In situ growth rate estimates of Southern Ocean krill, Thysanoessa macrura

2019 ◽  
Vol 31 (3) ◽  
pp. 116-122 ◽  
Author(s):  
Jake R. Wallis ◽  
Jessica E. Melvin ◽  
Robert King ◽  
So Kawaguchi
Keyword(s):  
Growth Rate ◽  
Southern Ocean ◽  
Growth Rates ◽  
Somatic Growth ◽  
Growth Patterns ◽  
Daily Growth ◽  
Thysanoessa Macrura ◽  
Growth Method ◽  
Repeated Sampling ◽  
The Antarctic

AbstractGrowth, which is intrinsically linked to environmental conditions including temperature and food availability are highly variable both temporally and spatially. Estimates of growth rates of the Southern Ocean euphausiid Thysanoessa macrura are currently restricted to limited studies which rely upon repeated sampling and length-frequency analysis to quantify growth rates. The instantaneous growth method (IGR) was used to measure the growth rate of T. macrura successfully in the southern Kerulen Plateau region during summer, providing the first IGR parameters for the Southern Ocean euphausiid species. Results of the four-day IGR incubation indicate a period of low somatic growth for adult T. macrura. Males had a longer intermoult period (IMP) (62 days) than females (42 days), but the sexes exhibited similar daily growth rates of 0.011 mm day−1 and 0.012 mm day−1 respectively. Juveniles exhibited the fastest growth, with an IMP of 13 days and daily growth rate of 0.055 mm day−1 indicating a prolonged growth season, similar to the Antarctic krill E. superba. Consequently, we highlight the usability of the IGR method and strongly encourage its use in developing a comprehensive understanding of spatial and seasonal growth patterns of T. macrura.

Daily growth rates and hatch date distributions of common two-banded seabream, Diplodus vulgaris inhabiting the Çanakkale shallow waters of Turkey

2014 ◽  
Vol 95 (1) ◽  
pp. 185-191 ◽  
Author(s):  
Hakan Ayyildiz ◽  
Ozcan Ozen ◽  
Aytac Altin
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Somatic Growth ◽  
Analysis Of Covariance ◽  
Shallow Waters ◽  
Daily Growth ◽  
Data Set ◽  
Sea Temperature ◽  
Growth Equations ◽  
Otolith Microstructure Analysis

Otolith microstructure analysis was used to determine daily age, growth rate and hatching periods of young of the year (YOY) common two-banded seabream, Diplodus vulgaris, collected at two sites by using beach seine from Çanakkale shallow waters between January and December 2007. Total length of the YOY D. vulgaris was between 12 and 86 mm and the daily ages ranged between 42 and 313 days. Somatic growth rate estimated by fitting a linear regression to the age–length data set was calculated as 0.273 mm day−1. According to the length–age regression analysis, maximum daily growth rates were found 0.277 mm day−1 in the lowest sea temperature period and minimum values of 0.274 mm day−1 were observed in the declining sea temperature period. Analysis of covariance indicated that there were no significant differences in the linear growth equations for the two cohorts (F = 0.4008, P = 0.527). Hatching period of the YOY was estimated to occur between October and March with relatively higher frequency in January. This study has shown that YOY D. vulgaris is a winter spawner in the Çanakkale shallow waters.

scholarly journals Age, growth, and recruitment patterns of juvenile ladyfish (Elopssp) from the east coast of Florida (USA)

PeerJ ◽  
2015 ◽  
Vol 3 ◽  
pp. e1392
Author(s):  
Juan C. Levesque
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Age And Growth ◽  
Growth Equation ◽  
Length Frequency ◽  
Daily Growth ◽  
Exponential Regression ◽  
Absolute Growth ◽  
Specific Growth Rates ◽  
Size At Age

