Research that works for developing countries and Australia
Sustainable tropical spiny lobster aquaculture in Vietnam and Australia
Project ID: FIS/2001/058: Sustainable tropical spiny lobster aquaculture in Vietnam and Australia Commissioned Organisation: CSIRO Marine Research, Australia Project Leader Dr Kevin Williams Phone: 07 3826 7284 Fax: 07 3826 7222 Email: kevin.williams@csiro.au Collaborating Institutions:
- Research Institute for Aquaculture No. 3, Vietnam
- Queensland Department of Primary Industries and Fisheries, Australia
- Institute of Oceanography, Vietnam
- University of Fisheries, Vietnam
- Directorate General Aquaculture, Indonesia
Project Budget: $1,083,200 Project Duration: 01/01/2005 - 30/06/2008Project Extension: 30/06/2008 - 31/12/2008ACIAR Research Program Manager Project Overview Market demand for lobster is rising throughout much of the world, despite lobster fisheries being fished at either maximum capacity or being in decline. Meeting this demand in a sustainable fashion is increasingly dependent on aquaculture production. Current lobster aquaculture in Vietnam relies on the collection of wild seed which in turn has high rates of mortality in caged grow-out facilities. There is also evidence aquaculture is having a detrimental affect on coastal environments. These concerns will be addressed through:
- an assessment of ecological impact seed collection in Vietnam
- reducing post-capture losses
- development of best practice husbandry for grow-out
- capacity building and technology transfer.
Project Progress Reports Year One Delays in obtaining signed Project Agreements between the contractual parties meant that research activities of the project did not commence until July-August 2005. Consequently, project start-up was delayed by 6+ months. This delayed start, in the context of the project as a whole, should not greatly affect the delivery of the planned outputs.
Ecological impact of lobster seed collection in Viet Nam
A pilot census of lobster seed collection at Khanh Hoa Province was carried out by Institute of Oceanography Nha Trang (ION) during October 2005 to trial census procedures. A full census is now being implemented to survey lobster seed collection in the seven central coast provinces of Viet Nam where lobster settlement occurs. A total of 82 lobster seed merchants have been identified who operate in the south central provinces and information on seed collection has been obtained from 38 of these dealers. University of Fisheries (UoF) is implementing a survey of the seasonal incidence of breeding activity of caged lobsters. These surveys by ION and UoF will continue for the life of the project and will provide reliable data for use in estimating the sustainability of lobster culture in Viet Nam.
Reducing post-capture losses of seed lobsters
Lobster seed merchants at three major landing ports of Bai Xep (Binh Dinh), Xuan Dai (Phu Yen) and Nha Phu (Khanh Hoa) have been interviewed to determine the procedures used to hold and distribute captured lobster seed. Based on this information, Research Institute for Aquaculture No. 3 (RIA3) is examining the effects of different holding methods (stocking density, holding duration and feed type) and transport conditions on lobster survival over the critical 30-day post capture period. Because lobster vitality appears to be strongly related to settlement time, experiments will be done with lobster seed collected early, mid and late in the settlement season to examine seasonality effects. Preliminary results with early season pre-juveniles suggest that extending the time between capture and placement in nursery cages from 1 to 2 days markedly reduces the ultimate survival of the lobsters during the 30-day nursery period. Stocking density is not a major factor affecting lobster survival whereas long transport times (6 or more hours) are, with nursery survival rates below 27%. Feeding Kuruma shrimp pellets during the nursery period resulted in survival rates and weight gains only slightly worse than feeding trash fish.
Husbandry best-practices for lobster grow-out
Improved and less-polluting methods for seacage grow-out of lobsters:
An experiment to see if culturing lobsters and mussels together improves lobster cage productivity and adjacent environmental conditions has been planned by ION to commence early 2006. Suitable culture sites at Nha Phu Bay (Khanh Hoa) have been identified and lobster farmers from Xuan Tu village have agreed to collaborate in the work. The experiment will be carried out over 18 months with production, environmental and food safety data being collected at 6-monthly intervals.
Improving lobster grow-out feeds:
In Viet Nam, UoF is investigating ways of optimizing the utilization of trash fish, both to maximize growth and survival of the lobsters and also to reduce the environmental impact of this type of feeding. In addition to determining how best to combine the different types of trash fish that are available, the work will examine different methods of moist pellet production, including transglutaminase enzyme binding, which is thought to offer the best prospects for developing an effective means of binding and yet simple enough to be carried out on-farm. At CSIRO, two experiments have been carried out to determine the apparent nutrient and energy digestibility of a total of eight key dry feed ingredients: Chilean fish meal, Antarctic krill meal, NZ mussel meal, lango crustacean meal, Japanese squid meal, dehulled narrow-leaf lupin, solvent-extracted soybean meal and wheat. Results for the first four feed ingredients are available and show that protein digestibility was high for all ingredients (84-89%) but the digestibility of dry matter, lipid and energy varied inversely with the amount of ash and chitin in the meal. CSIRO research in 2006 will determine the dietary cholesterol requirement of juvenile (2-50 g) and sub-adult (500+ g) lobsters.
