Life cycle assessment of intensive striped catfish farming in the Mekong Delta for screening hotspots as input to environmental policy and research agenda

Purpose Intensive striped catfish production in the Mekong Delta has, in recent years, raised environmental concerns. We conducted a stakeholder-based screening life cycle assessment (LCA) of the intensive farming system to determine the critical environmental impact and their causative processes in producing striped catfish. Additional to the LCA, we assessed water use and flooding hazards in the Mekong Delta. Materials and methods The goal and scope of the LCA were defined in a stakeholder workshop. It was decided there to include all processes up to the exit-gate of the fish farm in the inventory and to focus life cycle impact assessment on global warming, acidification, eutrophication, human toxicity, and marine (MAET) and freshwater aquatic ecotoxicity (FWET). A survey was used to collect primary inventory data from 28 farms on fish grow-out, and from seven feed mills. Hatching and nursing of striped catfish fingerlings were not included in the assessment due to limited data availability and low estimated impact. Average feed composition for all farms had to be applied due to limitation of budget and data availability. Results and discussion Feed ingredient production, transport and milling dominated most of the impact categories in the LCA except for eutrophication and FWET. Most feed ingredients were produced outside Vietnam, and the impact of transport was important. Because of the screening character of this LCA, generic instead of specific inventory data were used for modelling feed ingredient production. However, the use of generic data is unlikely to have affected the main findings, given the dominance of feed production in all impact categories. Of the feed ingredients, rice bran contributed the most to global warming and acidification, while wheat bran contributed the most to eutrophication. The dominance of both was mainly due to the amounts used. Fishmeal production, transport and energy contributed the most to MAET. The biggest impacts of grow-out farming in Vietnam are on eutrophication and FWET. Water nutrient discharge from grow-out farming was high but negligible compared with the natural nutrient content of the Mekong River. The discharge from all grow-out farms together hardly modified river water quality compared with that before sector expansion. Conclusions Feed production, i.e. ingredient production and transport and milling, remains the main contributor to most impact categories. It contributes indirectly to eutrophication and FWET through the pond effluents. The environmental impact of Pangasius grow-out farming can be reduced by effectively managing sludge and by using feeds with lower feed conversion ratio and lower content of fishery products in the feed. To consider farm variability, a next LCA of aquaculture should enlist closer collaboration from several feed-milling companies and sample farms using their feeds. Future LCAs should also preferably collect specific instead of generic inventory data for feed ingredient production, and include biodiversity and primary production as impact categories

"Farmer Field-school" en LEISA: ook goed voor aquacultuur

De Indonesische boeren die melkvis en garnalen produceren in hun vijvers langs de kust zijn zelden goed getraind in de aquacultuur. De overheidsdiensten proberen de productie met gratis pootgoed en summiere instructies op te krikken. Maar goede training en aangepaste teeltmethoden maken groot verschil, ook in Indonesië. Bodemdaling blijft een bedreiging voor de vijvers van de boeren die weer hoop krijgen na een degelijke training. Het Ecoshape project Bouwen met Natuur stimuleert ze ook om de mangrove in het landschap terug te brengen

Monitoring quantity and quality of pangasius pond effluent : report of a monitoring program and recommendations for certification

The quantity and quality of pangasius pond effluent was monitored by means of monthly sampling during a study conducted on four striped catfish farms located in the Mekong Delta, Vietnam. The study was undertaken to test the practical implications of the standards and guidelines with regard to catfish pond effluent that are at present developed by various certification programs for striped catfish production in Vietnam. The results showed a great variability twelve pangasius pond within the samples that were taken during one period of partial pond draining and refilling. The consequences of such variability with regard to the certification standards and guidelines are discussed and recommendations are given

Toward optimal control of flat plate photobioreactors: the greenhouse analogy?

