scholarly journals Iheringichthys labrosus (Siluriformes: Pimelodidae) in the Piquiri River, Paraná, Brazil: population structure and some aspects of its reproductive biology

2009 ◽  
Vol 7 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Arlei J. Holzbach ◽  
Éder A. Gubiani ◽  
Gilmar Baumgartner
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Standard Length ◽  
Length Distribution ◽  
Temporal Distribution ◽  
Spatial And Temporal Distribution ◽  
Night Time ◽  
Reproduction Period ◽  
Iheringichthys Labrosus

The purpose of this study was to analyze the population structure (spatial and temporal distribution, sex ratio, length distribution and length/weight relationship) and reproductive biology of Iheringichthys labrosus. This species is of importance as fisheries resource in the Paraná River basin. Fish were sampled, bimonthly, with gill and trammel nets at three sampling sites (Campina, Apertado and Altônia), located in the Piquiri River, between November 2002 and September 2003. In this study, 164 individuals were collected; the largest capture occurred in Campina site, with 209.88 individuals/1000 m² of net for 24 hours, while the shift of largest capture was night time (N) and the month was July. Females occurred in larger numbers than males in all periods. The growth was allometric positive and the reproduction period was from the beginning of September to the end of December, with the majority of the individuals showing a standard length between 13.0 and 20.0 cm.

Some aspects of reproductive biology of Gobius paganellus (Gobiidae) on the north-eastern coasts of Tunisia (Bizerta lagoon)

2013 ◽  
Vol 93 (8) ◽  
pp. 2235-2246 ◽  
Author(s):  
Ibtissem Louiz ◽  
Mossadok Ben Attia ◽  
Oum Kalthoum Ben Hassine
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Gonadosomatic Index ◽  
Length Distribution ◽  
Sexual Cycle ◽  
Hepatosomatic Index ◽  
Gobiid Fish ◽  
Spawning Period ◽  
North East ◽  
Bizerta Lagoon

The rock goby, Gobius paganellus one of the most common gobiid fish in Bizerta lagoon (north-east of Tunisia), is a gonochoric species that belongs to the Gobiidae family. This study provides the first detailed information of its reproductive biology in lagoon environments. Gobius paganellus was sampled monthly from January 2005 to December 2006 involving 1486 specimens. Total length distribution ranged between 38 and 125 mm. The maximum recorded total lengths were, respectively, 122 mm and 125 mm for female and male. Over the entire population, the sex-ratio was unbalanced in favour of females. According to months, a predominance of females sex-ratio was recorded during the spawning period while according to body size, males were dominating among larger size-classes. In both sexes, the variation of the gonadosomatic index (GSI) was independent of size. Macroscopic and microscopic examination of the gonads added to the monthly monitoring of gonadosomatic index and hepatosomatic index showed that gonads development begins in October and spawning period extends from December to March. The cyclic pattern of gonads development was determined by histology. Results indicated that G. paganellus exhibits a group-synchronous oocyte development. The sizes of first sexual maturity related to 50% of mature individuals were 78.3 mm (CI95: 77–84 mm) for males and 79 mm (CI95: 75–85 mms) for females. The discussion part underlined the impacts of some environmental factors and antropization of this lagoon on sexual cycle of G. paganellus.

scholarly journals Population structure and reproductive biology of Astyanax gymnodontus (Characiformes: Characidae), a poorly known endemic fish of the Iguaçu River basin, Brazil

2016 ◽  
Vol 64 (1) ◽  
pp. 69 ◽  
Author(s):  
Matheus Tenorio Baumgartner ◽  
Pedro Rogério Leandro da Silva ◽  
Gilmar Baumgartner
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
River Basin ◽  
Reproductive Biology ◽  
Body Length ◽  
Fish Species ◽  
Energy Allocation ◽  
Influence Area ◽  
Endemic Fish ◽  
Iguaçu River