Land-based systems for lobster culture:
Major tasks for Queensland Department of Primary Industries & Fisheries (QDPIF) during this period were to appoint staff, establish experimental grow-out systems and develop lobster seed collection processes and tools to effectively secure sufficient numbers of juvenile lobsters to sustain the experimental program for both QDPIF and CSIRO Marine Research & Atmospheric Research (CSIRO). Staff has been appointed and two 16-unit experimental systems have been established at Northern Fisheries Centre. However, the delayed start of the project meant that it was late in the settlement season when collectors could be deployed and only small numbers of seed lobsters were captured. These were used by QDPIF to commence a 3-month experiment investigating the effect of lobster size uniformity on growth and survival of the lobsters. The hypothesis is that a narrow size range within a collective group of lobsters will benefit the overall survival and growth of that group, and that regular size grading will be a useful tool in improving productivity of commercial operations. Four size ranges (20, 40, 60 or 80% variation around the mean) are being examined. The experiment is due to be completed in January 2006.
Year Two Good progress has been made in overcoming the delayed start-up of the Project and the work is on track for completion as scheduled by 30 June 2008 or shortly thereafter.
Ecological impact of lobster seed collection and seasonal incidence of breeding in caged lobsters in Viet Nam
ION staff carried out a census of lobster seed collection along the central coast of Viet Nam over the period of October 2005 to April 2006. This entailed a survey of 71 of the known 81 dealers and 33 of the 34 lobster farming villages in the eight central coastal provinces from Da Nang in the north to Binh Thuan in the south. Total recorded collection of Panulirus ornatus seed was 1,917,910 with the three central Provinces of Binh Dinh (453,450), Khanh Hoa (415,690) and Phu Yen (414,860) recording the highest numbers. It is thought that this census represented at least 90% of total Vietnamese P. ornatus seed collection. A census for the 2006/07 settlement year has commenced with 86 dealers and 31 lobster farming villages providing data. Settlement numbers so far appear to be lower than last year with average catches of only two individuals per boat per night. The price of the seed this year has risen more than 10% and currently is 175-185 thousand Dong (AUD$ 17-18) per individual. NTU staff surveyed the incidence of breeding in caged lobsters in four lobster farming villages in Khanh Hoa and Phu Yen Provinces in May-July and again August-December, 2006 Where males and females were caged together almost all females over 600-700 g were berried while only a few lobsters over 900 g were carrying eggs. Farmers reported that most females with eggs after December would succumb to fungal infection of the egg mass, most likely due to deteriorating water quality at this time.
Reducing post-capture losses of seed lobsters
RIA3 staff carried out two experiments to examine the effects of stocking density, initial holding time, subsequent transport time and feed type on growth and survival of seed lobsters from time of catch through to 90 days of nursery culture. The results indicated that within the bounds of current commercial practices, stocking density and initial land-based holding time had only slight effects on subsequent growth and survival of the lobsters. However, increasing transport time from 1 to 6 or 12 hours had a profound adverse effect on survival rate, which often was apparent only after 30 days of nursery culture. Examination of the effect of feeding either a formulated diet or trash fish during the nursery phase was confounded by low acceptance of the formulated diet by the lobsters. Improved transport methods are currently being compared to find better methods that reduce the stress on the lobsters during transport. In a third experiment that is currently under way, four different 6-h transport conditions (static, normal aeration with or without shelter and compressed air without shelter) has resulted in 100% survival after transport. The effect these transport conditions have on lobster growth and survival during the nursery phase is under investigation.
Husbandry best-practices for lobster grow-out
Improved and less-polluting methods for seacage grow-out of lobsters:
An experiment to see if culturing lobsters and mussels together improves lobster cage productivity and adjacent environmental conditions commenced in March 2006. Four cage sites in Nha Phu Bay (Khanh Hoa) and four cooperating lobster farmers from Xuan Tu village were chosen for the work. At two of the sites, lobsters are being co-cultured with green mussels (Perna virdis) while at two of the sites, half of the cages on experiment are being fed only trash fish while the other half are additionally being fed with mussels. Lobster productivity (survival, growth, food allocation) is being monitored monthly with 6-monthly monitoring of water column, sediment and mussel and lobster tissue for chemical (including heavy metals) and microbiological status. The experiment will continue for 18 months. After 8 months of culture, feeding either trash fish or trash fish plus mussel appears to have had no effect on survival or growth of the lobsters. However, two of the sites are showing higher lobster growth rates but this appears to be unrelated to mussel co-culture. Some site-specific environmental differences are being observed, both within and between sampling times (May and October 2006), but these cannot be attributed to the imposed experimental conditions. Effects of season, river inflow and other land and cage pollutants are thought to be having as great, if not greater, effect on the environmental conditions at the cage sites. Heavy metal analysis of mussels and lobsters have recorded levels below the maximums set for seafood safety and while Vibrio and fecal coliform counts were high and universally present in water column, sediment and mussel tissue (Vibrio only), no pathogenic bacteria were found in any of the lobster samples.
