Late-Pleistocene and Holocene Remains of Hysterocarpus traski (Tule Perch) from Clear Lake, California, and Inferred Holocene Temperature Fluctuations

1977 ◽  
Vol 7 (1) ◽  
pp. 133-143 ◽  
Author(s):  
Richard W. Casteel ◽  
David P. Adam ◽  
John D. Sims
Keyword(s):  
Growth Rates ◽  
General Pattern ◽  
Western United States ◽  
Fish Length ◽  
Northern Coast ◽  
Tree Line ◽  
Coast Range ◽  
Clear Lake ◽  
Measuring Scale ◽  
Early And Middle Holocene

The remains of scales of Hysterocarpus traski Gibbons (Tule perch) were found throughout a 27.44-m core from Clear Lake. Most scales occurred between the mud surface and deposits approximately 11,000 years old. Changes in growth rates of the animals were examined by measuring scale annuli and applying an empirically established regression of fish length on scale radius. The data indicate a pattern of accelerating growth rates, reaching a peak between ⋍4000 and 2800 BP. After ⋍2800 BP, growth rates decline markedly. Because the growth rates of these animals are essentially dependent on temperature, the changes observed in the patterns of growth probably reflect changes in climate in the northern Coast Range. The general pattern of inferred temperature increase during the early and middle Holocene, ending between ⋍4000 and 2800 BP, is consistent with evidence from tree-line studies and palynology indicating higher temperatures in parts of the western United States during this period.

Age and growth of Murray Cod, Maccullochella peelii (Perciformes: Percichthyidae), in the Lower Murray-Darling Basin, Australia, from thin-sectioned Otoliths

1992 ◽  
Vol 43 (5) ◽  
pp. 983 ◽  
Author(s):  
JR Anderson ◽  
AK Morison ◽  
DJ Ray
Keyword(s):  
Growth Rates ◽  
Growth Parameters ◽  
Age And Growth ◽  
Average Error ◽  
Fish Length ◽  
Exponential Relationship ◽  
Thin Sections ◽  
False Rings ◽  
Murray Darling Basin ◽  
Murray Cod

Transverse thin sections (0.5 mm thick) of sagittal otoliths from 290 Murray cod up to 1400 mm in total length and 47.3 kg in weight were used to establish the age and growth of cod in the lower Murray-Darling Basin, including comparisons of recent (1986-91) and past (1949-51) growth rates and growth in different waters. The maximum estimated age was 48 years. Quantitative and qualitative analysis of the seasonal changes in otolith marginal increments showed that annuli in fish of all ages were laid down each spring, and 1 October was assigned as the birthday. The thin-sectioning method was validated by comparing age estimates for 55 Murray cod from Lake Charlegrark (age 0-21 years), which had been validated by using burnt and polished half-otoliths. The new method had an accuracy of 96.4% and it offers major advantages in ease of preparation, reading, and batch-handling of large numbers of otoliths. The precision of the method, estimated as an average error for four readers, was 5.4% (3.0% after ignoring discrepancies in relation to annuli on otolith edges). There was a linear relationship between otolith weight and fish age and an exponential relationship between otolith weight and fish length. Both otolith length and otolith width reached an asymptote at about 15 years, when fish length also approached its maximum. However, otolith thickness continued to increase throughout the life of the fish and, after about 15 years, contributed most to the increase in otolith weight. This confirmed that otoliths continued to grow in thickness and that annuli were laid down throughout life, and that cod could be aged reliably to the maximum age. The annulus pattern is very clear and distinct, and the reading techniques are fully described, including recognition of 'larval' and 'false' rings. Various differences were found in the growth rates, and the length-weight relationships for males and females, for cod caught in 1986-91 and those caught in 1949-51, and various subpopulations are discussed. The von Bertalanffy growth parameters (all individuals combined) were estimated at L∞ = 1202 mm, k=0.108 and t0= -0.832. The availability of a reliable ageing method provides the first opportunity to determine year of birth and thus to examine the age structure of populations and to effectively manage cod populations that have declined in abundance.

An unusual stone circle, Chilcotin Range, British Columbia, Canada

2011 ◽  
Vol 48 (12) ◽  
pp. 1523-1529
Author(s):  
Michael Czajkowski ◽  
Andrew V. Okulitch
Keyword(s):  
British Columbia ◽  
Circular Ring ◽  
Tree Line ◽  
Coast Range ◽  
Rock Unit ◽  
Freeze Thaw ◽  
Anthropogenic Origin ◽  
Protective Cover ◽  
Rubble Pile

