Marine capture fisheries in the Arctic: winners or losers under climate change and ocean acidification?          下载免费PDF全文

Vicky W Y Lam  William W L Cheung  U Rashid Sumaila 《Fish and Fisheries》2016,17(2):335-357

Climate change, ocean acidification (OA) and the subsequent changes in marine productivity may affect fisheries and eventually the whole economy in the Arctic. We analysed how changes in climate and ocean pH under scenarios of anthropogenic CO₂ emissions are likely to affect the economics of marine fisheries in the Arctic. We applied a Dynamic Bioclimate Envelope Model (DBEM) and outputs from four different Earth System Models (ESMs) to project future changes in the distribution and maximum catch potential of exploited marine fishes and invertebrates. We projected that total fisheries revenue in the Arctic region may increase by 39% (14–59%) by 2050 relative to 2000 under the Special Reports on Emission Scenario (SRES) A2. Simultaneously, total fishing costs, fishers’ incomes, household incomes and economy‐wide impacts in the Arctic are also projected to increase. Climate change with OA is expected to reduce the potential increases in catch and the economic indicators studied herein. Although the projections suggest that Arctic countries are likely to be ‘winners’ under climate change in comparison with tropical developing countries, the effects of OA will lower the expected future benefits in the Arctic. The predicted impacts are likely to be conservative as we consider only the direct effects of OA on fishes and calcifiers, of which there are only a few in the Arctic. Results of this study would be useful for designing effective adaptation strategies to climate change and measures to mitigate the potential negative impacts of OA in the Arctic.  相似文献   

ECONOMIC ANALYSIS OF NETCAGE VERSUS SEA-BAG PRODUCTION SYSTEMS FOR SALMON AQUACULTURE IN BRITISH COLUMBIA     

Yajie Liu  Ussif Rashid Sumaila 《Aquaculture Economics & Management (Blackwell Science)》2013,17(4):371-395

Conventional open netcage systems for salmon aquaculture are under scrutiny and criticism partially because they are believed to generate adverse environmental impacts on other resource users and the surrounding environment. One alternative to preventing or miniming these impacts is to use enclosed systems. Experience indicates that these enclosed systems are technically feasible and environmentally promising, but they are economically demanding because of high capital and operating costs. Therefore, an economic analysis of open netcage and sea-bag systems for salmon aquaculture was conducted to examine the profitability of salmon aquaculture operations between these two systems. The study shows that netcage systems are more financially profitable than sea-bag systems when environmental costs are either not or only partially considered. Sea-bag systems can be financially profitable only when they produce fish that achieve a price premium. Sensitivity analyses reveal that market price has the most important impact on the profitability of both systems; changes in discount rates, fish density, feed costs, and environmental costs also have major impacts on the profitability of netcage systems. Changes in the length of the growth cycle, survival rate, and feed conversion ratio have minor impacts on the profitability of sea-bag systems.  相似文献   

Determination of oil palm fresh fruit bunch ripeness—Based on flavonoids and anthocyanin content     

Mohd Hafiz Mohd HazirAbdul Rashid Mohamed Shariff  Mohd Din Amiruddin 《Industrial Crops and Products》2012,36(1):466-475

Non-destructive and real-time oil palm fresh fruit bunch (FFB) grading systems are of major exploratory concern for researchers in the oil palm industry. The objective is to reduce time, labour, costs, and most importantly, to increase the oil extraction rate, in order to achieve a good quality of palm oil at a more acceptable price. This research investigates the potential of flavonoids and anthocyanins as a predictor to classify the degree of oil palm FFB ripeness. This paper also discusses the relationship between these predictors and the ripeness categories period. One hundred and eighty oil palm FFB samples were collected from a private plantation in Malaysia, according to three maturity categories i.e., ripe, under-ripe, and over-ripe. Each sample was randomly scanned 10 times, both front and back using a hand-held Multiplex^®3 multi-parameter fluorescence sensor. The results show that flavonoid and anthocyanin content decreased from immature to over mature oil palm FFBs. Overall, the relationship using Pearson's correlation between flavonoids and anthocyanins was r² = 0.84 and the most outstanding relationship accuracy was at the over-ripe stage, at 90%. Statistical analysis using analysis of variance (ANOVA) and pair-wise testing proved that both predictors gave significance difference between under-ripe, ripe, and over-ripe maturity categories. This shows that both predictors can be good indicators to classify oil palm FFB. Classification analysis was performed by using both predictors together and separately through several methods. The highest overall classification accuracy was 87.7% using a Stochastic Gradient Boosting Trees model and with both predictors. The other classification methods used either independent or both predictors together and gave various results ranging from 50 to 85% accuracy. This research proves that flavonoids and anthocyanins can be used as predictors of oil palm maturity classification.  相似文献   

