Dynamics of Exploited Whitefish Populations and their Management with Special Reference to the Northwest Territories

1975 ◽  
Vol 32 (3) ◽  
pp. 427-448 ◽  
Author(s):  
M. C. Healey
Keyword(s):  
Growth Rate ◽  
Population Size ◽  
Total Mortality ◽  
High Growth ◽  
Maximum Growth ◽  
High Growth Rate ◽  
Maximum Growth Rate ◽  
Stock Size ◽  
Slow Growth Rate ◽  
Wide Range

Available data on mortality, growth, reproduction, and stock size in exploited and unexploited populations of lake whitefish (Coregonus clupeaformis) are reviewed with a view to understanding the dynamics of exploited populations and improving their management. Natural mortality ranged from about 0.20 to 0.80 in unexploited populations. In exploited populations total mortality was as high as 0.94. Unexploited populations showed a wide range of growth rates. Growth rate increased with increasing exploitation, and growth rate in all heavily exploited populations was similar to the most rapid growth rate shown by unexploited stocks. Heavily exploited whitefish matured at a younger age and possibly also at a smaller size than those which were unexploited. Limited data on stock size suggest that although total population size declines under heavy exploitation, the vulnerable population remains of similar size.It is concluded that whitefish respond to fluctuations in population size through compensatory changes in growth rate, the difference between growth rate in a population and maximum growth rate is a measure of its scope for compensating for increased mortality. Populations with slow growth rate and low mortality should, therefore, have the best fishery potential, while those with high growth rate and high mortality have a low fishery potential. Further, it is possible to judge the fishery potential of a population or its stage of exploitation from relatively simple measurements of mortality, growth, age structure, and maturity.

Development of a High Rate 4H-SiC Epitaxial Growth Technique Achieving Large-Area Uniformity

2008 ◽  
Vol 600-603 ◽  
pp. 111-114 ◽  
Author(s):  
Masahiko Ito ◽  
L. Storasta ◽  
Hidekazu Tsuchida
Keyword(s):  
Growth Rate ◽  
Epitaxial Growth ◽  
Free Exciton ◽  
High Growth ◽  
Maximum Growth ◽  
High Growth Rate ◽  
Maximum Growth Rate ◽  
High Rate ◽  
Intrinsic Defect ◽  
Large Area

A vertical hot-wall type epi-reactor that makes it possible to simultaneously achieve both a high rate of epitaxial growth and large-area uniformity at the same time has been developed. A maximum growth rate of 250 µm/h is achieved at 1650 °C. Thickness uniformity of 1.1 % and doping uniformity of 6.7 % for a 65 mm radius area are achieved while maintaining a high growth rate of 79 µm/h. We also succeeded in growing a 280 µm-thick epilayer with excellent surface morphology and long carrier lifetime of ~1 µs on average. The LTPL spectrum shows free exciton peaks as dominant, and few impurity-related or intrinsic defect related peaks are observed. The DLTS measurement for an epilayer grown at 80 µm/h shows low trap concentrations of 1.2×1012 cm-3 for Z1/2 center and 6.3×1011 cm-3 for EH6/7 center, respectively.

scholarly journals Influence of types of constitution on meat productivity bullets of Simmental breed

2021 ◽  
Vol 273 ◽  
pp. 02024
Author(s):  
Anatoly Shevkhuzhev ◽  
Vladimir Pogodaev ◽  
Dagir Smakuev
Keyword(s):  
Growth Rate ◽  
Beef Cattle ◽  
Meat Products ◽  
Live Weight ◽  
High Growth ◽  
Maximum Growth ◽  
High Growth Rate ◽  
Maximum Growth Rate ◽  
Cattle Breeding ◽  
Meat Productivity

The aim of the research was to establish quantitative and qualitative indicators of meat productivity of Simmental bull calves of various constitutional types when raised using the technology of beef cattle breeding. The maximum growth rate and the highest yield of meat products were obtained from Simmental bulls of the meat and dairy type when they were raised and fed according to the technology of beef cattle breeding. Receiving from the mothers for 205 days of the sucking period more fatty milk, they gave 1250 g of gain per day and reached 289.7 kg of live weight by the cut. Having retained a high growth rate in the future, they at the final fattening gave 1321 g of gain per day and at 20 months the live weight was 659.3 kg. The superiority of Simmentals over analogues was natural by 3.4–13.3% by weight of the steamed carcass, by 0.4–1.8% in slaughter yield, by 1.4–11.1 kg in terms of the amount of pulp in the carcass and pulp per bones by 0.1–0.3 kg, protein in meat by 0.12; 1.19; 2.59 kg and the amount of energy in the pulp by 0.14; 0.44; 1.75 MJ. Simmental bulls of the meat and dairy type also have a high ability to transform protein and feed energy into protein and energy from the pulp of the carcass.

