Study Of Relative Growth Research Articles

Morphological Diversity of Different Male Morphotypes of Giant Freshwater Prawn Macrobrachium rosenbergii (De Man, 1879)

The giant freshwater prawn (GFP), Macrobrachium rosenbergii, is one of the largest palaemonids in the world, found in tropical marine, estuarine, and freshwaters, and is among the most commercially cultured crustaceans. According to research, mature males usually develop differences in cheliped morphology, growth characteristics, and agonistic behavior. The identification of such morphotypes is critical for effectively managing and handling prawns. The present study aimed to describe the GFP male population structure in culture ponds (the Yangtze River delta, China). Sixteen morphometric traits and four weight data were measured for each four male morphotype. Principal component and clustering analyses were conducted to investigate the morphological variation among the four morphotypes. The study of relative growth was also employed to estimate the growth patterns of body structures (dependent variables) in relation to the carapace length (independent variable). A detailed description of the cheliped’s macroscopic characteristics that differed among morphotypes was provided, which corroborated with previous studies of the species. The four morphotypes were statistically different regarding the cheliped morphology, size, and morphometric relationships and equations, indicating a considerable variation in growth among the four male morphotypes. The present results contribute to a clear understanding of the population biology of GFP and support future management and broodstock selection activities.

A simple method for classifying data in relative growth analysis of crustaceans

Abstract Relative growth in crustaceans is a topic of quite high importance that allows, among other things, to estimate their size at the onset of morphometric sexual maturity. In this process, it is usual to start from a transition point and then generate regressions that reflect phases of the sexual development of the individuals (i.e., mature and immature). There are several statistical methods that allow data to be classified into subsets, but according to the specific growth pattern at issue, those methods may or may not be usable. This paper proposes a simple method to classify data into two subsets, viz., when they are overlapping over a wide range of sizes. The actual procedure consists of a linear regression that divides the data. Subsequently, a linear regression is applied to the groups generated by adjusting the parameters through maximum log-likelihood. The observed values will be classified according to the smallest residual difference generated with each regression line. The proposed method was tested by separating the sexes of Goyazana castelnaui, using real data. The efficiency of the method was analysed based on the percentage value between the number of total data and the number of correctly classified data. Additionally, the k-mean cluster was used as a conventional method, the results of which were reclassified by a linear discriminant analysis. The efficiency of the proposed method was >80% while that of the conventional method was >60%. The values misclassified by the proposed method were mixed with those of the opposite sex, so it was expected to fail in those cases. The proposed method is a simple alternative that can serve as a basis for subsequent morphometric analysis, especially for acquiring an initial insight in the structure of a dataset collected for a study of relative growth.

General and Relative Growth Studies in Formulated Feed of Fresh Water Prawn M. Assamensis peninsularis (Tiwari) from Kumaon Himalaya, Uttarakhand

The present paper deals with the study of relative growth of fresh water prawn Macrobrachium assamensis peninsularis. Experiment was conducted to study the effect of different formulated diets. The experiment diets were prepared with similar ingredient composition with only difference in protein supplement source. The stocked animals were fed with control diet (D0) and three experimental diets (D1-D3). The food was given at 8 am and 4 pm at the rate of 5% of the total biomass. Study was conducted during July 2007- June 2008. The relative per month growth increment was observed maximum in the case of animal fed with diet D3 followed by animal fed with diet D2. It was 2.08 mm in male and 1.44 in female for per month increment in length of animal fed with diet D3 and 0.11 gm in males and 0.073 gm in females for per month increment in weight of the same group of animals. Finally concluded that formulated feed to enhanced the relative growth of both the sexes under laboratory condition.

Highly luminescent and biocompatible,l-citrulline-capped ZnS:Mn nanocrystals for rapid screening of metal accumulatingLysinibacillus fusiformisbacteria

Biocompatible and highly luminescent manganese doped zinc sulfide (ZnS:Mn) nanocrystals of average particle size 10 nm have been synthesized by capping with a novel amino acid ligand, L-citrulline. Though there are many reports on the bioimaging applications of nanostructured semiconductors, the present study focused on the detection of a special type of metal accumulating bacteria, Lysinibacillus fusiformis. This bacterium has significant applications in the disposal of metal components from industrial effluents. In this context, the detection of this bacterium is quite important and the present work demonstrates a novel technique for this bacterial detection. The synthesized nanocrystals were attached to Lysinibacillus fusiformis and characteristics of the bioconjugated system were studied. The blue shift observed in the ultraviolet-visible absorption and photoluminescence spectra of the bioconjugated system, confirms conjugation of the Lysinibacillus fusiformis with L-citrulline-capped ZnS:Mn. When the bioconjugated system (capped ZnS:Mn + bacteria) was observed using a fluorescent microscope under excitation wavelengths 365.4 nm (ultraviolet), 435.8 nm (blue) and 546.1 nm (green), fluorescence emissions were obtained in yellow, green and red regions respectively. The study of relative growth of Lysinibacillus fusiformis in the presence of L-citrulline-capped ZnS:Mn proves biocompatible property of these nanocrystals and their tunable color properties under different excitation wavelengths make them ideal for biolabeling applications.

