Reproductive parameters of blue shark, Prionace glauca, and other sharks in the Gulf of Guinea

1995 ◽  
Vol 46 (6) ◽  
pp. 967 ◽  
Author(s):  
JA Castro ◽  
J Mejuto
Keyword(s):  
Sex Ratio ◽  
Fork Length ◽  
Reproductive Parameters ◽  
Gulf Of Guinea ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Embryo Number ◽  
The Mean ◽  
Gravid Females ◽  
The Right

In total, 1967 pelagic sharks of eight different species were sampled in waters of the Gulf of Guinea between June and August 1993 by commercial longline gear. Catches of Prionace glauca and Sphyma zygaena included a large number of pregnant females, making it possible to calculate some of their reproductive parameters. In total, 419 gravid females of P. glauca were caught, ranging in size from 170 to 260 cm fork length. The size at which 50% of females have embryos was determined to be 180 cm FL. Examination of the uteri from 128 of these females showed a higher number of embryos (59-60%) in the right uterus. The mean number of embryos was 37. Data on embryo size suggests that P. glauca may have a west-east migration to give birth along the Atlantic equatorial line. The embryonic sex ratio was 1 : 1. In the same catch there were 21 gravid females of S. zygaena. No difference in the number of embryos between uteri was found in this species. Mean embryo number was 33.5 and embryonic sex ratio was 1 : 1.

Aspects of the reproductive biology of the blue shark Prionace glauca (Linnaeus, 1758) in the coastal waters of Ivory Coast, West Africa

2019 ◽  
Vol 99 (06) ◽  
pp. 1435-1441 ◽  
Author(s):  
Kouassi Yves Narcisse Kouamé ◽  
Kouadio Justin Konan ◽  
Nahoua Issa Ouattara ◽  
Tidiani Koné
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Coastal Waters ◽  
Ivory Coast ◽  
Abundant Species ◽  
Reproductive Parameters ◽  
Gulf Of Guinea ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Total Length

AbstractThe blue shark Prionace glauca is the most abundant species in the artisanal driftnet fishery off the coastal waters of Ivory Coast. The reproductive parameters were investigated with the aim of providing basic information on the reproductive biology for fisheries management. A total of 424 specimens (256 males and 168 females) ranging from 170–330 cm in total length (TL) were sampled between August 2014 and November 2016. Sample for embryonic sex ratio was obtained from 18 litters of 503 individuals (255 males and 248 females). The embryonic sex ratio was not significantly different from 1:1 (χ2 = 0.10, P > 0.05, N = 503). The size at 50% maturity (L50) was 218.1 cm TL for males and 223.3 cm TL for females. The litter size based on the number of embryos varied from 6 to 62, with an average of 30 embryos. Mating started in July whereas ovulation, fertilization and uterine eggs occurred in late October–November. Smallest embryos of 3–5 cm in stretch total length (STL) appeared in uterus from November to January. The embryo size varied widely among months, and well-pigmented embryos were already present in April–May samples, although most of them occurred in August–September, suggesting a gestation period of around 11 months. The absence of neonates in catches, as well as parturition females, does not support a hypothesis that parturition takes place in the Gulf of Guinea.

scholarly journals Reproductive Biology of Round Sardinella (Sardinella Aurita) (Valenciennes, 1847) in Senegalese Coastal Waters

2018 ◽  
Vol 9 (1) ◽  
pp. 31
Author(s):  
Ismaïla NDIAYE ◽  
Alassane SARR ◽  
Alioune FAYE ◽  
Modou THIAW ◽  
Malick DIOUF ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Coastal Waters ◽  
Sexual Maturity ◽  
Reproductive Parameters ◽  
Monthly Variation ◽  
Relative Fecundity ◽  
The Mean ◽  
Sardinella Aurita ◽  
Somatic Index

