Geographic variation in reproduction between two populations of the bonnethead shark, Sphyrna tiburo

Parsons, Glenn R.

doi:10.1007/978-94-017-3450-9_3

Cited by 59 publications

(82 citation statements)

References 4 publications

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“…In this study, the females and males were found to be mature at a larger size, compared to previous studies and it is possible that differences could have resulted from distinctive oceanographic conditions in the region, or fisheries influence, regional differences, or sampling difference which could cause differences in biological parameters between populations, such as maximum size, growth rate, size-at-maturity and fecundity (Parsons, 1993;Lombardi-Carlson et al, 2003;Motta, et al, 2007). Size at birth estimated in the study was 25-30 cm TL which was larger than those reported (as 21-26 cm TL) earlier by Appukuttan and Nair (1988).…”

Section: Length-weight Relationshipscontrasting

confidence: 54%

Reproductive biology and diet of the grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhinidae) from the north-eastern Arabian Sea

et al. 2017

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Information on reproductive biology is presented for the grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhiniformes), collected off the north-west coast of India in the Arabian Sea. A total of 711 individuals, of 27.0 to 93.0 cm total length (TL), 180 to 2600 g total weight (TW) were used for the study. The lengthweight relationships were significantly different between the sexes. The size-at-maturity (Lm 50 ) for females and males was estimated to be 62.3 and 59.5 cm TL respectively. Number of embryos ranged from 1 to 7 and the size at birth was estimated between 25 to 30 cm TL. Overall sex ratio favoured the females slightly at the rate of 1.27:1. There was significant positive correlation between maternal TL and number of embryos (p<0.001). Dietary analysis of stomach contents (%IRI) revealed that R. oligolinx feeds primarily on teleosts (95.5%), cephalopods (3.2%) and crustaceans (1.2%). This study presents the first detailed biological observation on size, sex composition, size-at-maturity (Lm 50 ) and length-weight relationship of R. oligolinx from the northern Arabian Sea.

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Section: Length-weight Relationshipscontrasting

confidence: 54%

Reproductive biology and diet of the grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhinidae) from the north-eastern Arabian Sea

et al. 2017

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“…These differences may be attributable to differences in the methods for assessing maturity and/or in sample size used in each study. Another possible explanation, taking into account that C. callorynchus has a widely distribution off southern South America, is that perhaps there are multiple discrete populations of this species with latitudinal variation in size at maturity, as was suggested for several chondrichthyan species around the world (Templeman, 1987;Parsons, 1993;Lucifora et al, 1999;Chiaramonte, Petovello, 2000;Mabragaña, Cousseau, 2004;Colonello et al, 2007;Ebert et al, 2008;Barnett et al, 2009). In turn, the PCL 50 estimated in the study area was lower than those values found in northern Patagonian waters, which may be associated with the fact that coastal waters of south-eastern Buenos Aires Province support the highest pressure on chondrichthyans in Argentina (Massa et al, 2004).…”

Section: Discussionmentioning

confidence: 96%

Reproductive biology of the cockfish, Callorhinchus callorynchus (Chondrichthyes: Callorhinchidae), in coastal waters of the northern Argentinean Sea

