Effects of long-term chlorpyrifos exposure on mortality and reproductive tissues of Banded Gourami (Trichogaster fasciata).

This study assessed the long-term toxicity of chlorpyrifos on survival and reproduction of Banded Gourami by using mortality, gonado-somatic index (GSI) and histopathological observations as endpoints. Adult fish were exposed to five different concentrations of chlorpyrifos (0, 15, 50, 150, 500 µg/L) in 15 PVC tanks for 15, 30, 45, 60 and 75 days. Results showed that all male and female fish died after 15 days of 500 µg/L chlorpyrifos exposure. No consistent significant effect was observed for both male and female GSI. Furthermore, results showed dose- and time-dependent histopathological alterations for both ovary and testes. The 60-d No Observed Effect Concentration (NOEC) for most histopathological alterations of Banded Gourami ovary and testes was 50 µg/L, while 60-d NOEC for mortality of both male and female fish was < 15 µg/L. The results show that the long-term exposure to chlorpyrifos not only affect the reproductive tissues of Banded Gourami at exposure concentrations but also cause their mortality. Future studies should evaluate effects at lower concentrations.

Environmental monitoring and risk assessment of organophosphate pesticides in aquatic ecosystems of north-west Bangladesh.

The use of organophosphate pesticides (OPPs) to protect a variety of crops has increased in Bangladesh. OPPs may contaminate surrounding aquatic environments through several routes including spray drift, surface runoff and groundwater leaching. Since it is unknown how much OPP end ups in aquatic environment in Bangladesh, the objectives of the present study were to quantify the residues of ten most commonly used OPPs in water and sediment of water bodies of north-west Bangladesh and to assess their ecological risks for aquatic organisms. The risks of the pesticides in surface water and sediment were assessed using a first-tier risk quotient (RQ) approach. The higher-tier PERPEST model was used to refine the ecological risks of pesticides when RQ indicated a potential risk. Results showed the most frequently detected pesticides that appeared in high concentrations were chlorpyrifos, diazinon and quinalphos in surface water and sediment. The highest concentration of OPPs measured in water was 9.1 µg chlorpyrifos/L (median of 1.95 µg/L), while this was 51 µg diazinon/kg dw (median of 11 µg/kg dw) for sediment. Furthermore, results showed high acute and/or chronic RQs (RQ > 1) in surface water and sediment for chlorpyrifos, diazinon, quinalphos, malathion and fenitrothion. The higher-tier PERPEST model confirmed risks of chlorpyrifos, diazinon, quinalphos and fenitrothion for aquatic insects, micro- and macro-crustaceans which were previously derived by RQ-based risk assessment for aquatic organisms. Furthermore, the results of the PERPEST model also indicated possible indirect effects of these pesticides on algae and macrophytes, community metabolism, rotifers and other macro-invertebrates.

Effects of imidacloprid on the ecology of sub-tropical freshwater microcosms.

The neonicotinoid insecticide imidacloprid is used in Bangladesh for a variety of crop protection purposes. Imidacloprid may contaminate aquatic ecosystems via spray drift, surface runoff and ground water leaching. The present study aimed at assessing the fate and effects of imidacloprid on structural (phytoplankton, zooplankton, macroinvertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater, sub-tropical ecosystems in Bangladesh. Imidacloprid was applied weekly to 16 freshwater microcosms (PVC tanks containing 400 L de-chlorinated tap water) at nominal concentrations of 0, 30, 300, 3000 ng/L over a period of 4 weeks. Results indicated that imidacloprid concentrations from the microcosm water column declined rapidly. Univariate and multivariate analysis showed significant effects of imidacloprid on the zooplankton and macroinvertebrate community, some individual phytoplankton taxa, and water quality variables (i.e. DO, alkalinity, ammonia and nitrate), with Cloeon sp., Diaptomus sp. and Keratella sp. being the most affected species, i.e. showing lower abundance values in all treatments compared to the control. The observed high sensitivity of Cloeon sp. and Diaptomus sp. was confirmed by the results of single species tests. No significant effects were observed on the species composition of the phytoplankton, periphyton biomass and organic matter decomposition for any of the sampling days. Our study indicates that (sub-)tropical aquatic ecosystems can be much more sensitive to imidacloprid compared to temperate ones.