Improving lobster grow-out feeds:
In Viet Nam, NTU is investigating ways of optimizing the utilization of trash fish, both to maximize growth and survival of the lobsters and also to reduce the environmental impact of this type of feeding. In the first of two 8-week growth assay experiments, three different types of trash fish (lizard, bream or anchovy) and two vitamin supplementation levels (with or without vitamin premix) were examined factorially when made into moist feeds using transglutaminase (TG) binding methods (Annex A). Initial statistical analysis of the results showed no significant treatment differences but strong trends for improved growth of vitamin-supplemented lobsters and those fed the lizard fish as the trash fish source. In the second experiment, the effectiveness of three different binders - Magicoh (an urea-formaldehyde binder), TG and an undisclosed USA binder - were evaluated. Water stability of the semi-moist pellets was best for the TG-bound diets while lobster growth rate was significantly better for the Magicoh and TG-bound diets than the USA binder.
At CSIRO, work determining the apparent nutrient and energy digestibility of eight key dry feed ingredients - Chilean fish meal, Antarctic krill meal, NZ mussel meal, lango crustacean meal, Japanese squid meal, dehulled narrow-leaf lupin, solvent-extracted soybean meal and wheat - was completed. Apart from an unexpectedly low digestibility for the squid meal, the digestibility of all other test ingredients was similar to that observed with other decapod crustaceans. The main focus of CSIRO research has been to determine the dietary cholesterol requirement of sub-adult (600-700 g) and juvenile (~0.5-3.5 g) lobsters. In a 6-week depletion and 16-week repletion cholesterol experiment, sub-adult lobsters were fed TG-moist feeds that in the repletion phase provided incremental amounts of cholesterol from 0.15 to 0.45% (DM basis). Based on cholesterol content of the digestive gland, a dietary cholesterol level of 0.35% was sufficient for these lobsters when the diet also contained 1.5% phospholipid. However, caution needs to be exercised because of an unexplained poor growth of the lobsters in the experiment. An 1-week depletion and 9-week repletion cholesterol experiment with juvenile (~0.5 - 3.5 g) lobsters has just terminated (December 2006). Lobsters were fed the same formulations as used in the sub-adult study except that the TG-diets were fed three times daily (AM, PM and midnight). Although the data analysis of the experiment is incomplete, the growth of the lobsters was excellent with the best growth (1 g/week) occurring on the 0.45% cholesterol diet and this appears to be better than lobsters fed a control diet of fresh mussel/fish/shrimp (0.8 g/week). The overall survival rate was 67% but this was markedly affected by the initial size of the lobsters, only 43% for lobsters < 0.5 g and 90% for lobsters of >3 g. Survival rate was worst for the 0.15% cholesterol diet (52%) with all other diets having lobster survival rates ranging from 60 to 76%.
Land-based systems for lobster culture:
More than 500 recently settled P. ornatus lobsters were collected from Trinity Inlet, Cairns by QDPIF staff in September and October 2006. This enabled research with juvenile lobsters to be carried out at the QDPIF's and CSIRO's laboratories. At QDPIF's Northern Fisheries Centre, a series of experiments was carried out to investigate different feeding schedules on growth and survival of the lobsters. Feeding lobsters continuously during the night did not improve growth or survival of lobsters given single meals at dusk and again in the morning. The main food used in the experiment was a commercial kuruma (Penaeus japonicus) shrimp pellet and losses due to cannibalism were high, with survival rate averaging 62% after 1-month culture. Another experiment is examining the importance of timing of feeding and specifically testing whether it is better to provide a single meal of fresh mussel in the morning or at dusk, the latter more closely mimicking natural peak feeding activity.
Year Three Progress summary
Ecological impact of lobster seed collection in Viet Nam
ION has completed the annual census of lobster seed collection for the 06/07 settlement year in Vietnam. The survey collected data from 94 local dealers and 31 lobster farming villages, encompassing eight central coastal Provinces from Da Nang in the north to Binh Thuan in the south. The census was thought to represent about 95% of the total Vietnamese lobster seed catch for aquaculture grow-out. Settlement of Panulirus ornatus lobster seed was poor this year with a total of 999 thousand seed being caught compared to 1.92 million in 05/06. Because of the scarcity of P. ornatus, the lower value P. homarus was kept with 1.33 million being taken. In previous years, this species was usually discarded. P. ornatus catches were highest in Binh Dinh (280 thousand) and Da Nang (200 thousand) Provinces; P. homarus was most abundant in the southerly Provinces of Ninh Thuan (288 thousand) and Binh Thuan (326 thousand). Whether or not the low settlement of P. ornatus seed is a consequence of continued heavy exploitation of the species is not known. Lobster settlement can be quite variable from one year to the next
Reducing post-capture losses of seed lobsters
Experiments examining the effects of stocking density, initial holding time, subsequent transport time and feed type on growth and survival of seed lobsters from time of catch through to 90 days of nursery culture have been carried out by RIA3. The results indicated that within the bounds of current commercial practices, stocking density and initial land-based holding time had only slight effects on subsequent growth and survival of the lobsters. However, increasing transport time from 1 to 6 or 12 hours had a profound adverse effect on survival rate, which often was apparent only after 30 days of nursery culture. Improved transport methods are currently being compared to find better methods that reduce the stress on the lobsters during transport. Four different 6-h transport conditions (static, normal aeration with or without shelter and compressed air without shelter) have resulted in 100% survival after transport. Results of the subsequent nursery rearing stage are being compiled.
