Collaboration for Agriculture & Rural Development:" Development of clam culture for improvement and diversification of livelihoods of the poor coastal communities in Central Vietnam - MS04 " potx

The key highlights include:  clam culture in ponds production experiments involving prawn farm effluent and influent have been completed;  clam and prawn polyculture experiments were c

Ministry of Agriculture & Rural Development

Collaboration for Agriculture & Rural Development

(CARD)

027/05VIE

Development of clam culture for improvement and diversification of livelihoods of the poor coastal communities in Central Vietnam

Oct, 2006 – Mar, 2007

5.3 Capacity Building 24

5.3.1 ARSINC _ 24 5.3.2 End-users _ 24 5.3.3 Enhanced reputation and relation ship with other institutions and collaborators 24

5.3 Publicity 24 5.4 Project Management 24

6 Report on Cross-Cutting Issues 25

6.1 Environment Environment _ 25 6.2 Gender and Social Issues 25

7 Implementation & Sustainability Issues _ 25

7.1 Issues and Constraints _ 25 7.2 Options _ 25 7.3 Sustainability 25

8 Next Critical Steps 25

9 Conclusion 26

10 Statuatory Declaration _ 26

1 Institute Information

and diversification of livelihoods of the poor coastal communities in Central Vietnam

(Project No: 027/05VIE)

Vietnamese Institution Aquaculture Research Sub-Institution for North

Central (ARSINC)

Vietnamese Project Team Leader Mr Nhu Van Can (Project Director)

Mr Chu Chi Thiet (Project Manager)

Australian Organisation South Australian Research and Development

Institution (SARDI)

Dr Bennan Chen (Senior Scientist)

Completion date (revised)

Contact Officer(s)

In Australia: Team Leader

Name: Dr Martin Kumar Telephone: 08 82075 400

Position: Principal Scientist, and Program

Leader, Integrated Biosystems Integrated Resource Management and Biotechnology

Fax: 08 82075481

Organisation South Australian Research and

Development Institution (SARDI)

Organisation Aquaculture Research Institute for

North-Central

Central provinces and to develop a strategy which contributes to sustainable aquatic

environment management using clam aquaculture to improve prawn farm effluent

utilisation Significant progress has been made in this section Key findings are listed

below

 Clam production can be successfully undertaken in ponds Currently clam culture is practiced in inter-tidal area

 The preferred substrate for clam culture is clay-sandy

 The clam cultured at lower density (90 ind./m2) showed faster growth rate

The size of clam determines the market price Price of the clam greatly influences the economics of the clam culture Therefore, it is important consider the growth rate and the culture duration available for each type of culture practice before deciding appropriate stocking density and size of the clam for initial stocking In relation to hatchery spat production, a major upgrading of hatchery facility has been undertaken at ARSINC which improved production of live feed clam larval rearing Presently the facility provides stable

output of at least 4 marine algal species: Nanochloropsis, Isocrysis, Tetraselmis and Chaetoceros and ready for next breeding season

3.1 Project Implementation Progress

3 1.1 Key Highlights

Project progressed well during the first year and achieved specified milestones related

technology development in clam husbandry (production) and hatchery areas

Following milestone reports submitted were reviewed and accepted

 Socio-economic evaluation report

 First six monthly report

In accordance with the proposal the first year work was focussed on technology development through adaptive research in hatchery and husbandry technology The key highlights include:

 clam culture in ponds (production) experiments involving prawn farm effluent and influent have been completed;

 clam and prawn polyculture experiments were completed;

 trial on clam culture in the inter-tidal has been just concluded and data analysis being carried out; and

 experiments on clam cultured as alternative crop is also just concluded and data

analysis being carried out

 hatchery infrastructure upgraded (including live feed production) for spat production trials and trials are progressing well

 training course including study tour in SARDI, Australia for key staff of ARSINC and representatives of local government satff has been conducted

In the second year, the work will be concentrated on farm trials, which fine tune the

technology and facilitate formulation of extension manuals A Farmer selection criterion was developed in consultation with lead farmers, village representatives and provincial

authorities The details will be reported in the next report In the third year, work will focus

on extension of technology including expanded farmer participated trials Project impact will also be assessed during the third year

3.1.2 Key outcome

a) Production experiments made excellent progress

Significant progress has been made in this component of the project Results from production experiment indicated that clam can be successfully cultured in ponds The results also

provide suggestions for appropriate stocking density and substrata to maximize growth and production of clam culture in ponds Key findings are listed below

