Post-larval recruitment of blacklip abalone (Haliotis rubra) on artificial collectors in southern Tasmania

1995 ◽  
Vol 46 (3) ◽  
pp. 531 ◽  
Author(s):  
WJ Nash ◽  
JC Sanderson ◽  
J Bridley ◽  
S Dickson ◽  
B Hislop
Keyword(s):  
Sea Water ◽  
Larval Settlement ◽  
Water System ◽  
Early Spring ◽  
Larval Abundance ◽  
Second Phase ◽  
Larval Recruitment ◽  
Stage Process ◽  
Flow Through ◽  
Haliotis Rubra

Recruitment rates of blacklip abalone (Haliotis rubra) post-larvae were measured at fortnightly intervals for a year in southern Tasmania on larval collectors made of transparent, corrugated plastic. The settlement plates were conditioned prior to use in a flow-through sea-water system in a two-stage process. A film of diatoms (mainly Nitzschia and Navicula species) was first established on the plates, which were then grazed by juvenile H. rubra. This allowed second-phase algae (principally Myrionema species) to become established. The plates were then periodically deployed at a depth of ~7 m. Larval settlement occurred mainly during the austral winter and early spring. A peak settlement rate of 1408 post-larvae per collector (2347 post-larvae m-2) occurred in mid August. Methods of measuring larval or immediate post-larval abundance are reviewed with regard to their use in the assessment and management of abalone fisheries.

scholarly journals REARING OF JUVENILE DONKEY-EAR ABALONE (Haliotis asinina) IN FLOW-THROUGH TANKS WITH THE ADDITION OF DIFFERENT SUBSTRATES

2015 ◽  
Vol 40 (1) ◽  
pp. 17-22
Author(s):  
Dwi Eny Djoko Setyono
Keyword(s):  
Body Weight ◽  
Growth Rates ◽  
Shell Length ◽  
Sea Water ◽  
Survival Rates ◽  
Water System ◽  
Daily Growth ◽  
Coral Rubble ◽  
Haliotis Asinina ◽  
Flow Through

This study investigated the effects of the addition of coral rubble and polyvinylchloride (PVC) guttering as substrates on the growth of donkey-ear abalone (Haliotis asinina) reared in a flow-through water system. The tanks were100 cm long x 50 cm wide x 40 cm deep, filled with sea water up to 30 cm high. Hatchery-produced abalone with a mean initial shell length of 30.9 ± 0.1 mm and wet weight of 5.5 ± 0.1 g were stocked at 25 individuals/tankthat corresponded to stocking densities of ca. 50 abalone/m2 of the bottom area of the tank. Juvenile abalonewere provided with an excess red seaweed Gracilaria spp daily over 175 days. The results show that growth and growth rates in shell length and wet body weight were not significantly different between treatments (P>0.05). Survival rates of juveniles reared in the tank with the addition of coral rubble and/or PVC guttering were 100%, but 98% for juveniles in the tank without the addition of substrate. The average daily growth rates of shell length and wet body weight were 0.087+0.037 mm and 0.088+0.044 g for juveniles reared in the tank with the addition of coral rubble; 0.081+0.030 mm and 0.077+0.032 g for juveniles reared in the tank with the addition of PVC guttering; and 0.082+0.032 mm and 0.078+0.039 g for juveniles reared in tank without addition of substrates.

The influence of hydrological pathways on the transport of the herbicide, isoproturon, through an underdrained clay soil

1999 ◽  
Vol 39 (12) ◽  
pp. 77-84 ◽  
Author(s):  
C. M. Heppell ◽  
T. P. Burt ◽  
R. J. Williams ◽  
A. H. Haria
Keyword(s):  
Surface Waters ◽  
Clay Soil ◽  
Quality Standard ◽  
Early Spring ◽  
Hydrological Response ◽  
Macropore Flow ◽  
Ephemeral Stream ◽  
Low Intensity ◽  
Flow Through ◽  
High Concentrations

This paper reports the findings of a 12 month field monitoring programme at Wytham (Oxfordshire, UK), which examined the leaching of the phenylurea herbicide, isoproturon, from an agricultural clay hillslope to the adjacent ephemeral stream. Isoproturon was shown to reach the drains (at 50 cm depth) through a combination of vertical and lateral macropore flow through wormholes and inter-pedal cracks. Seasonal changes in hydrological response were also observed at the site, with lateral flow through inter-pedal cracks providing an important route by which herbicide was transported during autumn and early spring when the clay soils were wetting up. Concentrations of isoproturon in drainflow frequently exceeded the Environment Agency's (EA) non-statutory Environmental Quality Standard (EQS) of 20 μg/l for isoproturon in surface waters. Even under low intensity rainfall (< 1 mm/hr) the saturated region at the base of the hillslope was shown to conduct macropore flow containing significantly high concentrations of herbicide to the drain. The results of this study suggest that those regions close to surface waters which are areas of converging hydrological flow may be key contributors to the problem of isoproturon contamination of surface waters.

