Using r-K Selection Theory to Predict Natural Mortality

1980 ◽  
Vol 37 (12) ◽  
pp. 2266-2271 ◽  
Author(s):  
Donald R. Gunderson
Keyword(s):  
Body Weight ◽  
Life History ◽  
Growth Parameters ◽  
Stepwise Multiple Regression ◽  
Natural Mortality ◽  
Instantaneous Rate ◽  
Life History Parameters ◽  
Selection Theory ◽  
Weight Index ◽  
Body Weight Index

Theory on r-K selection is used as a basis for examining correlations between instantaneous rate of natural mortality (M), gonad-body weight index, age at maturity, longevity, and Bertalanffy growth parameters (k, L∞) for 10 species of marine fish. All correlations were consistent with r-K selection theory. The gonad-body weight index was found to be more highly correlated with M than any of the other life history parameters examined (r2 = 0.62), and stepwise multiple regression showed that additional variables added little to the predictive ability of the model. The gonad-body weight index appears to be quite useful in predicting M, and development of an analogous index on an energetics basis might enhance its utility in this regard.Key words: natural mortality, r-K selection, life history parameters

scholarly journals Natural mortality estimation using tree-based ensemble learning models

2020 ◽  
Vol 77 (4) ◽  
pp. 1414-1426 ◽  
Author(s):  
Chanjuan Liu ◽  
Shijie Zhou ◽  
You-Gan Wang ◽  
Zhihua Hu
Keyword(s):  
Life History ◽  
Ensemble Learning ◽  
Random Forests ◽  
Growth Parameters ◽  
Training Dataset ◽  
Natural Mortality ◽  
Statistical Regression ◽  
Learning Models ◽  
Empirical Methods ◽  
Life History Parameters

Abstract Empirical studies are popular in estimating fish natural mortality rate (M). However, these empirical methods derive M from other life-history parameters and are often perceived as being less reliable than direct methods. To improve the predictive performance and reliability of empirical methods, we develop ensemble learning models, including bagging trees, random forests, and boosting trees, to predict M based on a dataset of 256 records of both Chondrichthyes and Osteichthyes. Three common life-history parameters are used as predictors: the maximum age and two growth parameters (growth coefficient and asymptotic length). In addition, taxonomic variable class is included to distinguish Chondrichthyes and Osteichthyes. Results indicate that tree-based ensemble learning models significantly improve the accuracy of M estimate, compared to the traditional statistical regression models and the basic regression tree model. Among ensemble learning models, boosting trees and random forests perform best on the training dataset, but the former performs a slightly better on the test dataset. We develop four boosting trees models for estimating M based on varying life-history parameters, and an R package is provided for interested readers to estimate M of their new species.

The Evolution of Life History Parameters in Teleosts

1984 ◽  
Vol 41 (6) ◽  
pp. 989-1000 ◽  
Author(s):  
Derek A. Roff
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Life History Theory ◽  
Larval Survival ◽  
Reasonable Assumption ◽  
Natural Mortality ◽  
Age At First Reproduction ◽  
Life History Parameters ◽  
First Case ◽  
First Reproduction

Empirical studies have shown that in teleosts there is a significant correlation between the life history parameters, age at first reproduction, natural mortality, and growth rate. In this paper 1 hypothesize that these correlations are the result of evolutionary adjustments due to the trade-off between reproduction, growth, and survival. A simple and reasonable assumption is that the costs of reproduction are sufficient to cause the ltmt function to decrease. A simple expression relating the age at first reproduction is derived from this assumption. This formula accounts for a statistically significant portion (60.6%) of the variation in age at first reproduction in 30 stocks of fish. To extend the model to predict the distribution of life history parameters across all teleosts, an explicit cost function is incorporated. The model is analyzed with respect to two fitness measures, the expected lifetime fecundity and malthusian parameter, r. In the first case it is shown that the optimal age at maturity, T, depends only on the natural mortality rate (M) and the growth rate (k). In the second case, T is a function of k and the logarithm of a parameter, In C; the latter is a product of egg and larval survival, maximum body length (Lx), and the proportionality coefficient of the fecundity/length function. Difficulties of measuring egg and larval survival make the testing of the latter case difficult for particular species. However, this method provides a simple formula for the computation of r; this is shown generally to be approximately zero, thereby adding strength to the assumptions of the first analysis. The distribution patterns of T on k and M on k are predicted and compared with the observed pattern. In general, the predictions are validated: however, certain combinations of k and ln C are shown to occur very infrequently. The prediction of such "empty" regions of the parameter space remains a challenge for future development of life history theory.

