Long-distance migration of South African deep-water rock lobster Palinurus gilchristi

An experiment to investigate the potential of a trap-fishery for deep-water rock lobster Palinurus delagoae was conducted off the east coast of South Africa between 1994 and 1996. The 75–425 m depth interval between 27°S and 32°S was stratified according to depth and latitude, and three regions (North, Central and South) were sampled systematically over the three years. Sampling by commercial vessels operating long-lines and traps included an experimental phase (fixed fishing positions) and a commercial phase (no restriction on fishing location). Generalized linear models were used to investigate the influence of year, region, sampling phase, month and soak time. Sampling phase was significant, with traps set during the commercial phase catching more than those set in the experimental phase. The effect of soak time on catch rates was not significant. The almost-50% decrease in the combined abundance index combined with a marked decrease in mean lobster size over the study period suggests a relatively low fisheries potential for this species in South African waters; this may be attributable to the relative scarcity of suitable habitat in the area.

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Using a GLMM to estimate the somatic growth rate trend for male South African west coast rock lobster, Jasus lalandii

Fisheries Research ◽

10.1016/j.fishres.2004.08.012 ◽

2004 ◽

Vol 70 (2-3) ◽

pp. 339-349 ◽

Cited By ~ 10

Author(s):

A. Brandão ◽

D.S. Butterworth ◽

S.J. Johnston ◽

J.P. Glazer

Keyword(s):

Growth Rate ◽

South African ◽

West Coast ◽

Somatic Growth ◽

Rock Lobster ◽

Somatic Growth Rate

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Flow Assurance in Deep-Water Gas Pipelines: Locating Hydrate Plugging Position in a Fast Way

10.2118/205807-ms ◽

2021 ◽

Author(s):

Jing Yu ◽

Cheng Hui ◽

Chao Wen Sun ◽

Zhan Ling Zou ◽

Bin Lu Zhuo ◽

...

Keyword(s):

Pressure Drop ◽

Deep Water ◽

Pipe Wall ◽

Gas Pipeline ◽

Flow Assurance ◽

Gas Pipelines ◽

Long Distance ◽

Hydrate Layer ◽

Hydrate Deposition ◽

Water Gas

Abstract Hydrate-associated issues are of great significance to the oil and gas sector when advancing the development of offshore reservoir. Gas hydrate is easy to form under the condition featuring depressed temperature and elevated pressure within deep-water gas pipeline. Once hydrate deposition is formed within the pipelines, the energy transmission efficiency will be greatly reduced. An accurate prediction of hydrate-obstruction-development behavior will assist flow-assurance engineers to cultivate resource-conserving and environment-friendly strategies for managing hydrate. Based on the long-distance transportation characteristics of deep-water gas pipeline, a quantitative prediction method is expected to explain the hydrate-obstruction-formation behavior in deep-water gas pipeline throughout the production of deep-water gas well. Through a deep analysis of the features of hydrate shaping and precipitation at various locations inside the system, the advised method can quantitatively foresee the dangerous position and intensity of hydrate obstruction. The time from the start of production to the dramatic change of pressure drop brought about by the deposition of hydrate attached to the pipe wall is defined as the Hydrate Plugging Alarm Window (HPAW), which provides guidance for the subsequent hydrate treatment. Case study of deep-water gas pipeline constructed in the South China Sea is performed with the advised method. The simulation outcomes show that hydrates shape and deposit along pipe wall, constructing an endlessly and inconsistently developing hydrate layer, which restricts the pipe, raises the pressure drop, and ultimately leads to obstruction. At the area of 700m-3200m away from the pipeline inlet, the hydrate layer develops all the more swiftly, which points to the region of high risk of obstruction. As the gas-flow rate increases, the period needed for the system to shape hydrate obstruction becomes less. The narrower the internal diameter of the pipeline is, the more severe risk of hydrate obstruction will occur. The HPAW is 100 days under the case conditions. As the concentration of hydrate inhibitor rises, the region inside the system that tallies with the hydrate phase equilibrium conditions progressively reduces and the hydrate deposition rate slows down. The advised method will support operators to define the location of hydrate inhibitor injection within a shorter period in comparison to the conventional method. This work will deliver key instructions for locating the hydrate plugging position in a fast way in addition to solving the problem of hydrate flow assurance in deep-water gas pipelines at a reduced cost.

