A study on seasonal abundance,morphometric and meristic data,growth pattern,condition fector,sex ratio and gonadosomatic index of Liza falcip-innis(Wlenciennes,1836)from the Ojo axis of Badagry creek,Nigeria was condu...A study on seasonal abundance,morphometric and meristic data,growth pattern,condition fector,sex ratio and gonadosomatic index of Liza falcip-innis(Wlenciennes,1836)from the Ojo axis of Badagry creek,Nigeria was conducted from May 2019 to March 2020.A total of 1012 species were randomly selected,having 499 females and 513 males.The length frequency analysis and length-weight relationships(LWR)were determined.Sex ratio was determined by Chi-square analysis.The results showed that morphometric data are:0.5-2.5 mm for ED,2.1-12 mm for HL,1.7-8.1 mm for HD,2.5-11.7 for BD,2.6-233.3 mm for TL and 9.23-1006 g for BW for the combined sexes.The slope(b)shows an allometric growth pattern.The intercept'a'and slope'b'of the LWR(LogW=a+bLogL)were Log W=15.39+0.34 LogL(r=0.54)for combined sexes,Log W=12.49+0.02 log L(r=0.38)for males and Log W=18.23+0.01 log L(r=0.16)for females.The length frequency distribution indicated that species were dominated by two year classes(Ages 1 and 2).Condition factors were generally low.The values ranged between 0.68-0.85 for combined sexes.The gonadosomatic index for female was highest in August,2019(17.77%)with Mean±SD of 2.88±0.75;which indicated the peak of spawning period in the study area.Sex ratio difference was significant(P<0.05).Sexual differences were significant;the females are phenotypically larger than the male.展开更多
Reproductive biology of Leiognathus splendens was studied by using the samples collected from the catches of trawl fisheries in Myeik coastal waters during January to December 2014.Spawning takes place throughout the ...Reproductive biology of Leiognathus splendens was studied by using the samples collected from the catches of trawl fisheries in Myeik coastal waters during January to December 2014.Spawning takes place throughout the year,with a peak during April-May and September-December.The observed length at first maturity was 9.0 cm total length in males and 8.4 cm in females.The mean gonadosomatic index was more prominently in females(2.5)than males(1.5).Sex ratio(1 male:1.1 females)also indicates the general dominant of females over males Fecundity varied from 6120 to 58412 eggs.Relationship of fecundity to fish length,fish weight and ovary weight showed that fecundity is more related to the gonad weight(r=0.9)than length(r=0.8)and weight of fish(r=0.7).展开更多
The study aims to afford a deeper knowledge on reproductive biology of Mystus bleekeri from Surma River,Bangladesh in a multidisciplinary way.Though,the species is in demand as food and ornamental fish in Bangladesh b...The study aims to afford a deeper knowledge on reproductive biology of Mystus bleekeri from Surma River,Bangladesh in a multidisciplinary way.Though,the species is in demand as food and ornamental fish in Bangladesh but still now comprehensive details on reproductive biology of this species is scanty.Total 600 fish samples were derived from commercial catches from July 2018 to June 2019.Periodic differences in sex ratio,size distribution,condition factor(Kn),fecundity,gonadosomatic index and gonadal maturation cycle were assessed.The results showed 384(64%)female and 216(36%)male with an overall sex ratio of 1.77:1(female:male).Mean total length(TL)and body weight(BW)of all fish studied were 14.85±3.38 cm TL and 27.54±15.76 g,respectively.The Kn varied with length groups,the highest(1.45±0.23)and lowest(0.89±0.18)values obtained in 16.0-16.9 and 10.0-10.9 cm TL groups,respectively.The highest Kn was documented in October while the lowest was in January.Monthly GSI values showed two peaks in July and November for both the sexes.The fecundity was found to vary from 1120 to 14790 eggs with average value of 4968±3047 with 14.4-18.3 cm in TL and 19.97-34.7g in BW.The relationship of fecundity with TL and BW was F=1.385TL13.405,r^(2)=0.885 and F=5.201BW^(4.827),r^(2)=0.944.Partial behavior of spawning together with allochronic oocytes development has also been found through histology.The results of this study could be used for predicting the response of populations of fish in Surma River and/or other where to human interferences and environmental change.展开更多