Abstract: The cultivation of algae in photo-bioreactors shows similarities to crop cultivation in greenhouses, especially when the reactors are driven by sun light. Advanced methodologies for dynamic optimization and optimal control for greenhouses are known from earlier research. The aim here is to extend these methodologies to microalgae cultivated in a flat plate photo-bioreactor. A one-state space model for the algal biomass in the reactor is presented. The growth rate vs. light curve is parameterized on the basis of experimental evidence. Spatial distribution of light and growth rate between the plates is also considered. The control variable is the dilution rate. Dynamic optimal control trajectories are presented for various choices of goal function and external solar irradiation trajectories over a horizon of 3 days. It was found that the algae present in the reactor at final time represent a value for the future. Numerical and theoretical results suggest that the control is bang-(singular-)bang, with a strong dependence on the weather. The optimal biomass also depends on the available light, and achieving it to reach a new optimal steady cycle after a prolonged change in weather may take several days. A preliminary theoretical analysis suggests a control law that maximizes the effective growth rate. The analysis shows that like in the greenhouse case, the co-state of the algal biomass plays a pivot role in developing on-line controllers

Perspectieven voor vijverteelt

Europa, waar de belangrijke kweeksoorten zalm, zeebaars, zeebrasem en tonijn vooral in kooien op zee gekweekt worden, is een buitenbeentje in de mondiale aquacultuur scene. Op wereldschaal wordt het leeuwendeel van vis en schaaldieren gekweekt in vijvers. Van de op gewichtsbasis 20 belangrijkste gekweekte vissoorten worden alleen zalm en regenboogforel niet hoofdzakelijk in vijvers gekweekt. Van de mondiale productie van gekweekte garnalen wordt meer dan 95% in vijvers gekweekt. Hoe duurzaam is de teelt in vijvers, en biedt vijverteelt de oplossing om te voldoen aan de groeiende vraag naar vis en schaaldieren in de wereld

Scenarios for Resilient Shrimp Aquaculture in Tropical Coastal Areas

We contend there are currently two competing scenarios for the sustainable development of shrimp aquaculture in coastal areas of Southeast Asia. First, a landscape approach, where farming techniques for small-scale producers are integrated into intertidal areas in a way that the ecological functions of mangroves are maintained and shrimp farming diseases are controlled. Second, a closed system approach, where problems of disease and effluent are eliminated in closed recirculation ponds behind the intertidal zone controlled by industrial-scale producers. We use these scenarios as two ends of a spectrum of possible interactions at a range of scales between the ecological, social, and political dynamics that underlie the threat to the resilience of mangrove forested coastal ecosystems. We discuss how the analytical concepts of resilience, uncertainty, risk, and the organizing heuristic of scale can assist us to understand decision making over shrimp production, and in doing so, explore their use in the empirical research areas of coastal ecology, shrimp health management and epidemiology, livelihoods, and governance in response to the two scenarios. Our conclusion focuses on a series of questions that map out a new interdisciplinary research agenda for sustainable shrimp aquaculture in coastal area

Aquaculture Stewardship Council (ASC) ontwikkeltraject meerval

De Nederlandse viskweeksector bestaat uit bedrijven die hun vis kweken in Recirculatiesystemen (RAS), met name de meervalsector (lees Afrikaanse meerval en Claresse) wordt gestimuleerd om in te spelen op de trend van certificering voor duurzaamheid om zich hiermee aanvullend te onderscheiden van andere aquacultuurproducten). Nederlandse kwekers kunnen hun bedrijven (en hiermee het productieproces) al laten certificeren voor Milieukeur, maar dit label is beperkt beschikbaar in Nederlandse supermarkten en geeft in Nederland onvoldoende en andere Europese landen geen herkenning voor consumenten. De Aquaculture Stewardship Council (ASC) biedt die mogelijkheid wel. Een inventarisatie naar de mogelijkheden om een standaardisatietraject voor Afrikaanse meerval / Claresse te realiseren is uitgevoerd. Hierbij zijn de mogelijke ambitieniveaus, benodigde procedures en de bijbehorende kosten in kaart gebracht. Aanvullend is een studie uitgevoerd voor tarbot. Een certificeringstraject in het kader van ASC is voor de Nederlandse meerval (en tarbot) sector haalbaar, de kosten en baten zullen echter afgewogen moeten worden. Er dienen hierbij keuzes gemaakt te worden in de richting van een dergelijk proces. Er kan gekozen worden voor een proces in de richting van standaardisering voor Afrikaanse meerval/Claresse. Hiermee is het traject direct gebonden aan een bredere aanpak naar Afrikaanse landen (met name Nigeria), aangezien hier een groot deel van de Afrikaanse meerval productie plaatsvindt. Daarnaast zijn er mogelijkheden om een standaardisatietraject in te gaan voor een hogere meervalgroep de Clariidae, waaronder de in Nederland gekweekte soorten vallen. De processen worden hiermee verbreed naar oa Aziatische landen. De kosten en procesduur zullen hiermee toenemen, de reikwijdte zal groter zijn, de overige effecten worden in het rapport weergegeven. Alle trajecten die voor het behalen van een ASC certificering (en voorafgaand de standaarden) gevolgd worden dienen aan de eisen van ISEAL (International Social and Environmental Accreditation and Labelling Alliance) te voldoen. Dit vergt een adequate procesbeschrijving en bewaking, waarin alle stakeholders de mogelijkheid dienen te krijgen om input en invulling aan het proces te geven. De kosten voor een procedure rond Afrikaanse meerval bedragen ruim 440 k€ (schatting). Een uitgebreidere variant voor alle meervalsoorten (exclusief pangasius) zal 675 k€ bedragen. Voor de Nederlandse meervalsector zijn al verschillende duurzaamheidsinventarisatietrajecten doorlopen. In veel gevallen zijn de data om te komen tot een standaard aanwezig. Deze kunnen in de processen worden ingebracht. Voor ASC zullen er nog aanvullende eisen gesteld worden, welke in het ontwikkelproces nader onderbouwd dienen te worden. Het behoeft aanbeveling om, naast een traject voor vissoorten, de mogelijkheden te beoordelen voor een ontwikkelingstraject voor ASC standaarden op het niveau van kweeksystemen

