scholarly journals Reproductive Strategy of Chrysichthys nigrodigitatus (Lacepede, 1803) in a Natural Environment in the Nkam River, Littoral Cameroon

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Claudine Tekounegning Tiogué ◽  
Boddis Tsiguia Zebaze ◽  
Paul Zango ◽  
Minette Eyango Tomedi-Tabi
Keyword(s):  
Reproductive Strategy ◽  
Sexual Maturity ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Hepatosomatic Index ◽  
Long Period ◽  
Littoral Region ◽  
K Factor ◽  
The Mean ◽  
Future Work

A study on the reproductive strategy of Chrysichthys nigrodigitatus was conducted from October 2015 to August 2016, in the Nkam River in Yabassi, Littoral Region of Cameroon. For this purpose, 154 specimens of C. nigrodigitatus with total mean weight of 829.96 ± 829.58 g and total mean length of 367 ± 156 mm collected from artisanal fishermen were used. Twenty-nine (29) females at stage V of sexual maturity were selected for the evaluation of the fecundity. It appears that the oogenesis in C. nigrodigitatus is of an asynchronous type with multiple laying spread over a long period. The gonadosomatic index (GSI) peaks in June (17.9 ± 7.1 for females and 1.06 ± 0.27 for males). Hepatosomatic index (HSI) was higher in females than in males throughout the year. The mean condition factor K was 1.07 ± 0.09%. The breeding season occurred from April to October during the rainy season. Gonadosomatic and hepatosomatic indices were positively correlated with rainfall, contrary to the K factor, which has been strongly and negatively correlated with this physical parameter. The sex ratio of 1M: 1.5F was in favour of females, thus reflecting an “r” type reproductive strategy. Absolute fecundity was estimated at 1374 ± 1022 oocytes for individuals of 107.3 ± 111.9 g mean weight. Mean relative fecundity was 14 ± 3 oocytes/g of body weight. It was recommended that future work focuses on the captivity of this species.

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.

scholarly journals Reproductive Phenology and Size Structure Characteristics of Hypseleotris agilis (Herre, 1927) in Lake Mainit, Philippines

2020 ◽  
Vol 80 ◽  
pp. 35-42
Author(s):  
Joycelyn C. Jumawan ◽  
Paula Marie Hidalgo ◽  
Romell A. Seronay
Keyword(s):  
Native Species ◽  
Condition Factor ◽  
Size Structure ◽  
Gonadosomatic Index ◽  
Reproductive Phenology ◽  
Hepatosomatic Index ◽  
Fishery Resource ◽  
Gravid Females ◽  
Management And Conservation

Hypseleotris agilis locally known as Bugwan is a native species and one of the most abundant fishes of commercial value in Lake Mainit, Philippines. A total of 1,584 H. agilis from Lake Mainit near the mouth of Kalinawan and Puyo River were caught from May 2018 to February 2019 to determine the length-weight relationship (LWR), condition factor (K), gonadosomatic index (GSI) and hepatosomatic index (HSI) of this species. Positive allometric growth was observed for both sexes (b>3). Sex ratio indicated the dominance of males over females as much as 58.7%. The number of ripe males and gravid females was observed throughout the months of the collection, which indicates the ability of the fish species to spawn continuously throughout the year. Determination of GSI in both sexes showed higher values during November (males) and December (females). However, HSI values were relatively low during the spawning season, which would indicate the usage of energy for gonadal maturation. The K factor showed high values during the peak spawning months, directly proportional to GSI values. This study provides updated information for management and conservation of this important fishery resource in Lake Mainit.

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 Oocyte development in captive Atlantic horse mackerel Trachurus trachurus

2009 ◽  
Vol 66 (4) ◽  
pp. 623-630 ◽  
Author(s):  
Hilkka O. N. Ndjaula ◽  
Tom Hansen ◽  
Maria Krüger-Johnsen ◽  
Olav Sigurd Kjesbu
Keyword(s):  
Gonadosomatic Index ◽  
Oocyte Development ◽  
Horse Mackerel ◽  
Hepatosomatic Index ◽  
Oocyte Diameter ◽  
Trachurus Trachurus ◽  
The Mean ◽  
Threshold Variation ◽  
Index Condition ◽  
Atlantic Horse Mackerel

Abstract Ndjaula, H. O. N., Hansen, T., Krüger-Johnsen, M., and Kjesbu, O. S. 2009. Oocyte development in captive Atlantic horse mackerel Trachurus trachurus. – ICES Journal of Marine Science, 66: 623–630. This 13-month experimental study focused on developing oocyte production in 101 adult female Atlantic horse mackerel. In addition, proxies of energy patterns in relation to oocyte development were investigated. The fish were captured off western Norway and fed to satiation from October 2005 to November 2006 in two replicate adjacent circular tanks. Monthly histological examination of the ovaries indicated that vitellogenic oocytes were present at all times throughout the study period, but that oocyte development did not progress past the incipient migratory nucleus stage. The oocyte diameter (OD) threshold between pre-vitellogenic and vitellogenic oocytes and the mean OD of the leading cohort were investigated, and no hiatus was observed within the OD size distribution around the 185-µm pre-vitellogenic and vitellogenic threshold. Variation in gonadosomatic index, hepatosomatic index, condition factor, and fat content (as measured by the use of a Distell Fish Fatmeter) increased with oocyte development. The observed development of oocyte recruitment and the absence of a hiatus in the oocyte distribution are characteristics of an asynchronous spawner. The species seems to have a prolonged spawning season, judging from the advanced and variety of maturity stages throughout the study period.

