scholarly journals Reproductive biology of Poecilia sphenops Valenciennes, 1846 (Cyprinidontiformes: Poeciliidae) at the Emiliano Zapata Reservoir in Morelos, Mexico

2016 ◽  
Vol 14 (2) ◽  
Author(s):  
José L. Gómez-Márquez ◽  
Bertha Peña-Mendoza ◽  
José L. Guzmán-Santiago

ABSTRACT Poecilia sphenops is a native species recently recorded in the Balsas basin and the Amacuzac River in Morelos (Mexico), in which it is abundant and widely distributed. This study analyzed some aspects of the reproductive biology of Poecilia sphenops from the Emiliano Zapata Reservoir, in Central Mexico. Specimens were collected using a 20 m-long seine with a 5 mm mesh size, from January to December 2006. A total of 581 specimens were collected: 407 females (70.0%), 83 males (14.3%) and 91 individuals with no differentiated sex (15.7%). Fish ranged from 20 to 96 mm in total length and 0.01 to 13.07 g in body weight. The female to male sex ratio (4.9:1) deviated significantly from the unity (χ2= 214.2, p<0.05). Monthly variations in gonadosomatic (GSI) and hepatosomatic (HSI) indexes and ovarian development stages showed that P. sphenops spawning season occurred between July and October, concurring with the rainy season. Another reproduction peak was registered in February. The largest length registered for males and females was 96 mm and 83 mm, respectively.

2018 ◽  
pp. 1801-1812
Author(s):  
José Luis Gómez-Márquez ◽  
Bertha Peña-Mendoza ◽  
Isaías H. Salgado-Ugarte ◽  
Abby K. Sánchez-Herrera ◽  
Leonardo Sastré-Baez

A reproductive analysis of 1 225 specimens of Poeciliopsis gracilis obtained through monthly samples from Coatetelco, a tropical shallow lake in Central Mexico, was made. There was an evident sexual dimorphism, including a difference in body size at the onset of reproduction. Sex ratio deviated significantly from unity. Monthly variations in gonadosomatic (GSI), hepatosomatic (HSI) indexes and ovarian development stages showed that the spawning season was from July to October, coinciding with the rainy season and phytoplankton biomass increase.


2009 ◽  
Vol 7 (4) ◽  
pp. 745-750 ◽  
Author(s):  
Augusto B. C. Vieira ◽  
Luiz F. Salvador-Jr. ◽  
Rafael M. C. Melo ◽  
Gilmar B. Santos ◽  
Nilo Bazzoli

To analyze the reproductive biology of the peacock bass Cichla piquiti, 361 specimens were collected bimonthly in the Itumbiara Reservoir, southeast Brazil, from December 2004 to November 2005. Males and females in reproductive activity occurred during almost the entire year, with reproductive peak occurring before the beginning of the rains when the water temperature remained low, indicating that these environmental variables do not directly influence in the reproduction of C. piquiti. The long reproductive period, partially spent ovaries contained postovulatory follicles and oocytes in all developmental stages, indicate asynchronous development of oocytes and multiple spawning. The mean total lengthand body weigth were, respectively, 38.2 ± 7 cm and 965.0 ± 654.0 g for males and 37.4 ± 6.1 cm and 899.0 ± 495.0 g for females, statistically showing no sexual dimorphism in size. The smallest male and female found in advanced maturation stage measured 31.0 cm and 29.0 cm of total length, respectively. The body condition (K) of males and females did not present significant differences during the reproductive cycle and the slope (b) of the length-weight relationship was 3.22, suggesting that reproduction and the annual hydrology cycle do not interfere in the health condition. Cichla piquiti is an exotic piscivore fish that is well adapted to this Neotropical reservoir, which exhibits environmental conditions considerably different from its original habitat. This study indicates that the species presents plasticity in reproduction and in allocation of resources, probably due the aseasonality of the reservoir and the exploitation of native species.