The Annual Growth-Rate Cycle in Brown Trout (Salmo Trutta Linn.) and Its Cause

1961 ◽  
Vol 38 (3) ◽  
pp. 595-604
Author(s):  
D. R. SWIFT
Keyword(s):  
Growth Rate ◽  
Brown Trout ◽  
Salmo Trutta ◽  
High Growth ◽  
Maximum Growth ◽  
Field Work ◽  
High Growth Rate ◽  
Maximum Growth Rate ◽  
Annual Growth ◽  
Annual Growth Rate

1. A regular annual growth-rate cycle is demonstrated in wild and hatchery yearling brown trout; the fish have a high growth rate in the spring and autumn and a low growth rate during the summer and winter of each year. 2. Experimental work with constant-environment aquaria, together with the results of the field work, indicate that the water temperature is the main external environmental factor influencing the growth rate. Maximum growth rate is achieved at 12° C. 3. The reason for the fall in growth rate above 12° C. is discussed and it is suggested that inadequacy of the respiratory system of the fish is the prime cause.

Development of High Growth Rate SiC Epi-Reactor with Controlled Thermal Gradient

2007 ◽  
Vol 556-557 ◽  
pp. 81-84
Author(s):  
Masahiko Ito ◽  
Hidekazu Tsuchida ◽  
Isaho Kamata ◽  
L. Storasta
Keyword(s):  
Growth Rate ◽  
Thermal Gradient ◽  
Gas Flow ◽  
Flow Behavior ◽  
High Growth ◽  
Maximum Growth ◽  
High Growth Rate ◽  
Maximum Growth Rate ◽  
Simulation Results ◽  
Growth Experiments

A vertical hot-wall type reactor, with a unique structure designed for controlling both gas flow behavior and thermal gradient (T/mm) on the susceptor surface, was developed. The simulation results indicate that depending on the height of the epitaxy room (h), the T/mm can be changed from a negative to a positive value. Preliminary epitaxial growth experiments resulted in a maximum growth rate of 51 μm/h, 4-inch area uniformity of σ/mean=1.7% for growth rate and σ/mean=21.5 % for doping concentration, and Z1/2 trap concentration of 9×1012 cm-3 at a growth rate of 43 μm/h.

scholarly journals 335EFFECT OF PATERNAL LINE OF DONOR ON SUPEROVULATORY RESPONSE AND EMBRYO QUALITY IN JAPANESE BLACK HEIFERS

2004 ◽  
Vol 16 (2) ◽  
pp. 287 ◽  
Author(s):  
M. Asada ◽  
Y. Hashiyada ◽  
K. Konishi
Keyword(s):  
Growth Rate ◽  
Embryo Quality ◽  
High Growth ◽  
High Growth Rate ◽  
Intermediate Type ◽  
Japanese Black Cattle ◽  
Gnrh Analog ◽  
Slow Growth Rate ◽  
Paternal Line ◽  
Meat Type

The objective of this study was to investigate the effect of paternal line of donor on superovulatory response and embryo quality in Japanese Black cattle. Japanese Black cattle have paternal lines that can be classified into the following, according to meat quality and the growth rate: ‘high marbling meat type’, ‘high growth rate type’ and ‘high marbling meat and high growth rate (intermediate type)’. We hypothesized that paternal line of donor may affect superovulatory response. One hundred and forty superstimulations were performed on 56 Japanese Black heifers, and data on superovulatory response and embryo collection were analyzed. Japanese Black donors used in this study were from the following 4 paternal lines: Kedaka (large-framed with high growth rate;; n=9, 30 times), Fujiyoshi (intermediate type;; n=22, 47 times), Shigekane (high marbling meat type;; n=13, 40 times), and Tajiri (high marbling meat type and small-frame with slow growth rate;; n=12, 23 times). Donors were synchronized using a CIDR-B (EAZI-BREED, InterAg, NZ) for 8 to 12 days, and 500μg PGF analog (Resipron-C; Teikoku Zouki, Japan or Clopromate-C; Sumitomo, Japan) administered at CIDR removal. Superstimulation was initiated on Day 10 (Day 0=day of estrus) of the synchronized cycle;; FSH (Antrin R10;; Denka, Japan) was administered twice daily for 4 days with decreasing doses for a total of 28 Armour units FSH. PGF analog was administered in the morning on the last day of FSH treatment. Donors were given 50 or 100μg GnRH analog (Sporunen, Denka, or Conceral, Takeda Schering prau, Japan) at the time of estrus detection, and were inseminated 12h after the onset of estrus. Embryos were recovered on Day 7 after AI. The numbers of CL and follicles were recorded with transrectal ultrasonography immediately after embryo recovery. Embryos were classified according to the IETS Manual. Data were analyzed by Kruskal-Wallis test combined with Scheffe’s multiple comparison test. There were no significant differences in CL numbers among paternal lines: Kedaka (9.5±4.2), Fujiyoshi (8.5±5.1), Shigekane (7.8±5.0) and Tajiri (8.6±4.1). Mean number of recovered ova/embryos per donor was significantly (P<0.05) higher in the Kedaka line (8.4±5.1) than in the Fujiyoshi (4.9±4.1) and Shigekane (5.5±7.0) lines. The percentages of viable embryos was greater (P<0.05) in the Fujiyoshi (73.7%) and Shigekane lines (62.8%) than in the Tajiri line (50.9%), whereas the percentage of unfertilized oocytes was significantly (P<0.05) higher in the Tajiri line (41.5%) than in the Fujiyoshi (17.5%) or Shigekane (26.1%) lines. The percentages of freezeable and transferable embryos were not significantly different among paternal lines. Data suggest that the paternal line had an effect on the superstimulatory response in Japanese Black heifers, and especially the number and percentage of viable embryos per donor.