In this study, a total of 1068 specimens Sardinella aurita of which 553 females and 515 males were examined. The objectif of this study was to determine the reproductive parameters of Sardinella aurita. The sex ratio was significantly in favor of females (55%). The size at first sexual maturity was estimated at 18.9 cm for females and 18.0 cm for males. The monthly variation of sexual maturity stages and gonado-somatic index (GSI) allowed to locate the reproduction periods from February to June and from September to December. The mean absolute fecundity was estimated at 110.794 ± 7582 oocytes whereas relative fecundity was about 422 ± 26 oocytes per gram of female.

scholarly journals Some Aspects of Biology of Chola Punti Puntius Chola (Hamilton) from the Kangsa River

1970 ◽  
Vol 45 (4) ◽  
pp. 309-314
Author(s):  
Bi K Saha ◽  
A Saha
Keyword(s):  
Sex Ratio ◽  
Standard Length ◽  
Condition Factor ◽  
Fork Length ◽  
Head Length ◽  
Mean Values ◽  
Snout Length ◽  
Total Length ◽  
Relative Condition Factor ◽  
The Mean

The mean values of total length (75.89 ± 13.09 mm), standard length (54.98 ± 7.07 mm), fork length (60.86 ± 9.14 mm), head length (14.75 ± 2.05 mm), snout length (3.79 ± 0.61 mm), pre-dorsal length (31.53 ± 3.18 mm), height of body (20.2 ± 4.11 mm) and total weight (6.62 ± 3.55g) of combined sex of Puntius chola were calculated. Relationships between total length and standard length, fork length, head length, snout length and pre-dorsal length of Puntius chola were found to be linear, positive and highly significant. The length-weight relationship in male, female and combined sex were determined as Log W=-4.510+2.810 Log L, LogW=-4.204+2.685 Log L and Log W=4.465+2.808 Log L respectively. The mean values of condition factor from observed value (ko) of male, female and combined sex were determined as 1.36 ± 0.089, 1.599 ± 0.181 and 1.515 ± 0.192 respectively. The mean values of condition factor from calculated value (kc) of male, female and combined sex were found to be 1.362 ± 0.054, 1.6 ± 0.124 and 1.511 ± 0.075 respectively. The mean values of relative condition factor of male, female and combined sex were registered as 0.999 ± 0.044 , 0.999 ± 0.064 and 0.999 ± 0.112 respectively. Sex ratio was found to be 1:1. Key words: Standard length; Pre-dorsal length; Puntius chola; Morphomertric; Fish culture. DOI: 10.3329/bjsir.v45i4.7327 Bangladesh J. Sci. Ind. Res. 45(4), 309-314, 2010

scholarly journals SEBARAN UKURAN DAN BEBERAPA PARAMETER POPULASI HIU KARET (Prionace glauca Linnaeus, 1758) YANG TERTANGKAP DI PERAIRAN SELATAN NUSA TENGGARA

2017 ◽  
Vol 23 (2) ◽  
pp. 67
Author(s):  
Agus Arifin Sentosa ◽  
Umi Chodrijah ◽  
Irwan Jatmiko
Keyword(s):  
Sex Ratio ◽  
Size Distribution ◽  
Empirical Formula ◽  
Total Sample ◽  
Population Parameters ◽  
Optimum Length ◽  
Total Size ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Over Exploitation

