Negative Allometric Relationship Research Articles

Length–Weight Relationships of Commercial Species in the Eastern Australian Sea Cucumber Fishery

Biological data, such as length–weight relationships, are essential for the management and stewardship of harvested individuals. Sea cucumbers are a lucrative industry globally but many of the associated fisheries lack species-level biological data, which reduces the effectiveness of any management strategy. The Queensland Sea Cucumber Fishery (QSCF) on the Great Barrier Reef is managed through various controls: primarily catch limits, effort limits, zoning, and size restrictions. Over 20 species may be harvested but there is a lack of comprehensive biological data for many of these species, particularly important life history characteristics. This study addresses this knowledge gap by assessing 2621 individual length–weight relationships of key-target sea cucumber species associated with the fishery across the range of the distribution of the species and covering a variety of habitats, depths, sampling times, and management zones. Linear models with log transformations were used to analyse the relationships between length and weight. Results revealed significant positive relationships for all assessed species, with Holothuria atra having the clearest relationship between length and weight (R2 = 0.45). Only negative allometric relationships were observed, as is the case for many species of holothurians. Despite challenges associated with measuring and weighing these soft and elastic animals, results will be useful for understanding length–weight dynamics across species. This research underscores the importance of robust biological data for the effective management of sea cucumber fisheries and ultimately reef health.

The "Leafing Intensity Premium" Hypothesis and the Scaling Relationships of the Functional Traits of Bamboo Species.

The "leafing intensity premium" hypothesis proposes that leaf size results from natural selection acting on different leafing intensities, i.e., the number of leaves per unit shoot volume or mass. The scaling relationships among various above-ground functional traits in the context of this hypothesis are important for understanding plant growth and ecology. Yet, they have not been sufficiently studied. In this study, we selected four bamboo species of the genus Indocalamus Nakai and measured the total leaf fresh mass per culm, total non-leaf above-ground fresh mass, total number of leaves per culm, and above-ground culm height of 90 culms from each species. These data were used to calculate leafing intensity (i.e., the total number of leaves per culm divided by the total non-leaf above-ground fresh mass) and mean leaf fresh mass per culm (i.e., the total leaf fresh mass per culm divided by the total number of leaves per culm). Reduced major axis regression protocols were then used to determine the scaling relationships among the various above-ground functional traits and leafing intensity. Among the four species, three exhibited an isometric (one-to-one) relationship between the total leaf fresh mass per culm and the total non-leaf above-ground fresh mass, whereas one species (Indocalamus pumilus) exhibited an allometric (not one-to-one) relationship. A negative isometric relationship was found between the mean leaf fresh mass per culm and the leafing intensity for one species (Indocalamus pedalis), whereas three negative allometric relationships between mean leaf fresh mass per culm and leafing intensity were observed for the other three species and the pooled data. An exploration of the alternative definitions of "leafing intensity" showed that the total number of leaves per culm divided by the above-ground culm height is superior because it facilitates the non-destructive calculation of leafing intensity for Indocalamus species. These results not only confirm the leafing intensity premium hypothesis for bamboo species but also highlight the interconnected scaling relationships among different functional traits, thereby contributing to our understanding of the ecological and evolutionary significance of leaf size variation and biomass investment strategies.

Evaluating the muscle attachment hypothesis for sagittal cresting in Gorilla and Pongo.