Husbandry best-practices for lobster grow-out
Improved and less-polluting methods for seacage grow-out of lobsters
An experiment commenced March 2006 comparing traditional lobster culture methods (trash fish feeding) with one in which green mussels (Perna virdis) and lobsters are being co-cultured is nearing completion. The study is centred on four cage sites in Van Phong Bay (Khanh Hoa Province) where water column and sediment environmental conditions (chemical and microbiological) and lobster productivity are being measured. After 16 months of culture, feeding trash fish or trash fish plus mussel appears to have had no effect on survival or growth of the lobsters. However, two of the sites are showing higher lobster growth but this appears to be unrelated to mussel co-culture. Some site-specific environmental differences are being observed, both within and between sampling times (October 06 and May 07), but these cannot be attributed to the imposed experimental conditions. Effects of season, river inflow and other land and cage pollutants are thought to be having as great, if not greater, effect on the environmental conditions at the cage sites. Heavy metal analysis of mussels and lobsters has recorded levels below the maximums set for seafood safety. Vibrio and fecal coliform counts have been high and universally present in the water column, sediment and mussel (Vibrio only), no pathogenic bacteria have been found in any of the lobster samples.
Improving lobster grow-out feeds
In Vietnam, NTU is investigating ways of optimizing the utilization of trash fish, both to maximize growth and survival of the lobsters and also to reduce the environmental impact of this type of feeding. In the first of two 8-week growth assay experiments, three different types of trash fish (lizard, bream or anchovy) and two vitamin supplementation levels (with or without vitamin premix) were examined factorially when given as a moist noodle feed. Vitamin supplementation significantly improved lobster growth and lizard fish was superior to the other two fish species. In the second experiment, the effectiveness of three different binders - Magicoh (an urea-formaldehyde binder), TG and an undisclosed USA binder - were evaluated. Water stability of the semi-moist pellets was best for the TG-bound diets while lobster growth rate was significantly inferior with diets bound using the USA binder.
At CMAR, the apparent nutrient and energy digestibility of eight key dry feed ingredients for diet development - Chilean fish meal, Antarctic krill meal, NZ mussel meal, lango crustacean meal, Japanese squid meal, dehulled narrow-leaf lupin, solvent-extracted soybean meal and wheat - have been determined. Apart from an unexpectedly low digestibility of the squid meal, the digestibility of all other test ingredients was similar to that observed for other decapod crustaceans. The main focus of CMAR research has been to determine the dietary cholesterol requirement of sub-adult (600-700 g) and juvenile (~0.5-3.5 g) lobsters. Based on cholesterol content of the digestive gland, a dietary cholesterol level of 0.35% was sufficient for sub-adult lobsters when the diet also contained 1.5% phospholipid. In the juvenile lobster experiment, excellent growth of around 1 g/week was observed for lobsters fed the pelleted diets compared to 0.8 g/week for those fed a control diet of fresh mussel/fish/shrimp. Lobster body cholesterol and growth increased slightly and linearly with increasing dietary cholesterol level up to the maximum examined of 0.45%. The overall survival was 67% but this was markedly affected by the initial size of the lobsters, only 43% for lobsters < 0.5 g and 90% for lobsters of >3 g. Survival rate was worst for the 0.15% cholesterol diet (52%) with a range of 60 to 76% for all other diets.
Land-based systems for lobster culture
More than 500 recently settled P. ornatus lobsters were collected from Trinity Inlet, Cairns by QDPIF staff in September and October 2006. At QDPIF's Northern Fisheries Centre, a series of four experiments has been carried out to investigate different feeding schedules on growth and survival of the lobsters. Feeding lobsters continuously during the night did not improve growth or survival of lobsters given single meals at dusk and again in the morning. The main food used in the experiments was a commercial kuruma (Penaeus japonicus) shrimp pellet and losses due to cannibalism were high, with survival rate averaging 62% after 1-month culture.