 Clam production can be successfully undertaken in ponds Currently clam culture is practiced in inter-tidal area Our experiments proved that clam culture could be expanded and pond system could be utilised for successful operation

 Clam can be cultured in three kind of substrate including clay, sandy and clay-sandy substrate However, the preferred substrate is clay-sandy especially in effluent pond system

 The clam cultured at lower density (90 ind./m2) showed faster growth rate compared to higher density (120 ind./m2) in influent system However, the growth of clam likely to be

2

 The size of clam determines the market price Price of the clam greatly influences the economics of the clam culture Therefore, it is important consider the growth rate and the culture duration available for each type of culture practice before deciding appropriate stocking density and size of the clam for initial stocking

b) Upgrading facility and improve live feed production for hatchery production experiments

Based on the previous results from hatchery experiments last year, and recommendation from the first report, food and feeding ( algae) were regarded as major factor that might influence the spat production (please refer to the 1st six monthly report) Effort on production of algae

resulted in stable output for at least 4 marine algal species: Nanochloropsis, Isocrysis,

Tetraselmis and Chaetoceros Further more, the infrastructure for the spat production have

been improved and ready for the next breeding season

Overall the project is progressing well as per the proposal

4 Introduction & Background

A summary of the project objective, outputs expected and approach and methodology

The main objective is to develop and extend the clam culture technology (hatchery and husbandry) to sustain livelihoods of poor coastal farmers in the North Central provinces; and

to develop a strategy which contributes to sustainable aquatic environment management using clam aquaculture to improve prawn farm effluent utilisation The aims of the proposed project are:

a) to provide poor fisher community an alternative income, food security;

b) to improve technological and extension capacity for the stakeholders; and

c) to reduce negative impacts of shrimp culture through implementation of a strategy for environmental management and waste utilisation of existing resources

4.1 Specific objectives:

The objectives of this project (027/05VIE) include the following:

 to develop and extend the clam culture technology (hatchery and husbandry);

 to sustain livelihoods of poor coastal farmers in the North Central provinces; and

 to develop a strategy which contributes to sustainable aquatic environment management using clam aquaculture to improve prawn farm effluent utilization

4.2 Outputs Expected

In accordance with expected output proposed, the last six months were focused on following aspects related to achieving the development of clam production technology The log frame reference is provided in the appendix A

 Complete experiments of clam culture in the influent, effluent system and polyculture of clam with shrimp in ponds

 Establish and operate the experiment on clam culture as alternative crop of shrimp culture

in ponds

 Establish and operate the experiment on clam culture in the inter-tidal areas

 Improve algae production for the next breeding season

 Above mentioned activities were completed as per the proposed log frame

4.3 Methodology

The visits by Australian Project Leader and scientists (August 2006, December 2006 and April 2007) enabled to undertake major review of the project methodology, implementation strategy and resource and progress evaluation Scientific approach has been refined for implementing appropriate methodology for the experiments related to both clam husbandry and hatchery As a result of these steps (ref:1st six monthly report) , it was possible to incorporate information from preliminary research results into the following experimental design; clear scientific comparisons are possible; avoiding duplication of activities; and efficient usage of resources

5 Progress to Date

5.1 Implementation Highlights

Note: Detailed implementation progress is recorded in attached Progress Report Logframe This format is provided as a guide The main purpose of progress reports is to report against the achievement of the activities detailed in the project proposal logframe

5.1.1 Clam production (Grow-out trials)

The research in pond culture type will be focused on suitability of substrate, optimum stocking density, and stocking size All experiments were conducted in triplicate The outcome of the experiments (culture types) will be used for the development of technical guidelines for on farm trials in the second year The clam production involved the following

5 types culture trials

a) Clam culture using prawn farm influent water (reservoir): Clam culture will be carried out as a pre- treatment for water intake in prawn farm- completed

b) Clam culture using prawn farm effluent (effluent treatment pond) Clam farm will be utilised as effluent treatment pond The expected outcome is a good strategy on management practices for shrimp ponds and clam culture- completed

c) Shrimp and clam polyculture: Simultaneous culture of prawn and clams will be undertaken with a view to improve farm water quality as well as generate additional income- completed

d) Alternative/rotation crop: Clam culture will be under taken after the pawn harvest as rotational – progressing well

e) Clam culture in intertidal area: Inter tidal area will be divided into three zones based

on the tidal influence for clam culture- progressing well

Trials related to a, b, and c are completed Clam culture on inter-tidal area and prawn pond (rotational/alternative crop) are progressing well