Primate mandibular morphology is often associated with jaw functionality of the masticatory complex in the context of variation in diets. Recent research into the disparities between the diet and jaw functionality in male and female hominoids is inconclusive and suggests that sexual dimorphism in the mandible may be influenced by external factors such as temporalis and masseter muscle morphology, which in turn may be influenced by sexual selection. As the muscles associated with mastication (i.e., the type of chewing exhibited by primates and other mammals) encompass the mandible as well as the neurocranium, including the sagittal crest among some individuals, this study investigates sex-specific associations between regions of the mandibular ramus and neurocranium associated with mastication in a dentally mature sample of Gorilla and Pongo. A total of four cranial and mandibular variables were measured in two Gorilla taxa (Gorilla gorilla gorilla and Gorilla beringei graueri) and one Pongo taxon (Pongo pygmaeus pygmaeus) (n = 220). For all three taxa, we investigate (a) whether the degree of sexual dimorphism in cranial regions associated with sagittal cresting (sagittal crest size (SCS) and temporalis muscle attachment area (TMAA)) is proportional to the degree of mandibular ramus area (MRA) and coronoid process height (CPH) sexual dimorphism, (b) whether there are sex differences in scaling relationships between TMAA and MRA, and (c) whether there are sex differences in the strength of association between TMAA and CPH. We show that for G. g. gorilla, variables associated with sagittal cresting show higher sexual dimorphism values than our two mandibular ramus variables, which is not the case for G. b. graueri or for P. p. pygmaeus. All three taxa show similar sex-specific scaling relationships between TMAA and MRA, where for males this relationship does not diverge from isometry, and for females there is a negative allometric relationship. Our findings also show intraspecific sex differences in allometric slopes between MRA and TMAA for all three taxa. Only G. g. gorilla shows a significant association between TMAA and CPH, which is observed in both sexes. Although there are some statistical associations between the cranial and mandibular regions associated with mastication, our results show that among male gorillas and orangutans, patterns of variation in the sagittal crest, TMAA, mandibular ramus and the coronoid process cannot be explained by the muscle attachment hypothesis alone. These findings have implications surrounding the associations between social behaviour and the morphology of the craniofacial complex.

Influence of wastewater treatment on the reproduction and growth of Mytilus galloprovincialis in Agadir's central Atlantic marine ecosystem, South Morocco

Mytilus galloprovincialis is common in Morocco's Anza-Taghazout coast, previously polluted by wastewater. Since treatment plants were installed in 2016, no study examined the mussels' reproduction. Our study assessed how wastewater treatment affects the reproduction and growth of the M. galloprovincialis mussel on Moroccan coasts, particularly in the Anza-Taghazout area. We aimed to clarify the impacts of treated effluents on this vital invertebrate. This research explored their reproductive parameters, with samples taken from 2017 to 2018 at Anza, Aourir, and Imouran. Results show all gametic stages with three spawning periods. The gonadal index exceeds 1.4 at all sites, indicating a short resting phase. The sex ratio is balanced in Aourir and Imouran, but Anza has more males. The length-weight relationship showed the b value of 1.56 (R2 = 0.32); 1.71 (R2 = 0.35), and 1.70 (R2 = 0.26) for Anza, Aourir, and Imouran respectively. This suggests a slight negative allometric relationship. The condition index showed a progressive trend, and M. galloprovincialis improved due to enhanced environmental quality after treatment.

The More the Merrier or the Fewer the Better Fare? Effects of Stand Density on Tree Growth and Climatic Response in a Scots Pine Plantation

In forests, the growth and productivity of individual trees and stands as a whole are regulated by stand density among other factors, because access to vital resources is limited by competition between trees. On 18 experimental plots of Scots pine (Pinus sylvestris L.) planted with a density of 500–128,000 trees/ha in the south taiga (Middle Siberia), interactions between stand density, tree- and stand-scale productivity, and tree-ring parameters were investigated. Tree-scale productivity variables, tree-ring width, and latewood width had stable negative allometric relationships with stand density (R2 > 0.75), except for tree height (insignificant for inventory surveys at ages of 20 and 25 years; R2 > 0.4 at the age of 35 years), while positive allometry was registered for stand productivity variables (R2 > 0.7) and the all-time average latewood ratio (R2 = 0.5 with planting density). Tree-ring parameters aside from the age trends correlate (p < 0.05) between the plots and demonstrate common responses to moderate moisture deficit. Although, its seasonality apparently depends on the resource base and intensity changes with stand density. February–June precipitation is more important for pine growth in dense stands, July–August conditions affect the latewood ratio stronger in sparse stands, and medium-density stands are more resistant to winter frosts.