A unique circular feature of uncertain origin lies above the tree line on the eastern flanks of the Coast Range of British Columbia, Canada. It is composed of white, fractured, angular cobbles to boulders predominantly under 1 m across, arrayed in a slightly flattened circle nearly 50 m in diameter with the ring mostly about 4 m in width. The felsic granitoid lithology of the circle is unlike any in the immediate region, and no clasts of this composition occur within the circle. The debris rests on soliflucted soil containing rounded pebbles to cobbles of granodiorite that forms the regional lithology. The age of the circle is deglacial with post-glacial modification. Given the absence of similar lithologic units in the region and no obvious symbolic purpose for such a feature, an anthropogenic origin for the circle is improbable. Mechanisms for transporting the foreign rock unit to its final location, distributing fragments into a circle, and preserving it include flow of alpine and fringing continental ice masses, deglaciation, freeze–thaw cycles, and post-glacial solifluction and erosion. One large slab was either entrained within or fell onto a flowing glacier from some unknown outcrop at least 2 km from the site of the circle. During deglaciation, the insulating cap preserved the ice beneath it forming an isolated stagnant mass of ice. Freeze–thaw cycles likely affected the slab when it was on the surface of the ice, but it remained coherent, otherwise glacial flow or meltwater streams might have scattered loose clasts. Once the ice became stagnant, continued freeze–thaw cycles eventually created a rubble pile, which slid off the presumably symmetrical mass of ice to become arranged in a roughly circular ring. Having lost its protective cover, the ice melted and subsequent solifluction slightly modified the ring.

Growth rates of four Hawaiian deep slope fishes: a comparison of methods for estimating age and growth from otolith microincrement widths

1997 ◽  
Vol 54 (1) ◽  
pp. 126-136 ◽  
Author(s):  
H A Williams ◽  
M K Lowe
Keyword(s):  
Growth Rates ◽  
Growth Curves ◽  
Age And Growth ◽  
Interval Length ◽  
Fish Length ◽  
Comparison Of Methods ◽  
Increment Width ◽  
Daily Increment ◽  
Minimum Number ◽  
Age Estimates

Two methods were used to estimate the age and growth of four Hawaiian deep slope fishes. Otolith daily increment width estimates from radial sections of sagittal otoliths were integrated over the otolith radius to approximate age by (i) dividing interval length (micrometres) by mean increment width (micrometres per day) and summing this quotient for consecutive 500- µm radial intervals (S. Ralston and H.A. Williams. 1989. Fish. Bull. 87: 1-16) and (ii) fitting increment width (y) versus otolith radius (x) to a Gompertz rate curve and calculating the inverse integral of this curve (M.K. Smith and E. Kostlan. 1991. Fish. Bull. 89: 461-472). The methods also differ in the way the age-length key is generated. Ralston and Williams' method uses integrated age versus a regression-based estimate of fish length at 500- µm otolith radial intervals; Smith and Kostlan's method uses estimated age versus actual fish length. Neither method of integration produced significantly different age estimates; however, the use of regression-based fish length estimates instead of sampled fish lengths resulted in significant differences between estimated growth curves. The minimum number of daily increment width estimates required as a function of otolith radius was calculated, on the basis of observed microincrement width variation.

Changing Labour Market Indicators and the Rate of Economic Growth in Latin America during the 2000s

2017 ◽  
Author(s):  
Guillermo Cruces ◽  
Gary S. Fields ◽  
David Jaume ◽  
Mariana Viollaz
Keyword(s):  
Labour Market ◽  
Latin American ◽  
Growth Rates ◽  
General Pattern ◽  
Gdp Per Capita ◽  
International Crisis ◽  
Poverty And Inequality ◽  
Latin American Region ◽  
Per Capita ◽  
Latin American Countries

The Latin American region exhibited an increase in gross domestic product per capita during the 2000s, an improvement in all employment and earnings indicators, and poverty and inequality reductions. On a country-by-country basis, all Latin American countries exhibited positive GDP per capita growth rates during the 2000s. Most countries experienced substantial improvements in labour market conditions over the period, Honduras being the only exception to this general pattern. Finally, the growth rates of most countries in the region were negatively affected by the international crisis of 2008, which also affected several labour market indicators in the worsening direction. Most labour market indicators had fully or partially recovered by 2012–13.

Crustal refraction profile, Oregon coast range

1966 ◽  
Vol 56 (6) ◽  
pp. 1357-1362
Author(s):  
Joseph W. Berg ◽  
Lynn Trembly ◽  
David A. Emilia ◽  
Jeremy R. Hutt ◽  
John M. King ◽  
...  
Keyword(s):  
Velocity Gradient ◽  
Seismic Waves ◽  
Northern Coast ◽  
Coast Range ◽  
Time Data ◽  
Oregon Coast Range ◽  
Oregon Coast ◽  
Travel Time Data ◽  
Quarry Blast ◽  
Distance Data

Abstract Seven temporary and three permanent seismograph stations recorded seismic waves to a distance of about 270 km from a 110,000 pound quarry blast detonated near Depoe Bay, Oregon. The recording stations were in a north-south line along the northern coast range of Western Oregon and Washington. The travel-time data indicate an apparent shallow crustal thickness (about 16 km) for this region. The time versus distance data were not continuous beyond 130 km from the source which may have resulted from any combination of the following causes: (1) insufficient source energy; (2) lateral geological variations; and/or (3) a subcrustal negative velocity gradient.

