White spot syndrome virus (WSSV) transmission risk through infected cooked shrimp products assessed by polymerase chain reaction (PCR) and bio-inoculation studies

The aim of the study was to evaluate the resistance of white spot syndrome virus (WSSV) in shrimps (Penaeus monodon) to the process of cooking. The cooking was carried out at 1000C six different durations 5, 10, 15, 20, 25 and 30 min. The presence of WSSV was tested by single step and nested polymerase chain reaction (PCR). In the single step PCR, the primers 1s5 & 1a16 and IK1 & IK2 were used. While in the nested PCR, primers IK1 &IK2 – IK3 & IK4 were used for the detection of WSSV. WSSV was detected in the single step PCR with the primers 1s5 and 1a16 and the nested PCR with the primers IK1 and IK2 – IK3 & IK4 from the cooked shrimp samples. The cooked shrimps, which gave positive results for WSSV by PCR, were further confirmed for the viability of WSSV by conducting the bio-inoculation studies. Mortality (100%) was observed within 123 h of intra-muscular post injection (P.I) into the live healthy WSSV-free shrimps (P. monodon). These results show that the WSSV survive the cooking process and even infected cooked shrimp products may pose a transmission risk for WSSV to the native shrimp farming systems.

Characterizing a cyanobacterial bloom in western Lake Erie using satellite imagery and meteorological data

The distribution and intensity of a bloom of the toxic cyanobacterium, Microcystis aeruginosa, in western Lake Erie was characterized using a combination of satellite ocean-color imagery, field data, and meteorological observations. The bloom was first identified by satellite on 14 August 2008 and persisted for more than 2 months. The distribution and intensity of the bloom was estimated using a satellite algorithm that is sensitive to near-surface concentrations of M. aeruginosa. Increases in both area and intensity were most pronounced for wind stress less than 0.05 Pa. Area increased while intensity did not change for wind stresses of 0.05–0.1 Pa, and both decreased for wind stress greater than 0.1 Pa. The recovery in intensity at the surface after strong wind events indicated that high wind stress mixed the bloom through the water column and that it returned to the surface once mixing stopped. This interaction is consistent with the understanding of the buoyancy of these blooms. Cloud cover (reduced light) may have a weak influence on intensity during calm conditions. While water temperature remained greater than 15°C, the bloom intensified if there were calm conditions. For water temperature less than 15°C, the bloom subsided under similar conditions. As a result, wind stress needs to be considered when interpreting satellite imagery of these blooms.

Successful inoculation of Artemia and production of cysts in the coastal saltpans of Bangladesh II

Bangladesh has no naturally occurring Artemia, and all the growing shrimp hatcheries of the country depend entirely on import of cysts from foreign countries. Following successful inoculation of Artemia and production of cysts for the first time in this country in a coastal saltpan (at Chanua, Banskhali) by the senior author (in 1989-90), a similar second attempt was made under this programme in a saltpan (1000 m super(2)) of Demoshia, Chakaria, Cox's Bazar, Bangladesh between January and April 1992. A total of 1639.9 g (dry weight) of cysts (i.e. 5.46 kg DW/ha/month) have been produced using the Red Jungle Brand, whereas the previous attempt obtained 517 g of cysts (i.e. 2.07 kg DW/ha/month) using the Great Salt Lake Brand.

Successful inoculation of Artemia and production of cysts in man-made salterns in the Philippines

The authors report on inoculation experiments of Artemia nauplii and young adults of the San Francisco Bay strains in earthen fish ponds. The test inoculated proved successful where water salinity ranges from 20 to 32 o/oo during the start of the rainy season in the Philippines.

Relative tolerance of mat-forming algae to copper

This study documents the relative tolerance of the common, weedy mat-forming green algae Hydrodictyon , Oedogonium , Pithophora , Rhizoclonium , and Spirogyra to copper. In addition, the copper tolerance of the cyanobacterial (blue-green algal) mat-forming Oscillatoria was assessed.