Differences Between the Allometric Rules Governing Two Formica lugubris Zetterstedt, 1838 (Hymenoptera: Formicidae) Ants Populations in Northern Greece

Red wood ant workers, despite being monomorphic, show a wide range in their body size even within the same colony. As overall size grows, some organs grow in a negative allometric relationship with the body. Genetic and environmental factors, like diet and temperature, are considered as key factors that determine differences in body and organ growth. We studied the allometric rules governing the organs in two different populations of red wood ants in two different environments in Northern Greece to identify similarities and differences. These rules, although linear for both populations and negative allometric for most of the traits measured, differ in the two study areas, while the shape of the head found to be governed by different allometric rules between the two populations. The whole shape and size of red wood ants varies greatly even within the same species and we cannot create allometric models for two different areas, even when they belong in the same species. The differences might be a result of differences in the genome and the environmental conditions between the two populations.

武夷山不同海拔毛竹细根功能性状

PDF HTML阅读 XML下载 导出引用 引用提醒 武夷山不同海拔毛竹细根功能性状 DOI: 10.5846/stxb202112143536 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（32071555）；福建省科技厅产学合作项目（2019N5009）；福建省教育厅项目（JAT190084） Fine root traits of Phyllostachys edulis at different altitudes in Wuyi Mountain Author: Affiliation: Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:细根作为植物最重要的资源获取功能器官，是影响陆地生态系统的重要组成部分。定量化毛竹的细根功能性状对于理解其生理生态特征响应及生活史策略至关重要。为揭示毛竹细根功能性状随海拔梯度的变化规律以及细根的适应策略，对武夷山不同海拔（840 m、1040 m、1240 m）毛竹细根的碳（C）、氮（N）、磷（P）含量和比根长（SRL）、比根面积（SRA）等性状进行测定，分析细根性状在海拔上的差异及其异速生长关系。结果表明：（1）不同海拔毛竹细根养分性状存在显著差异。毛竹细根C含量在海拔1040 m最大。随海拔升高，细根N、P含量均呈下降趋势，细根C ： N、C ： P随着海拔的升高而增加。（2）细根的结构性状在海拔梯度上差异显著。随海拔升高，细根平均根直径（AvgDiam）、SRL及SRA均呈下降趋势，而根组织密度（RTD）呈升高趋势。（3）细根性状间存在显著的异速生长关系。细根N与P含量存在显著的等速生长关系，二者与C含量存在显著异速生长关系；SRL与SRA存在显著的等速生长关系，二者与RTD存在显著的负等速生长关系，与N含量存在显著的异速生长关系；细根AvgDiam与RTD存在显著的负异速生长关系。毛竹细根功能性状海拔梯度差异显著且细根性状之间呈显著的异速生长关系，表明毛竹细根获取型性状（如SRL）与保守型性状（如RTD）存在权衡，在海拔840 m毛竹倾向于增加根长来获取养分和水分，随海拔升高则采取保守策略，如增加根组织密度。因此，毛竹能够通过自身表型可塑性机制合理权衡细根性状之间的资源配置以适应环境变化。 Abstract:As the most important resource-obtaining functional organ of plants, fine roots are an important part affecting terrestrial ecosystems. Quantifying the fine root functional traits of Phyllostachys edulis is critical to our understanding of the physiological response and ecological characteristics for bamboo's life-history strategies. To investigate the variation of fine root traits of Phyllostachys edulis with altitude gradient and the adaptation strategies of fine roots, the contents of carbon (C), nitrogen (N), phosphorus (P), specific root length (SRL), specific root area (SRA) and other traits of Ph.edulis's fine roots were measured in Wuyi Mountain at different altitudes (840 m, 1040 m, 1240 m), and the differences of fine root traits at different altitudes and the allometric relationship between them were analyzed. The results showed that:(1) there were significant differences in the contents of C, N, P and the ecological stoichiometry among different altitudes. The content of C in fine roots was the highest at the altitude of 1040 m, with the increase in altitude, the content of N and P decreased, leading to the increase of the ratio of C:N and C:P. (2) There were significant differences on the structural traits of fine roots among different altitudes. As the altitude increased, the average root diameter (AvgDiam), SRL, SRA of fine roots all showed a downward trend, while the root tissue density (RTD) showed an upward trend. (3) There was a significant allometric relationship between fine root traits. The significant isometric relationships were found between N and P content in fine roots, but they showed a significant allometric relationship between C content. There was a significant isometric relationship between SRL and SRA, but they showed a significantly negative isometric relationship with RTD, and showed a significant allometric relationship with N content. The significantly negative allometric relationships were found between AvgDiam and RTD. There was a significant difference of fine root functional traits among different altitudes, and a significant allometric relationship between them. Our research showed that there was a trade-off between fine root acquisitive traits (such as SRL) and conservative traits (such as RTD). Ph.edulis tended to increase root length for increasing nutrient absorption at altitude of 840 m, and adopted the conservative strategy (such as increasing root tissue density) with increasing altitude. Therefore, Ph.edulis can rationally balance resource allocation among fine root traits to adapt to environmental changes through phenotypic plasticity mechanism. 参考文献 相似文献 引证文献

