The milk shark, Rhizoprionodon acutus (Rueppel, 1837), is the shark species most abundantly landed at fishing sites along the Senegalese coast in the eastern tropical Atlantic. Adult males and ...females were mainly captured from March to September. The smallest adult male was 840 mm total length (TL) and weighed 2650 g; all males above 950 mm TL were adult. The smallest adult female was 890 mm TL and 4800 g; all females above 1000 mm were adult. The largest male and female were 1215 mm and 1260 mm TL and 6700 g and 6830 g, respectively. There was a significant difference in the total mass vs. TL relationship between males and females. Parturition and mating occurred in May and June. Gestation lasted approximately one year. Females had an annual reproductive cycle although some reproduced in alternate years. The diameter and mass of the largest yolked oocytes ranged 20-23 mm (mean 21.2 plus or minus 0.9) and 4.1-5.6 g (mean 4.8 plus or minus 0.5). Both uteri were compartmentalized into chambers with a single embryo in each chamber. Size and mass at birth, based on term embryos and neonates, ranged 325-500 mm TL (mean 391.4 plus or minus 24.4) and 127-350 g (mean 220.7 plus or minus 37.9). A chemical balance of development based on mean dry mass of the largest yolked oocytes and term embryos was 23. Ovarian fecundity was slightly higher than uterine fecundity. There was a slight positive relationship between uterine fecundity and female TL, but not between ovarian fecundity and female TL. Litter sizes ranged from one to eight (mean 3.5 plus or minus 1.3) with males and females equally distributed. In free-swimming specimens, females significantly outnumbered males, especially among sub-adult and adult specimens.Original Abstract: Morski pas, Rhizoprionodon acutus (Rueppel, 1837), je najvise rasprostranjen na ribarskim postajama duz senegalske obale istocnog dijela tropskog Atlantika. Odrasli muzjaci i zenke su pretezito lovljeni od ozujka do rujna. Ukupna duljina (TL) najmanjeg primjerka muzjaka iznosila je 840 mm, a tezina 2650 g, dok su svi odrasli muzjaci bili duzi od 950 mm TL. Najmanja odrasla zenka bila je duga 890 mm TL i teska 4800 g, a sve odrasle zenke bile su duze od 1000 mm. Najveci primjerak muzjaka bio je dug 1215 mm i tezak 6700 g, a najveci primjerak zenke bio je 1260 mm dug i 6830 g tezak. Ustanovljena je statisticki znacajna razlika izmedju odnosa mase i ukupne duljine (TL) kod muzjaka i zenki. Parenje i porod se odvijaju u svibnju i lipnju. Trudnoca je trajala oko godinu dana. Zenke su imale godisnji reproduktivni ciklus iako su se neke razmnozavale u naizmjenicnim godinama. Promjer najvece oocite sa zumanjcem iznosio je 20-23 mm (prosjek 21.2 plus or minus 0.9), a tezina je kolebala izmedju 4.1-5.6 g (prosjek 4.8 plus or minus 0.5). Oba uterusa bila su podijeljena u komorice i u svakoj od komorica razvijao se po jedan embrij. Duzina i tezina kod rodjenja, mjerena na embrijima i novorodjenim primjercima procijenjene su na 325-500 mm TL (prosjek 391.4 plus or minus 24.4) i 127-350 g (prosjek 220.7 plus or minus 37.9). Kemijska ravnoteza razvoja, temeljena na prosjecnoj suhoj tezini najvecih oocita sa zumanjcem i embrijima bliskog vremenskog razdoblja, bila je 23. Ovarijska plodnost bila je veca od uterine plodnosti. Ustanovljen je pozitivni odnos izmedju uterine plodnosti i ukupne duljine zenki, ali takav odnos nije ustanovljen kod ovarijske plodnosti i ukupne duljine (TL). Velicine izlegnutih mladih kolebale su od 1 do 8 (prosjek 3.5 plus or minus 1.3) podjednako kod muzjaka i zenki. Opcenito je bilo vise zenki nego muzjaka, narocito medju slobodno plivajucim odraslim primjercima.