Ladyfish (Elopssp) are a common and economically valuable coastal nearshore species found along coastal beaches, bays, and estuaries of the southeastern United States, and subtropical and tropical regions worldwide. Previously, ladyfish were a substantial bycatch in Florida’s commercial fisheries, but changes in regulations significantly reduced commercial landings. Today, ladyfish are still taken in commercial fisheries in Florida, but many are also taken by recreational anglers. Life-history information and research interest in ladyfish is almost non-existent, especially information on age and growth. Thus, the overarching purpose of this study was to expand our understanding of ladyfish age and growth characteristics. The specific objectives were to describe, for the first time, age, growth, and recruitment patterns of juvenile ladyfish from the east coast of Florida (USA). In the Indian River Lagoon (IRL), annual monthly length-frequency distributions were confounded because a few small individuals recruited throughout the year; monthly length-frequency data generally demonstrated a cyclical pattern. The smallest were collected in September and the largest in May. Post-hoc analysis showed no significant difference in length between August and May, or among the other months. In Volusia County (VC), annual monthly length-frequency distribution demonstrated growth generally occurred from late-winter and spring to summer. The smallest ladyfish were collected in February and the largest in August. On average, the absolute growth rate in the IRL was 36.3 mm in 60 days or 0.605 mm day−1. Cohort-specific daily growth rates, elevations, and coincidentals were similar among sampling years. Cohort-specific growth rates ranged from 1.807 in 1993 to 1.811 mm day−1in 1994. Overall, growth was best (i.e., goodness of fit) described by exponential regression. On average, the absolute growth rate in VC was 28 mm in 150 days or 0.1866 mm day−1. Cohort-specific daily growth rates were significantly different among sampling years; however, the elevations and coincidentals were similar. Cohort-specific growth rates ranged from 1.741 in 1994 to 1.933 mm day−1in 1993. Mean ladyfish growth was best described by linear regression; however, natural growth was explained better by exponential regression. In the IRL, the corrected exponential growth equation yielded a size-at-age 1 of 156.0 mm SL, which corresponded to an estimated growth rate of 0.4356 mm day−1. In VC, the corrected exponential growth equation yielded a size-at-age 1 of 80 mm SL corresponding to an estimated growth rate of 0.2361 mm day−1.

Abstract 13513: Serial CT Surveillance of Abdominal Aortic Aneurysm Diameter Demonstrates Predominantly Linear Growth (N-TA 3 CT)

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Sydney Olson ◽  
Marniker Wijesinha ◽  
Annalise Panthofer ◽  
William Blackwelder ◽  
Gilbert R Upchurch ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Linear Growth ◽  
Growth Patterns ◽  
Aortic Aneurysms ◽  
Transverse Diameter ◽  
Invasive Treatment ◽  
Abdominal Aortic ◽  
Risk Of Rupture ◽  
Serial Ct

Objective: Small abdominal aortic aneurysms (AAAs) have a low risk of rupture. Intervention is indicated when diameters exceed established thresholds. This study assessed the growth rates and patterns of AAAs over 2 years as documented on serial CT scans from the Non-Invasive Treatment of AAA Clinical Trial. Methods: 254 patients, 35 females with baseline AAA maximum transverse diameter (MTD) between 3.5-4.5 cm and 219 males with baseline MTD 3.5-5.0 cm, were included in this study. Linear regressions and segmental growth rates were used to model growth rates and patterns. Results: The yearly growth rates of AAA MTDs had a median of 0.17 cm/yr and mean of 0.19 cm/yr ± 0.14 (Figure 1). 10% of AAA displayed minimal to no growth (< 0.05 cm/yr), 62% low growth (0.05-0.25 cm/yr), 28% high growth (> 0.25 cm/yr). Baseline AAA diameter accounted for only 5.4% of growth rate variance (P<0.001, R 2 0.05). Most AAAs displayed linear growth (70%); large variations in interval growth rates occurred infrequently (3% staccato growth, 4% exponential growth); a minority of subjects’ growth patterns were not clearly classifiable (11% indeterminate-not growing, 12% indeterminate-growing) (Figure 2). No patients with baseline MTD < 4.25 cm exceeded sex-specific repair thresholds (males 0 / 92, [95% CI, 0.00-0.06]; females 0 / 25 [95% CI, 0.00-0.25]) in the course of follow-up for as long as two years. Conclusions: The majority of small AAAs exhibit linear growth; large intra-patient growth rate variations were infrequently observed over 2 years. AAA < 4.25 cm can be followed with a CT scan in 2 years with little chance of exceeding interventional MTD thresholds of 5.5 cm for men.

scholarly journals Radial Growth Patterns Associated with Tree Mortality in Nothofagus pumilio Forest

Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 489 ◽  
Author(s):  
Milagros Rodríguez-Catón ◽  
Ricardo Villalba ◽  
Ana Srur ◽  
A. Park Williams
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Forest Dynamics ◽  
Radial Growth ◽  
Tree Mortality ◽  
Growth Patterns ◽  
Severe Drought ◽  
Nothofagus Pumilio ◽  
Total Size ◽  
Growth Trends