scholarly journals Coastal winds drive a recruitment mechanism for estuarine fisheries

2020 ◽  
Author(s):  
Hayden T. Schilling ◽  
Charles Hinchliffe ◽  
Jonathan P. Gillson ◽  
Anthony Miskiewicz ◽  
Iain M. Suthers
Keyword(s):  
Larval Fish ◽  
Future Research ◽  
Larval Abundance ◽  
Spawning Period ◽  
Onshore Wind ◽  
Larval Recruitment ◽  
Australian Region ◽  
Coastal Winds ◽  
Key Driver ◽  
Catch Rates

AbstractCoastal winds transport larval fish onshore or offshore which may contribute to estuarine recruitment, yet our understanding of the mechanism underlying this relationship is limited. Here, we show that larval abundance of coastally spawned species increased with weak to moderate upwelling favourable winds 14 days prior to sampling, reflecting increased nutrient and plankton availability for larval fish. A strong decline in larval abundance was observed following strong upwelling favourable winds while abundance increased with onshore (downwelling favourable) winds, in relation to offshore and onshore wind-driven transport. Subsequently, we show that effects of wind during the spawning period can be detected in lagged estuarine commercial fisheries catch rates of coastally spawned species (lagged by 2 – 8 years depending on species’ growth rates), representing the same mechanism proposed for larval fish. Upwelling favourable winds in the southeast Australian region have increased since 1850 while onshore winds have decreased, which may reduce larval recruitment to estuaries. Coastal winds are likely an important factor for estuarine recruitment in the east Australian region and future research on the estuarine recruitment of fish should incorporate coastal winds. As global winds are changing, it is important to investigate if this mechanism is applicable to other regions around the world where coastal winds are a key driver of upwelling.

Blood oxygen transport and metabolism of the confined lugworm Arenicola marina (L.)

1975 ◽  
Vol 63 (3) ◽  
pp. 647-660
Author(s):  
A. Toulmond
Keyword(s):  
Anaerobic Metabolism ◽  
Sea Water ◽  
Blood Oxygen ◽  
Total Blood ◽  
Oxygen Saturation Level ◽  
Gas Exchanges ◽  
Water Oxygen ◽  
Buffer Power ◽  
Flow Through ◽  
Total Blood Flow

Oxygen consumption (MO2), haemoglobin oxygen saturation level (SVO2) and pH (pHv) in prebranchial blood were measured in lugworms experimentally confined in sea water at 15 degrees C. Total blood flow through the gills (Vb) was estimated. For sea water oxygen partial pressure (PwO2) between 120 and 150 Torr MO2, SVO2 and Vb were high and nearly constant. For PwO2 less than 120 Torr, Vb fell quickly, MO2 progressively dropped, and metabolism remained aerobic at the expense of the prebrancial blood oxygen store. For PwO2 less than 50 Torr, Vb and SvO2 values were extremely low, and the low pHv and the modified buffer power of the surrounding sea water showed that anaerobic metabolism was occurring. Changes in respiratory gas exchanges and metabolism during the tidal cycle are deduced from the comparison of these results with data obtained in the field.

Growth of four species of juvenile fish associated with the Seagrass Zostera capricorni, in Botany Bay, NSW

1992 ◽  
Vol 43 (5) ◽  
pp. 1189 ◽  
Author(s):  
DG Worthington ◽  
DJ Ferrell ◽  
SE NcNeill ◽  
JD Bell
Keyword(s):  
Sea Water ◽  
New South ◽  
Juvenile Fish ◽  
Natural Populations ◽  
Length Frequency ◽  
Frequency Distributions ◽  
South Wales ◽  
Time Period ◽  
Flow Through ◽  
Sampling Programme

Populations of four species of juvenile fish- Rhabdosargus sarba, Acanthopagrus australis, Achoerodus viridis and Girella tricuspidata-were sampled from a seagrass bed in Botany Bay, New South Wales. Fish were collected eight times between 22 March 1990 and 22 February 1991, using a small seine-net. Growth rates were calculated from the progression of cohorts in length-frequency distributions. Cohorts of R. sarba, A. australis and A. viridis grew most slowly during winter (0.02, 0.04 and 0.21 mm day-1, respectively); growth then increased, peaking just prior to the loss of the cohort from the habitat (0.3 1, 0.24 and 0.39 mm day-1). Populations of R. sarba, A. australis and A. viridis were comprised of one or two cohorts that remained in the habitat for at least 3-4 months. Conversely, up to seven cohorts of G. tricuspidata were found between October and February, and most cohorts did not remain in the habitat for more than 2 months. As a result, there were only two confident estimates of growth for G. tricuspidata: 0.23 mm day-1 between October and November, and 0.34 mm day-1 between January and February. Individuals of each species were also kept in a flow-through 4000-L tank of sea water. Growth of cohorts of fish kept in the tank was very similar to that found in natural populations during the same time period. The rates of recruitment and loss of cohorts from seagrass can be rapid and these factors must be considered in designing a sampling programme to assess growth by analysis of length-frequency distributions.