1972 ◽  
Vol 29 (7) ◽  
pp. 1079-1081
Author(s):  
J. I. Manzer

The length–weight relationship for 298 pomfret (Brama japonica) ranging in fork length from 30 to 49 cm, and caught in 1956 and 1957 in the Gulf of Alaska by gillnets varying in mesh size from [Formula: see text] (63 mm) to [Formula: see text] inches (133 mm) was examined. Covariance analysis of the data indicated that within years the length–weight relationship did not differ between males and females; and, on the average, both males and females of a particular length were significantly heavier in 1956 than in 1957. Allometric equations for each year based on data for sexes combined are considered more appropriate than a single equation based on pooled data. The equations relating weight in kilograms to length in centimeters, for 1956 and 1957, respectively, are[Formula: see text]and apply to the lower third of the known size range for pomfret in the Gulf of Alaska.


Author(s):  
Nitin Kanji Suyani ◽  
Mridula Rajesh ◽  
Kothanahally Mallegowda Rajesh

Abstract The feeding habits and reproductive biology of red-toothed triggerfish Odonus niger (Ruppell, 1836) was analysed from 449 specimens collected from the Karnataka coast of the south-eastern Arabian Sea. Of the total stomachs examined, only 54 (12%) were empty and 395 contained food remains. The diet comprised crustacean remains (48.0%), zooplankton (21.4%), algae (16.5%), fish remains (6.1%) and cephalopod remains (5.3%) along with partially digested matter (2.3%) and detritus (0.4%). The species was found to be a generalist feeder and an omnivore. The overall sex ratio between males and females (1: 0.44) was significantly (P < 0.05) different. Histological examination of the ovaries indicated asynchronous ovarian development in females, with males maturing earlier than females. The gonadosomatic index (GSI) patterns of males and females, and the presence of ripe ovaries and spermatozoids suggested that April–May is the peak spawning period. The absolute and relative fecundity estimates ranged from 16,464–312,420 eggs and 251–2812 eggs g−1 respectively. Fecundity was positively correlated with total length and body weight. The biological information on diet composition and reproductive traits provided for the first time in this study can facilitate conservation, management and sustainable exploitation of this species in the study area.


Author(s):  
Daniel Enrique Rodriguez Bauza ◽  
Patricia Silveyra

Exercise-induced bronchoconstriction (EIB) is a common complication of athletes and individuals who exercise regularly. It is estimated that about 90% of patients with underlying asthma (a sexually dimorphic disease) experience EIB; however, sex differences in EIB have not been studied extensively. With the goal of better understanding the prevalence of EIB in males and females, and because atopy has been reported to occur at higher rates in athletes, in this study, we investigated sex differences in EIB and atopy in athletes. A systematic literature review identified 60 studies evaluating EIB and/or atopy in post-pubertal adult athletes (n = 7501). Collectively, these studies reported: (1) a 23% prevalence of EIB in athletes; (2) a higher prevalence of atopy in male vs. female athletes; (3) a higher prevalence of atopy in athletes with EIB; (4) a significantly higher rate of atopic EIB in male vs. female athletes. Our analysis indicates that the physiological changes that occur during exercise may differentially affect male and female athletes, and suggest an interaction between male sex, exercise, and atopic status in the course of EIB. Understanding these sex differences is important to provide personalized management plans to athletes with underlying asthma and/or atopy.


2002 ◽  
Vol 23 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Otavio Marques ◽  
Lígia Pizzatto

AbstractThe reproductive biology of the false coral snake, Oxyrhopus guibei, was studied through dissection of 496 specimens, combined with observations on captive individuals. Males mature with smaller body size than females, females attain much larger body size, and male-male combat is not expected. Clutch size ranged from 3 to 20, and was correlated with female length. Reproductive cycles in both males and females seem to be continuous, with vitellogenesis and spermatogenesis occurring throughout the year. Reproductive activity in both sexes decreased at the end of the rainy season possibly due to previous intense reproductive activity in more favorable climatic conditions. The smaller number of individuals collected at the end of the rainy season apparently occurs due to the decrease of reproductive activity of this snake.


