Reproductive cycle of the blue jack mackerel, Trachurus picturatus (Bowdich, 1825), off the Portuguese continental coast

2019 ◽  
Vol 32 ◽  
pp. 14
Author(s):  
Ana Maria Costa
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Condition Factor ◽  
Stock Assessment ◽  
Gonadosomatic Index ◽  
Biological Information ◽  
Hepatosomatic Index ◽  
Jack Mackerel ◽  
First Time ◽  
Monthly Variations

This work provides for the first time a description of the reproductive biology of Trachurus picturatus in Portuguese continental waters (between 41° 49′ and 36° 57′ latitude North). From January 2010 to December 2016 a total of 7409 individuals were sampled from bottom trawlers operating on the northwestern coast of Portugal. The observed sex ratio was 0.56 in favor of the females. Monthly variations in gonadosomatic index, proportion of actively spawning individuals, hepatosomatic index and Fulton′s condition factor were analyzed. More than 60% of spawning individuals were recorded in the first quarter, corresponding to the highest values of GSI, and Fulton's K and hepatosomatic index increased after the start of spawning. The morphometric relationships between total length and gutted weight showed significant correlations (high determination coefficient, r2 > 0.9) and isometric growth (b = 3) for both sexes. Results indicate that the spawning season of T. picturatus starts in December and extends until April–May, with a peak in March, which agrees with what has been indicated by other authors for the northeast Atlantic. This work provides important biological information on a species that although not subject to stock assessment is currently the 5th species landed by weight in Portuguese continental waters.

scholarly journals The length-weight relationship, condition factor and reproductive biology of Pseudotolithus (p) senegalensis (valenciennes, 1833) (croakers), in Tombo western rural district of Sierra Leone

2014 ◽  
Vol 14 (66) ◽  
pp. 9376-9389
Author(s):  
JO Olapade ◽  
◽  
S Tarawallie
Keyword(s):  
Sex Ratio ◽  
Sierra Leone ◽  
Reproductive Biology ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Hepatosomatic Index ◽  
Allometric Growth ◽  
Spawning Period ◽  
Weight Relationship ◽  
Spawning Behaviour

The length – weight relationship (LWR), condition factor (K), sex ratio, gonadosomatic index (G S I) and hepatosomatic index (H S I) of 412 specimens of Pseudotolithu s s enegalensis (Valenciennes, 1833) from Tombo , a coastal fishing community in the western rural district of Sierra Leone were studied for twelve months . Samples used for the study were collected from the catches of artisanal fishers and measurement s of length and weight of samples were done in situ using the facilities of the Ministry of Fisheries and Marine Resources. Samples for the reproductive study were preserved in an ice box and taken to the laboratory of the Department of Aquaculture and Fisheries Management, Njala University , Sierra Leone for analysis. The parameters "a" and "b" of the length - weight relationship were estimated using the equation described by Ricker ( W = aL b ) while the condition factor was calculated using Fulton`s equation (K = W1 00 / L 3 ) . The reproductive biology of the fish was estimated using Gonadosomatic index ( GSI ) and Hepatosomatic index ( H S I ) . The combined LWR for both sexes showed that a, b and r values were – 2.57 , 3. 3 5 and 0. 899 , respectively. The r – values obtained show a strong linear relationship between the length and weight of the species. The length - weight relationship indicated allometric growth for P . senegalensis in the study area. The condition factor (K) varied from 0.64 – 1.0 ; this may be attributed to environmental conditions of the water . The species clearly exhibited a positive allometric growth pattern ( tα ( 2) , 0.05, 411 > 1.965) . The sex ratio of males to females was 1:1. 15 and was not significantly different from the expected 1:1 ratio. Estimation of GSI and HSI was carried out from December, 2010 to May, 2011 to determine the spawning behaviour of P. senegalensis . The mean GSI obtained indicate d that March and April , respectively are the two peak spawning period for the species . Gonado somatic index ranged between 1.1 % and 2.8% for the females. The results of this study revealed that P. senegalensis doe s not have obligatory spawning month but exhibit multiple spawning behaviour. T he length - w eight relationships and condition factor of the study indicated that the fish were thriving very well in the coastal water of Sierra Leone. Sustainable management of the species , therefore , require s that the environment be protected against anthropogenic pollution and imposition of closed fishing season especially during the t wo peak spawning period is recommended to enable the species recruit effectively.

