Abalone now being cultured in the Philippines
By MVRicafrente
SEAFDEC_AQD spearheads he study on abalone culture to meet the growing market demand in the country.
Among the tropical abalone species, Haliotis asinine is the largest, reaching a maximum shell lengh (SL) of 100 cm. H. asinine matures at 30-35 mm SL and grows to a marketable size of size of 5.5-60 cm within one year.
Abalone, a herbivore, feeds on micro-algae (epiphytic diatoms) during its early life stage. During the juvenile stage. It feeds on seaweeds. In the SEAFDEC Aquaculture Department (SEAFDEC-AQD) hatchery, broodstock of abalone are fed with seaweeds, particularly Gracilariopsis bailinae, a seaweed species that is easy to grow in brackish water ponds and drainage canals in central Philippines.
In the Philippines, the commercial abalone catch reached 448 mt in 1996 but dropped to 190 mt in 1998.
In 1998, Dr. Armando C. Fermin of the SEAFeDC-AQD based in TIgbanauan, ILOILO conducted a study which aimed to determine the effects of various shelter surface area (SSA) on the feeding , growth and survival of the donkey-ear abalone, Haliotis asinine reared in mesh cages suspended in flow-through tanks. The study also verified the effectiveness of the macro-alga Gracilariopsis balinae for growing the abalone for nine months.
Prior to Dr. Fermin’s study, 100-mm hatchery-bred abalone juveniles from the Deparment’s mollusk hatchery were reared for 90 days in perforated plastic basket suspended in flow-through tanks. Three months after feeding with Gracilariopsis balinae, the abalones grew to shell length of 30 mm.
Abalones with shell lengh of 32 mm and body weight (BW) of 7.5 g were stocked in cages doubled-lined with black nylon mesh measuring 3 x 5 mm. Cages were subdivided into sections provided with polyvinylchloride (PVC) that served as shelters.
In a six-ton indoor tank, 12 cages were suspended and continuously supplied with sand-filtered sea water at a turnover rate of 200% day. The water depth was maintained at 90 cm. Through the perforated PVC pipes laid at the tank bottom, aeration was provided. A pre-determined amount of G. bailiniae was added to each cage at weekly intervals for a 270-day culture period. Left-over seaweed was collected, drained and weighed at the end of each week. Before the seaweeds were weighed, they were drained to remove excess water.
At the end of the culture period, the body size of the abalone ranged from 56-69 mm SL and 52- 57g wet BW with significant difference from abalones cultured at SSA 0.22/m square and 66/m square. The study showed that G. bailinae is an excellent , inexpensive and readily available feed for abalone with a feed conversion ratio of 26-27. Sea cage trials showed that H. asinine with an initial size range of 35-40 mm SL stocked at 43/m square attained at harvest size of about 60 mm SL and 62g BW for 180 days.
For better grow-out rearing in suspended mesh cages, H. asinine juveniles can be stocked at 75 to 125 / m square with SSA or ).44 to 0.66 m square and SSA: CV ration of not less that 10 in flow-through tanks. Further-more, the study has proven that a mono-specific diet of red seaweed Grailariopsis balinae was effective for growing H. asinine in cages for nine months. Observation of the marketable size, high survival and growth rate of H. asinine are currently being made for a period of up to one year/
At harvest time, an average of 4 kg/ m square of abalone with size range of 20-30 g each are gathered, although market size varies, depending on the size preference and season. Farm-gate prices fluctuate and vary with the supply. A kilo of abalone (live weight) sells from 30-40 dollars. The large the abalone , the cheaper the unit price.
The annual rate of return of investment ranges from 50-160% depending on survival, duration of operation, investment cost and sale price.
Source: MARID Agribusiness, February 2007