Year Four Ecological impact of lobster seed collection in Viet Nam
Comparison of the catch data for years 05/06 and 06/07 shows some interesting differences: total catch of P. ornatus seed in 06/07 was only half that of the 05/06 season (999k vs 1,918k respectively); whereas P. homarus was only a minor catch in 05/06, more of this species was caught in 06/07 than P. ornatus (1,329k vs 999k, respectively); and the highest monthly catch was delayed by one month in 06/07, being highest between October and February. The 07/08 census of ION has completed the annual census of lobster seed collection for the 06/07 settlement year in Vietnam is awaiting collation and analysis of the May 08 survey data.. This year, 101 dealers in the eight coastal central provinces and more than 30 lobster farming villages are providing catch data. The number of seed lobsters caught in 07/08 is expected to be low because demand for the seed has fallen as a result of the current severe lobster disease problems in Vietnam. Farmers are unwilling to take the risk of huge disease losses and are choosing to culture marine finfish instead of lobsters. It is reliably estimated that the number of fishing boats catching lobster seed this year is only 60% of that for the previous season. Consequently, the price of P. ornatus seed has dropped to only 55-65,000 VND (AUD$3.5-4.2) compared to prices of 100-115,000 VDN (AUD$10-11) in 05/06 and 175-185,000 VDN (AUD$15-16) in 06/07. The survey collected data from 94 local dealers and 31 lobster farming villages, encompassing eight central coastal Provinces from Da Nang in the north to Binh Thuan in the south. The census was thought to represent about 95% of the total Vietnamese lobster seed catch for aquaculture grow-out. Settlement of Panulirus ornatus lobster seed was poor this year with a total of 999 thousand seed being caught compared to 1.92 million in 05/06. Because of the scarcity of P. ornatus, the lower value P. homarus was kept with 1.33 million being taken. In previous years, this species was usually discarded. P. ornatus catches were highest in Binh Dinh (280 thousand) and Da Nang (200 thousand) Provinces; P. homarus was most abundant in the southerly Provinces of Ninh Thuan (288 thousand) and Binh Thuan (326 thousand). Whether or not the low settlement of P. ornatus seed is a consequence of continued heavy exploitation of the species is not known. Lobster settlement can be quite variable from one year to the next
Reducing post-capture losses of seed lobsters
RIA3 has continued studies to examine the role of transport and nursery cage practices on the growth and survival of seed lobsters. Seed caught at Hue was transported for 12 hours and then distributed to submerged nursery cages, either with or without net shelters and with supplemental aeration for a 30-day culture period. Survival during transport was 100% and after 30-day nursery culture was also very high, 97.2% for cages with shelters and 96.0% for those without shelters; lobster growth was also slightly better for cages with shelters. Nursery survival of seed lobsters subjected to 6- or 12-h transport in previous year's studies has varied from 22 to 100%, demonstrating the extreme variability in lobster seed survival. This variability is most likely due to the condition of the seed at capture (seasonality and seed vitality) but could also be exasperated by the environmental conditions under which the seed is held prior to, during or after transport. Experiments examining the effects of stocking density, initial holding time, subsequent transport time and feed type on growth and survival of seed lobsters from time of catch through to 90 days of nursery culture have been carried out by RIA3. The results indicated that within the bounds of current commercial practices, stocking density and initial land-based holding time had only slight effects on subsequent growth and survival of the lobsters. However, increasing transport time from 1 to 6 or 12 hours had a profound adverse effect on survival rate, which often was apparent only after 30 days of nursery culture. Improved transport methods are currently being compared to find better methods that reduce the stress on the lobsters during transport. Four different 6-h transport conditions (static, normal aeration with or without shelter and compressed air without shelter) have resulted in 100% survival after transport. Results of the subsequent nursery rearing stage are being compiled.A detailed survey of the environmental conditions that the seed lobsters are being subjected to by the various fishermen is being conducted to help identify best practices. Additional work on optimizing husbandry practices during nursery culture (first 30 days post catch of seed) has commenced. The first experiment is examining the effects of different types of shelters (nil, drilled wood, drilled coral or net bunch) in the cages with all treatments being fed the same mixture of trash fish and shellfish. Subsequent experiments will examine different feed types and feed timing and frequency.
Husbandry best-practices for lobster grow-out
Improved and less-polluting methods for seacage grow-out of lobsters
An 18-month experiment commenced March 2006 comparing traditional lobster culture methods (trash fish feeding) with one in which green mussels (Perna virdis) and lobsters are being co-cultured is has been completed.nearing completion. The study is centredentailed on four cage sites in Nha Phu BayVan Phong Bay, ( Khanh Hoa Province, (2 near-shore and 2 off-shore sites with mussel co-culture at one of the sites at each location in combination with the feeding of only trash fish or trash fish and mussel)). where wWater column and sediment environmental conditions (chemical and microbiological) and lobster productivity traits are werebeing measured over the course of the experiment. There was increased mortality of the lobsters after the 13 month of the experiment because of a new disease outbreak (locally called milky disease) that has become widespread in cultured lobsters in Vietnam. The disease is thought to be caused by a Rickettsia-like bacteria. Losses were highest (25-35%) at cage sites where only trash fish was fed and generally lower (2-10%) at the off-shore sites. After 16 months of culture, feeding trash fish or trash fish plus mussel appears to have had no effect on survival or growth of the lobsters. However, two of the sites are showing higher lobster growth but this appears to be unrelated to mussel co-culture. For the whole experiment, lobster survival was only 43.5%. Although firm conclusions can not be drawn because of the low treatment replication and disease, there was some indication that lobsters fed trash fish with mussels grew and survived better than those fed only trash fish. Some site-specific environmental differences are beingwere observed, both within and between sampling times (May and October 06; April and August 07 and May 07), but these cannot be attributed to the imposed experimental conditions. Effects of season, river inflow and other land and cage pollutants are thought to be having as great, if not greater, effect on the environmental conditions at the cage sites. Heavy metal analysis of mussels and lobsters has recorded levels below the maximums set for seafood safety. Vibrio and fecal coliform counts have been high and universally present in the water column, sediment and mussel (Vibrio only), no pathogenic bacteria have been found in any of the lobster samples. Again there was some indication that culturing mussels alongside the lobster cages improved the environmental conditions adjacent to the cages. Widespread adoption of this practice could help ameliorate the poor water quality in Van Phong Bay.
