Performance of bycatch reduction devices varies for chondrichthyan, reptile, and cetacean mitigation in demersal fish trawls: assimilating subsurface interactions and unaccounted mortality

2016 ◽  
Vol 74 (1) ◽  
pp. 343-358 ◽  
Author(s):  
Corey B. Wakefield ◽  
Julia Santana-Garcon ◽  
Stacey R. Dorman ◽  
Stuart Blight ◽  
Ainslie Denham ◽  
...  
Keyword(s):  
Electronic Monitoring ◽  
Bottlenose Dolphins ◽  
Cost Effective ◽  
Demersal Fish ◽  
Mitigation Strategies ◽  
Trawl Fishery ◽  
Bycatch Reduction ◽  
Cost Effective Method ◽  
Species Specific

To improve bycatch mitigation of chondrichthyans, reptiles and cetaceans for a tropical demersal fish-trawl fishery, species-specific responses to bycatch reduction devices (BRDs) were investigated using both in situ subsurface and onboard observations. There are few, if any, studies that have determined mitigation performances of BRDs from subsurface interactions for these species, as most are rarely encountered and thus require substantial levels of observer coverage for robust assessments. This study combined in-net and onboard (774 day trawls and 1320 day trawl hours of subsurface observer coverage) electronic monitoring on all fish-trawl vessels (n = 3) to compare bycatch mitigation performances among nine megafauna groups, based on escape rates and interaction durations for three BRDs over 6 months (June to December 2012). Overall, 26.9% of day trawls had no megafauna interactions and 38.3% of the 1826 interactions escaped, with most in rapid time (91.4% in ≤ 5 min). The upward inclined exclusion grid significantly improved the escape proportions for most chondrichthyans by 20–30%. All BRDs were highly effective in reducing reptile (turtles and seasnakes) bycatch, but irrelevant for the few sawfish (n = 13) that readily entangled in the anterior of the net. Cetacean (bottlenose dolphins only) interactions with BRDs were very rare (n = 7) despite high levels of attendance and depredation during trawling. Loss of targeted teleosts through the BRD hatch was rare (1.3% of day trawls). This relatively cost-effective method of electronic monitoring achieved very high levels of subsurface observer coverage (60% of day trawls or 56% of day trawl hours), and provided evidence that the subsurface expulsion of megafauna in poor condition is negligible. Furthermore, this study provides species-specific improvements toward bycatch mitigation strategies for demersal fish trawling.

scholarly journals Genome-wide markers reveal differentiation between and within the cryptic sister species, sunset and vermilion rockfish

2021 ◽  
Author(s):  
Gary C. Longo ◽  
John Harms ◽  
John R. Hyde ◽  
Matthew T. Craig ◽  
Ana Ramón-Laca ◽  
...  
Keyword(s):  
Management Strategies ◽  
Cost Effective ◽  
Sister Species ◽  
Nucleotide Polymorphisms ◽  
Relative Contribution ◽  
Genetic Groups ◽  
Cost Effective Method ◽  
Species Population ◽  
Single Complex ◽  
Species Specific

AbstractThe vermilion rockfish complex, which consists of the cryptic sister species vermilion and sunset rockfish, is one of the most valuable recreational fisheries on the U.S. West Coast. These species are currently managed as a single complex, and because of uncertainty surrounding the relative contribution of each species within existing data sources, the stock status of each species is not fully known. A reliable and cost-effective method is needed to disentangle these species that will allow for the development of abundance indices, life history profiles, and catch histories that may potentially support species-specific stock assessments. Using restriction-site associated DNA sequence (RADseq) markers we generated 10,003 polymorphic loci to characterize the vermilion rockfish complex. PCA and Bayesian clustering approaches based on these loci clearly distinguished between sunset and vermilion rockfishes and identified hybrid individuals. These loci included 203 highly differentiated (FST ≥ 0.99) single nucleotide polymorphisms, which we consider candidates in the planned development of a diagnostic assay capable of distinguishing between these cryptic species. In addition to clearly delineating to species, subsets of the interspecific markers allowed for insight into intraspecific differentiation in both species. Population genetic analyses for sunset rockfish identified two weakly divergent genetic groups with similar levels of genetic diversity. Vermilion rockfish, however, were characterized by three distinct genetic groups with much stronger signals of differentiation and significantly different genetic diversities. Collectively, these data will contribute to well-informed, species-specific management strategies to protect this valuable species complex.