Allometry of behavior and niche differentiation among congeneric African antelopes

AbstractSize‐structured differences in resource use stabilize species coexistence in animal communities, but what behavioral mechanisms underpin these niche differences? Behavior is constrained by morphological and physiological traits that scale allometrically with body size, yet the degree to which behaviors exhibit allometric scaling remains unclear; empirical datasets often encompass broad variation in environmental context and phylogenetic history, which complicates the detection and interpretation of scaling relationships between size and behavior. We studied the movement and foraging behaviors of three sympatric, congeneric spiral‐horned antelope species (Tragelaphusspp.) that differ in body mass—bushbuck (26–40 kg), nyala (57–83 kg), and kudu (80–142 kg)—in an African savanna ecosystem where (i) food was patchily distributed due to ecosystem engineering by fungus‐farming termites and (ii) predation risk was low due to the extirpation of several large carnivores. Because foraging behavior is directly linked to traits that scale allometrically with size (e.g., metabolic rate, locomotion), we hypothesized that habitat use and diet selection would likewise exhibit nonlinear scaling relationships. All three antelope species selected habitat near termitaria, which are hotspots of abundant, high‐quality forage. Experimental removal of forage from termite mounds sharply reduced use of those mounds by bushbuck, confirming that habitat selection was resource driven. Strength of selection for termite mounds scaled negatively and nonlinearly with body mass, as did recursion (frequency with which individuals revisited locations), whereas home‐range area and mean step length scaled positively and nonlinearly with body mass. All species disproportionately ate mound‐associated plant taxa; nonetheless, forage selectivity and dietary composition, richness, and quality all differed among species, reflecting the partitioning of shared food resources. Dietary protein exhibited the theoretically predicted negative allometric relationship with body mass, whereas digestible‐energy content scaled positively. Our results demonstrate cryptic size‐based separation along spatial and dietary niche axes—despite superficial similarities among species—consistent with the idea that body‐size differentiation is driven by selection for divergent resource‐acquisition strategies, which in turn underpin coexistence. Foraging and space‐use behaviors were nonlinearly related to body mass, supporting the hypothesis that behavior scales allometrically with size. However, explaining the variable functional forms of these relationships is a challenge for future research.