Relative growth, morphological sexual maturity, and size of Macrobrachium amazonicum (Heller 1862) (Crustacea, Decapoda, Palaemonidae) in a population with an entirely freshwater life cycle

The objective of this study was to estimate the size of morphological sexual maturity based on the study of relative growth, to determine the maximum size of individuals, and to determine if there are different morphotypes of males in a population of Macrobrachium amazonicum with an entirely freshwater life cycle. Collections were made monthly, with the use of a net, from September 2006 through August 2007. In each individual, the following structures were measured: carapace length (CL, in mm), width of the second pleuron (PlL, mm), length of the carpus (CaL, mm), and length of the propodus (PrL, mm). Relative growth was analyzed by observing the change in growth patterns of certain parts of the body in relation to the independent variable CL. The maximum sizes found were 8.5 and 11.4 mm CL for males and females, respectively. The morphometric variables: length of the carpus (CL × CaL) for males, and width of the second pleuron (CL × PlL) for females gave the best estimates for the size at maturation, which was 4.26 mm CL for males and 5.39 mm CL for females. The growth pattern in the different stages and the beginning of differential growth seemed to be closely related to reproductive aspects. No indices were found that separated the males into four different morphotypes, as proposed in the literature for coastal or artificially farmed populations. Only the male morphotype termed translucent claw was found in this population. The different morphological patterns in different regions are probably explained by ecological differences in the environments inhabited by these groups, principally in the availability of nutrients and the salinity in which the larvae develop.

Relative Growth and Its Use to Determine the Morphological Sexual Maturity of Ucides Cordatus (Linnaeus, 1763) (Decapoda, Brachyura, Ucididae) from Two Mangrove Areas on the Northeastern Brazilian Coast

AbstractThe study of relative growth was used to determine the dimensions that best demonstrate the morphological sexual maturity of Ucides cordatus from two mangrove areas (Ariquindá and Mamucabas) of the southern coast of the state of Pernambuco, northeast Brazil. The crabs were collected manually, with a capture effort by one person, during low tide in three different areas (each 25 m2) during a period of one year from April 2008 to March 2009. Crabs of both sexes were measured for the following dimensions: carapace width (CW); carapace length (CL); major cheliped propodus length (CPL); major cheliped propodus height (CPH); abdomen width (AW) and gonopod length (GL). These variables were subjected to an analysis of K-means clustering followed by a bivariate discriminant analysis, which separated the data into two groups: juveniles and adults. After separation of the groups, each age category was grouped into sixteen size classes of CW and the proportion of adults in each size class was calculated, and fitted to a logistic equation. Subsequently, an interpolation was performed to determine the size at which 50% of the males and females were mature. The relationships that best demonstrated the size at maturity were CPL vs. CW for males (Positive allometry; Ariquindá — juveniles b = 1.27, adults b = 1.41; Mamucabas — juveniles b =1.27, adults b = 1.44) and AW vs. CW for females (Positive allometry; Ariquindá — juveniles b = 1.34, adults b = 1.28; Mamucabas — juveniles b = 1.32, adults b = 1.44). The present analysis indicates that, for these same relationships, 50% of males and females are morphologically mature, at, respectively, 38.0 and 35.4 mm CW in Ariquindá, and 37.3 and 32.9 mm CW in Mamucabas. Positive allometry shown in the female abdomen is related to egg incubation, and the excessive growth observed in the male cheliped must be related to reproductive behaviour, including courtship and intra- or inter-specific agonistic interactions with other males.

Post-larval morphology, growth, and development of Uca cumulanta Crane, 1943 (Crustacea, Decapoda, Ocypodidae) under laboratory conditions

Studies on the post-larval morphology and growth of crabs can allow correct identification of their early life stages, supporting studies on phylogenetic relationships and ecological aspects. Nevertheless, little is known about the juvenile morphology of ocypodoid crabs worldwide. Uca cumulanta Crane, 1943 is a fiddler crab commonly found in the intertidal zone of the tropical and subtropical western Atlantic. This study describes the morphology of the first juvenile stage of U. cumulanta, its absolute and relative growth, and the appearance and development of its secondary sexual characters. The antennules of U. cumulanta show morphological peculiarities and could probably be used as a distinguishing feature for crabs of this genus. The maxillule and the maxilla have sets of setae forming specialised structures for sorting particles from the sediment. The absolute growth pattern differed statistically between sexes. The study of relative growth revealed differences in the relationships cheliped propodus length (CPL), cheliped propodus height (CPH), and abdomen width (AW) vs. carapace length (CL). These differences between sexes showed that males diverge from females (in the chelipeds) from 3.04±0.11 mm (VI juvenile stage), and females diverge from males (in the abdomen) from 3.84±0.13 mm (VII juvenile stage). The pleopods, rudimentary in the first stage, disappear in the second stage, and then arise in different numbers for each sex from the third juvenile stage on. The spoon-tipped setae found on the second maxilliped, which are used to sort food particles, are evident only from the fourth juvenile stage and increase linearly with carapace growth. The absence of these setae may be the reason why juveniles settle on organic-rich substrates where they can obtain food.

