Length-weight relationships of sharks caught by artisanal fisheries from southeastern Brazil

Motta, Fábio S.; Caltabellotta, Fabio P.; Namora, Rafael Cabrera; Gadig, Otto Bismarck Fazzano

doi:10.1111/jai.12234

Cited by 14 publications

(13 citation statements)

References 5 publications

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“…Fulton's condition Factor ( K ) was calculated for 3,962 females and 4,306 males by the expression K = M T ( L T b ) −1 (Fulton, ), where M T is the total body mass, L T total length and b is the regression coefficient of the length–mass relationship M T = a L T b . In the present study values for b of 3.22 and 3.13 were used for females and males, respectively (Motta et al, ). Linear regressions of M H and L T were calculated separately for females and males and then compared by analysis of co‐variance (ANCOVA).…”

Section: Methodsmentioning

confidence: 98%

Condition analysis of the Brazilian sharpnose shark Rhizoprionodon lalandii: evidence of maternal investment for initial post‐natal life

Corsso

Gadig

Barreto

et al. 2018

Journal of Fish Biology

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The present study analysed the condition factor (K) and the hepato-somatic index (I ) of the Brazilian sharpnose shark Rhizoprionodon lalandii during its entire life cycle. Discontinuity of liver growth was observed after sexual maturity. High condition values were recorded in the length classes of 300-350 mm (neonates), when the livers represented about 8% of total mass, decreasing until the length classes of 400-450 mm and 450-500 mm in females and males, respectively. Seasonal analysis exhibited low I values in the summer, while for K, low values were in spring, indicating greater investment for body growth during spring and for gonad maturation in summer. Such findings indicate that this small coastal shark species accumulates reserve substances in the liver that will be used during reproduction. The decline in I values in juveniles suggests that reserves provisioned by the mother to the neonate liver can be used in the first months of life. This article is protected by copyright. All rights reserved.

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Section: Methodsmentioning

confidence: 98%

Condition analysis of the Brazilian sharpnose shark Rhizoprionodon lalandii: evidence of maternal investment for initial post‐natal life

Corsso

Gadig

Barreto

et al. 2018

Journal of Fish Biology

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“…Hubungan panjang total dan berat tubuh (HPB) dianalisis dengan rumus: W = aL T b dengan W adalah berat tubuh dalam gram, L T adalah panjang total dalam cm, a dan b adalah konstanta (Effendie, 2002;Güven et al, 2012) dengan bantuan Microsoft Excel. Nilai b diuji ketepatannya terhadap nilai b = 3 menggunakan uji-t dengan tingkat kepercayaan 95% (Motta et al, 2014). Analisis untuk menduga ukuran panjang ratarata ikan pada saat 50% populasi pertama kali matang gonad (Lm) menggunakan metode kurva logistik (King, 2007) dengan persamaan: P = 1/ (1+exp[-r(L T -Lm)]) dengan P = probabilitas dari ukuran rata-rata ikan matang gonad, r = slope, L T = panjang total ikan dan Lm = ukuran panjang ikan saat rata-rata populasi sudah matang gonad.…”

Section: Analisis Dataunclassified

NISHAH KELAMIN, HUBUNGAN PANJANG-BERAT DAN UKURAN REPRODUKSI HIU Hexanchus spp. DI PERAIRAN SELATAN NUSA TENGGARA

Sentosa

2019

BERITABIOLOGI

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Hexanchus spp. are shark species that are often caught in the Indian Ocean southern Nusa Tenggara and its status is Near Threatened, but the information is still relatively limited. This study aimed to sex ratio, length-weight relationship and reproductive size of sixgill shark, Hexanchus spp. caught from southern Nusa Tenggara waters. This study had been carried out during 2016 at the Fishing Port of Tanjung Luar, East Lombok, West Nusa Tenggara. Shark data collection was done by measuring the length, weight, maturity and fishing data. Data were analyzed by formula of sex ratio, length-weight relationship, length at first maturity (Lm) and length at first catch (Lc). The results showed that Hexanchus spp. caught in the southern Nusa Tenggara waters consisted of H. nakamurai (81.82%) and H. griseus (18.18%). The sex ratio of both sharks was dominated by the female. The average of the total length of H. griseus (218.3 ± 96.08 cm). It was longer than H. nakamurai (127.6 ± 30.35 cm). The length-weight relationship of H. griseus was formulated as W = 0.0195 LT 2,6344 (R² = 0,9265) and H. nakamurai with the formula W = 0.002 LT 3,1098 (R² = 0.902). Both species have the size of Lm was bigger than the size of Lc which indicated to their population vulnerability.

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“…The causes for fetal mummification are either intrinsic, such as genetic and anatomic conditions, or environmental, such as drought, contamination or infectious pathologies (Lefebvre, 2015 (Compagno, 1984). In southern and southeastern Brazilian waters, females give birth from 2 to 33 embryos measuring about 40-50 cm total length, and parturition takes place in coastal areas in mid and late summer (Motta et al, 2014;Vooren & Klippel, 2005). (47.57 ± 1.02, n = 7) and from 480 to 584 g (523.7 ± 36.8, n = 7) in the right uterus and from 43.5 to 49.0 cm (47.40 ± 2.43, n = 5) and from 386 to 582 g (526.0 ± 82.3, n = 5) in the left uterus, respectively (Figure 1a).…”

Section: Introductionmentioning

confidence: 99%

Report on fetal mummification in the scalloped hammerhead shark Sphyrna lewini

Martins

Rolim

Gadig

2020

Journal of Fish Biology

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This study describes the fetal mummification process in two embryos of a 310 cm total length scalloped hammerhead shark Sphyrna lewini caught in southeastern Brazil, in December 2017. Fourteen embryos were observed in total, in which two males in the left uterus presented different stages of mummification. Both mummified embryos were covered by an exudate (i.e., a mucous substance), indicating a hematic mummification process. All embryos were at the placentotrophic stage of development, indicating that they were close to parturition. An intrinsic characteristic is suggested as possible etiology for this condition, such as umbilical torsion, because both embryos were at different sizes and, therefore, at different development stages.

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Length-weight relationships of sharks caught by artisanal fisheries from southeastern Brazil

Abstract: Summary Presented are the length‐weight relationships for eight shark species (Families Carcharhinidae and Sphyrnidae) caught by the small‐scale fishery in southeastern Brazil, from July 1996 to December 2003.

Cited by 14 publications

References 5 publications

Condition analysis of the Brazilian sharpnose shark Rhizoprionodon lalandii: evidence of maternal investment for initial post‐natal life

Condition analysis of the Brazilian sharpnose shark Rhizoprionodon lalandii: evidence of maternal investment for initial post‐natal life

NISHAH KELAMIN, HUBUNGAN PANJANG-BERAT DAN UKURAN REPRODUKSI HIU Hexanchus spp. DI PERAIRAN SELATAN NUSA TENGGARA

Report on fetal mummification in the scalloped hammerhead shark Sphyrna lewini

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