Genetic identity and length-weight relationships of Indo-Pacific sergeant Abudefduf vaigiensis (Quoy and Gaimard, 1825) from the south-east coast of India

Ambiguity regarding the identification of Indo-Pacific sergeant Abudefduf vaigiensis (Quoy and Gaimard, 1825) was sought out through classical taxonomic approach along with molecular confirmation. DNA barcoding of 650 bp region of the Cytochrome C oxidase 1 gene revealed the confirmation of taxonomical identity of the species from the region. Length-weight relationships and relative condition factor in A. vaigiensis were investigated on the samples collected from the south-east coast of India, Gulf of Mannar, to assess the significance of allometric factor and the wellbeing. A total of 360 fishes were collected for the study and categorised into four groups namely males, females , fishes with morphologically undifferentiated gonads (unsexed) and overall pooled samples. Among 360 fishes, 154 were males and 88 were females and the remaining 118 were categorised as unsexed. The analysis was based on fish samples with total length (TL) ranging from 83 to 150 mm and weighing 12.5 to 62.5 g. Length-weight equation and regression coefficient obtained for males, females, unsexed and pooled fishes were W = 0.06 L2.55 (R2 = 0.82); W = 0.02 L2.94 (R2 = 0.88); W = 0.04 L2.68 (R2 = 0.96) and W = 0.04 L2.67 (R2 = 0.92) respectively. The regression parameter ‘b’ obtained in all the cases were below 3, indicating negative allometric relationship of length and weight. Relative condition factor (K) among pooled fishes showed a value above 1, which indicates better condition of fish. The results of the present study showed that the existing hydrobiological conditions of the Gulf of Mannar area were conducive for food availability, free movement, feeding and better growth of the fish. The present study is also the first report on the molecular confirmation of the species from Indian waters and its morphometry from south-east coast of IndiaKeywords: COI sequencing, Indo-Pacific sergeant major, Length-weight relationship, Relative condition factor, South-east coast of India

Population Characteristics of the Upper Infralittoral Sea Urchin Arbacia lixula (Linnaeus, 1758) in Eastern Mediterranean (Central Greece): An Indicator Species for Coastal Water Quality

The black sea urchin (Arbacia lixula, Linnaeus, 1758) is a non-edible marine echinoderm of high ecological importance with the potential to affect marine ecological communities. A. lixula were sampled monthly for one year from the supralittoral fringe at two locations in the Pagasitikos Gulf, in the north-western Aegean Sea. Morphometric characteristics exhibited significant spatiotemporal variation. The population in closer proximity to treated sewage effluent outflow exhibited significantly higher biometric relationships resulting in possible improved physiological conditions. Spatial distribution exhibited a clumped pattern of dispersion, consisting of predominantly six age classes. The dominant cohort was the four-year age class, comprising 31.2% of the total population. Significant negative allometric relationships were exhibited between all morphometric characteristics. The maximum approximate age of the total A. lixula population was estimated at 15.27 years. The von Bertalanffy growth equation for the entire population was estimated as: test diameter = 62.881×1−e−0.196×Age+1.147. The gonadosomatic index indicated a seasonal cycle with a peak in late spring. The approximate age of sexual maturity was estimated at 4.45 years. We observed a significantly higher number of females than expected at the site in closer proximity to the treated sewage effluents (32% of total female number).

Morphometric characteristics of four important fish species from the Rwandan side of Lake Kivu

Inland fisheries are important socio-economic resources for rural communities in Africa. In Rwanda, about two million people directly depend on capture fisheries from Lake Kivu. Sustainable fisheries management requires monitoring of population dynamics that help devise effective intervention strategies. However, the relevant data such as length-length and length-weight relationships do not exist for most of the key species in Lake Kivu. The present study generated morphometric and body weight data for Limnothrissa miodon (n=82), Lamprichthys tanganicanus (n=55), Haplochromis vittatus (n=51) and Haplochromis graueri (n=34) from Lake Kivu. Length-weight relationships (W=aLb) were highly significant for all species (p < 0.0001), high adjusted R2 = 78 to 98% of the variance in weight explained by total length. Negative allometric length-weight relationships were found with regression slope (b) values of 2.7 for Limnothrissa miodon, 2.8 for H. graueri, and 2.8 for L. tanganicanus, and positive (b=3.4) for Haplochromis vittatus. Length-length relationships were highly significant for all species (p ≤ 0.0001), except for the relationship between total and caudal length for L. miodon, and total and caudal peduncle length for L. tanganicanus, both not significant at p > 0.05. The highest R2 was for the relationships between total and standard length for H. vittatus, and total and fork length for L. tanganicanus. No description of length-length relationships exists for these species in literature or in FishBase database. The data generated in the current study will be used to assess changes in fish populations over time.