Hiu karet (Prionace glauca) adalah hiu pelagis yang menjadi target tangkapan nelayan artisanal Tanjung Luar dan umumnya tertangkap di Samudera Hindia Selatan Nusa Tenggara. Penelitian ini bertujuan untuk mengetahui sebaran ukuran dan beberapa parameter populasi hiu karet (Prionace glauca) yang tertangkap di perairan selatan Nusa Tenggara. Analisis dilakukan terhadap 1.414 ekor hiu karet yang tertangkap rawai hanyut di selatan Nusa Tenggara dan didaratkan di Tanjung Luar, Lombok Timur selama periode 2014 – 2016. Analisis data dilakukan secara deskriptif dan beberapa parameter populasi diduga menurut rumus empiris Froese & Binohlan (2000). Hasil penelitian menunjukkan sebaran ukuran panjang total hiu karet berkisar antara 95 – 383 cm (jantan) dan 113 – 333 cm (betina) dengan rerata ukuran yang tertangkap tidak berbeda nyata. Nisbah kelamin didominasi oleh hiu karet jantan dan telah matang kelamin. Dugaan terhadap beberapa parameter adalah: nilai L∞ antara 333,02 - 385,59 cm dengan Lm jantan antara 187,21 – 215 cm dan betina 139,82 – 159,34 cm. Sebanyak 39,96 – 44,71% hiu karet tertangkap pada panjang optimumnya sehingga ada kecenderungan tangkap lebih.The blue shark (Prionace glauca) is targeted pelagic shark of artisanal fishermen of Tanjung Luar and commonly caught from the southern part of Nusa Tenggara water. The research aims to determine the size distribution and some population parameters of blue shark (Prionace glauca) caught in the Southern part of Nusa Tenggara water. The analysis was performed on 1,414 blue sharks caught by drifting longlines in the Southern part of Nusa Tenggara water and landed at Tanjung Luar, East Lombok during the period 2014 - 2016. The data were analyzed descriptively and some parameters of the population were calculated by the empirical formula from Froese & Binohlan (2000). The results showed that the length total size distribution of blue sharks ranged between 95-383 cm (male) and 113-333 cm (females). The sex ratio was dominated by male shark. The estimation of population parameters of shark were L∞ ranged between 333.02 - 385.59 cm, Lm estimated ranged between 187.21 to 215 cm (male) and from 139.82 to 159.34 cm (female). About 39.96 to 44.71% of total sample was caught at its optimum length, so it tends to be over exploitation. 

scholarly journals Aggressive interactions between juvenile swordfishes and blue sharks in the Western Mediterranean: a widespread phenomenon?

2019 ◽  
Vol 20 (2) ◽  
Author(s):  
JAIME PENADÉS-SUAY ◽  
PABLO GARCÍA-SALINAS ◽  
JESÚS TOMÁS ◽  
FRANCISCO JAVIER AZNAR
Keyword(s):  
Computed Tomography ◽  
Western Mediterranean ◽  
Defensive Strategy ◽  
Blue Shark ◽  
Prionace Glauca ◽  
X Ray ◽  
Aggressive Interactions ◽  
Open Questions ◽  
Widespread Phenomenon ◽  
The Right

There are numerous reports of billfishes spearing objects, marine organisms, and even humans. Whether or not this behaviour is intentional and, if so, what is its functional meaning, are open questions. In 2016, an adult blue shark (Prionace glauca) was found to be killed by a juvenile swordfish (Xiphias gladius) in the western Mediterranean. Here we report on three more recent cases involving both species in the same area. In February 2017, an adult male blue shark was found stranded in Garrucha (Spain) with a fragment of a juvenile swordfish’s rostrum (18cm long x 2cm wide at proximal end) inserted in its cranium. In March 2017, an adult pregnant female blue shark was stranded alive on the coast of Ostia (Italy) but died shortly afterwards; a fragment of a juvenile swordfish’s rostrum (25x3cm) was found allocated between the eye and the cranium. Finally, in February 2018, an adult female blue shark appeared stranded in the coast of Vera (Spain), with a putative impalement injury anterior to the right eye but without an associated bill fragment. Surprisingly, X-ray and computed tomography revealed an older injury in the right nostril, with a small piece of a juvenile swordfish’s rostrum (5.3x1.2cm). These cases suggest that juvenile swordfish would drive their rostrum into blue sharks as a defensive strategy that is likely to be far from anecdotal. We suggest that no regular cases of these interactions are reported because they occur at high sea and evidence of them, when available, can easily be overlooked.

