Importance of various marine coastal habitats during the life cycle of Spratelloides delicatulus in Con Dao,the oldest MPA in Vietnam

• 1. Marine protected areas (MPAs) are set up to conserve biodiversity, but their design is not always based on strictly scientific considerations. Ideally, an MPA should protect all key habitats necessary for a marine species to complete its life cycle. The identification of these key habitats is complex, especially during the early life of marine fishes.
• 2. A widely distributed tropical and important low trophic‐level fish species, Spratelloides delicatulus (Clupeidae), was used to evaluate the significance of various coastal habitats for its larvae and juveniles in the Con Dao Archipelago MPA in Vietnam. Early stages (larvae and juveniles) were sampled monthly over one year (June 2016 to May 2017) using light traps in three main habitats (seagrass beds, coral reefs and harbour). The species was identified using morphometry and DNA barcoding. Age and growth variables were estimated using otolith daily growth increments.
• 3. A total of 3,581 fish were caught. The species was not found in captures between January and February, directly linked to the decrease in seawater temperature and was most abundant from April to June. For a subsample of 248 fish (7–38 mm standard length), ages ranged from 7 to 108 days.
• 4. Captures and back‐calculated birthdates using otolith daily increments showed that S. delicatulus spawns during the period of high seawater temperature, from March to October. The species colonizes all three habitats during the early stages (0–26 days old), with growth rate lowest on the seagrass beds. Nevertheless, the species occupies seagrass beds exclusively during the older stages.
• 5. The conservation of seagrass beds in the Con Dao archipelago is essential for protection of juvenile stages of this species but this habitat is presently not included in the MPA patches. Establishment of a continuum of protected areas linking habitats, rather than the existing patches is needed to conserve the complete life cycle of this species in the Con Dao MPA.

     

Hard choices: Making trade-offs between biodiversity conservation and human well-being

Win–win solutions that both conserve biodiversity and promote human well-being are difficult to realize. Trade-offs and the hard choices they entail are the norm. Since 2008, the Advancing Conservation in a Social Context (ACSC) research initiative has been investigating the complex trade-offs that exist between human well-being and biodiversity conservation goals, and between conservation and other economic, political and social agendas across multiple scales. Resolving trade-offs is difficult because social problems – of which conservation is one – can be perceived and understood in a variety of disparate ways, influenced (in part at least) by how people are raised and educated, their life experiences, and the options they have faced. Pre-existing assumptions about the “right” approach to conservation often obscure important differences in both power and understanding, and can limit the success of policy and programmatic interventions. The new conservation debate challenges conservationists to be explicit about losses, costs, and hard choices so they can be openly discussed and honestly negotiated. Not to do so can lead to unrealized expectations, and ultimately to unresolved conflict. This paper explores the background and limitations of win–win approaches to conservation and human well-being, discusses the prospect of approaching conservation challenges in terms of trade-offs and hard choices, and presents a set of guiding principles that can serve to orient strategic analysis and communication regarding trade-offs.     

氮素营养对稻米理化特性及淀粉谱特性的影响

利用 7个粳稻品种 ,研究了氮素营养对稻米理化特性及淀粉谱特性的影响。结果表明 ,随着氮素营养的增加 ,胶稠度逐渐变短 ,蛋白质含量和碱消值及糊化开始温度逐渐提高 ,但直链淀粉含量和最高粘度、最低粘度、最终粘度、下降粘度值、回冷粘滞性恢复值等特性逐渐下降或变小 ,在全生育期施氮量相同时 ,与生育前期追施氮肥相比 ,抽穗期追施氮肥 ,其胶稠度变短 ,蛋白质含量有增加 ,直链淀粉含量略有下降 ,碱消值变化很小 ,在淀粉谱特性中除糊化开始温度没有变化外 ,其余各项指标均表现略高 ,但差异很小 ,在理化特性及淀粉谱特性中受氮素影响较大的是蛋白质含量、胶稠度、下降粘度值及最高粘度     

Effects of size and nitrite exposure on respiration,oxygen partitioning,and growth of obligate air-breathing fish Channa striata

The effects of fish size and nitrite level on metabolic rate and growth were investigated in the obligate air-breathing snakehead Channa striata, which is an important aquaculture species in Vietnam. Channa striata displayed respiratory size dependence, whereby the standard metabolic rate (SMR) and routine metabolic rate (RMR) decreased progressively in an exponential manner as fish size increased from 50 to 200 g. A mildly elevated nitrite level of 5% of the LC₅₀ 96 h (12 mg NO₂^?/L or safe concentration) induced significant increases in Channa striata SMR and RMR, which were almost double that of the control at the same size. At mild elevation, nitrite caused no significant effect on fish growth and survival during 3 months of rearing. However, both growth and survival rates of fish reared at severely elevated nitrite levels were significantly lower than those of the control; in particular, survival rates were under 50%. While changes in size reduced SMR and RMR, the percentage of air oxygen partitioning remained unchanged. Channa striata upregulation of SMR and RMR and air-breathing regulation were not significantly proven in this study. In summary, maintaining water environments at levels lower than 12 mg NO₂^?/L with ample oxygenation will not affect the growth and survival rate of snakeheads.

