Size and sex compositions, length–weight relationship, and occurrence of the Brazilian sharpnose shark, Rhizoprionodon lalandii, caught by artisanal fishery from southeastern Brazil

Motta, Fábio S.; Gadig, Otto Bismarck Fazzano; Namora, Rafael Cabrera; Braga, F.M.S

doi:10.1016/j.fishres.2005.03.010

Cited by 56 publications

(73 citation statements)

References 23 publications

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“…Furthermore, R. oligolinx from this study attained a greater maximum size (93.0 cm TL) than previously reported from elsewhere (80 cm TL by Abdul Nizar et al, 1988; 70 cm TL by Compagno et al, 2005; 85 cm TL by Moore et al, 2012). The difference detected between size-frequency distributions of females and males is probably a consequence of sexual segregation, a general characteristic of shark populations that is normally associated with reproduction, migration or competition (Springer, 1967;Klimley, 1987;Stevens and Mcloughlin, 1991;Motta et al, 2005).…”

Section: Length-weight Relationshipssupporting

confidence: 46%

“…The differences could be the result of several factors like fishing gear selectivity and/or sample size, regional differential growth based on habitat (Motta et al, 2005). Furthermore, R. oligolinx from this study attained a greater maximum size (93.0 cm TL) than previously reported from elsewhere (80 cm TL by Abdul Nizar et al, 1988; 70 cm TL by Compagno et al, 2005; 85 cm TL by Moore et al, 2012).…”

Section: Length-weight Relationshipscontrasting

confidence: 42%

“…Females appear to be more vulnerable to fishing than males. Unequal sex ratios in sharks can be the result of sexual segregation by depth or area, gear selectivity or possibly even a natural phenomenon (Motta et al, 2005).…”

Section: Length-weight Relationshipsmentioning

confidence: 99%

“…The length-weight relationships (TL vs. TW) of R. oligolinx were significantly different between the sexes, indicating considerable ontogenetic weight increase in females (b>3) than in males (b<3) (Lessa, 1988;Motta, et al, 2005). According to Stevens and Wiley (1986), these variations between length-weight relationships of females and males may be a result of different sample sizes, an unequal distribution of sizes within each data set of each sex or even of non-pregnant females being lighter due to the inclusion of spent fish, which have a lower condition factor.…”

Section: Length-weight Relationshipsmentioning

confidence: 99%

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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 Relationshipssupporting

confidence: 46%

Section: Length-weight Relationshipscontrasting

confidence: 42%

Section: Length-weight Relationshipsmentioning

confidence: 99%

Section: Length-weight Relationshipsmentioning

confidence: 99%

See 2 more Smart Citations

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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“…However, despite generally high fecundity, these small sharks are under some pressure from overfishing in Brazil, where R. lalandii is listed as locally 'Vulnerable' due to intense harvest of all size and age classes in artisanal gillnet fisheries (Rosa et al, 2004;Motta et al, 2005Motta et al, , 2007. Rhizoprionodon lalandii made up 83% of the samples from Guyanese fish markets.…”

Section: Discussionmentioning

confidence: 99%

DNA barcoding reveals the diversity of sharks in Guyana coastal markets

et al. 2017

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A fundamental challenge for both sustainable fisheries and biodiversity protection in the Neotropics is the accurate determination of species identity. The biodiversity of the coastal sharks of Guyana is poorly understood, but these species are subject to both artisanal fishing as well as harvesting by industrialized offshore fleets. To determine what species of sharks are frequently caught and consumed along the coastline of Guyana, we used DNA barcoding to identify market specimens. We sequenced the mitochondrial co1 gene for 132 samples collected from six markets, and compared our sequences to those available in the Barcode of Life Database (BOLD) and GenBank. Nearly 30% of the total sample diversity was represented by two species of Hammerhead Sharks (Sphyrna mokarran and S. lewini), both listed as Endangered by the International Union for Conservation of Nature (IUCN). Other significant portions of the samples included Sharpnose Sharks (23% -Rhizoprionodon spp.), considered Vulnerable in Brazilian waters due to unregulated gillnet fisheries, and the Smalltail Shark (17% -Carcharhinus porosus). We found that barcoding provides efficient and accurate identification of market specimens in Guyana, making this study the first in over thirty years to address Guyana's coastal shark biodiversity.Keywords: BOLD, Carcharhinidae, Elasmobranch, Guianas, Sphyrnidae.Um desafio fundamental para a pesca sustentável e a proteção da biodiversidade nos neotrópicos é a identificação precisa das espécies. A biodiversidade dos tubarões costeiros da Guiana é pouco compreendida, porém essas espécies estão sujeitas tanto à pesca artesanal quanto à pesca industrializada não costeira. Para determinar quais espécies de tubarões são frequentemente capturadas e consumidas ao longo do litoral da Guiana, utilizamos DNA barcoding para identificar espécimes comumente encontrados e adquiridos em mercados. Nós sequenciamos o gene mitocondrial coI para 132 espécimes adquiridos de seis mercados e comparamos estas sequências com as disponíveis no Barcode of Life Database (BOLD) e GenBank. Quase 30% da diversidade total amostrada foi constituída por duas espécies de tubarões martelo (Sphyrna mokarran e S. lewini), ambas listadas como espécies ameaçadas pela UICN. Outras porções significativas da amostragem incluem Cações-Frango (23% -Rhizoprionodon spp.), considerados vulneráveis em águas brasileiras, devido a pesca de arrasto não regulamentada, e o Cação-azeiteiro (17% -Carcharhinus porosus). Descobrimos que o barcoding é uma forma identificação eficiente e precisa para espécimes de mercado na Guiana, tornando este estudo o pioneiro na documentação da biodiversidade dos tubarões costeiros da Guiana.

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Diversity and genetic population structure of the Brazilian sharpnose shark Rhizoprionodon lalandii

Mendonça

Oliveira

Gadig

et al. 2013

Aquatic Conservation

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1. Similar to many small, range-restricted elasmobranchs, the Brazilian sharpnose shark (Rhizoprionodon lalandii) is listed as 'data deficient' by the International Union for the Conservation of Nature (IUCN). Data on stock assessment and sustainability are scarce, and there is no information on population structure. This constitutes a management problem because this shark comprises approximately 50% of the catch of small coastal sharks in Brazil.2. In this study, populations of R. lalandii distributed from the Caribbean to southern Brazil were investigated using sequences from the mitochondrial DNA control region. Analysis of molecular variance revealed strong structuring between population samples from the Caribbean and those from the Brazilian coast (Ф ST = 0.254, P < 0.0001). Significant differences in the rates of genetic diversity between these major areas were also detected. The observed levels of population structuring are likely to be driven by female phylopatry.3. Therefore, the identification of both mating and nursery areas with parallel ban/restriction of fishing in these areas may be critical for the long-term sustainability of these populations.

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Size and sex compositions, length–weight relationship, and occurrence of the Brazilian sharpnose shark, Rhizoprionodon lalandii, caught by artisanal fishery from southeastern Brazil

Cited by 56 publications

References 23 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

DNA barcoding reveals the diversity of sharks in Guyana coastal markets

Diversity and genetic population structure of the Brazilian sharpnose shark Rhizoprionodon lalandii

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