Habitat specificity of the acanthocephalan Acanthocephalus clavula (Dujardin, 1845) in eels Anguilla anguilla (L)

1982 ◽  
Vol 56 (2) ◽  
pp. 121-130 ◽  
Author(s):  
C. R. Kennedy ◽  
D. Lord
Keyword(s):  
Sex Ratio ◽  
Alimentary Canal ◽  
Alimentary Tract ◽  
Sea Water ◽  
Anguilla Anguilla ◽  
Habitat Specificity ◽  
The Mean ◽  
Posterior Migration ◽  
Gravid Females ◽  
Single Worm

ABSTRACTThe habitat specificity of the acanthocephalan Acanthocephalus clavula in the alimentary tract of eels was studied in natural infections and in fish maintained experimentally under different regimes. The parasite exhibited a preference for a particular region (55 to 65%) of the alimentary canal which did not differ in different species of host, but habitat specificity was not very precise as there was considerable variation between individual hosts and A. clavula was capable of surviving and maturing in all regions of the intestine. The mean position of males was slightly anterior to that of females, and the over-all sex ratio was in favour of females. At high levels of infection the range of the parasites was extended and the mean position was significantly more anterior when compared to single worm infections. The parasite remains in the same site throughout the course of an infection: there was no posterior migration and gravid females occurred in the same proportion in all regions of the intestine. The mean position of the parasite did not change when the host was starved, or maintained in 100% sea water or with reduced aeration or at high temperatures. The results were compared with the habitat specificity exhibited by other species of freshwater fish acanthocephalans, and it was concluded that A. clavula was as adaptable and hardy as its present host, the eel.

scholarly journals On the Fecundity and Sex-ratio of Labeo bata (Hamilton) (Cypriniformes: Cyprinidae)

2015 ◽  
Vol 11 (2) ◽  
pp. 43-48
Author(s):  
MAR Joadder
Keyword(s):  
Body Weight ◽  
Sex Ratio ◽  
Average Length ◽  
Total Body Weight ◽  
Total Length ◽  
Labeo Bata ◽  
The Mean ◽  
Total Body ◽  
Gravid Females ◽  
The Relationship

The fecundity and sex- ratio of 2200 Labeo bata (Hamilton) specimens were studied. The fecundity of 234 gravid females varied from 51,354( for a fish with total length of 127.3 mm and total body weight of 20.0 g) to 91,568( for a fish with total length of 256.6 mm and total body weight of 156.70g).The mean fecundity was recorded as 67,617.50±13,510.15 for the average length and weight of 192.98±41.06 mm and 87.79±49.07 g, respectively .The mean total length and weight of gonad was 67.62± 24.01 mm and 20.35±13.50 g, respectively .The relationship between fecundity ( F.) and other parameters such as total length ( TL ), Standard length ( SL),  total weight( TW),  gonadal length (GL),  gonadal weight (GW) and gonadal depth (GD) were studied. DOI: http://dx.doi.org/10.3329/jsf.v11i2.21595 Journal of Science Foundation, 2013;11(2):43-48

Morphological ontogeny and ecology of Adoristes ovatus (Acari: Oribatida: Liacaridae), with comments on Adoristes Hull

2017 ◽  
Vol 22 (12) ◽  
pp. 2038 ◽  
Author(s):  
Anna Seniczak ◽  
Stanisław Seniczak ◽  
Sławomir Kaczmarek ◽  
Bogusław Chachaj
Keyword(s):  
Sex Ratio ◽  
Cross Section ◽  
Body Length ◽  
Junior Synonym ◽  
Thin Line ◽  
Anal Opening ◽  
The Mean ◽  
Gravid Females

The morphological ontogeny of Adoristes ovatus (C.L. Koch, 1839) is described and illustrated. The adult has the interlamellar seta shorter than the lamella and the translamella is usually absent, but can also be incomplete, or present as a thin line. The juveniles are unpigmented, oval in cross-section, with thin and smooth prodorsal and gastronotal setae, and with the anal opening in the posteroventral position, which is typical of xylophages. The legs and claws of juveniles are relatively thick, especially leg I, and the leg setae are smooth or with short barbs. All juveniles have a sclerotized semicircle located anterior to each prodorsal seta le. The larva has 11 pairs of gastronotal setae, the nymphs have 12 pairs, without the d-series. The mean body length of females is larger than males, but varies greatly among samples (445–735 μm) and the largest females can be 1.5 times longer than the smallest males. The sex ratio and the number of gravid females also vary among samples. We provisionally consider Adoristes (Gordeeviella) Shtanchaeva, Subías & Arillo, 2010 a junior synonym of Adoristes Hull, 1916.