The smoothhound shark, Mustelus mustelus (Linnaeus, 1758), is commonly landed at fishing sites along the Senegalese coast (eastern tropical Atlantic). Adult males and females are captured mainly in ...spring and summer. The smallest male adult was 82 cm TL and weighed 1.85 kg. Males were all adults by 95 cm TL. The smallest female adult was 90 cm TL and weighed 3 kg. Females were all adults by 104 cm. The largest male and the largest female were 139 cm and 150 cm TL, and weighed 11 kg and 8.1 kg. However, the heaviest female weighed 13.85 kg and was 145 cm TL. There was no significant relationship between total mass and TL between males and females. Mating probably occurred in spring and early summer, as did parturition. Gestation lasted approximately one year. Females had an annual reproductive cycle, although some females reproduce in alternate years. Diameters of the largest yolky oocytes ranged from 20 to 23 mm (mean 20.7 plus or minus 3.4) and their masses from 3.6 to 4.9 g (mean: 4.2 plus or minus 0.3). Both uteri were compartmentalized into chambers during part of the pregnancy, with a single embryo in each chamber. Size and mass at birth, based on term embryos and neonates ranged from 36 to 45 cm TL (mean: 40.31 plus or minus 1.72) and from 150 to 256 g (mean: 199.9 plus or minus 20.7). In order to show the role of mother during embryonic development, a chemical balance of development was calculated, it was based on mean dry masses of the largest yolky oocytes and term embryos was 24. Ovarian fecundity is slightly higher than uterine fecundity. Litter sizes ranged from four to 21 (mean: 9.2 plus or minus 3.9), and there was a slight positive relation between litter size and total length of females. In free-swimming specimens, only sub-adult females significantly outnumbered the male ones.Original Abstract: Biologie de la reproduction de l'emissole lisse, Mustelus mustelus (Chondrichthyes: Carcharhinidae) de la cote du Senegal (Atlantique oriental tropical). L'emissole lisse, Mustelus mustelus (Linnaeus, 1758) est une espece de requin abondamment debarquee sur les sites de peche situes au long de la cote senegalaise (Atlantique oriental tropical). Des males et femelles adultes sont generalement captures au printemps et en ete. Le plus petit male adulte mesurait 82 cm de longueur totale (LT) et pesait 1,85 kg. Au-dessus de 95 cm LT, tous les males observes etaient adultes. La plus petite femelle adulte mesurait 90 cm de longueur totale (LT) et pesait 3 kg. Au-dessus de 104 cm LT, toutes les femelles observees etaient adultes. Les plus grands adultes male et femelle mesuraient respectivement 139 cm et 150 cm LT et pesaient respectivement 11 kg et 8,1 kg. Toutefois, la plus lourde femelle pesait 13,85 kg et mesurait 145 cm LT. Il n'y a pas de relation significative taille-masse entre males et femelles. L'accouplement et la parturition ont lieu au printemps et au debut de l'ete. La gestation dure approximativement une annee. Les femelles ont un cycle de reproduction annuel, bien que certaines femelles se reproduisent une annee sur deux. Les diametres des plus grands ovocytes riches en vitellus sont compris entre 20 et 23 mm (moyenne : 20,7 plus or minus 3,4) et leurs masses entre 3,6 et 4,9 g (moyenne : 4,2 plus or minus 0,3). Les deux uterus sont compartimentes en chambre et dans chacune d'elles un unique embryon se developpe. La taille et la masse a la naissance, fondees sur les embryons a terme se situent entre 36 et 45 cm (moyenne : 40,31 plus or minus 1,72) et de 150 a 256 g. Dans le but de mettre en evidence le role de la mere pendant le developpement embryonnaire, une balance chimique de developpement a ete calculee; elle est fondee sur les masses seches moyennes des plus grands ovocytes et des embryons a terme et egale a 24. La fecondite ovarienne est sensiblement superieure a la fecondite uterine. Les portees varient de quatre a vingt et un (moyenne : 9,2 plus or minus 3,9); parmi les individus libres, il y a une faible correlation positive entre le nombre d'individus par portees et la longueur totale des femelles. Parmi les individus libres, seul les femelles subadultes sont significativement plus nombreuses que les males.