Improving lobster grow-out feeds
During the year, work at NTU focused on examining the In extent to which fish meal in a compounded diet can be replaced using soybean meal. In the experiment with juvenile P. ornatus lobsters, fish meal was serially replaced with soybean meal (5 diets with soybean meal included at 0 to 30%) on an iso-protein and iso-lipid basis. An additional 'control' diet of trash fish was included in the 10-week growth assay experiment. Inclusion of soybean meal in the diet brought about an almost linear decline in growth rate of the lobsters (235 to 119% gain) and a concomitant worsening of food conversion ratio (from 1.7 to 2.9) By comparison, lobsters fed the trash fish control diet grew the best (273% gain) at an economical DM food conversion of 1.4. Clearly, replacement of fish meal with soybean meal was not well utilised by the lobsters. In further work, the lobster's requirement for the highly unsaturated omega-3 essential fatty acids is being investigated in a 10-week growth assay experiment with juvenile lobsters. Vietnam, NTU is investigating ways of optimizing the utilization of trash fish, both to maximize growth and survival of the lobsters and also to reduce the environmental impact of this type of feeding. In the first of two 8-week growth assay experiments, three different types of trash fish (lizard, bream or anchovy) and two vitamin supplementation levels (with or without vitamin premix) were examined factorially when given as a moist noodle feed. Vitamin supplementation significantly improved lobster growth and lizard fish was superior to the other two fish species. In the second experiment, the effectiveness of three different binders - Magicoh (an urea-formaldehyde binder), TG and an undisclosed USA binder - were evaluated. Water stability of the semi-moist pellets was best for the TG-bound diets while lobster growth rate was significantly inferior with diets bound using the USA binder.An EPA and DHA-enriched oil is being serially added to a basal low omega-3 diet to provide an EPA + DHA content ranging from 1.6 to 2.1% while maintaining constant levels of total lipid and other essential fatty acids. Lobster productivity was markedly improved as the EPA/DHA content of the diet increased from 1.5 to 1.8% but further enrichment to 2.1% was without effect. The result is in line with research with other crustacean decapods indicating a high dietary requirement for these essential fatty acids.
At An 8-week experiment at CSIRO has examined optimal tank water depth for nutritional studies with sub-adult (>600 g) lobsters. In the experiment, three different tank types and stocking rate were tested: (a) 2 m diameter, 2-tonne tank with an effective water depth of 750 mm and stocked with 3 lobsters (1 lobster m2); (b) clear bottom, 1.5 x 0.6 m rectangular tank (400 L) with an effective water depth of 350 mm and stocked with 2 lobsters (2 lobsters m2); and (c) clear bottom, 0.75 m diameter tank (200 L) with an effective water depth of 500 mm and stocked with 1 lobster (2 lobsters m2). Eight replications were used to provide good statistical power. There was a very clear advantage with lobsters held in the 2-tonne tank growing at 9-10 g/week compared to only 5.7 to 6.0 g/week for the other two tank types. The lobsters were fed a dry TG-bound diet and the recorded growth rate for lobsters in the 2-tonne tank was as good as that achieved by lobsters cultured in sea cages in Vietnam and fed trash fish.
Also at CMARCSIRO, a 12-week sub-adult lobster experiment is examining the essentiality of including fresh constituents (fish fillet) in diets presented either as moist or dry pellets. The experiment was delayed on account of the purchased lobsters being of poor quality because of sub-optimal water quality in the supplier's holding tanksthe apparent nutrient and energy digestibility of eight key dry feed ingredients for diet development - Chilean fish meal, Antarctic krill meal, NZ mussel meal, lango crustacean meal, Japanese squid meal , The experiment is now in progress with lobsters stocked in sand-bottom 2.5 tonne tanks (4/tank) dehulled narrow-leaf lupin, solvent-extracted soybean meal and wheat - have been determined. Apart from an unexpectedly low digestibility of the squid meal, the digestibility of all other test ingredients was similar to that observed for other decapod crustaceans. The main focus of CMAR research has been to determine the dietary cholesterol requirement of sub-adult (600-700 g) and juvenile (~0.5-3.5 g) lobsters. Based on cholesterol content of the digestive gland, a dietary cholesterol level of 0.35% was sufficient for sub-adult lobsters when the diet also contained 1.5% phospholipid. In the juvenile lobster experiment, excellent growth of around 1 g/week was observed for lobsters fed the pelleted diets compared to 0.8 g/week for those fed a control diet of fresh mussel/fish/shrimp. Lobster body cholesterol and growth increased slightly and linearly with increasing dietary cholesterol level up to the maximum examined of 0.45%. The overall survival was 67% but this was markedly affected by the initial size of the lobsters, only 43% for lobsters < 0.5 g and 90% for lobsters of >3 g. Survival rate was worst for the 0.15% cholesterol diet (52%) with a range of 60 to 76% for all other diets.