Ecophysiological perspectives of blue-green algal blooms

Blue-green algae (cyanobacteria) have had a profound and unparalled impact on the aquatic environment because of the phenomenon of bloom formation. In many countries, water management is threatened with extensive and persistent noxious blooms of blue-green algae in surface and near-surface mesotrophic and eutrophic waters. In view of this, ecological and physiological factors responsible for blue-green algal dominance are discussed. The implications of cyanobacterial blooms are highlighted and recommendations made to combat this menace

A decade of monitoring and management of freshwater algae, in particular Cyanobacteria, in England and Wales

Although the toxicity of cyanobacteria has been known for many years, cyanobacteria-related problems in the UK were generally limited in frequency. However, this all changed and became of national concern following the exceptional environmental conditions in the autumn of 1989, when widespread cyanobacterial blooms and scums developed in fresh waters. This paper summarises the Environment Agency's monitoring programme for freshwater algae since 1991 and describes the actions the Environment Agency has taken as a result of the monitoring data.

Scientific assessment of freshwater harmful algal blooms

In 2004, Congress reauthorized the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 with the Harmful Algal Bloom and Hypoxia Amendments Act (HABHRCA 2004). The 2004 legislation required the generation of five reports, including this "Scientific Assessment of Freshwater Harmful Algal Blooms." HABHRCA 2004 stipulates that this report 1) examine the causes, consequences, and economic costs of freshwater HABs, 2) establish priorities and guidelines for a research program on freshwater HABs, and 3) make recommendations to improve coordination among Federal agencies with respect to research on HABs in freshwater environments. This report is divided into five chapters: Chapter 1 provides the legislative background and process for developing the report, Chapter 2 describes the problem of freshwater and inland HABs in the United States, Chapter 3 outlines the current Federal efforts in freshwater and inland HAB research and response, Chapter 4 discusses the future research priorities, and Chapter 5 delineates opportunities for coordination to advance research efforts. The document is based, in large part, on the proceedings (Hudnell 2008) of the International Symposium on Cyanobacterial Harmful Algal Blooms, a meeting convened by EPA and sponsored by a variety of Federal agencies, to describe current scientific knowledge and identify priorities for future research on CyanoHABs. This report offers a plan for coordinating the important research that is currently ongoing in the United States and for guiding future research directions for Federal programs as well as for state, local, private, and academic institutions in order to maximize advancements. To this end, the Interagency Working Group on Harmful Algal Blooms, Hypoxia, and Human Health (IWG-4H) identifies seven priorities, all of equal weight, for freshwater HAB research and response. These priorities represent research areas where there is the greatest potential for progress in freshwater HAB research. This report does not attempt to assess the relative importance of freshwater HAB research compared to other research areas or other priorities for Federal or state investment.

Culture of Moina micrura on various organic waste products

Moina micrura, a cladoceran species, is considered to be one of the best live food organisms for rearing the young larval stages of fish and prawn. Considering the importance of this species in hatchery operations the present study was undertaken to record its fecundity and life span and to culture it using different locally available organic waste products. In indoor culture, a maximum production of 2600 ind/1 and a minimum of 1050 ind/1 were obtained when treated with gram + maize oilcake and "till" oilcake respectively. In outdoor culture, a highest production of 6000 ind/1 was achieved with "Alsi" and "till" oilcakes and a lowest density of 1050 ind/1 with coconut oilcake and raw cattle dung was obtained with an inoculation rate of 5 ind/1.

Pathogenicity of Aeromonas hydrophila artificially infected to Indian major carp (Cirrhinus mrigala Ham.)

Abrasion, feeding, injection and immersion methods were used to evaluate the pathogenicity of five different strains of Aeromonas hydrophila viz. RG (rui gill), ML (mrigal lesion), SG (sharpunti gill), F1K (mrigal kidney), GFL (gold fish lesion) and Ah-19 (Aeromonas hydrophila-19, Ref. Strain) against C. mrigala H. Bacterial suspension containing viable cells of 7.5x 10⁵ per ml was found to be very effective in intramuscular injection and feeding resulting 100% mortality after 96hr of inoculation. The strain RG, ML and F1K produced scale loss with erosion of the skin surface with/without hemorrhagic lesion after 48hr of inoculation following abrasion method. The strains SG and Ah-19 resulting scale loss with erosion of the skin surface with/without hemorrhagic lesion after 72hr of inoculation following abrasion and injection methods. SG and F1K caused reddening in mouth region after 72hr of feeding inoculation, whereas RG resulted frank ulcers from eroded dermal layer exposing underlying musculature which was hemorrhagic after 96hr of inoculation by abrasion method.