Water quality influences the presence of Streptococcus agalactiae in cage cultured red hybrid tilapia,Oreochromis niloticus × Oreochromis mossambicus          下载免费PDF全文

Mohammad Noor Azmai Amal  Mohd Zamri Saad  Abdullah Siti Zahrah  Abd Rashid Zulkafli 《Aquaculture Research》2015,46(2):313-323

Attempts were made to identify the association between water quality parameters and the presence of Streptococcus agalactiae in cage cultured red hybrid tilapia, Oreochromis niloticus × O. mossambicus. Fish from commercial floating net cage‐culture systems in a river and lake were randomly sampled over a 24‐month period. Swabs from the brains, eyes and kidneys were streaked directly onto blood agar to isolate S. agalactiae. Water temperature, dissolved oxygen, pH, clarity, ammonia, nitrite, sulfide, rate of water flow and depth of water at sampling sites were measured at the same time of fish sampling. The prevalence of fish that were cultured positive to S. agalactiae was significantly higher in lake compared with river. The length and weight of the infected fish were between 9 and 33 cm, and between 20 and 760 g respectively. There was a significant and positive strong correlation between the presence of S. agalactiae and fish mortalities in lake. All water quality parameters showed significant differences between river and lake. However, only water temperature, clarity and pH of lake and the ammonia, temperature and dissolved oxygen in river showed significant correlation with the presence of S. agalactiae in the cultured fish. It was concluded that several unfavourable water quality in the fish farm influencing the presence of S. agalactiae in cultured red hybrid tilapia.  相似文献   

China's distant‐water fisheries in the 21st century     

Daniel Pauly  Dyhia Belhabib  Roland Blomeyer  William W W L Cheung  Andrés M Cisneros‐Montemayor  Duncan Copeland  Sarah Harper  Vicky W Y Lam  Yining Mai  Frédéric Le Manach  Henrik Österblom  Ka Man Mok  Liesbeth van der Meer  Antonio Sanz  Soohyun Shon  U Rashid Sumaila  Wilf Swartz  Reg Watson  Yunlei Zhai  Dirk Zeller 《Fish and Fisheries》2014,15(3):474-488

We conservatively estimate the distant‐water fleet catch of the People's Republic of China for 2000–2011, using a newly assembled database of reported occurrence of Chinese fishing vessels in various parts of the world and information on the annual catch by vessel type. Given the unreliability of official statistics, uncertainty of results was estimated through a regionally stratified Monte Carlo approach, which documents the presence and number of Chinese vessels in Exclusive Economic Zones and then multiplies these by the expected annual catch per vessel. We find that China, which over‐reports its domestic catch, substantially under‐reports the catch of its distant‐water fleets. This catch, estimated at 4.6 million t year^?1 (95% central distribution, 3.4–6.1 million t year^?1) from 2000 to 2011 (compared with an average of 368 000 t·year^?1 reported by China to FAO), corresponds to an ex‐vessel landed value of 8.93 billion € year^?1 (95% central distribution, 6.3–12.3 billion). Chinese distant‐water fleets extract the largest catch in African waters (3.1 million t year^?1, 95% central distribution, 2.0–4.4 million t), followed by Asia (1.0 million t year^?1, 0.56–1.5 million t), Oceania (198 000 t year^?1, 144 000–262 000 t), Central and South America (182 000 t year^?1, 94 000–299 000 t) and Antarctica (48 000 t year^?1, 8 000–129 000 t). The uncertainty of these estimates is relatively high, but several sources of inaccuracy could not be fully resolved given the constraints inherent in the underlying data and method, which also prevented us from distinguishing between legal and illegal catch.  相似文献   

Prospective study of avian influenza H9 infection in commercial poultry farms of Punjab Province and Islamabad Capital Territory,Pakistan     

Chaudhry  Mamoona  Ahmad  Maqbool  Rashid  Hamad Bin  Sultan  Bakhat  Chaudhry  Haroon Rashid  Riaz  Aayesha  Shaheen  Muhammad Shabir 《Tropical animal health and production》2017,49(1):213-220

Tropical Animal Health and Production - A prospective study was conducted from November 2013 to February 2014 to estimate the spatial clustering; cumulative incidence and risk factors associated...  相似文献   

Development and characterization of alginate-chitosan-hyaluronic acid (ACH) composite fibers for medical applications     

Tanveer Hussain  Rashid Masood  Muhammad Umar  Tanzeel Areeb  Azeem Ullah 《Fibers and Polymers》2016,17(11):1749-1756