Land-based systems for lobster culture
At QDPIF, the low settlement of seed lobsters limited juvenile lobster work to a 12-week tank study examining the suitability of a moist diet. The growth of the lobsters was good (daily growth coefficient ranging from 0.7 to 1.6%), survival was also high (69%) and the vitality and coloration were excellent. The moist diet was expensive (AUD$9-10/kg) and further work is being done to source cheaper ingredients. Additionally a 4-month pond trial with sub-adult lobsters confined in cages in the intake channel of a prawn farm was carried out and compared with lobsters held in a land-based tank. Lobsters were stocked 20/cage of dimensions 1.6 m x 1.6 m and a depth of 1 m. All lobsters were fed the newly developed moist diet with excellent growth (daily growth coefficient of 0.4-0.5%) andMore than 500 recently settled P. ornatus lobsters were collected from Trinity Inlet, Cairns by QDPIF staff in September and October 2006. At QDPIF's Northern Fisheries Centre, a series of four experiments has been carried out to investigate different feeding schedules on growth and survival of the lobsters. Feeding lobsters continuously during the night did not improve growth or survival of lobsters given single meals at dusk and again in the morning. The main food used in the experiments was a commercial kuruma (Penaeus japonicus) shrimp pellet and losses due to cannibalism were high, with survival rate averaging 62% after 1-month culture survival (75-93%). The coloration of the lobsters was similar to wild-caught lobsters and achieved high prices when marketed.
SMAR Variation to include Nusa Tengara Barat (Lombok) and Nusa Tenggara Timut (Flores, East Timor), Indonesia
In November 2006, representatives of the Smallholder Agribusiness Development Initiative (SADI) convened a workshop with Indonesian participants to identify priorities for market chain work in eastern Indonesia. One such priority was to improve lobster grow-out and nutrition in NTB (Lombok and Sumbawa). Subsequently, a priority for lobster aquaculture development has been identified for NTT (Flores, Sumba and West Timor). Because similar work on lobster aquaculture was already being carried out in Vietnam and Australia in the ACIAR Fisheries project FIS/2001/058, one of the Project's Australian scientific team (Dr Clive Jones, QDPIF) was commissioned in April 2007 to carry out a feasibility study of the lobster aquaculture industry in NTB. The prime objectives of the study were to identify opportunities and constraints for lobster aquaculture development in NTB and to consider whether synergies might exist between the needs of the Vietnam and NTB lobster aquaculture industries and the work being done in the existing ACIAR lobster project. The feasibility study was undertaken as a Support for Market-driven Adaptive Research (SMAR) initiative and administered as a variation to FIS/2001/058. The feasibility study noted the fledgling state of lobster aquaculture development in NTB, which was paralleling the development that occurred 10 years earlier in Vietnam, and commented on the significant opportunity that existed to expand smallholder industry development, partially through lobster aquaculture technology transfer from Vietnam and through targeted market driven adaptive research at NTB.
The results and recommendations arising from the feasibility study resulted in the development of an expanded joint ACIAR Fisheries and SMAR Variation so that lobster aquaculture development in NTB and NTT could be fast-tracked. The following sections outline the proposed work to be done in the Variation. The variation also sought to slightly increase the budget being provided to the Vietnamese agencies to address the increased cost of purchasing lobster seed for research and the higher than budgeted cost of carrying out the annual census of lobster seed being taken from the wild for aquaculture.
Carry out a market chain assessment of lobster supply and demand in Indonesia and Vietnam
The global demand for lobster is growing by approximately 15% p.a. The increased demand is being driven by the international market, particularly China, which for Indonesia is being serviced by trading locations in Bali and Surabaya. This demand is most significant for the tropical rock lobster, P. ornatus, known in Indonesia as Pearl Lobster. Marketable lobsters are sold to middleman who transport them in small quantities (20 - 50 kg) from the village to Mataram (capital city of NTB) and who organise air transport to exporters in Bali. Price paid to farmer is around IDR 150,000 (AUD$16.80) for 250-300 g P. homarus and IDR 130,000 (AUD$14.60) for 300-500 g P. ornatus. Marketable lobster production from aquaculture industry is still low. Exporters pay a lower price for farmed lobster than for a wild caught. This is primarily because supply volume is small and inconsistent, and farmed lobster are considered to be pale in colour and of weak vigour, which impacts significantly their suitability for transport live to markets in Taiwan and China. Market demand for lobster is significant and increasing. Prices paid to exporters are very attractive; for P. ornatus over IDR 350,000 (AUD$40) per kg for large lobsters above 1 kg. P. homarus also fetch high export price. Exporters would readily accept increased supply of aquaculture lobsters of the high value species.
Facilitate development of lobster aquaculture at NTB and NTT
Project technology and lobster farming method have been transferred by reciprocal meetings and field trips in Vietnam (January 2008) and in Indonesia (March 2008). All agencies have participated in this exchange. As a first step in the technology transfer, three personnel from Indonesia were identified for travel to Vietnam to meet with the existing project staff, be informed of the lobster farming industry and the outcomes of the ACIAR project to date, and to specifically examine the various sectors of the industry in Vietnam via field trips. Visits were made to NTU, ION and RIA3 to have discussions with project staff to discuss issues specific to their Agency and to enable the Indonesian contingent to view research being carried out. Brief meetings took place at each of NTU, ION and RIA3 to show Indonesians the facilities, reiterate the role of each agency in the project and discuss the Indonesian components and future planning. At RIA 3, catching methods, holding and transport of lobster seed were discussed. It appears that the method known as light nets for which a floating net is suspended between two boats with bright lights attached is of diminishing prevalence. On the following days, field trips were arranged so that the Indonesian contingent could see first hand all aspects of lobster aquaculture in Vietnam. Locations visited included lobster farms, fish landing market, and puerulus catching area of Nha Trang Bay. Field visits were also made to middleman and puerulus catching area at Cat Loi village, northern Nha Trang.