Survival of Staphylococci on frozen fish

Using Staphylococcus aureus as the test culture it has been shown that cell injury occurs in two phases during freezing and storage at temperatures below freezing. Certain constituents of fish muscle appear to protect the cells during both phases of injury. The survival of bacteria on fish muscle is not influenced by the rate at which the fish muscle was frozen prior to inoculation. There was no significant difference between growth of bacteria on quick frozen and slow frozen fish muscle after thawing. However there appeared to be a slight tendency for the lag phase of growth to be extended on thawed quick frozen fish muscle when compared with thawed slow frozen muscle.

Growth performances of three microalgal species in filtered brackishwater with different inorganic media

The growth of three microalgae species, viz., Nannochloropsis oculata, Tetraselmis chui and Chaetoceros muelleri which are commonly used in aquaculture, was investigated using three different inorganic nutrient media: (i) Modified Guillard's f/2 medium (ii) Rix Mix medium and (iii) BFRI medium. Each microalgae species was cultured for 24 days in small- scale with initial inoculation density of 17xl04 cell /ml in the three media with triplicates. N. oculata cultured in modified Guillard's f/2 medium showed superior growth with a mean peak density of 221 ±4.24 x 104 cell/ ml, to Rix Mix medium (141 ± 10.54xl04 cell/ml) and BFRI medium (47±4.94 x 104 cell/ml) on the 16th day of culture at stationary phase. Considering the increase in cell density for 20 days of culture in Rix Mix medium, C. muelleriwas significantly (P<0.05) highest than in other two media. N. oculata cultured in BFRI medium resulted in the poorest growth with a mean peak increase in density of 84±9.19 x 104 cell/ml in 12 days of culture. However, with an increase in cell density, growth of T. chui (182 ± 6.26 x 104 cell/ml) was significantly (P<0.05) higher in BFRI medium than in modified Guillard's f/2 medium. The results of the present study suggest that N. oculata and C. muelleri can be grown very well in both the modified Guillard's f/2 medium and Rix Mix medium. Better growth of T. chui can be obtained while culturing either in BFRI and Rix Mix medium. These three nutrient media used in the present study may be useful for microalgae species culture for establishing green-water culture for suitable target zooplankton, and fish and crustacean larvae in marine and brackishwater hatcheries.

Feasibility study of biofuel production from freshwater fern, Azolla sp in Anzali Wetland

Production of bioethanol through acidic and enzymatic hydrolysis of aquatic Azolla sp., as a new source of bio-mass, has been performed, as a means to control increasing growth and reducing undesirable effects of this plant in Anzali lagoon. After sampling, drying and crushing, Azolla was hydrolyzed, using diluted acid and enzyme. Diluted acid hydrolysis was done using both autoclave and a high-pressure system (Batch Synth® Microwave synthesizer). The effects of temperature and time (in autoclave) and concentration of acid (in both) were compared. Cellubrix®, a ommercial cellulase source, was used for enzymatic hydrolysis process. The amounts of reducing sugars, glucose and furfural, released from hydrolyzate, were measured. To produce alcohol, Sacchromyces cerevisiae (to ferment sixcarbon sugars), Zygowilliopsis californica and Pichia stipitis (to ferment five-carbon and sixcarbon sugars) were used. Maximum amounts of glucose (4.83% w/w) and reducing sugars (14.15% w/w) were obtained using acid hydrolysis in autoclave. In the microwave oven, maximum glucose (5.04% w/w) and reducing sugars (13.27 w/w) were obtained at 180 and 200 °C, respectively. Under these conditions, maximum produced furfural was 1.54 g/L. The difference between amounts of furfural obtained from acid hydrolysis of Azolla in microwave oven compared to autoclave was statistically significant. Amounts of alcohol produced and its yields were 3.99 g/L and 33.13% for S. cerevisiae in 48 hours, 3.73 g/L and 30.45% for Pichia stipites in 48 hours, and 3.73 g/L and 30.45% for Z. californica in 24 hours after inoculation, respectively, with significant differences. Statistical comparison of results showed significant differences (P<0.05) in glucose production, at different conditions. Amounts of reducing sugars and glucose increased after optimization of levels of acid, time, and temperature. The overall optimum released sugar and glucose were obtained with 1.67% (w/v) acid using autoclave. Higher temperatures in microwave oven caused a significant increase (P<0.05) in furfural. Furfural severely inhibits fermentation. Hence, regarding the issues of energy consumption and time, amounts of inhibiting substances and sugar production, autoclave is found to be superior to the high temperature and pressure, generated in microwave oven, for hydrolyzing Azolla. Furthermore, given the amounts of Azolla in Anzali lagoon, it may be recommendable to use this plant as a biomass resource.