of natural seawater. Salinity of water was 32 ppt. The stocking density of abalone was 20
individuals per basket. Pelleted artificial feed was supplied six days per week at 2.3% of abalone
body weight per day. Temperature, salinity, dissolved oxygen, total ammonia nitrogen, NO 2 –N,
NO 3 –N, PO 4 -P and bacterial abundance were regularly monitored.
In the first experiment, 3.5 ± 0.8 cm (shell length) abalone were cultured to investigate the
effects of protein skimming on water quality, abundance of bacteria and FCR and growth of
abalone. Over an experimental period of 87 days, protein skimming resulted in significantly
better water quality (lower total ammonia nitrogen, NO 2 –N, NO 3 –N and bacterial abundance) and
abalone growth.
In the second experiment, a seaweed culture tank (100 L) of round and transparent with
conical bottom was connected with the system with PS to observe the combined effects of protein
skimming and seaweed (PSS) on water quality and abalone growth. In this experiment, 4.0 ± 0.2
cm (shell length) abalone were cultured for 72 days. Seaweed (Ulva sp.) was stocked (20 g) in the
seaweed culture tank at the beginning of the experiment and harvested 63~95 g per week. We
observed significantly higher pH and lower TIN and TIP concentrations in system with PSS than
the system without PSS. Bacterial abundance was significantly lower in system with PSS
(4.1×10 5 CFU/mL) than the system without PSS (6.4×10 5 CFU/mL). Bacterial abundance in
protein skimmer waste was 2.2×10 7 CFU/mL. Growth rate of abalone in both length (60.0 ± 8.0
µm/day) and weight (63.6 ± 15.5 mg/day) was better in system with PSS than the system without
PSS (length 40.0 ± 11.0 µm/day and weight 33.8±7.3 mg/day). FCR was observed better in
system with PSS (1.45 ± 0.45) than the system without PSS (2.40 ± 0.26). The survival of
abalone was similar between the system with PSS (96.3 ± 2.5 %) and without PSS (97.5 ± 2.5 %).
ANNOTATED BIBLIOGRAPHY OF KEY WORKS
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