scholarly journals Growth and survival performance of smooth scallop (Flexopecten glaber Linnaeus, 1758) at different depths in Izmir Bay

2021 ◽  
Author(s):  
Selçuk YİĞİTKURT
Keyword(s):  
Growth And Survival ◽  
Izmir Bay ◽  
Different Depths

Habitat specific trade-offs in growth and survival by hogfish Lachnolaimus maximus in southeast Florida

2021 ◽  
Author(s):  
Ian A Towne ◽  
Paul T Arena ◽  
Angela B Collins ◽  
David W Kerstetter
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Age And Growth ◽  
Fishing Pressure ◽  
Growth And Survival ◽  
Trade Offs ◽  
Eastern Gulf Of Mexico ◽  
Average Maximum ◽  
Reef Tract ◽  
Different Depths

The hogfish Lachnolaimus maximus, an economically important, reef-associated protogynous teleost, has gained additional interest from fisheries managers due to evidence of overfishing in the southeastern United States. This study collected data on age and growth of hogfish in southeast Florida (SEFL), an understudied part of the species’ range. Hogfish (n = 227) were collected from three reef tracts at different depths between January 2016 and August 2017. The average maximum potential length (L∞) was 414 mm overall and showed evidence of Lee’s Phenomenon occurring relative to the eastern Gulf of Mexico, an area of presumed lower fishing pressure, where L∞ was 920 mm. Hogfish growth was also found to vary significantly by reef location in SEFL. Otolith-based aging revealed that SEFL hogfish growth past age 3 significantly decreased as reef depth increased between the three reef tracts [length at age 9 (L9) = 564, 405, 351 mm FL]. By L9, hogfish from the shallowest reef tract (4–6 m) were on average 61% longer and four times the weight of individuals collected from the deepest reef tract (15–25 m). Annual survival also increased with depth (42%, 65%, 73%), with a linear relationship to growth at L9 where R2 = 1.0, indicating there are inherent trade-offs between growth and longevity in hogfish of southeast Florida.

Mounding in the Sub-boreal Spruce Zone of west-central British Columbia: 8-year results

1998 ◽  
Vol 74 (3) ◽  
pp. 421-427 ◽  
Author(s):  
A. Macadam ◽  
L. Bedford
Keyword(s):  
Picea Glauca ◽  
Soil Nutrient ◽  
Height Growth ◽  
Site Preparation ◽  
Slope Position ◽  
Diameter Growth ◽  
Growth And Survival ◽  
Different Depths ◽  
Relative Differences ◽  
Rates Of Growth

Results are presented from two site preparation trials involving mounding on a moist to wet site with a medium soil nutrient regime (5–6/C) located in a lower slope to toe of slope position and on a near-level area upslope from the first site with medium soil moisture and nutrient regimes (4/C). Both trials compared the performance of long-rooted hybrid white spruce (Picea glauca × P. engelmannii [Parry ex Engelm.]) (Sxw) container stock (PSB 323) to that of a standard-sized stock (PSB 313) planted in inverted mounds and untreated spots. The trial on the first site also tested the effectiveness of two mound capping depths and of planting the 313 stock to two different depths in mounded spots. After eight seasons, there were no significant differences between 313s and 323s in terms of height growth or proportions of free growing trees. Although diameter growth was significantly greater among 323s in mounds compared to 313s this relatively small difference is unlikely to justify the higher cost of the larger stock. Height and diameter growth among 313s were 17 and 22% greater, respectively, for trees planted in mounds with 20 cm of capping compared to 12 cm of capping. Deep-planting in mounds consistently resulted in slight increases in height growth and survival relative to planting to the standard depth, though differences were not statistically significant Rates of growth were substantially greater among trees planted in mounds compared with those in untreated spots.The greatest relative differences were noted on the first site where height growth among 313s was 43 to 74% greater in mounded treatments depending on planting depth and capping thickness, with similar improvements in diameter growth. Key words: Site preparation, mounding

Multiple-fracturing and viewing of the same frozen sample at different depths using a low temperature FESEM

1996 ◽  
Vol 54 ◽  
pp. 820-821
Author(s):  
M.V. Parthasarathy ◽  
C. Daugherty
Keyword(s):  
Temperature Field ◽  
Low Temperature ◽  
Field Emission ◽  
Multiple Fracture ◽  
Precise Control ◽  
Cold Stage ◽  
Different Depths ◽  
Transfer Device

The versatility of Low Temperature Field Emission SEM (LTFESEM) for viewing frozen-hydrated biological specimens, and the high resolutions that can be obtained with such instruments have been well documented. Studies done with LTFESEM have been usually limited to the viewing of small organisms, organs, cells, and organelles, or viewing such specimens after fracturing them.We use a Hitachi 4500 FESEM equipped with a recently developed BAL-TEC SCE 020 cryopreparation/transfer device for our LTFESEM studies. The SCE 020 is similar in design to the older SCU 020 except that instead of having a dedicated stage, the SCE 020 has a detachable cold stage that mounts on to the FESEM stage when needed. Since the SCE 020 has a precisely controlled lock manipulator for transferring the specimen table from the cryopreparation chamber to the cold stage in the FESEM, and also has a motor driven microtome for precise control of specimen fracture, we have explored the feasibility of using the LTFESEM for multiple-fracture studies of the same sample.