et al. 2017

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The cockfish, Callorhinchus callorynchus, is a widely distributed holocephalan in the south-western Atlantic and an important resource for Argentinean fisheries. The reproductive characteristics of this species were studied in northern Argentinean coastal waters, where specimens arrive seasonally (winter-spring). Sexual dimorphism in maximum precaudal length (PCL) and total body mass (TM) was found, being females (PCL=630 mm; TM=3330 g; n=167) larger and heavier than males (PCL=482 mm; TM=1630 g; n=19). Maturity size for females was 466.22 mm PCL, representing 74% PCL of the largest female sampled. The mean number of ovarian follicles was 8.37 (± 4.84). The highest values of ovarian follicles diameter, gonadosomatic and oviducalsomatic indices were found in spring. A high proportion of mature females (44%) had atretic ovarian follicles, suggesting that they were in the resting stage of their reproductive cycle. The low number of mature males recorded and the absence of mature females with spermatophore masses or egg cases indicate that the study area would not be a reproductive zone. The seasonal presence of C. callorynchus in this region could be related to trophic movements. These results, obtained in an area with high fishing pressure on chondrichthyans, will be useful for implementing conservation and management measures.Keywords: Holocephalans, Maturity, Ovarian fecundity, Seasonality, South-western Atlantic.El pez gallo, Callorhinchus callorynchus, es un holocéfalo con amplia distribución en el Atlántico Sudoccidental y un recurso importante para las pesquerías en Argentina. Las características reproductivas de esta especie fueron estudiadas en aguas costeras al norte del Mar Argentino, adonde se acercan estacionalmente (invierno-primavera). Se observó dimorfismo sexual en los valores máximos de longitud precaudal (LPC) y masa corporal total (MT), siendo las hembras (LPC=630 mm; MT=3330 g; n=167) más grandes y pesadas que los machos (LPC=482 mm; MT=1630 g; n=19). La talla de maduración para las hembras fue de 466,22 mm LPC, representando el 74% de la LPC máxima observada. El número promedio de folículos ováricos fue 8,37 (± 4,84). Los valores más altos del diámetro de los folículos ováricos, índice de la glándula oviductal e índice gonadosomático fueron hallados durante primavera. Una gran proporción de hembras maduras (44%) presentaron folículos ováricos atrésicos, sugiriendo que se encontraban en la etapa de reposo de su ciclo reproductivo. El bajo número de machos maduros registrados y la ausencia de hembras maduras con espermatóforos o cápsulas de huevos indican que las aguas costeras del norte de Argentina no serían una zona reproductiva. La presencia de C. callorynchus en el área de estudio podría estar relacionada con movimientos tróficos. Los resultados, obtenidos en un área con una gran presión pesquera sobre los condrictios, serán útiles para implementar adecuados planes de manejo y conservación de esta especie.

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“…Researchers have speculated that this short opportunistic window evolved to maximize the reproductive success of these species by increasing the survival of the young (Castro 2009). Despite the general acceptance of this view of carcharhinid reproductive strategy, the information on which it is based has been obtained from only a few species, largely ones from the temperate waters of the western North Atlantic Ocean, including the Atlantic Sharpnose Shark (Parsons 1983;Loefer and Sedberry 2003), Blacktip Shark Carcharhinus limbatus (Castro 1996), Finetooth Shark (Castro 1993), Blacknose Shark (Driggers et al 2004;Sulikowski et al 2007), Sandbar Shark C. plumbeus (Baremore and Hale 2012), and Bonnethead Sphyrna tiburo (Parsons 1993). In addition, several of these studies have lacked sample sizes and intervals adequate to fully assess the potential reproductive patterns and/or anomalies that could exist within a population.…”

Section: Discussionmentioning

confidence: 99%

Variability in the Reproductive Cycle of Finetooth Sharks, Carcharhinus isodon, in the Northern Gulf of Mexico

Driggers¹,

Hoffmayer²

2009

Copeia

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Geographic variation in reproduction between two populations of the bonnethead shark, Sphyrna tiburo

Cited by 59 publications

References 4 publications

Reproductive biology and diet of the grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhinidae) from the north-eastern Arabian Sea

Reproductive biology and diet of the grey sharpnose shark Rhizoprionodon oligolinx Springer, 1964 (Chondrichthyes: Carcharhinidae) from the north-eastern Arabian Sea

Reproductive biology of the cockfish, Callorhinchus callorynchus (Chondrichthyes: Callorhinchidae), in coastal waters of the northern Argentinean Sea

Variability in the Reproductive Cycle of Finetooth Sharks, Carcharhinus isodon, in the Northern Gulf of Mexico

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