scholarly journals Contamination of Trichloroethylene in Drinking Water System and Its Degradation

2012 ◽  
Vol 3 ◽  
pp. 13-17 ◽  
Author(s):  
Devi Lal Adhikari ◽  
Chikashi Sato ◽  
Shobha Kanta Lamichhane
Keyword(s):  
Drinking Water ◽  
Titanium Dioxide ◽  
Ultraviolet Light ◽  
Water System ◽  
Ultrasonic Waves ◽  
Produce Water ◽  
Drinking Water Standard ◽  
Drinking Water System ◽  
Flow Through ◽  
System Water

Photolysis and sonolysis of trichloroethylene (TCE) in water was investigated using a cup-horn, flow-through reactor system. Water containing titanium dioxide was deliberately contaminated with TCE. These solutions were irradiated with ultraviolet light (UV) and ultrasonic waves (US). The decrease in the TCE concentration was observed in water under both US and UV treatments. Present findings declare that the use of UV and US decreased the TCE concentration. With the reactor specifications used, the photolysis and sonolysis processes can produce water meeting the drinking water standard (MCLs of 5?g/L) for TCE.The Himalayan PhysicsVol. 3, No. 32012Page : 13-17

Hydraulic Model Calibration of a Nuclear Plant Service Water System

2016 ◽  
Author(s):  
Erin A. Onat ◽  
Trey W. Walters ◽  
David M. Mobley ◽  
James J. Mead
Keyword(s):  
Water System ◽  
Complete Data ◽  
Second Phase ◽  
Data Set ◽  
Flow Rates ◽  
Pressure Drops ◽  
Calibration Process ◽  
Partial Data ◽  
Service Water ◽  
Data Calibration

As pipe networks age, build-up [scaling] and corrosion decrease pipe diameter and increase pipe roughness, leading to significant pressure drops and lower flow rates. When modeling the hydraulics of these systems, calibrating the pipes to account for additional scaling and/or fouling can be vital to accurately predicting the hydraulic behavior of the system. An automated, multi-variable goal-seeking software was used to calibrate the raw water system of the Duke McGuire Nuclear Station (MNS). This calibration process involved three phases. The first phase was the testing of the automated, multivariable goal-seeking software on a previously calibrated system. The second phase was the calibration of a partial data set. The third phase was the calibration of a complete data set. The automated goal-seeking software was found to have varying degrees of success in each phase. At the conclusion of the calibration process, the partial data calibration of two parallel systems at MNS yielded average overall calibration accuracies of 2.1% and 1% for flow rates, and 1.2 psig (8.4 kPa-g) and 1.7 psig (11.9 kPa-g) for pressures. The complete data calibration of one of these systems at MNS yielded an average overall calibration accuracy of 2.3% for flow rates, and 1.4 psig (9.5 kPa-g) for pressures.

Application and Experience Feedback of ASME Code Case N-155-2 for RTR Piping in Nuclear Plants

2013 ◽  
Author(s):  
Nicolas d’Udekem ◽  
Philippe Art ◽  
Jacques Grisel
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Sea Water ◽  
Water System ◽  
Moderate Pressure ◽  
Raw Water ◽  
Cooling Systems ◽  
Piping Systems ◽  
Asme Code

Nowadays, the usefulness of RTR (Reinforced Thermosetting Resin) for pressure retaining equipment does not need further proof: they are lightweight, strong, with low thermal elongation and highly corrosion resistant. The use of RTR piping makes all sense for piping systems circulating raw water such as sea water at moderate pressure and temperature for plants cooling. However, this material is rarely used for safety related cooling systems in nuclear power plants. In Belgium, Electrabel and Tractebel have chosen to replace the existing carbon steel pipes of the raw water system by GRE (Glassfiber Reinforced Epoxy) pipes, in accordance with the Authorized Inspection Agency, applying the ASME Code Case (CC) N-155-2 defining the specifications and requirements for the use of RTR pipes, fittings and flanges. After a challenging qualification process, Class 3 GRE pipes are now installed and operating for raw water cooling systems in two Belgian nuclear units and will soon be installed in a third one. The paper will address the followed qualification processes and the implementation steps applied by Electrabel/Tractebel and relate the overcome obstacles encountered during manufacturing, erection and commissioning of Class 3 GRE piping in order to ensure quality, reliability and traceability required for safety equipment in nuclear power plants.

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