Growth Rates and Age at Maturity for the Plethodontid Salamander Bolitoglossa subpalmata

Copeia ◽  
1982 ◽  
Vol 1982 (2) ◽  
pp. 474 ◽  
Author(s):  
Lynne D. Houck
Keyword(s):  
Growth Rates ◽  
Age At Maturity ◽  
Plethodontid Salamander

The Collapse and Recovery of a Small Whitefish Fishery

1956 ◽  
Vol 13 (1) ◽  
pp. 135-146 ◽  
Author(s):  
Richard B. Miller
Keyword(s):  
Growth Rates ◽  
Eutrophic Lake ◽  
Age At Maturity ◽  
Considerable Effort ◽  
Commercial Catch ◽  
Shallow Eutrophic Lake ◽  
Strong Winds ◽  
Egg Destruction ◽  
Catch Statistics

Pigeon Lake, Alberta, is a shallow eutrophic lake with a sandy basin, gentle contours and an area of 40 square miles. It contains whitefish, pike, yellow walleye, perch, burbot, white suckers and spottail shiners. The whitefish have been commercially exploited for many years and catch statistics are available from 1918.In 1941 a greatly increased catch of whitefish was permitted. Large annual yields continued until 1946; in 1947, in spite of considerable effort, a very small catch was made. Since this collapse fishing was prohibited in two years and light in two years. The lake now contains a normal whitefish population.Samples of the commercial catch during this period showed that the average age of the fish fell from 5.1 to 2.3 years, then, after collapse, increased to 5.7 years. Growth rates increased greatly, then decreased to the original level. Age at maturity decreased from five to two years.Calculations of the number of fish each year-class contributed to the fishery reveal that the collapse of the fishery was not due to overfishing; the weak year-classes which caused the collapse had parent year-classes of normal abundance. It is suggested that egg destruction by strong winds may have caused the weak year-classes.

Life history of a small form of the plethodontid salamander Desmognathus quadramaculatus

2003 ◽  
Vol 24 (1) ◽  
pp. 13-26 ◽  
Author(s):  
Christopher Beachy ◽  
Richard Bruce
Keyword(s):  
Growth Rates ◽  
Frequency Distributions ◽  
Plethodontid Salamander ◽  
Plethodontid Salamanders ◽  
Body Sizes ◽  
Minimum Age ◽  
History Of ◽  
Desmognathus Quadramaculatus ◽  
Gravid Females ◽  
Age At Maturation

AbstractWe sampled Desmognathus quadramaculatus, one of the largest species of plethodontid salamanders in eastern North America, from a population exhibiting extremely small adult body sizes in the Bald Mountains of North Carolina (USA). In order to test the hypothesis that miniaturization in desmognathine salamanders is due to early metamorphosis and maturation, we estimated ages and sizes at metamorphosis and maturation. Analysis of size-frequency distributions suggests that most larvae metamorphose after 24 months, with the remainder metamorphosing after 36. The minimum age of sexually mature individuals in the summer months is estimated to be 4 years in males and 5 years in females; some may mature 1 year earlier. This is earlier than other reliable estimates of age at maturation in D. quadramaculatus, and appears to account for the small size of the species at this locality. Larval and juvenile growth rates are within the range of growth rates of other populations. As in other populations of D. quadramaculatus, males are smaller than females at maturation, but grow to larger sizes. Estimates of clutch sizes based on dissection of gravid females are relatively low. The other species of salamanders in this community do not appear to be miniaturized.

Variability in size and age at maturity in the marine scavengerBuccinanops globulosus(Gastropoda: Nassariidae) from Patagonia

2015 ◽  
Vol 95 (6) ◽  
pp. 1193-1201 ◽  
Author(s):  
María Soledad Avaca ◽  
Pablo Martín ◽  
Maite Narvarte
Keyword(s):  
Growth Rates ◽  
Fishery Management ◽  
Reproductive Effort ◽  
Reaction Norm ◽  
Logistic Function ◽  
Rate Variation ◽  
Female Size ◽  
Age At Maturity ◽  
Management Actions ◽  
Minimum Landing Size

Growth rates and size-age at maturity are life history traits that combine in different ways to achieve maximal fitness. The marine scavengerBuccinanops globulosuswas used as a model to explore the variation on female size-age at maturity and reproductive effort among three populations characterized by different growth rates (slow, moderate and rapid). This species constitutes the target of an artisanal fishery in North Patagonia. Here, a suite of different estimators of size-age at maturity derived from gonad histological analysis and the study of females carrying egg capsules were obtained. Data were modelled using a logistic function and the maturity patterns were compared among populations. We found that female size and age at maturity were variable and site-specific. The fastest-growing population showed the lowest reproductive effort. Slow and rapid-growing females mature at different sizes but at the same age whereas moderate-growing females mature both at a different size and age (intermediate size and at earlier age). Thus, results obtained here are difficult to reconcile with a single reaction norm for a single genotype in the studied populations. Growth rate variation is not enough to explain the patterns described here. The information provided could be used for the establishment of fishery management actions, such as minimum landing size.