Tree mortality is a key process in forest dynamics. Despite decades of effort to understand this process, many uncertainties remain. South American broadleaf species are particularly under-represented in global studies on mortality and forest dynamics. We sampled monospecific broadleaf Nothofagus pumilio forests in northern Patagonia to predict tree mortality based on stem growth. Live or dead conditions in N. pumilio trees can be predicted with high accuracy using growth rate as an explanatory variable in logistic models. In Paso Córdova (CO), Argentina, where the models were calibrated, the probability of death was a strong negative function of radial growth, particularly during the six years prior to death. In addition, negative growth trends during 30 to 45 years prior to death increased the accuracy of the models. The CO site was affected by an extreme drought during the summer 1978–1979, triggering negative trends in radial growth of many trees. Individuals showing below-average and persistent negative trends in radial growth are more likely to die than those showing high growth rates and positive growth trends in recent decades, indicating the key role of droughts in inducing mortality. The models calibrated at the CO site showed high verification skill by accurately predicting tree mortality at two independent sites 76 and 141 km away. Models based on relative growth rates showed the highest and most balanced accuracy for both live and dead individuals. Thus, the death of individuals across different N. pumilio sites was largely determined by the growth rate relative to the total size of the individuals. Our findings highlight episodic severe drought as a triggering mechanism for growth decline and eventual death for N. pumilio, similar to results found previously for several other species around the globe. In the coming decades, many forests globally will be exposed to more frequent and/or severe episodes of reduced warm-season soil moisture. Tree-ring studies such as this one can aid prediction of future changes in forest productivity, mortality, and composition.

Ecological Traits of the Eucalyptus L'hérit Subgenera Monocalyptus and Symphyomyrtus

1989 ◽  
Vol 37 (3) ◽  
pp. 207 ◽  
Author(s):  
IR Noble
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Root Morphology ◽  
Related Species ◽  
Early Growth ◽  
Growth Patterns ◽  
Leaf Chemistry ◽  
Ecological Traits ◽  
Closely Related Species ◽  
Genus Eucalyptus

The genus Eucalyptus L'Hérit. dominates most of the forests and woodlands of Australia. Many stands consist of intimate mixtures of species from different subgenera. The ecological traits of the two largest subgenera, Symphyomyrtus and Monocalyptus, are reviewed. Consistent differences in herbivore and parasite damage to leaves; in water relations; in tolerance to waterlogging, flooding, salinity and frost; in nutrient usage; in response to Phytophthora cinnamorni; and in early growth patterns are described. These can be summarised as differences in leaf chemistry; in root morphology, chemistry and activity; and in early growth rates. It is suggested that the differences in the ecological traits, and especially in the early growth rate, may help explain the coexistence of closely related species of similar habits in eucalypt communities.

Growth ecology of the tree lizard Urosaurus bicarinatus (Squamata: Phrynosomatidae), in a tropical dry forest of the Chamela Region, Mexico

2016 ◽  
Vol 66 (2) ◽  
pp. 189-199 ◽  
Author(s):  
Aurelio Ramírez-Bautista ◽  
Uriel Hernández-Salinas ◽  
J. Gastón Zamora-Abrego
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Growth Rates ◽  
Average Rate ◽  
Growth Patterns ◽  
Dry Forest ◽  
Von Bertalanffy ◽  
Mexican Pacific ◽  
Males And Females ◽  
Tree Lizard

Determination of growth rate provides an important component of an organism’s life history, making estimations of size at maturity, survival rate, and longevity possible. Here, we report on growth rate of males and females of the tropical tree lizard Urosaurus bicarinatus, in a seasonal environment in the state of Jalisco on the Mexican Pacific Coast. We calculated body growth rates and fitted these to the Von Bertalanffy, the logistic-by-length, and the logistic-by-weight growth models. The Von Bertalanffy model provided the best fit, and we used it to analyze the growth pattern. Males and females did not differ in estimated asymptotic size and other characteristic growth parameters. Estimated growth curve predicted an age at maturity of 38 mm SVL on 120 days for males, and 40 mm SVL on 170 days for females. On the basis of the similarities in the growth rates between the sexes, comparisons were made between seasons, and we found that the average rate of growth was slightly, albeit insignificantly, higher in the rainy season than in the dry season. The similarities in the growth patterns for the sexes of this species might be indicative of variance in its life history traits (e.g., fecundity, egg size) compared to those of other populations of this species and other species of this genus; therefore, it is important to document interpopulation differences to understand the evolutionary changes that have led to optimal adaptation in a particular environment more accurately.