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Systematic placement of an enigmatic Southeast Asian taxon Eupetes macrocerus and implications for the biogeography of a main songbird radiation, the Passerida

Biology Letters ◽

10.1098/rsbl.2007.0054 ◽

2007 ◽

Vol 3 (3) ◽

pp. 323-326 ◽

Cited By ~ 26

Author(s):

Knud A Jønsson ◽

Jon Fjeldså ◽

Per G.P Ericson ◽

Martin Irestedt

Keyword(s):

South African ◽

Plate Tectonics ◽

Molecular Data ◽

Sister Taxon ◽

Long Distance ◽

Biogeographic History ◽

Basal Group ◽

History Of ◽

Biogeographic Regions ◽

Wallace’S Line

Biogeographic connections between Australia and other continents are still poorly understood although the plate tectonics of the Indo-Pacific region is now well described. Eupetes macrocerus is an enigmatic taxon distributed in a small area on the Malay Peninsula and on Sumatra and Borneo. It has generally been associated with Ptilorrhoa in New Guinea on the other side of Wallace's Line, but a relationship with the West African Picathartes has also been suggested. Using three nuclear markers, we demonstrate that Eupetes is the sister taxon of the South African genus Chaetops , and their sister taxon in turn being Picathartes , with a divergence in the Eocene. Thus, this clade is distributed in remote corners of Africa and Asia, which makes the biogeographic history of these birds very intriguing. The most parsimonious explanation would be that they represent a relictual basal group in the Passerida clade established after a long-distance dispersal from the Australo-Papuan region to Africa. Many earlier taxonomic arrangements may have been based on assumptions about relationships with similar-looking forms in the same, or adjacent, biogeographic regions, and revisions with molecular data may uncover such cases of neglect of ancient relictual patterns reflecting past connections between the continents.

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Impact of climate change and industrialization on remote Lake Bolshoe Toko, Siberia

10.5194/egusphere-egu21-10887 ◽

2021 ◽

Author(s):

Boris K. Biskaborn ◽

Biljana Narancic ◽

Kathleen R. Stoof-Leichsenring ◽

Lyudmila A. Pestryakova ◽

Peter G. Appleby ◽

...

Keyword(s):

Climate Change ◽

Deep Water ◽

Boreal Lakes ◽

Sediment Geochemistry ◽

Long Distance ◽

Lake Ecosystems ◽

Planktonic Diatoms ◽

Recent Climate Change ◽

Recent Climate ◽

Remote Lake

To test if recent climate change and pollution affected remote lake ecosystems without direct human influence, we used paleolimnological methods on lake sediments from a large, prestine, and deep lake in Yakutia, Russia. We compared diatoms and sediment-geochemistry from before and after the onset of industrialization in the mid-nineteenth century, at water depths between 12.1 and 68.3 m in Lake Bolshoe Toko. We analyzed diatom species changes and geochemical changes including mercury concentrations. Chronologies were established using 210Pb and 137Cs revealing sedimentation rates between 0.018 and 0.033 cm y-1 at shallow- and deep-water sites, respectively. Increase in light planktonic diatoms (Cyclotella) and decrease in heavily silicified euplanktonic Aulacoseira through time at deep-water sites can be related to warming air temperatures and shorter periods of lake-ice cover, causing pronounced thermal stratification. Diatom beta diversity changed only significantly in shallow-water communities which can be related to the development of new habitats with macrophyte growth. Mercury concentrations increased by a factor of 1.6 as a result of atmospheric fallout. Increases in the chrysophyte Mallomonas indicates a trend towards acidification. We conclude that also remote boreal lakes are susceptible to human-induced long-distance pollution and recent climate change.

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Population structure and morphology of South African deep‐water parapagurid hermit crabs

Acta Zoologica ◽

10.1111/azo.12288 ◽

2019 ◽

Vol 101 (3) ◽

pp. 227-241

Author(s):

Amy G. Wright ◽

Charles L. Griffiths ◽

Thomas P. A. Botha

Keyword(s):

Population Structure ◽

South African ◽

Deep Water ◽

Hermit Crabs ◽

Structure And Morphology

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Palaeo-oceanography, margin stratigraphy and palaeophysiography of the Tertiary North Atlantic and Norwegian-Greenland seas

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1980.0024 ◽

1980 ◽

Vol 294 (1409) ◽

pp. 177-185 ◽

Cited By ~ 16

Keyword(s):