Evaluation of maize microsatellite markers for genetic diversity analysis and fingerprinting in sugarcane

Genome ◽  
2003 ◽  
Vol 46 (3) ◽  
pp. 394-403 ◽  
Author(s):  
A Selvi ◽  
N V Nair ◽  
N Balasundaram ◽  
T Mohapatra
Keyword(s):  
Microsatellite Markers ◽  
Cost Effective ◽  
Diversity Analysis ◽  
Phenetic Analysis ◽  
Potential Cost ◽  
Banding Patterns ◽  
Genomic Libraries ◽  
Cost Effective Method ◽  
Low Diversity ◽  
Species Specific

The use of maize microsatellite markers as a potential cost-effective method for molecular analysis of sugarcane was evaluated. Of the 34 primer pairs obtained from maize genomic libraries, 14 showed repeatable amplifications in Saccharum species clones, commercial hybrids, and the related genera Erianthus, accounting for 41.17% cross transferability. Complex banding patterns were encountered in sugarcane with the number of amplified fragments ranging from 7 to 14 with an average of 10 per primer, indicating the high polyploidy and heterozygosity existing in sugarcane. Phenetic analysis of the SSR polymorphisms produced by nine primers could clearly differentiate the different species of Saccharum and Erianthus and revealed the relationships that existed between them. Genetic similarity co-efficient indicated low diversity existing among the S. officinarum clones (82%) and a relatively higher level of diversity in the S. spontaneum clones (69.7%). Higher level of divergence of Erianthus from Saccharum was also clearly estabilished. Five primers produced genus- and species-specific fragments for Erianthus, S. spontaneum, S. officinarum, and S. barberi. The polymorphic primers, when tested on a panel of 30 commercial sugarcane cultivars, revealed a broad range (32.4–83.3%) of pair-wise similarity values, indicating their ability to detect high levels of polymorphism. A combination of two primers could differentiate all the varieties, further emphasizing their potential in fingerprinting and varietal identification.Key words: maize microsatellites, Saccharum, Erianthus, diversity analysis, fingerprinting.

The Need for In-Situ Pipe Support Testing

2004 ◽  
Author(s):  
Gerry May
Keyword(s):  
Creep Damage ◽  
Cost Effective ◽  
Piping System ◽  
Design Load ◽  
Cost Effective Method ◽  
Accelerated Creep ◽  
Constant Support ◽  
Full Operation

Pipe support functionality is critical to the long term life of piping system. Spring supports degrade with time due to flexing in the spring and wear in constant support bearings. It is not unusual to measure constant support hangers with resistance 25% to 50% different than the design load. This leads to excessive sustained pipe stress, pipe sag (or uplift), and in high temperature systems, accelerated creep damage. Supports may also not move properly from shut down to full operation, which can create excessive fatigue stress, failed hanger components, and other piping system damage. In-situ hanger testing has been found to be a reliable and cost effective method to determine the functionality of pipe supports. Results are used as input to set revised recommended loads, and to determine if any hangers need to be replaced. This paper provides examples of the types of problems that are often found in the field, the method to test, and typical resolutions to maximize the pipe life and minimize the risk of failure.

scholarly journals ESTIMATING ABOVE GROUND BIOMASS OF <i>PINUS ROXBHURGHII</i> USING SLOPE BASED VEGETATION INDEX MODEL

2019 ◽  
Vol IV-5/W2 ◽  
pp. 35-42
Author(s):  
A. M. Joshi ◽  
S. Shahnawaz ◽  
B. Ranjit
Keyword(s):  
Vegetation Index ◽  
Cost Effective ◽  
Regression Equation ◽  
Pinus Roxburghii ◽  
Community Forests ◽  
Index Model ◽  
Cost Effective Method ◽  
Non Destructive ◽  
Planted Tree

Abstract. Pinus roxburghii is one of the important and most widely planted tree species in Nepal. Despite its large abundance and high economic values, limited studies on its AGB have been conducted in Nepal, especially using in situ non-destructive method. There are different methods to study the AGB. Regression equation based on the correlation between VI and AGB is cost effective method, and replicable in another sites of similar environment by just acquiring satellite images. Numerous methods have been developed to calculate VIs and each calculated VI shows different relation with AGB in different environments for same species. Therefore, there is a need to identify a most appropriate VI that has the highest correlation with AGB of P. roxburghii. The current study was carried out in Hattiban and Dollu community forests of Kathmandu district, using ResourceSat-2 imagery. In this study, Slope based VIs were used. Regression analysis between slope based VIs and AGB showed that relation between all VIs and AGB were significant. However, NDVI had the highest relation with AGB compared to others. Therefore, it was concluded that NDVI was the most appropriate VI to estimate AGB of P. roxburghii, and the regression equation with NDVI was used to estimate the AGB of P. roxburghii in the study area.

scholarly journals A review on phytoremediation as an ecological method for in situ clean up of heavy metals contaminated soils