Acute toxicity of chlorpyrifos to embryo and larvae of banded gourami Trichogaster fasciata.

This study elucidated the acute toxicity of chlorpyrifos on the early life stages of banded gourami (Trichogaster fasciata). To determine the acute effects of chlorpyrifos on their survival and development, we exposedthe embryos and two-day-old larvae to six concentrations (0, 0.01, 0.10, 1.0, 10 and 100 µg L-1) of chlorpyrifos in plastic bowls. Log-logistic regression was used to calculate LC10 and LC50 values. Results showed that embryo mortality significantly increased with increasing chlorpyrifos concentrations. The 24-h LC10 and LC50 values (with 95% confidence limits) of chlorpyrifos for embryos were 0.89 (0.50-1.58) and 11.8 (9.12-15.4) µg L-1, respectively. Hatching success decreased and mortality of larvae significantly increased with increasing concentrations of chlorpyrifos. The 24-h LC10 and LC50 values (with 95% confidence limits) of chlorpyrifos for larvae were 0.53 (0.27-1.06) and 21.7 (15.9-29.4) µg L-1, respectively; the 48-h LC10 and LC50 for larvae were 0.04 (0.02-0.09) and 5.47 (3.77-7.94) µg L-1, respectively. The results of this study suggest that 1 µg L-1 of chlorpyrifos in the aquatic environment may adversely affect the development and the reproduction of banded gourami. Our study also suggests that banded gourami fish can serve as an ideal model species for evaluating developmental toxicity of environmental contaminants.

Environmental impact of non-certified versus certified (ASC) intensive Pangasius aquaculture in Vietnam, a comparison based on a statistically supported LCA.

Pangasius production in Vietnam is widely known as a success story in aquaculture, the fastest growing global food system because of its tremendous expansion by volume, value and the number of international markets to which Pangasius has been exported in recent years. While certification schemes are becoming significant features of international fish trade and marketing, an increasing number of Pangasius producers have followed at least one of the certification schemes recognised by international markets to incorporate environmental and social sustainability practices in aquaculture, typically the Pangasius Aquaculture Dialogue (PAD) scheme certified by the Aquaculture Stewardship Council (ASC). An assessment of the environmental benefit of applying certification schemes on Pangasius production, however, is still needed. This article compared the environmental impact of ASC-certified versus non-ASC certified intensive Pangasius aquaculture, using a statistically supported LCA. We focused on both resource-related (water, land and total resources) and emissions-related (global warming, acidification, freshwater and marine eutrophication) categories. The ASC certification scheme was shown to be a good approach for determining adequate environmental sustainability, especially concerning emissions-related categories, in Pangasius production. However, the non-ASC certified farms, due to the large spread, the impact (e.g., water resources and freshwater eutrophication) was possibly lower for a certain farm. However, this result was not generally prominent. Further improvements in intensive Pangasius production to inspire certification schemes are proposed, e.g., making the implementation of certification schemes more affordable, well-oriented and facilitated; reducing consumed feed amounts and of the incorporated share in fishmeal, especially domestic fishmeal, etc. However, their implementation should be vetted with key stakeholders to assess their feasibility.

Exploring the climate change concerns of striped catfish producers in the Mekong Delta, Vietnam.

