Population structure and reproduction of the seagrass shrimp Hippolyte zostericola (Decapoda: Hippolytidae) at Laguna de Términos, Campeche, Mexico

2012 ◽  
Vol 93 (3) ◽  
pp. 675-682
Author(s):  
J. Romero-Rodríguez ◽  
R. Román-Contreras
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Carapace Length ◽  
Female Size ◽  
Size At Maturity ◽  
Seagrass Meadows ◽  
The Mean ◽  
Laguna De Terminos ◽  
The Relationship ◽  
Internal Margin

The aim of this paper is to describe the population structure and some reproductive aspects of Hippolyte zostericola during an annual cycle. Samples were taken bimonthly, from June 2009 to April 2010, with a Colman–Seagrove sledge net on seagrass meadows located in the internal margin of Isla del Carmen, Campeche, Mexico. The population structure of H. zostericola was similar throughout the cycle analysed. The males, significantly smaller than females (0.57–1.8 and 0.55–3.52 mm carapace length (CL), respectively), were more frequent between 0.8 and 1.54 mm CL, whereas in larger size-classes (1.8–3.52 mm CL) only females were registered, ovigerous principally. The sex-ratio was always in favour of males, mean of 1.3 males per female. Size at maturity (CL50) was 2.28 ± 0.1 mm CL. Based on the presence of ovigerous females throughout the year it is considered that the reproduction of H. zostericola is continuous. The main breeding season and recruitment occurs during the first third of the year. The mean fecundity of the species was 144 ± 69 eggs and varies with female size. The higher egg loss occurred in larger females (37.3%) and the relationship between fecundity and female size was estimated as negative allometric, which suggests that age influences the fecundity of the species.

scholarly journals Population structure and life history of Neomysis nigra Nakazawa, 1910 (Mysida) on Jeju Island, South Korea

Crustaceana ◽  
2016 ◽  
Vol 89 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Jae-Yong Bae ◽  
Gyeong Eon Noh ◽  
Won-Gyu Park
Keyword(s):  
Population Structure ◽  
Life History ◽  
South Korea ◽  
Carapace Length ◽  
Developmental Stages ◽  
Jeju Island ◽  
Female Size ◽  
Life Stages ◽  
History Of ◽  
The Mean

Population structure and life history of the mysid Neomysis nigra Nakazawa, 1910 were studied on Jeju Island, South Korea. N. nigra was collected monthly from a shallow embayment of Jeju Island from May 2013 to May 2014. Temperature and salinity were measured during the sampling. The carapace length (CL) of N. nigra was measured. Life stages were divided into six categories and embryos in the marsupium were classified by developmental stages. During the study period, water temperatures ranged from −0.3 to 35.7°C. The CL of females was larger than that of males. The mean CL of adults was negatively correlated with water temperature. CL values in winter and spring were higher than those in summer and autumn. Brooding females and juveniles were found all year round. The abundance of juveniles was relatively higher in May, July, December, and February than in other months. The number of embryos in the marsupium increased with increasing female size. In conclusion, the present study suggests that the populations of N. nigra have four major spawning groups in a year and reproduce all year round.

scholarly journals Abundance and population structure of Plesionika narval (Fabricius, 1787) in the Northeastern Atlantic

2019 ◽  
Vol 79 (1) ◽  
pp. 111-119 ◽  
Author(s):  
R. Sousa ◽  
M. R. Pinho ◽  
J. Delgado ◽  
A. R. Pinto ◽  
M. Biscoito ◽  
...  
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Carapace Length ◽  
Late Summer ◽  
Shallow Waters ◽  
Female Size ◽  
Depth Range ◽  
Madeira Archipelago ◽  
Seasonal Migrations ◽  
Northeastern Atlantic

Abstract Analysis of abundance and population structure of Plesionika narval was performed on data concerning 5,255 specimens obtained from 62 fishing sets carried out off the Madeira archipelago (Northeastern Atlantic) between 2004 and 2008 in a depth range from 101 to 350 m. Abundance ranged from 0.01 to 19.74 specimens-per-trap and significant differences were found between seasons, probably as a result of an increment of population in the spring during the recruitment season. The analysis of size distribution revealed that the carapace length (CL) ranged from 2.45 to 28.61 mm and that mean female size consistently exceeded that of males. Differences in mean CL were statistically significant between depth strata and seasons. Of the specimens sampled, 57.00% were males, 41.88% females and 1.42% undetermined. Sex ratio also differed significantly between seasons according to depth strata, consolidating the hypothesis of the existence of seasonal migrations related with the reproductive cycle of this species. Ovigerous females showed larger sizes and occurred all year around and remain in shallow waters in winter, summer and autumn and move to deeper waters in spring. The highest frequency of ovigerous females was recorded in summer, between 151 and 200 m deep supporting the hypothesis that spawning of this species occurs in shallow waters, especially in late summer.

