Modeling of acoustic reverberation from a diurnally migrating fish aggregation with depth‐dependent resonance.

2010 ◽  
Vol 128 (4) ◽  
pp. 2279-2279
Author(s):  
Benjamin A. Jones ◽  
Timothy K. Stanton ◽  
John A. Colosi
1993 ◽  
Author(s):  
Jerald W. Caruthers ◽  
J. R. Fricke ◽  
Ralph A. Stephen

1993 ◽  
Vol 50 (1) ◽  
pp. 66-73 ◽  
Author(s):  
Mark R. S. Johannes

Aggregations of prey fish, golden shiner (Notemigonus crysoleucas), were examined during 7 yr of predator manipulations in two lakes to determine whether they responded to changes in predation pressure and varied with time-of-day, age, and habitat. Regression analysis was used to examine aggregation in 12 replicate prey densities from two time periods, two ages, two habitats, three sample series, and seven predator densities. Aggregation was assessed as the variance of mean densities for each treatment combination. Multiple regression and ANCOVA analyses indicated that (1) golden shiner aggregated more during day than night, (2) their aggregation was positively related to predator density, (3) young shiner aggregated more than older ones at low predator densities, and (4) aggregation in older shiner was more responsive to increased predator densities than aggregation in younger shiner. These results provide empirical evidence that golden shiner aggregation patterns respond to predation pressure and the response varies with time and age. These results also suggest that variance in net catches can provide an index of fish aggregation and that aggregation observed at the population level is not solely dependent on species and density, but is a behavioural response mediated by several factors including predators.


2021 ◽  
Author(s):  
Raja Azizah Raja Yeop ◽  
Sian Chin Tan ◽  
Ariff Irfan Zainai

Abstract This paper is to demonstrate the significance of structured planning, holistic assessment and synergies, as key value drivers in enabling and shaping decommissioning alternatives leading to sustainable decommissioning and circular economy. PETRONAS as the regulator of Malaysia's Upstream activities manage decommissioning obligations through Production Sharing Contracts, internal guidelines and other relevant procedures and standards. The Decommissioning Options Assessment (DOA) is the process used to land on the most feasible option. Throughout PETRONAS’ 18-year decommissioning journey thus far, decommissioning projects were successfully executed using various alternatives. The valuable learnings gained are applied to further strengthen our decommissioning processes in regulating, enabling and shaping future executions at the lowest cost with safety of life and protection of the environment as our utmost priority. Upon a decision to proceed with decommissioning, a gated technical review process is used as the governing process to ensure safety, protection to the environment and cost efficiency. It is during this gated technical review that DOA is conducted. The output from the DOA is deliberated within the ambit of five (5) key criteria, i.e. Health, Safety & Security, Environment, Society, Technical & Operational, and Economy. Upon completion of execution, lessons learnt coupled with findings from post-decommissioning surveys are analyzed and applied to future projects. Synergies and collaborations are key drivers in shaping sustainable and replicable alternative decommissioning solutions. PETRONAS continuously pursues strategic collaborations with all stakeholders, including but not limited to, government ministries/agencies, academia, and industry players to tap into global decommissioning solutions, scientific researches, technologies, and best practices. This key lever will be discussed in the paper. From actual experiences, supported by studies, it is evident that decommissioning alternatives, including Rigs-to-Reef, add value in terms of marine habitat protection, biodiversity enhancement, fish aggregation, etc. It has also contributed positively to the livelihoods and well-being of society. Re-using platforms for new field development maximizes value by extending the platform's useful life. In addition, PETRONAS also advocates the ‘design for decommissioning’ mindset during a field's development phase in achieving a robust life cycle cost. PETRONAS further believes the values gained from these decommissioning alternatives will contribute to the decommissioning ecosystem in Malaysia. Moving forward, PETRONAS aspires to elevate the sustainable decommissioning model with the mindset that, ‘no single piece of an abandoned structure goes to waste’. There is a need to mature studies, collaborations and supply chain readiness in realizing more options on the 3Rs (Reduce, Re-use and Recycle).


2019 ◽  
Vol 212 ◽  
pp. 35-39 ◽  
Author(s):  
Morteza Eighani ◽  
Seyed Yousef Paighambari ◽  
Marc Taquet ◽  
Jean-Claude Gaertner

2020 ◽  
Vol 152 ◽  
pp. 110928 ◽  
Author(s):  
Pierpaolo Consoli ◽  
Mauro Sinopoli ◽  
Alan Deidun ◽  
Simonepietro Canese ◽  
Claudio Berti ◽  
...  

2011 ◽  
Vol 68 (4) ◽  
pp. 651-666 ◽  
Author(s):  
Emmanuel Chassot ◽  
Sylvain Bonhommeau ◽  
Gabriel Reygondeau ◽  
Karen Nieto ◽  
Jeffrey J. Polovina ◽  
...  

Abstract Chassot, E., Bonhommeau, S., Reygondeau, G., Nieto, K., Polovina, J. J., Huret, M., Dulvy, N. K., and Demarcq, H. 2011. Satellite remote sensing for an ecosystem approach to fisheries management. – ICES Journal of Marine Science, 68: 651–666. Satellite remote sensing (SRS) of the marine environment has become instrumental in ecology for environmental monitoring and impact assessment, and it is a promising tool for conservation issues. In the context of an ecosystem approach to fisheries management (EAFM), global, daily, systematic, high-resolution images obtained from satellites provide a good data source for incorporating habitat considerations into marine fish population dynamics. An overview of the most common SRS datasets available to fishery scientists and state-of-the-art data-processing methods is presented, focusing on recently developed techniques for detecting mesoscale features such as eddies, fronts, filaments, and river plumes of major importance in productivity enhancement and associated fish aggregation. A comprehensive review of remotely sensed data applications in fisheries over the past three decades for investigating the relationships between oceanographic conditions and marine resources is provided, emphasizing how synoptic and information-rich SRS data have become instrumental in ecological analyses at community and ecosystem scales. Finally, SRS data, in conjunction with automated in situ data-acquisition systems, can provide the scientific community with a major source of information for ecosystem modelling, a key tool for implementing an EAFM.


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