2019 ◽  
Vol 112 ◽  
pp. 03024 ◽  
Author(s):  
Nicolae Cioica ◽  
Cătălina Tudora ◽  
Dorin Iuga ◽  
György Deak ◽  
Monica Matei ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Contaminated Soils ◽  
Crop Yields ◽  
Agricultural Soils ◽  
Animal Health ◽  
Cost Effective ◽  
Current State ◽  
Cost Effective Method ◽  
Excessive Accumulation

Heavy metals are among the most common types of contaminants in agricultural soils, especially those bordering the cities, due to the uncontrolled use of sewage sludge, compost, mining waste and chemical fertilizers. Excessive accumulation of heavy metals, which do not degrade over time, adversely affects crop yields by decreasing microbial activity and fertility of contaminated soils. Also, excess of heavy metals in the soil poses a serious threat to plant and animal health and, through their entry into the food chain, to human health. For this reason, the decontamination of soils contaminated with heavy metals has become a necessity. This review presents the current state of phytoremediation research as the most cost-effective method of in-situ environmental decontamination of soils contaminated with heavy metals.

Industry-collected target strength of high seas orange roughy in the Indian Ocean

2020 ◽  
Author(s):  
Ben Scoulding ◽  
Rudy Kloser
Keyword(s):  
Indian Ocean ◽  
Cost Effective ◽  
Measurement Range ◽  
Target Strength ◽  
Orange Roughy ◽  
Cost Effective Method ◽  
The Indian Ocean ◽  
State Of The Science ◽  
High Seas

Abstract Visually verified in situ target strengths (TS) are the state of the science for determining the conversion from acoustic echo-integration surveys to biomass. Here, we show how these measurements can be made by high seas fisheries during normal operations using a net-attached acoustic optical system (AOS) without specialized personnel on board. In situ TS were collected from ∼45 cm standard length (SL) orange roughy (Hoplostethus atlanticus) in the southern Indian Ocean at 38 and 120 kHz. We use a multiple lines of evidence approach to demonstrate that the previous TS–SL equation developed for ∼10 cm smaller fish in Australia and New Zealand is not suitable for the larger orange roughy and instead propose new TS–SL equations. Our findings show that biomass estimates at 38 kHz will be reduced by ∼58% when using this new TS–SL compared to the existing TS–SL for smaller fish. This highlights the error of extrapolating TS–SL equations outside the measurement range. For this high sea region, the net-attached AOS represented a practical cost-effective method to obtain measurements and provide a result that could be used to inform the management of the stocks. We suggest that this method would be useful in all deep-water fisheries to monitor the TS of the fish for a range of environmental and ontogenetic conditions.

scholarly journals Structural and Electrochemical Analysis of Decarburized Graphene Electrodes for Supercapacitor Applications

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1043
Author(s):  
Noor Zaman ◽  
Rizwan Ahmed Malik ◽  
Hussein Alrobei ◽  
Jaehwan Kim ◽  
Muhammad Latif ◽  
...  
Keyword(s):  
Nickel Foam ◽  
Cost Effective ◽  
Electrochemical Analysis ◽  
Multilayer Graphene ◽  
Supercapacitor Electrode ◽  
Large Intensity ◽  
Graphene Synthesis ◽  
Cost Effective Method ◽  
Carbon Precipitation

In this research, a facile and cost-effective method of graphene synthesis by the modified carburization process and its applications for supercapacitor electrodes is reported. In this simple approach, carbon was diffused into nickel foam and naturally cooled to obtain carbon precipitation for the in situ growth of graphene by decarburization. Phase-structure and surface-morphology analysis revealed the presence of a highly reduced structure of the graphene layer. Furthermore, the large-intensity D, substantial G, and 2D bands in Raman spectra were attributed to disordered multilayer graphene. The three-electrode systems were used to measure electrochemical efficiency. The electrode sample exhibited enhanced current density of 0.6 A/g, electrode energy of 1.0008 Wh/kg, and power density of 180 W/kg, showing significant electrochemical performance for supercapacitor electrode applications.