5.1.1.1 Experiment on clam culture in prawn farm influent and effluent

The main aim of this experiment is develop a method of clam culture in ponds using prawn influent and effluent The objectives of the trial are to:

 To determine suitable substrate for optimising the clam biomass( production)

 To determine optimum density for optimising the clam biomass (production)

Clam culture has been mainly carried out in the inter-tidal area In order to develop and expand clam culture as a viable farming industry it is necessary to develop pond culture technology There is also a need to transform the existing prawn farming to more environmentally sustainable by utilising the effluent which causes aquatic pollution

Materials and method

A pond culture system using effluent from prawn farm has been established for this experiment for two treatments – bottom (substrate) and stocking density The trial conducted

at Thanh Hoa Province included 18 ponds of 9 m2 9 plots were used for bottom treatment: sand bottom, clay-sand bottom and clay bottom with stocking density of 90 pieces/ m2 in the replication of 3 Other 9 sandy-bed ponds for treatment of density in the same replication including: 90 clams/m2, 120 clams/m2 and 150 clams/ m2

A similar experimental design was used for influent water Environment parameters such as

DO, water temperature, pH, N-NH3, turbidity as well as zoobenthod were periodically

monitored and registered Clams were randomly sampled (30 individuals for each pond) for growth evaluation The experiments were terminated after 120 day rearing All data of the treatments were tested for significant differences (P<0.05) using One-way ANOVA followed

by Turkey test for multiple comparisons of means The data are expressed as Mean ± SD and statistical analysed was performed using Graphpad Prism version 4.0 and Microsoft Office EXCEL Specific growth rated were calculated using following formula, SGR=100*Ln(W)-Ln(Wo)/t where W is the final weight, Wo is the stocking weight and t is the experimental duration (day) It is similar calculation to the case of length

Results and discussions

The result clearly indicated that the clay-sandy substrata produced higher survival rate and total biomass compared to sandy or clay substrate (P<0.05) Clay –sandy is the preferred substrate for clam(P<0.05) A detailed profile of the actual percentage of sand and clay and physical characters are being gathered and will be provided in the next report A mixture of conditions prevailing in sand and clay may allow optimum moisture, air and produce unique ecological condition provides optimum environmental conditions for clam survival and growth ( Table 1 and Figure 3: a, b,c&d)

Fig 1 Effluent pond system Fig 2 Influent pond system

Table1 Survival and biomass of clam cultured in different substrata

Biomas (kg/m2) 0.69±0.04 0.64±0.02 0.81±0.05

Fig 3 ( a,b,c &d) : Showing Survival and biomass of clam cultured in different substrata

It is interesting to note that the survival rate in the effluent used pond was not affected by the rearing density However, in the case of influent used ponds the survival rate of clam was significantly higher A comparative account of clam survival rate and total biomass related

to above treatment are given in table 2 and fig 4:a-d

Table 2 Survival and biomass of clam cultured in different densities

Density (Ind./

m2) Water system

Effluent Survival (%) 75.00 ±2.64 63.67±5.51 75.67±4.51

Biomas (kg/m2) 0.75±0.07 0.79±0.02 1.25±0.14 Influent Survival (%) 65.33±3.40 49.33±3.05 50.00±1.73

Biomas (kg/m2) 0.69±0.04 0.64±0.02 0.81±0.05

Fig 4: (a,b,c &d) showing survival and biomass of clam cultured in different densities

It was clear from the trials that effluent used pond systems produced higher survival rate and biomass (P<0.05) A comprson of the results obtained from influent and effluent system is presented in fig 5(a-f) Based on previous studies the total nitrogen level was maintained 1.5 ppm ± 0.5 ppm using normal seas water to prevent any toxic ( unionised ammonia level) in the pond This allowed more algal production 10 to 15% in effluent pond Therefore comparatively better environmental conditions plus more food resulted in higher survival rate and total biomass

Fig.5 (a-f) showing the comparison of survival rates and biomass of clam cultured in effluent and influent system

The environmental conditions of influent and effluent systems in particular, salinity, temperature and turbidity did not way significantly During experimental period of time, the salinity and turbidity were widely fluctuated The salinity fluctuated from 9%o (min) and 20%o (max) and the turbidity varied between 27 cm (min) & 57 cm (max) A detailed environmental data analysis along with chlorophyll levels will be reported in the next report