Panulirus echinatus population in the Brazilian oceanic ecosystem Rocas Atoll

Crustaceana ◽  
2019 ◽  
Vol 92 (2) ◽  
pp. 221-232 ◽  
Author(s):  
Juliana Gaeta ◽  
Raúl Cruz
Keyword(s):  
Sex Ratio ◽  
Carapace Length ◽  
Reproduction Period ◽  
Males And Females ◽  
The Mean ◽  
Oceanic Ecosystem ◽  
Abundant Population ◽  
Future Information

Abstract In Rocas Atoll (03°51′S 033°48′W) a most abundant population of Panulirus echinatus Smith, 1869 was observed during free dives. Numbers of males and females were almost the same, with an overall sex ratio M : F = 1.1. In addition, males are larger than females, with a mean male carapace length (CL) of 92.6 ± 1.8 mm, while the female mean CL was 72.7 ± 1.0 mm and for both sex combined the mean CL was 83.1 ± 1.4 mm. The percentage of females breeding, i.e., with a spermatophore mass or eggs, was 75.1%. More information is needed to better understand the fluctuation in densities over a year cycle, the reproduction period, and differences in CL between males and females, as well as other aspects of the biology of this species. The present work and future information could help to formulate fisheries policies aimed at protecting P. echinatus stocks.

scholarly journals Population Structure and Reproductive Biology of the Endangered Crab Deiratonotus japonicus (Brachyura, Camptandriidae) Surveyed for Nine Years in the Kita River, Japan

2020 ◽  
Vol 8 (11) ◽  
pp. 921
Author(s):  
Il-Kweun Oh ◽  
Seung-Woo Lee
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Carapace Width ◽  
River Mouth ◽  
Sampling Period ◽  
Sampling Station ◽  
Egg Number ◽  
Kanagawa Prefecture ◽  
The Mean

Deiratonotus japonicus (D. japonicus) is known as a near-threatened species, because of the changing conditions of its habitat. This species resides in isolated locations and in upstream, brackish waters from Kanagawa Prefecture to Okinawa Prefecture in Japan. In this study, we investigated the population structure and reproductive biology of D. japonicus in the Kita River, Japan. The distribution, sex ratio, breeding season, and fecundity were assessed at bimonthly intervals during spring low-tide periods from May 2001 to November 2008 and from November 2014 to January 2016 for approximately nine years. A total of 3525 crabs were collected during the sampling period: 1806 (51.2%) males, 1240 (35.2%) non-ovigerous females, and 479 (13.6%) ovigerous females. The overall sex ratio (1:0.95) did not differ significantly from the expected 1:1 ratio. The mean maximum density was 26.1 and 36.5 indiv./m2 for the first and second sampling periods, respectively, in the sampling station 5.2 km from the Kita River mouth, and all individuals were typically found approximately 4.4–6.8 km (13.2 ± 7.8 indiv./m2) from the Kita River mouth. Carapace width (CW) ranged from 2.6 to 13.5 mm in males and from 2.8 to 13.4 mm in females and was significantly different between the two sexes (p < 0.05). Ovigerous females were found almost throughout the entire sampling period, with breeding peaks between July and September. The smallest ovigerous female had a CW of 3.9 mm. The seasonal frequency distribution suggested the continuous recruitment of young juveniles (CW < 3.9 mm) throughout the year, with peaks from September to November. The mean fecundity was 1008.3 ± 183.1 (8.3 ± 1.6 mm) eggs. Egg number in relation to CW was calculated by the formula egg number (EN) = 110.36 × CW + 90.96 (R2 = 0.948, n = 41, p < 0.0001). Regression analysis showed that fecundity was closely associated with female CW. Our results indicate that the performance of reproductive biology depends not only on continuous breeding but also on recruitment throughout the year in our study area.