Objective:To determine the spawning activity using gonadosomatic index(GSI)and gonad histology the Balistes capriscus(Teleostei:Balistidae)of the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea).Methods:...Objective:To determine the spawning activity using gonadosomatic index(GSI)and gonad histology the Balistes capriscus(Teleostei:Balistidae)of the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea).Methods:The reproductive biology of the species,based on 756(480 females and 276 males),collected from commercial catches at several fishing ports including Chebba,Kerkennah and Zarzis at respective GPS coordinates(34°14'N,11°06'E),(34°45'N,11°17'E),(33°41'N,11°48'E)was studied over 28 months(January 2008-April 2010)using GSI and gonad histology.Sizes used in this study ranged from 11.30 to 45.60 cm in fork length.Results:Both GSI and gonad histology suggest that spawning activity occurred mainly between July and mid-September with a peak in July,coinciding with summer time.The first maturation occurred at 20.26 cm fork length for females and 21.30 cm fork length for males.The monthly values of hepatosomatic index and condition factor(K)indicated that the liver is the main organ responsible for the mobilization process of the energizing reserves during the sexual cycle.Conclusions:It is the first inventory of gonadal maturation and histological observations of the grey triggerfish Balistes capriscus Gmelin,1789(Teleostei:Balistidae)in the Gulf of Gabès,(Southern Tunisia,Central Mediterranean Sea).展开更多
Objective:To investigate the effect of Tetracarpidium conophorum(T.conophorum)seed powder as dietary supplementation on the reproductive indices in male Clarias gariepinus(C.gariepinus)broodstocks.Methods:Fifteen outd...Objective:To investigate the effect of Tetracarpidium conophorum(T.conophorum)seed powder as dietary supplementation on the reproductive indices in male Clarias gariepinus(C.gariepinus)broodstocks.Methods:Fifteen outdoor concrete tanks consisting of triplicates for each treatment group were used.Triplicate groups of male C.gariepinus[(303.22±1.89)g body weight]were fed with four diets supplemented T.conophorum seed powder respectively,a control diet without T.conophorum seed powder 2 times a day at 3%of body weight for 70 days.Male C.gariepinus broodstocks[average individual weight,(303.22±1.89)g]were randomly distributed with density of 10 fish into 15 outdoor concrete tanks.At the end of the 70-day experiment,gonado-somatic index and reproductive indices were determined.Results:Fish fed experimental diets showed significantly improved gonado-somatic index and reproductive indices over the control treatment.Higher gonado-somatic index and reproductive indices were recorded for the fish fed diet of 200 mg/kg T.conophorum seed powder compared to other experimental diets.The results indicated that supplement diets with medicinal plant(T.conophorum)enhanced growth and improved gonado-somatic index,and reproductive indices of male C.gariepinus broodstocks.Conclusions:T.conophorum have a potential pro-fertility property which can be exploited in fish seed production by hatchery operators.展开更多
文摘A study on seasonal abundance,morphometric and meristic data,growth pattern,condition fector,sex ratio and gonadosomatic index of Liza falcip-innis(Wlenciennes,1836)from the Ojo axis of Badagry creek,Nigeria was conducted from May 2019 to March 2020.A total of 1012 species were randomly selected,having 499 females and 513 males.The length frequency analysis and length-weight relationships(LWR)were determined.Sex ratio was determined by Chi-square analysis.The results showed that morphometric data are:0.5-2.5 mm for ED,2.1-12 mm for HL,1.7-8.1 mm for HD,2.5-11.7 for BD,2.6-233.3 mm for TL and 9.23-1006 g for BW for the combined sexes.The slope(b)shows an allometric growth pattern.The intercept'a'and slope'b'of the LWR(LogW=a+bLogL)were Log W=15.39+0.34 LogL(r=0.54)for combined sexes,Log W=12.49+0.02 log L(r=0.38)for males and Log W=18.23+0.01 log L(r=0.16)for females.The length frequency distribution indicated that species were dominated by two year classes(Ages 1 and 2).Condition factors were generally low.The values ranged between 0.68-0.85 for combined sexes.The gonadosomatic index for female was highest in August,2019(17.77%)with Mean±SD of 2.88±0.75;which indicated the peak of spawning period in the study area.Sex ratio difference was significant(P<0.05).Sexual differences were significant;the females are phenotypically larger than the male.
文摘Reproductive biology of Leiognathus splendens was studied by using the samples collected from the catches of trawl fisheries in Myeik coastal waters during January to December 2014.Spawning takes place throughout the year,with a peak during April-May and September-December.The observed length at first maturity was 9.0 cm total length in males and 8.4 cm in females.The mean gonadosomatic index was more prominently in females(2.5)than males(1.5).Sex ratio(1 male:1.1 females)also indicates the general dominant of females over males Fecundity varied from 6120 to 58412 eggs.Relationship of fecundity to fish length,fish weight and ovary weight showed that fecundity is more related to the gonad weight(r=0.9)than length(r=0.8)and weight of fish(r=0.7).