Growth and age at maturity of North American tortoises in relation to regional climates

1994 ◽  
Vol 72 (5) ◽  
pp. 918-931 ◽  
Author(s):  
David J. Germano
Keyword(s):  
North American ◽  
Growth Rates ◽  
Environmental Variables ◽  
Mean Annual Precipitation ◽  
Gopherus Agassizii ◽  
Age At Maturity ◽  
Main Determinant ◽  
Gopherus Polyphemus ◽  
Regional Climates ◽  
Richards Growth Model

North American tortoises (Gopherus spp.) are long-lived species that occur in a variety of habitats. I described growth of tortoises using Richards' growth model based on measures of scute annuli. Gopherus flavomarginatus is the largest species and grows the fastest, and Gopherus berlandieri is the smallest species with the slowest growth rates. Gopherus polyphemus and Gopherus agassizii are intermediate in size, with intermediate growth rates. All species grow relatively fast for 18–22 years, after which time growth rates decrease greatly. Estimates of mean age at maturity are 13.3 years for G. berlandieri, 13.9 years for G. flavomarginatus, 14.4 years for G. polyphemus, 13.8 years for Sinaloan G. agassizii, 14.4 years for western Mojave G. agassizii, 15.4 years for eastern Mojave G. agassizii, and 15.7 years for Sonoran G. agassizii. Several measures of growth did not correlate with precipitation among species of Gopherus, although mean yearly growth was negatively correlated with mean annual precipitation in populations of G. agassizii. Also, a matrix of growth variables did not correlate with a matrix of environmental variables. Although other environmental variables should be measured within the ranges of Gopherus spp., preliminary analyses suggest that the environment is not the main determinant of growth rates of North American tortoises.

Life-history variation among populations of Canadian Toads in Alberta, Canada

2005 ◽  
Vol 83 (11) ◽  
pp. 1421-1430 ◽  
Author(s):  
Brian R Eaton ◽  
Cynthia A Paszkowski ◽  
Kent Kristensen ◽  
Michelle Hiltz
Keyword(s):  
Life History ◽  
Growth Rates ◽  
Life History Traits ◽  
Age At Maturity ◽  
Life History Variation ◽  
Size At Age ◽  
Almost All ◽  
Conservation Plans ◽  
Toad Bufo ◽  
Latitudinal Range

Development of appropriate conservation plans relies on life-history information and how life-history traits vary across populations of a species. Such data are lacking for many amphibians, including the Canadian Toad (Bufo hemiophrys Cope, 1886). Here we use skeletochronology to estimate size at age, growth rates, age at maturity, and longevity of toads from nine populations along a latitudinal gradient in Alberta, Canada. Size of individual toads within each year class was highly variable, but age and size (measured as snout-to-urostyle length) were significantly related for almost all populations. The largest individuals were found in the southern-most population, while the smallest toads were found in three populations from the middle of the latitudinal range studied. Growth rates were highest in the southern-most population and lowest at the three populations with relatively small individuals. Maximum age was from 7 to 12 years for the populations sampled. The oldest individuals were found in populations in the middle of the latitudinal range sampled; toads in these populations were smaller than those in all other populations. Age at maturity was 1 year old for males and 2 years old for females in most populations. This study shows that some life-history traits exhibit significant variation between Canadian Toad populations, suggesting that effective conservation of this species will need to include population or area-specific management.

scholarly journals Trends in age-at-maturity and growth parameters of female Northeast Atlantic harp seals, Pagophilus groenlandicus (Erxleben, 1777)

2003 ◽  
Vol 60 (5) ◽  
pp. 1018-1032 ◽  
Author(s):  
Anne Kirstine Frie ◽  
Vladimir A Potelov ◽  
Michael C.S Kingsley ◽  
Tore Haug
Keyword(s):  
Growth Rates ◽  
Barents Sea ◽  
Age Distribution ◽  
Body Growth ◽  
Distribution Area ◽  
Age At Maturity ◽  
Greenland Sea ◽  
The Barents Sea ◽  
Pagophilus Groenlandicus

