Aspects of the reproductive biology of Pseudotolithus typus (Bleeker, 1863) from qua Iboe River Estuary, Nigeria

2020 ◽  
Vol 35 (1) ◽  
pp. 57-66
Author(s):  
A.I. Nta ◽  
A.W. Akpan ◽  
A.O. Okon ◽  
I.K. Esenowo

The study was conducted to assess the reproductive biology and condition index of Pseudotolithus typus in Qua Iboe Estuary using standard methods. A total of 580 fish specimen were sampled over a period of 8 months (January – August, 2018). Condition index was generally low with the highest value of 1.03 recorded in the month of April. The overall mean condition index significantly deviated (p<0.05) from the expected value of 1.0. Male-female ratio of the species showed female dominance. Significant variation (p<0.05) were observed in condition and gonadosomatic indices with peak values in the months of March and July for females. Male fish showed no seasonality in gonadosomatic index. The average fecundity ranged from 2140 eggs to 8560 eggs with mean value of 4891±641 eggs. Positive correlation was observed between fecundity and total length, body weight, standard length and gonad weight of the fish. Thus, it could be concluded that P. typus is a dual seasonal spawner having spawning periods early in the year (March) and in the peak of wet season (July). Keywords: Pseudotolithus typus, condition index, gonadosomatic index, fecundity, estuary.

Author(s):  
Matheus Oliveira Freitas ◽  
Gecely Rodrigues Alves Rocha ◽  
Paulo De Tarso Da Cunha Chaves ◽  
Rodrigo Leão De Moura

The reproductive biology of the lane snapper, Lutjanus synagris, was evaluated from 770 specimens (434 females and 336 males) obtained on the Abrolhos Bank, eastern Brazil, between May 2005 and October 2007. Total length ranged from 14.7 to 56.0 cm for females and from 16.5 to 54.3 cm for males, with size composition not varying significantly between sexes. Five distinct maturity stages were identified based on macroscopic and histological examination of the gonads. Mean value of the gonadosomatic index (GSI) for females peaked in September and October, with a secondary peak in February and March. Histological analyses confirmed the reproductive cycle inferred by GSI variation. Asynchronous-type ovarian development was observed, and batch fecundity ranged from less than 104,743 oocytes for a 25.5 cm female of to 568,400 oocytes for a 56.0 cm female (250.0 and 2260 g, respectively), with an average of 345,700 oocytes. The reproductive parameters obtained for L. synagris in the Abrolhos Bank were similar to those reported in studies in northern Brazil and the north-west Atlantic. The species is an important fishery resource in the study region, and management measures are needed before the species becomes overfished. Exploitation occurs largely during spawning aggregations, a situation that has caused other lane snapper populations (and congeners) to decline acutely elsewhere. Our results provide support for size limits and seasonal spawning closures on the Abrolhos Bank, a region that sustains artisanal fisheries involving >20,000 fishermen.


2014 ◽  
Vol 04 (02) ◽  
pp. 017-020
Author(s):  
Dharma Rao V. ◽  
Rajaneesh Reddy M. ◽  
Srikanth K. ◽  
Raj Kumar Prakash B. ◽  
Satya Prasad A. ◽  
...  

Abstract: Objective: To determine the prevalence of chronic atrial fibrillation (AF) in a tertiary care center and to identify the clinical profile of chronic AF in hospitalized patients. Methods: All patients admitted to Mamata General Hospital in medicine/cardiology wards with chronic AF (persistent and permanent) during the period January 2012 to December 2012 were included into the study. The principal exclusion criteria were new onset AF and acute AF. Results: During the study period, 49 patients were admitted with chronic AF with an average of 45.44 years. A slight female dominance was seen with male: female ratio of 1:1.2. Half of the patients (51%) were below the age 50 years. The elderly age group comprised of only 16.3% of cases. The commonest presenting complaint was dyspnea followed by palpitation. Rheumatic valvular heart disease was seen more commonly in people below the age of 50 years whereas hypertension and ischemic heart disease after 50 years. Heart failure was the commonest condition associated with the chronic AF and was the cause of hospitalization in almost fifty percent of cases Conclusion: Chronic AF is still a cause of concern in India in people below the age of 50 years due to high prevalence of rheumatic fever inspite of advances in the medical field.