Validation of the use of thin-sectioned Otoliths for determining the age and growth of Golden Perch, Macquaria ambigua (Perciformes: Percichthyidae), in the Lower Murray-Darling Basin, Australia

1992 ◽  
Vol 43 (5) ◽  
pp. 1103 ◽  
Author(s):  
JR Anderson ◽  
AK Morison ◽  
DJ Ray
Keyword(s):  
Growth Rates ◽  
Total Weight ◽  
Birth Date ◽  
Fish Length ◽  
Thin Sections ◽  
Continuous Growth ◽  
Total Length ◽  
Murray Darling Basin ◽  
The Mean ◽  
Age Estimates

Golden perch, Macquaria ambigua, from the Murray-Darling Basin were aged by using transverse thin sections of their sagittal otoliths. Samples from 889 fish were obtained from riverine and lacustrine habitats and from wild and stocked populations. Error in the precision of age estimates (calculated as the mean percentage error of the independent age estimates of four readers) was 5.6% (3.9% after allowing for discrepancies in relation to the annual mark on the edge of the otolith). Validation was accomplished by using a combination of analysis of the progression of modes in length-frequency distributions, qualitative and quantitative marginal-increment analysis, and analysis of age estimates of fish from populations with a known stocking history. The technique was validated for fish up to 8 years of age (455-545 mm total length, 1695-3988 g total weight), and the greatest recorded age was 16 years (530-600 mm total length, 2607-4050 g total weight). Annual marks become visible in otolith sections in most fish of all ages in October, and 1 October was designated as the birth date. A description of our method of reading sections of golden perch otoliths, including recognition of false annual marks, is given. Otolith length, width and thickness increased linearly with fish length and with loglo(fish age), whereas otolith weight increased linearly with fish age and exponentially with fish length. The continuous growth of the otoliths and the consistency in the appearance of annual marks support the accuracy of estimates up to the maximum recorded age. The mean length-at-age and the parameters of the length-weight relationship were estimated. The von Bertalanffy growth parameters were also estimated (L∞ =507 mm, to=0.420 years, K=0.454). No significant differences were found in growth rates or length-weight relationships between males and females. However, growth (particularly in weight) was highly variable among sites and years, and slow-growing 5-year-olds may be shorter than fastgrowing 1-year-olds. Ages were estimated for a sample of 86 golden perch caught between 1949 and 1951 but a comparison of growth rates between these and more recent collections was inconclusive.

scholarly journals Analysis of new particle formation (NPF) events at nearby rural, urban background and urban roadside sites

2019 ◽  
Vol 19 (8) ◽  
pp. 5679-5694 ◽  
Author(s):  
Dimitrios Bousiotis ◽  
Manuel Dall'Osto ◽  
David C. S. Beddows ◽  
Francis D. Pope ◽  
Roy M. Harrison
Keyword(s):  
Urban Environment ◽  
Growth Rates ◽  
General Pattern ◽  
Particle Growth ◽  
Particle Formation ◽  
Atmospheric Conditions ◽  
New Particle Formation ◽  
Urban Background ◽  
Air Masses ◽  
Condensation Sink

Abstract. New particle formation (NPF) events have different patterns of development depending on the conditions of the area in which they occur. In this study, particle size distributions in the range of 16.6–604 nm (7 years of data) were analysed and NPF events occurring at three sites of differing characteristics – rural Harwell (HAR), urban background North Kensington (NK), urban roadside Marylebone Road (MR), London, UK – were extracted and studied. The different atmospheric conditions in each study area not only have an effect on the frequency of the events, but also affect their development. The frequency of NPF events is similar at the rural and urban background locations (about 7 % of days), with a high proportion of events occurring at both sites on the same day (45 %). The frequency of NPF events at the urban roadside site is slightly less (6 % of days), and higher particle growth rates (average 5.5 nm h−1 at MR compared to 3.4 and 4.2 nm h−1 at HAR and NK respectively) must result from rapid gas-to-particle conversion of traffic-generated pollutants. A general pattern is found in which the condensation sink increases with the degree of pollution of the site, but this is counteracted by increased particle growth rates at the more polluted location. A key finding of this study is that the role of the urban environment leads to an increment of 20 % in N16–20 nm in the urban background compared to that of the rural area in NPF events occurring at both sites. The relationship of the origin of incoming air masses is also considered and an association of regional events with cleaner air masses is found. Due to lower availability of condensable species, NPF events that are associated with cleaner atmospheric conditions have lower growth rates of the newly formed particles. The decisive effect of the condensation sink in the development of NPF events and the survivability of the newly formed particles is underlined, and influences the overall contribution of NPF events to the number of ultrafine particles in an area. The other key factor identified by this study is the important role that pollution, both from traffic and other sources in the urban environment (such as heating or cooking), plays in new particle formation events.

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