Success in fish breeding depends on reproduction intensity, periodicity and the place where it occurs. Information about fish species reproduction is important to assist managers, and to determine conservation and management strategies. The fish assemblage of the Iguaçu River basin is already known for its high endemism, and despite this privilege, the large number of dams built along it, threat this particular biodiversity. Astyanax gymnodontus is an endemic fish species and studies on its population structure and reproductive biology are important, since they represent the first step for further community studies. Our objective was to evaluate some aspects of the population structure and reproductive biology of A. gymnodontus in the influence area of Salto Santiago dam, Iguaçu River, Paraná State, Brazil. Sampling was made monthly from July 2003 to June 2005, and bimonthly from July 2005 to March 2013, at five sites in the influence area of Salto Santiago dam. Fishes were collected using 10 m length gillnets with meshes ranging from 2.5 to 6.0 cm between non-adjacent knots and trammel nets with inner meshes of 6.0 cm between non-adjacent knots. Nets were arranged on surface, bottom and margins of each site, exposed for 24 h. Additional drags on littoral areas were performed from January to March and October to December from 2009 to 2011, with 50.0 m nets, 0.5 cm mesh size, for juveniles capture. We captured and analyzed 21 932 individuals, being 9 249 females and 12 683 males, representing 42.2 % and 57.8 %, respectively. The average body length was 8.8 cm for females and 8.3 cm for males. The average weight was 18.8 g for females and 16.0 g for males. Sex ratio calculated for the entire period was 1.8 males/female. Males were more abundant than females in 73.2 % of samples and significant differences were observed in 35.3 % of samples. The estimated length at first maturity (SL50) was 6.4 cm for females and 6.2 cm for males. We suggest that sexual differences in body length and weight, and sex ratio occurred as a result of sexual differences in energy allocation. Females spend more energy on body growth, which means more eggs production and higher fecundity. As an integrated response, males spend more energy on sperm production, in competition with other males, leading to a smaller body size. Differences in estimated SL50 might be an indicator of this sexual difference in energy allocation. The reproduction period was from September to February, with greater intensity at the beginning of this period, and the sites of highest reproductive intensity were those immediate downstream from dams, and therefore with more riverine characteristics.

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 Population structure, condition and diet of Oligosarcus paranensis (Menezes & Gery, 1983) (Osteichthyes: Characidae) at two reservoirs in South Brazil

2012 ◽  
Vol 12 (1) ◽  
pp. 187-197 ◽  
Author(s):  
Milza Celi Fedatto Abelha ◽  
Elaine Antoniassi Luiz Kashiwaqui ◽  
Erivelto Goulart
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Standard Length ◽  
Volumetric Method ◽  
Population Parameters ◽  
Allometric Growth ◽  
Structure Condition ◽  
Food Items ◽  
Plant Matter ◽  
South Brazil

This study investigated the population parameters, condition and diet of Oligosarcus paranensis at Fiú and Mourão Reservoirs, located in Paraná State, Brazil. The fishes were collected quarterly between 1996/1997 and 1998/1999 using gillnets. Food items were quantified by volumetric method. The specimens at Fiú showed comparatively smaller length and worse condition. Sex ratio was statistically equal to 1:1 at Mourão, whereas there was a significant predominance of males at Fiú. Sex ratio also varied among size classes. Allometric growth prevailed among the studied groups. The diet consisted mainly of fishes and was complemented with invertebrates and plant matter in both reservoirs. There was a change in the feeding pattern as the standard length increased. Fishes changed from invertivores to piscivores, except for males in Mourão, for which a reverse trend occurred.

scholarly journals Reproduction De Heterotis Niloticus (Cuvier, 1829) De La Riviere Agneby (Cote d’Ivoire)

2016 ◽  
Vol 12 (6) ◽  
pp. 83 ◽  
Author(s):  
Kouakou Fokouo Kessia Irène ◽  
Koné Tiéhoua ◽  
Soro Yaya ◽  
N’Da Konan ◽  
Ouattara Mamadou
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Standard Length ◽  
Sexual Maturity ◽  
Condition Factor ◽  
Artisanal Fishing ◽  
Relative Fecundity ◽  
Maturation Stages ◽  
Liver Somatic Index ◽  
Somatic Index

The reproductive biology of Heterotis niloticus has been studied from monthly samples taken from artisanal fishing on the Agneby river during the period june 2013 to May 2015. The whole sample consisted of 498 specimens of which 269 females and 229 males were examined. Sex-ratio observed was in favour of females (1: 1.17; X2 = 3.21; p > 0.05). The monthly evolution of the gonado-somatic index (GSI), the liver-somatic index (LSI), the condition factor (K) and maturation stages suggests that this fish has two periods of reproduction. The two periods were respectively from june to august and from november to december. The standard length at first sexual maturity was 490.6 mm for females and 436.3 mm for males. The absolute fecundity was ranged from 5424 to 25591 oocytes in females of 595 mm to 780 mm standard length. The relative fecundity was 3752± 1491 oocytes/kg of female.

scholarly journals Reproduction of Hypoptopoma inexspectatum (Holmberg, 1893) (Siluriformes, Loricariidae) in the Southern Pantanal Floodplain, Upper Paraguay River Basin, Brazil

2020 ◽  
Author(s):  
M. J. Pereira ◽  
L. F. Viana ◽  
M. H. B. Sais ◽  
Y. R. Súarez
Keyword(s):  
Sex Ratio ◽  
River Basin ◽  
Reproductive Biology ◽  
Standard Length ◽  
Relative Fecundity ◽  
Absolute Fecundity ◽  
Weight Relationship ◽  
Paraguay River

Abstract This work aimed to describe the reproductive biology of Hypoptopoma inexspectatum in southern Pantanal. A total of 538 individuals were sampled and analyzed from February 2009 through January 2011 in southern Pantanal. We did not observe differences in sex-ratio, and both sexes presented positive allometric length/weight relationship (LWR). Reproduction occurs mainly from January to February. Females reached first maturation (L50) with 37.80 mm and males with 45.80 mm. Absolute fecundity is estimated in mean=177.43 (sd±127.06) oocytes and relative fecundity in 3.12 (sd±2.23) oocytes/mg. Fecundity is positively correlated with standard length (Spearman r= 0.43; p=0.013), and total spawning is a used spawning strategy for H. inexspectatum.