Training of NTB and NTT staff in lobster aquaculture husbandry - lobster feeds, nursery and grow out
The feasibility study identified several major aspects of lobster aquaculture at Lombok that was significantly reducing productivity and profitability:
Survival of lobsters from puerulus to 20 mm juvenile size appears to be in the order of 40-50% and this is similar to what occurs in the Vietnamese lobster industry.
Cultured lobsters were pale and lacked vitality. Buyers pay much less for lobsters cultured at Lombok than those of a similar size from the wild. Possibly because of slow growth, cultured lobsters at Lombok are marketed at a small size, less than 500 g, which attract a much lower price per kg than the market-preferred size of 1-1.2 kg. Improving the feed and feeding practices could dramatically increase lobster growth rate and condition, thereby markedly improving production and profits; and
The feasibility study noted high variability in cage specification and grow-out methods, and clearly identified deficiencies relative to the proven methods of Vietnam. Optimising cages and husbandry practices at NTB and NTT would contribute to increased growth and survival, and thus a more profitable aquaculture industry for small-holder farmers.
The above issues could speedily be addressed by providing two staged training activities for NTB and NTT staff: (i) a dedicated training activity to impart Australian knowledge in lobster feed development and lobster culture practices; and (ii) a follow-on training activity in which staff at MADC would undertake low-key but supervised research to see the benefits of alternative husbandry practices (traditional versus improved culture methods). Successful adoption of the 'new' culture methods will require MADC staff to actively extend the results of their work to the local small-holder farmers at NTB and NTT by way of meetings and site visits. These training activities at Lombok will be conducted in early June 2008.
Assess the ecological impact of lobster seed collection at NTB and NTT
Survey lobster settlement sites at NTB and NTT
Existing lobster aquaculture at NTB has developed from opportunistic sighting and collection of lobster seed that have settled on sea cages or recovered as an incidental catch from bagang fish traps. Juvenile lobsters are frequently observed settling on the floats and cages of the existing aquaculture facilities and are captured and cultured to a marketable size. This development began in 2000 and has now expanded to encompass several villages and around 250 cages. Two species are cultured, the sand lobster, P. homarus known locally as pasir, and the pearl lobster, P. ornatus known as mutiara. Lobster seed collected includes both the swimming post-larval stage (puerulus), and more advanced juveniles which are found attached to substrates. Methods include use of fish traps, shelter traps, netting and manual collection from existing cage structures. This survey is designed to assess the size of the lobster seed resource at NTB by the application of standardised seed collectors, deployed at locations within the existing seed collecting areas and in currently unfished areas that might support further development. The objective of the survey is to establish baseline seed catch data for areas of eastern Lombok. The survey will employ a light trap collector of a design equivalent to those used in Vietnam. Four collectors will be deployed at each of 10 locations, such that they represent 4 replicates to ensure robust data are collected. Each trap consists of a bamboo framed tripod mounted on styrofoam floats. From the apex of the tripod, a kerosene lantern will be secured, as the light source. From each of the three corners of the frame, two trap types will be suspended. The first one will consist of a bundle of netting of consistent size and form, weighted to ensure it remains submerged. The second one will consist of a timber pole of approximately 1 m length and 100 mm diameter, in which 50 x 10 mm diameter holes will be drilled at regular intervals. Thus each trap will have 6 shelters in which lobster seed might settle. The survey will commence in April 2008 and will continue for one year. Survey/feasibility study for settlement sites at NTT / Flores has been inspected by CSIRO, QDPI&F and MADC staff during a visit in March/April 2008. At Flores, lobster seed collectors will be placed along the south coast while sea cages for lobster grow-out might be better sited along the north coast.
Annual census of lobster seed collection at NTB and NTT
Accurate information on the number of lobster seed being caught from the wild for aquaculture is critical for determining the magnitude of exploitation and to provide a framework should it be necessary to implement quotas or other management practices to safeguard the sustainability of the wild resource. This will require the cooperation of lobster farmers (and those fishermen that subsequently target the catch of lobster seed for on-selling to farmers) to provide accurate data. The process would involve MADC project staff interviewing all known lobster farmers and seed merchants and putting in place a daily log book system to record numbers of lobsters entering and leaving the farm system. Lobster seed census will be carried out in 3 coastal locations, south-central and south east of Lombok Island. Data on lobster seed catches of P. ornatus and P. homarus will be calculated from daily logbook of each farmer recorded by one dealer at each fishing locations. Total catch in each location and over all catch sites will be calculated. Daily catch will be calculated by total month catch divided by number of farmers and total days in a month. Monthly catch will be calculated by total amount of seeds on October 2007 up to May 2008. Data collected from all of lobster farmers (291 persons) in around 3 locations will be surveyed from October 2007 up to May 2008. Total catch of lobster seeds until February 2008 was 78,056 P. homarus and 23,158 P. ornatus and 2,403 other species. P. homarus was the most dominant species.
|