The assessment of seasonal yield using some Stylosanthes guyanensis accessions in humid tropical and sub-tropical environments

1977 ◽  
Vol 17 (86) ◽  
pp. 425 ◽  
Author(s):  
LA Edye ◽  
WT Williams ◽  
RL Burt ◽  
B Grof ◽  
SL Stillman ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Growth ◽  
Growth Period ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Growth Patterns ◽  
Seasonal Growth ◽  
Seasonally Dry ◽  
Tropical Environments ◽  
Dry Tropics

The seasonal growth patterns of some S. guyanensis accessions were compared in three humid environments at South Johnstone (extended rainfall tropics), 'Heathlands' (seasonally dry tropics) and Cooroy (humid sub-tropics). The accessions were selected mainly for their productivity in previously described small mown sward experiments over three years at each site. Previous methods of presenting seasonal growth patterns are reviewed, and a new, simpler method of presentation is defined. Growth was highly seasonal at all sites. There was no growth during July to November at 'Heathlands' and Cooroy due to moisture and temperature limitations respectively. At South Johnstone growth was continuous but depressed in August and December with limitations due to both soil moisture and temperature: the maximum growth rate was 22 times the minimum growth rate. The accessions differed markedly in their growth patterns at each site. In general, the yield differences between accessions were greater at the beginning and end of the growing season than during the peak growth period. The highest yielding accessions at each site had high growth rates spread over a long period. The yield distribution and persistence of Q8231 and 46589C seemed superior to existing cultivars in tropical and sub-tropical environments respectively

Phosphate response of Trifolium uniflorum compared with T. repens and some T. repens×T. uniflorum hybrids

2015 ◽  
Vol 66 (8) ◽  
pp. 857 ◽  
Author(s):  
S. N. Nichols ◽  
J. R. Crush
Keyword(s):  
Growth Rate ◽  
White Clover ◽  
Leaf Tissue ◽  
High Growth ◽  
High Growth Rate ◽  
Interspecific Hybridisation ◽  
Growth Responses ◽  
Slow Growth Rate ◽  
Soil P ◽  
Hill Country

Introgression of genes from Trifolium uniflorum L. into T. repens L. (white clover) is being investigated as a method to improve phosphorus (P) use efficiency in white clover; however, little is known about the edaphic adaptations or P physiology of T. uniflorum. Growth responses to added P of T. uniflorum, T. repens and some T. repens × T. uniflorum hybrids were determined in a glasshouse experiment in pots of soil. Trifolium uniflorum showed traits consistent with adaptation to low-P soils: slow growth rate, small leaves, relatively high leaf-tissue P concentrations, and sequestration of P in its roots when soil P levels were increased. The response of Kopu II, one of the hybrid backcross parents, was quite different; it showed high growth rate, large leaves, much lower leaf P concentrations, and a large decrease in root : shoot P allocation as soil P increased. Tahora, the other backcross parent, exhibited several characteristics that were intermediate between Kopu II and T. uniflorum, probably reflecting its breeding origins from New Zealand hill-country ecotypes. This study confirms the potential for interspecific hybridisation with T. uniflorum to increase the tolerance of white clover to low soil P levels, through incorporation of traits related to edaphic adaptations. Variation among the hybrid families in their response to changing soil P confirmed previously published conclusions about the need to screen widely in hybrid material.

scholarly journals Effects of index selection on the performance and carcass composition of sheep given foods of different protein concentrationsad libitum