Reproductive characteristics of the sand sole Pegusa lascaris (Soleidae), from the eastern-central Atlantic

2008 ◽  
Vol 88 (3) ◽  
pp. 629-635 ◽  
Author(s):  
José G. Pajuelo ◽  
José M. Lorenzo
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Standard Length ◽  
Spawning Season ◽  
Significant Difference ◽  
Males And Females ◽  
First Maturity ◽  
Central Atlantic ◽  
Size At First Maturity

The reproductive biology of 1318 sand sole, Pegusa lascaris, was investigated. This species is a gonochoristic species with no evidence of sexual dimorphism. The overall sex-ratio was 1 male to 0.92 females. Females predominate in the larger size intervals, with a significant difference in mean standard length and range between sexes. Size at first maturity for males and females is attained at 17.2 and 17.7 cm standard length, respectively. Vitellogenesis does not begin synchronously for all females, as a consequence the spawning season appears to be continuous. In each female spawning takes place in two batches which are spawned mainly in spring and autumn, indicating that fish are serial synchronous spawners.

scholarly journals Some aspects of the reproductive biology and sex-ratio of Cirrhina reba (Hamilton) (Cyprinidae : Cypriniformes)

2012 ◽  
Vol 30 ◽  
pp. 21-24
Author(s):  
Sarmin Akther ◽  
Shirin Akther
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Standard Length ◽  
Total Weight ◽  
Chi Square ◽  
Male And Female ◽  
Total Length ◽  
Chi Square Test ◽  
Somatic Index

Some aspects of the reproductive biology viz. sex-ratio gonadal length index (G.L.I.), gonado somatic index (G.S.I.) and sex-ratio of Cirrhina reba were studied during September 2004 to July 2005. In present study the highest values of GLI (33.76) and GSI (0.63) were in the month of July. Total length (TL) and gonadal length (GL), total weight (TW) and gonadal weight ( GW ), standard length (SL) and gonadal length ( GL ) and gonadal weight relationships were found to be positive; and the relationships were: GL = -3.873 + 0.219 TL (r = 0.992), GW = 0.01511+0.000815 TL (r = 0.979), GL = -2.6030+0.253 SL (r = 0.990), GL = 0.01997+0.000938 SL (r= 0.976), GW = 13.2952+0.6064 TW (r = 0.958), GW = 0.0772+0.00233 TW (r = 0.979). The sex- ratio of C. reba were 1:1.62 for male and female respectively. The Chi-square test showed significant differences of sex-ratio among months and totals.DOI: http://dx.doi.org/10.3329/ujzru.v30i0.10739Univ. j. zool. Rajshahi Univ. Vol. 30, 2011 pp. 21-24

scholarly journals Population structure and reproductive biology of Loricariichthys melanocheilus Reis & Pereira, 2000 (Siluriformes: Loricariidae) in the rio Ibicuí, Brazil

2015 ◽  
Vol 13 (2) ◽  
pp. 371-382 ◽  
Author(s):  
Éverton Luís Zardo ◽  
Everton Rodolfo Behr
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Maturity Stage ◽  
Allometric Growth ◽  
Males And Females ◽  
Lotic Environments ◽  
Gonadal Condition

The objective of this study was to analyze population structure (spatial distribution, seasonal distribution and distribution by length classes, sex ratio and length-weight relationship) and aspects of the reproductive biology of Loricariichthys melanocheilus. Fish were sampled bimonthly using gillnets and trammel nets in lentic and lotic environments in the rio Ibicuí, between the years 2000 and 2001. Were collected 410 specimens: 230 females, 164 males and 16 specimens whose sex could not be determined. A greater number of specimens were collected in October/November and December/January and in lentic environments. The greater length classes had a higher amount of females (p < 0.05) and the sex ratio in all sampling periods was 1.38 females per male. Both males and females showed positive allometric growth (b = 3.299 and b =3.487, respectively). The highest values for gonadosomatic index (GSI) and gonadal condition factor (K) were observed from August/September and peaked in October/November, just like the highest frequencies of females at maturity stage C (mature), which is indicative that the breeding season occurs at this time.

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