The distribution, number, and certain neurochemical identities of infracortical white matter neurons in the brains of a southern lesser galago, a black-capped squirrel monkey, and a crested macaque.

In the current study, we examined the number, distribution, and aspects of the neurochemical identities of infracortical white matter neurons, also termed white matter interstitial cells (WMICs), in the brains of a southern lesser galago (Galago moholi), a black-capped squirrel monkey (Saimiri boliviensis boliviensis), and a crested macaque (Macaca nigra). Staining for neuronal nuclear marker (NeuN) revealed WMICs throughout the infracortical white matter, these cells being most dense close to inner cortical border, decreasing in density with depth in the white matter. Stereological analysis of NeuN-immunopositive cells revealed estimates of approximately 1.1, 10.8, and 37.7 million WMICs within the infracortical white matter of the galago, squirrel monkey, and crested macaque, respectively. The total numbers of WMICs form a distinct negative allometric relationship with brain mass and white matter volume when examined in a larger sample of primates where similar measures have been obtained. In all three primates studied, the highest densities of WMICs were in the white matter of the frontal lobe, with the occipital lobe having the lowest. Immunostaining revealed significant subpopulations of WMICs containing neuronal nitric oxide synthase (nNOS) and calretinin, with very few WMICs containing parvalbumin, and none containing calbindin. The nNOS and calretinin immunopositive WMICs represent approximately 21% of the total WMIC population; however, variances in the proportions of these neurochemical phenotypes were noted. Our results indicate that both the squirrel monkey and crested macaque might be informative animal models for the study of WMICs in neurodegenerative and psychiatric disorders in humans.

Faktor Kondisi dan Pola Pertumbuhan Oxygaster anomalura

This study aims to obtain information related to the biological and ecological aspects of the Oxygaster anomalura in the Mailil River, Bandar Kumbul Village. The method used in this research is exploratory. Sampling was done using a fishing rod. The growth pattern was calculated using the length-weight relationship using the Linear Allometric Model (LAM), while the condition factor used the Fulton formula (K) and relative weight (Wr). The results showed that as many as 30 samples of Sulum Fish (Oxygaster anomalura) were caught during the study. Analysis of the length-weight relationship showed a negative allometric relationship with a value of b=1.94 (b>3). The Fulton condition factor (K) value is 1,195, while the value of the relative condition factor (Wr) is 169.42. In conclusion, the Mailil River as an ecosystem and habitat for O. anomalura fish is balanced.
 Keywords: Condition Factor, Oxygaster anomalura, Mailil River

Bioecological aspect of lamasi (Barbonymus gonionotus) in mailil rever labuhanbatu district, indonesia

The existence of gold mining activities in mailil river can disrupt the stability of the ecosystem, fishing by using toxins, which may result in a decrease in fish populations in the river mailil. This study aims to obtain information related to biological and ecological aspects (Barbonymus gonionotus) in river Mailil, Village. This study was conducted from November 2020 to January 2021. The locations for sampling were determined based on information from the local community in Bandar Kumbul Village. Samples were caught using nets, traps, and nets Sampling was conducted from 09:00 am to 03:00 pm. The biological aspect being measured was the length-weight relationship of the fish using the linear allometric model (LAM). Meanwhile, the ecological aspect being measured was the condition factor using Fulton’s K equation and relative weight (Wr) equation. In this study, 54 silver barbs (B. gonionotus) were successfully caught as samples. The results of the length-weight relationship analysis indicated a negative allometric relationship with the value of b = 0.52 (b < 3). Furthermore, the value of Fulton’s K condition factor was 27.75, while the value of relative weight (Wr) condition factor was 100.07. These results indicated that river Mailil as an ecosystem and habitat of silver barbs is in the balance condition.Keywords: Length-weight relationship, Barbonymus gonionotus, aek mailil