Natural materials and plants have a long history of medical applications due to their broad range of favorable biological functions including biocompatibility, anti-bacterial, anti-oxidant and anti-inflammatory properties. Main objective of this study was to develop alginate-chitosan-hyaluronic acid (ACH) composite fibers with controlled drug release, and liquid retention properties for better moist wound healing. The dope comprising sodium alginate was extruded into calcium chloride (CaC1₂) coagulation bath. The developed calcium alginate fibers were then passed through a bath containing hydrolyzed chitosan and dip coated with hyaluronic acid for 24 hours. The resulting ACH composite fibers were then rinsed with deionized water and dried using acetone. These fibers were tested for tensile properties, % swelling, liquid absorption (g/g) and controlled drug release. The results concluded that ACH composite fibers can be produced by wet spinning and have adequate tensile properties, high % swelling, liquid absorption (g/g) and controlled release of hyaluronic acid for improved wound healing.  相似文献   

生防菌对向日葵列当的防除作用的初步研究     

郭振国  陈杰  MUHAMMAD Rashid Nizamani  陈连芳  马永清 《中国农业大学学报》2018,23(6):59-69

通过室内穴盘和连续两年遮雨棚盆栽试验,研究放线菌淡紫褐链霉菌(Streptomyces enissocaesilis,509),真菌灰黄青霉(Penicillium griseofulvum,CF3)和放线菌密旋链霉菌(Streptomyces pactum,Act12)3种生防菌对寄主植物向日葵的促生作用和对向日葵列当种子萌发的抑制作用。结果表明:1)CF3和Act12处理条件下,列当的出土数和寄生总数量显著降低,在新葵6号中CF3抑制列当寄生率高达74.4%,Act12抑制列当寄生率为68.7%,509抑制列当寄生率为53.0%;2)在列当寄生胁迫下,生防菌处理向日葵相比对照生物量有显著的增高,根冠比显著增大,含水量显著升高,生防菌处理的向日葵地上部和根的含水量≥70%。本研究表明CF3和Act12具有作为防除向日葵列当优良生防菌种的可能性。  相似文献   

Improvement of “Kinnow” mandarin fruit productivity and quality by urea,boron and zinc foliar spray     

Rashid S. Al-Obeed  Hassan A. Kassem  Adel M. Al-Saif 《Journal of plant nutrition》2018,41(5):609-618

The present study was carried out on Kinnow mandarin trees (Citrus reticulata Blanco) to study the effect of urea, zinc (Zn) and boron (B) foliar sprays either alone or in combinations on fruit yield and quality. Trees were grown in alkaline sandy loam soil at Dirab, Riyadh, Saudi Arabia. All trees were sprayed twice: before full bloom (February) and after fruit set (April) during two growing seasons. The obtained results showed a significant increase in tree yield and enhancement in fruit physical characteristics (fruit weight, pulp, juice, volume, length and diameter), as well as fruit chemical characteristics [soluble solids content, acidity, pH, total sugars and ascorbic acid] by all foliar treatments in comparison with the control (water only) in both seasons. Spraying urea in combinations with B and Zn resulted in higher fruit yield and better physico-chemical characteristics as compared with urea only, urea + B or urea + Zn.  相似文献   

Foliar calcium spray confers drought stress tolerance in maize via modulation of plant growth,water relations,proline content and hydrogen peroxide activity     

Muhammad Naeem  Muhammad Shahbaz Naeem  Rashid Ahmad  Muhammad Zahid Ihsan  Muhammad Yasin Ashraf  Yasir Hussain 《Archives of Agronomy and Soil Science》2018,64(1):116-131

Water and nutrient restrictions are the factors that limiting growth of maize in arid/semi-arid climate. Calcium (Ca²⁺) uptake is affected severely under drought stress (DS). The objectives of this study were to investigate the effects of DS and foliar applied Ca²⁺ on growth, physiological, biochemical, yield and grain-nutrient content in two maize cultivars i.e. drought-tolerantDekalb-6525 and drought-sensitive Yousafwala-hybrid. The study comprised of two phases; firstly the best rate of Ca²⁺ (20, 40 and 60 mg L?1) was evaluated. Secondly, optimized rate of Ca²⁺ (40 mg L?1) was used to assess physio-biochemical and yield responses of maize under DS. The applied DS caused significant reduction in maize growth, water-status, photosynthesis and grain nutrient contents. Foliar Ca²⁺ markedly improved plant growth, water-potential (18%), turgor-potential (75%), photosynthesis (45%), stomatal-conductance (47%), transpiration rate (43%) and accumulation of total soluble sugars (20%) along with decline in H2O2 content (23%) in both cultivars under DS. Furthermore, optimized rate of Ca²⁺ improved maize grain yield and quality under water-deficit conditions. Cultivar Dekalb-6525 presented significant response to Ca²⁺ over Yousafwala-hybrid. Results of the study surmise that foliar supply of Ca²⁺ is an effective approach to make plants vigorous to thrive under limited-water supply.  相似文献