scholarly journals Age, growth, and recruitment patterns of juvenile ladyfish (Elops sp) from the east coast of Florida (USA)

2015 ◽  
Author(s):  
Juan C Levesque
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Age And Growth ◽  
Growth Equation ◽  
Length Frequency ◽  
Daily Growth ◽  
Exponential Regression ◽  
Absolute Growth ◽  
Specific Growth Rates ◽  
Size At Age

Ladyfish (Elops sp) are a common and economically valuable coastal nearshore species found along coastal beaches, bays, and estuaries of the southeastern United States, and subtropical and tropical regions worldwide. Previously, ladyfish were a substantial bycatch in Florida’s commercial fisheries, but changes in regulations significantly reduced commercial landings. Today, ladyfish are still taken in commercial fisheries in Florida, but many are also taken by recreational anglers. Life-history information and research interest in ladyfish is almost non-existent, especially information on age and growth. Thus, the overarching purpose of this study was to expand our understanding of ladyfish age and growth characteristics. The specific objectives were to describe, for the first time, age, growth, and recruitment patterns of juvenile ladyfish from the east coast of Florida (USA). In the Indian River Lagoon (IRL), annual monthly length-frequency distributions were confounded because a few small individuals recruited throughout the year; monthly length-frequency data generally demonstrated a cyclical pattern. The smallest were collected in September and the largest in May. Post-hoc analysis showed no significant difference in length between August and May, or among the other months. In Volusia County (VC), annual monthly length-frequency distribution demonstrated growth generally occurred from late-winter and spring to summer. The smallest ladyfish were collected in February and the largest in August. On average, the absolute growth rate in the IRL was 36.3 mm in 60 days or 0.605 mm day-1. Cohort-specific daily growth rates, elevations, and coincidentals were similar among sampling years. Cohort-specific growth rates ranged from 1.807 in 1993 to 1.811 mm day-1 in 1994. Overall, growth was best (i.e., goodness of fit) described by exponential regression. On average, the absolute growth rate in VC was 28 mm in 150 days or 0.1866 mm day-1. Cohort-specific daily growth rates were significantly different among sampling years; however, the elevations and coincidentals were similar. Cohort-specific growth rates ranged from 1.741 in 1994 to 1.933 mm day-1 in 1993. Mean ladyfish growth was best described by linear regression; however, natural growth was explained better by exponential regression. In the IRL, the corrected exponential growth equation yielded a size-at-age 1 of 156.0 mm SL, which corresponded to an estimated growth rate of 0.4356 mm day-1. In VC, the corrected exponential growth equation yielded a size-at-age 1 of 80 mm SL corresponding to an estimated growth rate of 0.2361 mm day-1.

scholarly journals Age, growth, and recruitment patterns of juvenile ladyfish (Elops sp) from the east coast of Florida (USA)

2015 ◽  
Author(s):  
Juan C Levesque
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Age And Growth ◽  
Growth Equation ◽  
Length Frequency ◽  
Daily Growth ◽  
Exponential Regression ◽  
Absolute Growth ◽  
Specific Growth Rates ◽  
Size At Age

Ladyfish (Elops sp) are a common and economically valuable coastal nearshore species found along coastal beaches, bays, and estuaries of the southeastern United States, and subtropical and tropical regions worldwide. Previously, ladyfish were a substantial bycatch in Florida’s commercial fisheries, but changes in regulations significantly reduced commercial landings. Today, ladyfish are still taken in commercial fisheries in Florida, but many are also taken by recreational anglers. Life-history information and research interest in ladyfish is almost non-existent, especially information on age and growth. Thus, the overarching purpose of this study was to expand our understanding of ladyfish age and growth characteristics. The specific objectives were to describe, for the first time, age, growth, and recruitment patterns of juvenile ladyfish from the east coast of Florida (USA). In the Indian River Lagoon (IRL), annual monthly length-frequency distributions were confounded because a few small individuals recruited throughout the year; monthly length-frequency data generally demonstrated a cyclical pattern. The smallest were collected in September and the largest in May. Post-hoc analysis showed no significant difference in length between August and May, or among the other months. In Volusia County (VC), annual monthly length-frequency distribution demonstrated growth generally occurred from late-winter and spring to summer. The smallest ladyfish were collected in February and the largest in August. On average, the absolute growth rate in the IRL was 36.3 mm in 60 days or 0.605 mm day-1. Cohort-specific daily growth rates, elevations, and coincidentals were similar among sampling years. Cohort-specific growth rates ranged from 1.807 in 1993 to 1.811 mm day-1 in 1994. Overall, growth was best (i.e., goodness of fit) described by exponential regression. On average, the absolute growth rate in VC was 28 mm in 150 days or 0.1866 mm day-1. Cohort-specific daily growth rates were significantly different among sampling years; however, the elevations and coincidentals were similar. Cohort-specific growth rates ranged from 1.741 in 1994 to 1.933 mm day-1 in 1993. Mean ladyfish growth was best described by linear regression; however, natural growth was explained better by exponential regression. In the IRL, the corrected exponential growth equation yielded a size-at-age 1 of 156.0 mm SL, which corresponded to an estimated growth rate of 0.4356 mm day-1. In VC, the corrected exponential growth equation yielded a size-at-age 1 of 80 mm SL corresponding to an estimated growth rate of 0.2361 mm day-1.