2004 ◽  
Vol 78 (2) ◽  
pp. 203-212 ◽  
Author(s):  
R. M. Lewis ◽  
G. C. Emmans ◽  
G. Simm
Keyword(s):  
Growth Rate ◽  
Dietary Protein ◽  
Protein Concentration ◽  
Live Weight ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Carcass Composition ◽  
Control Line ◽  
Wide Range ◽  
Males And Females

AbstractSheep of a line selected on an index to increase carcass lean content at 150 days of age (selected (S); no. = 90), and an unselected control line (control (C); no. = 90), were given ad libitum foods of three different protein concentrations (192, 141 and 120 g/kg dry matter). Growth was measured from about 21 to 114 kg live weight. The carcasses of each line were analysed for lean, fat and bone at three widely varying weights in both males and females. Level of protein did not affect the extent to which S was superior to C in the content of fat (0.86 as much) or lean (1.08 as much) in the carcass. The fat concentration of the carcass increased, and the lean concentration decreased, as dietary protein concentration was reduced (P < 0.01). On the highest level of protein used, the S line grew 1.17 times as fast and was 1.10 times as efficient compared with C. The extent to which growth rate in S exceeded that in C was greater on the highest level of protein used (92.3 g/day) than on the two lower protein diets (26.4 g/day). The difference of 65.9 (s.e. 18.4) g/day was significant (P < 0.01). On the diet of highest protein concentration, growth was well described by a Gompertz function. The S line had an estimated maximum growth rate 1.25 times that of the C when averaged across males and females. A Spillman function was used to describe weight in terms of cumulative intake. It worked well for all three levels of dietary protein concentration. S sheep performed better than unselected sheep on foods differing in protein concentration and over a wide range of live weights, suggesting benefits are likely within the diverse farming environments found in practice.

Developing Technologies of SiC Gas Source Growth Method

2016 ◽  
Vol 858 ◽  
pp. 23-28 ◽  
Author(s):  
Jun Kojima ◽  
Yuichiro Tokuda ◽  
Emi Makino ◽  
Naohiro Sugiyama ◽  
Norihiro Hoshino ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mass Production ◽  
High Speed ◽  
High Growth ◽  
Maximum Growth ◽  
High Growth Rate ◽  
Average Growth ◽  
Gas Source ◽  
Growth Method ◽  
Production Technologies

In order to diffuse the use of SiC, mass-production technologies of SiC wafers are needed. It is easy to be understood that high-speed and long-sized growth technologies are connected directly with mass-production technologies. The gas source growth method such as HT-CVD has the possibilities and the potential of the high-speed and long-sized growth. In this article, it was clarified that the high growth rate were achieved by the control of the source gas partial pressures and by the gas boundary layers. The average growth rate was 1mm/h on the f4 inch-diameter crystal, and the maximum growth rate reached 3.6 mm/h on the 12.5x25 mm tetragon by the above gas control. The crystal qualities of the gas source methods were also evaluated the equivalent level in comparison with the sublimation method. Concerning the 1mm/h-growth f3 inch crystal, the densities of TSDs were kept in the 102 cm-2 levels from the seed to the upper-side of the ingot. Moreover, the ingot size increased year by year and a f4 inch x 43 mm sized ingot has been developed.

Influence of phosphorus on growth and biomass distribution of Alaskan taiga tree seedlings

1983 ◽  
Vol 13 (6) ◽  
pp. 1092-1098 ◽  
Author(s):  
F. Stuart Chapin III ◽  
Peter R. Tryon ◽  
Keith Van Cleve
Keyword(s):  
Growth Rate ◽  
Black Spruce ◽  
White Spruce ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Sand Culture ◽  
Tree Seedlings ◽  
Slow Growth Rate ◽  
Phosphate Supply ◽  
High Phosphate

Seedlings of six Alaskan taiga tree species and one tall shrub were grown in sand at three phosphate levels. There was a positive correlation between the growth rate of a species at the high-phosphate level in sand culture and its productivity in the natural environment. Poplar (Populusbalsamifera L.), which had highest growth rate under high phosphate, was most sensitive to reduction in phosphate supply, followed by birch (Betulapapyrifera (Reg.) Fern, and Raup) and aspen (Populustremuloides Michx.), whereas growth of conifers (larch (Larixlaricina (Du Roi) K. Koch), white spruce (Piceaglauca (Moench) Voss), and black spruce (P. mariana (Mill.) B.S.P.)) from late successional sites was slow and unaffected by phosphate supply. Similarly, when birch and white spruce seedlings were transplanted into natural forest stands, the maximum growth rate of birch was greater than that of white spruce, but birch growth was curtailed more by unfavorable conditions than was that of white spruce. We conclude that a slow growth rate reduces nutrient requirement and therefore minimizes nutrient stress on infertile sites, whereas a rapid growth enables nutrient-demanding species to dominate fertile sites.

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