scholarly journals Demographic and Exploitation Parameters of the Blue Shark, Prionace Glauca in the Gulf of Guinea (Togo-Benin-Nigeria)

2020 ◽  
Author(s):  
Houangninan Emmanuel Calèbe Midinoudéwa ◽  
Zacharie Sohou ◽  
Samuel Kofi Tulashie ◽  
Emile Didier Fiogbé
Keyword(s):  
Total Mortality ◽  
Demographic Parameters ◽  
Gulf Of Guinea ◽  
Effective Management ◽  
Artisanal Fishing ◽  
Marine Waters ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Management Measures ◽  
First Maturity

Prionace glauca, blue shark is a cosmopolitan species. Together with Carcharhinus falciformis, it co-dominated the landings of carcharhinidae sharks at the Artisanal Fishing Port of Cotonou. The objective of this study is to determine the demographic parameters of the blue shark in Gulf of Guinea marine waters. The different routines of the FISAT II v 1.2 software associated with the empirical equations of Froese and Nohland, allowed the evaluation of the different demographic parameters of the blue shark in Benin's marine waters. From August to December 2015, 244 individuals shark sizes; ranging from 175cm to 325cm were sampled. The total asymptotic length obtained was 341.25cm with a growth rate of 0.35/year, which indicates that the species is growing rapidly and the optimal total length of the species is 232.01cm. The age of first maturity of the species is 3 years with a longevity of 10 years. The exploitation rate is E= 0.74 with total mortality being 2.4; natural mortality is 0.6 and fishing mortality is 1.8. The sex ratio remains in favour of males throughout the study period. Monitoring programme were suggested with effective management measures established and executed for sustainability of the blue shark’s stock in the Gulf of Guinea.

Relationships of Female Age and Size to Embryo Number and Size in the Shiner Perch, Cymatogaster aggregata

1969 ◽  
Vol 26 (9) ◽  
pp. 2339-2344 ◽  
Author(s):  
Dennis C. Wilson ◽  
Raymond E. Millemann
Keyword(s):  
Fork Length ◽  
Correlation Coefficients ◽  
Female Parent ◽  
Female Age ◽  
Embryo Number ◽  
Gravid Females ◽  
Relationship Of ◽  
The Relationship ◽  
Parent Female ◽  
Female Weight

Ages, lengths, and weights were determined for 124 female shiner perch, Cymatogaster aggregata Gibbons, collected in Yaquina Bay, Oregon, from May 17 through June 29, 1968. Embryos (1005) were obtained from 111 gravid females either by dissection (737) or at parturition in the laboratory (268). Embryo lengths, weights, and numbers per female parent were determined.As females increased in age from 1 to 6 years, their mean fork length increased from 9.32 to 13.65 cm, their weight from 13.65 to 47.78 g, and the mean number of embryos per parent female increased from 5.83 to 20.00. The equations and their correlation coefficients (R) computed for the relationships of embryo number (Y) to parent female fork length, weight, and age are, respectively: log Y = −1.892 + 2.735 log X (R = 0.89); Y = 1.131 + 0.313 X (R = 0.70); and Y = 4.23 + 1.73 X (R = 0.51). Embryo size at birth was also directly related to female parent size. The equations computed for the relationships of total length of embryo at birth (Y) to parent female fork length and parent female weight are, respectively: Y = 24.211 + 1.620 X (R = 0.79); and Y = 0.384 + 0.015 X (R = 0.72). The equation computed for the relationship of embryo weight (Y) to embryo length at birth is Y = −2.266 + 0.712 X (R = 0.95).

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