scholarly journals On the fecundity and sex-ratio of Botia Dario (Hamilton) (Cypriniformes : Cobitidae)

1970 ◽  
Vol 26 ◽  
pp. 27-29 ◽  
Author(s):  
M Afzal Hussain ◽  
Mst Rehana Khatun ◽  
M Altaf Hossain
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Standard Length ◽  
Female Ratio ◽  
Ovary Weight ◽  
Total Length ◽  
Length Standard ◽  
The Mean ◽  
The Relationship ◽  
Male To Female

A total of 1183 Botia Dario (Hamilton) samples were collected from Rajshahi (Shaheb Bazar, Binodpur Bazar, Talaimari Bazar, Kazla Bazar and Godagari) during the period from January, 2002 to August, 2003 to study the fecundity, sex-ratio, relationship between fecundity and total length, standard length, body weight, ovary length as well as ovary weight. The mean fecundity was calculated as 31833.50±10313.42 with a range of 5245 to 53754 in fishes ranging in total length from 96 mm to 135 mm (mean 115.50±12.11 mm) and in body weight from 14.51 g to 43.29 g (mean 29.71±6.91 g). The relationship between the fecundity (F) and total length (TL), standard length (SL), body weight (BW), ovary length (OL) and ovary weight (OW) were found to be linear with the ‘r’ values 0.94, 0.94, 0.95, 0.92 and 0.98, respectively. The ovum diameter ranged from 0.3 to 0.72 mm and the mean diameter was calculated as 0.518±0.06 mm. The male to female ratio was 1:0.61. Key words: Botia dario, fecundity, sex-ratio. Univ. j. zool. Rajshahi Univ. Vol. 26, 2007. pp. 27-29

scholarly journals On the Fecundity and Sex-ratio of Labeo bata (Hamilton) (Cypriniformes: Cyprinidae)

2015 ◽  
Vol 11 (2) ◽  
pp. 43-48
Author(s):  
MAR Joadder
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Average Length ◽  
Total Body Weight ◽  
Total Length ◽  
Labeo Bata ◽  
The Mean ◽  
Total Body ◽  
Gravid Females ◽  
The Relationship

The fecundity and sex- ratio of 2200 Labeo bata (Hamilton) specimens were studied. The fecundity of 234 gravid females varied from 51,354( for a fish with total length of 127.3 mm and total body weight of 20.0 g) to 91,568( for a fish with total length of 256.6 mm and total body weight of 156.70g).The mean fecundity was recorded as 67,617.50±13,510.15 for the average length and weight of 192.98±41.06 mm and 87.79±49.07 g, respectively .The mean total length and weight of gonad was 67.62± 24.01 mm and 20.35±13.50 g, respectively .The relationship between fecundity ( F.) and other parameters such as total length ( TL ), Standard length ( SL),  total weight( TW),  gonadal length (GL),  gonadal weight (GW) and gonadal depth (GD) were studied. DOI: http://dx.doi.org/10.3329/jsf.v11i2.21595 Journal of Science Foundation, 2013;11(2):43-48

Population structure of Emys orbicularis in the Bardello (Po Delta, Northern Italy)

1995 ◽  
Vol 16 (1) ◽  
pp. 77-85 ◽  
Author(s):  
Stefano Mazzotti
Keyword(s):  
Population Structure ◽  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Population Size ◽  
Carapace Length ◽  
Shell Height ◽  
Northern Italy ◽  
Emys Orbicularis ◽  
Frequency Distributions ◽  
Po Delta

AbstractA population of Emys orbicularis in the Bardello (Po Delta, Northern Italy) was studied for 3 years using capture-mark-recapture methods, 23.6% of which were male, 57,5% female and 18.9% were juvenile specimens. The sex ratio of 127 specimens was 1:2. Certain morphometric variables such as the carapace length and shell height were examined in order to establish their sexual dimorphism. The population structure was defined by means of frequency distributions of carapace length. Using the Lincoln-Petersen and Jolly-Seber indices it was possible to estimate the population size as an average of 7.2 specimens per hectare.

scholarly journals Population structure of Macrobrachium amazonicum (Heller, 1862) (Decapoda: Palaemonidae) in Miranda Hydroelectric Plant Reservoir, Araguari river, Minas Gerais, Brazil

