Annex 4 SEAFDEC DEPARTMENTAL PROGRAMS OF ACTIVITIES
2. PROGRAM 1. Objectives
Program Category: Departmental Program Program Title: Mollusk
Responsible Department: Aquaculture Department Duration of Program: Five years (2006-2010) 1. INTRODUCTION
In recent years, there was a fast decline in abalone production from the natural fishery of major abalone producing countries including the Philippines due to heavy exploitation of this resource.
The decreasing commercial catch and the high price of abalone both in the domestic and export markets have stimulated interests in the development of its aquaculture for commercial production and for restocking purposes to enhance its fishery resource.
To help address the needs of the aquaculture industry on abalone, the Mollusk Program of SEAFDEC/AQD focuses its work on tropical abalone, Haliotis asinina. AQD has been in the forefront of developing the technology for controlled hatchery seed production and culture of H.
asinina. Significant results have been achieved in terms of consistent spawning of captive broodstock year-round, improved larval settlement and survival due to improved techniques in large-scale production of diatoms as food for larvae resulting in increased early juvenile production.
In addition to abalone, studies on the biology and fishery as well as developing the hatchery seed production techniques of indigenous mollusk species such as the angelwing Pholas orientalis and sea cucumber Holothuria sp. are being conducted.
technical and economic viability of abalone marketable-size production. This program has a linkage with the Stock Enhancement/Sea Ranching Program in that it provides hatchery- produced juveniles or seeds for stocking.
3. PROGRESS OF ACTIVITIES IN THE YEAR 2007
Improvement of hatchery techniques for the donkey’s ear abalone Haliotis asinina
Experiments were conducted on broodstock maturation, larvae management and transport protocols for larvae and juveniles. Results on broodstock maturation in indoor and outdoor holding tanks were similar in terms of gonadal maturation and rematuration frequency, and spontaneous spawning. In larvae management, stocking of larvae immediately after collection or 6 hours later showed better survival at day-10 than those larvae held for 12 or 24 h after retrieval. Delaying the stocking or holding the larvae for 12-24 h after retrieval induced higher mortalities ranging from 20-40%, respectively.
For simulated larval transport experiments, trochophore larvae loaded at 50,000/liter and transported within 6 h in oxygenated plastic bags at 20-22oC had better survival than those loaded at 25 or 100 larvae/liter or when transported at higher temperature (24-25oC). For juveniles, higher survival (80-95%) was obtained in bigger juveniles (20-23 and 25-29 mm shell length) and transported at temperature of 24-25 after simulated transport within 30 h than in small juveniles (10-19 mm shell length) or transported at 18-21oC.
The effects of light intensity and photoperiodicity on the settlement rate, feeding behavior, growth and survival of abalone (Haliotis asinina) post-larvae
Under standard hatchery rearing conditions, microscopic examinations were done on day1 to day 15 larvae to examine the presence of food in the gut. No ingestion was observed on day 1 to day 4 larvae. The presence of food in the gut was observed starting day 5 until day 15.
The number of swimming larvae was monitored on day 1 to day 4. On day 1 – day 2, swimming larvae were found in the water column. On day 3, some larvae were swimming in the water column and some larvae had settled in the plate. Starting day 4 no larvae can be observed in the water column.
Two fifteen days experiments were conducted in one-liter plastic container. During the first run, mass mortality occurred a day after stocking, while a very low settlement (insignificant) was recorded on the second run. To evaluate the cause of poor settlement in the above runs, a five-day experiment was conducted indoor in the same rearing container. The four parameters tested are as follows; A-no aeration, B-with aeration, C-no aeration + flow through on the 3rd day and D-with aeration + flow through on the 3rd day. Results showed higher percentage of swimming larvae (8.6%) in treatment A after 3-5 days of rearing. The percent settlement of larvae after 3-5 days of rearing was similar (3.4-3.5%) in treatments A and D. The percentage settlement of larvae at different location (light intensity) and reared in 1 liter plastic container is not distinct. At different locations, ingestion of diatoms starts at day 3.
Lipid and essential fatty acid requirements of juvenile abalone, H. asinina
Preliminary results showed the proximate composition of the abalone meat in percent dry basis:
67% protein, 3% crude fat, 16% nitrogen-free extract, and 11.4 crude ash. Feed formulation is in process.
Verification of some hatchery techniques for the donkey’s ear abalone H. asinina
During the third quarter (July-August only), more than 25 million veligers were produced from 48.87 million trochophore eggs collected or about 61.3% survival. A total of 147 females were spawned during the two-month monitoring of spontaneous spawning. Total early juvenile production during July-August was 46,418 individuals. Production of pure cultures of diatoms amounted to 287 liters from where the 51 tons of Navicula and Amphora were produced in outdoor culture tanks at Phycology Wet Lab. At the abalone nursery outdoor tanks 62 tons of diatoms were produced that were used for seeding in abalone.
A modular system of culturing abalone, H. asinina in mesh sea cages
Abalone juveniles with initial body weight of 0.84 g and shell length of 16.4 mm were stocked at 600 per unit of circular mesh cage. After three months, the stocks were reduced to 300 stocking density/cage and were distributed to similar cages. After 5 months of culture, abalone attained an average body weight and shell length of 17.2 g and 42.3 mm, respectively. Average daily growth rates in weight and shell length were 109 mg day -1 and 172.67 um day -1, respectively . FCR is estimated at 14 with mean survival rate of 80 %.
The second batch of juveniles attained after a 60-day culture period a mean daily growth rate of 73.5 mg day -1 and 208.33 µm day-1. FCR is estimated at 8 with mean survival rate of 96 %.
Both batches exhibit high growth rates, good FCR and SR.
Extension. A Pilot-testing of abalone hatchery technology in collaboration with a private sector was conducted from August 2006 to August 2007. The cooperator was selected on his capacity to provide basic facilities for the rearing of abalone postlarvae until the advanced juvenile stage and has undergone intensive internship training at the SEAFDEC abalone hatchery. From September 2006 until June 2007, the cooperator availed a total of 10 million veliger larvae that produced around 116,557 early and advanced juveniles or an average survival of 1.64% (range:
0 - 6.4%).
Training. A 21-day International Training course on Abalone Hatchery and Seed Production was conducted on 6-26 September 2007. A total of 18 participants from Malaysia, Myanmar, Indonesia and Philippines from both the government and the private sector, attended the course.
Two of the foreign trainees SEAFDEC-member countries and two from Philippines were funded by the Government of Japan-Trust Fund while the rest were paying participants.
On-the-Job and Internship training are conducted at the Abalone Hatchery and Nursery Facility in coordination with the Training & Information Division. Students from nearby colleges and universities as well as private individuals had their summer job training and internships at the Hatchery.
4. PROPOSED FUTURE ACTIVITIES FOR THE YEAR 2008