The Atlantic weasel shark, Paragaleus pectoralis (Garman, 1906), is the only species of the genus Paragaleus to be recorded off the western coast of Africa. It is commonly landed at the fishing sites ...along the Senegalese coast. Adult males and females are mostly captured in spring and summer. The smallest male and female adults were 810 mm and 900 mm total length (TL), respectively. The largest male and the largest female adults were 1.32 m and 1.38 m TL, respectively, and weighed 7.55 kg and 11 kg, respectively. There was no significant difference for total mass and TL relationship between males and females. Mating occurred from March to May, and parturition in May and June. Gestation lasted approximately one year. Females had biennial or triennial reproductive cycle. Vitellogenesis did not occur while females were pregnant. Diameter of the largest yolky oocytes ranged from 25 to 31 mm (mean: 28.6 plus or minus 2.6) and their mass from 8.8 to 9.9 g (mean: 9.4 plus or minus 0.5). Both uteri were compartmentalized into chambers, with a single embryo in each chamber. Size and mass at birth, based on near-term embryos were between 390-500 mm TL and 214-407 g, respectively. A chemical balance of development based on mean dry masses of the largest yolky oocytes and the fully developed embryos was 14.8. Ovarian fecundity was slightly higher than uterine fecundity. There was a slight positive correlation between uterine fecundity and female TL, not between ovarian fecundity and female TL. Litter sizes ranged from two to seven (mean: 4.6 plus or minus 1.6) with males outnumbering females.Original Abstract: Le milandre jaune, Paragaleus pectoralis (Garman, 1906), est l'unique espece du genre Paragaleus signalee au large de la cote ouest de l'Afrique. Elle est communement debarquee sur les sites de peche situes au long du littoral senegalais, et les captures concernent surtout des males et femelles adultes rapportes au printemps et en ete. Les plus petits adultes male et femelle mesuraient respectivement 810 mm et 900 mm de longueur totale (LT). Les plus grands adultes male et femelle mesuraient respectivement 1,32 m et 1,38 m LT et pesaient respectivement 7,55 kg et 11 kg. Il n'y a pas de relation significative taille-masse entre males et femelles. L'accouplement a lieu de mars a mai, et la parturition en mai et juin. La gestation dure approximativement une annee. Les femelles ont un cycle de reproduction bisannuel ou trisannuel. La vitellogenese ne se deroule pas en meme temps que la gestation. Le diametre des plus grands ovocytes riches en vitellus est compris entre 25 et 31 mm (moyenne : 28,6 plus or minus 2,6) et leur masse entre 8,8 et 9,9 g (moyenne: 9,4 plus or minus 0,5). Les deux uterus sont compartimentes en chambres et dans chacune d'elles un unique embryon se developpe. La taille et la masse a la naissance, fondees sur les embryons a terme, se situent entre 390-500 mm et 214-407 g. Une balance chimique de developpement fondee sur les masses seches moyennes des plus grands ovocytes et des embryons a terme est egale a 14,8. Il y a une faible relation positive entre la fecondite et la LT des femelles. En revanche, il n'y a pas de relation entre la fecondite uterine et la LT des femelles. Les portees varient de deux a sept (moyenne: 4,6 plus or minus 1,6). Parmi les deux categories d'embryons, les males sont significativement plus nombreux que les femelles.
Four pregnant females were captured by commercial gill-nets from October 1994 to August 1996 at the site of Ouakam, located 5 km from Dakar, in the Cape Verde Peninsula. The authors describe their ...ovarian and uterine contents.
Two torpedinids belonging to the subgenus Tetronarce Gill, 1862 are recorded off the coast of Senegal (Cadenat, 1950; Seret and Opic, 1990): the electric ray, Torpedo (Tetronarce) nobiliana ...Bonaparte, 1835 and the Mackay's torpedo ray, T. (Tetronarce) mackayana Metzelaar, 1919. The former is rarely caught in the area, while the latter is sometimes landed, permitting us to prescrit some data on its reproductive biology.Original Abstract: Des observations biologiques relatives a la torpille de Mackay, Torpedo (Tetronarce) mackayana, sont rapportees a partir de 78 specimens captures au large de la cote du Senegal: taille de premiere maturite sexuelle des males et des femelles, diametre et masse des ovocytes, periode d'activite vitellogenetique, duree de la gestation, fecondites ovarienne et uterine. T (Tetronarce) mackayana est une espece lecithotrophe. L'espece n'est pas prolifique et les deux types de fecondite sont en relation avec la taille des femelles. Parmi les embryons, les foetus et les juveniles, les males sont plus abondants que les femelles. On observe le phenomene inverse chez les adultes.
The milk shark, Rhizoprionodon acutus (Rüppel, 1837), is the shark species most abundantly landed at fishing sites along the Senegalese coast in the eastern tropical Atlantic. Adult males and females ...were mainly captured from March to September. The smallest adult male was 840 mm total length (TL) and weighed 2650 g; all males above 950 mm TL were adult. The smallest adult female was 890 mm TL and 4800 g; all females above 1000 mm were adult. The largest male and female were 1215 mm and 1260 mm TL and 6700 g and 6830 g, respectively. There was a significant difference in the total mass vs. TL relationship between males and females. Parturition and mating occurred in May and June. Gestation lasted approximately one year. Females had an annual reproductive cycle although some reproduced in alternate years. The diameter and mass of the largest yolked oocytes ranged 20-23 mm (mean 21.2±0.9) and 4.1-5.6 g (mean 4.8±0.5). Both uteri were compartmentalized into chambers with a single embryo in each chamber. Size and mass at birth, based on term embryos and neonates, ranged 325-500 mm TL (mean 391.4±24.4) and 127-350 g (mean 220.7±37.9). A chemical balance of development based on mean dry mass of the largest yolked oocytes and term embryos was 23. Ovarian fecundity was slightly higher than uterine fecundity. There was a slight positive relationship between uterine fecundity and female TL, but not between ovarian fecundity and female TL. Litter sizes ranged from one to eight (mean 3.5±1.3) with males and females equally distributed. In free-swimming specimens, females significantly outnumbered males, especially among sub-adult and adult specimens.