Correlation of Allograft Weight to Recipient Body Weight Index on Renal Function in Kidney Transplantation

2016 ◽  
Vol 48 (2) ◽  
pp. 578-582 ◽  
Author(s):  
L. García-Covarrubias ◽  
C. Pliego ◽  
L. Bermudez ◽  
A. Cicero ◽  
J. Cancino ◽  
...  
Keyword(s):  
Renal Function ◽  
Body Weight ◽  
Kidney Transplantation ◽  
Weight Index ◽  
Body Weight Index

scholarly journals Preliminary Estimates of Age, Growth and Natural Mortality of Margate, Haemulon album, and Black Margate, Anisotremus surinamensis, from the Southeastern United States

Fishes ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 44
Author(s):  
Michael L. Burton ◽  
Jennifer C. Potts ◽  
Andrew D. Ostrowski
Keyword(s):  
United States ◽  
Life History ◽  
Atlantic Coast ◽  
Southeastern United States ◽  
Geographic Region ◽  
Fish Growth ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Life History Parameters ◽  
Growth Equations

Ages of margate, Haemulon album (n = 415) and black margate, Anisotremus surinamensis (n = 130) were determined using sectioned sagittal otoliths collected from the Southeastern United States Atlantic coast from 1979 to 2017. Opaque zones were annular, forming between January and June for both species, with peaks in occurrence of otoliths with opaque margins in April for margate and March for black margate. The observed ages for margate were 0–22 years, and the largest fish measured 807 mm TL (total length). Black margate ranged in age from 3 to 17 years, and the largest fish was 641 mm TL. Weight–length relationships were: margate, ln(W) = 2.88 ln(TL) − 10.44 (n = 1327, r2 = 0.97, MSE = 0.02), where W is total weight (grams, g); black margate, ln(W) = 3.02 ln(TL) − 11.10 (n = 451, r2 = 0.95, MSE = 0.01). Von Bertalanffy growth equations were Lt = 731 (1 − e−0.23(t+0.38)) for margate, and Lt = 544 (1 − e−0.13(t+2.61)) for black margate. After re-estimating black margate growth using a bias-correction procedure to account for the lack of younger fish, growth was described by the equation Lt = 523 (1 − e−0.18(t+0.0001)). Age-invariant estimates of natural mortality were M = 0.19 y−1 and M = 0.23 y−1 for margate and black margate, respectively, while age-varying estimates of M ranged from 2.93 −0.23 y−1 for fish aged 0–22 for margate and 7.20 − 0.19 y−1 for fish aged 0–18 for black margate. This study presents the first documentation of life-history parameters for margate from the Atlantic waters off the Southeastern United States, and the first published estimate of black margate life history parameters from any geographic region.

Reproductive biology, age and growth of the two-banded seabream Diplodus vulgaris (Pisces: Sparidae) in the Gulf of Gabès, Tunisia

2013 ◽  
Vol 93 (5) ◽  
pp. 1415-1421 ◽  
Author(s):  
Aymen Hadj Taieb ◽  
Mohamed Ghorbel ◽  
Nader Ben Hadj Hamida ◽  
Othman Jarboui
Keyword(s):  
Growth Parameters ◽  
Age And Growth ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Spawning Activity ◽  
Gulf Of Gabes ◽  
Instantaneous Rate ◽  
Total Length ◽  
Gulf Of Gabès ◽  
Overall Ratio

Samples of common two-banded seabream Diplodus vulgaris (N = 1097), used in this study, were caught in the Gulf of Gabès (Tunisia) from March 2008 to February 2010. Total length ranged from 7 to 25 cm. Diplodus vulgaris is a protandric hermaphrodite. The overall ratio of females to males was 1:1.66. The reproductive season extended from October to February, and the peak spawning activity occurred in December–January. The total length at which 50% of the population reached maturity was 14.14 ± 0.16 cm for females and 13.57 ± 0.01 cm for males. Parameters of the length–weight relationship (TW = aTLb) for all individuals were a = 0.0185 and b = 2.9319. The youngest specimen in this study was 0+ years, whereas the oldest one was 9 years. The von Bertalanffy growth parameters for the whole sample were: L∞ = 25.4 cm, k = 0.179 and t0 = −1.631 year. The instantaneous rate of natural mortality was: M = 0.333 year−1.

Investigation of the influence of body weight index to the result of therapeutic erythrocytapheresis in patients with polycythemia vera

2012 ◽  
Vol 47 (3) ◽  
pp. 295-299 ◽  
Author(s):  
Jie Bai ◽  
Lei Zhang ◽  
Xiao Hu ◽  
Yangping Xue ◽  
Fenglei Long ◽  
...  
Keyword(s):  
Body Weight ◽  
Polycythemia Vera ◽  
Weight Index ◽  
Body Weight Index

scholarly journals Acute toxicity impacts of Euphorbia hirta L extract on behavior, organs body weight index and histopathology of organs of the mice and Artemia salina

2012 ◽  
Vol 4 (3) ◽  
pp. 170 ◽  
Author(s):  
Sreenivasan Sasidharan ◽  
YuetPing Kwan ◽  
LachimananYoga Latha ◽  
Mohammad AbuBasma Rajeh ◽  
Zuraini Zakaria ◽  
...  
Keyword(s):  
Body Weight ◽  
Acute Toxicity ◽  
Artemia Salina ◽  
Euphorbia Hirta ◽  
Weight Index ◽  
Body Weight Index
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