Daylight in Underground Spaces

2018 ◽  
pp. 156-161
Author(s):  
Alexei K. Solovyov
Keyword(s):  
Light Guide ◽  
Heat Losses ◽  
Internal Environment ◽  
Method Of Calculation ◽  
Natural Lighting ◽  
Different Depths ◽  
The Common ◽  
Different Diameters

Underground spaces in town centres present a big attraction for investors. However, they put special requirements to the internal environment. Those requirements can be fulfilled by means of daylighting. Examples of lighting of underground spaces are discussed. It is shown that the common systems of natural lighting are not always possible to use and cause big heat losses. Hollow light guide pipes allow avoid the shortcomings of common daylight systems. Method of calculation of daylight factors from hollow light guide pipes is shown. The results of calculation of daylight factors under the light guide pipes of different diameters in the different depths are presented.

PREFERENSI PENEMPELAN, PERTUMBUHAN, DAN SINTASAN LARVA TERIPANG PASIR, Holothuria scabra PADA SUBSTRAT LAMUN YANG BERBEDA

2017 ◽  
Vol 11 (3) ◽  
pp. 249
Author(s):  
Lisa Fajar Indriana ◽  
Yuli Afrianti ◽  
Sitti Hilyana ◽  
Muhammad Firdaus Firdaus
Keyword(s):  
Survival Rate ◽  
Economic Value ◽  
Growth And Survival ◽  
Holothuria Scabra ◽  
Enhalus Acoroides ◽  
Randomized Design ◽  
Settlement Substrate ◽  
Cymodocea Rotundata ◽  
Syringodium Isoetifolium ◽  
Cymodocea Serrulata

Teripang pasir, Holothuria scabra merupakan komoditas hasil laut yang bernilai ekonomis tinggi. Penangkapan berlebihan stok di alam mendorong berkembangnya kegiatan budidaya. Penempelan merupakan fase kritis pada larva teripang karena terjadi peralihan sifat planktonis ke bentik yang memerlukan substrat. Penelitian ini bertujuan untuk mengetahui preferensi penempelan, pertumbuhan, dan sintasan larva H. scabra fase penempelan pada substrat lamun yang berbeda. Penelitian menggunakan metode rancangan acak lengkap dengan perlakuan empat jenis daun lamun berbeda dan lima ulangan. Perlakuan terdiri atas Enhalus acoroides (L-1), Syringodium isoetifolium (L-2), Cymodocea serrulata (L-3), dan Cymodocea rotundata (L-4). Jumlah awal larva sebanyak 1.000 individu dan substrat dirangkai dengan luasan yang sama sebesar 12 cm x 17 cm untuk setiap unit penelitian. Hasil penelitian menunjukkan jenis lamun yang digunakan sebagai substrat berpengaruh secara nyata terhadap preferensi penempelan dan sintasan larva teripang pasir, namun tidak berpengaruh terhadap pertumbuhan. E. acoroides menunjukkan hasil terbaik dengan preferensi penempelan 0,26 ind. cm-2 dan sintasan 10,66%; sehingga layak digunakan sebagai substrat penempelan dalam pembenihan teripang pasir, H. scabra.Holothuria scabra larvae on different seagrass substrates. By: Lisa Fajar Indriana, Yuli Afrianti, Sitti Hilyana, and Muhammad FirdausSandfish Holothuria scabra is marine commodities with a high economic value. Overfishing of natural stocks has compelled an interest to begin aquaculture practice. Settlement is a critical phase for the planktonic larvae as they will transform to benthic form in the presence of substrate. This study aims to evaluate the settlement preferences, growth, and survival rate of H. scabra larvae settled on different seagrass leaves. The research was conducted using the Completely randomized design with four different species of seagrass leaves and five replications. The treatments consist of Enhalus acoroides (L-1), Syringodium isoetifolium (L-2), Cymodocea serrulata (L-3), and Cymodocea rotundata (L-4). Initial number of larvae was 1,000 individuals and the substrate was set with same widthof 12 cm x 17 cm for each unit. Results of the experiment indicated that settlement preference and survival rate of H. scabra larvae was significantly affected by seagrass used as substrate while no significantly differences was observed for growth of larvae. E. acoroides showed the best result with 0.26 ind. cm-2 settelement preference and 10.66% survival rate, so that suitable to be used as settlement substrate in H. scabra hatchery.