scholarly journals REPRODUCTIVE BIOLOGY OF THE MULLET LIZA FALCIPINNIS (VALENCIENNES, 1836) IN TWO AFRICAN COMPLEXS LAGOONS (EBRIÉ AND GRAND-LAHOU) (CÔTE D’IVOIRE)

2018 ◽  
Vol 6 (5) ◽  
pp. 114-127
Author(s):  
Ebram Luc Gervais ◽  
Soumaïla SYLLA ◽  
Tizié Thierry ZAN-BI ◽  
Boua Célestin ATSE
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Fork Length ◽  
Total Body Weight ◽  
Hepatosomatic Index ◽  
Spawning Period ◽  
Total Body ◽  
Monthly Variations

The reproduction of Liza falcipinnis were investigated in both lagoons (Ebrié and Grand-Lahou) from January 2006 to december 2007. 2162 specimens were examined (914 and 1248 respectively in Ebrié and Grand-Lahou lagoons). Fork length was taken to the nearest 1 mm, and total body weight (TW) and eviscerated body weight (EW) to the nearest 0.1 g. The gonads and the liver were then established removed, weighted to the nearest 0.001g. The reproduced period of Liza falcipinnis was established by analysing the temporal evolution of the frequency of the maturity stages and the monthly variations in the gonadosomatic index (GSI), the hepatosomatic index (HIS) and the condition factor (K). Sex ratio was established taking into account the sex determinations. The size at which 50 % of the specimens became mature (FL50) was estimated. The sex ratio (1:1.24) and (1:1.40) observed respectively in Ebrié and Grand-Lahou lagoons were in favour of females. The first sexual maturity size was 21.0 cm (FL) for males and 27.9 cm (FL) for females in Ebrié lagoon and 24.7 cm (FL) for males and 27.9 cm (FL) for females in Grand-Lahou lagoon. Liza falcipinnis spawns in lagoon and the spawning period ranged from December to April.

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 Some biological characteristics of the smooth blaasop puffer fish Lagocephalus inermis (Temminck and Schlegel, 1850), from south-eastern Arabian Sea

2020 ◽  
Vol 67 (4) ◽  
Author(s):  
Purbali Saha ◽  
Sujitha Thomas
Keyword(s):  
Sex Ratio ◽  
Arabian Sea ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Hepatosomatic Index ◽  
Fishery Resource ◽  
South Eastern ◽  
Significant Difference ◽  
Eastern Arabian Sea ◽  
Puffer Fish

Length-weight relationship (LWR), condition factor, sex ratio, gonadosomatic index (GSI) hepatosomatic index (HSI) of the smooth blaasop puffer fish Lagocephalus inermis (Temminck and Schlegel, 1850), an emerging fishery resource along south-eastern Arabian Sea were studied from 1,722 samples collected during August 2017-May 2019 from Mangalore Fishing Harbour, Karnataka, India. LWR indicated negative allometric growth [W = 0.034805L2.76 (males); W = 0.033574L2.78 (females), W = 0.033979L2.77 (pooled)] and significant difference was observed in the b value of the fishes. Sex ratio was 1:1.08. The ratio was unusually high during post-monsoon and Chi-square test revealed that the monthly sex ratio did not vary significantly throughout the year except for December and January (p<0.01). Condition factor (K) and relative condition factor (Kn ) also were not significantly different between sexes. Two peak spawning seasons were identified - NovemberFebruary and August. The GSI was highest in August (female = 8.08 and male = 5.82) and lowest in May (female = 3.32 and male = 3.49). The HSI value was found to be inversely related to GSI and was highest in May (5.21) and lowest in August (3.99). These parameters are essential pre-requisites for stock assessment and sustainable management of the fishery resource.