Reproduction of Indian Mackerel Rastreliger kanagurta (Cuvier, 1816) in Morodemak Coast Demak Regency

Indian mackerel is a group of small pelagic fish that has high economic value and is ecologically important. The catch of Indian mackerel in the Morodemak Coastal Fishing Port of Central Java has decreased within 2016-2018, which is suspected by overexploitation. This study aims to observe the reproduction of Indian mackerel. Fish samples were collected from the catches of the mini purse seine operated by fishermen in April-June 2019. The fish samples were measured their length and weight individually, then the abdomen dissected to collect gonad, and counted in sub-sample of the egg number. Data were analyzed to determine the length-weight relationship of fish, sex ratio, gonad maturity level (GML), gonad maturity index (GMI), the size of the first gonad matured, and the egg number in each gonad brood fish. The results showed a negative allometric length relationship, and the length-weight relation equation in female fish was W = 0.038 L 2.59 and in male was W = 0.178 L 2.03. The value of fish condition factors in males, and females obtained values ranging from 1-2. The proportion of fish in GML III ranges from 27.2 to 82.5%, while GML IV ranges from 3.6 to 33.8%. Fish GMI ranged from 0.17 to 4.75%. The eggs number ranged from 11.235 to 40.878 grain. The female Indian mackerel get the first gonad matured at the size of 15.2 cm.

Population Characteristics of the Mid-Littoral Chthamalid Barnacle C. stellatus (Poli, 1791) in Eastern Mediterranean (Central Greece)

Barnacles are key space-occupiers in rocky shore communities on European coasts. Barnacles of the species Chthamalus stellatus (Poli, 1791) were collected between June 2014 and May 2015 from two sites, two stations per each site with varying degree of exposure to wave action and anthropogenic pressure (trampling), in the Eastern Mediterranean (Pagasitikos Gulf, Central Greece). This study addresses a knowledge gap in population characteristics of C. stellatus populations in the Eastern Mediterranean, assessing population structure and allometric relationships. Patterns of distribution and abundance (density and percentage cover) were studied both temporally (seasonally) and spatially (water level and site). Morphometric characteristics exhibited spatiotemporal variation. Population density was significantly higher at the site with higher wave exposure. The population cover exhibited high levels of similarity among shore levels, both spatially and temporally. Spatial distribution exhibited a clumped pattern of dispersion in autumn, winter, and spring, mainly in the sheltered site. Six dominant age groups were identified, with the dominant cohort in the third-year class. Significant negative allometric relationships were exhibited between all morphometric characteristics. Differences in growth patterns among populations were indicated, with a higher rate of growth at the site of lower wave exposure.

Short Communication: Density and length-weight relationship of mudskipper (Periophthalmus spp.) in the mangrove area of Kairatu Beach, Maluku, Indonesia

Abstract. Taniwel D, Leiwakabessy F, Rumahlatu D. 2020. Short Communication: Density and length-weight relationship of mudskipper (Periophthalmus spp.) in the mangrove area of Kairatu Beach, Maluku, Indonesia. Biodiversitas 21: 5465-5473. Mudskippers (genus Periophthalmus) fish species inhabit mudflat, sandy beaches, and mangrove areas. Their daily activities are influenced by tidal rhythms. The aim of this research was to identify the species of mudskipper, their density, and length-weight relationship of more density species in the mangrove area of ​​Kairatu beach, Maluku, Indonesia. This research was conducted from July to August 2018, 3 sampling sites using purposive sampling technique. The physical-chemical parameters of environmental conditions (temperature, dissolved oxygen, salinity, and pH of water) were measured directly on location (in-situ), while the different mudskippers species present in the study sites were identified in the laboratory at the Pattimura University. Quantitative data on population density and length and weight of individuals were obtained for four Periophthalmus species. The physical-chemical parameters of environmental conditions in the three sampling stations were within the range of optimal values previously obtained for mudskipper species. The temperatures ranged from 30.01-30.05 oC, the dissolved oxygen ranged from 7.1-7.5 mg/L, the pH ranged from 7.3-7.5, and the salinity ranged from 5-7 ‰. The four mudskippers species identified in the sampling sites were (in density descending order): Periophthalmus argentilineatus (5.05 ind/m2), P. gracilis (1.5 ind/m2), P. malaccensis (0.4 ind/m2) and P. kalolo (0.3 ind/m2). The results of the regression analysis showed that there was no significant relationship between physical-chemical parameters to mudskipper density. The results of the length-weight relationship of the two most abundant species P. argentilineatus and P. gracilis a negative allometric length-weight relationship (b<3), while the P. kalolo and P. malaccensis indicated a positive allometric growth type (b>3).