Estimating larval fish growth under size-dependent mortality: a numerical analysis of bias

2007 ◽  
Vol 64 (3) ◽  
pp. 554-562 ◽  
Author(s):  
Tian Tian ◽  
Øyvind Fiksen ◽  
Arild Folkvord
Keyword(s):  
Growth Rate ◽  
Longitudinal Data ◽  
Growth Rates ◽  
Mortality Rates ◽  
Growth Patterns ◽  
Cross Sectional ◽  
Larval Phase ◽  
Size Dependent ◽  
Recruitment Success ◽  
Dependent Mortality

The early larval phase is characterized by high growth and mortality rates. Estimates of growth from both population (cross-sectional) and individual (longitudinal) data may be biased when mortality is size-dependent. Here, we use a simple individual-based model to assess the range of bias in estimates of growth under various size-dependent patterns of growth and mortality rates. A series of simulations indicate that size distribution of individuals in the population may contribute significantly to bias in growth estimates, but that typical size-dependent growth patterns have minor effects. Growth rate estimates from longitudinal data (otolith readings) are closer to true values than estimates from cross-sectional data (population growth rates). The latter may produce bias in growth estimation of about 0.03 day–1 (in instantaneous, specific growth rate) or >40% difference in some situations. Four potential patterns of size-dependent mortality are tested and analyzed for their impact on growth estimates. The bias is shown to yield large differences in estimated cohort survival rates. High autocorrelation and variance in growth rates tend to increase growth estimates and bias, as well as recruitment success. We also found that autocorrelated growth patterns, reflecting environmental variance structure, had strong impact on recruitment success of a cohort.

Daily Growth Rates as Indicated by Valve Ridges in Postlarval Giant Scallop (Placopecten magellanicus) (Bivalvia: Pectinidae)

1993 ◽  
Vol 50 (3) ◽  
pp. 456-464 ◽  
Author(s):  
G. Jay Parsons ◽  
Shawn M. C. Robinson ◽  
John C. Roff ◽  
Michael J. Dadswell
Keyword(s):  
Growth Rates ◽  
Larval Fish ◽  
Shell Height ◽  
Age Determination ◽  
Growth Patterns ◽  
Placopecten Magellanicus ◽  
Short Term ◽  
Daily Growth ◽  
Alizarin Red ◽  
Growth Increments

Postlarval giant scallop (Placopecten magellanicus) were examined for daily growth ridges and growth rates by marking the dissoconch shell with Alizarin red dye. The surface of the left valve of postlarvae was composed of concentric ridges, each consisting of a series of irregularly shaped raised nodules. Ridges were clear and distinct in newly settled scallop between ≈0.25 and 2.0 mm shell height. The shell of postlarvae >2 mm was pigmented and ribbed and ridges were no longer distinguishable. Estimated age was significantly correlated with actual age, suggesting that growth ridges were produced daily, under the environmental conditions of Passamaquoddy Bay. Mean growth rate ranged from 32 to 57 μm∙d−1 and was proportional to size and age, but growth of individual scallop showed no coherence in their daily growth patterns. The short-term growth ridges in postlarval giant scallop can be used to determine age and can be applied to comparative growth, mortality, and recruitment studies of newly settled individuals <2.0 mm (≈40 d old postsettlement). The high accuracy and precision of age determination for postlarval scallop differs from studies of short-term internal growth increments of bivalve shells and larval fish otoliths.

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