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.

scholarly journals Reproductive biology of the Neotropical electric fish Brachyhypopomus draco (Teleostei: Hypopomidae) from southern Brazil

2009 ◽  
Vol 7 (4) ◽  
pp. 737-744 ◽  
Author(s):  
Andrea B. Schaan ◽  
Júlia Giora ◽  
Clarice B. Fialho
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Water Depth ◽  
Electric Fish ◽  
Gonadosomatic Index ◽  
Reproductive Period ◽  
Weakly Electric Fish ◽  
Hepatosomatic Index ◽  
Southern Brazil

The reproductive biology of a population of the weakly electric fish Brachyhypopomus draco from southern Brazil is described. Information is provided on the establishment of the reproductive period in this species and its relations with environmental and feeding factors, as well as on the absolute and relative fecundities, spawning type, sex ratio and sexual dimorphism. The species exhibits a relatively long reproductive period, a relative fecundity of 0.173 oocytes per mg of female total weight, and fractional spawning. The sex ratio did not differ from 1:1 during all sampled months. Sexual dimorphism related to hypertrophy of the male's distal portion of caudal filament was observed and males grew to greater lengths than females. Male gonadosomatic index (GSI) was significantly related to water depth, oxygen saturation and temperature. Female GSI was significantly related to water depth and hepatosomatic index.

scholarly journals Population structure and reproductive biology of the stone crab Xantho poressa (Crustacea: Decapoda: Xanthidae) in the ‘Corrales de Rota’ (south-western Spain), a human-modified intertidal fishing area

2009 ◽  
Vol 90 (2) ◽  
pp. 323-334 ◽  
Author(s):  
Eduardo D. Spivak ◽  
Elisabeth Arévalo ◽  
José A. Cuesta ◽  
J. Ignacio González-Gordillo
Keyword(s):  
Population Structure ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Gonadosomatic Index ◽  
Reproductive Season ◽  
Hepatosomatic Index ◽  
Stone Crab ◽  
Intertidal Crab ◽  
Western Spain ◽  
Complex Habitat

The present study describes the reproductive biology, population structure and life history traits of the abundant intertidal crab Xantho poressa. Between March 2007 and April 2008, a total of 1918 individuals were collected in Corrales de Rota (south-western Spain), a human-modified intertidal habitat characterized by an artificial high complexity. Suitable refuges for crabs (cobbles and boulders) are very abundant in this area and density (maximum of 50 ind*m−2) was directly related with the area covered by these stones. In spring and summer, size–frequency distributions showed a polymodal pattern with seasonal variations related to the incorporation of juveniles to the adult population. Newly settled juveniles were not found in the Corrales suggesting an ontogenetic migration from a distant recruitment habitat. The annual reproductive cycle was seasonal and successive peaks in the abundance of ovigerous females were observed in late spring and summer. Females probably produced multiple broods during a long intermoult period. The gonadosomatic index had a cyclic pattern of variation with peaks two weeks prior to those of ovigerous females; it was lower during the non-reproductive season. The hepatosomatic index was high during spring, decreased during summer and increased gradually at the end of the reproductive season. There was a monthly cycle of larval release resulting from a combination of a cyclic and synchronic ovarian maturity, oviposition and incubation; hatching took place during neap tides when the moon was at last quarter. The adaptive significance of the rhythmic reproduction and hatching observed may not be explained by the predator avoidance hypotheses. The overall sex-ratio did not differ from 1:1 but one male and several females coexist under a stone, indicating a female biased operative sex-ratio. The combination of a complex habitat, its use, and a strong sexual dimorphism suggest a refuge–defence polygenic mating system. The survival and fitness of X. poressa in the Corrales de Rota are probably enhanced by the availability of shelter, a consequence of a highly complex habitat, and probably, of human activity.