Abstract We analyzed and compared trends in age-at-maturity and body growth in the Greenland Sea and Barents Sea stocks of harp seals, Pagophilus groenlandicus, from the early 1960s to the early 1990s. Mean and median age at sexual maturity (MAMPM and MdAM) were estimated from Richards curves fit to age-specific proportions mature. No long-term trends were found in the Greenland Sea seals, where a common value of MAMPM (5.6 years) and MdAM (4.8 years) could be fit to samples from 1959 through 1990. There were also no significant changes in length-at-age of molting females between 1964 and 1987. For Barents Sea harp seals, MAMPM increased significantly from 5.4 years in the period 1962–1972 to 6.6 years in 1976–1985 and 8.2 years in 1988–1993, concurrently with a decline in body growth rates. Tests on MdAM also showed an increasing trend, but the grouping of samples was slightly different. Estimates of MAMPM for the Barents Sea stock were similar to previously published back-calculated values of MAM, but simulations showed that this method is sensitive to the age distribution of the sample, thus complicating comparisons between samples with different age structures. The high values of MAMPM and low growth rates in the Barents Sea stock in the late 1980s to early 1990s coincided with severe depletion of important prey species in the Barents Sea, reports of mass invasions of harp seals along the Norwegian coast and indications of reduced body condition. All these are consistent with a hypothesis of reduced per-capita resource levels within the distribution area of Barents Sea harp seals at that time, but no cause-and-effect relationship for the long-term trend in age-at-maturity can be established.

Reduced growth rates of hair in mice following radiation

1966 ◽  
Vol 94 (4) ◽  
pp. 491-498 ◽  
Author(s):  
F. D. Malkinson
Keyword(s):  
Growth Rates

Institutional Theory of Endless Redistribution

2005 ◽  
pp. 4-18 ◽  
Author(s):  
K. Sonin
Keyword(s):  
Property Rights ◽  
Institutional Theory ◽  
Growth Rates ◽  
Rent Seeking ◽  
Economic Institutions ◽  
Wide Spread ◽  
Grass Roots ◽  
Protection Systems ◽  
Private Protection ◽  
The Rich

In unequal societies, the rich may benefit from shaping economic institutions in their favor. This paper analyzes the dynamics of institutional subversion by focusing on public protection of property rights. If this institution functions imperfectly, agents have incentives to invest in private protection of property rights. The ability to maintain private protection systems makes the rich natural opponents of public protection of property rights and precludes grass-roots demand to drive the development of the market-friendly institution. The economy becomes stuck in a bad equilibrium with low growth rates, high inequality of income, and wide-spread rent-seeking. The Russian oligarchs of the 1990s, who controlled large stakes of newly privatized property, provide motivation for this paper.

Waiting for a New Model of Growth: Russia’s Social and Economic Development in 2013

2014 ◽  
pp. 4-32 ◽  
Author(s):  
V. Mau
Keyword(s):  
Economic Policy ◽  
Economic Development ◽  
Economic Performance ◽  
Growth Rates ◽  
Global Crisis ◽  
New Model ◽  
Social And Economic Development ◽  
Economic Risks

The paper deals with Russian social and economic development in 2013 and prospects for the next year or two. The author discusses the logic and trends of the global crisis started in 2008. This is the basis for further analysis of current Russian economic performance with special emphasis on the problem of growth rates deceleration. Special attention is paid to economic risks and priorities of economic policy.

Impacts of Paris Agreement on Russian economy

2018 ◽  
pp. 76-94 ◽  
Author(s):  
I. A. Makarov ◽  
C. Henry ◽  
V. P. Sergey
Keyword(s):  
Climate Change ◽  
Economic Policy ◽  
Growth Rates ◽  
Paris Agreement ◽  
Gdp Growth ◽  
Russian Economy ◽  
Climate Policies

The paper applies multiregional CGE Economic Policy Projection and Analysis (EPPA) model to analyze major risks the Paris Agreement on climate change adopted in 2015 brings to Russia. The authors come to the conclusion that if parties of the Agreement meet their targets that were set for 2030 it may lead to the decrease of average annual GDP growth rates by 0.2-0.3 p. p. Stricter climate policies beyond this year would bring GDP growth rates reduction in2035-2050 by additional 0.5 p. p. If Russia doesn’t ratify Paris Agreement, these losses may increase. In order to mitigate these risks, diversification of Russian economy is required.

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