Angolan highlands peatlands: Extent, age and growth dynamics

AbstractThe growth dynamics of Phymaturus patagonicus, a diurnal, herbivorous and viviparous lizard from the Argentinean Patagonian steppe, was studied using eight juveniles (two born in the laboratory), 11 adult females and eight adult males. Histological cross sections of femoral bones were analysed to determine if individuals show osseous growth marks and if these marks provide useful age estimates. Individual ages were assessed after estimating the reabsorbed rings in relation to snout-vent length. There was a strong relationship between body length and estimated age, modelled by a sigmoidal curve. Sexual maturity was found to be reached at seven years in females and nine in males and the maximum life span was estimated to be 16 years. No difference in body length was observed between the same-age females and males. We postulate that severe environments such as the north Patagonian steppe play a significant role in the selection of not only modes of reproduction but also delayed maturity and prolonged reproductive cycles, a combination that results in low fecundity.

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Age and growth dynamics of Tyrannosaurus rex

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2004.2829 ◽

2004 ◽

Vol 271 (1551) ◽

pp. 1875-1880 ◽

Cited By ~ 97

Author(s):

John R. Horner ◽

Kevin Padian

Keyword(s):

Growth Dynamics ◽

Age And Growth

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Age and growth dynamics of spiny dogfish, Squalus acanthias, in the Adriatic Sea (Eastern Mediterranean Sea)

Marine and Freshwater Research ◽

10.1071/mf14116 ◽

2016 ◽

Vol 67 (3) ◽

pp. 357 ◽

Cited By ~ 3

Author(s):

Romana Gračan ◽

Scott A. Heppell ◽

Gordana Lacković ◽

Bojan Lazar

Keyword(s):

Adriatic Sea ◽

Growth Models ◽

Eastern Mediterranean ◽

Growth Dynamics ◽

Fishing Effort ◽

Age And Growth ◽

Percentage Error ◽

Parameter Estimates ◽

Spiny Dogfish ◽

Average Percentage

This research provides the first information on age and growth estimates for the endangered Mediterranean subpopulation of spiny dogfish, a commercially exploited shark, highly sensitive to overexploitation. We collected samples from 206 specimens caught by commercial bottom trawls in the Adriatic Sea, and utilising three ageing protocols achieved good agreement between the readings (average percentage error=1.65%). Four growth models were fitted to length-at-age and weight-at-age data, for each sex separately. The Gompertz growth model produced the statistically best fit resulting in the following parameters: k values for males and females were 0.09 and 0.04 year–1, size-at-birth ranged from 22.9 to 24.1-cm total length, with a theoretical asymptotic length of 103.3cm for males and 173.3cm for females. The age at 50% maturity was 10.5 years for males and 20.1 years for females. The maximum age was estimated at 23 years for males and 36 years for females, with natural mortality estimates of 0.12 for males and 0.07 for females. As a result of reported demographic parameter estimates, high fishing effort and particularly low resilience of the species to exploitation, it is important to produce proper species-specific management strategy for the spiny dogfish in the region.

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Age and growth, reproductive biology, and histology in Atlantic needlefish (Strongylura marina) in a coastal freshwater lake

Marine and Freshwater Research ◽

10.1071/mf16211 ◽

2017 ◽

Vol 68 (7) ◽

pp. 1325 ◽

Cited By ~ 1

Author(s):

Mary E. Egbert ◽

Roger A. Rulifson

Keyword(s):

Gonadosomatic Index ◽

Atlantic Coast ◽

Length Distribution ◽

Growth Dynamics ◽

Age And Growth ◽

Fish Length ◽

Water Control ◽

Coastal Lake ◽

Western Atlantic ◽

Coastal Watershed

The Atlantic needlefish (Strongylura marina) is a coastal epipelagic species inhabiting shallow coastal waters along the western Atlantic coast from Maine to Brazil. Little has been published about the species due to lack of commercial or sport value. A population exists in Lake Mattamuskeet, a coastal lake connected to Pamlico Sound (NC, USA) via four man-made canals, and fish access is controlled by water-control structures. Herein we describe the life history and age and growth dynamics of the species in the lake. Based on anecdotal and state reports, we believe this species may exhibit anadromy. Sampling was from March to May 1997 and 1998, and from March to October 2001. We also collected from another coastal watershed to complete the length distribution. Spring adults had a high gonadosomatic index compared with autumn (fall) adults, which had atresia. No eggs or age-0 fish were captured in the lake during summer. The four length cohorts matched growth and back-calculated length at age. Otoliths were linearly related to fish length and were used for ageing and growth calculations. Although we found no direct evidence of spawning, data compilation suggests that Atlantic needlefish could be using this lake for reproduction.