2017 ◽  
Vol 34 (1) ◽  
pp. 81-90 ◽  
Author(s):  
A. Ramírez-García ◽  
J. P. Ramírez-Herrejón ◽  
M. Medina-Nava ◽  
R. Hernández-Morales ◽  
O. Domínguez-Domínguez

Behaviour ◽  
2015 ◽  
Vol 152 (2) ◽  
pp. 127-146 ◽  
Author(s):  
Pauline M. Capelle ◽  
Erin S. McCallum ◽  
Sigal Balshine

Invasion biology research has identified two juxtaposing behavioural traits, aggressiveness and sociality, that may both increase the success of species invasions. Highly aggressive invaders can out-compete native species for resources, while social gregarious invaders can tolerate high conspecific density. In order to tease apart the effects of aggressive versus social tendencies on the success of invasive species, we studied round goby (Neogobius melanostomus), a highly successful invasive fish species now common in the Laurentian Great Lakes. While round goby are well known for being aggressive, much less is known about their tendency to affiliate with conspecifics, in spite of the fact that they thrive in extremely high densities in many of their invaded habitats. We collected round goby from Hamilton Harbour, ON, Canada and conducted three separate experiments to explore group-forming behaviour by measuring preference for conspecifics. We found that round goby have a strong preference to associate with a single conspecific, and that both males and females showed this preference. No overall preference was detected for large versus small groups of conspecifics. Females chose the safety of a shelter over associating with a conspecific but males were equally attracted to conspecifics as shelter. Our results provide new insight into how interactions between aggressive and social behaviours play a role in the rapid spread of invasive round goby.


Author(s):  
Rosana Mazzoni ◽  
Jaqueline Petito

Aspects of the reproductive biology of one Tetragonopterinae was assessed in the Ubatiba river - Maricá / RJ. Length structure and mean size suggested sexual dimorphism, females reaching larger sizes than males. The onset of sexual maturity occured at 2.8cm for both the sexes. Fecundity, determined on ripe ovaries, showed positive correlation to females size and weight and varied from 595 to 5520 for 3.9cm and 6.2cm lengths respectively. The spawning type, defined as total, was determined by the oocyte diameter frequency from ovaries in different development stages. The frequency distribution of ovarian/testis maturation stages, associated with the temporal variation of the gonadosomatic index, suggested that the reproduction period was prolonged along the whole annual cycle.


Zootaxa ◽  
2019 ◽  
Vol 4550 (1) ◽  
pp. 1
Author(s):  
BERNHARD A. HUBER

As part of the Western Ghats-Sri Lanka biodiversity hotspot, Sri Lanka harbors a rich and diverse fauna, especially in the perhumid southwestern part of the island. However, many invertebrate groups such as spiders continue to be poorly studied. The present paper reviews our knowledge about Pholcidae, a family of spiders that is well represented in Sri Lanka, both by numerous (10) introduced species and by a rich native fauna in five genera (described native Sri Lankan species in parentheses): Belisana Thorell, 1898 (6), Leptopholcus Simon, 1893 (1), Pholcus Walckenaer, 1805 (4), Tissahamia Huber, 2018 (4), and Wanniyala Huber & Benjamin, 2005 (9). Fourteen species are newly described: Belisana minneriya sp. n., B. badulla sp. n., B. gowindahela sp. n.; Pholcus metta sp. n., P. puranappui sp. n., P. uva sp. n.; Tissahamia karuna sp. n.; Wanniyala mudita sp. n., W. orientalis sp. n., W. upekkha sp. n., W. ohiya sp. n., W. viharekele sp. n., W. mapalena sp. n., and W. labugama sp. n.. All new species are described from males and females. New Sri Lankan records are given for 16 previously described species. Distribution data suggest that most or all of the 24 native species might be endemic to Sri Lanka, but the Indian pholcid fauna remains almost entirely unknown. 


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