2007 ◽  
Vol 5 (4) ◽  
pp. 479-484 ◽  
Author(s):  
Andréa L. Neuberger ◽  
Elineide E. Marques ◽  
Carlos S. Agostinho ◽  
Rafael J. de Oliveira

In order to evaluate aspects of the reproductive biology of Rhaphiodon vulpinus in the Upper and Middle Tocantins River, samples were taken monthly from October, 1999 through September, 2001, by means of gill nets. Males, which were more abundant than females (chi2 146.87: df=1: p<0.05), matured at a smaller size. The reproductive period of the species extended essentially from November through January, with a peak of activity in November. Fecundity, with an estimated mean value of 98,185 oocytes, varied from 38,177 to 215,841 oocytes, and it did not correlate with the length of the individual female analyzed (r=0.4663: p=0.206). Relative fecundity was 130.6 oocytes/g total weight. Mature oocytes had a mean diameter of 0.98 mm, corresponding to a volume of 0.50 mm³.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Hidetoshi Urakawa ◽  
Jaffar Ali ◽  
Rheannon D. J. Ketover ◽  
Spencer D. Talmage ◽  
Juan C. Garcia ◽  
...  

Understanding the biodegradation potential of river bacterioplankton communities is crucial for watershed management. We investigated the shifts in bacterioplankton metabolic profiles along the salinity gradient of the Caloosahatchee River Estuary, Florida. The carbon source utilization patterns of river bacterioplankton communities were determined by using Biolog EcoPlates. The number of utilized substrates was generally high in the upstream freshwater dominated zone and low in the downstream zone, suggesting a shift in metabolic profiles among bacterioplankton assemblages along the estuarine gradient. The prokaryotic cell numbers also decreased along the estuarine salinity gradient. Seasonal and site-specific differences were found in the numbers of utilized substrates, which were similar in summer and fall (wet season) and winter and spring (dry season). Bacterioplankton assemblages in summer and fall showed more versatile substrate utilization patterns than those of winter and spring communities. Therefore, our data suggest that microbial metabolic patterns in the subtropical estuary are likely influenced by the water discharge patterns created by dry and wet seasons along the salinity gradient.


2021 ◽  
Vol 21 (4) ◽  
pp. 149-159
Author(s):  
Dulon Roy ◽  
Ashish Kumer Sarker ◽  
Abu Musa Mohammad Khairul Abedin ◽  
Smita Sarker ◽  
Kazi Nahida Begum ◽  
...  

An experiment was conducted to observe some biological aspects including growth, sex ratio, gonadal maturity, artificial insemination, fecundity, fertilization, hatching and larval development of O. pabda in a private hatchery. Total weight of the sampled fish varied from 1.60±0.43 to 111.12±6.83 g and length varied from 3.57±0.65 to 21.22±1.84 cm with the SGR 2.85±0.18 and ADG 0.73±0.05. The length and weight of the fish had a strong correlation (r²=0.966). Female dominance over male has been observed in the species. The male to female ratio was 1:1.48. Females were 16.8 cm in length at first maturity, while males were 16.6 cm in length. The GSI of female were ranged from 2.93 to 4.77 with the mean of 3.77±0.60 during the study period. The fecundity of O. pabda was ranged from 5675 to 19626 with the mean of 12503±4192 for the corresponding length 21.23±1.71, body weight 111.12±7.6 and gonad weight 4.19±0.87. Fertilization rate, hatching rate and larval development observed during the experiment. Scattered diagram for length-weight, fecundity-length, fecunditybody weight and fecundity-gonad weight relationship shows a perfect correlation both arithmetically and logarithmically.