scholarly journals Seasonal variations in the population biology of Salmostoma bacaila (Cyprinidae) from a tributary of the Payra River, Bangladesh

2019 ◽  
pp. 113-119
Author(s):  
Ahamed Ahamed ◽  
Faruque Ahmed Zoarder ◽  
Jun Ohtomi
Keyword(s):  
Sex Ratio ◽  
Seasonal Variations ◽  
Population Biology ◽  
Sexual Maturity ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Spawning Season ◽  
Frequency Distributions ◽  
Size At Sexual Maturity ◽  
Management And Conservation

Some biological parameters of Salmostoma bacaila – including sex ratio, length-frequency distributions (LFDs), size at sexual maturity, spawning season, length-weight relationships (LWRs) and condition factor – were studied. Samples were collected seasonally during June 2017 to May 2018 from a tributary of the Payra River. The overall sex ratio was significantly different from the expected value of 1:1 (p < 0.001), in favour of male specimens. Females were significantly larger than males. Size at sexual maturity was estimated at 7.6~7.7 cm total length. Seasonal variations in the gonadosomatic index (GSI) indicate that the main spawning season is from spring to summer. The LWRs showed negative allometric growth in both sexes, but with clear seasonal variation. Fulton’s condition factor varied in both sexes and was attributed to variations in GSI with maturity. The fin¬dings of this study will be helpful for management and conservation of S. bacaila populations.

First report on the diet and reproductive biology of red-toothed triggerfish Odonus niger (Ruppell, 1836) from the south-eastern Arabian Sea

2021 ◽  
pp. 1-11
Author(s):  
Nitin Kanji Suyani ◽  
Mridula Rajesh ◽  
Kothanahally Mallegowda Rajesh
Keyword(s):  
Reproductive Biology ◽  
Arabian Sea ◽  
Feeding Habits ◽  
Gonadosomatic Index ◽  
Biological Information ◽  
The South ◽  
Spawning Period ◽  
South Eastern ◽  
Eastern Arabian Sea ◽  
Males And Females

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.

scholarly journals Length-weight relation, condition factor and gonadosomatic index of the whitemouth croaker, Micropogonias furnieri (Desmarest, 1823) (Actinopterygii: Sciaenidae), caught in Lençóis Bay, state of Maranhão, eastern Amazon, Brazil

2017 ◽  
Vol 65 (1) ◽  
pp. 1-8 ◽  
Author(s):  
James Werllen de Jesus Azevedo ◽  
Antonio Carlos Leal de Castro ◽  
Marcelo Henrique Lopes Silva
Keyword(s):  
Sex Ratio ◽  
Rainy Season ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Length Distribution ◽  
The State ◽  
Allometric Growth ◽  
First Semester ◽  
Length Relationship ◽  
Micropogonias Furnieri

Abstract The whitemouth croaker, Micropogonias furnieri, which is exploited off the state of Maranhão, Brazil, reinforces the need for maintenance programs of natural stocks of this species to assist in the management of this exploited resource. The aim of the present study was to describe aspects regarding its reproductive characteristics (gonadosomatic index and condition factor) and also the length distribution and weight-length relationships. The fish were caught in Lençóis Bay in the state of Maranhão (eastern Amazon) between June 2010 and July 2011. A total of 570 individuals were caught (318 males and 252 females). Differences in length were found between the sexes, with females larger than males. The sex ratio indicated a tendency for females to be more abundant in the rainy season (first semester), whereas males predominated in the dry season (second semester). The weight-length relationship indicated negative allometric growth for both sexes. The analysis of the variation in the condition factor suggests that lower values coincided with higher gonadosomatic index values and that this factor is a good reproductive indicator for M. furnieri in the region.

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