Biomass of clam cultured at 90 ind./m 2

in different culture system

b

Biomass of clam cultured at 120 ind./m 2

in different culture system

b

in different culture system

Fig.5:f

Average and specific growth performance of clam in the different treatments

This analysis has been done to understand average and specific growth performance under different treatments It may be noted that, in the case of the density of animal stocked and the density finally harvested drastically changed due to mortality In clam culture it is difficult to determine actual mortality until final harvest Therefore replacing died clams were impossible As explained in the comparative section, the survival rate in the effluent was higher than influent system Therefore, more number of clams were present compared to same density in the influent On an average 15% fewer animals survived in influent system This was certainly reflected in the growth performance of the clam In general influent system recorded marginally higher growth rate compared to effluent However, effluent system yielded more total biomass compared to influent system (P<0.05) In general high growth rate was recorded at lower stocking density The maximum growth rate was obtained

at a stocking density of 90 ind/m2.(table 3 and fig 6)

Table 3 Growth of clam cultured at different stocking densities in effluent and influent system:

indiv./m2

Figure 2 SGRW of clam cultured in effluent

at different stocking density

150 ind/m2 was still not be the upper barrier for growth performance among the three different densities and it seem more beneficial for farmers to stock at such high density as they can get higher production with comparative same price of land lease and other operation cost except the cost of seed stock That means a properly managed effluent pond could be used for high density clam production However, there is further work needed

 to determine the upper limit in terms of higher stocking density

 to determine the suitable nutrient load ( total nitrogen) in the effluent pond for optimising the production also require further studies

Present investigation relied on nutrient levels on aquaculture on the information from the studies conducted in freshwater polyculture ( ACIAR project) and integrated wastewater treatment and aquaculture production information

Table 5 Growth of clam cultured at different substrata in effluent and influent water system:

to obtain marketable size at desired time Size is an important factor which determines the price Since there is significantly higher mortality rate recorded in influent treatment, compared to effluent ponds, the relatively low number of animals impacted the substrate factor in the influent treatment The final weight of clam cultured in the influent was significant higher than that of cultured in the effluent when stocked at 90 & 120 ind./m2 (P<0.05, fig.7 a-f) However, at high stocking density of 150inds/m2, there were no significant difference between the two treatments (P>0.05)

Fig.7 (a-f) showing average and specific growth rate in different substrata

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

indiv./m2Figure 5 Weight of clam cultured in influent at different density

0.00 0.25 0.50 0.75 1.00 1.25

indiv./m2

b

Figure 6 SGRW of clam cultured in influent

at different stocking density

Fig.7 d

Fig.7 c

Fig.8: a-f showing comparison of final weight of clam cultured in effluent and influent system in different substrate and density

5.1.1.2 Experiment on polyculture of clam and shrimp in brackishwater ponds

The key objective of this trial was to develop clam husbandry technology for poly culture with prawn Since a number of other experiments concentrated on optimum size and suitable substrate, in this experiment the focus was on optimum stocking density without altering current prawn stocking procedure

Materials and method

In this experiment, clam was integrated with shrimp in brackishwater at different stocking

Figure 9 Weight of clam cultured

7.5 10.0 12.5

15.0

a

b

Figure 10 Weight of clam cultured

8 9 10 11 12 13

Figure 11 Weight of clam cultured

Fig.8 a

Fig.8 b

be monitored daily The nutrient such as Total N, Ammonia NH3, Nitrate NO3, Total Phosphorous and H2S will be monitored weekly Biological parameters including Phytoplankton (chlorophyll a) /L, Zooplankton /L, Zoobenthos no/m2 will be monitored weekly Clam were randomly sampled (30 inds for each pond) every 15 days for growth evaluation Experiment terminated after 105 days rearing All data of the treatments were tested for significant differences (P<0.05) using One-way ANOVA followed by Turkey test for multiple comparisons of means The data are expressed as Mean ± SD and statistical analysed was performed using Graphpad Prism version 4.0 and Microsoft Office EXCEL

Result and discussions

Clam growth rate including specific growth rate is presented in table 7 and fig.9 a &b It was clear from the table that clam growth was significantly higher in the 60ind/m2 treatment compared to 90ind/m2 and 120ind/m2 (P<0.05) However, the growth rates in 90ind/m2 and 120ind/m2 were not significantly different Food and space availability may be the main reason could be attributed to significantly higher growth rate in low stocking density

Table 7 Growth of clam cultured in shrimp culture ponds in brackishwater (Mean ± SD)

Density (ind./m2)

Figure 15 Weight of clam from polyculture

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

Density (ind./m2)