scholarly journals Quality of Nephrops as food for Atlantic cod (Gadus morhua L.) with possible implications for fisheries management

2004 ◽  
Vol 61 (6) ◽  
pp. 983-991 ◽  
Author(s):  
Björn Björnsson ◽  
Maria Álvaro Dongala Dombaxe
Keyword(s):  
Growth Rate ◽  
Gadus Morhua ◽  
Specific Growth ◽  
Condition Factor ◽  
Atlantic Cod ◽  
Gonadosomatic Index ◽  
Conversion Ratio ◽  
Food Conversion ◽  
The Mean

Abstract Nephrops was found to be of low quality as food for cod. In a laboratory experiment the mean specific growth rate of 1 kg cod was 0.184 and 0.415% d−1 when fed to satiation on Nephrops and capelin, respectively. This large difference in growth rate resulted not only from less intake of Nephrops (1.19 kg cod−1) than capelin (1.55 kg cod−1) but also because more Nephrops (4.6 kg) than capelin (2.2 kg) were required to produce each kilogramme of cod. Higher food conversion ratio was consistent with lower fat content of Nephrops (1.3%) than capelin (9.2%) but the exoskeleton also reduced the digestion rate of Nephrops. In the groups where Nephrops and capelin of equal mean weight were offered simultaneously, 40% of the diet consisted of Nephrops during the first week and 10% during the final seven weeks of the experiment. At the end of the experiment, condition factor, liver index, and gonadosomatic index were significantly lower for cod fed on Nephrops (0.967, 5.7, 7.1, respectively) than for those fed on capelin (1.086, 15.8, 11.2, respectively). These results suggests that predation by cod on Nephrops might be reduced by regular release of capelin or other similar food in the distributional areas of Nephrops.

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 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 Ecological aspects of Lebiasina erythrinoides (Characiformes: Lebiasinidae) from an andean piedmont stream in Colombia

2016 ◽  
Vol 21 (1) ◽  
pp. 83 ◽  
Author(s):  
Javier Alejandro Maldonado Ocampo ◽  
Alexander Urbano Bonilla ◽  
Jhon Zamudio
Keyword(s):  
Standard Length ◽  
Sexual Maturity ◽  
Condition Factor ◽  
Hydrological Cycle ◽  
Immature Stage ◽  
Minimum Size ◽  
Ecological Aspects ◽  
The Mean ◽  
Reproductive Events ◽  
Reproduction Stage

The present study describes ecological aspects of <em>Lebiasina erythrinoides</em>; 200 individuals were sampled throughout an annual hydrological cycle from October 2008 to September 2009 in La Calaboza stream, a Piedmont tributary of the Rio Cravo Sur. The studied population had more females than males (1.5:1) and preferred habitats dominated by shoreline vegetation and rocky substrates. Prior to reproductive events, individuals presented an increase in the condition factor (K) and the gonosomatic index (GSI). On average, 648.8 oocytes are discharged twice a year: at the beginning of the rainy season, and during falling water phase. The mean sizes at sexual maturity found for females were 73.5 mm standard length (SL) and for males 70 mm SL. Rounding up, an average minimum size of capture of 75 mm SL is proposed. Most specimens of the population (65 %) were found to be maturing or mature (stages II and III), 28.5 % immature (stage I), 5.0 % in post reproduction stage V, and 1.5 % in reproductive phase (IV). Results suggest this species is omnivorous with a preference for invertebrates (IRI = 41.2 %) and vegetal material (IRI = 27.8 %), but also includes a variety of other items. The values of the diet are correlated with hydrological cycle and size.

scholarly journals 17α-Methyltestosterone can induce masculinisation and sterilisation in amur carp Cyprinus rubrofuscus Lacepede 1803

2019 ◽  
Vol 66 (3) ◽  
Author(s):  
K.S. Suma ◽  
N. Basavaraja ◽  
N. Manjappa
Keyword(s):  
Normal Development ◽  
Condition Factor ◽  
Gonadosomatic Index ◽  
Gonadal Development ◽  
Control Fish ◽  
Hepatosomatic Index ◽  
Slight Variation ◽  
Loss Of Weight ◽  
Treated Fish ◽  
Control Loss

To find a suitable solution to the problem of early sexual maturation and unwanted reproduction during grow-out, the present study was aimed at production of sterile or monosex population of Amur carp through endocrine manipulation. In this investigation, 24-day-old Amur carp fry were fed with diets containing 17α-methyltestosterone (17α-MT) at dosages of 200-1000 ppm for 30 d. While 17α-MT incorporation at 400 ppmresulted in complete masculinization, 600 ppm induced 100% sterilization. 17α-MT at 200 ppm induced the production of intersex and sterile fish. At 800 ppm, it produced 8.33% male, 8.33% female and 83.34% sterile fish, whereas 1000 ppm yielded 63.63% male, f9.10% female and 27.27% sterile fish. After 168 d post-treatment rearing, increase in fish weight was 16.01- 233.15%, over control. Loss of weight due to evisceration was 8.75-12.43% in control, while it was 7.31-9.78% in sterile fish, indicating the availability of more edible meat in the latter. MT-treated carp showed a slight variation in survival, gonadosomatic index (GSI), hepatosomatic index (HSI), viscerosomatic index (VSI) and condition factor. The histology of gonads revealed normal development of ovary and testis in control fish, but in 17α-MT treated fish the gonadal development was either normal or abnormal in male and slightly suppressed in female. Intersex fish had both ovarian and testicular tissues, while sterile fish possessed mostly connective tissue.

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