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Older but not wider. Impacts of molt frequency variation on age and growth dynamics of Newfoundland & Labrador snow crab (Chionoecetes opilio) toward corroborating gastric mill 2 age estimations

10.21203/rs.3.rs-1044348/v1 ◽

2021 ◽

Author(s):

Darrell Mullowney ◽

Nicole O’Connell ◽

Rémy Rochette ◽

Raouf Kilada

Keyword(s):

Estimation Error ◽

Growth Dynamics ◽

Age And Growth ◽

Future Research ◽

Snow Crab ◽

Frequency Variation ◽

Gastric Mill ◽

Age At Maturity ◽

Chionoecetes Opilio ◽

Size At Age

Abstract Aging specimen and survey data from a heterogeneous stock range are combined to investigate effects of molt frequency variation on age and growth dynamics and efficacy of gastric mill age band estimations in snow crab. A central assumption that bands form independent of molting is examined through analyses of molt frequency variation with an overall result of support for the hypothesis that gastric mill bands form independent of molting. This is based on an applied review approach, demonstrating blind age estimation results within and across population units featuring different rates of molt frequency interruptions in context of literature-based expected outcomes of age and growth dynamics. The comprehensive analyses overall supports the ability of gastric mill bands to track chronological ages, but non-fully explained outcomes of growth delays into sexual maturity stages in males and potential estimation error in 1-3 year old crab preclude a conclusion that absolute ages are consistently tracked throughout ontogeny. The results suggest gastric mill bands continue to form during both skip-molts and after terminal molt. Despite uncertainties, the research highlights that males originating from populations where skip-molting is prominent are older reaching fishery size than previously thought (9-10 years), with tentative average estimates of 10-12 years. The study presents novel observations of size-at-age and age-at-maturity in Newfoundland & Labrador (NL) snow crab and broadens life history knowledge for the species. Along with corroborating gastric mill age band estimations, the study reveals future research streams to further help advance the discipline of aging crustaceans [247].

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Growth dynamics of freshwater crocodiles (Crocodylus johnstoni) in the Lynd River, Queensland

Australian Journal of Zoology ◽

10.1071/zo06099 ◽

2006 ◽

Vol 54 (6) ◽

pp. 409 ◽

Cited By ~ 19

Author(s):

Anton D. Tucker ◽

Colin J. Limpus ◽

Keith R. McDonald ◽

Hamish I. McCallum

Keyword(s):

Growth Models ◽

Growth Dynamics ◽

Interval Data ◽

Age And Growth ◽

Data Sets ◽

Size Dimorphism ◽

Crocodylus Johnstoni ◽

Trade Offs ◽

Capture Recapture ◽

Australian Freshwater

We analysed growth models for a population of Australian freshwater crocodiles (Crocodylus johnstoni). Competing growth models were tested with two data sets: individuals of known-age, and growth interval data from capture-recapture records. A von Bertalanffy function provided the best empirical fit of several growth models. The estimated asymptotic lengths (snout–vent length of males = 125.3 cm; females = 97.4 cm) agreed well with average lengths of the ten largest males and females in the population. Sexual size dimorphism in this species resulted from a combination of smaller mean length at maturity for females and a subsequent decline in female growth rate. Size dimorphism may result from individual trade-offs in age v. length at maturity as a consequence of sexual selection.

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Cristal-growth dynamics of n-doped gaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100132352 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1544-1545

Author(s):

Pham V. Huong ◽

Stéphanie Bouchet ◽

Jean-Claude Launay

Keyword(s):

Crystal Growth ◽

Spatial Resolution ◽

Epitaxial Layer ◽

Outer Surface ◽

Gaas Substrate ◽

Structural Modification ◽

Growth Dynamics ◽

Argon Laser ◽

High Anisotropy ◽

Crystal Gaas

Microstructure of epitaxial layers of doped GaAs and its crystal growth dynamics on single crystal GaAs substrate were studied by Raman microspectroscopy with a Dilor OMARS instrument equipped with a 1024 photodiode multichannel detector and a ion-argon laser Spectra-Physics emitting at 514.5 nm.The spatial resolution of this technique, less than 1 μm2, allows the recording of Raman spectra at several spots in function of thickness, from the substrate to the outer deposit, including areas around the interface (Fig.l).The high anisotropy of the LO and TO Raman bands is indicative of the orientation of the epitaxial layer as well as of the structural modification in the deposit and in the substrate at the interface.With Sn doped, the epitaxial layer also presents plasmon in Raman scattering. This fact is already very well known, but we additionally observed that its frequency increases with the thickness of the deposit. For a sample with electron density 1020 cm-3, the plasmon L+ appears at 930 and 790 cm-1 near the outer surface.

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