2021 ◽  
Vol 25 (5) ◽  
pp. 841-845
Author(s):  
C.A.E. Ibhadode ◽  
I.R. Ilaboya

Groundwater pollution by heavy metals such as lead, copper, nickel and iron is one of the major environmental issues of concern which has developed into a widely studied area. In this study, attempt was made to investigate the level of heavy metals in selected boreholes around the vicinity of cemeteries in Benin City. Seventy-two (72) samples of groundwater were taken from boreholes in 9 stations around the three cemeteries in Benin City on monthly basis. The samples were analysed for 7 heavy metals, in accordance with standard procedures. The heavy metals include; Zinc, Lead Iron, Copper, Cadmium, Nickel and Mercury. From the results of the study, a variation in the mean concentration of zinc was observed. The mean concentration of zinc in site 1 was 0.450mg/l, for site 2, it was 0.140mg/l and for site 3, it was 1.0533mg/l. For iron, mean concentration was 0.072mg/l in site 1. For site 2, mean concentration of iron was 2.140mg/l and for site 3, mean concentration of iron was 0.560mg/l. It was further revealed based on the results that mean value of heavy metals in groundwater around cemeteries in Benin City were generally lower during dry season compared to wet season. In addition, result of computed pollution index (Pi) revealed that the heavy metal with the highest potential to pollute groundwater is Cadmium, with Pi of 0.5333 and 0.400 representing dry season and wet season respectively.


1994 ◽  
Vol 45 (3) ◽  
pp. 413 ◽  
Author(s):  
DT Brewer ◽  
SJM Blaber ◽  
DA Milton ◽  
JP Salini

Caranx bucculentus is the most abundant secondary consumer and the most important predator of commercially important penaeids in the Gulf of Carpentaria. More than 18 000 individuals of this species were collected from 406 trawls during 13 cruises in the Gulf of Carpentaria from 1986 to 1991. The species was most abundant in coastal waters, with a maximum biomass at a depth of 28.1 m. Catches were higher in prawn-trawling grounds than elsewhere in the gulf, and prawns comprised a greater proportion of the diet than is the case for other predatory fishes. Interannual variations in biomass occurred, but there were no differences between cruises or seasons. The decreased catches at night may have resulted from vertical die1 migration of C. bucculentus. Sexual maturity is reached at 110 mm standard length and about one year of age, which is much younger than in congeners. Back-calculated birth dates of C. bucculentus show year-round recruitment that peaks in the pre-wet season months of spring, and gonadosomatic index values are generally higher in the pre-wet season than in the wet season. Gonadosomatic index values remain relatively high (> 1.0), which indicates continuous spawning by C. bucculentus in the gulf. Other large tropical species of Caranx spawn annually, in summer. C. bucculentus fecundities range from 18 000 eggs for a 120-mm fish to about 650 000 eggs for a 460-mm fish. A possible switch is seen in the sex ratio-males seem to predominate at smaller sizes, whereas females seem to predominate among bigger fish. MULTIFAN length-frequency analysis gave values of L∞ = 538.8 mm (8 years old) and K= 0.305 year -1. A growth rate of 822 mm year-1 at L∞/2 is comparable to the growth rates of other tropical carangids. The diet of C. bucculentus throughout the gulf is dominated by epibenthic crustaceans and teleosts.


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.


2021 ◽  
Vol 36 (1) ◽  
pp. 75-82
Author(s):  
J. Otoyo ◽  
S.M. Ameh ◽  
O.K. Achema

Studies on identification of species, fecundity and development stages of blue crab, (Callinectes amnicola) were investigated at the Cross River Estuary between the months of December, 2018 and May, 2019. The parameters used for the study were gonadosomatic and hepatosomatic indices, egg diameter and counts. All measurements followed standard procedures. Gonadosomatic index was at its peak in December (88.9) and April (83.3). This coincided with the peak in egg size suggesting that spawning occurred twice within the period.The low values of hepatosomatic index around December (1.20) and April (0.45) added to confirm the spawning in these months. The species spawns at a mean egg size of 17.55mm. The dimension of crabs examined were in the following range: carapace length 40.0 to 70.0mm, carapace width, 5.0 to 60mm and body weight 40.0 to 140.0g. The relationship between fecundity and weight of crab was  significant (r = 0.295: p<0.05), indicating positive correlation. Absolute fecundity of the species ranged between 1,375 and 225,132 eggs. The smallest crab with egg had a carapace width of 39.5mm and weight of 46.9g. Spawning at this size seems to be a strategy adopted by the species to cope with exploitation pressure. The result of this study revealed that C. amnicola had a high reproductive potentials. Hence, adequate regulation is required to enhance sustainability of the species in the Cross River Estuary.


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