2019 ◽  
Vol 31 ◽  
Author(s):  
Raquel Costa e Silva ◽  
Marina Calixto Cunha ◽  
Emerson Contreira Mossolin ◽  
Giuliano Buzá Jacobucci
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Carapace Length ◽  
Hydroelectric Plant ◽  
Size Variation ◽  
Minas Gerais ◽  
Size Class ◽  
Size Frequency Distribution ◽  
Reproduction Strategy ◽  
Continuous Reproduction

Abstract Aim The present study aimed to analyze a M. amazonicum population structure in a reservoir of the “Triângulo Mineiro”, Brazil. Methods Monthly surveys were carried out from April/2012 to May/2013 at the Miranda Hydroelectric Plant Reservoir located in Araguari river, state of Minas Gerais. A sampling section of 100 m long, 5 m wide and depth not exceeding 1 m was defined on the banks of the reservoir. Sampling consisted on two persons quickly passing a 2 mm sieves in partially submerged marginal vegetation, for one hour. The sampled specimens were identified, sexed and measured. Results A total of 2,584 specimens were analyzed, of which 64.62% were females (3.93% ovigerous, 5.94% non-ovigerous and 54.75% juveniles), 29.16% males (21.41% adults and 7.76% juveniles) and 6.22% juveniles of undetermined sex. The sex ratio (1:2.21) indicated a clear deviation for females, for the whole sampling period, monthly and for each size class. Males had an average carapace length (CL = 4.50 ± 0.71 mm) significantly lower than females (CL = 4.64 ± 1.47 mm) and the size frequency distribution revealed a unimodal pattern, with peaks occurring in 4.0 - 4.9 mm size class for males and in 3.0 - 3.9 mm size class for females. The relation between total and carapace length was significant, indicating a negative allometric growth. No males’ morphotypes were found. The population presented a continuous reproduction with a gradual increase between April and June/2012. Female sexual maturity was determined for 6.3 mm of CL, while for males was estimated for 4.0 mm. Conclusion The Miranda reservoir population had a body size variation similar to the continental populations of Pantanal. The sexual dimorphism observed may be related to the absence of male morphotypes and to the “pure search” reproduction strategy. The deviated sex ratio for females may increase the chance of fertilization and the reproductive success. The presence of juveniles and ovigerous females throughout the year indicates a continuous reproduction pattern of the population.

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

1991 ◽  
Vol 65 (03) ◽  
pp. 263-267 ◽  
Author(s):  
A M H P van den Besselaar ◽  
R M Bertina
Keyword(s):  
Reference Material ◽  
Standard Error ◽  
Standard Errors ◽  
Sensitivity Index ◽  
Long Term Stability ◽  
Significant Bias ◽  
The Mean ◽  
The Relationship ◽  
International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Fecundity and Gonado-somatic Index of Trichiurus lepturus (Linnaeus, 1758) Along the Zamboanga del Norte Coast

2018 ◽  
Vol 6 (7) ◽  
pp. 120
Author(s):  
Ma. Dulce C. Guillena
Keyword(s):  
Sex Ratio ◽  
Stock Assessment ◽  
Chi Square ◽  
Moon Phases ◽  
Ovary Weight ◽  
Moment Coefficient ◽  
Trichiurus Lepturus ◽  
Significant Difference ◽  
The Relationship ◽  
Somatic Index

Gonado-somatic index and fecundity are tools for measuring the sexual maturity and ability of animals to reproduce.  This study investigates the reproduction of Trichiurus lepturus. Specifically, this aimed to determine the sex ratio, the GSI, the relationship between fecundity and total length, fecundity and total weight, fecundity and ovary weight. The Descriptive Method of research was used.  Percentage and chi-square was utilized in determining the percentage of occurrence and sex ratio respectively.   Pearson r Product Moment Coefficient of Correlation was used to determine the relationships of the parameters. The study revealed that females outnumbered males and the sex ratio for different month showed significant difference.  Spawning season was observed to occur in November and December as revealed in its GSI values and it synchronized with the full and new moon phases.  Fecundity is positively correlated with body weight, body size, and ovary weight where ovary weight is observed to be the best index for fecundity.  The results of this study could be used further for formal stock assessment of cutlassfish fishery.

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