Effect of ingredient particle sizes and dietary viscosity on digestion and faecal waste of striped catfish (Pangasianodon hypophthalmus)

The ingredients' particle size and dietary viscosity may alter digestion, performance and faecal waste management of fish. This study aimed to assess the effect of grinding screen sizes of feed ingredients and dietary viscosity on digestibility, faecal waste and performance of striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878). The experiment had a 2 × 3 factorial-design: two feed mesh particle sizes, by grinding ingredient mixtures at two screen sizes (0.8 versus 1.0 mm); and three dietary viscosity levels, created by exchanging carboxymethylcellulose by guar gum (GG) (0, 3 and 6 g of GG/kg of diet). Six diets were assigned to 18 tanks, each connected to three faecal settling tanks. All aquaria were stocked with 20 fish (82 g per fish). After 52 experimental days, dietary viscosity negatively affected both feed digestibility and performance of striped catfish; as a result, the amount of organic matter in the culture system through faeces had increased significantly. The coarse diets significantly increased the digestibility of dry matter and carbohydrate but worsened feed conversion ratio. Increasing dietary viscosity tended to increase the viscosity and moisture content of the faeces, but significantly accelerated the faecal disintegration through the reduction of both faecal recovery and the amount of recovered faeces.</p

FeedCalculator, een app om rantsoenen voor vis te berekenen

De Nederlandse sociale onderneming Single Spark heeft een smartphone app ontwikkeld waarmee kleine boeren en bedrijven zelf rantsoenen voor hun dieren kunnen berekenen (zie foto’s onder). Dat geeft hen de mogelijkheid goedkopere grondstoffen, zoals hun eigen oogstresten, te gebruiken en toch een optimaal rantsoen te voeren. Nadat het wereldwijd voor kippen en varkens was uitgerold, is de app in 2018 getest voor meerval en tilapia in resp. Nigeria en Benin

Effect of Time (Within and Between Days), and Dairy Production Factors on the Impedance Value at 24 Acupuncture Points in Dairy Cows

This study evaluated the effect of hour and day of measurement, and of production factors on the impedance values (IVs) at 24 acupuncture points (APs). This is a first step in assessing whether electro-acupuncture can contribute to reduced antibiotic use in dairy farming. The APs studied were left (L) and right (R) points of the bladder (BL) and stomach (ST) meridians. The effect of time was measured in a 3x3 Latin square on six cows in one herd. The effect of production factors was analyzed using 108 cows from three herds for two months. The effect of time excludes BL 14R, 16R, 21R, 22R, 30R, 46-02R, 43-01L and 30L, and ST18 bilaterally for diagnostic use. The contribution of parity, age or lactation period to monthly models of BL21R, 18R and 15R, and ST18R exclude these for diagnostic use. Of the remaining APs, BL19R, BL20R and BL46-02L showed stable IVs and are recommended for reference measurements. APs BL14L, BL16L and BL17L are recommended for diagnostics, and BL 16R, 17R, 18R, 23R, 30R, 15L, 20L, 22L and 29L need further study. Factors contributing to the variation in the IV of several APs were: milk robot, number of inseminations, body condition score, days of the preceding lactation, kg milk and kg milk fat of current and preceding month and preceding year, and milk cell count and urea content