     

Maturation and spawning performance of pond-reared Penaeus merguiensis in different combinations of temperature, light intensity and photoperiod

The combined effects of temperature (23 and 27 °C), light intensity (1100 and 2 lux or ≈ 21.5 and 0.04 μEinst m^?2 s respectively) and photoperiod (10 h light/14 h dark and 14 h light/10 h dark) on ovarian maturation and spawning performance of ablated pond‐reared Penaeus merguiensis were investigated in a 51‐day experiment. The results showed that temperature was the most influential factor, followed by light intensity, whereas the effect of photoperiod was minor. As the maturation process progressed, the effects of temperature and light intensity became stronger while that of photoperiod became less significant. Temperature significantly affected all the reproductive parameters assessed. Prawns in the 27 °C treatments outperformed those in the 23 °C treatments (P < 0.05). The effect of light intensity was found to have a significant effect (P < 0.05) only on the proportion of spawners (prawns that spawned) and spawning rate. More prawns spawned at a higher rate under dim light (2 lux) than under strong light (1100 lux). Photoperiod affected only the proportion of prawns reaching stage III of ovarian development (P < 0.05). There were interactions between temperature and light intensity affecting the proportion of prawns reaching stage III and, although not significantly, the proportion of spawners (P = 0.177), fecundity (P = 0.134) and survival (P = 0.061). Overall, it is recommended that a combination of 27 °C, 2 lux and 10 h light/14 h dark is suitable for the maturation of pond‐reared P. merguiensis. There were indications that temperature can be used to control the rate of ovarian maturation. Also, it is possible to increase light intensity up to 1100 lux in P. merguiensis hatcheries if prawns are ablated.     

竹集成材高频热压胶合工艺及性能研究

采用酚醛树脂胶黏剂,以竹条含水率、涂胶量为试验因子进行竹集成材的高频热压胶合试验,并对其物理力学性能进行检验.结果表明,竹集成材高频热压胶合技术是可行的.在本试验范围内,竹集成材的密度和胶合性能随涂胶量的增加而提高.通过分析试验数据,得出较优的高频热压胶合工艺条件为:涂胶量300 g/m2,竹条含水率12％,高频热压时间10 min.     

Cold tolerance of the banana prawn Penaeus merguiensis de Man and its growth at different temperatures

Critical thermal minima (CTMin) were determined for subadults of Penaeus merguiensis acclimated at 15, 18, 21 and 24 °C for 3 weeks. The effect of cooling rate on CTMin was also investigated. The CTMin of prawns from these respective acclimation groups were 5.3, 6.0, 7.4, 9.0 and 4.7, 5.4, 6.0, 7.3 °C at the cooling rate of 1 °C h^?1 and 3 °C h^?1 respectively. Both acclimation temperature and cooling rate had a significant effect (P < 0.01) on the CTMin. Observation during the acclimation period showed that the growth rate of prawns acclimated at 24 °C was much higher than those acclimated at 21, 18 and 15 °C. The results indicate that P. merguiensis can overwinter in aquaculture ponds in south‐east Queensland, Australia, or other subtropical areas and attain good growth if simple overwintering facilities are available.     

Antimicrobial resistance in Escherichia coli isolated from brown rats and house shrews in markets,Bogor, Indonesia

The prevalence of antimicrobial resistance (AMR) in small mammals dwelling in the city was used as an indicator of AMR bacteria in the environment. We captured 87 small mammals (79 brown rats and 8 house shrews) in four markets, Bogor, Indonesia in October 2019, and we obtained 20 AMR Escherichia coli (E. coil) from 18 brown rats and two house shrews. Of these, eight isolates were determined to be multi-drug resistant (MDR) E. coli, suggesting the potential contamination of AMR E. coli in the markets in Bogor, Indonesia, and that mammals, including humans, are at risk of infection with AMR E. coli from environment.     

Application of a real-time PCR assay for the detection of Ascaris suum DNA in the liver of experimentally infected chickens

This study aimed to evaluate the sampling method for the detection of Ascaris suum larval DNA in chicken livers using real-time PCR. Chickens were inoculated with A. suum eggs of a single dose (Group A) or repeatedly low doses (Group B). White spots (WSs) were continuously observed on liver from day 3 after the last infection in Group B and day 14 in Group A. In Group A, larval DNA was detected in WS lesions (78.6%) at a significantly higher rate than in the remaining tissue samples (31.3%). In conclusion, applying WS lesions to the assay improved the detection rate of A. suum DNA in chicken livers, especially in the case of a single infection.