Population Characteristics of the Limpet Patella caerulea (Linnaeus, 1758) in Eastern Mediterranean (Central Greece)

Limpets are pivotal for structuring and regulating the ecological balance of littoral communities and are widely collected for human consumption and as fishing bait. Limpets of the species Patella caerulea were collected between April 2016 and April 2017 from two sites, and two samplings per each site with varying degree of exposure to wave action and anthropogenic pressure, in Eastern Mediterranean (Pagasitikos Gulf, Central Greece). This study addresses a knowledge gap on population characteristics of P. caerulea populations in Eastern Mediterranean, assesses population structure, allometric relationships, and reproductive status. Morphometric characteristics exhibited spatio-temporal variation. Population density was significantly higher at the exposed site. Spatial relationship between members of the population exhibited clumped pattern of dispersion during spring. Broadcast spawning of the population occurred during summer. Seven dominant age groups were identified, with the dominant cohort in the third-year class. Significant negative allometric relationships were exhibited between morphometric characteristics. Differences in growth patterns among populations were indicated.

Evaluation of some Essential and Toxic Metals in farmed Ctenopharyngodonidella in relation to Body Size and Condition Factor

Basic aim of this research was to determine levels of some metals (Ca, Cd, Cr, Co, Cu, Fe, K, Mn, Ni, Na, Pb Zn) and their relationships to body size and condition factor in the whole body of Ctenopharyngodon idella (Grass carp). Concentrations of these elements were assessed in 55 fish samples of different size, randomly collected in January, 2015, from a private fish farm by ICP-OES after wet digestion method. Results of the study showed that analyzed elements were found within normal ranges. Ca, Cu, Fe, K, Mn, Na and Zn had highly significant relationships with fish size. Cd, Pb, Cu, K, Mn, Ni, Na, increased isometrically while Cr, Co, Zn, had negative allometric relationship and Fe and Ca showed positive allometric relationship with rise in weight of C. idella. Moreover, Ni, Mn, Pb and Cd represented isometric increase whereas Na, K, Zn, Fe and Ca had positive allometry; and Co, Cu, Cr had negative allometry with increase in total length of the fish. Most of inter-elemental relationships showed. Multiple regressions analyses showed positive correlation for Fe, Cu, Zn, Mn, Pb, Na, K, Ca and Ni had highly significant relations with total length and body weight.

Weight-length relationship, morphometric and meristic characters of the yellow seahorse Hippocampus kuda Bleeker, 1852 (Syngnathiformes: Syngnathidae) from central west coast of India

Eighteen morphometric and five meristic characters of the yellow seahorse, Hippocampus kuda inhabiting the coastal waters of Ratnagiri, central west coast of India, were studied. Morphometric/numerical analysis confirmed the identity of the species from Ratnagiri coastal waters as Hippocampus Kuda Bleeker, 1852. A negative allometric relationship was observed in both genders of H. kuda. The estimated weight-length relationships (WLR) for male and female specimens, respectively were, W=0.0034 SL2.8533 and W=0.0078 SL2.5253 (r2>0.95). The biological information on morphometric and meristic characters, WLR and length-length relationship (LLR) provided in this study would be helpful for conservation and management of this vulnerable seahorse species.