In-Situ Comparison of Bioremediation Methods for a Number 6 Residual Fuel Oil Spill in Lee County, Florida

1991 ◽  
Vol 1991 (1) ◽  
pp. 533-540 ◽  
Author(s):  
Mark A. Jones ◽  
Jeffrey H. Greenfield
Keyword(s):  
Feasibility Study ◽  
Cost Effective ◽  
Fuel Oil ◽  
Single Application ◽  
Residual Fuel Oil ◽  
Ring Compounds ◽  
Cost Effective Method ◽  
Enhanced Bioremediation ◽  
Small Plot

ABSTRACT On July 5, 1988, as a result of overfilling, about 3,200 barrels of No. 6 fuel was spilled onto surface soils surrounding a Florida Power and Light Company storage tank, and spread over about 60,000 square feet of soil. About 2,300 barrels were recovered, leaving 900 barrels in the upper six to eight inches of the soil. The spill was chosen as the site for a trial of in-situ enhanced bioremediation. An initial feasibility study in the laboratory was followed by groundwater monitoring, field remediation, and a small-plot research program. In the feasibility study, lower concentrations of nutrients applied periodically were almost as effective as a single application using a larger concentration. The small-plot study indicated that treatment with added bacteria and nutrients offered the greatest reduction in hydrocarbons. Addition of bacteria alone provided no advantage. In the field remediation program, two- and three-ring compounds were completely degraded, while four-, five-, and six-ring compounds were more resistant. The research demonstrated that in-situ enhanced bioremediation can be a cost-effective method for treating soils contaminated with No. 6 fuel oil.

scholarly journals Stable, Ductile and Strong Ultrafine HT-9 Steels via Large Strain Machining

Nanomaterials ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2538 ◽  
Author(s):  
Osman El-Atwani ◽  
Hyosim Kim ◽  
Jonathan G. Gigax ◽  
Cayla Harvey ◽  
Berk Aytuna ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Large Strain ◽  
Cost Effective ◽  
Industrial Applications ◽  
Excellent Thermal Stability ◽  
Transmission Electron ◽  
Cost Effective Method ◽  
Dislocation Densities ◽  
Thermal Stability Of

Beyond the current commercial materials, refining the grain size is among the proposed strategies to manufacture resilient materials for industrial applications demanding high resistance to severe environments. Here, large strain machining (LSM) was used to manufacture nanostructured HT-9 steel with enhanced thermal stability, mechanical properties, and ductility. Nanocrystalline HT-9 steels with different aspect rations are achieved. In-situ transmission electron microscopy annealing experiments demonstrated that the nanocrystalline grains have excellent thermal stability up to 700 °C with no additional elemental segregation on the grain boundaries other than the initial carbides, attributing the thermal stability of the LSM materials to the low dislocation densities and strains in the final microstructure. Nano-indentation and micro-tensile testing performed on the LSM material pre- and post-annealing demonstrated the possibility of tuning the material’s strength and ductility. The results expound on the possibility of manufacturing controlled nanocrystalline materials via a scalable and cost-effective method, albeit with additional fundamental understanding of the resultant morphology dependence on the LSM conditions.

ENVIRONMENTAL MANAGEMENT IN THE BASS STRAIT NORTHERN FIELDS 3D SEISMIC SURVEY

2003 ◽  
Vol 43 (1) ◽  
pp. 761
Author(s):  
S.H. Mustoe ◽  
M.C. Greenwood ◽  
J.F. Moore
Keyword(s):  
Best Practice ◽  
Cost Effective ◽  
Mitigation Strategies ◽  
Seismic Survey ◽  
3D Seismic ◽  
Seismic Surveys ◽  
Scallop Larvae ◽  
Spawning Periods ◽  
Large Survey

The Northern Fields 3D seismic survey in Bass Strait was a large survey of 4,000 km2, carried out between the months of October 2001 to July 2002. The program attracted interest from various groups regarding the possible impacts of the survey on fisheries and cetaceans (whales and dolphins).The survey was the first to operate in eastern Bass Strait after the Environment Australia Guidelines for Minimising Acoustic Disturbance to Whales, came into force, in September 2001.The Northern Fields program was conducted in accordance with a method statement for the mitigation of impacts to cetaceans, developed by Esso to meet the requirements of Australian environmental legislation and acknowledge environmental best practice. The program utilised teams of three whale watchers who maintained a continuous rotational watch of two observers throughout the day. This proved to be a reliable element of the program and was one of several key learnings that may assist other companies in developing comprehensive and cost-effective mitigation strategies for future surveys.Concerns raised by the fishing industry and some conservation groups about the potentially detrimental impact of seismic sources on commercial scallop larvae and fish populations were effectively addressed by avoiding commercial scallop areas during spawning periods. A controlled, in-situ study of scallops exposed to the acoustic source completed during the program conclusively demonstrated no significant variation in scallop mortality or muscle strength.Observation data collected during this survey provided a sample of the cetacean population in Eastern Bass Strait during a large part of the annual migration cycle. These observations, which may be relevant to the planning and execution of future seismic surveys in the region, are discussed. The findings also provide valuable information for continued research into the distribution and conservation of whales and dolphins in Bass Strait.

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