DEVELOPMENT OF INTEGRATED MONITORING NETWORK FOR MEASURING SALINITY OF SEA WATER

2018 ◽  
pp. 18-26
Author(s):  
Sima Ajdar qizi Askerova
Keyword(s):  
Surface Waters ◽  
Sea Water ◽  
Water Environment ◽  
Monitoring Network ◽  
Monitoring Networks ◽  
The Caspian Sea ◽  
Integrated Monitoring ◽  
Ecological Control ◽  
Different Depths ◽  
Optimal Construction

Monitoring of sea water condition is one of major requirements for carrying out the reliable ecological control of water environment. Monitoring networks contain such elements as sea buoys, beacons, etc. and are designated for measuringvarious hydrophysical parameters, including salinity of sea water. Development of specialized network and a separate buoy system for measuring thesea water salinity at different depths makes it possible to determine major regularities of processes of pollution and self-recovery of the sea waters. The article describes the scientific and methodological basics for development of this specialized network and questions of its optimal construction. It is well-known that at a depth of 30-45 m of the Caspian Sea salinity decreases and then at a depth of 45-60 m salinity is fully recovered. The mentioned changes of salinity at the relatively upper layer of sea waters is of special interest for studying the effect of ocean-going processes on the climate forming in the Caspian area. In terms of informativeness of measurements of surface waters salinity, the most informative is a layer ata 30-60 m depth, where inversion and recovery of salinity take place. It is shown that in most informative subrange of measurements, i. e. at a depth of 30-60 m optimization of regime of measurements complex should be carried out in order to increase the effectiveness of held researches. It is shown that at a depth of 35-50 m choice of the optimum regime of measurements makes it possible to obtain the maximum amount of information.

Consumer Awareness, Consumer Protection, Service Quality and Loyalty: The Case of Long-term Insurance Consumers in Namibia

2019 ◽  
Vol 118 (8) ◽  
pp. 172-189
Author(s):  
Magreth B Tjizumaue ◽  
Krishna Govender
Keyword(s):  
Service Quality ◽  
Consumer Protection ◽  
Structural Equation ◽  
Insurance Industry ◽  
Business Practices ◽  
Consumer Awareness ◽  
Growth And Survival ◽  
Term Insurance ◽  
Protection Legislation

Due to the absence of appropriate Consumer Protection legislation in Namibia, there seems to be a lack of consumer protection, which may result in consumers being exploited. Since the literature reveals that Consumer Awareness, Consumer Protection, Service Quality and Customer Satisfaction influence Customer Loyalty, the aforementioned relationship was explored among consumers of long-term insurance products in Namibia. The researcher embedded the study in the Services Marketing and User’s Satisfaction/Dissatisfaction theory and developed a framework for creating a more aware consumer and thus contribute to the growth and survival of the long-term insurance industry in Namibia.  A survey was conducted using a questionnaire, among a judgmental sample of 407 long-term insurance consumers in Namibia and Structural Equation Modelling was used to analyse (eight) hypothesized relationships among the research constructs alluded to in the title of this study. In summary, it was ascertained that if the customers are fully aware (have sufficient knowledge of the products and their consumer rights), they will feel protected against unfair business practices. Furthermore, if they perceive having received quality services, they are more likely to be satisfied with the service provider and will therefore, remain loyal.

NATURAL FEEDING OF SLUDGE WORMS (Tubifex sp.) WITH DIFFERENT FEEDING RATE ON GROWTH AND SURVIVAL RATE OF CTENOPOMA (Ctenopoma acutirostre) FISH SEEDS

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Muhammad Atilah Setiawan ◽  
Muarif Muarif ◽  
Fia Sri Mumpuni
Keyword(s):  
Survival Rate ◽  
Feeding Rate ◽  
Specific Growth ◽  
Feeding Frequency ◽  
Initial Weight ◽  
Growth And Survival ◽  
Randomized Design ◽  
Absolute Length ◽  
Test Fish ◽  
Completely Randomized Design

The aim of this study was to determine the growth and survival rate of Ctenopoma fish seeds. This study used a completely randomized design with 3 treatments and 3 replications. The treatment in this study was a different feeding rate using natural feed of Tubifex sp  namely A (8%), B (10%), and C (12%) ). The test fish used was Ctenopoma fish seeds with an initial length of 2.40 ± 0.10 cm and an initial weight of 0.32 ± 0.05 g. Fish seeds are cultivated  for 28 days with feeding frequency twice a day. The results of research showed that the use of different feeding rate had an significantly different (P<0.05) on the specific growth  rate and absolute length growth with the best results in the treatment C. The survival rate was not significantly different between treatments (P>0.05). Key Words: Ctenopoma, feeding rate, growth, survival rate 

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