An experimental study of growth in relation to morphology and shoot water content in maritime Antarctic mosses.

The dependence of shoot growth and growth form on water availability was studied experimentally in six species of maritime Antarctic moss. Under all conditions the largest growth increments were observed in the hydric species Brachythecium austro-salebrosum and Drepanocladus uncinatus. The xeric Andreaea depressinervis grew the least. Lateral shoot production varied within and between species. Over 50 % of the biomass produced in D. uncinatus was derived from lateral shoot production, whereas Polytrichum alpestre produced very few lateral shoots and A. depressinervis produced none. Leaf density and leaf size also varied with total water content. In all species growth ceased at total water contents of 100% d. wt or less. However, the total water content at which maximum growth was observed differed between species. Racomitrium austro-georgicum (mesic/xeric) had the lowest optimum for growth at 370% of d. wt and D. uncinatus (hydric) exhibited maximum growth between 890 and 2300% d. wt. Optimum total water contents for growth were greater than those at full turgor and published optima for net assimilation. Growth and total water content of these Antarctic mosses were similar to those reported for temperate species.

BRANCH AND STEM CANKERS OF WHITE AND NORWAY SPRUCES IN ONTARIO

A branch and stem canker disease of white and Norway spruce was investigated in southern Ontario. The disease was found to be associated with the occurrence of Valsa Kunzei var. picea, a wound parasite commonly occurring on spruce in central and eastern United States and Canada. A study of tree growth in relation to the development of stem cankers revealed that stem-cankered trees had been predisposed to the attack, as indicated by a sudden decrease in diameter growth one or more years in advance of the infection.The predisposing factor is believed to be drought, which weakens trees with a poorly developed root system, thus causing the reduced diameter growth and permitting fungus infection of the main stem and the later developmnet of stem cankers.Spruce grown on sites with a continuous supply of aerated soil water will not be affected by the disease if crowding of trees in the stand is avoided.

Relative growth of organs and tissues in mammals.

IN the study of relative growth of organs and tissues, there are certain advantages in referring the relative weights to age, throughout the life-cycle. When results are expressed according to the allometric formula1–3, y = bx α (x = weight of animal, y = weight of organ, b and α=constants), time as an independent variable tends to be eliminated. When, however, the relative weights are expressed in relation to age or its logarithm, they are found to show maximal values at definite periods of the life-cycle, specific for and characteristic of each organ4. The curves of the relative weights, as functions of the logarithm of age, tend to follow one of the types in Fig. 1. Thus, in the rabbit, that of the brain follows, from the nineteenth day of embryonic life until adult age, curve 1 of Fig. 1, that of the liver and of the lungs, curve 2, with maximal values respectively at the twenty-fourth and at the twenty-seventh day of embryonic life; that of the kidneys, curve 3, with a maximum between the second and fourth weeks after birth; that of the stomach, curve 4, with a maximum between the fifth and tenth weeks; that of the muscles, curve 5, with a maximum after puberty; and that of the perirenal adipose tissue seems to follow curve 6 with maximal values only late in the adult age. The same sequence of organs, ranged according to periods of maximal relative weights, is likely to be found in other mammals, as is seen from observations of C. M. Jackson5 on human brain, liver, lungs and kidneys the relative weights of which are maximal in the second, at the end of the third, in the fourth and between the seventh and eighth months respectively.

都市學童の相對育に關する統計的研究 (第1報)

都市學童の相對育に關する統計的研究 (第1報)

Rapid Growth-Rate and Diminishing Heterogony

A STUDY of relative growth in the pistol-crab, Alpheus dentipes1, has disclosed an interesting modification of the simple heterogony law, as expressed by the relation y = bxk, where y and x are magnitudes of organ and body respectively, and b and k are constants, k representing the coefficient of growth-partition between organ and body2.

A study of relative growth in UCA pugnax.

1. 50 males and 43 females were divided into classes according to carapace breadth. The relative growth rates of certain parts of the body were investigated by analysis of linear measurements carried out on the carapace and appendages. 2. The increased growth rate of pereiopods immediately posterior to the strongly heterogonic cheliped was concluded to be due, in part at all events, to the rapid growth of the cheliped, since the increase is considerably smaller on the small cheliped side in the male. 3. There seems to be, in addition, a sexual difference, the growth in the corresponding pereiopods in the female differing from that found in the male on the small cheliped side. 4. In the female the growth of the last two pereiopods is greater than that in the male; it is suggested that this is possibly due to the influence of the region of rapid growth present in the abdomen in the female. 5. The appendages anterior to the large cheliped in the male are apparently not inhibited. In this respect Uca pugnax differs from other forms which have been investigated. 6. The growth rate of the carapace breadth is greater than that of its length throughout the period investigated in the male, but only throughout the earlier part of the development of the female.