North Atlantic ◽

Deep Water ◽

Global Climate ◽

Circulation Pattern ◽

The Arctic ◽

Continental Margins ◽

Long Distance ◽

Sea Level Fluctuations ◽

The North ◽

Border Zones

The Tertiary was a period of dramatic changes of the palaeo-oceanography of the world’s oceans in general and of the North Atlantic in particular. These changes were caused by (1) the bathymetric evolution of ocean basins and intrabasin pathways (opening of the Norwegian-Greenland Seas and of the pathway to the Arctic Ocean, interruption of the circumglobal equatorial seaway); (2) the geographical development of the oceans and adjacent marginal basins in the context of rapid and intensive eustatic sea level fluctuations; and (3) the deterioration of the global climate throughout the Tertiary (change from a non-glacial to a glacial world, causing major changes in circulation of the surface and deep water). A biostratigraphy of Tertiary sediments deposited close to the continental margins has been developed by using remains of planktonic floras and faunas. Their presence in these sediments and their usefulness for long distance correlations of margin sediments, depend upon the circulation pattern and hydrographic gradients of the oceanic surface and deep water masses, the climatic regime over the continental border zones, and the probability of their post-depositional preservation.

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Consequences of long-distance swimming and travel over deep-water pack ice for a female polar bear during a year of extreme sea ice retreat

Polar Biology ◽

10.1007/s00300-010-0953-2 ◽

2011 ◽

Vol 34 (7) ◽

pp. 975-984 ◽

Cited By ~ 52

Author(s):

George M. Durner ◽

John P. Whiteman ◽

Henry J. Harlow ◽

Steven C. Amstrup ◽

Eric V. Regehr ◽

...

Keyword(s):

Sea Ice ◽

Deep Water ◽

Polar Bear ◽

Long Distance ◽

Pack Ice ◽

Ice Retreat ◽

Female Polar Bear ◽

Sea Ice Retreat

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Improving the catch efficiency of the West Coast rock lobster, Jasus lalandii

Marine and Freshwater Research ◽

10.1071/mf99063 ◽

2000 ◽

Vol 51 (6) ◽

pp. 613 ◽

Cited By ~ 4

Author(s):

D. Loewenthal ◽

S. Mayfield ◽

G. M. Branch

Keyword(s):

Weight Loss ◽

South African ◽

West Coast ◽

Capture Rate ◽

Catch Rate ◽

Rock Lobster ◽

The South ◽

The West ◽

The Relationship

The South African commercial rock-lobster industry employs an average soak time of 22 h for traps. Experiments were undertaken to test (1) the rate of bait loss with soak time and the effect that protection of the bait has on bait loss, (2) the relationship between catch rate (numbers per trap) and soak time for traps with either protected or unprotected bait, and (3) the effect of two bait types (whole maasbanker and hake heads) on the catch of rock lobsters. There were substantial losses of unprotected bait within 6 h; substantially less weight loss was observed from protected bait even after a 48-h soak time. The numbers of rock lobsters caught in traps with unprotected bait were low relative to the capture rate with protected bait. The highest capture rate occurred after 6 h for unprotected bait and 6–12 h for protected bait. There was no significant effect of bait type (maasbanker v. hake heads) on the number or size of rock lobsters. To optimize catch efficiency, the commercial industry should use protected bait and soak times as short as 6–12 h.

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An evaluation of sleepiness, and sleep on-route in South African long- distance truck drivers

10.51415/10321/1814 ◽

2002 ◽

Author(s):

◽

Michelle Lydia Baker

Keyword(s):

South African ◽

Sleep Duration ◽

Gold Standard ◽

Epworth Sleepiness Scale ◽

Nrem Sleep ◽

Truck Drivers ◽

Long Distance ◽

Validated Questionnaires ◽

Drive Time

The hypothesis that South African long-distance drivers are sleepy at the wheel, and have shortened sleep duration on-route at truck stops arose. The possibility of using gold standard questionnaires for employment in operational settings was also considered. Although many questionnaires, and simulator studies have been used to assess sleepiness in long-distance truck drivers, few studies have monitored drivers on-route, whilst driving. The subjective component involved the use of both the Epworth Sleepiness Scale (ESS) and the Sleep Wake Activity Inventory (SWAI), which are validated . questionnaires developed for assessing sleepiness. Objectively on-route physiological polysomnography (PSG), using specific parameters, was used to record the occurrence of microsleeps and Stage1 NREM sleep, according to international criteria, to monitor drivers, whilst driving, as well as sleep, at a truck stop (N=16). The objective polysomnographic results showed an overall propensity to lapses in consciousness (microsleeps) and progression to sleepiness (Stage1 NREM). A mean total sleepiness score of 19% was calculated across the total drive time, which averaged four hours. This was extrapolated to alcohol levels of BAC 0.05 - 0.1 as described by Williamson & Feyer, (2000).

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