This study investigated the perceptions on and adaptations to climate change impacts of 235 pangasius farmers in the Mekong Delta, Vietnam. Data were collected using semi-structured household surveys in six provinces, from three regions along the Mekong river branches. A Chi-Square test was used to determine the association between variables, and a logit regression model was employed to identify factors correlated with farmer's perception and adaptation. Less than half of respondents were concerned about climate change and sought suitable adaptation measures to alleviate its impacts. Improving information on climate change and introducing early warning systems could improve the adaptive capacity of pangasius farmers, in particularly for those farmers, who were not concerned yet. Farmers relied strongly on technical support from government agencies, but farmers in the coastal provinces did not express the need for training by these institutions. This contrasting result requires further assessment of the effectiveness of adaptation measures such as breeding salinity tolerant pangasius.

Simulated impacts of climate change on current farming locations of striped catfish (Pangasianodon hypophthalmus; Sauvage) in the Mekong Delta, Vietnam.

In Vietnam, culturing striped catfish makes an important contribution to the Mekong Delta's economy. Water level rise during rainy season and salt intrusion during dry season affect the water exchange and quality for this culture. Sea level rise as a consequence of climate change will worsen these influences. In this study, water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e., +30, +50, and +75 cm) were simulated. The results showed that at SLR +50, the 3-m-flood level would spread downstream and threaten farms located in AnGiang, DongThap and CanTho provinces. Rising salinity levels for SLR +75 would reduce the window appropriate for the culture in SocTrang and BenTre provinces, and in TienGiang's coastal districts. Next to increasing dikes to reduce the impacts, the most tenable and least disruptive option to the farming community would be to shift to a salinity tolerant strain of catfish.

Effect of hygiene and medication on preweaning survival and growth of Djallonké sheep in Atacora, Benin.

Low sheep productivity in North Benin hampers economic development, and improvement can contribute to reduction of rural poverty and food insecurity. To reduce one of the constraints to the productivity of Djallonké sheep, high mortality during suckling in full rainy and start dry season, we tested hygienic measures and medication in improved housing. The effect of the two treatments and their combination on lamb performance and the internal rate of return (IRR) were compared to a control. For each treatment, survival and growth were observed in 20 lambs, living in 38 herds. Good housing and hygiene (daily cleaning and fortnightly disinfection of stable and water and feed troughs) reduced mortality and increased growth of suckling lambs until 3 months. Good housing plus medication (unique injection of vitamins and amino acids and with ivermectine for deworming, weekly tick treatment by spraying, and in case of diarrhea, antibiotic treatment) reduced mortality, but growth was not higher than the control. Accounting labor opportunity, the IRR was about equal for both, but capital investment was lower for the hygiene treatment which is thus more accessible to poor farmers. The combination of both treatments increased growth and benefits compared with the hygiene treatment, but decreased the IRR.

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.

Challenges of a transition to a sustainably managed shrimp culture agro-ecosystem in the Mahakam delta, East Kalimantan, Indonesia.

Around 1990, when in other countries mangrove protection took off, massive conversion of mangrove forest into shrimp ponds started in the Mahakam delta. To identify constraints to and options for sustainable management we analysed institutions and constraints with stakeholders. In 3 sites we used participatory tools and a complementary survey to assess the livelihood framework. Since 1970, ponds for shrimp farming gradually replaced 75% of mangrove forested area. After 2004, recovery of mangrove took off, as, mainly due to low shrimp yields, ponds were abandoned. In 2008, 54% of the delta was dedicated to ponds for shrimp production. Around 80% of livelihood activities of pond-farmers, pond caretakers, and fishermen was related to mangroves. The involvement of men and women in these activities varied between sites and types. Poor households depended more on mangroves. Most activities resulted in seasonal income peaks; only a few activities resulted in a full daily livelihood. Ponds, on the other hand, provide 50% of households' livelihood, but this remains vulnerable in the context of the risky shrimp production. Skewed land holding, unequal sharing of benefits, competing claims and vested interests of stakeholders pose a great challenge to a transition to a more sustainable use of the mangrove area. In particular, ponds located on peat soils are non-sustainable and would require full restoration into mangrove; ponds on other soils could best be transformed into a mixed mangrove-pond system using a 'green-water' technology.