基金supported by Sylhet Agricultural University Research System(SAURES)Bangladesh through the research grant#SAU/Director(Research)-80/18/351(15).
文摘The study aims to afford a deeper knowledge on reproductive biology of Mystus bleekeri from Surma River,Bangladesh in a multidisciplinary way.Though,the species is in demand as food and ornamental fish in Bangladesh but still now comprehensive details on reproductive biology of this species is scanty.Total 600 fish samples were derived from commercial catches from July 2018 to June 2019.Periodic differences in sex ratio,size distribution,condition factor(Kn),fecundity,gonadosomatic index and gonadal maturation cycle were assessed.The results showed 384(64%)female and 216(36%)male with an overall sex ratio of 1.77:1(female:male).Mean total length(TL)and body weight(BW)of all fish studied were 14.85±3.38 cm TL and 27.54±15.76 g,respectively.The Kn varied with length groups,the highest(1.45±0.23)and lowest(0.89±0.18)values obtained in 16.0-16.9 and 10.0-10.9 cm TL groups,respectively.The highest Kn was documented in October while the lowest was in January.Monthly GSI values showed two peaks in July and November for both the sexes.The fecundity was found to vary from 1120 to 14790 eggs with average value of 4968±3047 with 14.4-18.3 cm in TL and 19.97-34.7g in BW.The relationship of fecundity with TL and BW was F=1.385TL13.405,r^(2)=0.885 and F=5.201BW^(4.827),r^(2)=0.944.Partial behavior of spawning together with allochronic oocytes development has also been found through histology.The results of this study could be used for predicting the response of populations of fish in Surma River and/or other where to human interferences and environmental change.
基金Supported by the Faculty of Sciences,Sfax,Tunisia
文摘Objective:To determine the spawning activity using gonadosomatic index(GSI)and gonad histology the Balistes capriscus(Teleostei:Balistidae)of the Gulf of Gabès(Southern Tunisia,Central Mediterranean Sea).Methods:The reproductive biology of the species,based on 756(480 females and 276 males),collected from commercial catches at several fishing ports including Chebba,Kerkennah and Zarzis at respective GPS coordinates(34°14'N,11°06'E),(34°45'N,11°17'E),(33°41'N,11°48'E)was studied over 28 months(January 2008-April 2010)using GSI and gonad histology.Sizes used in this study ranged from 11.30 to 45.60 cm in fork length.Results:Both GSI and gonad histology suggest that spawning activity occurred mainly between July and mid-September with a peak in July,coinciding with summer time.The first maturation occurred at 20.26 cm fork length for females and 21.30 cm fork length for males.The monthly values of hepatosomatic index and condition factor(K)indicated that the liver is the main organ responsible for the mobilization process of the energizing reserves during the sexual cycle.Conclusions:It is the first inventory of gonadal maturation and histological observations of the grey triggerfish Balistes capriscus Gmelin,1789(Teleostei:Balistidae)in the Gulf of Gabès,(Southern Tunisia,Central Mediterranean Sea).
文摘Objective:To investigate the effect of Tetracarpidium conophorum(T.conophorum)seed powder as dietary supplementation on the reproductive indices in male Clarias gariepinus(C.gariepinus)broodstocks.Methods:Fifteen outdoor concrete tanks consisting of triplicates for each treatment group were used.Triplicate groups of male C.gariepinus[(303.22±1.89)g body weight]were fed with four diets supplemented T.conophorum seed powder respectively,a control diet without T.conophorum seed powder 2 times a day at 3%of body weight for 70 days.Male C.gariepinus broodstocks[average individual weight,(303.22±1.89)g]were randomly distributed with density of 10 fish into 15 outdoor concrete tanks.At the end of the 70-day experiment,gonado-somatic index and reproductive indices were determined.Results:Fish fed experimental diets showed significantly improved gonado-somatic index and reproductive indices over the control treatment.Higher gonado-somatic index and reproductive indices were recorded for the fish fed diet of 200 mg/kg T.conophorum seed powder compared to other experimental diets.The results indicated that supplement diets with medicinal plant(T.conophorum)enhanced growth and improved gonado-somatic index,and reproductive indices of male C.gariepinus broodstocks.Conclusions:T.conophorum have a potential pro-fertility property which can be exploited in fish seed production by hatchery operators.