Morski pas, Rhizoprionodon acutus (Rüppel, 1837), je najviše rasprostranjen na ribarskim postajama duž senegalske obale istočnog dijela tropskog Atlantika. Odrasli mužjaci i ženke su pretežito lovljeni od ožujka do rujna. Ukupna duljina (TL) najmanjeg primjerka mužjaka iznosila je 840 mm, a težina 2650 g, dok su svi odrasli mužjaci bili duži od 950 mm TL. Najmanja odrasla ženka bila je duga 890 mm TL i teška 4800 g, a sve odrasle ženke bile su duže od 1000 mm. Najveći primjerak mužjaka bio je dug 1215 mm i težak 6700 g, a najveći primjerak ženke bio je 1260 mm dug i 6830 g težak. Ustanovljena je statistički značajna razlika između odnosa mase i ukupne duljine (TL) kod mužjaka i ženki. Parenje i porod se odvijaju u svibnju i lipnju. Trudnoća je trajala oko godinu dana. Ženke su imale godišnji reproduktivni ciklus iako su se neke razmnožavale u naizmjeničnim godinama. Promjer najveće oocite sa žumanjcem iznosio je 20-23 mm (prosjek 21.2±0.9), a težina je kolebala između 4.1-5.6 g (prosjek 4.8±0.5). Oba uterusa bila su podijeljena u komorice i u svakoj od komorica razvijao se po jedan embrij. Dužina i težina kod rođenja, mjerena na embrijima i novorođenim primjercima procijenjene su na 325-500 mm TL (prosjek 391.4±24.4) i 127-350 g (prosjek 220.7±37.9). Kemijska ravnoteža razvoja, temeljena na prosječnoj suhoj težini najvećih oocita sa žumanjcem i embrijima bliskog vremenskog razdoblja, bila je 23. Ovarijska plodnost bila je veća od uterine plodnosti. Ustanovljen je pozitivni odnos između uterine plodnosti i ukupne duljine ženki, ali takav odnos nije ustanovljen kod ovarijske plodnosti i ukupne duljine (TL). Veličine izlegnutih mladih kolebale su od 1 do 8 (prosjek 3.5±1.3) podjednako kod mužjaka i ženki. Općenito je bilo više ženki nego mužjaka, naročito među slobodno plivajućim odraslim primjercima.
Morski pas, Rhizoprionodon acutus (Rüppel, 1837), je najviše rasprostranjen na ribarskim postajama duž senegalske obale istočnog dijela tropskog Atlantika. Odrasli mužjaci i ženke su pretežito ...lovljeni od ožujka do rujna. Ukupna duljina (TL) najmanjeg primjerka mužjaka iznosila je 840 mm, a težina 2650 g, dok su svi odrasli mužjaci bili duži od 950 mm TL. Najmanja odrasla ženka bila je duga 890 mm TL i teška 4800 g, a sve odrasle ženke bile su duže od 1000 mm. Najveći primjerak mužjaka bio je dug 1215 mm i težak 6700 g, a najveći primjerak ženke bio je 1260 mm dug i 6830 g težak. Ustanovljena je statistički značajna razlika između odnosa mase i ukupne duljine (TL) kod mužjaka i ženki. Parenje i porod se odvijaju u svibnju i lipnju. Trudnoća je trajala oko godinu dana. Ženke su imale godišnji reproduktivni ciklus iako su se neke razmnožavale u naizmjeničnim godinama. Promjer najveće oocite sa žumanjcem iznosio je 20-23 mm (prosjek 21.2±0.9), a težina je kolebala između 4.1-5.6 g (prosjek 4.8±0.5). Oba uterusa bila su podijeljena u komorice i u svakoj od komorica razvijao se po jedan embrij. Dužina i težina kod rođenja, mjerena na embrijima i novorođenim primjercima procijenjene su na 325-500 mm TL (prosjek 391.4±24.4) i 127-350 g (prosjek 220.7±37.9). Kemijska ravnoteža razvoja, temeljena na prosječnoj suhoj težini najvećih oocita sa žumanjcem i embrijima bliskog vremenskog razdoblja, bila je 23. Ovarijska plodnost bila je veća od uterine plodnosti. Ustanovljen je pozitivni odnos između uterine plodnosti i ukupne duljine ženki, ali takav odnos nije ustanovljen kod ovarijske plodnosti i ukupne duljine (TL). Veličine izlegnutih mladih kolebale su od 1 do 8 (prosjek 3.5±1.3) podjednako kod mužjaka i ženki.
Općenito je bilo više ženki nego mužjaka, naročito među slobodno plivajućim odraslim primjercima.
